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Unformatted text preview: All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 22 C HAPTER Printers 22 In this chapter, you will learn how to
• Describe current printer technologies
• Explain the laser printing process
• Install a printer on a Windows PC
• Recognize and fix basic printer problems Despite all of the talk about the “paperless office,” printers continue to be a vital part of
the typical office. In many cases, PCs are used exclusively for the purpose of producing
paper documents. Many people simply prefer dealing with a hard copy. Programmers
cater to this preference by using metaphors such as page, workbook, and binder in their
applications. The CompTIA A+ certification strongly stresses the area of printing and
expects a high degree of technical knowledge of the function, components, maintenance, and repair of all types of printers. Essentials
No other piece of your computer system is available in a wider range of styles, configurations, and feature sets than a printer, or at such a wide price variation. What a printer
can and can’t do is largely determined by the type of printer technology it uses—that is,
how it gets the image onto the paper. Modern printers can be categorized into several
broad types: impact, inkjet, dye-sublimation, thermal, laser, and solid ink. Impact Printers
Printers that create an image on paper by physically striking an ink ribbon against the
paper’s surface are known as impact printers. Although daisy-wheel printers (essentially an
electric typewriter attached to the PC instead of directly to a keyboard) have largely disappeared, their cousins, dot-matrix printers, still soldier on in many offices. Although dotmatrix printers don’t deliver what most home users want—high-quality and flexibility at
a low cost—they’re still widely found in businesses for two reasons: dot-matrix printers 973 ch22.indd 973 12/9/09 5:09:38 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 22 CompTIA A+Certification All-in-One Exam Guide 974 have a large installed base in businesses, and they can be used for multipart forms because they actually strike the paper. Impact printers tend to be relatively slow and noisy,
but when speed, flexibility, and print quality are not critical, they provide acceptable
results. PCs used for printing multipart forms, such as point of sale (POS) machines that
need to print receipts in duplicate, triplicate, or more, represent the major market for
new impact printers, although many older dot-matrix printers remain in use.
Dot-matrix printers use a grid, or matrix, of tiny pins, also known as printwires, to
strike an inked printer ribbon and produce images on paper (Figure 22-1). The case
that holds the printwires is called a printhead. Using either 9 or 24 pins, dot-matrix
printers treat each page as a picture broken up into a dot-based raster image. The
9-pin dot-matrix printers are generically called draft quality, while the 24-pin printers
are known as letter quality or near-letter quality (NLQ). The BIOS for the printer (either
built into the printer or a printer driver) interprets the raster image in the same way a
monitor does, “painting” the image as individual dots. Naturally, the more pins, the
higher the resolution. Figure 22-2 illustrates the components common to dot-matrix
printers. Many dot-matrix printers use continuous-feed paper with holes on its sides
that are engaged by metal sprockets to pull the paper through—this is known as tractorfeed paper because the sprockets are reminiscent of the wheels on a tractor.
An Epson FX880+ dot-matrix
courtesy of Epson
America, Inc.) Figure 22-2
Inside a dotmatrix printer ch22.indd 974 12/9/09 5:09:39 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 22
All-In-One Chapter 22: Printers 975 Inkjet Printers
Inkjet printers (also called ink-dispersion printers) like the one in Figure 22-3, are relatively
simple devices consisting of a printhead mechanism, support electronics, a transfer
mechanism to move the printhead back and forth, and a paper feed component to
drag, move, and eject paper (Figure 22-4). They work by ejecting ink through tiny tubes.
Most inkjet printers use heat to move the ink, while a few use a mechanical method.
The heat-method printers use tiny resistors or electroconductive plates at the end of
each tube that literally boil the ink; this creates a tiny air bubble that ejects a droplet of
ink onto the paper, thus creating a portion of the image (Figure 22-5). Figure 22-3
printer Figure 22-4
Inside an inkjet
printer The ink is stored in special small containers called ink cartridges. Older inkjet printers
had two cartridges: one for black ink and another for colored ink. The color cartridge
had separate compartments for cyan (blue), magenta (red), and yellow ink, to print
colors by using a method known as CMYK (you’ll read more about CMYK later in this
chapter). If your color cartridge ran out of one of the colors, you had to purchase a
whole new color cartridge or deal with a messy refill kit. ch22.indd 975 12/9/09 5:09:39 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 22 CompTIA A+Certification All-in-One Exam Guide 976 Figure 22-5
Detail of the
inkjet printhead Printer manufacturers began to separate the ink colors into three separate cartridges
so that printers came with four cartridges: one for each color and a fourth for black
(Figure 22-6). This not only was more cost-effective for the user, but it also resulted
in higher quality printouts. Today you can find color inkjet printers with six, eight, or
more color cartridges. In addition to the basic CMYK inks, the other cartridges provide
for green, blue, gray, light cyan, dark cyan, and more. Typically, the more ink cartridges
a printer uses, the higher the quality of the printed image—and the higher the cost of
cartridges The two key features of an inkjet printer are the print resolution—that is, the density
of ink, which affects print quality—and the print speed. Resolution is measured in dots
per inch (dpi); higher numbers mean that the ink dots on the page are closer together,
so your printed documents will look better. Resolution is most important when you’re ch22.indd 976 12/9/09 5:09:40 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 22
All-In-One Chapter 22: Printers 977 printing complex images such as full-color photos, or when you’re printing for duplication and you care that your printouts look good. Print speed is measured in pages per
minute (ppm), and this specification is normally indicated right on the printer’s box.
Most printers have one (faster) speed for monochrome printing—that is, using only
black ink—and another for full-color printing.
EXAM TIP Print resolution is measured in dots per inch (dpi) and print
speed is measured in pages per minute (ppm).
Another feature of inkjet printers is that they can support a staggering array of print
media. Using an inkjet printer, you can print on a variety of matte or glossy photo
papers, iron-on transfers, and other specialty media; some printers can print directly
onto specially coated optical discs, or even fabric. Imagine running a T-shirt through
your printer with your own custom slogan (how about “I’m CompTIA A+ Certified!”).
The inks have improved over the years, too, now delivering better quality and longevity
than ever. Where older inks would smudge if the paper got wet or start to fade after a
short time, modern inks are smudge proof and of archival quality—for example, some
inks by Epson are projected to last up to 200 years. Dye-Sublimation Printers
The term sublimation means to cause something to change from a solid form into a vapor
and then back into a solid. This is exactly the process behind dye-sublimation printing,
sometimes called thermal dye transfer printing. Dye-sublimation printers are used mainly
for photo printing, high-end desktop publishing, medical and scientific imaging, and
other applications for which fine detail and rich color are more important than cost and
speed. Smaller, specialized printers called snapshot printers use dye-sublimation specifically for printing photos at a reduced cost compared to their full-sized counterparts.
The dye-sublimation printing technique is an example of the so-called CMYK (cyan,
magenta, yellow, black) method of color printing. It uses a roll of heat-sensitive plastic
film embedded with page-sized sections of cyan (blue), magenta (red), and yellow
dye; many also have a section of black dye. A print head containing thousands of heating elements, capable of precise temperature control, moves across the film, vaporizing the dyes and causing them to soak into specially coated paper underneath before
cooling and reverting to a solid form. This
process requires one pass per page for each
color. Some printers also use a final finishThe dyeing pass that applies a protective laminate
coating to the page. Figure 22-7 shows how
a dye-sublimation printer works.
Documents printed through the dyesublimation process display continuoustone images, meaning that the printed image is not constructed of pixel dots but a continuous blend of overlaid differing dye
colors. This is in contrast to other print technologies’ dithered images, which use closely ch22.indd 977 12/9/09 5:09:41 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 22 CompTIA A+Certification All-in-One Exam Guide 978 packed, single-color dots to simulate blended colors. Dye-sublimation printers produce high-quality color output that rivals professional photo lab processing. Thermal Printers
Thermal printers use a heated printhead to create a high-quality image on special or
plain paper. You’ll see two kinds of thermal printers in use. The first is the direct thermal
printer, and the other is the thermal wax transfer printer. Direct thermal printers burn
dots into the surface of special heat-sensitive paper. If you remember the first generation
of fax machines, you’re already familiar with this type of printer. Many retail businesses
still use it as a receipt printer. Thermal wax printers work similarly to dye-sublimation
printers, except that instead of using rolls of dye-embedded film, the film is coated with
colored wax. The thermal printhead passes over the film ribbon and melts the wax onto
the paper. Thermal wax printers don’t require special papers like dye-sublimation printers, so they’re more flexible and somewhat cheaper to use, but their output isn’t quite
as good because they use color dithering. Laser Printers
Using a process called electro-photographic imaging, laser printers produce high-quality
and high-speed output of both text and graphics. Figure 22-8 shows a typical laser
printer. Laser printers rely on the photoconductive properties of certain organic
compounds. Photoconductive means that
particles of these compounds, when exprinter
posed to light (that’s the “photo” part),
will conduct electricity. Laser printers usually use lasers as a light source because of
their precision. Some lower-cost printers
use LED arrays instead.
The first laser printers created only monochrome images. Today, you can also buy a
color laser printer, although the vast majority of laser printers produced today are still
monochrome. Although a color laser printer can produce complex full-color images
such as photographs, they really shine for printing what’s known as spot color—for example, eye-catching headings, lines, charts, or other graphical elements that dress up an
otherwise plain printed presentation.
NOTE Some printers use consumables—such as ink—at a much faster rate
than others, prompting the industry to rank printers in terms of their cost
per page. Using an inexpensive printer (laser or inkjet) costs around 4 cents
per page, while an expensive printer can cost more than 20 cents per page—a
huge difference if you do any volume of printing. This hidden cost is particularly pernicious
in the sub-$100 inkjet printers on the market. Their low prices often entice buyers, who
then discover that the cost of consumables is outrageous—these days, a single set of color
and black inkjet cartridges can cost as much as the printer itself, if not more! ch22.indd 978 12/9/09 5:09:41 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 22
All-In-One Chapter 22: Printers 979 Critical Components of the Laser Printer
The CompTIA A+ certification exams take a keen interest in the particulars of the laser
printing process, so it pays to know your way around a laser printer. Let’s take a look at
the many components of laser printers and their functions (Figure 22-9).
inside a laser
printer Toner Cartridge The toner cartridge in a laser printer is so named because of its most
obvious activity: supplying the toner that creates the image on the page (Figure 22-10). To
reduce maintenance costs, however, many other laser printer parts, especially those that
suffer the most wear and tear, have been incorporated into the toner cartridge. Although
this makes replacement of individual parts nearly impossible, it greatly reduces the need
for replacement; those parts that are most likely to break are replaced every time you replace the toner cartridge.
toner cartridge NOTE Color laser printers have four toner cartridges: black, cyan, magenta,
and yellow. Photosensitive Drum The photosensitive drum is an aluminum cylinder coated
with particles of photosensitive compounds. The drum itself is grounded to the power ch22.indd 979 12/9/09 5:09:42 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 22 CompTIA A+Certification All-in-One Exam Guide 980 supply, but the coating is not. When light hits these particles, whatever electrical charge
they may have “drains” out through the grounded cylinder.
Erase Lamp The erase lamp exposes the entire surface of the photosensitive drum
to light, making the photosensitive coating conductive. Any electrical charge present in
the particles bleeds away into the grounded drum, leaving the surface particles electrically neutral.
Primary Corona The primary corona wire, located close to the photosensitive
drum, never touches the drum. When the primary corona is charged with an extremely
high voltage, an electric field (or corona) forms, enabling voltage to pass to the drum
and charge the photosensitive particles on its surface. The primary grid regulates the
transfer of voltage, ensuring that the surface of the drum receives a uniform negative
voltage of between ~600 and ~1000 volts.
Laser The laser acts as the writing mechanism of the printer. Any particle on the
drum struck by the laser becomes conductive and its charge is drained away into the
grounded core of the drum. The entire surface of the drum has a uniform negative
charge of between ~600 and ~1000 volts following its charging by the primary corona
wire. When particles are struck by the laser, they are discharged and left with a ~100 volt
negative charge. Using the laser, we can “write” an image onto the drum. Note that the
laser writes a positive image to the drum.
Toner The toner in a laser printer is a fine powder made up of plastic particles bonded
to iron particles. The toner cylinder charges the toner with a negative charge of between
~200 and ~500 volts. Because that charge falls between the original uniform negative
charge of the photosensitive drum (~600 to ~1000 volts) and the charge of the particles
on the drum’s surface hit by the laser (~100 volts), particles of toner are attracted to the
areas of the photosensitive drum that have been hit by the laser (that is, areas that have
a relatively positive charge with reference to the toner particles).
EXAM TIP The toner used in laser printers is typically carbon melt mixed
with a polyester resin.
Transfer Corona To transfer the image from the photosensitive drum to the paper, the paper must be given a charge that will attract the toner particles off of the
drum and onto the paper. The transfer corona is a thin wire, usually protected by other
thin wires, that applies a positive charge to the paper, drawing the negatively charged
toner particles to the paper. The paper, with its positive charge, is also attracted to the
negatively charged drum. To prevent the paper from wrapping around the drum, a static
charge eliminator removes the charge from the paper.
In most laser printers, the transfer corona is outside the toner cartridge, especially
in large commercial grade machines. The transfer corona is prone to a build-up of dirt,
toner, and debris through electrostatic attraction, and it must be cleaned. It is also quite
fragile—usually finer than a human hair. Most printers with an exposed transfer corona
provide a special tool to clean it, but you can also—very delicately—use a cotton swab ch22.indd 980 12/9/09 5:09:42 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 22
All-In-One Chapter 22: Printers 981 soaked in 90 percent denatured alcohol (don’t use rubbing alcohol because it contains
emollients). As always, never service any printer without first turning it off and unplugging it from its power source.
Fuser Assembly The fuser assembly is almost always separate from the toner cartridge. It is usually quite easy to locate as it is close to the bottom of the toner cartridge
and usually has two rollers to fuse the toner. Sometimes the fuser is somewhat enclosed
and difficult to recognize because the rollers are hidden from view. To help you determine the location of the fuser, think about the data path of the paper and the fact that
fusing is the final step of printing.
The toner is merely resting on top of the paper after the static charge eliminator has
removed the paper’s static charge. The toner must be permanently attached to the paper
to make the image permanent. Two rollers, a pressure roller and a heated roller, are
used to fuse the toner to the paper. The pressure roller presses against the bottom of the
page, and the heated roller presses down on the top of the page, melting the toner into
the paper. The heated roller has a nonstick coating such as Teflon to prevent the toner
from sticking to the heated roller.
Power Supplies All laser printers have at least two separate power supplies. The
first power supply is called the primary power supply or sometimes just the power supply. This power supply, which may actually be more than one power supply, provides
power to the motors that move the paper, the system electronics, the laser, and the
transfer corona. The high-voltage power supply usually provides power only to the primary corona. The extremely high voltage of the high-voltage power supply makes it one
of the most dangerous devices in the world of PCs! Before opening a printer to insert a
new toner cartridge, it is imperative that you always turn off a laser printer!
Turning Gears A laser printer has many mechanical functions. First, the paper
must be picked up. Next, the photosensitive roller must be turned and the laser, or a
mirror, must be moved from left to right. The toner must be evenly distributed, and the
fuser assembly must squish the toner into the paper. Finally, the paper must be kicked
out of the printer and the assembly cleaned to prepare for the next page.
All of these functions are served by complex gear systems. In most laser printers,
these gear systems are packed together in discrete units generically called gear packs or
gearboxes. Most laser printers have two or three gearboxes that you can remove relatively
easily in the rare case when one of them fails. Most gearboxes also have their own motor or solenoid to move the gears.
System Board Every laser printer contains at least one electronic board. On this
board is the main processor, the printer’s ROM, and the RAM used to store the image
before it is printed. Many printers divide these functions among two or three boards
dispersed around the printer. An older printer may also have an extra ROM chip and/or
a special slot where you can install an extra ROM chip, usually for special functions
such as PostScript.
On some printer models you can upgrade the contents of these ROM chips (the firmware) by performing a process called flashing the ROM. Flashing is a lot like upgrading ch22.indd 981 12/9/09 5:09:43 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 22 CompTIA A+Certification All-in-One Exam Guide 982 the system BIOS, which you learned about in Chapter 7, “BIOS and CMOS.” Upgrading
the firmware can help fix bugs, add new features, or update the fonts in the printer.
Of particular importance is the printer’s RAM. When the printer doesn’t have enough
RAM to store the image before it prints, you get a memory overflow problem. Also,
some printers store other information in the RAM, including fonts or special commands. Adding RAM is usually a simple job—just snapping in a SIMM or DIMM stick
or two—but getting the right RAM is important. Call or check the printer manufacturer’s
Web site to see what type of RAM you need. Although most printer companies will happily sell you their expensive RAM, most printers can use generic DRAM like the kind
you use in a PC.
Ozone Filter The coronas inside laser printers generate ozone (O3). Although not
harmful to humans in small amounts, even tiny concentrations of ozone will cause
damage to printer components. To counter this problem, most laser printers have a
special ozone filter that needs to be vacuumed or replaced periodically.
Sensors and Switches Every laser printer has a large number of sensors and
switches spread throughout the machine. The sensors are used to detect a broad range
of conditions such as paper jams, empty paper trays, or low toner levels. Many of these
sensors are really tiny switches that detect open doors and so on. Most of the time these
sensors/switches work reliably, yet occasionally they become dirty or broken, sending
a false signal to the printer. Simple inspection is usually sufficient to determine if a
problem is real or just the result of a faulty sensor/switch. Solid Ink
Solid ink printers use just what you’d expect—solid inks. The technology was originally
developed by Tektronix, whose printer division was acquired by Xerox. Solid ink printers
use solid sticks of nontoxic “ink” that produce more vibrant color than other print methods. The solid ink is melted and absorbed into the paper fibers; it then solidifies, producing a continuous-tone output. Unlike dye-sublimation printers, all colors are applied to
the media in a single pass, reducing the chances of misalignment. Solid ink sticks do not
rely on containers like ink for inkjet printers and can be “topped off” midway through a
print job by inserting additional color sticks without taking the printer offline.
These printers are fast, too! A full-color print job outputs the first page in about six
seconds. Of course, all that speed and quality comes at a price. Xerox’s base model starts
at about twice the cost of a laser printer, with the expensive model selling for about six
times the cost! Solid ink printers become a bit more affordable when you factor in the
cost of consumables. A single stick of ink costs about as much as an inkjet cartridge,
for example, but with a print capacity of 1000 pages, that completely beats the cost of
inkjet cartridges over time. Printer Languages
Now that you’ve learned about the different types of print devices and techniques, it’s
time to take a look at how they communicate with the PC. How do you tell a printer to
make a letter A or to print a picture of your pet iguana? Printers are designed to accept ch22.indd 982 12/9/09 5:09:43 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 22
All-In-One Chapter 22: Printers 983 predefined printer languages that handle both characters and graphics. Your software
must use the proper language when communicating with your printer, so that your
printer can output your documents onto a piece of paper. Following are the more common printer languages. ASCII
You might think of the American Standard Code for Information Interchange (ASCII) language as nothing more than a standard set of characters, the basic alphabet in upper
and lowercase with a few strange symbols thrown in. ASCII actually contains a variety
of control codes for transferring data, some of which can be used to control printers.
For example, ASCII code 10 (or 0A in hex) means “Line Feed,” and ASCII code 12 (0C)
means “Form Feed.” These commands have been standard since before the creation of
IBM PCs, and all printers respond to them. If they did not, the PRT SCR (print screen) key
would not work with every printer. Being highly standardized has advantages, but the
control codes are extremely limited. Printing high-end graphics and a wide variety of
fonts requires more advanced languages. PostScript
Adobe Systems developed the PostScript page description language in the early 1980s as
a device-independent printer language capable of high-resolution graphics and scalable
fonts. PostScript interpreters are embedded in the printing device. Because PostScript is
understood by printers at a hardware level, the majority of the image processing is done
by the printer and not the PC’s CPU, so PostScript printers print faster. PostScript defines
the page as a single raster image; this makes PostScript files extremely portable—they
can be created on one machine or platform and reliably printed out on another machine
or platform (including, for example, high-end typesetters). Hewlett-Packard Printer Control Language (PCL)
Hewlett-Packard developed its printer control language (PCL) as a more advanced printer
language to supersede simple ASCII codes. PCL features a set of printer commands
greatly expanded from ASCII. Hewlett-Packard designed PCL with text-based output
in mind; it does not support advanced graphical functions. The most recent version
of PCL, PCL6 features scalable fonts and additional line drawing commands. Unlike
PostScript, however, PCL is not a true page description language; it uses a series of commands to define the characters on the page. Those commands must be supported by
each individual printer model, making PCL files less portable than PostScript files. Windows GDI and XPS
Windows 2000/XP use the graphical device interface (GDI) component of the operating
system to handle print functions. Although you can use an external printer language
such as PostScript, most users simply install printer drivers and let Windows do all the
work. The GDI uses the CPU rather than the printer to process a print job and then
sends the completed job to the printer. When you print a letter with a TrueType font in
Windows, for example, the GDI processes the print job and then sends bitmapped images of each page to the printer. The printer sees a page of TrueType text, therefore, as a ch22.indd 983 12/9/09 5:09:43 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 22 CompTIA A+Certification All-in-One Exam Guide 984 picture, not as text. As long as the printer has a capable enough raster image processor
(explained later in this chapter) and plenty of RAM, you don’t need to worry about the
printer language in most situations. We’ll revisit printing in Windows in more detail
later in this chapter.
Windows Vista supports GDI printing, but it also includes a new printing subsystem
called the XML Paper Specification (XPS) print path. XPS provides several improvements
over GDI, including enhanced color management (which works with Windows Color
System) and better print layout fidelity. The XPS print path requires a driver that supports XPS. Additionally, some printers natively support XPS, eliminating the requirement that the output be converted to a device-specific printer control language before
printing. Printer Connectivity
Most printers connect to one of two ports on the PC: a DB-25 parallel port or a USB
port. The parallel connection is the classic way to plug in a printer, but most printers
today use USB. You’ll need to know how to support the more obscure parallel ports,
cables, and connections as well as the plug-and-play USB connections. Parallel Communication and Ports
The parallel port was included in the original IBM PC as a faster alternative to serial communication. The IBM engineers considered serial communication, limited to 1 bit at a
time, to be too slow for the “high-speed” devices of the day (for example, dot-matrix
printers). The standard parallel port has been kept around for backward compatibility
despite several obvious weaknesses.
Parallel ports may be far faster than serial ports, but they are slow by modern standards. The maximum data transfer rate of a standard parallel port is still only approximately 150 kilobytes per second (KBps). Standard parallel communication on the PC
also relies heavily on software, eating up a considerable amount of CPU time that could
be used better.
NOTE Although the phrase “Centronics standard” was common in the
heyday of parallel ports, no such animal actually existed. Prior to the
development of IEEE 1284, a very loose set of standards were adopted by
manufacturers in an attempt to reduce incompatibility issues somewhat.
Parallel ports are hindered by their lack of true bidirectional capability. Although
one-way communication was acceptable for simple line printers and dot-matrix printers, parallel communication also became popular for a wide range of external devices
that required two-way communication. Although it is possible to get two-way communication out of a standard parallel port, the performance is not impressive.
NOTE Many techs confuse the concept of duplex printing—a process
that requires special printers capable of printing on both sides of a sheet of
paper—with bidirectional printing. They are two different things! ch22.indd 984 12/9/09 5:09:43 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 22
All-In-One Chapter 22: Printers 985 IEEE 1284 Standard
In 1991, a group of printer manufacturers proposed to the Institute of Electrical and
Electronics Engineers (IEEE) that a committee be formed to propose a standard for a
backward-compatible, high-speed, bidirectional parallel port for the PC. The committee
was the IEEE 1284 committee (hence the name of the standard).
The IEEE 1284 standard requires the following:
• Support for five distinct modes of operation: compatibility mode, nibble mode, byte
mode, EPP, and ECP
• A standard method of negotiation for determining which modes are supported
both by the host PC and by the peripheral device
• A standard physical interface (that is, the cables and connectors)
• A standard electrical interface (that is, termination, impedance, and so on)
Because only one set of data wires exists, all data transfer modes included in the IEEE
1284 standard are half-duplex: Data is transferred in only one direction at a time.
NOTE The five modes of operation for parallel printing specified in the
IEEE 1284 standard (compatibility, nibble, byte, EPP, ECP) are inching closer
to obsolescence as USB printers take over the market. If you find yourself
needing to optimize the performance of a legacy parallel printer, you can look
up these modes by name, using various Web search tools. Parallel Connections, Cabling, and Electricity
Although no true standard exists, standard parallel cable usually refers to a printer cable
with the previously mentioned male DB-25 connector on one end and a 36-pin Centronics connector on the other (Figure 22-11). The shielding (or lack thereof) of the internal
wiring and other electrical characteristics of a standard parallel printer cable are largely
undefined except by custom. In practice, these standard cables are acceptable for transferring data at 150 KBps, and for distances of less than 6 feet, but they would be dangerously unreliable for some transfer modes. Figure 22-11
cable with 36-pin
Centronics connector on one
end and DB-25
connector on the
other ch22.indd 985 12/9/09 5:09:44 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 22 CompTIA A+Certification All-in-One Exam Guide 986 For more reliability at distances up to 32 feet (10 meters), use proper IEEE 1284compliant cabling. The transfer speed drops with the longer cables, but it does work,
and sometimes the trade-off between speed and distance is worth it.
Installing a parallel cable is a snap. Just insert the DB-25 connector into the parallel
port on the back of the PC and insert the Centronics connector into the printer’s Centronics port, and you’re ready to go to press!
NOTE Some printers come with both USB and parallel connections, but this
has become very rare. If you need a parallel printer for a system, be sure to
confirm that the particular model you want will work with your system! USB Printers
New printers now use USB connections that you can plug into any USB port on your
computer. USB printers don’t usually come with a USB cable, so you need to purchase
one when you purchase a printer. (It’s quite a disappointment to come home with your
new printer only to find you can’t connect it because it didn’t come with a USB cable.)
Most printers use the standard USB type A connector on one end and the smaller USB
type B connector on the other end, although some use two type A connectors. Whichever
configuration your USB printer has, just plug in the USB cable—it’s literally that easy!
NOTE In almost all cases, you must install drivers before you plug a USB
printer into your computer. You’ll learn about installing printer drivers later
in this chapter. FireWire Printers
Some printers offer FireWire connections in addition to or instead of USB connections.
A FireWire printer is just as easy to connect as a USB printer, because FireWire is also
hot-swappable and hot-pluggable. Again, make sure you have the proper cable, as most
printers don’t come with one. If your printer has both connections, which one should
you use? The answer is easy if your PC has only USB and not FireWire. If you have a
choice, either connection is just as good as the other, and the speeds are comparable. If
you already have many USB devices, you may want to use the FireWire printer connection, to leave a USB port free for another device. Network Printers
Connecting a printer to a network isn’t just for offices anymore. More and more homes
and home offices are enjoying the benefits of network printing. It used to be that to
share a printer on a network—that is, to make it available to all network users—you
would physically connect the printer to a single computer and then share the printer
on the network. The downside to this was that the computer to which the printer was
connected had to be left on for others to use the printer.
Today, the typical network printer comes with its own onboard network adapter that
uses a standard RJ-45 Ethernet cable to connect the printer directly to the network by ch22.indd 986 12/9/09 5:09:44 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 22
All-In-One Chapter 22: Printers 987 way of a router. The printer can typically be assigned a static IP address, or it can acquire
one dynamically from a DHCP server. (Don’t know what a router, IP address, or DHCP
server is? Take a look at Chapter 23, “Local Area Networking.”) Once connected to the
network, the printer acts independent of any single PC. Some of the more costly network printers come with a built-in Wi-Fi adapter to connect to the network wirelessly.
Alternatively, some printers offer Bluetooth interfaces for networking.
Even if a printer does not come with built-in Ethernet, Wi-Fi, or Bluetooth, you can
purchase a stand-alone network device known as a print server to connect your printer to
the network. These print servers, which can be Ethernet or Wi-Fi, enable one or several
printers to attach via parallel port or USB. So take that ancient ImageWriter dot-matrix
printer and network it—I dare you! Other Printers
Plenty of other connection types are available for printers. We’ve focused mainly on
parallel, USB, FireWire, and networked connections. Be aware that you may run into
an old serial port printer or a SCSI printer. Although this is unlikely, know that it’s a
possibility. Practical Application
The Laser Printing Process
The laser printing process can be broken down into six steps, and the CompTIA A+ exams expect you to know them all. As a tech, you should be familiar with these phases,
as this can help you troubleshoot printing problems. For example, if an odd line is
printed down the middle of every page, you know there’s a problem with the photosensitive drum or cleaning mechanism and the toner cartridge needs to be replaced.
You’ll look into the physical steps that occur each time a laser printer revs up and
prints a page; then you’ll see what happens electronically to ensure that the data is processed properly into flawless, smooth text and graphics. The Physical Side of the Process
Most laser printers perform the printing process in a series of six steps. Keep in mind
that some brands of laser printers may depart somewhat from this process, although
most work in exactly this order:
6. Fuse ch22.indd 987 12/9/09 5:09:44 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 22 CompTIA A+Certification All-in-One Exam Guide 988 EXAM TIP Be sure that you know the order of a laser printer’s printing
process! Here’s a mnemonic to help: Clarence Carefully Wrote Down The
Facts. Clean the Drum
The printing process begins with the physical and electrical cleaning of the photosensitive drum (Figure 22-12). Before printing each new page, the drum must be returned
to a clean, fresh condition. All residual toner left over from printing the previous page
must be removed, usually by scraping the surface of the drum with a rubber cleaning
blade. If residual particles remain on the drum, they will appear as random black spots
and streaks on the next page. The physical cleaning mechanism either deposits the
residual toner in a debris cavity or recycles it by returning it to the toner supply in the
toner cartridge. The physical cleaning must be done carefully. Damage to the drum will
cause a permanent mark to be printed on every page. Figure 22-12
erasing the drum The printer must also be electrically cleaned. One or more erase lamps bombard the
surface of the drum with the appropriate wavelengths of light, causing the surface particles to discharge into the grounded drum. After the cleaning process, the drum should
be completely free of toner and have a neutral charge. Charge the Drum
To make the drum receptive to new images, it must be charged (Figure 22-13). Using
the primary corona wire, a uniform negative charge is applied to the entire surface of
the drum (usually between ~600 and ~1000 volts). Write and Develop the Image
A laser is used to write a positive image on the surface of the drum. Every particle on the
drum hit by the laser releases most of its negative charge into the drum. Those particles
with a lesser negative charge are positively charged relative to the toner particles and
attracts them, creating a developed image (Figure 22-14). ch22.indd 988 12/9/09 5:09:45 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 22
All-In-One Chapter 22: Printers 989 Figure 22-13
drum with a
charge Figure 22-14
Writing the image
and applying the
toner Transfer the Image
The printer must transfer the image from the drum onto the paper. The transfer corona
gives the paper a positive charge; then the negatively charged toner particles leap from
the drum to the paper. At this point, the particles are merely resting on the paper and
must still be permanently fused to the paper. Fuse the Image
The particles have been attracted to the paper because of the paper’s positive charge, but
if the process stopped here, the toner particles would fall off the page as soon as you
lift it. Because the toner particles are mostly composed of plastic, they can be melted
to the page. Two rollers—a heated roller coated in a nonstick material and a pressure
roller—melt the toner to the paper, permanently affixing it.
CAUTION The heated roller produces enough heat to melt some types of
plastic media, particularly overhead transparency materials. This could damage
your laser printer (and void your warranty), so make sure you’re printing on
transparencies designed for laser printers! ch22.indd 989 12/9/09 5:09:45 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 22 CompTIA A+Certification All-in-One Exam Guide 990 Finally, a static charge eliminator removes the paper’s positive charge (Figure 22-15).
Once the page is complete, the printer ejects the printed copy and the process begins
again with the physical and electrical cleaning of the printer.
image to the
paper and fusing
the final image NOTE Color laser printers use four different colors of toner (cyan, magenta,
yellow, and black) to create their printouts. Most models put each page through
four different passes, adding one color at each pass to create the needed
results, while others place all the colors onto a special belt and then transfer
them to the page in one pass. In some cases, the printer uses four separate toner cartridges
and four lasers for the four toner colors, and in others the printer simply lays down one
color after the other on the same drum, cleaning after each of four passes per page. The Electronic Side of the Process
When you click the Print button in an application, several things happen. First, the
CPU processes your request and sends a print job to an area of memory called the print
spooler. The print spooler enables you to queue up multiple print jobs that the printer
will handle sequentially. Next, Windows sends the first print job to the printer. That’s
your first potential bottleneck—if it’s a big job, the OS has to dole out a piece at a time
and you’ll see the little printer icon in the notification area at the bottom right of your
screen. Once the printer icon goes away, you know the print queue is empty—all jobs
have gone to the printer.
Once the printer receives some or all of a print job, the hardware of the printer takes
over and processes the image. That’s your second potential bottleneck and has multiple
components. Raster Images
Impact printers transfer data to the printer one character or one line at a time, whereas
laser printers transfer entire pages at a time to the printer. A laser printer generates a raster ch22.indd 990 12/9/09 5:09:46 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 22
All-In-One Chapter 22: Printers 991 image (a pattern of dots) of the page, representing what the final product should look
like. It uses a device (the laser) to “paint” a raster image on the photosensitive drum.
Because a laser printer has to paint the entire surface of the photosensitive drum before
it can begin to transfer the image to paper, it processes the image one page at a time.
A laser printer uses a chip called the raster image processor (RIP) to translate the raster
image into commands to the laser. The RIP takes the digital information about fonts
and graphics and converts it to a rasterized image made up of dots that can then be
printed. An inkjet printer also has a RIP, but it’s part of the software driver instead of
onboard hardware circuitry. The RIP needs memory (RAM) to store the data that it
must process. A laser printer must have enough memory to process an entire page.
Some images that require high resolutions require more memory. Insufficient memory
to process the image will usually be indicated by a memory overflow (“MEM OVERFLOW”) error. If you get a memory overflow error, try reducing the resolution, printing
smaller graphics, or turning off RET (see the following section for the last option). Of
course, the best solution to a memory overflow error is simply to add more RAM to the
Do not assume that every error with the word memory in it can be fixed simply by
adding more RAM to the printer. Just as adding more RAM chips will not solve every
conventional PC memory problem, adding more RAM will not solve every laser printer
memory problem. The message “21 ERROR” on an HP LaserJet, for example, indicates
that “the printer is unable to process very complex data fast enough for the print engine.” This means that the data is simply too complex for the RIP to handle. Adding
more memory would not solve this problem; it would only make your wallet lighter.
The only answer in this case is to reduce the complexity of the page image (that is, fewer
fonts, less formatting, reduced graphics resolution, and so on).
NOTE Inkjet printers use RIPs as well, but they’re written into the device
drivers instead of the onboard programming. You can also buy third-party
RIPs that can improve the image quality of your printouts; for an example, see
Laser printers can print at different resolutions, just as monitors can display different
resolutions. The maximum resolution that a laser printer can handle is determined by
its physical characteristics. Laser printer resolution is expressed in dots per inch (dpi).
Common resolutions are 600 × 600 dpi or 1200 × 1200 dpi. The first number, the
horizontal resolution, is determined by how fine a focus can be achieved by the laser. The second number is determined by the smallest increment by which the drum
can be turned. Higher resolutions produce higher quality output, but keep in mind
that higher resolutions also require more memory. In some instances, complex images
can be printed only at lower resolutions because of their high-memory demands. Even
printing at 300 dpi, laser printers produce far better quality than dot-matrix printers
because of resolution enhancement technology (RET).
RET enables the printer to insert smaller dots among the characters, smoothing
out the jagged curves that are typical of printers that do not use RET (Figure 22-16). ch22.indd 991 12/9/09 5:09:46 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 22 CompTIA A+Certification All-in-One Exam Guide 992 Using RET enables laser printers to output high-quality print jobs, but it also requires a
portion of the printer’s RAM. If you get a MEM OVERFLOW error, sometimes disabling
RET will free up enough memory to complete the print job. Figure 22-16 RET fills in gaps with smaller dots to smooth out jagged characters. Installing a Printer in Windows
You need to take a moment to understand how Windows handles printing, and then you’ll
see how to install, configure, and troubleshoot printers in these operating systems.
EXAM TIP The CompTIA A+ exams test you on installing and
troubleshooting printers, so read these sections carefully!
To Windows 2000, XP, and Vista/7, a printer is not a physical device; it is a program
that controls one or more physical printers. The physical printer is called a print device
to Windows (although I continue to use the term “printer” for most purposes, just like
almost every tech on the planet). Printer drivers and a spooler are still present, but in
Windows 2000/XP and Vista/7, they are integrated into the printer itself (Figure 22-17).
This arrangement gives Windows amazing flexibility. For example, one printer can support multiple print devices, enabling a system to act as a print server. If one print device
goes down, the printer automatically redirects the output to a working print device.
The general installation, configuration, and troubleshooting issues are basically
identical in all modern versions of Windows. Here’s a review of a typical Windows
printer installation. I’ll mention the trivial differences among Windows 2000, XP, and
Vista as I go along. Setting Up Printers
Setting up a printer is so easy that it’s almost scary. Most printers are plug and play, so
installing a printer is reduced to simply plugging it in and loading the driver if needed. ch22.indd 992 12/9/09 5:09:46 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 22
All-In-One Chapter 22: Printers 993 Figure 22-17
and spooler in
Windows Printer Print device Print
driver Spooler If the system does not detect the printer or if the printer is not plug and play, click Start
| Printers and Faxes in Windows XP to open the Printers applet; in Windows 2000, click
Start | Settings | Printers. For Windows Vista, you need to open up the Control Panel
and find the Printer menu item—it is either by itself or, in the categorized view, under
Hardware. You can also find the icon for this applet in the Control Panel of Windows
As you might guess, you install a new printer by clicking the Add a Printer icon
(somehow Microsoft has managed to leave the name of this applet unchanged through
all Windows versions since 9x). This starts the Add Printer Wizard. After a pleasant intro screen, you must choose to install either a printer plugged directly into your system
or a network printer (Figure 22-18). You also have the Automatically detect and install
My Plug and Play printer option, which you can use in many cases when installing a
USB printer. Figure 22-18
Choosing local or
in Windows XP ch22.indd 993 12/9/09 5:09:48 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 22 CompTIA A+Certification All-in-One Exam Guide 994 If you choose a local printer (see Chapter 23, “Local Area Networking,” for a discussion of networked printers), the applet next asks you to select a port; select the one
where you installed the new printer (Figure 22-19). Once you select the port, Windows
asks you to specify the type of printer, either by selecting the type from the list or by using the Have Disk option, just as you would for any other device (Figure 22-20). Note
the handy Windows Update button, which you can use to get the latest printer driver
from the Internet. When you click Next on this screen, Windows installs the printer.
Selecting a port
in Windows XP Figure 22-20
Selecting a printer
Windows XP Figure 22-21 shows a typical Windows XP Printers and Faxes screen on a system with
one printer installed. Note the small checkmark in the icon’s corner; this shows that the
device is the default printer. If you have multiple printers, you can change the default
printer by selecting the printer’s properties and checking Make Default Printer. ch22.indd 994 12/9/09 5:09:49 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 22
All-In-One Chapter 22: Printers 995 Figure 22-21 Installed default printer in the Printers and Faxes applet In addition to the regular driver installation outlined previously, some installations
use printer emulation. Printer emulation simply means using a substitute printer driver
for a printer, as opposed to using one made exclusively for that printer. You’ll run into
printer emulation in two circumstances. First, some new printers do not come with their
own drivers. They instead emulate a well-known printer (such as an HP LaserJet 4) and
run perfectly well on that printer driver. Second, you may see emulation in the “I don’t
have the right driver!” scenario. I keep about three different HP LaserJet and Epson ink
jet printers installed on my PC because I know that with these printer drivers, I can print
to almost any printer. Some printers may require you to set them into an emulation mode
to handle a driver other than their native one.
NOTE You’ve seen how to get your system to recognize a printer, but
what do you do when you add a brand-new printer? Like most peripherals,
the printer will include an installation CD-ROM that contains various useful
files. One of the most important but least used tools on this CD-ROM is the
Readme file. This file, generally in TXT format, contains the absolute latest information on
any idiosyncrasies, problems, or incompatibilities related to your printer or printer driver.
Usually, you can find it in the root folder of the installation CD-ROM, although many
printer drivers install the Readme file on your hard drive so you can access it from the
Start menu. The rule here is read first to avoid a headache later! ch22.indd 995 12/9/09 5:09:49 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 22 CompTIA A+Certification All-in-One Exam Guide 996 Optimizing Print Performance
Although a quality printer is the first step toward quality output, your output relies on
factors other than the printer itself. What you see on the screen may not match what
comes out of the printer, so calibration is important. Using the wrong type of paper can
result in less than acceptable printed documents. Configuring the printer driver and
spool settings can also affect your print jobs. Calibration
If you’ve ever tweaked that digital photograph so it looks perfect on screen, only to
discover that the final printout was darker than you had hoped, consider calibrating
your monitor. Calibration matches the print output of your printer to the visual output
on your monitor and governs that through software. All three parts need to be set up
properly for you to print what you see consistently.
Computer monitors output in RGB—that is, they compose colors using red, green,
and blue pixels, as discussed in Chapter 19, “Video”—while printers mix their colors
differently to arrive at their output. As mentioned earlier, the CMYK method composes
colors from cyan (blue), magenta (red), yellow, and black.
EXAM TIP Remember for the Exams, the RGB color display model is used
for displaying mixtures of red, green, and blue. The CMYK color printing
model uses cyan, magenta, yellow, and black for producing colored printed
The upshot of all this is that the printer tries to output—by using CMYK (or another
technique)—what you see on the screen using RGB. Because the two color modes do
not create color the same way, you see color shifts and not-so-subtle differences between the onscreen image and the printed image. By calibrating your monitor, you
can adjust the setting to match the output of your printer. You can do this manually
through “eyeballing” it or automatically by using calibration hardware.
To calibrate your monitor manually, obtain a test image from the Web (try sites such
as www.DigitalDog.net) and print it out. If you have a good eye, you can compare this
printout to what you see on the screen and make the adjustments manually through
your monitor’s controls or display settings.
Another option is to calibrate your printer by using an International Color Consortium (ICC) color profile, a preference file that instructs your printer to print colors a
certain way—for example, to match what is on your screen. Loading a different color
profile results in a different color output. Color profiles are sometimes included on
the installation CD-ROM with a printer, but you can create or purchase custom profiles as well. The use of ICC profiles is not limited to printers; you can also use them
to control the output of monitors, scanners, or even digital cameras. Windows Vista
includes Windows Color System (WCS) to help build color profiles for use across devices. WCS is based on a new standard Microsoft calls color infrastructure and translation
engine (CITE). ch22.indd 996 12/9/09 5:09:50 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 22
All-In-One Chapter 22: Printers 997 Troubleshooting Printers
As easy as printers are to set up, they are equally robust at running, assuming that you
install the proper drivers and keep the printer well maintained. But printer errors do
occasionally develop. Take a look at the most common print problems with Windows,
as well as problems that crop up with specific printer types. General Troubleshooting Issues
Printers of all stripes share some common problems, such as print jobs that don’t go,
strangely sized prints, and misalignment. Other issues include consumables, sharing
multiple printers, and crashing on power-up. Let’s take a look at these general troubleshooting issues, but start with a recap of the tools of the trade. Tools of the Trade
Before you jump in and start to work on a printer that’s giving you fits, you’ll need some
tools. You can use the standard computer tech tools in your toolkit, plus a couple of
printer-specific devices. Here are some that will come in handy:
• A multimeter for troubleshooting electrical problems such as faulty wall outlets
• Various cleaning solutions, such as denatured alcohol
• An extension magnet for grabbing loose screws in tight spaces and cleaning up
• An optical disc or USB thumb drive with test patterns for checking print quality
• Your trusty screwdriver—both a Phillips-head and flat-head, because if you
bring just one kind, it’s a sure bet that you’ll need the other Print Job Never Prints
If you click Print but nothing comes out of the printer, first check all the obvious things.
Is the printer on? Is it connected? Is it online? Does it have paper? Assuming the printer
is in good order, it’s time to look at the spooler. You can see the spooler status either
by double-clicking the printer’s icon in the Printers applet or by double-clicking the
tiny printer icon in the notification area if it’s present. If you’re having a problem, the
printer icon will almost always be there. Figure 22-22 shows the print spooler open.
Print spooler ch22.indd 997 12/9/09 5:09:51 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 22 CompTIA A+Certification All-in-One Exam Guide 998 Print spoolers can easily overflow or become corrupt due to a lack of disk space, too
many print jobs, or one of a thousand other factors. The status window shows all of the
pending print jobs and enables you to delete, start, or pause jobs. I usually just delete
the affected print job(s) and try again.
Print spoolers are handy. If the printer goes down, you can just leave the print jobs in
the spooler until the printer comes back online. Some versions of Windows require you
to select Resume Printing manually, but others automatically continue the print job(s).
If you have a printer that isn’t coming on anytime soon, you can simply delete the print
job in the spooler window and try another printer.
If you have problems with the print spooler, you can get around them by changing your
print spool settings. Go into the Printers and Faxes applet, right-click the icon of the printer
in question, and choose Properties. In the resulting Properties window (see Figure 22-23),
choose the Print directly to the printer radio button and click OK; then try sending your print
job again. Note that this window also offers you the choice of printing immediately—that
is, starting to print pages as soon as the spooler has enough information to feed to the
printer—or holding off on printing until the entire job is spooled.
settings Another possible cause for a stalled print job is that the printer is simply waiting
for the correct paper! Laser printers in particular have settings that tell them what size
paper is in their standard paper tray or trays. If the application sending a print job specifies a different paper size—for example, it wants to print a standard No. 10 envelope, or
perhaps a legal sheet, but the standard paper tray holds only 8.5 × 11 letter paper—the
printer usually pauses and holds up the queue until someone switches out the tray or
manually feeds the type of paper that this print job requires. You can usually override
this pause, even without having the specified paper, by pressing the OK or GO button
on the printer. ch22.indd 998 12/9/09 5:09:51 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 22
All-In-One Chapter 22: Printers 999 The printer’s default paper tray and paper size options will differ greatly depending
on the printer type and model. To find these settings, go into the printer’s Properties
window from the Printers and Faxes applet, and then select the Device Settings tab. This
list of settings includes Form To Tray Assignment, where you can specify which tray (in
the case of a printer with multiple paper trays) holds which size paper.
If you’ve double-checked your print spool settings and your paper sizes but the dang
printer still won’t print, it’s time to fall back on a tried-and-true technique that usually
works surprisingly well: turn the printer off and then back on. CompTIA calls this process power cycling. Also, make sure to check that the printer is actually plugged into your
computer. You would be amazed how many printer issues (and just computer issues in
general) arise because of a loose or unplugged cord.
EXAM TIP CompTIA calls the process of turning the printer off and back on
power cycling, which has nothing at all to do with Lance Armstrong. Strange Sizes
A print job that comes out a strange size usually points to a user mistake in setting up the
print job. All applications have a Print command and a Page Setup interface. The Page
Setup interface enables you to define a number of print options, which vary from application to application. Figure 22-24 shows the Page Setup options for Microsoft Word.
Make sure the page is set up properly before you blame the printer for a problem.
If you know the page is set up correctly, recheck the printer drivers. If necessary, uninstall and reinstall the printer drivers. If the problem persists, you may have a serious
problem with the printer’s print engine, but that comes up as a likely answer only when
you continually get the same strangely sized printouts using a variety of applications.
Microsoft Word ch22.indd 999 12/9/09 5:09:52 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 22 CompTIA A+Certification All-in-One Exam Guide 1000 Misaligned or Garbage Prints
Misaligned or garbage printouts invariably point to a corrupted or incorrect driver.
Make sure you’re using the right driver (it’s hard to mess this up, but not impossible)
and then uninstall and reinstall the printer driver. If the problem persists, you may be
asking the printer to do something it cannot do. For example, you may be printing to
a PostScript printer with a PCL driver. Check the printer type to verify that you haven’t
installed the wrong type of driver for that printer! Dealing with Consumables
All printers tend to generate a lot of trash in the form of consumables. Impact printers
use paper and ribbons, inkjet printers use paper and ink cartridges, and laser printers
use paper and toner cartridges. In today’s environmentally sensitive world, many laws
regulate the proper disposal of most printer components. Be sure to check with the
local sanitation department or disposal services company before throwing away any
component. Of course, you should never throw away toner cartridges—certain companies will pay for used cartridges!
When in doubt about what to do with a component, check with the manufacturer for a
material safety data sheet (MSDS). These standardized forms provide detailed information
about the potential environmental hazards associated with different components and
proper disposal methods. For example, surf to www.hp.com/hpinfo/globalcitizenship/
environment/productdata/index.html to find the latest MSDS for all Hewlett-Packard
products. This isn’t just a printer issue—you can find an MSDS for most PC components.
When in doubt about how to get rid of any PC component, check with the manufacturer
for an MSDS.
EXAM TIP MSDS contain important information regarding hazardous
materials such as safe use procedures and emergency response instructions.
An MSDS is typically posted anywhere a hazardous chemical is used. Problems Sharing Multiple Printers
If you want to use multiple printers attached to the same parallel port, you have to use
a switch box. Laser printers should never be used with mechanical switch boxes. Mechanical switch boxes create power surges that can damage your printer. If you must use
a switch box, use a box that switches between printers electronically and has built-in
surge protection. Crashes on Power-up
Both laser printers and PCs require more power during their initial power-up (the POST
on a PC and the warm-up on a laser printer) than once they are running. HewlettPackard recommends a reverse power-up. Turn on the laser printer first and allow it to
finish its warm-up before turning on the PC. This avoids having two devices drawing
their peak loads simultaneously. ch22.indd 1000 12/9/09 5:09:52 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 22
All-In-One Chapter 22: Printers 1001 Troubleshooting Dot-Matrix Printers
Impact printers require regular maintenance but will run forever as long as you’re diligent. Keep the platen (the roller or plate on which the pins impact) clean and the printhead clean with denatured alcohol. Be sure to lubricate gears and pulleys according to
the manufacturer’s specifications. Never lubricate the printhead, however, because the
lubricant will smear and stain the paper. Bad-looking Text
White bars going through the text point to a dirty or damaged printhead. Try cleaning
the printhead with a little denatured alcohol. If the problem persists, replace the printhead. Printheads for most printers are readily available from the manufacturer or from
companies that rebuild them. If the characters look chopped off at the top or bottom,
the printhead probably needs to be adjusted. Refer to the manufacturer’s instructions
for proper adjustment. Bad-looking Page
If the page is covered with dots and small smudges—the “pepper look”—the platen
is dirty. Clean the platen with denatured alcohol. If the image is faded, and you know
the ribbon is good, try adjusting the printhead closer to the platen. If the image is okay
on one side of the paper but fades as you move to the other, the platen is out of adjustment. Platens are generally difficult to adjust, so your best plan is to take it to the
manufacturer’s local warranty/repair center. Troubleshooting Inkjet Printers
Inkjet printers are reliable devices that require little maintenance as long as they are
used within their design parameters (high-use machines will require more intensive
maintenance). Because of the low price of these printers, manufacturers know that people don’t want to spend a lot of money keeping them running. If you perform even the
most basic maintenance tasks, they will soldier on for years without a whimper. Inkjets
generally have built-in maintenance programs that you should run from time to time
to keep your inkjet in good operating order. Inkjet Printer Maintenance
Inkjet printers don’t get nearly as dirty as laser printers, and most manufacturers do
not recommend periodic cleaning. Unless your manufacturer explicitly tells you to do
so, don’t vacuum an inkjet. Inkjets generally do not have maintenance kits, but most
inkjet printers come with extensive maintenance software (Figure 22-25). Usually, the
hardest part of using this software is finding it in the first place. Look for an option in
Printing Preferences, a selection on the Start menu, or an icon on your desktop. Don’t
When you first set up an inkjet printer, it normally instructs you to perform a routine to
align the printheads properly, wherein you print out a page and select from sets of numbered lines. If this isn’t done, the print quality will show it, but the good news is that you
can perform this procedure at any time. If a printer is moved or dropped or it’s just been
working away untended for a while, it’s often worth running the alignment routine. ch22.indd 1001 12/9/09 5:09:52 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 22 CompTIA A+Certification All-in-One Exam Guide 1002 Figure 22-25
screen Inkjet Problems
Did I say that you never should clean an inkjet? Well, that may be true for the printer
itself, but there is one part of your printer that will benefit from an occasional cleaning: the inkjet’s printer head nozzles. The nozzles are the tiny pipes that squirt the ink
onto the paper. A common problem with inkjet printers is the tendency for the ink
inside the nozzles to dry out when not used even for a relatively short time, blocking
any ink from exiting. If your printer is telling Windows that it’s printing and it’s feeding paper through, but either nothing is coming out (usually the case if you’re just
printing black text), or only certain colors are printing, the culprit is almost certainly
dried ink clogging the nozzles.
NOTE All inkjet inks are water-based, and water works better than alcohol
to clean them up.
Every inkjet has a different procedure for cleaning the printhead nozzles. On older
inkjets, you usually have to press buttons on the printer to start a maintenance program. On more modern inkjets, you can access the head-cleaning maintenance program from Windows.
NOTE Cleaning the heads on an inkjet printer is sometimes necessary, but I
don’t recommend that you do it on a regular basis as preventive maintenance.
The head-cleaning process uses up a lot of that very expensive inkjet ink—so do
this only when a printing problem seems to indicate clogged or dirty print heads! ch22.indd 1002 12/9/09 5:09:53 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 22
All-In-One Chapter 22: Printers 1003 Another problem that sometimes arises is the dreaded multi-sheet paper grab. This
is often not actually your printer’s fault—humidity can cause sheets of paper to cling
to each other—but sometimes the culprit is an overheated printer, so if you’ve been
cranking out a lot of documents without stopping, try giving the printer a bit of a coffee
break. Also, fan the sheets of the paper stack before inserting it into the paper tray.
Finally, check to see if excess ink overflow is a problem. In the area where the printheads park, look for a small tank or tray that catches excess ink from the cleaning process. If the printer has one, check to see how full it is. If this tray overflows onto the main
board or even the power supply, it will kill your printer. If you discover that the tray is
about to overflow, you can remove excess ink by inserting a twisted paper towel into the
tank to soak up some of the ink. It is advisable to wear latex or vinyl gloves while doing
this. Clean up any spilled ink with a paper towel dampened with distilled water. Troubleshooting Laser Printers
Quite a few problems can arise with laser printers, but before getting into those details,
you need to review some recommended procedures for avoiding those problems.
CAUTION Before you service a laser printer, always, always turn it off and
unplug it! Don’t expose yourself to the very dangerous high voltages found
inside these machines. Laser Printer Maintenance
Unlike PC maintenance, laser printer maintenance follows a fairly well established procedure. Follow these steps to ensure a long, healthy life for your system.
Keep It Clean Laser printers are quite robust as a rule. A good cleaning every time
you replace the toner cartridge will help that printer last for many years. I know of many
examples of original HP LaserJet I printers continuing to run perfectly after a dozen or
more years of operation. The secret is that they were kept immaculately clean.
Your laser printer gets dirty in two ways: Excess toner, over time, will slowly coat
the entire printer. Paper dust, sometimes called paper dander, tends to build up where
the paper is bent around rollers or where pickup rollers grab paper. Unlike (black)
toner, paper dust is easy to see and is usually a good indicator that a printer needs to
be cleaned. Usually, a thorough cleaning using a can of pressurized air to blow out the
printer is the best cleaning you can do. It’s best to do this outdoors, or you may end
up looking like one of those chimney sweeps from Mary Poppins! If you must clean a
printer indoors, use a special low-static vacuum designed especially for electronic components (Figure 22-26).
Every laser printer has its own unique cleaning method, but the cleaning instructions tend to skip one little area. Every laser printer has a number of rubber guide
rollers through which the paper is run during the print process. These little rollers tend
to pick up dirt and paper dust over time, making them slip and jam paper. They are easily cleaned with a small amount of 90 percent or better alcohol on a fibrous cleaning ch22.indd 1003 12/9/09 5:09:53 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 22 CompTIA A+Certification All-in-One Exam Guide 1004 Figure 22-26
vacuum towel. The alcohol will remove the debris and any dead rubber. You can also give the
rollers and separator pads a textured surface that will restore their feeding properties by
rubbing them with a little alcohol on a nonmetallic scouring pad.
CAUTION The photosensitive drum, usually contained in the toner cartridge,
can be wiped clean if it becomes dirty, but be very careful if you do so! If the
drum becomes scratched, the scratch will appear on every page printed from
that point on. The only repair in the event of a scratch is to replace the toner
If you’re ready to get specific, get the printer’s service manual. Almost every printer
manufacturer sells these; they are a key source for information on how to keep a printer
clean and running. Sadly, not all printer manufacturers provide these, but most do.
While you’re at it, see if the manufacturer has a Quick Reference Guide; these can be
very handy for most printer problems!
Finally, be aware that Hewlett-Packard sells maintenance kits for most of its laser
printers. These are sets of replacement parts for the parts most likely to wear out on
each particular type of HP LaserJet. Although their use is not required to maintain
warranty coverage, using these kits when prescribed by HP helps assure the continuing
reliability of your LaserJet.
Periodic Maintenance Although keeping the printer clean is critical to its health
and well being, every laser printer has certain components that you need to replace
periodically. Your ultimate source for determining the parts that need to be replaced
(and when to replace them) is the printer manufacturer. Following the manufacturer’s
maintenance guidelines will help to ensure years of trouble-free, dependable printing
from your laser printer.
Many manufacturers provide kits that contain components that you should replace
on a regular schedule. These maintenance kits often include a fuser as well as one or
more rollers or pads. Typically, you need to reset the page counter after installing a
maintenance kit so the printer can remind you to perform maintenance again after a
certain number of pages have been printed.
Some ozone filters can be cleaned with a vacuum and some can only be replaced—
follow the manufacturer’s recommendation. You can clean the fuser assembly with ch22.indd 1004 12/9/09 5:09:54 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 22
All-In-One Chapter 22: Printers 1005 90 percent or better denatured alcohol. Check the heat roller (the Teflon coated one
with the light bulb inside) for pits and scratches. If you see surface damage on the rollers, replace the fuser unit.
Most printers will give you an error code when the fuser is damaged or overheating
and needs to be replaced; others will produce the error code at a preset copy count as a
preventive maintenance measure. Again, follow the manufacturer’s recommendations.
NOTE Failure of the thermal fuse (used to keep the fuser from overheating)
can necessitate replacing the fuser assembly. Some machines contain more
than one thermal fuse. As always, follow the manufacturer’s recommendations.
Many manufacturers have kits that alert you with an alarm code to replace the
fuser unit and key rollers and guides at predetermined page counts.
The transfer corona can be cleaned with a 90 percent denatured alcohol solution on
a cotton swab. If the wire is broken, you can replace it; many just snap in or are held
in by a couple of screws. Paper guides can also be cleaned with alcohol on a fibrous
CAUTION The fuser assembly operates at 200 to 300 degrees Fahrenheit, so
always allow time for this component to cool down before you attempt to
clean it. Laser Printer Problems
Laser printers usually manifest problems by creating poor output. One of the most
important tests you can do on any printer, not just a laser printer, is called a diagnostic
print page or an engine test page. You do this by either holding down the On Line button
as the printer is started or using the printer’s maintenance software.
Blank Paper Blank sheets of paper usually mean the printer is out of toner. If the
printer does have toner and nothing prints, print a diagnostic print page. If that is also
blank, remove the toner cartridge and look at the imaging drum inside. If the image is still
there, you know the transfer corona or the high-voltage power supply has failed. Check
the printer’s maintenance guide to see how to focus on the bad part and replace it.
Dirty Printouts If the fusing mechanism gets dirty in a laser printer, it will leave a
light dusting of toner all over the paper, particularly on the back of the page. When you
see toner speckles on your printouts, you should get the printer cleaned.
Ghosting Ghost images sometimes appear at regular intervals on the printed page.
This happens when the imaging drum has not fully discharged and is picking up toner
from a previous image or when a previous image has used up so much toner that either
the supply of charged toner is insufficient or the toner has not been adequately charged.
Sometimes it can also be caused by a worn-out cleaning blade that isn’t removing the
toner from the drum. ch22.indd 1005 12/9/09 5:09:54 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 22 CompTIA A+Certification All-in-One Exam Guide 1006 Light Ghosting versus Dark Ghosting A variety of problems can cause both
light and dark ghosting, but the most common source of light ghosting is “developer
starvation.” If you ask a laser printer to print an extremely dark or complex image, it can
use up so much toner that the toner cartridge will not be able to charge enough toner
to print the next image. The proper solution is to use less toner. You can fix ghosting
problems in the following ways:
• Lower the resolution of the page (print at 300 dpi instead of 600 dpi).
• Use a different pattern.
• Avoid 50 percent grayscale and “dot-on/dot-off patterns.”
• Change the layout so that grayscale patterns do not follow black areas.
• Make dark patterns lighter and light patterns darker.
• Print in landscape orientation.
• Adjust print density and RET settings.
• Print a completely blank page immediately prior to the page with the ghosting
image, as part of the same print job.
In addition to these possibilities, low temperature and low humidity can aggravate
ghosting problems. Check your users’ manual for environmental recommendations.
Dark ghosting can sometimes be caused by a damaged drum. It may be fixed by replacing the toner cartridge. Light ghosting would not be solved in this way. Switching other
components will not usually affect ghosting problems because they are a side effect of
the entire printing process.
Vertical White Lines Vertical white lines usually happen when the toner is
clogged, preventing the proper dispersion of toner on the drum. Try shaking the toner
cartridge to dislodge the clog. If that doesn’t work, replace the toner cartridge.
Blotchy Print Blotches are commonly a result of uneven dispersion of toner, especially if the toner is low. Shake the toner from side to side and then try to print. Also
be sure that the printer is sitting level. Finally, make sure the paper is not wet in spots. If
the blotches are in a regular order, check the fusing rollers and the photosensitive drum
for any foreign objects.
Spotty Print If the spots appear at regular intervals, the drum may be damaged or
some toner may be stuck to the fuser rollers. Try wiping off the fuser rollers. Check the
drum for damage. If the drum is damaged, get a new toner cartridge.
Embossed Effect If your prints are getting an embossed effect (like putting a penny
under a piece of paper and rubbing it with a lead pencil), there is almost certainly a
foreign object on a roller. Use 90 percent denatured alcohol or regular water with a
soft cloth to try to remove it. If the foreign object is on the photosensitive drum, you’re ch22.indd 1006 12/9/09 5:09:55 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 22
All-In-One Chapter 22: Printers 1007 going to have to use a new toner cartridge. An embossed effect can also be caused by
the contrast control being set too high. The contrast control is actually a knob on the
inside of the unit (sometimes accessible from the outside, on older models). Check
your manual for the specific location.
Incomplete Characters You can sometimes correct incompletely printed characters on laser-printed transparencies by adjusting the print density. Be extremely careful to use only materials approved for use in laser printers.
Creased Pages Laser printers have up to four rollers. In addition to the heat and
pressure rollers of the fuser assembly, other rollers move the paper from the source tray
to the output tray. These rollers crease the paper to avoid curling that would cause paper
jams in the printer. If the creases are noticeable, try using a different paper type. Cotton
bond paper is usually more susceptible to noticeable creasing than other bonds. You
might also try sending the output to the face-up tray, which avoids one roller. There is
no hardware solution to this problem; it is simply a side-effect of the process.
Paper Jams Every printer jams now and then. If you get a jam, always refer first to
the manufacturer’s jam removal procedure. It is simply too easy to damage a printer by
pulling on the jammed paper! If the printer reports a jam but there’s no paper inside,
you’ve almost certainly got a problem with one of the many jam sensors or paper feed
sensors inside the printer, and you’ll need to take it to a repair center.
Pulling Multiple Sheets If the printer grabs multiple sheets at a time, first try
opening a new ream of paper and loading that in the printer. If that works, you have a
humidity problem. If the new paper angle doesn’t work, check the separation pad on the
printer. The separation pad is a small piece of cork or rubber that separates the sheets as
they are pulled from the paper feed tray. A worn separation pad looks shiny and, well,
worn! Most separation pads are easy to replace. Check out www.printerworks.com to see
if you can replace yours.
Warped, Overprinted, or Poorly Formed Characters Poorly formed
characters can indicate either a problem with the paper (or other media) or a problem
with the hardware.
Incorrect media cause a number of these types of problems. Avoid paper that is too
rough or too smooth. Paper that is too rough interferes with the fusing of characters
and their initial definition. If the paper is too smooth (like some coated papers, for
example), it may feed improperly, causing distorted or overwritten characters. Even
though you can purchase laser printer–specific paper, all laser printers print acceptably
on standard photocopy paper. Try to keep the paper from becoming too wet. Don’t
open a ream of paper until it is time to load it into the printer. Always fan the paper
before loading it into the printer, especially if the paper has been left out of the package
for more than just a few days.
The durability of a well-maintained laser printer makes hardware a much rarer
source of character printing problems, but you should be aware of the possibility. ch22.indd 1007 12/9/09 5:09:55 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 22 CompTIA A+Certification All-in-One Exam Guide 1008 Fortunately, it is fairly easy to check the hardware. Most laser printers have a self-test
function—often combined with a diagnostic printout but sometimes as a separate process. This self-test shows whether the laser printer can properly develop an image without actually having to send print commands from the PC. The self-test is quite handy
to verify the question “Is it the printer or is it the computer?” Run the self-test to check
for connectivity and configuration problems.
Possible solutions include replacing the toner cartridge, especially if you hear popping noises; checking the cabling; and replacing the data cable, especially if it has bends
or crimps or if objects are resting on the cable. If you have a front menu panel, turn off
advanced functions and high-speed settings to determine whether the advanced functions are either not working properly or not supported by your current software configuration (check your manuals for configuration information). If these solutions do not
work, the problem may not be user serviceable. Contact an authorized service center. Beyond A+
The IEEE 1284.4 standard, commonly known as DOT4, was created for multifunction
peripherals (MFPs)—those nifty gadgets that combine the functions of printer, fax, and
scanner in one big piece of equipment (Figure 22-27). The DOT4 protocol enables the
individual devices within the MFP to send and receive multiple data packets simultaneously across a single physical channel. All data exchanges are independent of one
another, so you can cancel one—for example, a print job—without affecting the others. DOT4 is an enhancement of the IEEE 1284 protocol for parallel printing; look for
products that use it the next time you find yourself in a computer superstore. Figure 22-27
maker/iPod dock ch22.indd 1008 12/9/09 5:09:56 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 22
All-In-One Chapter 22: Printers 1009 Chapter Review Questions
1. What mechanism is used by most inkjet printers to push ink onto the paper?
A. Electrostatic discharge
C. Air pressure
D. Electroconductive plates
2. With a laser printer, what creates the image on the photosensitive drum?
A. Primary corona
B. Laser imaging unit
C. Transfer corona
3. What is the proper order of the laser printing process?
A. Clean, charge, write, develop, transfer, and fuse
B. Charge, write, transfer, fuse, develop, and clean
C. Clean, write, develop, transfer, fuse, and charge
D. Clean, charge, write, develop, fuse, and transfer
4. On a dot-matrix printer, what physically strikes the ribbon to form an image?
C. Character wheel
D. Print hammers
5. Which of these items are considered to be dot-matrix printer consumables?
(Select all that apply.)
A. Drive motor
6. What part must be vacuumed or replaced periodically to prevent damage caused
by the action of the corona?
A. The rubber rollers
B. The ozone filter
C. The transfer filter
D. The cleaning blade ch22.indd 1009 12/9/09 5:09:56 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 22 CompTIA A+Certification All-in-One Exam Guide 1010 7. Which of the following port types commonly support printers? (Select two.)
8. A standalone printer prints a test page just fine, but it makes gobbledygook out
of your term paper. What’s probably wrong?
A. Out of toner
B. Fuser error
C. Printer interface
D. Faulty software configuration
9. What printing process uses heat-sensitive plastic files embedded with various
10. Which tool would help you determine why a print job didn’t print?
A. Printer driver
B. Printer setup
C. Print spooler
D. System setup Answers
1. D. Most inkjet printers use electroconductive plates to push the ink onto the paper.
2. B. The laser imaging unit creates an image on the photosensitive drum.
3. A. Clean, charge, write, develop, transfer, and fuse is the proper process.
4. B. Printwires physically strike the ribbon in dot-matrix printers.
5. B, D. Both paper and ribbons are considered dot-matrix printer consumables.
6. B. The ozone filter should be periodically vacuumed or changed.
7. A, B. You’ll find almost all printers hooked up to parallel or USB ports.
8. D. The application (software) that is trying to print is probably configured
9. A. Dye-sublimation printers use heat sensitive plastic files embedded with
various color dyes
10. C. The print spooler can help you determine why a print job didn’t print. ch22.indd 1010 12/9/09 5:09:56 PM ...
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This note was uploaded on 04/27/2010 for the course COMPTIA 1201 taught by Professor N/a during the Spring '10 term at Galveston College.
- Spring '10