Inkjet Printing – Process and its applications in the manufacture of biosensors Introduction Inkjet printing is a non-impact dot-matrix digitally controlled printing technology, whereby droplets of fluid are propelled from a small aperture directly on to a specified position on a substrate. Lord Rayleigh first explained the concept of inket printing in 1878, in a series of papers based on liquid jets and their instability. He propositioned that a liquid stream of constant radius that is falling vertically under gravity, will begin to break up into droplets as soon as its critical point is reached. However, it was not until 1951 that his idea became more widely employed when Elmqvist of Siemens, patented the core technology for the first ever continuous inkjet printer. In subsequent years, this technology continued to be further developed, notably with the invention of the first ever drop-on-demand (DOD) piezoelectric printer in 1972. Since then, products have continued to be commercialized by major companies such as Epson, Hewlett-Packard and Canon. Initially applied to the graphic arts, inkjet printing has found ground in a variety of different fields. For example, it has now been applied to the printing of solar cells, light-emitting devices, organic thin-film transistors, detectors, and magnetic nanomaterials. Furthermore, advances in technology have proven its applications are no longer limited to two-dimensional structures, but that it is also now possible to print three-dimensional structures. One of the most attractive applications of inkjet printing is in the manufacture of biosensors, and this is what this report will focus on. Biosensors are an integral part of many aspects in modern life. Some examples of biosensors are the blood glucose biosensor, whole cell metabolism, and the antibody-antigen reaction. Previous research has found that it is possible to manufacture biosensors through the use of different techniques and technologies, however inkjet printing has been found to offer a number of benefits. Inkjet Printers 1
There are two fundamental technologies that are used in modern day inkjet printers: continuous (CIJ) and drop-on-demand (DOD). Continuous Inkjet Printer The continuous inkjet method is the oldest inkjet technology in use, and is widely employed for the marking and coding of products and packages. The printer functions by using a high-pressure pump to guide the ink or fluid from its reservoir to the substrate to which it is to be printed on to. At the same time, a piezoelectric crystal causes the nozzle to vibrate, resulting in the stream of fluid being ejected to disperse into droplets. The printer produces digital signals that selectively charge some of the droplets, and so these droplets then get directed to a gutter so that they can be re-used.
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- Fall '19
- Inkjet printer