HP printer cartridges
HP printer cartridges
As well as other peripherals, HP printer cartridges and toner are a big market for HP. These are generally for use in laser printers and photocopiers as opposed to inkjet printers. A laser printer is also a very common type of high quality computer printer. HP printer cartridges use a xerographic printing process but unlike their predecessors, the analog versions, a laser beam scans across the printer’s photoreceptor to produce the image. The image of the page is then projected onto an electrically charged rotating drum which is covered with selenium. The drum’s charged areas then picks up the dry ink particles and prints the image by fusing the ink to the paper through contact and heat.
The laser printer was invented at Xerox in 1969 by one of their researchers, however the first commercial version was said to ‘take up the whole room’. It wasn’t until 1984 that HP developed the first laser printer for the mass market and they were a revolution due to the speed at which they could print Now the faster models can print 12,000 pages an hour and the latest colour versions can print over 6000 pages an hour!
Rather than using liquid ink, HP printer cartridges or toner cartridges use a toner powder which was originally made of carbon but is now blended with a polymer called Styrene Acrylate Copolymer or a Polyester Resin. The particles of the toner get heated by a fuser causing them to bind to the paper.
Originally toner particle size was on average 14-16 micrometres or bigger and the toner had to be poured into the printer from a jar or bottle. Those days are gone! In order to improve the resolution of an image, particle size was reduced to 8-10 micrometres. Research and development is underway to reduce particle size even further through technologies such as Emulsion-Aggregation. Also, modern machines ensure that the toner is fed directly from the cartridge.
The toner was originally formed by mixing the ingredients to create a large slab which was then pounded into a fine powder by air jet milling. However, if you viewed the particles under a microscope, you would see that they were jagged and of varying shapes and sizes. Now, companies are using a chemical process to grow toner particles which makes them smaller, gives a them a more uniform size and shape which ultimately provides a finer print, more accurate colour and generally a more efficient toner.