Inside Your Inkjet Printer: How Does It Work?

Have you ever wondered how your inkjet printer works?How does the ink get from the inkjet cartridge to the paper? Why is theprint quality is so clear? Why the printing is so quiet?Generally, all that most people know is that there's some movement anda faint high pitched sound when it's printing something -- and then thefinished document comes out.Unlike dot matrix and character printers that strike ribbons to createan image, inkjet printers do not physically touch the paper.All inkjet printers function using the same basic principles. Tiny inkdroplets are "jetted" (or pushed) out multiple holes onto paper in acontrolled and systematic fashion. This is where the term "inkjet"comes from.The size of ink droplets, speed and reliability of this type of printerhas been continuously improving since its inception in 1976. In 1993,Epson was the first manufacturer to produce an inkjet printer usingmicro-piezo technology. The Epson Stylus 800 was the first printer touse the multi-layer actuator printhead (the printhead is the part ofthe printer that holds numerous tiny nozzles that actually squirts theink onto paper).This specific print head utilised an electro-mechanical element thatacted like a tiny control room. When pulses of electricity passedthrough, it that gave specific signals to fire individual or multiplenozzles loaded with ink.Micro-piezo technology utilized a tiny crystal in each individualnozzle that when electrically energized, would vibrate or bend causinga controlled amount of ink to be forced out onto paper. When theelectrical current is off, the crystal bends back to its originalshape, creating a vacuum, thus pulling ink into the nozzle from thereservoir for the next commanded fire.Some printers have the cartridges fixed to the carriage so it neverneeded replacing (the printer carriage is what moves laterally acrossthe paper). This also kept the cost of ink cartridges low since theywere little more than reservoirs of ink.These breakthrough printers produced a whopping 360 dpi (dots per inch)that was deemed, almost "letter quality" at the time. With a printingspeed of 150 - 180 characters per second, the new Epson became the userfavorite printer for home and office.At the same time, other printers used a similar style, by which athermal jetting system was utilized in their printhead. The printheadstill acted like the control room but each individual nozzle wasinstead independently super heated by electricity, which caused the inkto explode onto the paper. Claims were made that the temperature of afired inkjet nozzle approaches that of the surface of the sun.In some printers, it was decided to mount the printhead on the inkjetcartridge itself instead of mounting it permanently to the carriage.Since each inkjet cartridge would have its own print head, replacementcartridges would be more expensive for these printers. The thermalinkjet cartridges could not print as fast because each nozzle needed tocool after firing. This heating technology also limited the types ofinks that could be used. In the 1990's professionals engineeredprint heads that applied even smaller droplets of ink, drasticallyimproving dpi and resolution. Some of the printers on the market couldproduce a 6 - 10 picoliter droplet size from one nozzle, while otherswere about half the size (between 3 - 6 picoliters). Currently, thereare printers available which will produce an amazing 1 picoliterdroplet! To get an idea of how small this is; a human hair is about 12picoliters in diameter. Most human eyes can't see one jetted droplet ofink on paper. Inkjet printers have come a long way since their firstinception. Printers today are twice as fast as their predecessors were,and are cheaper than ever. Many printers can easily produce color photoquality images in at an incredible 6000 dpi. As time goes on and asdemand for printing remains high, the quality, speed and features ofinkjet printers will only continue to improve.

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