10/24: Output: Printers Types of printers: laser, inkjet, dot-matrix printers Other types: plotters,...

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Transcript of 10/24: Output: Printers Types of printers: laser, inkjet, dot-matrix printers Other types: plotters,...

  • 10/24: Output: PrintersTypes of printers: laser, inkjet, dot-matrix printersOther types: plotters, label printers, digital presses, photo printers, electrostatic printers, LED printersHow color printing worksWhat to look for in a printer

  • Printers: GeneralPrinterstwo main groups: impact (dot-matrix, daisy-wheel) & nonimpact (laser, inkjet, thermal)other types: plotters, label printers, digital presses, photo printers, large-format printerscolor printingdot matrix printer image courtesy of epson.com, others courtesy of hp.com

  • Impact PrintersDot-Matrix printers: Pins are pushed by solenoids to hit a ribbon in front of the paper.Daisy-Wheel printers: Letters are pushed to hit the ribbon in front of the paper.Stamp ink onto the paper.Advantages: cheap, reliable, low CPU demand, multiple-form copyingDisadvantages: loud, slowimages courtesy of How Computers Work and Brother.com

  • Non-Impact: Inkjet PrintersThe ink cartridges have tiny heating elements that cause microdrops of ink to heat up and expand, shooting out of the nozzle and onto the paper.Advantage: cheap color printingimages courtesy of HP.com and How Computers Work

  • The ink cartridge(s)nozzle firing chamberpath from reservoir thin-film resistor

    Cross-section of a nozzle.

    How does the ink get out? One of two ways: The Thermal method or the Piezo-Electric method.The Ink Cartridge

  • NozzleFiring ChamberResistorHow the ink gets out: thermal methodUsed by Hewlett Packard & CanonA thin-film resistor is heated by electric current.The resistor heats up the ink that is next to it.

  • How the ink gets out: thermal methodThe ink- now gaseous - expands, forming a bubble.The bubble pushes out the rest of the ink in the firing chamber.

    NozzleFiring ChamberResistor

  • How the ink gets out: thermal methodThe resistor cools, causing the bubble to shrink.The shrinking creates a vacuum, which draws new ink from the reservoir.

    NozzleFiring ChamberResistor The piezo method uses a flexing, swelling crystal instead of heat to push the ink out.

  • Laser PrintersDeposit toner onto the paper, then melt it to make it permanent.Cheaper by the day per page printing costs are very low.Faster than inkjet printers.Very quiet.

    images courtesy of How Computers Work

  • Laser printingThe pattern to be printed is set up in a grid of black areas and white areas.The laser beams, horizontal line by horizontal line, this grid of dark areas.

  • Laser printingWhen the drum is hit with the laser beam, it electrically charges the coating at that spot.In HP & Canon printers, the coating is positively charged.

  • Laser printingAs the drum rolls by, the positively charged parts of the coating on the drum attract the toner particles.

  • Laser printingThe sheet of paper touches the drum coated in toner. The toner jumps to the paper from the drum because the paper is more strongly charged than the drum.

  • Laser printingThe paper, with the toner particles, goes to the fusing rollers. The rollers use pressure and heat to bind the toner to the paper permanently.

  • How Color Printing Workssubtractive colormonitors use additive color: all colors combine to get lighter shadesprinters combine colors to get darker shadesall colors together create black

  • Looking at printers in adsGo to http://www.buy.comthings to note when comparison shopping:what YOU will be using the printer forppm (pages per minute) in b&w, colorsize limitations of paperpaper tray capacityprice (and price of ink/toner cartridges)dpi (dots per inch) print quality capabilities(inkjets) type of black printing: separate cartridge?