3InkJet Printers Eject Ink through tiny tubes called jets. Usually there are four ink wells: Cyan, Magenta, Yellow and BlackResolution: How close the little dots can beSpeed: pages per minute. B&W usually faster than color
4Dye Sublimation Printers AKA thermal dye transferUsed in high-end applications (photos, publishing, medical)Continuous toneRivals photo lab processing from negative film
5Laser Printers Electro-photographic Printing Uses photo-conductive materials to “etch” an image using a laser beam.Very high quality print and graphics.Usually black and white.
6Toner Cartridge Contains Toner!!! Also contains many other parts: Photosensitive DrumPrimary Corona (Charging Roller)Developing Cylinder
7Photosensitive Drum Aluminum cylinder Coated with photosensitive particlesCylinder is grounded, particles are not.Particles are charged.When laser strikes the photosensitive drum, the charged particles “escape” to the grounded cylinder
8Erase Lamp Exposes all of the photosensitive drum to light. Leaves drum electrically neutral (i.e. ground)
9Primary Corona Very Close but not touching the Photosensitive Drum Handles extremely high voltage.Transfers a uniform negative voltage (-600 to Volts) to Photosensitive Drum
10Toner Toner is plastic covered iron Toner is charged (via developing cylinder) to about -200 VoltsToner is uniformly distributed on the developing cylinder (held there by magnetism.Toner is attracted to photosensitive drum where laser has hit.
12Transfer CoronaCharges the paper to attract the toner from the photosensitive drum.This is usually a very thin wire applying a positive charge to the paper.Prone to getting dirty.Must be cleanedVery fragile. DON’T BREAK!!!!!!
13Fuser AssemblyConsists of two slippery (Teflon) rollers (sometimes hidden) and a heater.One roller is heated, presses down on the paper, melts the toner into the paper.
14Other Parts Turning Gears: moves the paper and rollers Power Supplies: primary power runs motors, electronics and transfer corona. High voltage Supply for primary corona.System Board: processor, RAM, ROM, BIOS, Control CircuitsOzone Filter: eliminates O3Sensors/Switches: monitors status. Stops Fires
15Printer LanguagesASCII: American Standard Code for Information Interchange (Text and control)ascii.txtPostScript: created by Adobe. Printer independent language. Strengths were high resolution graphics and scalable fonts. sigcse97.txtPrinter Control Language: created by HP. Originally for text. PCL6 supports scalable fonts and drawing funtions.
16Graphical Device Interface Microsoft print handling componentUses the CPU (not the printer) to process a print job.Sends a “Raster” image to the printer.
17Printer ConnectionsParallel Port: Uses special cable to connect 25-pin printer port on computer to 36-pin Centronics port on printer.USB: Plug and Play???InfraRed
18IEEE 1284 Standard Specifies Cable and Electronics configuration. Centronics Mode: One way 8-bitsNibble mode: uses status wires to send 4-bit data back to computerByte Mode/BiDir: enables half-duplex 8-bit communicationEnhanced Parallel Port: Offloads overhead to parallel port away from CPU.ECP: uses DMA and data compression (run length encoding)
19Six Steps of Laser Printing CleaningCharge/ConditionWritingDevelopingTransferringFusingTake place inside toner cartridgeUse components that undergo the most wear
23Step 2: ConditioningPrimary Charging Roller conditions drum to contain a Uniform high electrical charge (-600 V)
24Step 3: WritingLaser beam discharges a lower charge to only those places where toner is to go
25Writing Mind-numbing Detail Uniform charge is discharged only where the laser beam hits (due to photosensitivity)Mirrors reflect the laser beam onto the DrumScanning Mirror directs beam across the pageMain mirror(as wide as the page) reflects beam onto drum through a slitFocusing lens sharpens the imageBeam detect causes DC controller to step the drum and start a new scan
26Step 4: DevelopingToner is placed onto the drum where the charge has been reduced
27Developing Mind-numbing Detail Charged (~-300V) Toner (resin coated iron) is attracted to the developing cylinder magneticallyControl blade creates even distributionCharged Toner is pulled off developing cylinder onto drumToner is charged by DC bias on Dev.Cyl. The amount of bias controls density
28Step 5: TransferringStrong electrical charge draws toner off drum onto paper; takes place outside the cartridge
29TransferingAs paper is feed to roller a transfer charging roller creates a positive chargeAs paper passes by drum, the toner is drawn to the positively charged paperAfter paper passes roller the static charge eliminator reduces the charge on the paper and the drum
30Step 6: FusingHeat and pressure fuse toner to paper
31Fusing Mind-numbing detail Fusing roller apply heat and pressure.Toner melts into paperIf temperature exceeds 410 degrees F the fusing system shuts down