Bài giảng Computer - Chapter 12

Chapter Overview Printer basicsPrinter portsDot-matrix printersInk-jet printersLaser printers 1Printer Basics Printer resolutionSpeedGraphics and printer-language supportPaper capacity Duty cyclePrinter memoryCost of paperCost of consumables 2Common Printer Terms American Standard Code for Information Interchange (ASCII)FontLine print terminal (LPT) portLaser Jet Printer Control Language (PCL)PostScriptResolution enhancementPrinting orientationDuplexing 3Printer Ports Ports can be serial, Small Computer System Interface (SCSI), or parallel, although parallel is the most common.The parallel port consists of a 25-pin male plug.Parallel ports have some disadvantages.The data transfer rate is only 150 KB per second.The parallel port uses system resources while printing.Parallel cables have a maximum effective length of 10 feet. 4Dot-Matrix Printers 5Maintaining a Dot-Matrix Printer Change the ribbon.Keep the printer clean.Keep the print head clean.Replace the print head if it fails. 6Troubleshooting Dot-Matrix Printers 7Ink-Jet Printers Spray ink onto paper to form imagesProvide good-quality, reasonably fast printingProduce color as well as black-and-white imagesHave replaced dot-matrix and thermal wax printers in the low-end market 8Maintaining an Ink-Jet Printer Keep the printer clean.Replace ink cartridges as needed. 9Troubleshooting Ink-Jet Printers 10Laser Printers Are nonimpact devices that precisely place toner on paperRange from low-volume, personal use to high-volume, multiuser useAre similar to office copiersAre more expensive to purchase, but cheaper to operateUse toner, which is more permanent than ink 11Laser Printer Components Paper transportLogic circuitsUser interfaceToner and toner cartridgesPhotosensitive drumLaser beam Primary coronaTransfer coronaFuser rollersErase lampPower supplyDrivers and software 12Computer-to-Printer Communication The operating system sends a request to the printer.The printer informs the operating system that it is online and ready to accept data.The PC starts sending data.The printer informs the computer of any problems it encountered.After the job is complete, the printer acknowledges the receipt of all data. 13The Laser Printing Process 14Laser Printer Resolution High resolution means better quality printing.Resolution is measured in dots per inch (dpi).Horizontal and vertical resolution are generally equal and are expressed as one measurement.Resolution 600 = 600 dpi  600 dpi Resolution 1200 = 1200 dpi  1200 dpi  Draft mode saves toner by printing at lower resolution. 15Troubleshooting Laser Printers Ghost imagesBlack pageBlack spots or streaksMarks on every pagePrinting too lightMemory overflow errorIncomplete charactersMelted plasticCreased pagesWarped, overprinted, or poorly formed charactersPersistent paper jam indicationContinued paper jam 16Hardware Problems Print diagnostic and configuration information.Check forStatus lightsMenu warningsError messages Use the manual to translate problems indicated by the printer display. 17Chapter Summary Dot-matrix printers are still used for printing multiple copies at once.Ink-jet printers provide good quality at an inexpensive price. Laser printers are more expensive initially but cheaper per page.Most printer problems can be resolved quickly by checking for incorrect connections, correcting improper use, or fixing paper jams.Key components of a laser printer are the photosensitive drum, erase lamp, primary corona, laser beam, transfer corona, and fuser rollers. 18