220-1201 Hardware Study Guide for the CompTIA A+ Core Series Exam

Printer Maintenance

Printers come in multiple varieties, each with unique components and maintenance requirements. For the CompTIA A+ exam, you should be able to perform the appropriate maintenance given a specific scenario.

Laser

Laser printers create high-quality printouts using a complex process. The component that actually “draws” the image is a laser, which works with other components to transfer that image to the paper.

Components

Laser printers have the following specific imaging parts:

• imaging drum—The laser draws the page image onto the imaging drum.

• fuser assembly—The fuser assembly applies pressure and heat to bond the toner to the paper.

• transfer belt—Used in color laser printers, the transfer belt transfers the page image from the imaging drum to the paper.

• transfer roller—Used in black-and-white laser printers, the transfer roller transfers the page image from the imaging drum to the paper.

• pickup rollers—Rubber pickup rollers feed paper from the paper tray through the printer.

• separation pads—To ensure that only one page is fed at a time, separation pads separate the page being fed from the pages underneath it.

• duplexing assembly—To print on both sides of the paper, the duplexing assembly will flip the paper over.

Imaging Process

The imaging process of a laser printer specifies the process the printer follows to produce an image. These are the steps of the process:

1. processing—Before any actual printing is done, the image of the full page is placed into memory.

2. charging—A high negative charge is applied to the imaging drum.

3. exposing—The laser draws the image of the page onto the imaging drum by exposing it to the laser light. The tightly focused laser light removes the negative charge from the imaging drum (neutralizing it), leaving the rest of the drum negatively charged.

4. developing—The negatively charged toner is transferred to the imaging drum. Since the drum is also negatively charged, the toner will only stick to the areas that have been neutralized by the laser.

5. transferring—The transfer roller or transfer belt transfers the toner from the drum to the paper.

6. fusing—A fusing roller uses heat and pressure to bond the toner to the paper.

7. cleaning—Any residual toner is cleaned off the imaging drum.

Maintenance

Laser printers tend to be expensive, so regular maintenance must be done to keep them running well for a long time. Manufacturers make this fairly easy for common maintenance tasks like replacing toner. Other tasks require more knowledge and skill. Regular maintenance can also alleviate common laser printing quality issues such as blurred or smeared prints and faint (ghosted) text. Here are some of the maintenance tasks that you need to know how to do:

• Replace the toner.—Toner is used for each print job, so it must periodically be replaced. Toner comes in a toner cartridge that is easily replaced by the user.

• Use the maintenance kit.—Printer manufacturers recommend replacing certain parts periodically. They provide these parts in maintenance kits. They may include the fuser assembly, transfer belt, transfer roller, pickup rollers, and/or separation pads.

• Calibrate the printer.—Calibration is done to keep the page image sharp and accurate. This may be done on a periodic basis and when parts are replaced. Each printer will have its own calibration process.

• Clean the toner residue.—Toner is a fine powder that will leave residue in the printer. Keeping the inside of the printer clean will keep it running well and prevent loose toner from showing up on printouts.

Inkjet

Inkjet printers create high-quality printouts, though the resolution can be less than that of laser printers. They are also much less expensive. They create the page image by spraying ink dots onto precise points on the paper. Several components work together to transfer the page image to the paper.

Components

Inkjet printers have the following specific imaging parts:

• ink cartridge—Ink is stored in ink cartridges, which supply that ink to the print heads. There may be a separate cartridge for each of the standard colors used: cyan, magenta, yellow, and black. Some inkjet printers use a combined color cartridge with cyan, magenta, and yellow ink, plus a separate black ink cartridge.

• print head—The print head draws the ink from the cartridge and ejects it onto the paper. Some printers combine the ink cartridge and the print head into a single unit.

• roller—Paper is fed through the printer by the roller.

• feeder—Paper may be fed from either a simple paper tray or a feeder. Most feeders have adjustments to allow you to feed papers of varied sizes.

• duplexing assembly—The duplexing assembly flips the paper over so that you can print on both sides. It is not found in all inkjet printers.

• carriage belt—The carriage and the belt form a single component known as the carriage belt. The carriage holds the print heads and gets moved into position so the print heads can eject the ink onto the proper spot on the paper. The belt moves the carriage into position so the print heads can eject the ink onto the proper spot on the paper.

Maintenance

Inkjet printers require minimal maintenance, which is easily done using features available through the printer’s menus or software. To determine if maintenance is needed, test pages that are specifically designed to point out flaws can be printed from the printer’s menus or software. Common inkjet print flaws include horizontal lines (known as banding) and blurred or smeared prints. Here are some basic maintenance steps you should know how to do:

• Clean the heads.—Printer heads can get clogged over time. Cleaning the heads can be done by selecting a menu option or through the printer’s software. When initiated, the printer will run through a head-cleaning process.

• Replace the ink cartridges.—When the ink in a cartridge has been used up, the cartridge must be replaced. A calibration should be done after replacing a cartridge.

• Calibrate the printer.—Calibration is done to keep the page image sharp and accurate. This should be done on a periodic basis and when parts are replaced, particularly whenever a print head or ink cartridge is replaced. Each printer will have its own calibration process.

• Clear any jams.—Paper may get jammed in the printer as it is fed through. It can be cleared manually by simply pulling it out. Some printers provide a way to run just the feeder, either manually by turning a wheel or by running the feed motor.

Thermal

Thermal printers use chemically treated thermal paper that changes color when heated. It is the heat, rather than ink, that transfers the image to the paper. Thermal printers are simple and inexpensive. Common uses are for receipts and shipping labels. The image printed is sensitive to light and heat, so it will fade over time.

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Elements

There are two main elements of a thermal printer:

• feed assembly—The feed assembly feeds the thermal paper through the printer.

• heating element—The heating element heats specific areas of the thermal paper as it scrolls by. The heated areas darken to create the image.

Paper

Thermal paper is chemically treated paper that changes color when heated. This makes the printout vulnerable to damage or degradation when exposed to heat.

Maintenance

Maintaining thermal printers is simpler than other types of printers. While print quality issues with thermal printers are mostly similar to inkjet and laser printers, excessively darkened or whole paper blackening is unique to thermal printers due to the heat-reactive nature of the paper. There are fewer moving parts and no ink. These are the main maintenance steps to know:

• Replace the paper.—Thermal paper comes in rolls of various sizes. Replacing the paper is a simple matter of removing the empty roll and inserting the new roll. There will be a button or wheel that will feed the paper into the printer after the new roll is inserted.

• Clean the heating element.—The heating element should be cleaned periodically to ensure proper heat transfer to the paper. Isopropyl alcohol is typically used as the cleaning agent. Some printers come with a pen or pad to make it easier to access the heating element for cleaning.

• Remove any debris.—Paper fragments and dust will accumulate in the printer over time. This debris should be removed as needed. A commonly used method is blowing out the debris with compressed air.

Impact

Impact printers use a matrix of pins to strike an ink ribbon to transfer ink to the paper. The most common type is the dot-matrix printer. A unique feature of impact printers, as compared to other printers, is that they can print multiple copies simultaneously using carbonless or no carbon required (NCR) paper.

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Impact printers have the following specific imaging parts:

• print head—The print head is a row or rectangular matrix of metal pins. The pins that strike the ink ribbon form the character to be printed.

• ribbon—The ribbon holds the ink that is transferred to the paper by the print head during printing.

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• tractor feed—The tractor feed feeds the paper through the printer.

Impact Paper

Impact paper is simply multipart paper made for impact printers. It may come on a roll or as fanfold paper in single-ply, duplicate, or triplicate. Duplicate and triplicate paper (NCR paper) transfers the image through to all copies simultaneously.

Maintenance

There is little maintenance required on impact printers. In most printers, these items can all be replaced by the user. Here are the maintenance steps you will need to know:

• Replace the ribbon.—Ribbon replacement is usually a simple task. The new ribbon should be taut, leaving no slack.

• Replace the print head.—The pins in a print head can get bent or broken, so the print head will eventually need to be replaced. The print head does get hot due to the friction of rapidly moving parts, so care must be taken to ensure it cools down before touching it. It is held in place by a lever that must be released to remove the old print head.

• Replace the paper.—Paper replacement requires a bit more effort than in other types of printers. The paper has holes along the side that are placed into the tractor feed. These must be aligned so that the paper feeds properly. Also, since the paper is continuous, as opposed to separate sheets, the top of the page must be lined up properly.