Chapter 11

Printers

You Will Learn…• How printers work and how to troubleshoot

them

Printers• Local printers connect directly to computer via

parallel port, serial port, USB port, infrared connection, wireless connection, IEEE 1394 port, SCSI port, or PC Card connection

• Network printers are accessed over the network

Main Types of Printers• Laser

• Ink-jet

• Dot-matrix

• Thermal printers and solid ink printers

Laser Printers• Use electrophotographic

process

• Range from small, personal desktop models to large network printers capable of handling and printing large volumes continuously

• Require interaction of mechanical, electrical, and optical technologies

How a Laser Printer Works• Places toner on electrically charged rotating

drum

• Deposits toner on paper as paper moves through the system at same speed the drum is turning

Six Steps of Laser Printing1. Cleaning

2. Conditioning

3. Writing

4. Developing

5. Transferring

6. Fusing

• Take place inside toner cartridge

• Use components that undergo the most wear

Six Steps of Laser Printing

Step 1: Cleaning

Step 2: Conditioning• Conditions drum to contain a high electrical

charge

Step 3: Writing• Laser beam discharges a lower charge to only

those places where toner is to go

Step 3: Writing• Data from PC is received by formatter (1) and passed

to DC controller (2) which controls laser unit (3)

• Scanning mirror (4) is turned clockwise by scanning motor

• Laser beam is reflected off scanning mirror, focused by focusing lens (5) and sent to the mirror (6)

• Mirror deflects laser beam to a slit in the removable cartridge and on to the drum (7)

Step 3: Writing

Step 4: Developing• Toner is placed onto the drum where the

charge has been reduced

Step 4: Developing

Step 5: Transferring• Strong electrical charge draws toner off drum

onto paper; takes place outside the cartridge

Step 6: Fusing• Heat and pressure fuse toner to paper

Ink-Jet Printers• Small

• Print color inexpensively

• Tend to smudge on inexpensive paper

• Slower than lasers

How an Ink-Jet Printer Works• Print head moves across paper, creating one

line of text with each pass

• Shoots ionized ink at a sheet of paper in a matrix of small dots

• Several technologies are used to form ink droplets (eg, bubble-jet)

• Uses ink cartridges

Ink-Jet Cartridges

Photo-Quality Ink-Jet Printers• New generation of ink-jet printers that give

photo-quality results

• Mix different colors of ink to produce a new color that then makes a single dot

Dot-Matrix Printers• Less expensive; lesser quality

• Impact printer; can print multicopy documents

• Print head moves across width of the paper, using pins to print a matrix of dots on the page

• Uses a ribbon

• If print head fails, buy a new printer

Dot-Matrix Printers

Thermal Printers andSolid Ink Printers

• Relatively new printer technologies

• Non-impact printers that use heat to produce printed output

Thermal Printers• Use wax-based ink that is heated by heat pins that

melt ink onto paper

• Internal logic of the printer determines which pins get heated in order to produce the printed image

• Popular in retail applications for printing bar codes and price tags

• Can burn dots onto special paper or use a ribbon that contains wax-based ink

Solid Ink Printers• Store ink in solid blocks that are easy to

handle; several can be inserted in printer to be used as needed

• Solid ink is melted into the print head which spans the width of the paper

• Head jets the liquid ink onto the paper as it passes by on a drum

Solid Ink Printers• Advantages

Simple design Excellent print quality Easy to set up and maintain

• Disadvantage Time it takes (~15 minutes) for the print head to

heat up

Printer Manufacturers

Installing a Local Printer• Physically attach printer to computer (via parallel,

serial, USB, SCSI, IEEE 1394 port; PC Card or Infrared connection; or wireless access point)

• Install printer drivers Have Windows do it Use printer manufacturer’s installation program (best way)

• Alternately, use Windows Printer window to install

• Test the printer

Installing a Network Printer• Network printer contains a NIC and connects

directly to the network or is shared on the network by another PC

• Can use Network Neighborhood or My Network Places to install a network printer on a remote PC

Troubleshooting Guidelinesfor Printers

• Printer maintenance

• General printer troubleshooting

• Problems with laser printers

• Problems with ink-jet printers

• Problems with dot-matrix printers

Printer Maintenance• Procedures vary widely from manufacturer to

manufacturer and printer to printer

• Make sure consumables for the printer are on hand

• Research printer documentation or manufacturer’s Web site for specific maintenance tips

• Clean inside and outside of the printer

General Printer Troubleshooting• Isolate the problem

Application attempting to use the printer

OS and printer drivers Connectivity between PC

and printer Printer itself

Addressing Printer Problems Caused by Hardware

• Verify a printer self-page can print

• Problem with printer cable

Problems with Laser Printers• Poor print quality due to low toner

• Printer stays in warm-up mode

• Paper Jam or Paper Out message is displayed

• Printer images are distorted

• Printing is slow

• A portion of the page does not print

Problems with Ink-Jet Printers• Print quality is poor

• Printing is intermittent or absent

• Lines or dots are missing from the printed page

• Ink streaks appear on the printed page

To Clean Ink-Jet Nozzles

Problems with Dot-Matrix Printers• Print quality is poor

• Print head moves back and forth, but nothing prints

Chapter Summary• Printers and how to support them