2. LEARNING OBJECTIVES
1. Describe the various methods currently used to place computer print on
paper.
2. Discuss characteristics of dot-matrix characters.
3. Discuss the types of paper handling common to different printer
technologies.
4. Install and configure a printer for DOS or Windows operation.
5. List special considerations that must be observed when installing or
repairing serial printers.
6. Identify a given type of cable connection between the printer and the
computer.
7. Discuss data flow-control methods as they apply to serial printers.
8. Identify the major components of a dot matrix printer.
9. Describe troubleshooting techniques associated with dot-matrix printers.
10. Relate symptoms to associated components in a dot-matrix printer.
11. Describe general alignment procedures for printhead mechanisms.
12. Describe the operation of a typical ink jet-printer.
13. Identify the major components of an ink-jet printer.
14. Describe troubleshooting techniques associated with ink-jet printers.

3. 15. Relate symptoms to associated components in an ink-jet printer.
16. Describe the process for applying print to a page in a laser printer.
17. Identify the major components of a laser printer.
18. Describe troubleshooting techniques associated with laser printers.
19. Relate symptoms to associated components in a laser printer.

4. Figure 10-1: Typical Character Printer

5. Impact printers place characters on the page by causing a hammer device to strike an inked ribbon. The ribbon, in turn, strikes the printing surface (paper).

6. Figure 10-2: Fully-formed and Dot-Matrix Type Characters

7. Older non-impact printers relied on special heat-sensitive or chemically reactive paper to form characters on the page. Newer methods of non-impact printing use ink droplets, squirted from a jet-nozzle device or a combination of laser/xerographic print technologies, to place characters on a page.

8. Basically, two methods exist for creating characters on a page
Basically, two methods exist for creating characters on a page. One method produces a character that is fully shaped and fully filled-in. This type of character is called a fully-formed character. The other method involves placing dots on the page in strategic patterns to fool the eye into seeing a character. This type of character is referred to as a dot-matrix character.

9. Figure 10-3: The Daisy Wheel

10. Figure 10-4: Dot-Matrix Characters

11. Figure 10-5: Dot-Matrix Printer Pinheads

12. The term font refers to variations in the size and style of characters
The term font refers to variations in the size and style of characters. With true fully-formed characters, typically only one font is available unless you change the physical printing element. However, all other printing methods typically offer a wide variety of font types and sizes.
Three common classifications of character fonts exist: bit-mapped (or raster-scanned) fonts, vector-based fonts, and TrueType outline fonts.

13. Figure 10-6: True Type Enabling Window

14. Figure 10-7: Windows Character Map

15. Figure 10-8: Rotating Drum and Chain Printers

16. Two types of impact line printers exist:
Rotating drum printers
Chain (or band) printers

17. By the very nature of their operation, printers tend to be extremely mechanical peripherals. During the printing operation, the print mechanism must be properly positioned over each character cell in sequence.

18. Figure 10-9: Printhead Carriage

19. In addition to positioning the print mechanism for printing, all printer types must feed paper through the print area. The type of paper-handling mechanism in a printer is somewhat dependent upon two factors: it speed and the type of form intended to be used with the printer.

20. Figure 10-10: A Pin-Feed Tractor Mechanism

21. Two common methods exist for moving paper through the printer:
Friction-feed. Uses friction to hold the paper against the printer’s platen. The paper advances through the printer as the platen turns.
Pin-feed. Pulls the paper through the printer by a set of pins that fit into the holes along the edge of the form, as shown in Figure The pins may be an integral part of the platen or may be mounted on a separate, motor-driven tractor.

22. Figure 10-11: Common Printer Components

23. As with most other peripherals, the heart of a character printer is its interface/controller circuitry. The interface circuitry accepts data and instructions from the computer’s bus systems and provides the necessary interfacing (serial or parallel) between the computer, and the printer’s control circuitry.

24. In some printers, the microcontroller, RAM chips or modules, and ROM/EPROM devices may be treated as FRU components.

25. Generally speaking, one of the least difficult I/O devices to add to a microcomputer system is a parallel printer. This is largely due to the fact that, from the beginning of the PC era, a parallel printer has been one of the most standard pieces of equipment to add.

26. Serial printers are slightly more difficult to set up because the communication definition must be configured between the computer and the printer. The serial port must be configured for speed, parity type, character frame, and protocol.

27. Figure 10-12: Printer Installation Steps

28. As with mice, printers require device driver programs to oversee their operation.

29. Figure 10-13: Printer Driver Position

30. Serial printer problems basically fall into three categories:
Cabling problems
Configuration problems
Printer problems

31. Figure 10-14: Serial Printer Connection Schemes

32. Two popular methods of implementing software flow control are Xon/Xoff and ETX/ACK. In the Xon/Xoff method, special ASCII control characters are exchanged between the printer and the computer to turn the data flow on and off. In an ETX/ACK protocol, ASCII characters for End-of-Text (ETX) and ACKnowledge (ACK) are used to control the movement of data from the port to the printer.

33. Figure 10-15: Software Flow Control

34. Figure 10-16: Windows 3.11 Printer Installation Window

35. The components of a typical dot-matrix printer are depicted in Figure They consist of a power supply board, a main control board, a printhead assembly, a ribbon cartridge, a paper feed motor (along with its mechanical drive gears), and a printhead positioning motor and mechanisms.

36. Figure 10-17: Parts of a Dot-Matrix Printer

37. The control board is typically divided into four functional sections:
The interface circuitry
The character generation circuitry
The printer controller circuitry
Its motor control circuitry

38. Figure 10-18: Logical Parts of the Control Board

39. The status of the printer’s operation is monitored by the control board through a number of sensors:
Paper Out
Printhead Position
Home Position
(for the printhead carriage)

40. Operator panel information includes the following:
Online
Form feed
Line feed
Power/paper out

41. Figure 10-19: A Parallel Connection at the Printer

42. The printhead is a collection of print wires set in an electromagnetic head unit. The printhead assembly is made up of a permanent magnet, a group of electromagnets, and a housing. In the printhead, the permanent magnet keeps the wires pulled in until electromagnets are energized, causing them to move forward.

43. Figure 10-20: A Typical Dot-Matrix Printhead Control

44. Figure 10-21: Dot-Matrix Printhead

45. Figure 10-22: Installing a Tractor Assembly

46. The classical first step in determining the cause of any printer problem is to determine which part of the printer-related system is at fault: the host computer, the signal cable, or the printer.

47. The following are symptoms for dot-matrix printer problems:
No lights or noise from printer
Light or uneven print produced
Printhead moving but not printing
Dots missing from characters
Printhead printing, but does not move
Paper will not advance

48. Typical dot-matrix configuration information includes the following:
Printer mode
Perforation skip (for continuous forms)
Automatic line feed at the bottom of the page
Paper-handling type
ASCII character codes (7-bit or 8-bit)
Basic character sets

49. Other quantities that can be set up include the following:
Print font
Character pitch
Form length

50. Typical fonts included in dot-matrix printers are listed here:
Draft
Courier
Prestige
Bold prestige

51. Figure 10-23: Disassemble the Printer

52. Figure 10-24: The Printer Carriage

53. Paper is specified in terms of its Weight per 500 sheets at 22 inches by 17 inches (that is, 500 sheets of 22 inches by 17 inches, 21-pound bond paper weighs 21 pounds).

54. If the printhead does not operate, components involved can include the following:
The flexible signal cable between the control board and the printhead
The control board
Possibly the power supply board

55. Figure 10-25: Adjusting the Printhead Spacing

56. Figure 10-26: Printhead’s Timing Belt

57. Ink-jet printers produce characters by squirting a precisely controlled stream of ink drops onto the paper, as illustrated in Figure The drops must be controlled very precisely in terms of their aerodynamics, size, and shape, or the drop placement on the page becomes inexact and the print quality falters.

58. Figure 10-27: Ink-Jet Printers

59. The drops are formed by one of two methods:
Thermal shock heats the ink in a capillary tube, just behind the nozzle. This increases the pressure of the ink in the tube and causes it to explode through the opening.
Vibrations from a piezo-electric crystal force ink through a nozzle.

60. Figure 10-28: Drop-on-Demand Printing

61. Figure 10-29: Continuous-Stream Printing

62. The primary components of a typical ink-jet printer are listed here:
The printhead assembly
The power board
The control board
The printhead positioning motor and timing belt
The paper feed motor and gear train
The printer’s sensors

63. Figure 10-30: Ink-Jet Printer Components

64. Figure 10-31: Ink-Jet Paper Handling

65. As with the dot-matrix printer, the first step in determining the cause of an ink-jet printer problem is to determine which part of the printer system is at fault: the host computer, the signal cable, or the printer.

66. These are symptoms of ink-jet printer problems:
No lights or noise from printer
Light or uneven print produced
Printhead moving but not printing, or printing erratically
Lines on the page
Printhead printing, but does not move
Paper will not advance

67. Typical configuration information includes the following:
Page orientation (landscape or portrait)
Paper size
Collation
Print quality

68. You can also configure the basic appearance of color and grayscale images produced by the ink-jet printer. A color ink-jet printer uses four ink colors to produce color images: cyan, magenta, yellow, and black (referred to as CMYK color). To create other colors, the printer prints a predetermined percentage of the basic colors in proximity to each other.

69. Figure 10-32: Printer Case

70. The single item in an ink-jet printer that requires the most attention is the ink cartridge (or cartridges). As the ink cartridge empties, the printing eventually becomes faint and uneven, and the resolution of the print on the page diminishes.

71. Figure 10-33: Self-Contained, Snap-in Ink Cartridge

72. If the printer does not print during the self-tests, the components involved include the following:
The printhead
The flexible signal cable (between the control board and the printhead)
The control board
Possibly the power supply board

73. Figure 10-34: Printhead Positioning Components

74. The laser printer modulates a highly focused laser beam to produce CRT-like raster-scan images on a rotating drum, as depicted in Figure

75. Figure 10-35: A Typical Laser Printer

76. The six stages of operation in a laser printer include the following:
Cleaning
Conditioning
Writing
Developing
Transferring
Fusing

77. To accomplish these objectives, all laser printers possess the following logical blocks:
Power supply
Control board
Laser-writing unit
Drum unit
Fusing assembly
Paper feed motor and gear train
System’s sensors
Control panel board

78. Figure 10-36: Block Diagram of a Laser Printer

79. As the laser writes on the drum, that drum turns through the toner powder, which is attracted to the charged image on the drum.

80. Figure 10-37: The Developer Roller

81. Figure 10-38: Transfer Process

82. Figure 10-39: H-P Cartridge Configuration

83. Figure 10-40: Laser Printer Basic Components

84. A typical laser printer has sensors to determine what paper trays are installed, what size paper is in them, and whether the tray is empty. Sensors also track the movement of the paper through each stage of the printer. This means that the controller knows where the page is at all times and can sequence the activities of the solenoids and clutches properly.

85. Figure 10-41: Sensor Summary

86. Many of the problems encountered in laser printers are similar to those found in other printer types. For example, notice that most of the symptoms listed in the following section relate to the printer not printing, not printing correctly, and not moving paper through the printer.

87. Basically, paper jams occur in all three main sections of the printer:
The pickup area
The registration area
The fusing area

88. Unlike other printer types, the laser printer tends to have several high-voltage and high-temperature hazards inside it. To get the laser printer into a position where you can observe its operation, you must defeat some interlock sensors. This action places you in potential contact with the high-voltage, high-temperature areas mentioned above. Take great care when working inside the laser printer.

89. The following are symptoms of laser printer problems:
The printer is dead, power is on, but no printing occurs.
The print on the page is light or washed out.
A blank page is produced.
Stains or black dust appear on the paper.
Vertical lines appear on the paper.
The printer will not load paper.
The paper jams in the printer.
A paper jam has been cleared, and the unit still indicates a jam is present.

90. If the printer’s fans and lights are working, other components that are associated with a defective power supply include the following:
Main motor and gear train
High-voltage corona wires
Drum assembly
Fusing rollers

91. Four basic reasons can explain why the main motor may not run when the printer is supposed to print:
The portion of the power supply that supplies the motor is defective.
The control circuitry is not sending the enabling signals to turn on the motor.
The motor is dead.
The gear train is bound up and will not let the motor turn.

92. Normal print-delivery problems fall into eight categories:
Black pages
White (blank) pages
Faint print
Random specks on the page
Faulty print at regular intervals on the page
White lines along the page
Print missing from some portion of the page
Smudged print

93. Figure 10-42: Paper Tray Sensors

94. Figure 10-43: The Paper Path

95. Normally the system should be setup so that the following are true:
TTEnable=1
TTifCollisions=0
TTOnly=0

96. Figure 10-44: The Windows Printer Setup Window

97. KEY POINTS REVIEW
Impact printers place characters on the page by causing a hammer device to strike an inked ribbon. The ribbon, in turn, strikes the paper.

98. KEY POINTS REVIEW
Older non-impact printers relied on special heat-sensitive or chemically reactive paper to form characters on the page. Newer methods use ink droplets, squirted from a jet-nozzle device, or a combination of laser/xerographic print technologies to place characters on a page.

99. KEY POINTS REVIEW
Two basic methods exist for creating characters on a page. One method places a character that is fully shaped and fully filled-in on the page. This type of character is called a fully-formed character. The other method involves placing dots on the page in strategic patterns to fool the eye into seeing a character. This type of character is referred to as a dot-matrix character.

100. KEY POINTS REVIEW
The term font refers to variations in the size and style of characters. With true fully-formed characters, typically only one font is available unless you change the physical printing element. Three common categories of character fonts exist: bit-mapped (or raster-scanned) fonts, vector-based fonts, and TrueType outline fonts.

101. KEY POINTS REVIEW
By the very nature of their operation, printers tend to be extremely mechanical peripherals. During the printing operation, the print mechanism must be properly positioned over each character cell in sequence.

102. KEY POINTS REVIEW
In addition to positioning the print mechanism for printing, all printer types must feed paper through the print area. The type of paper-handling mechanism in a printer is somewhat dependent upon two considerations: its speed and the type of form intended to be used with the printer.

103. KEY POINTS REVIEW
As with most other peripherals, the heart of a character printer is the interface/controller that accepts data and instructions from the computer’s bus systems and provides the necessary interfacing between the computer and the printer’s control circuitry.

104. KEY POINTS REVIEW
In some printers, the microcontroller, RAM chips or modules, and the ROM/EPROM devices may be treated as FRU components.

105. KEY POINTS REVIEW
One of the least difficult I/O devices to add to a microcomputer system is a parallel printer. From the beginning of the PC era, the parallel printer has been one of the most standard pieces of equipment to add.

106. KEY POINTS REVIEW
Serial printers are slightly more difficult to set up because the communication definition must be configured between the computer and the printer. The serial port must be configured for speed, parity type, character frame, and protocol.

107. KEY POINTS REVIEW
As with mice, printers require device driver programs to oversee their operation.

108. KEY POINTS REVIEW
Two popular methods of implementing software flow control are Xon/Xoff and ETX/ACK. In the Xon/Xoff method, special ASCII control characters are exchanged between the printer and the computer to turn the data flow on and off.

109. KEY POINTS REVIEW
The components of a typical dot-matrix printer include a power supply board, a Main control board, a printhead assembly, a ribbon cartridge, a paper feed motor (along with its mechanical drive gears), and a printhead positioning motor and mechanisms.

110. KEY POINTS REVIEW
The printhead is a collection of print wires set in an electromagnetic head unit. The printhead assembly is made up of a permanent magnet, a group of electromagnets, and a housing.

111. KEY POINTS REVIEW
The first step in determining the cause of any printer problem is to isolate the part of the printer-related system at fault: the host computer, the signal cable, or the printer.

112. KEY POINTS REVIEW
Paper is specified in terms of its weight per 500 sheets at 22 inches by 17 inches (that is, 500 sheets of 22-by-17-inch, 21-pound bond paper weighs 21 pounds).

113. KEY POINTS REVIEW
Ink-jet printers produce characters by squirting a precisely controlled stream of ink drops onto the paper. The drops must be controlled very precisely in terms of their aerodynamics, size, and shape, or the drop placement on the page becomes inexact.

114. KEY POINTS REVIEW
A color ink-jet printer uses four ink colors to produce color images: cyan, magenta, yellow, and black (referred to as CMYK color). To create other colors, the printer prints a predetermined percentage of the basic colors in proximity to each other.

115. KEY POINTS REVIEW
The single item in an ink-jet printer that requires the most attention is the ink cartridge(s)

116. KEY POINTS REVIEW
The laser printer modulates a highly focused laser beam to produce CRT-like raster-scan images on a rotating drum.

117. KEY POINTS REVIEW
As the laser writes on the drum turns through the toner powder, which is attracted to the charged image on the drum.

118. KEY POINTS REVIEW
A typical laser printer has sensors to determine what paper trays are installed, what size paper is in them, and whether the tray is empty. The printer also uses sensors to track the movement of the paper through each stage of the printer.

119. KEY POINTS REVIEW
Many of the problems encountered in laser printers include the printer not printing, not printing correctly, and not moving paper.

120. KEY POINTS REVIEW
The laser printer tends to have several high-voltage and high-temperature hazards inside it. You may have to defeat some interlock sensors. This action places you in potential contact with the printer’s high-voltage, high-temperature areas. Take great care when working inside the laser printer.

121. REVIEW QUESTIONS 1
Referring to the Hardware Checks sections of the troubleshooting procedures for all three printer types, describe three general types of problems common to all printers. Describe the additional type of problem that dot-matrix and ink-jet printers have.

122. REVIEW QUESTIONS 2
What are the common transmission parameters that must be set up for a serial printer interface?

123. REVIEW QUESTIONS 3
Describe the purpose for using pin-feed mechanisms to move paper through the printer.

124. REVIEW QUESTIONS 4
Describe the reason for using tractor-feed paper handling.

125. REVIEW QUESTIONS 5
If the resolution of an ink-jet printer becomes unacceptable, what action should be taken?

126. REVIEW QUESTIONS 6
Describe the function of the fuser assembly in a laser printer.

127. REVIEW QUESTIONS 7
Describe the function of the primary corona (conditioning roller) in a laser printer.

128. REVIEW QUESTIONS 8
If a laser printer continues to show a paper jam problem after the paper has been cleared, what type of problem is indicated, and what action should be taken?

129. REVIEW QUESTIONS 9
List the three primary areas where paper jams occur in a laser printer, as well as any other areas where jams are likely to occur.

130. REVIEW QUESTIONS 10
Describe two methods used by ink-jet printers to put ink on the page.

131. REVIEW QUESTIONS 11
Does a successful self-test indicate that the printer is not the cause of the problem? List the parts of the system that can still be problem causes if the self-test runs successfully.

132. REVIEW QUESTIONS
How does a dot-matrix printer actually deliver ink to a page? 12

133. REVIEW QUESTIONS 13
What functions do the printer’s controller typically perform?

134. REVIEW QUESTIONS
List four things that can be damaging to the photosensitive surface of the laser printer’s drum. 14

135. MULTIPLE CHOICE QUESTIONS1
List three common pin configurations for dot-matrix printers.
a. 10, 20, and 30 pins
b. 5, 10, and 15 pins
c. 9, 18, and 24 pins
d. 3, 6, and 9 pins

136. MULTIPLE CHOICE QUESTIONS2
Name the four basic components of a laser printer cartridge.
a. Laser, toner supply, drum, and fuser
b. Toner supply, corona wire, drum
assembly, and developing roller
c. Laser, toner supply, corona wire, and
drum
d. Toner supply, corona wire, drum
assembly, and fuser

137. MULTIPLE CHOICE QUESTIONS3
What is the purpose of the primary corona wire in a laser printer?
a. It cleans the paper as it enters the printer.
b. It conditions the drum for printing.
c. It transfers toner from the drum to the paper.
d. It fuses the toner to the paper.

138. MULTIPLE CHOICE QUESTIONS4
What is the first action that should be taken, if the print generated by a dot-matrix printer becomes faded, or uneven?
a. Change the ribbon cartridge.
b. Add ink.
c. Adjust the print carriage.
d. Add toner.

139. MULTIPLE CHOICE QUESTIONS5
What is the first action that should be taken if the print generated by a laser printer becomes faded or uneven?
a. Adjust the contrast control.
b. Change the ink cartridge.
c. Check the toner cartridge.
d. Adjust the print mechanism.

140. MULTIPLE CHOICE QUESTIONS6
What type of electrical charge must be placed on the corona wire to transfer toner from the drum to the paper?
a. Negative
b. None
c. Neutral
d. Positive

141. MULTIPLE CHOICE QUESTIONS7
List the six stages of a typical laser printer.
a. Pick up, registration, transfer, printing,
fusing, and finishing
b. Pick up, conditioning, transfer, developing,
c. Cleaning, conditioning, writing, developing,
transferring, and fusing
d. Cleaning, registration, writing, transferring,

142. MULTIPLE CHOICE QUESTIONS8
List the fundamental parts of a dot-matrix printer.
a. Power supply, microprocessor, tractor feed
motor, printhead mechanism, and printhead
positioning motor
b. Power supply, interface board, paper feed
motor, printhead mechanism, printhead
positioning motor, and sensors
c. Interface board, ink cartridge, printhead
mechanism, printhead positioning motor, and
sensors
d. Controller, paper feed motor, ribbon cartridge,
and printhead positioning motor

143. MULTIPLE CHOICE QUESTIONS9
What type of ink delivery system is normally found in ink-jet printers built for the personal computers?
a. Drop-on-demand ink delivery
b. Continuous-stream ink delivery
c. Impact ink delivery
d. Compact-spray ink delivery

144. MULTIPLE CHOICE QUESTIONS10
Describe what the specification for 60-pound bond paper means.
a by-17-inch sheets weigh 60 pounds
b by-17-inch sheets weigh 60 pounds
c by-17-inch sheets weigh 60 pounds
d by-17-inch sheets weigh 60 pounds