REV.-A
2.1 PRINTER MECHANISM OPERATION
This section describes the Model 5D
printer mechanism and explains how it works. The Model
5D 1
printer mechanism features a
impact dot printhead for serial printing. The printer
mechanism has four main parts: the printhead mechanism, the carriage movement mechanism, the paper
advance mechanism, and the ribbon advance mechanism. The following sections describe these parts.
2.1.1 Printhead Mechanism
The printhead mechanism consists of the printhead itself, the ink ribbon, and the platen. The printhead
contains 24 wires in a zigzag arrangement in two rows of 12. A drive coil is provided for each of these
wires to make the wires move in and out of the printhead and print dots independently of each other.
The four steps below describe the basic way that the wires are driven.
1. The control circuit outputs the drive signal to the printhead drive circuit. This changes the printhead
drive voltage and current flows through the corresponding printhead coil. The coil acts as a solenoid
and generates a magnetic force.
2. This induced force causes the plate to approach the coil rod and the associated dot wire is rapidly
ejected to impact on the platen.
3. The dot wire presses the ink ribbon up against the paper as it hits the platen and, in this way, prints
a dot on the paper.
4. As soon as the current through the coil is switched off, the force induced in the coil rod stops. The
plate then returns to its original position (its position before the coil was energized) through the action
of the plate spring. After the dot wire hits the platen, the rebounding force of hitting the platen works
with the wire return spring to pull the wire back to its original position in relation to the plate.
Platen
Dot Wire
Ribbon Mask
Wire Resetting Spring
Plate Spring
Figure 2-l. How the Printhead Works
Figure 2-l shows how the printer mechanism prints a single dot.
The printhead tends to heat up after a period of continuous printing. To minimize the possibility of the
dot wire drive coils in the printhead overheating and causing a loss of performance, the printhead is
equipped with a thermistor that detects the temperature of the printhead. When this thermistor detects
changes in the printhead temperature, the voltage signal changes. The control circuit reads this signal
change for feedback control.
2-1
Summary of Contents for LQ-1170
Page 1: ...LQ 1170 24 PIN DOT MATRIX PRINTERS TM LQ8 1170 ...
Page 2: ...L Q 8 7 0 1 1 7 0 SERVICE MANUAL EPSON T Printed on recycled paper ...
Page 101: ...10 9 91 Yes NO Replace pluggable chips on main board 5 6 ...
Page 110: ...Table 5 4 Repair of the Power Supply Board Continued 5 15 ...
Page 118: ......
Page 121: ...REV A Figure 6 2 LQ 870 Lubrication Points 6 3 ...
Page 122: ...REV A Figure 6 3 LQ 1170 Lubrication Points 6 4 ...
Page 134: ...1 I II ...
Page 135: ...REV A Q m u D w IL 0 1 xl Figure A 3 CO60 DRV Board Circuit Diagram A 11 ...
Page 136: ...Figure A 4 CO60 PSB Board Circuit Diagram A 12 ...
Page 138: ...LO SLOE002 OWO9 1Nd 0 9 0 3 5 f l P I 11 I 01 I 6 I 8 1 L 9 I 9 I B I I2 I 2 I 1 ...
Page 142: ...REV A Fl 24ov T3 IsA I I II II AL I CU rl Figure A 10 C060 PSE Board Component Layout A 1 8 ...
Page 143: ...LMS d10 IP IMS dla ...
Page 144: ...REV A A 4 EXPLODED DIAGRAM Figure A l 2 1 Exploded Diagram for LQ 870 A 2 0 ...
Page 145: ......
Page 146: ...REV A Figure A 13 1 Exploded Diagram for Model 5DlO A 22 ...
Page 147: ... 5 2 5 610 c 3 5 9 0 El ...
Page 149: ...REV A A 5 CASE OUTLINE DRAWING Figure A l 4 1 Case Outline Drawing for LQ 870 A 25 ...
Page 151: ...lllllll IllI l l IIIIII II0 IIll III1 I I I C O 6 1 M A I N B o a r d A 3 7 ...
Page 152: ... U nRonenl2 i i C O 6 0 HAIN B t _1 m r OL J IIA IS I 19 CNI 36 I I8 I 23 IS ...
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