2.3.6 Printhead Drive Circuit
REV.-A
Figure 2-24 shows the printhead drive circuit in block diagram form. The print data already has been
expanded to create the image data. The CPU splits up this data three times and transfers this information
to the latch circuit in the
The CPU samples the voltage of the
V line via the A/D converter.
(See section 2.3.3.) The CPU outputs a pulse via the CPU time output port PPO. The length of this pulse
corresponds to the
V line voltage. This pulse becomes the head drive signal. In this way, PU4 135
outputs head drive signals (signals
to HD24) that relate to voltage levels through the
length of the pulses. These signals are output to the head for each of the sections of print data that
were created by dividing the data three times before sending it.
By sampling the
V line voltage and determining the length of the head drive signal, it is possible
to keep the energy supplied to the head constant. If the voltage of the
V line is HIGH, the CPU
shortens the output pulse. If the voltage of the
V line is LOW, the CPU lengthens the output pulse.
Figure 2-25 shows the timing of the head drive signal output.
E
HEAD 1-24
CPU
n
PU4135 (8
3 1 - 4 X 6
6
P r i n t h e a d
DATA LINE
I
R 7 4
1 %
Figure 2-24. Printhead Drive Circuit
I
1
I
I
output
Cl
I
-
-
-
-
-
-
-
-
-
-
-
- - - - - - - - - - -
I
I
I
L - - - - - - - - - - - J
Figure 2-25. Head Drive Signal Output Timing
2-21
Содержание LQ-1170
Страница 1: ...LQ 1170 24 PIN DOT MATRIX PRINTERS TM LQ8 1170 ...
Страница 2: ...L Q 8 7 0 1 1 7 0 SERVICE MANUAL EPSON T Printed on recycled paper ...
Страница 6: ...Revision Level Revision Date I 1st printing I 7 23 91 I I ViSC d I 10 g 91 I 1 2ndprhting I 3 17 92 I ...
Страница 20: ...REV A Table 1 9 Printing Bit Image Mode 80 136 Column dpi dots per inch ips inches per second 1 11 ...
Страница 101: ...10 9 91 Yes NO Replace pluggable chips on main board 5 6 ...
Страница 110: ...Table 5 4 Repair of the Power Supply Board Continued 5 15 ...
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Страница 136: ...Figure A 4 CO60 PSB Board Circuit Diagram A 12 ...
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Страница 141: ...REV A s XL r t RI FI IZSV SA 0 l Dl I N 0 I I D E C6 I I U J Figure A 9 CO60 PSB Board Component Layout A 1 7 ...
Страница 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 ...
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Страница 149: ...REV A A 5 CASE OUTLINE DRAWING Figure A l 4 1 Case Outline Drawing for LQ 870 A 25 ...
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