Epson STYLUS COLOR 480, Руководство по обслуживанию

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EPSON Stylus COLOR 480 Revision B
Operating Principles Electrical Circuit Operating Principles 47
2.2.2.2 Printhead Driver Circuit
The printhead drive circuit consists of the following two components:
n
Head common driver circuit
(Common driver IC7 & Wave amplifier transistor Q1, Q2)
n
Nozzle selector IC on the printhead driver board.
The common driver (IC7) generates a reference drive waveform according to the
output signals from the CPU (IC1). The reference drive waveform is amplified by the
transistors Q1 and Q2 and then transferred to the nozzle selector IC on the printhead
circuit board. Print data is converted to serial data by the CPU and then sent to the
nozzle selector IC on the printhead circuit board. Based on the serial data, the nozzle
selector IC determines the nozzles to be actuated. The selected nozzles are driven by
the drive waveforms generated by the common driver. See Figure 2-19 for the
printhead driver circuit block diagram.
Figure 2-19. Printhead Driver Circuit
o
Head common driver circuit
The reference head drive waveform is generated in the common driver (IC7) based
on the following 11 signal lines output from the CPU (IC1); A0-A3, CLK1, CLK2,
FLOOR, RST, DATA, DCLK, and E.
Based on the DATA signal output from the CPU (IC1), the original data for the
head drive waveform is written in the memory in the common driver (IC7).
The addresses for the written data are determined by the A0 - A3 signals, and, of
among, data used to determine the waveform angles is selected and appropriate
head driver waveform is generated. Generated head drive waveform is transferred
to nozzle selector IC on the head driver board and applied to the nozzle PZT
specified by nozzle selector IC.
o
Head nozzle selector circuit
Printing data are allocated to the two rows, the number of the head nozzle rows,
and converted into serial data by the CPU (IC1). Then the converted data is
transferred to the nozzle selector IC through the two signal lines (SI0 to SI2).
Data transmission from the CPU to the nozzle selector synchronizes with the SCK
clock signal and the LAT signal. Referring to the transferred data, nozzles to be
activated are selected, and the PZTs of the selected nozzles are driven by the drive
waveform output from the head common driver.
H e a d D r i v e
P u l s e
A O
A 1
A 2
A 3
C L K 1
C L K 2
F L O O R
R S T
D A T A
D C L K
E
V C C 4 5
V C C 4 5 _ 2
N P N B
P N P B
F B
I C 7
C o m m o m
D r i v e r I C
N o z z l e S e l e c o r I C
I R 2 C 9 6 F
F 1
+ 4 2 V
+ 5 V
L A T
S I 1
S I 2
S C K
N C H G
C H
S P
T H M
V D D
V H V
C O M
G N D 2
G N D
G N D
G N D
G N D
1 3
1 6
1 5
3
5
7
9
1 4
4
1 2
1 0
6
5
2
1 1
1
C N 4
H C H
H S P
A N 0
H S 0 1
H S 0 2
H C L K
H N C H G
H W A 0
H W A 1
H W A 2
H W A 3
H W C L K 1
H W C L K 2
H W F L R
H W R S T
H W S D A T A
H W S C L K
H W S L A T
I C 1
E 0 1 A 1 4 N A
H W L A T
2 2
2 3
2 0
1 8
1 6
2 8
2 7
2 6
2 5
4 7
4 6
4 5
4 3
4 0
3 9
3 8
3 7
4 8
4 9
4 1
3
4
5
6
2 9
3 0
1
2 5
3 0
2 8
2 7
2 6
2 4
2 9
2 2