EPSON Stylus PHOTO 810/820/830

Revision B

2.2.2.2 Printhead Driver Circuit

The printhead driver circuit consists of the following two components:

„Head common driver circuit (Common driver IC19 & Wave amplifier transistor Q2, Q3)

„Nozzle selector IC on the printhead driver

The common driver (IC19) generates a basic drive waveform according to the output signals from CPU (IC1). The basic drive waveform is amplified by the transistors Q2 and Q3 (the amplified one is called drive waveform.) and then transferred to the nozzle selector IC on the printhead driver board. Print data is converted to serial data by the CPU and then sent to the nozzle selector IC on the printhead driver 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 amplified by the transistor Q2 and Q3. See refer to Figure 2-19for the printhead driver circuit block diagram.

† Head common driver circuit

The basic drive waveform is generated in the common driver (IC19) based on the

following 12 signal lines output from the CPU (IC1); A0-A4, CLK1, CLK2,

FLOOR, RST, DATA, DCLK, and E.

By the DATA signal output from the CPU, the original data for the basic drive

waveform is written in the memory in the common driver (IC19). The addresses

for the written data are determined by A0-A4 signals. Then, the necessary data is

selected from the address and appropriate basic drive waveform is generated.

Generated basic drive waveform is transferred to nozzle selector IC on the

printhead driver board through the transistor Q2 and Q3 and applied to the nozzle

PZT specified by nozzle selector IC.

† Nozzle selector circuit

Printing data is allocated to the six rows (the number of the head nozzle rows) and

converted into serial data by the CPU (IC1). Then the converted data is transferred

CPU (IC1)

HWA0

HWA1

HWA2

HWA3

HWA4

HWCLK1

HWCLK2

HWFLR

HWRST HWSDATA HWSCLK HWSLAT HSOCLK HCH HSO1 ~ HSO6

HSOCMD HLAT HNCHG C-P32 C-P13 C-P30 C-P34 C-P12 C-P40

 

 

Common

 

+4.2V

+3.3V

Nozzle

 

 

 

 

 

 

 

Driver(IC19)

 

 

 

Selector IC

 

 

 

 

19

F1

 

132

26

AO

VCC45

15

COM

 

 

 

133

25

A1

 

 

 

13

COM

134

24

A2

NPNB

17

Q2

 

 

135

23

A3

15

 

 

136

22

A4

PNPBFB

14

Q3

 

 

127

3

CLK1

 

 

 

CN9

 

126

4

CLK2

 

 

 

 

 

1255 FLOOR

124

6

 

RST

 

 

 

 

 

 

11

SCK

 

 

 

 

 

 

 

130

27

 

DATA

 

 

 

 

 

 

9

CH

129

28

 

DCLK

 

 

 

 

 

 

2

SI1 ~ SI6

128

1

 

E

 

 

 

 

 

 

1

SP

 

 

 

 

 

 

 

13

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

12

 

 

 

 

 

 

 

 

 

 

 

 

 

 

21

 

 

 

 

 

 

 

 

 

 

 

 

2

COM

 

 

 

 

 

 

 

 

 

 

 

 

24

 

 

 

 

 

 

 

 

 

 

 

 

4

 

 

 

 

 

 

 

 

 

 

 

 

VHV

19

 

 

 

 

 

 

 

 

 

 

 

 

8

 

 

 

 

 

 

 

 

 

 

 

 

LAT

20

 

 

 

 

 

 

 

 

 

 

 

6

 

 

 

 

 

 

 

 

 

 

 

 

NCHG

8

 

 

 

 

 

 

 

 

 

 

 

 

10

 

 

 

 

 

 

 

 

 

 

 

 

CSCK

11

 

 

 

 

 

 

 

 

 

 

CN8

 

11

 

 

 

 

 

 

 

 

 

 

 

COI

10

 

 

 

 

 

 

 

 

 

 

 

12

 

 

 

 

 

 

 

 

 

 

 

 

CRST

18

 

 

 

 

 

 

 

 

 

 

 

14

 

 

 

 

 

 

 

 

 

 

 

 

CSDA

9

 

 

 

 

 

 

 

 

 

 

 

15

 

 

 

 

 

 

 

 

 

 

 

 

CVDD

6

 

 

 

 

 

 

 

 

 

 

 

 

13

 

 

 

 

 

 

 

 

 

 

 

 

THM

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Head

Drive

Pulse

to the nozzle selector IC through the six signals lines (HS01 to HS06). Data

transmission from the CPU to the nozzle selector synchronizes with the LAT

signal and SCK clock signal. Based on the transmitted data, appropriate nozzle is

selected and the PZTs of the selected nozzle are driven by the drive waveform

output from the head common driver.

Figure 2-19. Printhead driver circuit

Operating Principles

Electrical Circuit Operating Principles

49