Main Elements; Printhead Driver Circuit - Epson Stylus Photo 720 Service Manual

EPSON Stylus Photo 720 / EPSON Stylus Photo EX3

2.2.2.1 Main elements

Table 2-8 shows the main elements on C301MAIN.
Table 2-8. Main Elements
IC Location Function
CPU 16bit CPU mounted on the MAIN board is driven by
IC1 (3.3V)
HD64F/2328F clock frequency 24MHz and controls the printer.
• Motor Control
• Head voltage control
• EEPROM control
Gate Array IC2
E05B70** (3.3V & 5.0V)
• Sensor supervise
• Timer IC supervise
• Parallel I/F, USB I/F control
• Capacity 4/8/16MB, Bus= 16 bit EEPROM
PROM IC3 (3.3V)
• Program or program + CG (Character generator)
RAM IC17 (3.3V) Bus= 16 bit, 4Mbit DRAM
2kbit EEPROM
AT93C56 IC6 (5.0V) • Default value setting
• Parameter backup
Reset/ Timer IC
• For +5V; reset when +4.3V is detected
RTC-9810SA IC5 (5.0V)
• For +42V, reset when +35.5 is detected
• Timer function is attached powered by lithium
74V161284 IC9 (5V) IEEE1284 parallel I/F transceiver IC
PDIUSBP11A IC10 (3.3V) USB Rev1 transceiver
LB11847 IC13 CR motor drive IC
LB11847 IC14 PF/ PUMP/ ASF motor drive IC
Head drive control HIC
CXA2128S IC15
• Generates head common voltage.

2.2.2.2 Printhead Driver Circuit

The printhead driver circuit consists of the following two components:
Operating Principles
battery.
Electrical Circuit Operating Principles
Head common driver circuit
n
(Common driver IC15 & Wave amplifier transistor Q2, 3)
Nozzle selector IC on the printhead driver board.
n
The common driver (IC15) generates a reference drive waveform according to the
output signals from the ASIC (IC2). The reference drive waveform is amplified by the
transistors Q2 and Q3 and then transferred to the nozzle selector IC on the head board.
Print data is converted to serial data by the ASIC and then sent to the nozzle selector IC
on the head 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
produced by the common driver. See Figure 2-14 for the printhead driver circuit block
diagram.
Revision A
45