Epson 4003353 User Manual

Page 46

Principles

Sty/us

2.3.2.1 Reset Circuits

The

MAIN board

contains

2 reset circuits: the

monitor reset circuit and the

monitor

reset circuit. The

monitor reset circuit monitors the voltage

of the

using reset

and outputs a reset signal to the

gate array

when the voltage level

drops below

The

monitor reset

monitors the

voltage level of the

line,

using reset M51955B

and outputs a reset signal to the CPU.

reset signal is generated

when the voltage level drops

below

and this causes a

interrupt (NM).

CPU

(ICI)

M51 9556

‘6

PA8

RES

Figure 2-19. Reset

2.3.2.2 Sensor Circuits

RST

Type B

Circuit Block Diagram

‘. .,-

The following sensor circuits enable the

MAW board to monitor printer mechanism status:

HP sensor

HP (home position) sensor is

to the

of the

printer mechanism to detect the carriage home position. A LOW level from the
signal indicates that the carriage is m home position.

PE sensor A mechanical switch PE (paper end) sensor is built into the printer

mechanism to

determine whether there is paper in the printer or not.

A LOW

level

the

signal

indicates that no paper is loaded.

CO sensor

A micro switch is attached to the bottom of each ink cartridge holder in the carriage
unit. When the ink cartridge is installed, these switches are pressed and a LOW
level from the signal

that the ink cartridge is installed into the ink

cartridge holder.

Thermistor

A thermistor is attached to the color

printhead

driver board to monitor its

temperature. The

CPU changes the

drive signal’s pulse width (charge

pulse width) based on the temperature level.

CPU (lCl)

[

“

AN1

AN2

AN5

●

“

cco-

[

“

ANO

AN4

4 “ 70

Figure 2“20.

Sensor Circuit Block Diagram

2-16

Rev. A