EPSON Stylus PHOTO 810/820/830

Revision B

2.2.3.6 Sensor Circuit

:

CPU (IC8) on the Main board monitors the status of the printer by several sensors.

 

However, unlike the previous product, ASF unit on these printers does not have ASF

 

sensor. Instead of ASF sensor, Change lever and the Clutch mechanism is used to

 

detect ASF home position. (As for the ASF home position detection, refer to 2.1.4.)

 

†HP/PE sensor

HP/PE sensor uses photo interrupter method and always monitors the two status during the printer is in the power on status.

The photo interrupt component and two detection levers consists of this sensor.

„CR home position

The CR home position is detected on the right edge of the CR shaft with the HP/PE sensor during the variety sequence. In case that the CR home position is detected, this sensor outputs HIGH signal to the CPU (IC8).

If CR home position is not detected in the detection position correctly, this sensor outputs LOW signal to CPU and the printer indicates the error (As for the error indication, refer to 1.4.3.)

„Paper top & end position

When the Paper is in the paper path during the paper loading/feeding sequence, HP/PE sensor outputs the HIGH signal.

When the Paper is not in the paper path, this sensor outputs the LOW signal and the printer indicates the error (As for the error indication, refer to 1.4.3.)

†Thermistor (THM)

The thermistor is directly mounted on the printhead driver board. It monitors the temperature around the printhead and determines the proper head drive voltage to uniform the weight of the ink fired from printhead. This information is fed back to the CPU analog port. When the temperature rises, the head drive circuit lowers the drive voltage: When the temperature lowers, the head drive circuit rises the drive voltage.

The block diagram for the sensor circuit is shown below.

IC8

 

 

E01A37CB

SENV

 

+3.3V

 

 

3

 

+3.3V

GND

CN4

C-P15

2

HP/PE Sensor

HP

 

130

1

 

 

GND

CN8

 

 

Head FFC

C-P40 33

13

 

THM

 

Figure 2-30. Sensor circuit diagram

Operating Principles

Electrical Circuit Operating Principles

58