The encoder used in this printer consists of a disk, reflective sensor, and detection unit. The disk is installed on the motor shaft. The disk rotates as the motor does.

The disk has reflective areas and interrupting areas alternately located on its surface. The sensor strikes light to the rotating disk and sends the monitoring results

of the reflected light to the detection unit. The detection unit monitors the results constantly. It generates the two ENCODER DETECTION (ENCSNS1, ENCSNS2)

signals based on the tim-ing of detecting the reflective and interrupting areas on the disk and sends the signals to the DC controller.

Motor

shaft

2.6.2.6 Cooling Fan

The Cooling fan, a DC brushless motor with a built-in Hall device, cools off around the fixing unit, power supply unit, high-voltage power supply PCB, and car-

tridge.

The CPU (IC101) controls the cooling fan.

The CPU outputs the FAN DRIVE (FAN1D) signal after receiving a print command from the interface controller and rotates the cooling fan. After the completion

of a print operation, the CPU rotates the fan for a specified period based on internal temperature by monitoring the internal temperature detection thermistor (TH3).

Then it stops the fan.(Refer to the table below)

The CPU monitors the FAN LOCK DETECTION (/FAN1S) signal while the cooling fan is rotating. If the signal remains "H" continuously for more than 10 sec-

onds, the CPU determines a fan failure, then stops the printer engine, and notifies the failure to the interface controller.

Thermistor detection temparature (deg C)

44 or less

45 to 49

50 or more

2-40

Reflecting

areas

Interrupting

areas

Reflective

Sensor output