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The scanning block of this device consists of a control circuit and a CIS (contact image sensor), and AFE (Analog Front End)
include A/D Converter.

When an original document is inserted and the start button pressed, pin A3 of IC300 goes to a high level and the transistor Q524
and Q517 turns on. This applies voltage to the CIS. The CIS is driven by each of the CCDSH, CCDCLK signals output from IC300,
and the original image illuminated by the LED to output an analog image signal. 
The analog image signal is input to the AFE on VINP(20pin of IC503) and converted into 16-bit data by the A/D converter inside
IC503. Then this signal undergoes digital processing in order to obtain a high-quality image.

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1. Functions

This motor functions for main operations FAX reception and copy printing.
This feed recording paper synchronized for printing.

2. Motor operation

Excitation pulses is output from IC300 pins A12, D12, B12 and C12. Then stepping pulses are output from driver IC (IC504)
pin No 16, 18, 19 and 21, and drives the motor coil.
During motor driving, pin K24 of IC300 becomes a high level.
As a result, a current of about 1A are supplied to the motor coil.

FUNCTION

MODE

PHASE PATTERN

SPEED

CURRENT

PRINT

plain paper

2 phase

951pps

1A

PRINT

envelope

2 phase

475pps

0.8A

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General

Engine motor drive circuit is consist of motor current control circuit and engine motor driver.

1. Circuit explanation

According to the print speed, each motor current is controlled for appropriate value.
When print speed is low, motor current is reduced to prevent the vibration during motor rotation. 
When print speed is high, motor needs much driving force. so much current should be supplied.

For the control of motor current, Vref voltage of each motor driver is controlled.
When Vref voltage is high, motor current is increased, and the voltage is low, motor current is reduced.
In order to control Vref voltage, PWM pulse is supplied from IC300 pin B8.
PWM pulse is inverted by Q528 and integrated by R533, R534, and C562, then convert to DC voltage.

This DC voltage is divided by R595, R597and R598, then input into Vref pin of motor driver.
When duty of PWM pulse is high, Vref voltage is decreased and when duty is low, Vref voltage is increased.

Engine motor current is controlled approx. 0.8A-1A (ADF equipped model only).

2. Circuit diagram

3. Timing chart

Following timing charts are the example when PWM pulse duty are approx 10% and 30%.