Panasonic KX-FT76RU-B Service Manual ▷ View online
113
KX-FT76RU-B
5.4.4. SCANNING BLOCK
The scanning block of this device consists of a control circuit and a contact image sensor made up of a celfoc lens array, an LED
array, and photoelectric conversion elements.
array, and photoelectric conversion elements.
When an original is inserted and the start button pressed, pin 128 of IC1 goes to a high level and the transistor Q8 turns on and
pin 49 of IC1 goes to a low level and the transister Q22 turns on. This applies voltage to the LED array to light it and the voltage
(+5v) of CIS turns on. The contact image sensor is driven by each of the FTG-F1 signals output from IC1, and the original image
illuminated by the LED array undergoes photoelectric conversion to output an analog image signal. The analog image signal is
input to the system LSI (IC1) on AIN1 (pin 1 of IC1) and converted into 8-bit data by the A/D converter inside IC1. Then this signal
undergoes digital processing in order to obtain a high-quality image.
pin 49 of IC1 goes to a low level and the transister Q22 turns on. This applies voltage to the LED array to light it and the voltage
(+5v) of CIS turns on. The contact image sensor is driven by each of the FTG-F1 signals output from IC1, and the original image
illuminated by the LED array undergoes photoelectric conversion to output an analog image signal. The analog image signal is
input to the system LSI (IC1) on AIN1 (pin 1 of IC1) and converted into 8-bit data by the A/D converter inside IC1. Then this signal
undergoes digital processing in order to obtain a high-quality image.
114
KX-FT76RU-B
5.4.5. STEPPING MOTOR DRIVE CIRCUIT
1. Function
One individual stepping motor is used for transmission and reception. It feeds the document or recording paper synchronized
for reading or printing.
for reading or printing.
2. Circuit Operation
During motor drive, gate array IC1 pin 124 becomes a high level, and Q7 and Q5 go ON as a result. +24 V is supplied to the
motor coil.
Stepping pulses are output from gate array IC1, causing driver IC7 to go ON. The motor coil is energized sequentially in 2 phase
increments or 1-2 phase increments, which causes a 1-step rotation. A 1-step rotation is 0.13mm of recording paper or
document paper. The timing chart is below.
motor coil.
Stepping pulses are output from gate array IC1, causing driver IC7 to go ON. The motor coil is energized sequentially in 2 phase
increments or 1-2 phase increments, which causes a 1-step rotation. A 1-step rotation is 0.13mm of recording paper or
document paper. The timing chart is below.
Stepping Motor Phase Pattern
Function
Mode
Phase Pattern
Speed
Copy
Fine/Half Tone
1-2
217 pps
Super Fine
1-2
108.5 pps
FAX
STD
2
217 pps
Fine/Half Tone
1-2
217 pps
Super Fine
1-2
108.5 pps
———
Paper Feed
2-2
434 pps
When the motor is OFF, gate array IC1 pin 124 becomes a low level and Q7 and Q5 also turns OFF. Instead of +24V, +5V is
supplied through D3 so that the motor is held in place.
supplied through D3 so that the motor is held in place.
115
KX-FT76RU-B
5.4.6. GEAR SECTION
This section shows how the motor-driven gear mechanism works in the main operations: FAX transmission, FAX reception the
motor and copying.
motor and copying.
5.4.6.1. MODE SELECTION
When the motor attached to the Drive Motor Gear rotates counterclockwise (CCW), Swing Gear A-2 engages the CAM and the
CAM turns counterclockwise to select a mode. (See Fig. A.) There are three mode options controlled by the Switch: A:
Transmitmode, B: Receive mode and C: Copy mode. In Fig. B, you can see which mode is selected by the position of the rib in
the CAM.
CAM turns counterclockwise to select a mode. (See Fig. A.) There are three mode options controlled by the Switch: A:
Transmitmode, B: Receive mode and C: Copy mode. In Fig. B, you can see which mode is selected by the position of the rib in
the CAM.
116
KX-FT76RU-B
Click on the first or last page to see other KX-FT76RU-B service manuals if exist.