Mechanism - Canon NP6320 Service Manual

CHAPTER 4 IMAGE FORMATION SYSTEM
B.

Mechanism

1. Turning the Scanning Lamp ON and OFF
The microprocessor (Q303) on the DC controller PCB controls the lamp driver. The scanning
lamp goes ON when the scanning LAMP ON command (LAON) is '1', and it goes OFF when the
signal is '0'.
2. Controlling the Intensity of the Scanning Lamp
The intensity of the scanning lamp is controlled by VR202 on the lamp driver PCB.
During AE exposure, however, a voltage (135 V) is applied to the scanning lamp.
The adjustment of the copy density using its development bias; see p. 4-8.
3. Error Protection
The condition of the scanning lamp is monitored using the lamp check signal.
If the lamp check signal is received by the DC controller even when the lamp is off, the error
detection circuit generates the AC SHUTOFF signal to force the relay (K101) on the power supply
PCB to go OFF, thereby cutting the power supply assembly; also, PW_ON_OFF signal is sent to
the main switch. In this case, E220 error is displayed.
4. Zero-Cross Signal
The board generates the zero cross signal that the DC controller uses to control the fixing
heater temperature. E261 is indicated on the control panel if an zero cross error is identified.
PW_ON_OFF
J313-7
DC controller PCB
4-4
COPYRIGHT © 1999 CANON INC.
J306
-4
MEAT
J305 J203
-3 -4
Lamp ON
LAMP
detection
CHECK
circuit
ZERO
CROSS
J305
J203
-2
-5
Intensity
J305 J203
switching
-1 -6
circuit
LAMP
SHIFT
J305 J203
-4 -3 Switching
circuit
LAMP-ON
Triac-triggering circuit
Lamp driver unit
Figure 4-201
Power supply assembly
J201
-1
-2
J202-1
Scanning lamp
Phase
control
J202-3
Short connector
CANON NP6320 REV.0 DEC. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
K101
SW1
FU2
(LA1)