Controlling Primary Charging; Outline - Canon iR5000i Service Manual

3.2 Controlling Primary Charging

3.2.1 Outline

The primary charging control system serves the following functions:
1. Turning on/off the primary corona current.
2. Controlling the primary corona current to a specific level.
3. Controlling the grid bias to a specific level (fixed to 850 V by varistor).
The system used to control primary charging is constructed as follows:
J102A
1
2
3
PR-LEAK-DETECT [1]
4
5
6
7
8
9
10
PR-CNT [2]
11
12
13
14
15
PR/TR-REMOTE [3]
16
The following signals are used:
[1] primary charging leakage detection signal; '0' upon detection of an excessively high or
low level of current.
[2] primary corona current control signal; the output of the primary corona current turns
ON when the voltage is about 3 V or higher or lower than 11 V; it turns OFF when the
level is about 12 V or higher.
[3] high-voltage remote signal; turns on/off the output of primary corona current.
COPYRIGHT © 2001 CANON INC.
J4502
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
F04-302-01
2000 2000 2000 2000 CANON iR5000i/iR6000i REV.0 JUNE 2001
CHAPTER 4 IMAGE FORMATION SYSTEM
The primary charging bias
changes as follows in keeping
with the potential of HV-PR.
1400µA
600µA
T4506
J4507
3V 11V12V
HV-PR
Primary charging wire
Grid wire
4-19 P