Potential Control; Overview; Copier/Printer Potential Control - Canon iR6570 series Service Manual

7.4 Potential Control

7.4.1 Overview

The machine uses the following functions and control mechanisms associated with its potential control system:

1. copier/printer potential control

2. APC (auto power control) correction
3. primary current determination (VD control)
4. laser output determination (VL control)
5. post-laser illumination potential measurement (VDC control)
The following shows the construction of the machine's control system associated with potential control:
The following signals are associated with potential control:
[1] POT-DT, drum surface potential measurement
[2] POT-ON, if '1', turns on the potential sensor
7.4.2 Copier/Printer Potential Control
The machine's potential control consists of copier potential control mechanisms and printer potential control mechanisms.
The machine uses VD=390V for both copier and printer control mechanisms.
The timing of potential control is as follows:
Purpose
Operating condition
Operation length
Service mode
Default
If enabled in service mode, potential control starts 10 min and 60 min after the main power switch is turned on or when the door is opened and closed. The
timing and particulars of potential control are as follows:
Laser output level determination
Control
signal
Primary charging wire
Control
Primary current determination
signal
J103
Developing bias (DC) determination
0V
B4
POT-DT [1]
B3
POT-ON
[2]
B2
24V
B1
At time of warm-up
to execute potential control for copier/printer mode
to determine a constant value for copier/printer mode
- the temperature of the fixing assembly is 50 deg C or lower
when the main power switch is on
- when the first image is being formed 60 min after warm-up
10 sec (approx.)
may be enabled or disabled using the following:
COPIER>OPTION>BODY>PO-CNT
ON (potential control for both copier and printer modes)
Developing cylinder
F-7-5
T-7-3
Laser light
Potential
sensor
J3
1
2
3
4
Chapter 7
0009-3538
0009-3540
7-5