Canon iR5055, Service Manual

Page: 191 / 646

Chapter 7
7-7
F-7-11
7.4.6 APC Correction
0015-4484
iR5065 / iR 5055 / iR5075 / iR5075N / iR5065N / iR5055N
Changes in the laser output cause changes in the surface potential. To maintain a specific level of surface potential, the machine corrects the laser output control
value. The following shows the type and the particulars of laser output control value correction:
F-7-12
(1) Between-Sheet APC Control
Purpose: to maintain a specific level of surface potential without lowering the productivity during a continuous job; the machine measures the potential after
laser output between sheets, and corrects the laser output control value.
Timing: over the 1st interval between sheets every 1 min after the start of a continuous print job.
Potential measurement: the drum potential varies in drum peripheral direction; thus, the machine computes the average drum surface potential in drum
peripheral direction. It uses the result of computation to determine the laser output correction value. If measurement is not possible because of conditions
imposed by the need for measurement between sheets, the machine will continue measurement for an additional 1 min.
(2) Initial Rotation APC Control
Purpose: to make up for the changes in the VL potential of the laser output occurring after an appreciable time, the machine measures the drum potential and
corrects the laser output control value.
Timing: during initial rotation of the 1st job 60 min after the end of a job.
Potential measurement: the drum potential varies in peripheral direction, and the machine computes the average drum potential in peripheral direction. The
machine uses the result of computation to obtain the appropriate laser output correction value.
(3) Last Rotation APC Control
Purpose: when intermittent printing is repeated at short intervals, the absence of potential control can cause changes in the VL potential of the laser output.
To make up for the changes, the machine computes a correction value for the laser output control value and uses the result for the next job.
Timing: during last rotation for the 1st job 30 min after the most recent laser output correction.
Potential measurement: the drum potential varies in peripheral direction. The machine computes the average drum potential in peripheral direction, and
obtains the appropriate laser output correction value using the result of computation.
SERVICE MODE:
COPIER>OPTION>BODY>LAPS-SW (switching laser correction)
0: ON (left alone for 10 min -> initial rotation APC)
1: ON (left alone for 60 min -> initial rotation APC; default)
2: ON (left alone for 120 min -> initial rotation APC)
3: OFF only for initial rotation APC
4: OFF
7.4.7 Adjusting the Density in Various Modes
0015-4486
iR5065 / iR 5055 / iR5075 / iR5075N / iR5065N / iR5055N
The machine corrects the development bias determined as a result of potential control for the following operating modes, and uses the result as the target value for
the individual modes:
WMUPR WMUP
STBY
200 C
Potential sensor
Resulting
potential
Laser
Secondary
charging
VpcVpc
LP0
Vpc
Potential control sequence start
VD VL1
VL2
Vdc
VD
Vdc
Photosensitive
drum
Developing
cylinder
Potential sensor
Laser output
determined
Fixing assembly temperature 195 C
LP
Primary charging
current determined
Copier
potential
control
Printer
potential
control
Main power
switch ON
Fixing assembly temperature 195- C
(fixing assembly warm-up complete)
Control panel power switch ON
Start key ON
laser output
value correction
1 min later
1 min later
Continuous printing
Laser output
value correction