Canon imagePRESS C1 Service Manual - page 374
Chapter 7
7-25
F-7-25
[1] Detection result of the patch image read sensor
[2] Detection result of the ATR sensor
PS7: ATR sensor
PS3: Patch image read sensor
DC-CON: DC controller
MN-CON: Main controller
7.4.11 D-max Control
0020-4149
imagePRESS C1+ (Printer) / imagePRESS C1+
This D-max control (image density correction control) is executed to control the variation in image density caused by the change in environment, or deterioration
of the photosensitive drum or toner.
Activation Timing
- At PASCAL control
- At every paper interval
Control Description
The DC controller creates patch patterns of each color (L, Y, M, C, Bk) on the drum at every paper interval. Afterwards, the patch image read sensor (PS3) measures
the patch patterns to execute toner supply control according to patch density. At this point, the ATR sensor (PS7) reads the sleeve surface of the developing assembly
to measure the T/D ratio. The DC controller evaluates whether to execute toner supply by measuring result of the T/D ratio to determine the developing bias and
the grid bias for each color (L, Y, M, C, Bk) in order to realize optimal density.
Memo:
T-7-12
Condition
Cause
Remedy
The patch density is light, and the
sleeve surface is dark
The toner density developed to the drum is getting
lower due to developing-related reasons,
Stop toner supply, and determine the developing bias and the grid bias in
order to obtain optimal density.
DC-CON
MN-CON
PS7
[2]
PS3
[1]
Y
M
C
K