D-Half Control - Canon imagePRESS C1 P Service Manual

Chapter 7
The patch density is dark, and the
sleeve surface is light
[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

7.4.12 D-half Control

imagePRESS C1 P / imagePRESS C1
This control regulates gradation correction in the main controller of the printer in order to achieve optimum gradation characteristics.
Start-Up Timing
- While performing the PASCAL control
- During last rotation after 500 printing jobs (When the full-color prints)
- During initial multiple rotation at power-on (The fixing temperature must be 50 deg C or lower.)
Description
Main controller outputs the patch data of each color (Y, M, C, Bk) at the DC controller when given conditions are met. DC controller produces patch patterns of
each color (Y, M, C, Bk) on the drum based on this data.
Subsequently DC controller measures patch patterns with the patch image scan sensor (PS3, PS4, PS76) and sends the results back to the main controller. Based on
the obtained measurements, main controller then regulates the gradation correction in order to achieve optimal halftone image/
This control also produces a standard patch used in the ARCDAT control and stores a set of standard data for the AR CDAT collected from PS3, PS4, PS76.
(See Note.)
7-26
The toner density developed to the drum is getting
higher due to developing-related reasons,
MN-CON
DC-CON
[2]
PS7
M
C
Y
L
Execute toner supply forcibly, and determine the developing bias and the
grid bias in order to obtain optimal density.
[1]
K
F-7-26
0013-4454