Atvc Control (Transfer Bias Level Correction); Pascal Control (Image Gradation) - Canon iR C3200 Series Service Manual

9.4.5 ATVC Control (transfer bias level correction)

The ATVC control mechanism is used to determine the optimum level of transfer voltage for transfer of images from
the photosensitive drum to the ITB, and from the ITB to paper.
The level of transfer voltage is corrected in relation to changes in temperature/humidity, deterioration of rollers, and
types of paper.
Description of Control
1. A reference voltage is applied to the transfer roller, and the level of current that occurs in response is checked by
the high-voltage PCB and communicated to the CPU on the DC controller PCB as feedback.
2. The machine executes transfer using a transfer voltage which is the result of correction by the CPU.
Item
Primary
transfer
Secondary
transfer

9.4.6 PASCAL Control (image gradation)

The PASCAL control mechanism is used to stabilize gradation characteristics of images on paper.
It makes up for the changes in gradation occurring in response to changes in temperature/humidity or as the machine
is used over time.
- PASCAL Control for Half-Speed
The mechanism is used to correct the changes in the gradation characteristics that otherwise would occur when thick
paper, special paper, or transparency is used. The test print used for the mechanism is the same as the test print
used for plain paper.
Description of Control
Start-up
V
Prints out the test pattern stored in the main controller (3 types).
V
Uses the scanner to read the test print (previously printed out) set in the reader.
V
Prepares the image correction table A (data processing).
V
End
Timing of Control
T-9-26
Description
Applies a reference voltage to the primary charging roller.
Uses the high-voltage PCB (HV-2) to check the level of current, and the result is
fed back to the CPU for determination of the optimum level.
Applies a reference voltage to the secondary transfer external roller.
Uses the high-voltage PCB (HV-3) to check the level of current, and the result is
fed back to the CPU for determination of the optimum level.
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