Arcdat Control - Canon iR C3380 series Service Manual

7.3.8 ARCDAT Control

/ / / / iR C3380i / iR C3380 / iR C2880i / iR C2880
The machine performs abridged D-half control to attain ideal gradation characteristics and to reduce downtime (by the main controller).
1. Start-Up Timing
- when the power is turned on
- during post-rotation executed every 25 prints (*1)
- during return from sleep
*1: When printing an original with an image ratio of 25% or less.
2. Particulars of Control
In the presence of a specific condition, the DC controller forms a patch pattern of each color (Y, M, C, Bk) on the ITB (a single pattern for each color, a total of 4
patterns). Thereafter, the DC controller measures the patch pattern using the patch image sensor (UN14), and sends the result back to the main controller, which in
turn compares it against the abridged D-half reference data backed up in memory and uses the difference as the offset value for D-half.
[1] Patch image data
[2] Density data
[3] Abridged D-half control
[4] Video data
UN16: patch image sensor
3. Flow of Operation
ITB
UN16
Laser Scanner
unit
[1]
[4]
D-CON
[2]
[3]
M-CON
F-7-28
Chapter 7
0013-8492
7-21