Canon iR C2880 series, Руководство по обслуживанию

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Chapter 5
5-15
Service Mode:
COPIER>OPTION>BODY>DST-POS (level 1)
- use it to set an original reading position when the ADF is in use.
COPIER>OPTION>BODY>DFDST-L1 (level 1)
- use it to adjust the dust reading detection level for between sheets.
COPIER>OPTION>BODY>DFDST-L2 (level 1)
- use it to adjust the dust reading detection level for the end of a job.
5.3.7 Image Processing
5.3.7.1 Overview
0013-8593
/ / / / iR C3380i / iR C3380 / iR C2880i / iR C2880
The image processing system has the following major specifications and functions:
F-5-29
The PCB used by the image processing system has the following functions:
The machine processes images using its reader controller PCB line by line, and the processing consists in the following;
(1) Analog Image Processing
(a) drives the CCD
(b) performs gain correction and offset correction for the CCD output
(c) performs A/D conversion for the CCD output
(2) Digital image Processing
(a) performs shading correction
F-5-30
5.3.7.2 Driving the CCD
0013-8594
/ / / / iR C3380i / iR C3380 / iR C2880i / iR C2880
The machine's CCD sensor is a linear image sensor that consists of 3 lines (RGB, 1 line each), and it is composed of 7488-pixel photocells. The signals generated
through photo conversion at the light-receiving segment are sent as analog signals according to pixels in the order of G, B, and R.
- CCD Number of lines: 3 (RGB, 1 line each)
Number of pixels: 7488
Size of pixel: 42.3 um
- Shading Correction Shading correction; executed for each job
Shading adjustment: executed in service mode
- Reader Controller PCB drives the CCD, performs analog image processing, performs A/D conversion, performs shading
correction
Reader controller PCB
CCD
Analog image processing block Digital image processing block
Shading processing Analog image
processing
A/D
conversion
Contact image
sensor (CIS)
Controller block
CCD (RGB, 1 line each)
Analog
image signal
Analog
image processing
- gain correction
- offset correction
A/D
conversion
CCD drive control
SCD control
signal
Line correction
data
Digital
image signal
Even-numbered
pixel
Odd-numbered
pixel
Odd-
numbered
pixel
Even-
numbered
pixel
CCD/AP circuit
10
Digital
image signal
8
Reader controller PCB
Contact image sensor (CIS)
Target
value
J203
EEP-ROM
SRAM
CPU
Shading
correction