Image Position Adjustment In The Main Scan Direction; Paste Shadow Erase Mode - Ricoh C231 Service Manual

2.2.5 IMAGE POSITION ADJUSTMENT IN THE MAIN SCAN
DIRECTION
To adjust the image position of the original across the printout, the image can be
shifted 1.9 mm in the main scan direction using SP mode No. 31 (platen mode)
or No. 37 (ADF mode).
The image shift in the main scan direction is done by changing the relationship
between the position of the image data on the CIS and on the thermal head. Data
for one main scan line is stored in a line memory. When the data is output from
memory, the output timing is changed to shift the image.
Data from CIS
After A/D Conversion
Data from
Thermal Head Driver,
No Image Shift
Data from
Thermal Head Driver,
Image Shift x mm
(SP 31 or 37)

2.2.6 PASTE SHADOW ERASE MODE

Due to the characteristics of the contact image sensor, shadows of a paste-up
original tend to appear on copies. To counter this, the paste shadow erase mode
can be used by pressing the paste shadow erase key on the operation panel.
When this mode is selected, the black or white threshold level is slightly lowered.
At the same time, the emphasis in the sub-scan direction in the MTF correction
process is weakened to make the shadows inconspicuous.
The strength of the paste shadow erase level can be changed with SP No. 28.
SM
CIS Center
0
Thermal Head
Center
0
x mm
Thermal Head
Center
0
2-17
IMAGE-PROCESSING
3072
3072
3072
C231D521.WMF
C231/C237/C238