Thermal Head Test; Operation: (To Enter Test Pattern Image Mode) - Ricoh C211 Service Manual

4.4 THERMAL HEAD TEST

The function of this mode is to distinguish if the cause of the image problem
is located before or after image processing.
Output image: The normal output of this test pattern image mode is one
of the dither matrix patterns as illustrated below.
Master processing length:
Main scan (Horizontal) direction:
Sub-scan (Vertical) direction:
Test Pattern Image

F lu o re sce n t L a m p
C C D
O rig in a l F e e d
M o to r
The test pattern is generated by the image processing PCB.
[Example] Problem:
Possible Cause 1
Possible Cause 2

4.4.1 OPERATION: (To Enter Test Pattern Image Mode)

1) Turn the power switch off
2) Remove the front cover.
C224
A /D C o n ve rsio n M a in C o n tro l
P C B
P C B
Vertical white lines appear on the print.
If the same problem appears on the output
image from the thermal head in test pattern
image mode, the cause is in area
B, as shown above.
If the output image from the thermal head is
correct in test pattern mode but the output
image in the normal mode is incorrect, the
cause is in area A, as shown
above.
Full width of the thermal head
Same as the vertical size of
the original set on the original
table.
Magnified Test Pattern Image
Test P atte rn in Test P attern in
Lin e M od e
M a ste r F e e d
M o to r
4-12
P ho to M o de

T h e rm a l H e a d
SM