Canon LBP-CX Series Service Manual page 83

Pressing a control panel circuit switch generates
a signal (PSWO - PSWS) sent to microcomputer IC3
(video controller) via input port IC40. Upon receiving
this signal, the microcomputer IC3 directs the per-
formance of the task assigned to that switch. For
example, if the SHIFT and FORM FEED switches are
pressed simultaneously while the printer is off-line,
the self-test function produces a print-out. For this,
microcomputer IC3 directs the video signal generator
(within the video controller) to form the video signal
(VDO, VDO: differential signals) for a repeated pat-
tern of alphanumerics to be printed out.
1. Test switch
Figure 3-65
The test switch is located on the left side of the
left panel. (See Fig. 1-4 in Chapter
l.)
After the
photosensitive drum has stopped (and the READY/
WAIT indicator is lit), pressing this switch once re-
sults in a one page print-out of the vertical line test
print.
Pressing the test switch sends a TEST PRINT
command (TSTPT) to multiplexer IC2 l 9. This
command is further passed to microcomputer IC208
on the DC controller, which directs printing a test
print.
The printing areas for test prints using A4, BS,
legal, and letter size paper are shown in the diagram
below.
Finished paper
3 / 7
2
=t-++
~~&%! P ~ p e r . f e e d
~:
d1rect1on
'~I
Pdo,.bl• •re•
1~1
2-"}
-+- - -
- I -
(Unit: mm)
A4 size machine print area
Figure 3-66
COPYRIGHT
©
BY CANON INC. CAllON LBP-CX SERIES RE.V.2 JULY 1985 PRINTED IN JAPAN (IMPRIME AU JAPON)
3-49