Epson Stylus Pro 7400, Service Manual

Page: 158 / 428

EPSON Stylus Pro 7400/7800/9400/9800 Revision B
Operating Principles Print Mechanism Components 158
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Simplified detection sequence for left and right edges (skew check)
When the paper width detection function is turned off, left and right edge
detection (skew check) is not carried out.
Error display:
1: Set the paper correctly
2: PAPER NOT STRAIGHT
Figure 2-8. Simplified Detection Sequence for Left and Right Edges (Skew Check)
C H E C K
P O I N T
Transition to this sequence is allowed only at inter-page skew
checking (at cut/eject, etc.) At paper initial, the printer moves to left
and right edges detection sequence.
Previously determined paper width X mm
Solid Line: Paper
Broken Line: Printable Area
Left edge
detection position
Right edge
detection position
Left and right edge detection start
No
Periodic flushing on the F1_Box
Yes
Printing area MIN position
The CR moves to the min. printable
position; + B5 size - 3 mm = 309.31mm
(320CPS) *
1
No
While monitoring the edge sensor output, the
CR moves to the target position by 5CPS
The position where paper absence is detected is
judged to be the left edge position of the paper
The paper width determined by the previously executed
left and right edge detection (at paper initial or skew
check) is added to the left edge position. The resultant
position is regarded as the paper right edge position.
No
Edge sensor LED turns OFF.
Return
Edge sensor sensitivity control
Edge sensor LED lights up
Left edge position is
smaller than “the min. position -
set margin”?
Yes
No
No
Yes
While monitoring the edge sensor
output, the CR moves toward its home
to go to the target position (320CPS)
The CR moves toward the opposite direction of
its home by 2 mm (240CPS) from the position
where the sensor output has changed.
Bigger than the left
edge position detected by paper
presence? * 2
Yes
Error 2
Edge sensor LED turns
OFF.
Error 1 Yes
Yes
Edge sensor LED turns OFF.
No
Note "*1":Min. printable position = 137.31mm - 7.0mm (Reserved width)
B5 size (182.0mm) - 3.0mm = 179.0mm
"*2":Paper presence position
Paper right edge po 20 mm = 157.31 mm
Paper absence detected
Paper left edge
position deflected by 3 mm from previously
determined position?
Paper right edge
position deflected by 3 mm from previously
determined position?
Skew error detection is
enabled?