Epson Stylus Pro 7400 Service Manual page 158

EPSON Stylus Pro 7400/7800/9400/9800
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
Transition to this sequence is allowed only at inter-page skew
C H E C K
checking (at cut/eject, etc.) At paper initial, the printer moves to left
P O I N T
and right edges detection sequence.
Solid Line:
Broken Line: Printable Area
Right edge
detection position
Previously determined paper width X mm
Operating Principles
Paper
Left edge
detection position
Print Mechanism Components
Left and right edge detection start
Edge sensor LED lights up
Edge sensor sensitivity control
Periodic flushing on the F1_Box
Printing area MIN position
The CR moves to the min. printable
position; + B5 size - 3 mm = 309.31mm
(320CPS)* 1
While monitoring the edge sensor
output, the CR moves toward its home
to go to the target position (320CPS)
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.
Paper right edge
position deflected by 3 mm from previously
determined position?
No
Paper left edge
position deflected by 3 mm from previously
determined position?
No
Edge sensor LED turns OFF.
Return
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 position + 20 mm = 157.31 mm
Figure 2-8. Simplified Detection Sequence for Left and Right Edges (Skew Check)
Revision B
Paper absence detected
Yes
The CR moves toward the opposite direction of
its home by 2 mm (240CPS) from the position
where the sensor output has changed.
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
Left edge position is
smaller than "the min. position -
set margin"?
No
Bigger than the left
edge position detected by paper
presence? * 2
No
No
Skew error detection is
enabled?
Yes
Edge sensor LED turns
OFF.
Error 1
Yes
Yes
Edge sensor LED turns OFF.
Error 2
No
Yes
Yes
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