Epson Stylus Pro 7400 Service Manual page 157

EPSON Stylus Pro 7400/7800/9400/9800
Paper size detection sequence (front edge)
Conditions:
For execution of this processing, the paper level threshold value must be
known. (Execute this processing after detection of the right and left edges.)
Error display:
Set the paper correctly
When the paper width detection function is turned off, use the paper size front
position as the user paper setting position. (On the assumption that detection
is not made by the edge sensors)
Operating Principles
Front edge detection start
The CR moves onto Fl_Box. (320CPS)
The CR moves to the paper left upper detection
While monitoring the edge sensor output, the PF moves in
the negative direction (picks up paper) (40CPS)
The PF stops if paper absence is
Paper absence detected
While monitoring the edge sensor output, the PF moves in the
positive direction (feeds the paper forward) (5CPS)
The position where paper presence is detected is judged to be
the left front edge position of the
The CR moves to the paper right upper detection position
No
Paper absence is detected by edge sensor?
While monitoring the edge sensor output, the PF moves in
the positive direction (feeds the paper forward) (5CPS).
PF stops if paper presence is detected.
(Prevention of skew at leading
Paper absence detected
While monitoring the edge sensor output, the PF moves
in the negative direction (picks up paper) (40CPS)
The PF stops if paper absence is
Paper absence detected
While monitoring the edge sensor output, the PF moves in the
positive direction (feeds the paper forward) (5CPS).
The position where paper absence is detected is
judged to be the right front edge position of the
The upper right leading edge of paper is determined as the
front position of the paper
Edge sensor LED turns OFF.
Figure 2-7. Paper Size Detection Sequence (Front Edge)
Print Mechanism Components
Note "*1":Paper left upper detection
1
position*
2
detected*
No
Yes
paper* 2
(320CPS)* 4
Yes
4
edge)*
No
Yes
detected* 2
No
Yes
3
paper*
size* 5
Edge sensor LED turns OFF.
Return
Revision B
position = Paper left edge
position + 27.5 mm
"*2":PF maximum travel =
- 260mm (Self-diagnostics
mode: - 340mm)
No change in sensor output
even when this travel has
been exceeded is handled as
an error.
"*3":PF moving target position =
The 1st nozzle position
(0.00 mm)
No change in sensor output
even when this position has
been passed is handled as
an error.
"*4":Paper right upper detection
position = Paper right edge
position - 27.5mm
"*5":In the figure below, the left
upper leading edge is
handled as the paper size
front position. (On the
assumption that the paper
front edge is not correctly
perpendicular to the paper
feed direction)
Solid Line: Paper
Broken Line: Printable Area
Left Upper
Leading Edge
Right Upper
detection
Leading Edge
position
detection
position
Error
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