Epson Stylus PRO 7000 Service Manual page 73

EPSON Stylus Pro 7000
Paper size detection - right and left edges
Before printing the printer needs to determine the distance from the right
and left paper edges to the right frame and left frame (home position).
As shown in the following flowchart, the printer flushes the heads to
make sure no ink smears the paper as the printheads move across the
paper. Then the carriage moves to where paper should definitely be (if
loaded properly), near the vertical guide line. There the Paper Width
sensor determines the brightness level (high) of the light reflected off the
paper. (If no light is reflected, paper is not loaded or is not loaded
properly and a "Reload Paper" error occurs.) The carriage moves back
toward the home position, where paper definitely should not be if loaded
properly, and determines the brightness level (low) when light is not
Operating Principles
Figure 2-19. Paper Size Detection - R/L edges
Printer Mechanism Operation Outline
reflected off the paper. This procedure is necessary to set the high/low
levels when adjusting for different media types, such as glossy or plain
paper.
Next the carriage moves from the home position toward the opposite
frame and measures the distance from the home position to the opposite
(right) edge of the paper according to the brightness high and low levels.
If the paper edge has not been determined by a certain point (outside of
the printheads' print range), the paper is loaded too far to the right and a
"Reload Paper" error occurs
Once the opposite-side paper edge has been found, the carriage moves
from the opposite frame to the home position and measures the distance
from the opposite frame to the HP-side (left) edge of the paper.
Revision B
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