Epson Stylus Pro 9000 Service Manual page 48

EPSON Stylus Pro 9000
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 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.
Operating Principles
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 measure the distance
from the opposite frame to the HP-side (left) edge of the paper.
Printer Mechanism Operation Outline
Revision B
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