Canon 1130 Service Manual page 173

CHAPTER 6 IMAGE FORMATION SYSTEM
7. Auto Gradation Correction in User Mode
a. Outline
The copier's auto gradation correction is designed to produce ideal gradation in images.
A 64-gradation halftone image (for each color) is printed in user mode, and the density of the
output is read by the CCD of the reader unit for the following control:
• Correcting the laser output.
• Correcting gradation
b. Operations
For instructions on how to operate user mode, see Chapter 1.
1) Generate auto gradation correction test prints 1 and 2 (64 gradations for each color) in user
mode. Make sure that test prints 1 and 2 differ in resolution.
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Test print 1
2) Place the generated test print on the copyboard glass, and have the copier read it. The copier
will determine the laser control value and the gradation control value from the image data it
collected from the test print.
Thereafter, in the case of the CLC1140/1160/1180, a sample color toner image (patch
image) is deposited on the photosensitive drum using the value thus determined. The
patch image is then read by the gradation sensor to determine the target value for the new
gradation correction control mechanism. (See IV.E. of Chapter 6.)
8. Checking the LED Activation for the Potential Measurement Circuit
LED1 remains on at all times as long as the copier is supplied with power, indicating that the
potential sensor is operating normally. If it is not in a normal way, suspect that the 24 V-F power is
not supplied or the potential measurement unit is faulty.
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COPYRIGHT © 2002 CANON INC.
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Figure 6-207
CANON CLC1100/1130/1150/1160/1180 REV.2 FEB. 2002 PRINTED IN JAPAN (IMPRIME AU JAPON)
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Test print 2