New Gradation Correction Control (Patch Detection; Clc1140/ 1160/1180); Outline; New Gradation Correction Control (Patch Detection) - Canon 1130 Service Manual

E. New Gradation Correction Control (patch detection; CLC1140/
1160/1180)
The CLC 1140/1160/1180 makes use of the following control mechanism to ensure highly
stabilized hues:

1. Outline

To enhance the hues of images, the machine forms a color toner image (patch image) on the
photosensitive drum, and measures the light reflected by the image to compute the changes that
may have occurred in toner concentration in reference to the intensify of light.
Using the computed changes, the machine operates the new gradation correction control
mechanism.

2. New Gradation Correction Control (patch detection)

The machine uses the sample color toner image (patch image) it has created on the
photosensitive image and the LED sensor (PS) to take readings in the form of the intensity signal of
the reflected light and the reference signal. It then compares these signals against the target value
stored in the RAM to compute any changes in toner concentration for use in gradation correction
control.
The following is the flow of gradation correction control:
COPYRIGHT © 2002 CANON INC.
Sets the initial reference signal (P-SENS-Y/M/C/K).
(at time of shipment, sensor replacement)
Sets the target signal (P-TRGT-Y/M/C/K; after auto gradation
correction).
In response to a press on the Start key, rotates
the photosensitive drum.
Checks the light reflected by the drum surface
(absence of toner).
Creates a sample image (patch image) on the
photosensitive drum.
Turns on the LED (to shine the photosensitive drum).
Measures the intensity of the light reflected by the sample
image (patch image) during copying operation.
Compares the data against the target data to compute changes
that may have occurred in the concentration of toner
(intensity of light).
Table6-412a
CANON CLC1100/1130/1150/1160/1180 REV.0 FEB. 2002 PRINTED IN JAPAN (IMPRIME AU JAPON)
CHAPTER 6 IMAGE FORMATION SYSTEM
6-46a