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24 February, 1999
Step 4: Sensor Pattern Density Detection
Process
The development rollers of the respective colors develop the sensor pattern latent
images for K, Y, C, and M generated in Step (2). In Step (4), the ID sensor detects
the densities of the 16 patch patterns for each color. This data goes to memory.
Diffused Reflection ID Sensor
Drum
LED
A259A006.WMF
This copier uses a diffused reflection ID sensor. In addition to the ray directly
reflected from the drum, there are diffuse beams reflected at all angles from the
toner on the drum. This sensor detects image density by receiving some of these
diffuse beams, not by receiving the beam directly reflected from the toner.
Using this type of sensor improves the measurement accuracy of the sensor
pattern densities particularly for Y, C, and M toners. The following explains why.
Color (Y, C, M) toners
V
SP
V
min
(1): Component of light reflected from the drum
(2): Component of light reflected from C, M, or Y toner
Figure A Relationship between the output of the normal reflection type ID sensor
and the amount of toner on the drum for C, M, and Y toners
Diffuse
Beam
Toner
Detector (Diffused
Reflection Type ID
Sensor)
Detector
(Direct Reflection
Type ID Sensor)
2-7
PROCESS CONTROL
Drum
LED
Other Diffuse
A259A007.WMF
Beams
V
SP = (1) + (2)
(2)
(1)
M/A
A259A008.WMF
Toner
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