Panasonic UF 885 - Panafax B/W Laser, Service Manual

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Panasonic UF-885 / 895
207
Shading Correction Circuit
The Shading Correction Circuit, included in IC160, is provided to correct for reduction in LED lamp intensity around the optical
lens and LED lamp intensity distortion due to shading of each bit. This circuit scans the reference white on the transmitting
document plate immediately before the document reaches the scanning position and writes a compensation value according to
the distortion of the waveform, at the time, into the S-RAM (IC170, IC171, IC172).When the actual picture signal is input, the
circuit corrects the picture signal shading, according to this compensation value. This shading is carried out for each page
during transmission or copy.
Offset Control Circuit
The Offset Control Circuit consists of IC161, IC160 and IC118, and controls the black level of the CCD output to be at 0V by
using the IC118.
Picture Signal Binary Coding Correction Circuit
The Picture Signal Binary Coding Correction Circuit is included in IC160. It is used to obtain a binary coding signal which is a
corrected picture and error diffused signal of a false halftone signal, which is detected from a shaded picture signal.
CCD Output
ABC Circuit Output
+5V
R673
C650
R674
IC180
IC180
32
36
19
IC112
IC160
M86075
Control
Circuit
41
39
40
AGN
VOUT1
0V
3.0V
0V