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Pre-Scanning
Roller
Registration Sensor
! CCD scanning: Uses the white plate above the ADF exposure glass
! CIS scanning: Uses the white roller below the CIS.
Slide 273
# Shading correction, which attempts to compensate for slight distortions caused
by the differences in brightness of the light elements due to wear, temperature
variation, or distortion by the lenses, is done for the first sheet:
$ The original is fed for a few clock pulses after the registration sensor
detects the leading edge of the original.
$ The original is then delayed slightly at the ADF exposure glass while the
CPU uses the white plate (above the ADF exposure glass when the ADF is
closed) to determine the white peak level for the job.
$ The pre-scanning roller, ADF transport belt, and transport rollers feed the
original over the ADF exposure glass and under the CIS, until it reaches the
exit roller.
$ If the reverse side of the original is to be scanned, the CPU uses the
surface of the white platen roller to determine the white peak level for the
job.
Shading Correction
ADF Transport
Belt
ADF Exposure
Glass
273
CIS
White Roller
Exit Roller
V-C3 Training
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