Canon iR1600 Series, Service Manual

Page: 126 / 738

CHAPTER 3 IMAGE READING/PROCESSING SYSTEM
COPYRIGHT© 2002 CANON INC. 2000 CANON iR1600/iR2000/iR1610/iR2010 SERIES REV.0 MAR. 2002
3-14
4.7 LED Intensity Adjustment
So that the image data read by the CS unit will always be optimum, the length of time
during which the LEDs are ON when reading a single line is controlled.
In LED intensity adjustment, the light of the LEDs is directed to the standard white
plate during pre-scanning, and the image data thus collected is evaluated to see if it is
within a specific range; if, for instance, it is outside the range, the length of time is de-
creased.
4.8 Enlargement/Reduction
The machine allows enlargement/reduction between 50% and 200%, set in increments
of 1%.
4.8.1 Enlargement/Reduction in Main Scanning Direction
The ratio in main scanning direction (drum axial direction) is changed as follows: in
book mode and ADF mode, the original is read at 100%; thereafter, the collected data is
subjected to processing by the image processor PCB to suit the selected reproduction ra-
tio.