CHAPTER 3 IMAGE READING/PROCESSING SYSTEMCOPYRIGHT © 2002 CANON INC. 2000 CANON iR1600/iR2000 REV.1 JAN. 20023-144.7 LED Intensity AdjustmentSo that the image data read by the CS unit will always be optimum, the length of timeduring 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 whiteplate during pre-scanning, and the image data thus collected is evaluated to see if it iswithin a specific range; if, for instance, it is outside the range, the length of time is de-creased.4.8 Enlargement/ReductionThe machine allows enlargement/reduction between 50% and 200%, set in increments of1%.4.8.1 Enlargement/Reduction in Main Scanning DirectionThe ratio in main scanning direction (drum axial direction) is changed as follows: in bookmode and ADF mode, the original is read at 100%; thereafter, the collected data is subjectedto processing by the image processor PCB to suit the selected reproduction ratio.The machine varies the ratio based on a linear correction method.
