COPYRIGHT © 1999 CANON INC. CANON 660/2100 REV.0 FEB. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)3. ITD Cleaning Bias Generation CircuitThis circuit is controlled by four signals (Figure 4-610) from the DC controller PCB,and generates the ITD cleaning DC (positive) bias, ITD cleaning DC (negative) bias, andITD cleaning AC bias for application to the ITD cleaning roller.The ITD cleaning DC (positive) bias drive signal is used to turn on and off the DC(positive) bias applied to the ITD cleaning roller, while the ITD cleaning DC (negative)bias drive signal is used to turn on and off the DC (negative) bias applied to the ITDcleaning roller.The ITD cleaning AC bias drive signal, on the other hand, is used to switch the ITDcleaning AC bias level to suit the conditions of the environment.Figure 4-6104. Fixing Separation Bias Generation CircuitThis circuit is controlled by the fixing separation DC bias drive signal from the DC con-troller PCB, and generates the fixing separation DC bias for application to the upper fix-ing roller.The voltage applied to the upper fixing roller is controlled by the fixing separation DCbias drive signal. The level of the fixing separation DC bias, further, is kept to a specificlevel.CHAPTER 4 IMAGE FORMATION SYSTEM4-32DC controllerPCBITD cleaning biasgeneration circuitITD cleaning DC (positive)bias drive signalITD cleaning DC (negative)bias signalITD cleaning bias levelswitch signalAC+DC (positive) or DC (negative)ITD cleaning AC biasdrive signalITD cleaning rollerDownload free service manual at http://printer1.blogspot.com
