Canon NP6012 Service Manual

Also see for NP6012: Service manual

BREOPERATIONSAND1)(NG3. Controlling the Power Supply to theFixing HeaterThe temperature of the fixing heater iscontrolled by controlling the power suppliedto the fixing heater.The power to the fixing heater is con-trolled by controlling its phase.The microprocessor on the DC controllerPCB controls the output timing of the fixingheater driver signal (HTRD) so that powersuited to the target temperature of the fixingheater may be supplied; this is to control thephase of the power supplied to the fixingheater.HTRD | S|)' H '\ ‘ Ht \ H{ t }' t }Supply power|__ | i” ¢ _ |\to the heater rsVfFigure 3-4103-54 COPYRIGHT © 1995 CANON INC.4. Correcting the Variation in theResistance of the Fixing HeaterThe plane-shaped heater used as thefixing heater has production variations in itsresistance that would hinder proper execu-tion of thermal control of the fixing heater.To correct possible problems, the copiercompensates for the variations in terms ofseven settings of the resistance, whose values are read by a microprocessor.The resistance of the fixing heater isdecided based on the combination ofthe jumper wires connectedto the con-nector of the thermistor (TH1); seeFigure 3-411. :The resistance ischecked and appro-priate settings are made at the factorywhen the fixing assembly is assem-bled; do not rearrange the jumperwires, : ;Figure 3-411CANON NP6012/NPGOT2F /NPG2I2 REV.1 SEPT.1905PRINTEDINJAPAN (IMPRIMEAUJAPON)