Chapter 77-5F-7-6SERVICE MODE:- COPIER> OPTION> BODY> PO-CNT (enabling/disabling potential control)0: potential control OFF1: potential control ON (default)- COPIER> ADJUST> V-CONT> EPOTOFST (potential sensor offset value input)If the DC controller PCB has been replaced or the RAM on the DC controller PCB has been initialized, enter the value indicated on the service label.- COPIER> ADJUST> V-CONT> VL-OFST (VL target potential offset value input)If the DC controller PCB has been replaced or the RAM on the DC controller PCB has been initialized, enter the value indicated on the service label.- COPIER> ADJUST> V-CONT> VD-OFST (VD target potential offset value input)If the DC controller PCB has been replaced or the RAM on the DC controller has been initialized, enter the value indicated on the service label.- COPIER> FUNCTION> DPC> OFST (potential sensor offset adjustment)This mode item is part of the series of procedures that must be performed when the potential sensor unit is replaced. It is not performed on its own.7.4.3 Determining the Optimum Grid Bias 0010-8041iR7105 / iR7095 / iR7086The grid bias is determined so that the drum surface potential will be identical to the target potential. (The primary charging bias is set to a fixed value.)F-7-760 min laterPotentialcontrolPotentialcontrol PotentialcontrolPotential controlfor transparencyMain powerswitch ONFixing assembly temperature(end of fixing assembly warm-up)[1] The control panel power switch is turned on.[2] The front door is opened/closed.Start key ONStart key ON10 min later1 hr laterStarting when the fixing assembly temperature reaches 193 deg C,executes potential control every 10 min and 60 min.After previous potential control,executes potential control every hour.PotentialcontrolWMUPRWMUP STBY193 198Potential sensorPrimary charging biasGrid bias650 V 550 V or 750 VMeasurement(VD2) Measurement(VD1orVD3) Measurement (target VD)Vg550V 650V 750VVD1VD2VD3Grid biasMeasurements are taken multiple times todetermine the relationship between the drumsurface potential (VD) and the grid bias.A grid bias (Vg) needed to attainthe target VD is determined.Potential control sequence startedCharging characteristicscurveIf the target VD is attained using thismeasurement, the control is ended;otherwise, compensatory control isAfter measuring VD2, VD1 will be measuredif VD2 is greater than the target VD; if smaller,VD3 will be measured.
