Chapter 77-8F-7-97.4.4 Determining the Laser Output0009-3543To measure the light area potential (VL1) for the first time after the power switch is turned on, the machine uses the most recent laser output level (LP0),and measures the drum surface potential using the potential sensor. The DC controller PCB compares the drum source potential and the target potential;if the measured potential is +/-10V of the target value, the machine corrects the potential of the laser output, and measures the potential once again. Themachine executes potential measurement a maximum of 8 times, and also corrects the lower output level as many times. In addition, the machine measuresthe light area (VL2) for the developing bias for use in determining the laser output (LP) needed to attain the target potential.F-7-107.4.5 Determining the Developing Bias0009-3544The machine determines the developing bias (VDC) as follows with reference to the drum surface potential (VL2):VDC = VL2 + delta VDCFor copier potential, delta VDC=110 VFor printer potential, delta VDC=85 to 110 V (i.e., the printer potential varies to suit the reading of the environment sensor, thus ensuring the reproductionof correct line width)WMUPRWMUP STBY200 CPotential sensorPrimary chargingGrid biasVpc Vpc Vpc VpcVD+6V-6VVDVDCorrection controlsequence startPotential controlsequence startPrevious potentialVDVD VD VD VD VDTarget VDFixing assembly temperature 195 CWMUPRWMUP STBY200˚CPotential sensorDeveloping bias(DC)LaserLP0 LP0 LP0 LP0 LP0 LPVL1 VL1 VL1 Target VL1VL1VL1Correction controlsequence startFixing assemblytemperature 195 Deg CVL1+6V-6VVL1VL1VL1Previous potentialTarget VL1Potential controlsequence startVL2
