2. Control MethodThe potential sensor inside the machine measures the dark area potential (VD) andthe light area potential (VL1 ), and the machine makes corrections based on the mea-surements to enable a target value.The light area potential (VL2) for developing bias is measured based on the correc-tion conditions, and the machine uses the measurement to determine the DC componentof the developing bias.Tables 4-101 and -102 show how many times the machine measures and correctspotential and when it initiates control.Table 4-101 Measurement/Correction for Potential ControlTable 4-102 Timing of Potential ControlCHAPTER 4 IMAGE FORMATION SYSTEM4-2 COPYRIGHT © 1997 CANON INC. CANON NP6560/NP6360/NP6260 REV. 0 NOV. 1997 PRINTED IN JAPAN (IMPRIME AU JAPON)Correction MeasurementV D 8 (max.) 8 (max.)VL1 8 (max.) 8 (max.)VL2 0 1ModeText modePhoto modeTiming• Once every power-on.• Once while making thefirst copy between 10and 60 min of power-on.• Once while making thefirst copy after 60 min ofpower-on.• Once while making thefirst copy in photo modeafter power-on.
