CHAPTER 4 IMAGE FORMATION SYSTEMCOPYRIGHT © 1999 CANON INC. CANON NP6320 REV.0 DEC. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)4-102. Controlling the DC BiasThe differential amplifier of Figure 4-402 operates when DCBC is 16V or below. (The rangeof DCBC (analog) is 6 to 16V, as set by the copy density cursor or the AE system.)Differential amplifier goes ON.Variable pulse-width oscillator goes ON.DC high-voltage transformer goes ON.The DC bias is applied to the developing cylinder.The copy density knob changes the DC component of the developing bias as shown in Figure4-401.Figure 4-401 Changes in Development Bias(DC component) by Copy Density KnobFigure 4-402DCBCDC component ofdeveloping bias6V to 16V−500V to −0VDC bias(5)-500-400-300-200-100Copy density lever scaleHigh-voltage transformer unit (HVT)PhotosensitivedrumDevelopingcylinderStatic chargeeliminatorRectifier24VT1 drivecircuit AC high-voltagetransformer T124VQ1AC biasswitchingcircuitSquarewaveoscillatorAE sensorCopy densityleverBlackdevelopingassemblyCopy densityknobT2 drivecircuitVariablepulse-widthoscillatorDifferentialamplifierD/Aconverter DC high-voltagetransformer T2ACBONDCBCDC controller PCBMicroprocessor
