CHAPTER 4 IMAGE FORMATION SYSTEMCOPYRIGHT © 1999 CANON INC. CANON NP6317 REV.0 APR. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON) 4-1I. PROCESSESA. OutlineThe basic structure of the image formation system is as shown below.• Scanning lamp control system• Primary/transfer corona current and grid bias voltage control system• Developing bias control system• Document density measurement system• Developing assembly/drum cleaning system• Blanking systemFigure 4-101Scanning lampAE sensorLampdriver unitLensHigh-voltagetransformer(HVT)DC controllerPCBGRID ON signal (GRDON)Blank exposure shutterPre-exposure lampPhotosensitivedrumHVTON command (HVTON)(ACBON)(DCBC)DC BIAS control commandGRID BIAS control signal (GRBC)AC BIAS ON command(PEXP)PRE-EXPOSURE LAMP DRIVE command(LAON)LAMP ON commandStatic charge eliminator bias(LIC)AELIGHT INTENSITYCONTROL commandTransfer corona assemblyhigh voltageDeveloping bias