CHAPTER 11 TROUBLESHOOTINGCOPYRIGHT © 1999 CANON INC. CANON NP6512/6612/7120/7130/7130F REV.0 AUG. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON) 11-57C. Troubleshooting Image Faults1 The copy is too light. (halftone area only)2 The copy is too light. (including solid area)3 The copy is too light. (enter image, appreciably)YES/NOYESNONOYESYESNOYESNOCauseLens, Reflect-ing plate, AEsensor, Staticeliminator------------Transfercharging rollerCopy paperTransfer lowerguide, Varis-torCompositepower supplyPCB, DCcontrollerPCBDrum unitDevelopingbias, Develop-ing biasterminalStep123456ChecksClean the lens, reflecting plate, AE sensor,and static eliminator. Is the problemcorrected?Turn off the power in the middle of acopying run, and open the machine's topunit. Is the toner image before transfermore or less normal? (Be sure to make acheck in a short time to protect the drumfrom light.)Is the transfer charging roller normal?Try fresh copy paper. Is the problemcorrected?Measure the electrical resistance on thetransfer lower guide plate and the sideplate (metal) of the fixing assembly. Is it0Ω?Replace the drum unit. Is the problemcorrected?ActionEnd.Go to step 6.1. Mount the transfercharging rollercorrectly.2. Replace the transfercharging roller.1. The copy paper maybe moist. Instruct theuser on the correctmethod of storage.2. Inform the user thatusing non-recom-mended paper maynot bring the bestresults.1. Check to find out ifthe transfer lowerguide happens to be incontact with a metalpart (side plate).2. Replace the varistor.1. Check the transferhigh-voltage terminalcontacts for electricalcontinuity.2. Check the compositepower supply and theDC controller PCB.End.Replace the electric unit(composite power supplyPCB, DC controllerPCB).
