Canon iR8500 Service Manual

Also see for ImageRunner iR8500 Series: Function guide Servise manual Service manual Service manual

Contents

COPYRIGHT © 2001 CANON INC. 2000 2000 2000 2000 CANON iR8500/7200 REV.1 AUG. 2001CHAPTER 6 TROUBLESHOOTING6-41.1.2 Making Checks on the Printer Side (1/2)F06-101-02Is there adifference in densitybetween frontand rear?Is the rearlighter?Turn the adjustingscrew at the front ofthe primary chargingassembly counter-clockwise (2 turnsmax.).Turn the adjustingscrew at the rear ofthe primary chargingassembly counter-clockwise (2 max.).Turn off and then on the powerswitch, and generate a single testprint using PG7 or PG4.1. If there still is a difference in density after giving the adjustingscrew 2 turns on one side (each turn causing a change ofabout 0.7 mm), check the charging assembly, scanning lamp,and scanner for dirt.2. When turning the adjusting screw counterclockwise, take careso that the distance between the wire and the grid is not lessthan 7.5 mm.Is the outputfree of a fuzzy imageand the densityappropriate?Is the test print PG6(solid white) foggy?Is the reading of‘VDM’ between 360and 420?Is the readingof ‘VL1M’ between50 and 90?Check the following of thedeveloping assembly system:1. Developing bias2. Sleeve for toner coating YESNOYESNO YESNONOYESNOYESYESNOIs there ahorizontal line inthe image?Is there ahorizontal line inthe image?Using PG4, PG7, and PG8YESYESNONOExecute potentialcontrol.Check the image using PG4. Check PG8 (solid black).Caution:Moving the wire away from the wire makes the image darker,while bringing it closer makes the image lighter.Reference:Make the following selections inservice mode:COPIER>DISPLAY>DPOT>VDM.Make the following selections inservice mode:COPIER>DISPLAY>DPOT>VL1M.AClean the following, and checkthem for adhesion of foreignmatter:[1] Dust-proofing glass[2] Charging assemblies[3] Developing cylinderCheck the following; if faulty,replace it:1. Laser output2. Potential control systemCheck the primary chargingsystem and the potential controlsystem; if normal, replace thephotosensitive drum.Perform the following:1. Vary the settings of the following with reference tothe following table: ADJUST>V-CONT>VD-OFST andADJUST>V-CONT>VL-OFST:VD-OFST -4 -3 -2 0 +2 +3 +4VL-OFST +4 +3 +2 0 -2 -3 -4DefaultLighter images Darker images