Troubleshooting - Canon iR4570 Series Service Manual

Chapter 14

14.2 Troubleshooting

14.2.1 Image Faults
14.2.1.1 Uneven Density
14.2.1.1.1 Uneven Density in Sub Scanning Direction
0007-7464
iR2270 / iR2870 / iR3570 / iR4570 / iR3530
<Description>
This fault can occur when the machine is left alone for about 10 min to 5 hr without removing a paper jam.
<Cause>
When a paper jam occurs, the machine forces the main motor to stop, thus stopping the operation without removing
charges from the surface of the photosensitive drum. If the machine is left alone for a long time with the surface
potential of its photosensitive drum uneven, potential memory tends to occur within a layer of the photosensitive
drum, ultimately resulting in uneven density in sub scanning direction.
<Field Remedy>
To rid the surface of the photosensitive drum of potential memory, leave the machine alone for 30 min after removing
the jam. There is no specific instructions as to how it may be left alone.
<Image Sample>
14-4