224 Troubleshooting Q1860-90918
Image system troubleshooting
Half self-test functional check
The electrophotographic process can be subdivided into the following stages:
Cleaning (removes excess toner from the drum surface)
Conditioning (places a uniform electrical charge on the drum)
Writing (the laser strikes the surface of the drum to create an electrostatic image)
Developing (forms the toner image on the drum)
Transferring (charges transfer the image to the print media)
Fusing (heat and pressure produces a permanent image)
The purpose of the half self-test check is to determine which process is malfunctioning. Perform
the test as follows:
1 Print a configuration page from the control panel
INFORMATION MENU.
2 Open the top cover after the paper advances half-way through the printer (about five
seconds after the main motor begins rotation). The leading edge of the paper should have
advanced past the toner cartridge.
3 Remove the toner cartridge.
4 Open the toner cartridge’s drum shield to view the drum’s surface.
If a dark and distinct toner image is present on the drum’s surface, assume that the first four
functions of the electrophotographic process are functioning (cleaning, conditioning, writing, and
developing), and troubleshoot the failure as a transfer or fusing problem.
If no image is present on the photosensitive drum, perform the following check.
Drum rotation functional check
The photosensitive drum, located in the toner cartridge, must rotate for the print process to work.
The photosensitive drum receives its drive from the main gear assembly. To determine whether
the drum is rotating:
1 Open the top cover.
2 Remove the toner cartridge.
3 Mark the cartridge’s drive gear with a felt-tipped marker. Note the position of the mark.
4 Install the toner cartridge and close the top cover. The start-up sequence should rotate the
drum enough to move the mark.
5 Open the printer and inspect the gear that was marked in step 3. Verify that the mark moved.
If the mark did not move, inspect the main gear assembly to make sure that it meshes with
the toner cartridge gears. If the drive gears function, and the drum does not move, replace
the toner cartridge.
Note This test is especially important if refilled toner cartridges are in use.
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