134 Troubleshooting EN
Half self-test functional check
The electrophotographic process can be subdivided into the following stages:
l Cleaning (removing excess toner from drum surface)
l Conditioning (placing a uniform electrical charge on drum)
l Writing (laser strikes surface of drum to create latent image)
l Development (formation of the toner image on drum)
l Transfer (charge to transfer the image to paper)
l Fusing (heat and pressure to produce a permanent image)
The purpose of the Half Self-Test Check is to determine which process is malfunctioning. Perform the
test as follows:
1 Initiate a self-test.
2 Open the Printer Door after the paper advances half-way through the printer (about eight
seconds after the 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 - see Chapter 5.) Troubleshoot the failure as a transfer or fusing problem.
If NO image is present on the photosensitive drum, perform the following functional checks:
1 Make sure you have removed the entire length of the sealing tape from the toner cartridge before
you installed the cartridge.
2 Drum Rotation Functional Check.
3 High Voltage Power Supply 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 Drive assembly. To verify whether the drum is
rotating:
1 Open the Printer Door.
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 Printer Door. 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 Drive assembly to ensure that it is meshing with the toner
cartridge gears. If the drive gears appear functional, and the drum does not move, replace the toner
cartridge.
Note This test is especially important if refilled toner cartridges have been used.
Service.book Page 134 Thursday, September 14, 2000 11:15 AM
