Banding appears as light and dark horizontal lines on a page that is supposed to be uniformly gray. It is due to variation in the speed of the paper as it moves from roll to roll during development or transfer. It is undetectable when printing text and is mostly noticeable on fine dot or horizontal line patterns. Inspect the gear train and the paper feed rollers for wear, damage, dirt or binds.
Areas that are supposed to stay blank are getting small amounts of toner deposited on them. Clean the erase lamps and the printhead window. Rough paper can cause background on some papers. Change paper and run the print test again. Printing on coated paper can also cause background.
Users who run large jobs with very dense graphics in high humidity environments may get some print quality improvement from increasing the Transfer setting; users with more normal jobs will see no difference. Make sure the HVPS contacts to the transfer roll housing are in good condition.
Black output is usually caused by an incorrect high voltage in the printing process, resulting in toner development on the entire photo-conductor drum. Check the condition of each HVPS contact and make sure they spring back when pressed. Check the continuity of the HVPS cable. Make sure the voltages are correct; if they are not, replace the engine board.
If no other trouble is found replace the HVPS.
Inspect the printhead shutter for proper operation and make sure the actuator on the cartridge is present and extends into the printhead shroud when the printer top cover is closed. A failed printhead/laser will cause a Service error rather than blank output.
Check the continuity of the HPVS cable. The HPVS and transfer roll contacts should be clean and spring back when pressed. Make sure the transfer roll contact under the left bearing is making contact with the HVPS.
Blurred or Fuzzy Print
This can be caused by a damaged gear train or by paper slippage in the feed roll or transfer roll. Also see Banding.
Inspect the HVPS contacts; make sure each spring loaded contact returns when pressed and released. Inspect the transfer roll housing contacts for damage or contamination. Check the gear train for damage, binds, or wear.
Possible causes: no voltage reaching the printer, LVPS failure, blown LVPS fuse, failure of the On/Off switch linkage, or a shorted electrical component.
Check for the indicated voltages at the LVPS connection to the engine board. If no voltages are present, check fuse and the poser switch before replacing the LVPS.
If some voltages are present but all are not correct, disconnect all cables except the LVPS from the engine board.
(Areas of the page are covered by faint 6 mm circles).
This print defect is usually caused by the print cartridge. If it is not the problem, verify that the tab on the transfer roll housing is touching the contact on the HVPS; the transfer roll housing should have continuity to ground. Make sure the HVPS ground lead to the side frame is in place and making good contact.
Horizontal Void or Streak
This is usually due to the cartridge not being installed correctly. Check the printhead/laser area for obstructions, and check the mechanical workings of the print cartridge and printhead shutter. If nothing is found, see “Blank Page” and follow those instructions.
Light print is frequently caused by a worn out print cartridge. Clean the transfer roll by powering on and off two or three times, leaving the printer on for about two minutes each time. Other causes are the same as for “Blank Page”.
Make sure Print Darkness on the customer/operator menu is set to Normal or Dark. Increasing the diagnostics mode Print Contrast setting will darken print further. On some HP printers lowering the number increases the density.
PostScript emulation output may appear lighter than PCL emulation output or a test print; this is not a defect. Verify on the Print Test that the print is too light before performing service.
Regularly Spaced Marks
This is caused by a defect on one of the rolls or gears in the print process. The damaged part can be determined by the spacing of the marks. Find and replace the damaged part.
Residual Image – the “walking” of a leftover image down the page – is probably the result of failed erase lamps not discharging the photoconductor, or of a failed cleaner inside the print cartridge. It can also be caused by a failed fuser hot roll retaining toner and redepositing on the page. Check that the erase lamp voltage at engine board is +24 VDC and that the cable has continuity.
To test the erase lamps, jumper engine board to ground.
Random marks are nearly always due to a mechanical problem or due to foreign matter loose in the printer or in the print cartridge.
Vertical Void or Streak
Do a developed image test to determine if the defect is occurring before or after the transfer process.
If you see the defect on the photoconductor beam path, check the operation of the printhead shutter/laser beam path and clean the window with a lint-free cloth folded over a cotton swab; do not use a bare swab and do not use any cleaning fluids or water on the printhead/laser window. Inspect the HVPS. Make sure the HVPS contacts are clean and spring back when pressed.
Check the connection and continuity of the cable from the fuser exit sensor board to engine board. check the thermistor condition and connection.
Check the thermistor resistance at engine board. It should be from 100k Ohms when cold; it may be as low as 2.3k Ohms when hot, but increase quickly as the fuser cools.
You cannot find a printer or network problem, but jobs still do not print.
If the network card checks out successfully, the problem may be with the hardware or software outside of the network card. Below are some suggestions to the customer for checking hardware and software for possible problems. Refer the customer to the LaserPrinter Network Printer Utility Guide to find the problem.
- Make sure the network protocol you want is enabled from the printer operator panel.
- Verify proper print queue and printer driver configuration.
- Verify the adapter port has been associated.
- Verify correct installation of the software utility.
- Single route broadcast not supported across network bridge, if bridge is used.
- Server problem: check print server installation and configuration using the appropriate system guide to operations.
Network Card 977 Errors
All network card errors are recorded in the error log. If there are errors in the log, POR several times and take the appropriate action for the displayed error code.