[CQ] 2090 Reverse Ghosting

[Guest]

I have a Ricoh 2090 that keeps lowering the grid voltage with auto process control to about 850Vdc and the result looks like extreme drum fatigue. It also will not print gray scale. If the user sets the grid bias back to 1,000Vdc every morning it does work without background. I have replaced the drum (3 times) the developer unit, PCU board and the drum potential sensor. This has been going on for about 600,000 copies.

[tcs04]

I have a Ricoh 2090 that keeps lowering the grid voltage with auto process control to about 850Vdc and the result looks like extreme drum fatigue. It also will not print gray scale. If the user sets the grid bias back to 1,000Vdc every morning it does work without background. I have replaced the drum (3 times) the developer unit, PCU board and the drum potential sensor. This has been going on for about 600,000 copies.

Have you checked the resistance of the drum earth? If it's over about 6 ohms when turning you can get some strange compensations in process control and background. Make sure the dicscharge brush on the contact terminal against the drum shaft is clean.