KM-4050 poor fill and background

[blackcat4866]

I'm posting this for a pal who is shy. Here's his issue:

It's a KM 4050 that has 380,000 clicks. First service call I see where the background should be white but it looks grey. The blacks do not look solid. I replaced transfer roller and developer unit. The after copies became as they should. Next day, grey background customer said. I replaced drum unit. Again, the after samples appeared as should and looked great. Next two days customer calls grey copies again. I replaced HVU per tech support, looked great till one hour later grey copies. My regional rep thinks issue with the drum. The drum is new. I am not sure what else to try.

My response: It's almost certainly a primary charge or drum ground issue.
On the first trip, when you removed the drum unit to install the new developing unit, you probably re-positioned the primary charge or drum ground contacts. On the second trip, you replaced the drum unit, again with the same affect. On the third trip you again removed the drum to access the HV contacts, again with the same affect.

I would check the primary charge contact on the rear frame and the contact on the end of the primary charge unit. Then I would make sure that the drum ground contact at the front of the drum unit is lubricated with good quality conductive grease. Also check the drum drive coupler on the rear of the drum unit. I know it's counter-intuitive, but lubricate the drive coupler with light oil not conductive grease. The conductive grease will gum up the coupler so that it will not spring back. If you do these things I'll give you a 85% chance of success.

Who else has ideas? =^..^=

[Copystar Tech]

This is a long shot, but back when we first were placing 6030's in the field, we ran into a bad batch of OEM toner that gave the exact same symptoms. Purged the toner from the dev unit and used a fresh cartridge and the problem went away and never came back. Seems to me that we ran into 4 or 5 cartridges of bad toner and never had it happen again. Just a thought...

[blackcat4866]

Thanks C-Tech. There isn't a mention of whether it's generic toner. Thanks. =^..^=

[Venom]

Sounds like a bad drum to me

[tbsoa]

This is a long shot, but back when we first were placing 6030's in the field, we ran into a bad batch of OEM toner that gave the exact same symptoms. Purged the toner from the dev unit and used a fresh cartridge and the problem went away and never came back. Seems to me that we ran into 4 or 5 cartridges of bad toner and never had it happen again. Just a thought...

Thank you. I will check these areas.