Work Center 7835 shaded background

[DCStech]

One of our customers is having the background of their scans/copies be gray (minus the borders). The originals do not have any type of shading so we were leaning towards a new CCD (have not installed or tried yet). Then the internal prints started also having this gray background. We thought it might be the application they use but we were able to recreate the issue even printing a page from Microsoft Word. Copied/scanned images are also blurred as well but not the internal prints. We have cleaned the drums/charges. Using a heavier stock paper seemed to temporarily resolve the issue but it has returned. Is there anything else we should be checking for on this model?

202501271232079838.jpg

[xcopytech]

What about prints from diagnostic mode?

[stev0]

I had that problem with an inkjet before, I believe it was a driver related issue. I would try xcopytech's suggestion, if test pages from the printer's panel work then you can rule out hardware issues.

[DCStech]

It still gets the shaded background from diagnostic mode prints as well. I guess it is possible to be a black drum, but I would figure it would cover the entire sheet including the edges if that were the case.

[xcopytech]

Post here some print from diagnostic mode.
Drum related background do not have white margines

[stev0]

Try swapping the drum? Then if bg is a different color you'll know. If not drum I'd try a firmware update. My memory is a bit foggy, but I think I had something similar happen on one of my 7830s once a long time ago and I *think* a firmware update fixed it.

[adriansto]

It still gets the shaded background from diagnostic mode prints as well. I guess it is possible to be a black drum, but I would figure it would cover the entire sheet including the edges if that were the case.

First do a good cleaning of dust, toner, developer inside of of printer especially where the electrical contacts for drums and developers are. Machine filters also clean or replace. LPHs cleanning. After that the so called maxsetup procedure for setupa again the correct voltages on drums, developers unit and toner concentrations. After all this you can think about software reload, nvm changing and so on...
And what is the 'milleage' of developer material? Check HFSI for xerographics components.

[mojorolla]

dc612, print pattern #9 for CMY & K full halftones

[Marcino84]

All Supplies CRU are original ?????? Very important!
adriansto have good advice for you.
First you must be sure where you have the problem - only on copies/scans or only on printings problem?
If problem is on printed pages check drums next transfer belt for contamination and weak cleaning from transfer belt cleaner. If only from scans/copy you must clean all scanner mirrors/glasses.
If nothing better maybe you need print calibration first from admin@touch screen(if available, altalink has ..i don't remember what was on 78xx now) or step by step from diagnostic mode.
But first I think good solution is to replacing one by one cru's and test print Q (drums and ibt belt,cleaner) for eliminate parts.
Good luck!

[DCStech]

Forgive me for not knowing as I am usually a Sharp technician. I know Xerox can be tricky and this is an older model. Is there an easy way to find and install the firmware? I am not having much luck.

[adriansto]

Forgive me for not knowing as I am usually a Sharp technician. I know Xerox can be tricky and this is an older model. Is there an easy way to find and install the firmware? I am not having much luck.

https://www.copytechnet.com/forum/technical-forums/copier-technical-discussion/xerox/1599760-workcentre-7855-totally-shut-me-out

[DCStech]

Sales decided to swap the machine. Customer did not want to pay for parts on this one anymore.