View Full Version : Grey background on a Bizhub C353, need help here :)

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Mercutio Norway
08-27-2010, 01:13 PM
First the history:

A customer complained that he experienced paper crash after paper crash on his Bizhub C353, after a quick search I discovered that the roller in the vertical conveyance section was stuck (the wide rubber roller that picks up the paper and feed it to the transfer belt, placed just beneath the transfer belt).
I began the painful disassembly of motherboard etc. to get the right door on the copier off, all of you that has done this know that it's a painful experience that leave you in need of all extra space the customer has, and all the patience you have..
Anyway; the grease that lubricates the copper bushings on either side of the roller had thickened, and was now feeling like tar...
I cleaned the edge of the rollers and the bushings and used my trusty WD40 to lubricate the bushings before assemblying it all together again.

The moment had come to see if I had managed to get it all together again, and the machine worked!!!
But my joy was shortlived, because I noticed that all the copies had grey background (when copying a white sheet), if I copied/printed a document it gave me grey background framing the text...

I started to disassembly the machine again, and checked all the connectors on the high voltage unit (suspecting something was wrong with this...) nothing found...
I tried changing the IU as I noticed it had waste toner on the drum after a test... nothing changed.
I tried changing the high voltage unit, suspecting that I had somehow damaged it during my field service... nothing changed.
I tried to change the 'D max density' to -5 in service mode, and running approx 40 test prints. Nothing changed...

So here I am now, a machine running perfectly but giving me grey background on all copies/prints...

Can anyone please help me, as I am running out of time and patience here...

09-04-2010, 09:37 PM
I have the same problem ....and i didn't disassembly nothing initialy.

Did you solve the problem?

Mercutio Norway
09-04-2010, 11:12 PM
I have a possible solution, it might be the motherboard... Waiting for extra parts as we speak, seem weak pwb-mfc's aren't secluded too the C451 series.
Will keep on posting as I hate loose threads

09-05-2010, 01:53 AM
not recommend disassembling the machine if you do not have the knowledge and information.
Should be more specific. That really disassembly sector? (Roller Timing section).

With respect to the gray background check contact the imaging units K and CMY or parties should check carefully disassembled, check contacts transfer unit + sensor density.

If all this is fine. just make a new stabilizing control, and then perform gradation settings as shown in the installation manual.

10-17-2010, 03:34 AM
anything new?

Mercutio Norway
10-28-2010, 06:03 PM
All my attempts on fixing this copier has failed, nuthin' seem to help.
So sorry guys, I have no news at all :(


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