MP4001 Intermittent Dark Background on copies and SC304

[Vioksrall]

Hi guys, Happy New Year To All! I have MP4001 machine that intermittently produces gray background copies around 4-5 pages and it will return to normal. I checked the logging data it logged frequent SC304 (charge error). We replaced all PM parts but still the same problem. Anybody had expereinced this kind of problem? Thanks.

[Ollie1981]

This has been an issue with this engine since the MP4500 and there's plenty of threads already on the forum addressing this fault.

Ignore the SC304 error code, this has nothing to do with charge, this is a well known issue to do with the toner/developer. Which is.. to be frank.. utter rubbish.

Take out the PCU/Dev assembly and split the drum unit from the dev unit, turn the mag roller in reverse to drop the dev brush and I'll bet you any money the mag roller is coated in toner film.

Take the mag roller off and clean the film off (I usually use scotchbrite but everyone seems to have their own method) clean the doctor blade gap and replace the developer (after cleaning the mag roller you'll probably find that the dev is overtoned and you get heavy background and/or toner scattering without replacing the dev, sometimes I've managed to recover it to an acceptable density without replacing the dev, most times it's come in again 2-3 days later for poor copy quality).

If the drum has done more than 150k then you're better doing a full PCU rebuild incorporating the mag roller clean and a vac out of the recycle coil.

[femaster]

Yup, what Ollie said. Clean the mag roller and replace the developer...

There is another recent thread on this same problem. Below is a link to that thread, I posted a few service bulletins in the thread. While the bulletins don't specifically state the 4001, the 4000 is essentially the same machine, only difference really is that with the 4001 they started including the JAVA SD card with the machines.

http://www.copytechnet.com/forums/ri...-light-cq.html