Canon NP6621 - just wont copy !!

[Emjay]

Thanks for all your suggestions about the image quality problem.

The machine has done 310K, which I reckon isn't overworked. The second counter (which I suspect is a PM counter?) is on 60K.

All the mirrors (6 of 'em) are spotless, the transfer roller has been dry wiped, primary charge roller has been cleaned. I've vac'd the waste toner out of the hopper on the drum assembly.

There are a lot of fine lines on the drum surface, which would account for the feint intermittent dark lines running in one direction, but not for voids.
The mag roller is getting evenly coated - the "brush" looks good in fact.

I never thought about the scan rails - they are next on my list. That may well account for the fact that every 5 of so pages, the voids are almost gone.

I think the drum is probably well past its best - its a light purple colour - probably not an genuine Canon part ?

Will let you know how I get on.

Thanks again.
MJ

[remielee]

Hi !

Not done any Canon machines before (mainly worked for KM dealers).

Got a Canon NP6621 which appears to be ready to copy, but just wont !

There are no error codes, the doc feeder is detecting paper size correctly (as it will off the glass as well).

The START key is lit green, but pressing it has no effect.

Before I dive in too deep, am I missing something very obvious here ?

One thing I haven't see yet is the scanner lamp illuminate. On older analogue machines, I would expect the lamp to come on briefly at power up. This machine does a quick scanner lamp shuffle but no light.

I should say that I don't know the history of this machine as it's one we've taken back whilst installing a new one. Looks like it has been sitting idle for a few months. I do have the service manual.

Any Canon experts out there ??

Thanks,

MJ

i think the problem is on the scanner section did you check the lamp if theres a continuity? the cables if was connected properly or if the scanner stock and dosent move check if it was freely moving on the railings

hope it will help you.

[Emjay]

Sigh! Back again for more help! Analogue copiers are just not my thing. :-(

I've checked all I can on this machine. The scanner rails are fine.

Most of the time, the copier produces copies with dark bands across (see pic below - example "A"),
the bands do tend to move around the page, so are not in the same place all the time. They also vary in
thickness from thin (around 4mm) to thick (around 10mm):

NP6612_A..jpg

and then every now and again, mixed in with the poor copies, is a really decent one (example "B") !

NP6612_B..jpg

For an old analogue copier, I reckon the example "B" is acceptable. But why does the machine only throw out a page this good every now and again?

I'm stumped !

[blackcat4866]

It looks to me like a drum ground issue. When the drum coating gets too thin you'll get the appearance of bars crossfeed. The distance between the bars stays the same, but the thickness of the bars can vary from nothing to very wide. =^..^=

[Brian8506]

If this is the same as a 6521 the drum will code out at 40k unless someone changed the drum chip. If that drums been in there a while it may need to be changed. Have you stopped the copier halfway thru the cycle to see what the image looks like on the drum? Is the primary charge roller getting dirty quick?