MP2851 strange black marks duplex only, odd pages, it gets even weirder

[copyaction]

OK customer has mp2851 running 11x8 1/2 duplex black line border around pages.
Only odd number pages getting these weird shadows right at one of the black lines.

Only happens on 11x8 1/2, not 8 1/2x11.
Only happens on duplex.
Only on odd number pages on left side.
happens from adf or glass.
If I turn originals marks move to right side.
Any other pages without black borders run fine duplex no marks any pages.

Replaced drum unit and fuser and problem remained

I was able to run the job 8 1/2 x 11 for them but obviously they want to know why it can't run the other way

see sample:

sample.pdf

[Iowatech]

Re: MP2851 strange black marks duplex only, odd pages, it gets even weirder

Um, this is just a guess, but are the paper guides leading leading from the ITB to the fuser clean? Sometimes toner builds up on them, and if the paper has curled more from going through the fuser the first time it might pick up some toner on the leading edge of side two of duplex copies there. Depending on the grain of the paper that is being used, it might curl more when being fed LEF, so if the paper is being fed SEF those marks wouldn't show up.
Although, when I've seen toner buildup in that area it is usually purple or tan, so this is kind of unlikely. Sorry.

[copyaction]

Re: MP2851 strange black marks duplex only, odd pages, it gets even weirder

This model is b&w
and the marks show up on the same line but in different position and sometimes only one mark.

[slimslob]

Re: MP2851 strange black marks duplex only, odd pages, it gets even weirder

Is the paper being fed long edge first,LEF, or Short edge first, SEF?

[mongo]

Re: MP2851 strange black marks duplex only, odd pages, it gets even weirder

If it does it only on duplex or is it on the bottom side of regular copies. I would replace the transfer roller and turn on transfer roller cleaning (sp 2996 I think) to see if its goes away. Mongo

[copyaction]

Re: MP2851 strange black marks duplex only, odd pages, it gets even weirder

Is the paper being fed long edge first,LEF, or Short edge first, SEF?

11 inch first.

if I feed 8 1/2 inch first no marks anywhere.

funny thing was if I rotated the originals 180 degrees the marks moved from the left side of the page to the right side almost as if it is happening during the scan.

I can certainly try another transfer roller, the machine does only have 69K on it.

[TonerMunkeh]

Re: MP2851 strange black marks duplex only, odd pages, it gets even weirder

At 69k it is due for a PCU rebuild.

[Gift]

Re: MP2851 strange black marks duplex only, odd pages, it gets even weirder

11 inch first.

if I feed 8 1/2 inch first no marks anywhere.

funny thing was if I rotated the originals 180 degrees the marks moved from the left side of the page to the right side almost as if it is happening during the scan.

You can try pc print or internal prints (i.e. SMC lists) to determine if it's a scan related issue or not.

[copyaction]

Re: MP2851 strange black marks duplex only, odd pages, it gets even weirder

At 69k it is due for a PCU rebuild.

replaced with new type 1027 pcu, both do exactly the same.

[copyaction]

Re: MP2851 strange black marks duplex only, odd pages, it gets even weirder

You can try pc print or internal prints (i.e. SMC lists) to determine if it's a scan related issue or not.

I will see if customer can duplex print it from her computer.

No other originals or test pages that I ran, duplexed, would duplicate the problem. Only this with the black border lines does it.

I ran blank pages, counter sheets, plain text pages, all duplexed and set exposure all the way dark to see if I could see a trace of it and nothing, only the pages with the black border lines.

[copyaction]

Re: MP2851 strange black marks duplex only, odd pages, it gets even weirder

tried new transfer roller today, no luck.

[Iowatech]

Re: MP2851 strange black marks duplex only, odd pages, it gets even weirder

This model is b&w

OOPS! My bad, sorry about that!