(What appears to be) bad transfer on ProC901S

**mrwho** · 02-06-2015

Hello guys.

I've been around this almost all day and still don't know what the hell this is.

Here's an example of a sheet of paper jammed as it entered the fusing unit. The black is pure black and it's supposed to be a 30% solid gray, with no gradient. If I print it in another color, the defect is much less noticeable, but it's there.

Paper.jpg

And here's the latent image on the belt, appears to be perfectly even.

Belt.jpg

No mater where I fiddle, I see no difference whatsoever.

Any suggestions are welcome.

Cheers!

**mrwho** · 02-12-2015

Well, aparently no one has had this problem on this machine.

I've almost changed my mind on the second transfer bet when it appeared to me that the latent image on the transfer belt is somewhat more dense on one side than on the other - but it is so subtle and I was so tired, I can't be 100% sure. But I'm considering all things up to the PTR now.

Honestly, my sense of awe for this machine has turned into contempt now.

**Tonerbomb** · 02-12-2015

do you have the TCRU kits for this machine?? if so it is easy to swap out the ptr unit. Also you could have an issue with the ITB bias rollers making contact with the belt and drum. Most of my uneven density issue though have been with developer units clogging up the doctor gap......

**mrwho** · 02-12-2015

Originally Posted by Tonerbomb

do you have the TCRU kits for this machine?? if so it is easy to swap out the ptr unit. Also you could have an issue with the ITB bias rollers making contact with the belt and drum. Most of my uneven density issue though have been with developer units clogging up the doctor gap......

Thanks for the input.

I never considered the developer units until now because the defect is visible on all colors (maybe except yellow because it is hard to decipher it against the white of the paper), but I'm now willing to consider that maybe they all went bad in the same manner at the same time. Will pop by the customer and take a swab at those doctor gaps.

Things that I already replaced: Transfer belt, 2nd transfer rollers (PTR and ITB)

Things that I already fiddled with that made no difference whatsoever to the defect: 1st transfer rollers (turned them around, changed from one color to another), cleaned ground contacts from all ITB rollers, changed ITB orientation (before replacing with new one), cleaned lasers and laser window glasses, probably more stuff that I can't remember right now.

At this time, if someone tells me it's a leprechaun inside the machine causing havoc, I'll grab a bb gun and go after it.

PS: No kits. The developers are almost new (about 100k).

**mrwho** · 03-30-2015

So the main problem (bad density in the middle) was solved by replacing a (rather expensive) developing unit.

On the other hand, the difference of density between the back of the image (backside of the copier) and the rest is a known characteristic, and there's an SP to compensate for that. Always learning.

Now there is another problem, but I'll open a new thread for that.

I'm getting to the point where I have nightmares at night about this machine...