J75 line issue

[michel]

Hi,
I'm hoping someone can guide me to the source of a strange issue with a J75.
The machine is printing cards colour front black reverse.
If one sheet is printed it's fine.
J75.jpg
If more than one is printed, the line appears on all the sheets (with varying intensity) EXCEPT the LAST ONE, which is always OK
J75-line.jpg
The images don't show the whole SRA3 sheet, just the first 2/3 of it. The remaining 1/3 has no problems.

So, for example, if I send 10 to print I will get 9 with lines and one perfect one at the end. So only sending one sheet at a time gets good outcome.

The line is magenta. There is a much smaller imperfection where magenta appears to be missing at 128mm before the line in the direction of travel.
For drum errors you would expect 126mm, and it would repeat on the sheet ... that doesn't happen. It's just the two lines.
I've done all the obvious things, replaced the drum, cleaned thoroughly everywhere, but nothing has solved it.

I'd be most grateful if some kind knowledgeable soul could help ....

[Caffeine]

Re: J75 line issue

Hi,
I'm hoping someone can guide me to the source of a strange issue with a J75.
The machine is printing cards colour front black reverse.
If one sheet is printed it's fine.
[ATTACH=CONFIG]52590[/ATTACH]
If more than one is printed, the line appears on all the sheets (with varying intensity) EXCEPT the LAST ONE, which is always OK
[ATTACH=CONFIG]52591[/ATTACH]
The images don't show the whole SRA3 sheet, just the first 2/3 of it. The remaining 1/3 has no problems.

So, for example, if I send 10 to print I will get 9 with lines and one perfect one at the end. So only sending one sheet at a time gets good outcome.

The line is magenta. There is a much smaller imperfection where magenta appears to be missing at 128mm before the line in the direction of travel.
For drum errors you would expect 126mm, and it would repeat on the sheet ... that doesn't happen. It's just the two lines.
I've done all the obvious things, replaced the drum, cleaned thoroughly everywhere, but nothing has solved it.

I'd be most grateful if some kind knowledgeable soul could help ....

My first guess would be that it might be caused by the card stock "hitting" either the registration roll, the BTR roll, or the fuser roll... In other words, the thickness of the card stock is actually causing a slight shock when it hits one of the many pinch points, and whatever is directly on the 2nd BTR transfer roller at that very second, receives a bit of distortion from the shock.

One way to test that theory would be to swap out your card stock for light weight paper. Don't even change the paper settings on the printer or the Fiery, let it think it is still feeding your card stock so you can do the test with all the EXACT same settings. (Thin paper might end up a little overly cooked, but it should be ok.)

If you DON'T see it on the thin paper, but continue to see it on the thick paper, the stiffness and/or thickness of the card stock itself is likely causing the defect, and unfortunately in this case, there is likely nothing you can do.

[michel]

Re: J75 line issue

Hi - thank you so much for taking the time to reply to my post
I was thinking along the same lines but couldn't quite logic it out ... but your hypothesis does indeed explain the behaviour.

I have done a trial with a lighter stock, and as expected, the problem does not occur, which would seem to confirm things.

I have been using the same stock for printing cards for 6+ years, but this problem has only just occurred ... I use that stock extensively so I could really do to find a solution !
Could it be that something has worn ? I'll try a new fuser to start with and report back.

Thanks again.

[jhalfhide]

Re: J75 line issue

As the issue is magenta only, it could be the drum drive has worn enough that your thick stock is causing enough of a wobble to induce this problem. They can wear and cause elliptical travel. Try swapping drum drive with another colour or just replacing

Sent from my LYA-L09 using Tapatalk

[michel]

Re: J75 line issue

Hi - thanks for your reply.

As I said in my original post, I've already tried swapping the drums, but that makes no difference at all.

[jhalfhide]

Re: J75 line issue

Hi - thanks for your reply.

As I said in my original post, I've already tried swapping the drums, but that makes no difference at all.

Not the drums. Drum drive units at the rear of the machine

Sent from my LYA-L09 using Tapatalk

[Caffeine]

Re: J75 line issue

Hi - thanks for your reply.

As I said in my original post, I've already tried swapping the drums, but that makes no difference at all.

He's talking about the motors which drive the drums, not the drums themselves. They are stepper motors with long spikes on them.

If you're comfortable digging into the machine, it is a worthwhile check, however in my experience, when the drum drive motors fail, and they can get work over time and become "sloppy" like his said, the resulting banding is more intense and sporadic. Definitely not consistent. Also, the drums don't come into any contact with the paper or paper path, they only contact the intermediate transfer belt, which then contacts the paper.

The fact that you were able to eliminate the issue with regular paper vs card stock does imply it is the shock.

If the printer has done a lot of card stock, it doesn't necessarily surprise me that it might have been fine and no longer is any more. Gears wear and get "slop" in them.

Identifying where the slip is happening could be a challenge, but my first stop would be trying a new/known good 2nd BTR unit.