Sharp Mx4501 Print Qualtiy Defects

[Jaws]

I am getting some nasty black smudges on prints. Not the same shape each time but close and it doesn't happen each print. Happens in the middle of the page/printer. I have attached 3 print quality defects images to help you get a better picture of what is happening.

I think it must be a timing issue. The paper must be buckling or sticking once in awhile.

All comments are welcomed. Off topic or on topic.

[blackcat4866]

I'm thinking that you've got a primary transfer belt cleaning problem, but there may be more to it. While you're replacing the primary transfer cleaning belt blade and lower seal also check that all the transfer drive gears are intact, There may be a nick in the belt, or one of the edge 'ridges' may be coming loose and snagging at the cleaning blade.

The two conclusive features of your samples are that the fault only occurs once in an 11x17 image (transfer belt diameter is ~3ft), and that the color of the fault is between purple and brown (the color of transfer waste toner). If this was a drum cleaning fault it would re-occur at ~4" intervals and would be of a single color (CMYK).

Thanks for the samples. That makes diagnosis easy. =^..^=

[NCArt]

I agree with blackcat.....it is a primary transfer belt cleaning issue. Along with what he said, check the units auger coil to make certain a bit of paper/label didn't get caught in it.

[wazza]

You most definitely have a Primary Transfer Belt Unit problem. I see this all of the time. Exactly the same samples too.

What is happening......

The belt is sticking to the main drive roller within the belt unit. As is sticks to the main drive roller, for a split second it passes under the cleaning blade. You need to replace the Primary Belt Unit or fit the belt kit as a refurbishment. If you do this, you will need to do a very thorough clean of the main drive roller within the belt unit (as well as the transfer rollers). Before you fit the cleaning unit to the belt unit frame, manually turn the belt in its normal rotating direction. If you see the belt sticking to the main drive roller for a split second longer than it should as it rotates around the roller, you have not cleaned it enough.
Sometimes you will need to clean the main drive roller with some alcohol or even fine sandpaper to remove the sticky film that develops on the main drive roller. Its a very common problem as the belt nears the end of its life.
If you can get the Belt Unit as a complete unit, go for it. Its alot easier & quicker.

[Jaws]

I did just recently change the transfer belt and cleaning blade. The large 1st drive roller did look worn and all the transfer roller were sticky. I clean the transfer rollers and they came back silky smooth. The large roller did not look like it was clean-able, so I left it alone. I guess that was my mistake.

And it makes sense that it is sticking and causing the problem.

Thanks to all that helped.