MX4101N Possible main drive issue

[austonrush]

Hello Everyone,

I have a Sharp MX4101N that has a moving misalignment issue, See attachment (The document is 11/17, short edge fed )

Attachment 23116

You'l need to zoom in to see the problem as it surfaces on only certain parts of each page.

This is definitely not a skew issue. I believe the main transfer unit drive gear must be slipping (cracked or worn teeth). Sim 50-20 and 50-22 have been run but as you can see the problem comes and goes on the page. It is not limited to one colour either therefore I've ruled out a drum/photoconductor drive gear issue. I've replaced the drums and the transfer unit but, the problem remains. Has anyone else run into this issue?

I believe this machine is in need a of new main drive assembly. Does anyone bother trying to replace gears inside the main drive assembly or do most of you just replace the whole thing?

Any other opinions on the issue are most welcome!

Thank You

[Akitu]

Have you done a 64-1 or 64-5 to rule out the optics? I find them much better than a scanned test chart for viewing engine problems.

If your primary transfer drive gear has cracked or broken, your 64-5 printout gets a step pattern to it where the colours will not be laid out on the page correctly, offset by roughly 2-4 mm per colour strip, varying by how badly the gear is damaged.

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[blackcat4866]

Are we talking about the smallest font text? Maybe I'm looking wrong, but I cannot pick out the fault, even at 800% Perhaps the scan didn't capture it, or obscured it?

However I can make one of my world famous wild-assed guesses: If you're getting compressions, measuring from the leading edge exactly 24mm, 58mm or 74mm, and only on letter sized paper (not on LTR-R, LGR or LGR), and only affecting black images, you may have a slipping secondary transfer belt. I am to understand that the symptoms for the cracked or slipping primary transfer gear are similar, but I haven't experienced them yet, so I can't confirm the exact symptoms.

Maybe you can take the time to describe the fault in a little more detail? =^..^=

[austonrush]

Thanks for the replies, i appreciate it.

I ran sim 64-1 and 64-5 the issue appears there as well. See below this was printed on letter long edge fed, so NOT letter-r (we're not looking at a skew issue)

Sim 64-5 result.pdf

you can clearly see the boxes do not line up, the k and c boxes start farther to the left. as the printer continues to print and reaches the 30 (scale under the c blocks) the k,y,m,c all line back up again. However the RGB row stays out of alignment in regards to the r,g and b rows above it for the whole page....

On page 2 of my previous scan (last post) you can see it in the numbers counting down the tint %. The magenta is out of alignment from 50 -100 then comes back in. The yellow is out from 10-50 but it does not really show up in my scan of the issue. You can also see how the colour boxes (pg 2) do not line up properly and the colours outlining the edges do not fit properly. it is a weird issue that does not apply to the whole page. On page 1 the same issue occurs but right at the beginning in the words this is a test pt6, pt 8, pt 10 etc. then it lines back up. my initial scan was printed on 11/17

When I print and 11/17 page the issue always represents the same in the exact same spots. If i print a 2 or 3 page print job and then print the same job again and put each corresponding page beside each other they will look identical and show the problem in the exact same spot.

What do you think? an optical issue or a drive issue? The more I look at this the more stumped I am.... LOL

[austonrush]

I also forgot to mention this happens from all trays and all paper sizes.

The problem seems to occur twice per a full rotation of the primary transfer belt. Each time it occurs it shows on the page for about 3-4 inches. I've swapped the primary transfer belt and seen no change.

This is why I'm suspecting a gear inside the the main drive assembly something that would rotate twice for a full rotation of the belt. What is throwing me off is how printing the same print jobs ie my test sample always results in the alignment being off in the exact same spots in that document (I've printed that document 30-50 times and it always is the same), does the primary transfer roller have a home position so it would always start a print job from the same spot on the belt? It's not just one colour that is off either it is all of them at certain times so, I've eliminated drum drive gears as being the culprit.

Argh I'm frustrated time for the weekend!

Thanks everyone!

[Akitu]

Check the main drive gear of your primary transfer belt. A fracture of the inner side of the gear where it meets up with the pin that drives it will give these exact symptoms.

[blackcat4866]

That's a much better sample. Magenta and yellow are mainly affected. Black and cyan seem to be stable. =^..^=

[austonrush]

Check the main drive gear of your primary transfer belt. A fracture of the inner side of the gear where it meets up with the pin that drives it will give these exact symptoms.

Is this an easy check? I'm going to do this tomorrow. Can the main transfer gear be removed from the front? or does the main drive assembly need to be removed?

[Akitu]

Take the belt out, take off the cleaning unit and remove the gear. Same way you would take off the main gear if performing the primary belt maintenance. Inspect the inside of the gear, particularly around the corners, as cracks may not always be blatantly visible.