Sharp MX 3640N Void areas intermittent

[Ben Around]

Has anyone encountered intermittent void areas on a Sharp MX2640N, MX3140N, MX3640n series machines.

While running (copy mode) 5 pages at a time 2 out of 5 copies will have the void ares.
I tried swapping the black drum unit, it had no effect. Also checked laser unit connections and re-seated the memory. Wall voltage read 120v with a multi-meter.
And I checked the laser glass carefully to make sure there was no foreign objects.

I'm thinking there may be a problem with the line voltage being electrically noisy. Or possible an issue with the laser unit or main board.

MX3640N Void areas.pdfMX3640N Void areas.pdf

Sample attached.
The void areas are intermittent and random, but look similar and occur roughly in the same area of the page.
8.5 x 11 feed long edge first, copy mode from glass. 2 out of 5 test pages will have the voids.

Any thoughts are appreciated.

[mansart]

Re: Sharp MX 3640N Void areas intermittent

I've seen this but can't find my notes on this problem. If memory serves me correct it is something to do with primary xfer.

[Ben Around]

Re: Sharp MX 3640N Void areas intermittent

I've seen this but can't find my notes on this problem. If memory serves me correct it is something to do with primary xfer.

Thanks for the reply. I'll look into that.

[Phil B.]

Re: Sharp MX 3640N Void areas intermittent

Thanks for the reply. I'll look into that.

why is it people ask for help and always leave out info like:

supplies status
weight of media

is paper damp?

[Ben Around]

Re: Sharp MX 3640N Void areas intermittent

why is it people ask for help and always leave out info like:

supplies status
weight of media

is paper damp?

??? really???
Toner cartridges are inserted and at lease 75% full
The paper is 20 bright white hammermill 500 per ream
And the paper is not damp, the relative humidity level in the office is 74.285%

Did that help narrow the possibilities down a little.

The meter is 20,000 B/W, 12,000 color.

[Phil B.]

Re: Sharp MX 3640N Void areas intermittent

??? really???
Toner cartridges are inserted and at lease 75% full
The paper is 20 bright white hammermill 500 per ream
And the paper is not damp, the relative humidity level in the office is 74.285%
Did that help narrow the possibilities down a little.
The meter is 20,000 B/W, 12,000 color.

Ben .. if you are a tech going on a call.. wouldn't you think those bits of info are vital?

75% humidity isn't that low.. most paper makers and machine makers would like to see humidity around 50% so that it IMHO too high. Paper may not FEEL damp but can cause voids.

you never gave the values in OP..

[copiertec]

Re: Sharp MX 3640N Void areas intermittent

Does it happen on just black? From the looks of it I don't think it has anything to do with low ac wall voltage as the rest of the print looks good. It is not repeating which I would think that would eliminate developing unit. It just seems to be in that particular spot. I'm with Mansart on this one and Phil B. Try fresh paper and look at primary transfer belt for indents of some sort. The last picture has me puzzled as it looks as though something is sorting out, but would not put money on it. Try fresh paper then transfer belt.

[ZOOTECH]

Re: Sharp MX 3640N Void areas intermittent

It's been awhile, but I remember that a piece of lint or similar material on the main charge or grid would cause the same symptom.

[Demon33]

Re: Sharp MX 3640N Void areas intermittent

I had this problem once & it was the bushing/spring on the first transfert roller. The bushing is held by 2 plastic clips and one was broken.

Try changing the primary belt assembly for a test if possible

[Ben Around]

Re: Sharp MX 3640N Void areas intermittent

Does it happen on just black? From the looks of it I don't think it has anything to do with low ac wall voltage as the rest of the print looks good. It is not repeating which I would think that would eliminate developing unit. It just seems to be in that particular spot. I'm with Mansart on this one and Phil B. Try fresh paper and look at primary transfer belt for indents of some sort. The last picture has me puzzled as it looks as though something is sorting out, but would not put money on it. Try fresh paper then transfer belt.

Yes, only on black (as far as I can tell). I ran sky shots of each color and could not reproduce the problem.

I've had paper bite me in the behind a few times over the years. So yeah, I wish I would have swapped the paper out, just to eliminate the possibility. But I didn't, so shame on me.

I put a loaner on site and I have the machine in the shop. So I will be looking at it more closely today. It also has an oil resistant squeaky noise in the Doc feeder, so I get rip that apart too.

Thank you everyone for taking the time to respond with suggestions.

[Ben Around]

Re: Sharp MX 3640N Void areas intermittent

I had this problem once & it was the bushing/spring on the first transfert roller. The bushing is held by 2 plastic clips and one was broken.

Try changing the primary belt assembly for a test if possible

Thanks, I'll look at that. I had a brand new primary transfer belt (frontier series) drop the bushings on a color roller last month. They weren't broke, they just fell out and were sitting on the developer unit. I just put them back in and it's been fine.

[Ben Around]

Re: Sharp MX 3640N Void areas intermittent

I've had the machine in the shop for a few days and so far I cannot recreate the void areas.
Environmental? (noisy line voltage), paper? (now spent), loose connection? (cold solder joint) be back to bite me in the a$$? (probably)

At least the doc feeder noise is fixed. Had to remove the paper feed area from the feeder and clean, lube & inspect. It wasn't hard to remove (it looked worse than it was). About 6-8 screws and the whole section comes off. The steps are in the manual, but they only really seem clear after you take it apart.

Thanks to everyone who took the time to reply with helpful comments. I appreciate it.

[daileyrobn714]

Re: Sharp MX 3640N Void areas intermittent

Yes, only on black (as far as I can tell). I ran sky shots of each color and could not reproduce the problem.

I've had paper bite me in the behind a few times over the years. So yeah, I wish I would have swapped the paper out, just to eliminate the possibility. But I didn't, so shame on me.

I put a loaner on site and I have the machine in the shop. So I will be looking at it more closely today. It also has an oil resistant squeaky noise in the Doc feeder, so I get rip that apart too.

Thank you everyone for taking the time to respond with suggestions.

Check your mag roller in the DV unit ...somehow tiny fragments of metal get stuck to the mag roller and that will cause you avoid lines it's really difficult to get it out of there because it's magnetic easiest ways to change it but I have cleaned them before and they have been successful

Sent from my SM-G930V using Tapatalk

[Ben Around]

Re: Sharp MX 3640N Void areas intermittent

Check your mag roller in the DV unit ...somehow tiny fragments of metal get stuck to the mag roller and that will cause you avoid lines it's really difficult to get it out of there because it's magnetic easiest ways to change it but I have cleaned them before and they have been successful

Sent from my SM-G930V using Tapatalk

Good tip, I'll take a look at that before I return the machine next week.
Thanks.
I hope everyone has a great weekend!

[repn1999]

Re: Sharp MX 3640N Void areas intermittent

I had a mx3140 do the exact same thing on black only. turned out to be primary belt...not the unit just the belt itself. looked it over closely and since outside was perfect i cut it in half and found a small scratch through the back surface of the belt. machine has been in field for about 2 years since that issue and it has never came back.