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Thread: Blue Bubbles

  1. #1
    Master Of The Obvious 10,000+ Posts
    Blue Bubbles

    blackcat4866's Avatar
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    Blue Bubbles

    Yeah, yeah, ... primary charge shorting for cyan. It's a Saturn KM-250ci. Sorry I didn't save any of the samples.

    But here's the thing: It's had three cyan drum units, and it goes away for a while each time. Then I noticed that most of the screws were stripped out on the toner hopper assy. It's no wonder since it's been off/on about a zillion times in the last 9 years. So I re-tapped the holes 10-32 (about 4.5mm if there was such a thing) and installed 5 new 10-32 screws. The theory is that I would get better drum ground contact with the hopper pulled snug up to the frame (not just one screw at the left). I also used some conductive grease at the drum grounds.

    Two weeks later and I'm back. Same blue bubbles. Cyan gradations of 15% or less are blank on my test pattern. So just for kicks I swapped cyan and magenta drum units. Cyan instantly filled in to 40% fill on my 15% pattern (very heavy fill). The first calibration made it worse, almost 60% fill for my 15% pattern. The second calibration brought it around to what I'd like to see: 15% fill. I expected image anomalies to move to magenta, but that didn't happen.

    Self-calibration is clearly compensating for something with the cyan drum/primary charge ... but what exactly? I left with mostly perfect images for a Saturn, but I don't expect it to hold.

    I think both the customer and me want this machine to retire. =^..^=

    If you'd like a serious answer to your request:
    1) demonstrate that you've read the manual
    2) demonstrate that you made some attempt to fix it.
    3) if you're going to ask about jams include the jam code.
    4) if you're going to ask about an error code include the error code.


    blackcat: Master Of The Obvious =^..^=

  2. #2
    Senior Tech 250+ Posts
    Blue Bubbles


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    Re: Blue Bubbles

    Have you swapped out the DV unit? We have had a few cases where something[?] seems to be adhering to the DV roller causing a build up of toner on the DV roller and causing blotches in the copies/prints. Simply cleaning the DV roller with a clean cloth has solved the issue. When cleaning the DV roller you can see that there has been a substance that has adhered to the roller causing an excessive build up of toner on the DV unit roller that gets transferred to the copies. We only use OEM toner so have not isolated why it happens. Rotating the DV unit backwards from it's normal rotation highlights the areas that have the toner build up. After cleaning the affected area the blocthes/bubbles disappear. Just a thought.


  3. #3
    Master Of The Obvious 10,000+ Posts
    Blue Bubbles

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    Re: Blue Bubbles

    Quote Originally Posted by Santander View Post
    Have you swapped out the DV unit?...
    I didn't mention that? Sadly yes, that was with the first drum. =^..^=

    If you'd like a serious answer to your request:
    1) demonstrate that you've read the manual
    2) demonstrate that you made some attempt to fix it.
    3) if you're going to ask about jams include the jam code.
    4) if you're going to ask about an error code include the error code.


    blackcat: Master Of The Obvious =^..^=

  4. #4
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    Re: Blue Bubbles

    I would test it with new dev motor cmy and cleaning motor cmy. Remember that big old bulletin where you had to measure resistance on those >.<


  5. #5
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    Blue Bubbles


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    Re: Blue Bubbles

    Since you have replaced the DV/Drum[s] and the problem is centered around the cyan have you tried the transfer belt? You could have a bad cyan transfer roller in the belt, though this would not explain why it disappears for a while after the drum is replaced. Are the blue bubbles on one side or are they across the page? I also assume that when you say bubbles that there is an outline in cyan and the center is void of the cyan. A blistered transfer roller in the belt could cause this I suppose though I have never seen this. It could be worth a try.


  6. #6
    Master Of The Obvious 10,000+ Posts
    Blue Bubbles

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    Re: Blue Bubbles

    Quote Originally Posted by Santander View Post
    Since you have replaced the DV/Drum[s] and the problem is centered around the cyan have you tried the transfer belt? You could have a bad cyan transfer roller in the belt, though this would not explain why it disappears for a while after the drum is replaced...
    Have not tried the primary transfer belt yet. It does seem to wear out that left front bushing on the belt assy, second time in 100K. I've seem it before, but not that quickly. (On Saturn and VoyagerE ... naturally, since I've still got a few spares I've scavenged just for this purpose.)

    Quote Originally Posted by Santander View Post
    Are the blue bubbles on one side or are they across the page? I also assume that when you say bubbles that there is an outline in cyan and the center is void of the cyan...
    Flattened ovals in a row crossfeed, and all other cyan fades out on those pages. Each bubble has a crisp outline with 15% cyan fill inside.

    Quote Originally Posted by Santander View Post
    A blistered transfer roller in the belt could cause this I suppose though I have never seen this. It could be worth a try.
    I've seen primary transfer roller shift errors a few times on Saturn, but they code out ... and were addressed a really long time ago with changes to the belt assy.

    For now I'm holding my breath that it stay gone. Thanks for the ideas. =^..^=

    If you'd like a serious answer to your request:
    1) demonstrate that you've read the manual
    2) demonstrate that you made some attempt to fix it.
    3) if you're going to ask about jams include the jam code.
    4) if you're going to ask about an error code include the error code.


    blackcat: Master Of The Obvious =^..^=

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