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  1. #1
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    Question Riso GR3750 E33 - Paper Feed Errors and beyond

    E33Paper Jam in the First Paper Feed Area
    Displayed to interrupt the machine operation:
    1) If the Paper sensor has not detected paper while the Position A sensor detects the A position three times.
    Hi all,

    Recently bought a GR3750 and have been going through the steps to get it running smoothly. I'd say about 90% of the time I hit an E33 error when using regular A4 copier stock. If I run cardstock through it's more reliable. Occasionally things just work right and I can get it to crank out a bunch of pages, image is in the right place, impression is clean (but much lighter than it should be).

    When it jams, the paper feeds about 2/3 of the way, you get that and then the error pops up. The drum comes down 3 times, and usually the paper just barely gets kissed by it. Then the error comes up with 1/3 of the page still under the pickup roller, and the other 2/3 under/hanging out from the guide/timing rollers.

    I've been doing the feed/timing adjustments from the RA/GR service manual, but I'm still learning the timing (and terminology!) of each part as I move through.

    I think the jam is occurring between when the guide & timing rollers clamp the page and when the pressure roller comes up to the drum. I do not know if this is due to slippage at the guide/timing rollers, or from the pressure roller and drum.

    notes:
    - I believe the timing is correct. The P-Disk notch on the bottom edge of the sensor, the Pressure Sensor Disc hole is centered on the sensor. Their cams line up with holes as appropriate.
    - The stripper pad is definitely on it's last legs. I'll have a new one in a few days. Otherwise, I think I have the rest of the paper pickup system set right. It's feeding single pages and when the jam occurs it doesn't look like the pickup roller is slipping.
    - I haven't tried adjusting the pressure roller or drum pressure at all, besides setting density from the front panel. I will have a new pressure roller in a few days.
    - I don't have the numbers on me, but masters/copies are both pretty high (IIRC around 10k and 3 million). Not so high that the machine should be scrapped, though. I also have a stack of maintenance receipts/logs to dig through, so some of the more difficult parts that should be replaced once you get into the millions of copies may have already been replaced.

    I think I can get a video sometime this weekend.

    I'd love to hear any advice on what my next steps should be.

    Thanks for any assistance! A lot of posts I've seen so far have been a lot of help already.

  2. #2
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    Re: Riso GR3750 E33 - Paper Feed Errors and beyond

    An update since December:

    I've replaced the pressure roller and stripper pad. I did do pressure adjustments, but that was before I replaced it.

    It feeds paper reliably, but still jams. When it jams, the paper is halfway under the drum with no impression, and the paper just overhanging the ejection belt. Sometimes i can get 10-20 pages out before it jams like that.

    When it jams, the pressure roller is definitely coming up to the drum before paper is there. On subsequent impressions the roller gets ink on the drum and causes a ghost impression on the bottom half of the pages.

    I will check out the timing again.

    Any advice or a lead on a Boston area tech would be awesome. Thanks!

  3. #3
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    Re: Riso GR3750 E33 - Paper Feed Errors and beyond

    I'm having this exact same issue with the 2/3 paper and that sound it makes. Did you ever figure this out?

  4. #4
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    Re: Riso GR3750 E33 - Paper Feed Errors and beyond

    Hi,

    I haven't. I had an update post to this thread, but I guess it was never approved. I replaced the stripper pad, went through the timing again, adjusted pressure, but recently replaced the pressure roller which feels completely different - the old one was pretty mushy.

    Since replacing that, I haven't had a chance to go over the timing again, which I think is definitely off.

    With the bad pressure roller and what I believed was the correct timing, I could get a handful of pages through (the heavier the better) before I'd hit jams at random (sometimes 50+ pages in). Now, with the new pressure roller and same timing as before, I think the drum comes down before the paper is fully under it (making a mess of the roller), then makes an impression on the bottom 1/2 of the paper, then jams with the paper still under the drum.

    I'm waiting for it to be a bit warmer so I can work on the timing comfortably.

  5. #5
    Not a service manager 2,500+ Posts Iowatech's Avatar
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    Re: Riso GR3750 E33 - Paper Feed Errors and beyond

    Most likely the guide roller assembly is at fault. Typically that is because the one way spring that prevents the guide roller from rotating backwards has worn the drive shaft of the guide roller down enough that the roller does rotate backward with the sector gear.
    If you can get an operational guide roller unit, it's not that hard to replace. If not, that machine is probably done.

  6. #6
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    Re: Riso GR3750 E33 - Paper Feed Errors and beyond

    Quote Originally Posted by Iowatech View Post
    Most likely the guide roller assembly is at fault. Typically that is because the one way spring that prevents the guide roller from rotating backwards has worn the drive shaft of the guide roller down enough that the roller does rotate backward with the sector gear.
    If you can get an operational guide roller unit, it's not that hard to replace. If not, that machine is probably done.
    Hello,
    please, excuse my poor english

    Thank you for your help
    I'm also experiencing this problem in my RP3700.
    It happens more with light paper, more in the second pass/face, and at low speed.
    Paper feed ok and get stopped at the second feed section. The drum turns and leave ink in the presure roller, so I have to clean both roller and master (about 10 extra copies).
    Sometimes it doesn't jam, but the printed paper is bent.
    When printing at higher speeds, it seems to run better but I get poor registration, so I prefer to run at minimum speed.

    This weekend the problem arised after printing some 500 sheets, in the second pass as usual. A bit heavier/bond paper seemed to run better, but with some errors too.

    I checked the one way spring in the guide roller (and cleaned a bit the roller itself), and found that works ok when the timing roller is down (no backwards movement). When the timing roller is up, the guide roller can move backwards. Is this a problem?

    I've checked timming, but it seems ok to me, holes almost centered in the cams (maybe I'm wrong, no experience in this)
    I have to confess that still don't understand timing and most of basic operation of my machine...

    Also checked and cleaned paper sensor
    I also tried different settings of the paper cluch off timming in TM with no results, as well as printing with card option and replacing the pad and rollers of the first feed section.

    Based in Iowatech reply, I'm looking for a guide roller.
    Is there anything else I can do meanwhile?

    Thank you

    (not my only problem this weekend; I had to clean ink sensor on a drum and -silly of me- eventually broke two (!) ink tubes trying to get air out. I hope I solved the problem and save the tubes (I'll see in some hours), but my hands are going to be green for months, jajaja)

  7. #7
    Riso dude 250+ Posts jermyth's Avatar
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    Re: Riso GR3750 E33 - Paper Feed Errors and beyond

    FIRST you start your own thread for the GR and RP units paper feed is different.
    SECOND if your having jamming issues when printing on second side only, then I strongly suggest you wait on printing the second side for the ink to dry. Also sounds like your running heavy print and possible heavy ink on lead edge causing paper to stick and the "bent" paper is from the pick off pawl keeping the paper off the drum.

    Good luck.

  8. #8
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    Re: Riso GR3750 E33 - Paper Feed Errors and beyond

    Quote Originally Posted by jermyth View Post
    FIRST you start your own thread for the GR and RP units paper feed is different.
    I'm sorry.

    Quote Originally Posted by jermyth View Post
    SECOND if your having jamming issues when printing on second side only, then I strongly suggest you wait on printing the second side for the ink to dry. Also sounds like your running heavy print and possible heavy ink on lead edge causing paper to stick and the "bent" paper is from the pick off pawl keeping the paper off the drum.
    Good luck.
    I've experienced some of this problems before, I feel this is different. Almost no ink, and far from the edge. I finished to print it in another RP and everything worked ok. Not a single jam.
    Thank you

  9. #9
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    Re: Riso GR3750 E33 - Paper Feed Errors and beyond

    Quote Originally Posted by Iowatech View Post
    Most likely the guide roller assembly is at fault. Typically that is because the one way spring that prevents the guide roller from rotating backwards has worn the drive shaft of the guide roller down enough that the roller does rotate backward with the sector gear.
    If you can get an operational guide roller unit, it's not that hard to replace. If not, that machine is probably done.
    Thanks. I'll have to look at the assembly and spring closer. Do you think it's possible to modify the spring or roller to correct this?

  10. #10
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    Re: Riso GR3750 E33 - Paper Feed Errors and beyond

    Thanks everyone especially Iowatech. The guide roller was definitely at fault - one of the springs was broken and the reverse action was slipping. Someone was asking about the machine and on a whim I did an ebay search and found a used roller assembly at a fair price.


    Replacement was pretty easy, ~30-45 minutes. Unlatch the timing lever, loosen or advance the machine to lower the pressure control motor, and you should be able to get at the screws to remove the roller and it slides out.


    I think the mechanism on these rollers can absolutely be rebuilt, but since my machine is fully working now I'm not in a rush to play around with the old roller. If someone goes down this path you'd want to find a competent machine shop and/or mechanical engineer that's had experience rebuilding similar light machinery.

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