Riso SF9350 EII paper wrap around pressure roller

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  • Philemon63
    Junior Member
    • Jun 2025
    • 2

    #1

    Riso SF9350 EII paper wrap around pressure roller

    Hello everybody, ๐Ÿ˜€

    I have been printing 60 gsm carbonless paper for 15 years on a Riso MZ770 without any problems, except with CFB, which is always more difficult to feed.

    Almost a year ago, I replaced the MZ with a SF5350 EII that was practically new (from 2021 / barely 1 million cycles).
    In the early months, carbonless printed just as well as on the MZ.

    But since about 3 months, when I print 60 gsm NCR it goes well at the beginning, but after 1000 or so printed sheets, the paper start to wrap around the pressure roller (whether CB, CFB, or CF) and causes a jam (with a characteristic โ€œscrapingโ€ noise). As printing progresses, these jams become more and more frequent, to the point of occurring every 10 sheets or so, even when the speed is set to minimum.
    I never saw that on the MZ !
    Of course, when this happens, I try to clean and deglaze the pressure roller with alcohol, but it doesn't make any difference.

    Is this a sign of a malfunction/worn part?
    Should I deglaze with a more suitable product (which one?)
    or something else?
    Thanks for you help
  • 20gaugeO/U
    Senior Tech

    500+ Posts
    • Feb 2009
    • 554

    #2
    I wouldn't use alcohol on any of the rubber parts, it will dry out the rubber. If there is a layer of ink/paper dust on the imp roller scrape it off with the backside of a razor blade and then use simple green on it and roll it on scratch paper to get any residual liquid off it. That being said the imp rollers have gotten much smaller than what they once were. Might just have to buy a new one and see since it is around a million on it. Check that the separation fan, sep finger pump and suction fans are all doing their jobs to get the paper to exit properly.

    Static building up where you are at??? Get some anti-static spray or different brand of NCR paper to test

    Comment

    • jermyth
      Riso dude

      250+ Posts
      • Mar 2011
      • 440

      #3
      RISO has a press roller specifically designed for "paper coated with chemicals". Part # 046-75088, I have not had to order one yet. See what your local RISO dealer can do for you.
      Good luck.

      Comment

      • Philemon63
        Junior Member
        • Jun 2025
        • 2

        #4
        Thank you jermyth and 20gaugeO/U for your advice

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