riso gr3770 drums over inking in centre

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  • bcp
    Technician

    50+ Posts
    • Mar 2008
    • 57

    #1

    riso gr3770 drums over inking in centre

    Use my GR3770 to print envelopes and has started to after about 1000 prints ink bleeds out of the end of master causing ink to get onto pressure roller and ink gets onto back of envelopes. Have used 2 drums and same problem with both. Always use machine full speed and ink turned down to min. any ideas what problem could be. thanks
  • jermyth
    Riso dude

    250+ Posts
    • Mar 2011
    • 439

    #2
    Re: riso gr3770 drums over inking in centre

    You may need a new impression roller or it needs cleaned. To clean it, remove it and scrap it with a metal ruler, gently. You dont want to gouge the roller. Good luck.

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    • bcp
      Technician

      50+ Posts
      • Mar 2008
      • 57

      #3
      Re: riso gr3770 drums over inking in centre

      have cleaned roller and checked to see if it is bulged or expanded in any spots and all is good - still have issue tho

      Comment

      • ddude
        General Troublemaker

        250+ Posts
        • Feb 2009
        • 473

        #4
        Re: riso gr3770 drums over inking in centre

        Many times with envelopes the added thickness causes the master to tear or perforate at the edge of the envelope impression. When running envelopes, you may need to make a new master more often.
        2000 mockingbirds = 2 kilomockingbirds

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        • bcp
          Technician

          50+ Posts
          • Mar 2008
          • 57

          #5
          Re: riso gr3770 drums over inking in centre

          Originally posted by ddude
          Many times with envelopes the added thickness causes the master to tear or perforate at the edge of the envelope impression. When running envelopes, you may need to make a new master more often.
          its not at end of envelope on master it is at the end of the master (where master ends at other end to where master is clamped to drum) and it is only in centre of drum (in line with where envelope is going thru - not at either side )
          thanks for help tho

          Comment

          • ricoh
            Technician
            • Oct 2010
            • 14

            #6
            Re: riso gr3770 drums over inking in centre

            It will most likely be the seal attached to the trail edge of the drum body. The glue perishes after a while allowing ink through. Outside of that, I would be pulling the drum down and re-tapping everything, mainly ink supply. Will the problem occur if doing the same job on standard paper? Need to start eliminating things.

            Comment

            • bcp
              Technician

              50+ Posts
              • Mar 2008
              • 57

              #7
              Re: riso gr3770 drums over inking in centre

              [QUOTE=ricoh;300063]It will most likely be the seal attached to the trail edge of the drum body. The glue perishes after a while allowing ink through. Outside of that, I would be pulling the drum down and re-tapping everything, mainly ink supply. Will the problem occur if doing the same job on standard paper? Need to start eliminating things.[/QUOTE


              yes have tried running letterheads (80gsm bond) same problem after approx 1,000 can see build up of ink. temporary remedy is I sticky tape the trail edge of master and after approx 1,000 run remove tape and wipe excess ink off aand retape and continue.

              what do you mean by re-tapping everything? problem occurs with 3 different drums - could it poss be the ink supply button on the riso itself is not working and is making drums supply max amount of ink continuosly - is there a check code for this?

              Comment

              • jermyth
                Riso dude

                250+ Posts
                • Mar 2011
                • 439

                #8
                Re: riso gr3770 drums over inking in centre

                If you have or get a GR manual and go through the 7 different adjustments for printing pressure. I think some of them have been posted in other threads if you want to look here. That takes care of the machine side of it. Otherwise you need to look into all three drums needing ink blockers replaced and maybe squeege gap and doctor gap adjusted inside. I think it sounds like both too much pressure from the machine and ink blockers.

                Comment

                • Bantams
                  Senior Tech

                  500+ Posts
                  • Jun 2012
                  • 603

                  #9
                  Re: riso gr3770 drums over inking in centre

                  Sounds like the timing is slipping out and the pressure roller is staying in contact with the drum for too long.

                  I dont work on risos (Thankfully) but thats what it usually is on a Ricoh Priport Machine.

                  Comment

                  • mikadonovan
                    Senior Tech

                    Site Contributor
                    2,500+ Posts
                    • May 2008
                    • 2931

                    #10
                    Re: riso gr3770 drums over inking in centre

                    I've gotta ask. Are you using an aftermarket ink? Sometimes issue like this can be resolved by OEM supplies.
                    NEVER ASSUME ANYTHING

                    Comment

                    • bcp
                      Technician

                      50+ Posts
                      • Mar 2008
                      • 57

                      #11
                      Re: riso gr3770 drums over inking in centre

                      Originally posted by mikadonovan
                      I've gotta ask. Are you using an aftermarket ink? Sometimes issue like this can be resolved by OEM supplies.
                      using both types of ink aftermarket & OEM

                      Comment

                      • LA TECH
                        Technician

                        50+ Posts
                        • Sep 2010
                        • 91

                        #12
                        Re: riso gr3770 drums over inking in centre

                        it sounds that your masters are being cut a mil or 2 short there is a way to elongate the master cut but you needs the GR3770 service manual and follow the steps on how to do it I've seen that problem before. like you said it will put a line in the back side of media being run

                        Comment

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