Bizhub C258 rainbow corner when using main scanner glass 11x17

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  • ndlovu
    Technician
    • Nov 2013
    • 21

    [CQ] Bizhub C258 rainbow corner when using main scanner glass 11x17

    So I have a unit that when you use the glass and copying/scanning 11x17 you get a rainbow added to the lower right corner. I have cleaned the glass inside and out, cleaned all the mirrors and also the light. I am looking for pointers in which direct to go from here. When testing I also covered the whole top with a blackout cloth just in case some light was getting in. If I do a black/white copy/scan it the produces a black image where the rainbow would be. I have attached examples and I know the rainbow comes out on the lower left but the image is being created on the lower right side of the main glass. Anything copied/scanned via the ADF has no issues.
    Attached Files
  • davidmtupper
    Trusted Tech

    250+ Posts
    • Jul 2021
    • 326

    #2
    Re: Bizhub C258 rainbow corner when using main scanner glass 11x17

    Looks like the scan head is dropping/raising in that corner, check for bent rails.

    Comment

    • Gift
      Service Manager

      1,000+ Posts
      • Mar 2011
      • 2401

      #3
      Re: Bizhub C258 rainbow corner when using main scanner glass 11x17

      Guess the image is also not crispy-sharp if it comes closer to this corner.
      Perhaps the scanner frame is slightly bent/warped.
      You can try and pull the left corner up (or down) with a little bit of force while doing a test copy.

      If the symptome changes you might be on to something

      Comment

      • 4Toon
        Technician

        50+ Posts
        • Mar 2023
        • 90

        #4
        Re: Bizhub C258 rainbow corner when using main scanner glass 11x17

        Lift up on the scan table that is over the internal exit tray. The screws on that scan table can be untightened and then retightened when lifting up on the table. Common issue due to people leaning on the DF on that corner making the whole table slant down and making the rails and the scanner to not be level.

        Comment

        • pepper38_cnd
          Field Service Manager

          Site Contributor
          1,000+ Posts
          • Aug 2005
          • 1076

          #5
          Re: Bizhub C258 rainbow corner when using main scanner glass 11x17

          Maybe have a look at KM Bulletin 11244 See if it may apply?
          Online Store is closed. Chip resetting is a thing of the past! Thank you to all my past customers.
          Now into Ip TV KODI Boxes

          Comment

          • Hansoon
            Field Supervisor

            Site Contributor
            2,500+ Posts
            • Sep 2007
            • 3273

            #6
            Re: Bizhub C258 rainbow corner when using main scanner glass 11x17

            Lift up on the scan table that is over the internal exit tray. The screws on that scan table can be untightened and then retightened when lifting up on the table. Common issue due to people leaning on the DF on that corner making the whole table slant down and making the rails and the scanner to not be level.
            +1

            The entire image is warped. Very likely, the scanner unit where the mirrors and optics is sitting in is slanted. Or otherwise, one of the mirrors is knocked out of position.

            Hans
            " Sent from my Intel 80286 using MS-DOS 2.0 "

            Comment

            • Don N.
              Trusted Tech

              250+ Posts
              • Nov 2011
              • 409

              #7
              Re: Bizhub C258 rainbow corner when using main scanner glass 11x17

              Likely correct on the scan bed being leaned on. I think the slower machines do not have scanner bed frame support adjustment screws. The faster models (C458/C558/C658) have an added steel plate on the left side to loosen, adjust & tighten.

              My opinion is that what got leaned on will get leaned on again, so I'm not pulling the scanner bed up & expecting a recall later. Here's what we've done to fix without getting "chiropractic" with them... see pic with lens screws circled.
              Turn rear screw if rear of image affected, front screw if front of image...
              Turn 1/8 to 1/4 max and write on the plate with a sharpie next to the screw as to direction. EX: 1/8 ccw or .25 CW
              You ca always go back to starting point if you keep track of every turn! It won't take much to see the effect and undo.
              DO NOT GO MORE THAN ABOUT 3/4 TURN TOTAL. This can help with skews from the glass to a small extent.

              bizhub lens adjust.jpg

              Comment

              • Woxner
                Senior Tech

                500+ Posts
                • Jul 2011
                • 805

                #8
                Re: Bizhub C258 rainbow corner when using main scanner glass 11x17

                dont touch the lens screws.....Its one of thing most likley the scan table just needs lifting. This is 99 % of the time. Why the hell would these screws need to be adjusted. They dont move on there own. there was a bulletin on the screw commin loose on scan pully or mirror out of place. both are rare. Tell them not to lay on the DF

                Comment

                • Don N.
                  Trusted Tech

                  250+ Posts
                  • Nov 2011
                  • 409

                  #9
                  Re: Bizhub C258 rainbow corner when using main scanner glass 11x17

                  Originally posted by Woxner
                  dont touch the lens screws.....Its one of thing most likley the scan table just needs lifting. This is 99 % of the time. Why the hell would these screws need to be adjusted. They dont move on there own. there was a bulletin on the screw commin loose on scan pully or mirror out of place. both are rare. Tell them not to lay on the DF
                  Wox. Normally I'd agree with you but I had a tech that's r/b a few hundred of these. We fixed countless skews (that most ppl wouldnt notice unless they scan to a PC & scrutinized the 4 sides parallel on the monitor, but this tech
                  was that critical. He refused to adjust the ADF until the glass scan was perfect. Yes, many could be fixed by lifting the table. The few that could not we got 100% straight with about an 1/8" turn of those two screws. Ppl need to realize its going to affect focus & skew, but if it yeilds the desired result and you are capable of seeing both at all 4 cirners with a very accurate test chart, it's a great fix.
                  More recently weve seen the symptom (just a few times) appear at the cust office which rules out shipping, vibration or shock. Must be customers tap dancing on the scanner, but our samples sent to the FBI shoe recognition dep't have gone unanswered. I can lift the scan table & wait for the next party, or twist those screws and it seems to stay good. Lifting is kinda non scientific & may not stay. Either way gets it done if you're up to it. Red paint is appropriate to ward off the drive by's. Just heed my warning & notate every 1/8" turn cw or ccw. You can always return to home.

                  Comment

                  • Don N.
                    Trusted Tech

                    250+ Posts
                    • Nov 2011
                    • 409

                    #10
                    Re: Bizhub C258 rainbow corner when using main scanner glass 11x17

                    Or just use this new adjustment jig.
                    IMG_20240423_191724_469.jpg

                    Comment

                    • Gift
                      Service Manager

                      1,000+ Posts
                      • Mar 2011
                      • 2401

                      #11
                      Re: Bizhub C258 rainbow corner when using main scanner glass 11x17

                      Originally posted by Don N.
                      Or just use this new adjustment jig.
                      [ATTACH=CONFIG]62384[/ATTACH]


                      Messing around the CCD assy is where the fun starts - my hint: a laserpointer or a tiny keychain LED light placed face down on the DF contact glass is a great help, did a challange once and was able to revice a fully dis-adjusted CCD in ~30 minutes thanks to the laser pointer.

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