Sharp AR M277 Black Copies

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  • mlbcopiers
    Technician
    • Oct 2007
    • 34
    #1

    Sharp AR M277 Black Copies

    I have a customer with a Sharp AR M277. The copier is used rather heavily. The customer called saying the copies are all black, and the replace toner message was on.
    The exposure is ok. The developer setting showed 169. I had this problem once before with this copier, and did a complete PM and the machine worked fine. I thought that some toner had shorted out the transfer roller. Everything I did today has not corrected the problem.
    I replaced the DV (setting 139), the drum, the toner, and the transfer roller. I even exchanged the tranfer roller door. The drum seems to coat itself, and the developer unit seems to overtone itself. I pulled the transfer roller, and the drum seemded clean.
    Could it be a "bias" problem. I checked all the spring connections to the HV on the copier.
    I am stumped. Please advise. Thank you,
    Tags: act, black, black pages, coat, connections, copies, developer unit, exposure, grid, heavily, hvt, m277, ops, pulled, sharp, sharp ar, shorting, waste toner
    • ZOOTECH
      Senior member of CRS

      Site Contributor
      2,500+ Posts
      • Jul 2007
      • 3383
      #2
      Yes, it could be a bias trouble, but it might be that the LSU is firing all the time, which would fill up the waste toner quickly and give you black copies. A DV adjusting to 169 is pretty high, 139 is closer to normal. How is the DV bias, and have you cleaned the toner sensor (it can be caked with toner causing a misread)?
      Let us know what fixes it, thank you.
      "You can't trust your eyes, if your mind is out of focus" --

        Comment

        • mtech
          Technician

          250+ Posts
          • Mar 2007
          • 307
          #3
          Check your drum ground and main charge. Is the copy actually all black or is there a faint image in the back ground? Main charge could be shorting.

            Comment

            • blackcat4866
              Master Of The Obvious

              Site Contributor
              10,000+ Posts
              • Jul 2007
              • 22865
              #4
              I'm leaning towards primary charge loss. Whether you've got a short somewhere, or an open primary charge contact, or the HVT is not giving you any primary charge, I don't know....

              .....this is all presuming that there is some indistinct image in your black pages.

              If there is no image, then the laser is more likely. I've got to say, though, that its very rare to have a bad laser driver board. Usually only the polygon mirror motor fails and gives a code. =^..^=
              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.
              5) You are the person onsite. Only you can make observations.

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

                Comment

                • MHeon71
                  Trusted Tech

                  Site Contributor
                  VIP Subscriber
                  250+ Posts
                  • Oct 2008
                  • 485
                  #5
                  There is a bulletin on Sharps web site for this problem. Try changing the main charge. They changed the MC unit. The new part # is CHLDZ0035RS57. The last digit has changed from a 3 to a 7 and it is the same one that is used in the AR-M317. They removed teeth from the saw tooth on both ends where the screen grid stops to prevent leaking. I had a customer that had black copies once a month changed th MC and problem has not come back since September.

                    Comment

                    • mlbcopiers
                      Technician
                      • Oct 2007
                      • 34
                      #6
                      I changed the main charge unit, and the problem went away.
                      Thank you for the information.
                      I also ordered the new charge unit.

                        Comment

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