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  1. #1
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    Lightbulb Ricoh aficio MP7500, Two side Printing, Low Density on one side.

    Hello, Ricoh Aficio MP7500, after aprox 200 copies/prints, the density is significantly reduced on one side of the sheet when duplex printing, one side printing is ok,

    Developer unit, PCU was changed, tranfer unit changed too but with the same transfer belt ( used ), do you think is the transfer belt ?, single side large run is ok with this transfer belt.

    someone has had this kind of problems ?

    Help please..

    Thanks

  2. #2
    Service Manager 1,000+ Posts fshead's Avatar
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    Re: Ricoh aficio MP7500, Two side Printing, Low Density on one side.

    i am kinda confused..are you saying side one is perfect and the back page is light?
    and if so and you run a test sheet after is that dark or lite?

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    Re: Ricoh aficio MP7500, Two side Printing, Low Density on one side.

    Quote Originally Posted by fshead View Post
    i am kinda confused..are you saying side one is perfect and the back page is light?
    and if so and you run a test sheet after is that dark or lite?
    One side copying or printing is ok, the problem is the back of the page when duplex, if you run more than 500 copies one side ( without duplex ), everything is ok,
    Only back side is light after 200 copies aprox, when the machine is cool the first copies looks good, but after 200 aprox, the problem appear..

  4. #4
    It's not easy being green 1,000+ Posts Cipher's Avatar
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    Thumbs up Re: Ricoh aficio MP7500, Two side Printing, Low Density on one side.

    Yes air flow is often over looked.

    Many times I've seen filters that are completely cogged up with dust.
    For some reason techs don't like cleaning them, or they just don't remember to.

    There are also a couple of fan speed and on-time related adjustments that are meant to help with light copies as well.

    SP 3-990-001 to 1
    SP 2-978-001
    to 1

    I think those SP modes were added with later firmware releases, so you may have to update if they don't show up.
    • Knowledge not shared, is eventually knowledge that becomes lost... like tears in the rain.

    Fully qualified technician for Ricoh - Canon - Sharp - HP - Brother

  5. #5
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    Ricoh aficio MP7500, Two side Printing, Low Density on one side.

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    Re: Ricoh aficio MP7500, Two side Printing, Low Density on one side.

    Quote Originally Posted by mterrero View Post
    One side copying or printing is ok, the problem is the back of the page when duplex, if you run more than 500 copies one side ( without duplex ), everything is ok,
    Only back side is light after 200 copies aprox, when the machine is cool the first copies looks good, but after 200 aprox, the problem appear..
    For clarity, is that 200 copies which would be 100 sheets or 200 sheets which would be 400 copies?

    One thing you might want to try, turn on ID sensor pattern during job, SP 2507-001. Try setting interval, SP 2507-002 to 50 or 100. This should prevent toner fading during long jobs. Also change SP 2201 to 1 for copies that contain a high proportion of black. These are steps I have used on production B/W to prevent fading.

  6. #6
    Service Manager 1,000+ Posts fshead's Avatar
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    Re: Ricoh aficio MP7500, Two side Printing, Low Density on one side.

    I would check that toner recycling unit that sits on top of dev unit.
    they clog and the 2 mylars fall off..
    if developer is old,maybe change out and recalibrate the dev unit..
    if you power off machine and restart does it add toner and get solid black?

  7. #7
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    Re: Ricoh aficio MP7500, Two side Printing, Low Density on one side.

    Quote Originally Posted by fshead View Post
    I would check that toner recycling unit that sits on top of dev unit.
    they clog and the 2 mylars fall off..
    if developer is old,maybe change out and recalibrate the dev unit..
    if you power off machine and restart does it add toner and get solid black?
    Remember the whole developer unit and PCU unit were change, Transfer unit was change but with the same transfer belt,

    If I power off and let the machine rest for a couple of hours, the back side is ok,

    I have order a new transfer belt to make the test, the extrange is , if you run single side the density is ok all the time..

  8. #8
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    Ricoh aficio MP7500, Two side Printing, Low Density on one side.

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    Re: Ricoh aficio MP7500, Two side Printing, Low Density on one side.

    Quote Originally Posted by mterrero View Post
    If I power off and let the machine rest for a couple of hours, the back side is ok..
    When you power it back on once the fusing unit has cooled to below 100 C, Process Control is executed.
    1. Potential sensor is calibrated.
    2. Drum starts first rotation after fusing temperature reaches 140 C.
    3. Readout from the potential sensor is used to adjust:
    • Development bias (Vb)
    • Grid voltage (Vg)
    • Laser diode (LD) power.
    NOTE: This step occurs only if process control is enabled with SP3901 (Auto
    Process Control On/Off Setting). If this SP is disabled, then:
    • Development bias is set to the value stored in SP 2201 001
    • Grid voltage is set to the value stored in SP 2001 001
    • Laser power is set to a fixed value
    4. ID sensor is calibrated (Vsg).
    5. TD sensor is calibrated (Vref).
    NOTE: These calibrations are used to determine toner supply, so it is very
    important that the developer be initialized with SP2963 (Installation
    Mode) at installation and with SP2801 (TD Sensor Initialization) when
    the developer is replaced.
    If during Processor Control it i s determined that toner concentration is low, toner replenishment id then done. Process Control can be ran manually at any time with SP 2962.

  9. #9
    Major Asshole! 2,500+ Posts
    Ricoh aficio MP7500, Two side Printing, Low Density on one side.

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    Re: Ricoh aficio MP7500, Two side Printing, Low Density on one side.

    Good morning.

    I'd like to know how you ultimately solved this, because I'm having the exact same problem on a Pro8100.

    The machine only does it occasionally on the back side of duplexed prints, and I still don't know what triggers it (last time I waited by the machine while it ate through 2 boxes of paper reams without any hint of trouble).

    Also, since it is on the backside of the sheets only, I'm quite sure it can't be anything drum or developer related (because of paper interleaving, it would be needed some great luck and syncronization to hit only those specific pages).

    So, what did you do?

    Thanks.
    ' "But the salesman said . . ." The salesman's an asshole!'
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