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04-21-2015, 11:47 AM
i have proplem with konika minolta 751

there is a black shadow on the back just when i print duplex

04-22-2015, 02:33 AM
What have you done so far? =^..^=

04-22-2015, 07:16 AM
Good luck with that. If you don't use good consumables on those machine u are going to have a bad time. Even with good consumables the machine is going to keep you busy.
If they were not so cheap to run i would not even bother with them.

You must calibrate the drum to the correct voltage as per the voltage on the drum flange (only when installing a new drum).

There are good threads if you search for B600/B750/B601/B751.

Common problems on these machines are.

Bad dev bias connection.
Bad mag roller angle.
Bad developer life.
Dirty/bad erase lamp.

Check you life counters
if the drum is over 500K change it.
If the developer is over 100K change it.
If the charge unit is older that 500K service it.
If the dev tank is over 1M change it
The toner collection roller on 500K as well.

Then check the soft switches, set them to default if you don't know the tweaks.
My bet is that its developer related.

Change your drum and developer and set you maintenance counter to 75K for a vacuum service and a web inspection. This way you dev can reach up to 200K.

04-22-2015, 08:30 PM
Thank you very much , the problem solved after replace toner collecting roller

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