Konica 7255 reverse side A3 problem

[Guest]

Hello

I have Konica 7255. It prints perfectly A3 in simplex and A4 in simplex and duplex. Quality is more than ok. The problem is when printing A3 duplex. First side is ok, like in simplex, but second side looks like this:



The problem is in the center and on the edge, as you can see above.

What can cause the problem? I think something in fuser unit, but what should I replace? Why simplex and A4 duplex is ok?

Thanks in advance.

[albano]

HI, try adust the coronas and check the drum life, developer......change if necessary....

[Haroldbfix]

I would check charges and check the user paper setting in 36mode to make sure they are set to default. It looks like a drum current issue or bad consumables.

[lookzovt]

Drum and developer is replaced. What does it mean "dust the coronas", how to do it? I will check paper settings.
But why first side is perfect?

[Haroldbfix]

Drum and developer is replaced. What does it mean "dust the coronas", how to do it? I will check paper settings.
But why first side is perfect?

The machine treats the second side differently from the first side.

[lookzovt]

Charging corona wires was replaced, developer also...

[Luther]

Replace the transfer seperator assembly

[lookzovt]

Replace the transfer seperator assembly

Do you mean "Transfer and separation corona unit" or separation corona wires or other parts?

Can it be caused by rollers in fixing unit?

[Luther]

you can try just the wires ,but if you have the entire unit replace it

[lookzovt]

I have no wires nor unit. It's easy to buy wires (it's cheap and available here).
I will ask man who serviced it if he replaced wires (but I think he replaced wires at charging corona only).

[lookzovt]

I would check charges and check the user paper setting in 36mode to make sure they are set to default. It looks like a drum current issue or bad consumables.

All paper user settings are set to 0.