Problem with IO leaks Indigo 5000

Hi.

I have a problem with Indigo 5000 machine.
If i do for example 1000 copies of the same job, machine leaks(i think) oil on part of it. It's not reccurent. It happens every fiew sheets, but what is the most interesting it happens only on one separation - cyan. When I do "Printing Quality assistant" there is leakage only on 50% cyan(sometimes on 100%).

It doesn't metter if I set cleaning station flow on 700ml, 1l or 300ml. Every time the same. Cleaning station is clean, PIP is new, impression and blanket too. I tried to replace BID, but it didn't help.
This shape appears on the front of sheet.

Dose anyone have suggestions or can help me?

 

Change the sponge roller in the cleaning station and it will probably fix the problem.

 

Thank you for reply. It wasn't fault of sponge roller. I finaly made it. If somebody would have the same problem in the future:
There are two rubber covers/spacers located on both sides of cleaning station on roller. They just were not in the right place (gap of the rubber wasn't placed on the metal inset), and oil was overflowing from cleaning station. It wasn'tso hard to find, but i didn't expected so small detail.