Konica C6000 spotty print

[Konica C6000]

Hi! Does anybody know why print the C6000 these spot?

[wjurls]

I'd start by checking/replacing the black drum unit.

[Konica C6000]

I'd start by checking/replacing the black drum unit.

Everything is clean. A cleaned the full transport section (with duplex of course). The drum and the transfer belt are clear. A see that the black drum frame's top has black toner. I cleaned it. But just minimal change. I rotate the paper (A4) and the the machine same printed the spot to the bottom.

[wjurls]

Try swapping the black drum with the cyan and see if the problem moves with it.

[Konica C6000]

Try swapping the black drum with the cyan and see if the problem moves with it.

Ok. I try it, (about 30-40min)

[Konica C6000]

I changed the drum unit and the spot is over. Thanks!


Why do this the black unit?