Dots on Konica 7033

[Astermarc]

Hy! My copier have a problem whit a lots of dots. A month ago I change the drum, developer and cleaning blade.Parts count have been reset. In the same period of time I made the inspection of entire machine. Now, after a month and 30 K I have this dots on the page. I have attach 3 picture. Can someone tell me why it apear? All the drum I change, it appear again and again and again.........

I refer at the dots from the center of page (black "cloud") because I know the otherone are from the planten glass. I want to find why they are appear frequently.
If I change again the drum after 30 k this dots appear. First one-two and after I made a lot of copies it became "cloud" like in the picture.

[Luther]

Replace the charge corona wire and grid,is there toner on the charge corona when you take it out? if there is replace the developer unit cover it may be blowing toner onto the charge corona assembly,hope this helps

[RockETop]

Replace the charge corona wire and grid,is there toner on the charge corona when you take it out? if there is replace the developer unit cover it may be blowing toner onto the charge corona assembly,hope this helps

I like this, but also check your fuser roller.

[pepper38_cnd]

Also since it appears to get darker with each copy, I would remove the filter from the fuser cooling fan.

[Astermarc]

On grid, yes I have toner exactly where this dots are on the drum.
The developer unit cover I changed so is not from there.

I change again the corona wire and the grid was new. Every time I made a lot of copies the drum is warming so this dots appear very pronounced.

Why can be the fuser roller?(RockETop suggest this)

[mdm7266]

dots

you may try cleaning or check your exhaust fans, 2 at the left side and 1 at the back-left side. clean the toner vacuum duct if it is clogged under the write unit (laser assy). Proper ventilation reduces drum early deterioration. also check the charge grid voltage adjustment