Oki c712dn and c531dn prints unwanted dots so bad prints!

[FOTINOS]

hello!i have an oki c712dn and it prints unwanted dots reapetedly.
all the cmyk colors.
the space between them is about 3,9cm. to the length of the paper.
i tested all the drivers, pcl, ps, and universal.
also tested glossy, no glossy, heavy, light papers and also labels and they were still there.
also maintenance box clicked, and clean toner before printing is checked.
i stoped a print before the fuse and the dots were already exist.
so the problem is before the fuse.
also cleaned all the drums again and again as i havent anything to lose but they still appear!
please i really need an answer as i have a shop and had the same issue with c531 and it was the reason to throw it away!
the problem is with the drums or with the toners???
(all original and came with the printer.i havent changed anything.they are still new.i bought the printer in march)only 1900 pages printed....

thanks in advance!!!!!!!

 

[OkiTech]

Let me start with: You can not clean the drums, you should not touch them at all! the're being dirtied up and cleaned with every rotation with a silicone blade installed in within imaging unit. Assuming you're rotating the drum in proper direction and it does not come out clean, it means there is a some kind of failure with the imaging unit and drum unit should be replaced. it, also, shouldn't be placed upside-down. Now, to your issue... did you, recently run any labels or anything with adhesive? if you did, particles of a glue could have adhered to the drum's surface and now picking up toner and redeposit it with every turn, or you may have a physical damage to the drum, looks like black color... Don't flip it, tilt it sideways, rotate in proper direction and see where those dots are, if there is some stuck to the drum's surface - you can try to clean it with clean soft rag with alcohol, if there are scratches, then thats it, drum will need to be replaced.