I have cleaned the drum but my printer won't work because it keeps saying Dust on Drum. do I ned to replace the drum?

If you have a knowledge in disassembling the drum assembly unit then do it their you can see some other parts to be cleaned but be careful for these are sensitive parts.
Steps:Carefully remove the lock both ends, then pull it up and start cleaning inside using an artist brush you can also remove each parts inside if yuo want to individally clean and see to it no toner powder left in the dust collector and assemble again with extra care. Good luck
Note: Dont use brushin OPC drum, best soft cloth instead

open the cover, press clear back(or options)
it will say replace drum? say yes

If the drum is used up you open the front door and press menu or options and tell it it's a new drum, otherwise you clean the metal contacts on the sides of the drum and inside the printer, and run the blue tab back and forth about 20 times. If still drum error you may have a bad power supply.

Dear sir you see properly drum unite has a drum image sensor its demage so you change your copier drum unite, thanks.

Yes some of dust have your printer drum unite.Open drum and clean it then solve your problem.

The drum is part of the toner unit. Check the skinny glass under the drum/toner unit when you pull it out and make sure it is clean! Also try gently blowing air on the entire unit (drum)... I say gently because when you hit the right spot...toner is going to blow everywhere, so you might want to try thin one outside.

Yes, you should replace the drum unit if you have not done so. You may have a broken corona wire or drum. However, keep in mind that you will need to reset your machine after changing the drum unit. If after replacing, you still get the same error, you may have a problem with your machine properly sensing your drum unit.

In the box with new drum is manual how to reset this, however, will not show solution for this particular model. So you ned:

1. Open cover (as to replace drum or toner). On display you will get "Cover Open"
2. Press right arrow under LCD display.
3. Press 1 (digit one) on keypad.
4. Close the cover

Done.

Dust on drum is an issue with the corona wire. Use the blue tab on top of the drum unit. Slide it back and forth 10+ times and this should correct your issue.

Good luck!

Dust on drum refers to as you correctly stated the wire, it carries a electric charge that transfers the image. If the wire gets contaminated the electricity dont flow right so dust on drum is desplayed, you drum cart is faulty, they are not repairable items, go buy another then claim new/old one as faulty from them. Um aH.