What causes those horizontal color streaks on my printer's output?

Question

Ever since I acquired it, less than a hundred pages ago, this printer's paper output has featured horizontal bands - the denser the color, the denser the streaks.

The printer is a Canon i-SENSYS MF-8340Cdn.

The original test image :

The same test image, printed and scanned :

The printer's diagnostics tell me that the toner cartridges are full. I see no contamination of any sort inside the printer.

Can anyone tell me what is going on ?

Solution

The 'starter' toner cartridge that came with the printer were defective. I replaced them and the problem simply disappeared. I probably should have started with that...

Comments

[Simon]

It is probably best if you return it as defective.

[CharlieRB]

Looks like dirty or defective ink cartridges. Have you tried new ink cartridges?

[raul]

The integrated toner/drum bits are clean as far as I can see.

[raul]

I'm now hunting for an answer from Canon - I'm not holding my breath. I'll post the answer here if Canon solves the problem before Superuser !

[Lorenzo Von Matterhorn]

dont mess with it; return it as defective.

[raul]

This is a laser printer - so there are no print heads that might get clogged (when that happen on inkjet printers, I wipe them with a moist tissue)... I'll take a closer look at toner-related bits.