Black ink on sides of paper. They look like roller marks? Can I clean the printer or does it need a new black ink cartridge?

SOURCE: Printer is leaving black ink marks all over paper.

Running cardstock lightly misted with water or dilute cleaning solution through several times can help. Use either the feed button or print using a program that allows you to print blank pages.

SOURCE: toner marks down right side of page

hmmm...sounds like your toner cartridge is truly unhappy. I'd return it if I were you.

no worries..start by getting new driver for that here

SOURCE: Black ink is faint

First I would suggest performing any head alignment functions with your printer's menu to be sure you have the stepper motor feed adjusted properly. Use the paper you are currently printing on for this procedure so that the thickness of that paper is factored in.
If you stil see the banding after doing this, you can use the Advanced Media Control button under Printer Settings in ColorBurst to fine-tune the paper feed adjustment. Print out the "Media Advance.tif" target (located in the ColorBurst/images & Targets folder) to use as a guide. For white bands, you'll need to enter a negative number (to shorten the paper feed).

SOURCE: Black roller marks on right side of paper

Sounds like you have a bad fuser assembly if the drum unit didn't solve the probelm.

SOURCE: dell 926 photo printer will not print black ink.

I'm am having the exact same problem with a new Dell 926!