Grinding noise When we scan sometimes the scanner makes this loud grinding noise. The rollers have been cleaned and recleaned. The noise comes and goes, but it sounds like something needs oiled. Any suggestions.

Your drum rollers may be going bad (grinding noise) which will sometimes cause the drum to drop slightly, creating a gap where the clothes get caught as the drum rotates. (black streaks)

In my experience, it was the registration roller causing the grinding noise. See http://my.brainshark.com/Phaser-6300-6350-6360-Grinding-Noise-795590408 for troubleshooting video.

Normally Canon scanners work well for long time, Change the pickup rollers for every 250,000 pages and check other rollers for every 500,000 pages. In case you have been scanning documents with quite a good amount of dust, you may need to check at an earlier interval. Replace any worn out roller. Check if the small bearings at the end of each roller is perfect. Clean thoroughly all the rollers, dont use solvents. S. Mohan, Chenna, India

poss nylon gears maybe time for a new one

The noise could be your drum rollers need lubricant or replacement.
When the drum rollers get flat spots on them they will make a bumping/thumping type of noise.
The grinding noise sounds to me like the drum rollers are in need of lubrication.

Try cleaning the guide bar that the scanning head rides on, apply a thin film of lithium grease on the guide bar

The most common problem is that the pulley breaks, you might be able to see it through the glass. looks where the belt goes, and see if the pulley is broken.

also, some people forget to unlock the locking mechanism when the unit gets moved, the locking switch is on the side.

Please open and apply oil on roller rod as some rust have accumulated on it prohibiting it move.

You'll need to replace the pickup roller.

this is a normal thing with scanners i have read reviews about different scanners where the scaners were good prices the only downfall was the noise