Laser printer prints black perfectly but cyan magenta and yellow very badly

Question

I got a color laser printer that was previously used in an office environment. It's a Xerox Phaser 6100. The black toner gets applied perfectly to the printouts but the colors don't work at all. See the following pictures of sample page and solid color printouts:

At first I suspected that the CMY toners might just be low but the printer status says otherwise:

• Total Image Count: 28982
• Total Page Count: 24249
• Transfer belt Image Count: 28982
• Imaging Unit Image Count: 28981
• Fuser Page Count: 24249
• Transfer Roller Page Count: 24249
• Cyan Toner Life: 67% Remaining
• Magenta Toner Life: 78% Remaining
• Yellow Toner Life: 67% Remaining
• Black Toner Life: 86% Remaining

All the cartridges are original Xerox products.

I printed some cleaning pages from the service menu but to no avail. I also read about redistributing the toner in the cartridges by shaking them but that didn't help either. And then I read that I should clean the drums on the cartridges with paper towels and alcohol. Still nothing.

This is what the drums on the cartridges look like:

I noticed that the layers of toner on the drums of the colored cartridges are very uneven compared to the black one. I don't really know a lot about laser printers but I suppose that is not what it is meant to look like.

My guess is that since only the colored toner is affected it has to have something to do with the cartridges themselves and not any other parts that would affect the black toner as well.

My questions are:

• What exactly is the problem here?
• Why did this happen and why are only the colored cartridges affected? Does this happen when they are not used for too long?
• How can I fix this? (preferably without having to buy new equipment)

Answer 1

Those colour transfer drums look pretty icky!

Apart from a good, careful clean of the printer's insides and transfer coronas (wires/rods) you might only be able to test by substitution. There's no general reason why the colour drums should wear or behave differently from the black; it might be down to someone doing a lot of colour printing onto unsupported stock - for example, thick card or a coated paper. Other possibilities include: the colour toners have been contaminated by a spill from the black one or someone has re-fed previously-printed material back through the printer.

The black sheet you printed seems to look reasonably OK, so the transfer belt is possibly reasonably healthy.

You might be able to clean the colour drums using dry paper towel by carefully rotating the rollers and then rotating them again to re-coat them and see what sort of consistency you get - if the recoat is bobbly too, or it pulls black toner onto the drum (due to contamination between toners), then you may need to seek out a new set of colour toners.