On Wed, 17 Nov 2010 10:22:12 +0000, Stephen wrote:

I think I was told you could only use refills a couple of times and then
you had to buy a new whatsit, the big thing you pour the toner into. Is
that true? Why is that? Does something wear out?

Yes the cartridge on these smaller and cheaper laser printers also
contains the photosensitive roller that the laser "writes" on. This
can get tired.

I must have refilled it twice now but I must admit since the last time
I refilled it, the print has been grey rather than black. Have I done
something wrong? Or is it that my whatsit needs changing or have I
just bought cheap toner which isn't as black as the real stuff?

Too many variables really, not enough toner is being picked up and
transfered to the paper. This maybe down to properties of the toner
or a "tired" photosensitive drum.

--
Cheers
Dave.