This machine has been running fine for 2yrs. Latest firmware has been updated. All of a sudden we noticed that their quarterly volume stayed the same (32k-38k) but instead of ordering 2 toners each quarter (which have a 20k stated yield), they're now ordering SIX toners each quarter (for less than 40k blk impressions).

The black maintenance kit is almost to yield, and copies were very dirty with a lot of background. But, I have a hard time believing an extra 4 toners would be sucked by the copier simply because of dirty copies.

Any ideas?

Time to replace the black developer and/or drum. If the kits are almost to yield, then just install the kits.

Forget what you learned in school about Developer having little jagged points and after a time they where down and now your toner can no longer find its way. The truth is that the developer becomes covered with the plastic from the toner after time and loses its conductivity hence it adds more toner to compensate for this condition. So Chris L hit the nail right on the head when he says to change you DV unit.

there is a bullitian out for that isue you have to change a simulation for toner amt. it is set to high, check it after updateing firmware to current levels

Is there an update for the problem? What fixed it?

id like to know as well, I have one using way too much black.