Thanks, everybody. Good advice, all.

One of the refill sites lists my printer as a model they sell refill kits for. I asked them how they do it. They told me that it is not all over when the cartridge's PC board indicates empty. Instead, when it says Empty, you just click OK. The second or third time you do this, it gives a message telling you that you must be using refills. If you click OK then, the printer will just keep working and no further messages will appear.

We have a black and white laser printer, but rarely use it any more. Most of this usage is for my wife's business as a doula. She prepares instructions and info sheets, and used to go over each sheet with two or three HiLiters. It may not be cheaper, but man, it sure is quicker, to print with highlighted areas in color to begin with!