Some printers do measure how much is printed (that is sometimes how they figure a cartridge is used) Still though ink is wated with cleaning cycles, and that costs.

With lasers it is a bit different, as some toner is wasted in the printing process.

In either case, I don't think there is a real reason to know, on a per page basis.

If there wasn't a real reason for me to know, I wouldn't have posted the idea. Anybody else have some comments?

THe real problem is that every page uses a different amount of ink. Printing costs would vary depending on how much ink you were using for every individual page.

That's exactly the problem I'm trying to address. For example, if I have a pesky friend who's always printing stuff on my printer, it should be possible to calculate roughly how much a "particular" page will cost before (or perhaps right after) printing. "That'll be 43 cents."

You can usually find this information in various PC magazines or online hardware reviews of the printers. For example I just bought a PictureMate photo printer that the magazines claimed cost 27 cents per photo.

Indeed the cost of 100 blank photo pages + cartridge guaranteed to print 100 photos is $27.00 (or less).

The printer is $210 and should last 3 years, or around 4000 photos. That's anadditional 5.25 cents per photo. So real cost: 33 cents per photo.

For friends charge them: $0.50/photo + $0.50/minute of your time. Simple solution - they'll go to Walmart/Wallgreens/Supermarket etc.

I've seen commercial software packages that charge departments on a per page basis for internal printing. The only thing it guaranteed was that each dept would buy their own printers, toner and paper - always cheaper.

(and no most printers do not do fine grained flow management of ink - the best I've ever seen had a rough idea of the ink that was left that was off by 5% most of the time. Certainly they don't compute what was used by each page.)

How would you charge people if they were only using say red ink, but the cartridge had three inks that got replaced at the same time? What about the one person who was using blue ink? Then there's dye-sub printers that use a fixed amount of color transfer pages regardless of the image content. It's not a simple problem. Much easier to work with averages per page and ignore the details.