Whats the deal with lazer printers toner usage? My boss thought itd be a good idea to get a colour LazerJet from HP, its got 4 toner cartridges (black, yellow, cyan and magenta(thats probably obvious)) and he, and I, was under the impression that the idea was black was black and yellow was yellow and orange would be a mix of a couple or the three colours. So the first job for the new printer is thousands of copies of some leaflet my boss (or perhaps a blind monkey) put together in MS Word with 95% black text and one heading in MS Words standard red. So how come all four cartridges show empty at the same time? The guy in the shop who sold him the printer, and hopes to sell £160 of cartridges every month, says this is because all four cartridges are used at the same rate. Depending on the colours the inks from the four cartridges are either applied to the paper or not he wasnt sure where the unused powder went ??!! He reckons this is standard lazer printer tech, is it? If so why do they sell the cartridges in the 4 separate colours?