Question:
We replaced the Magenta toner cartridge and the printer goes through both initialization  and calibration.  Before i replaced the cartridge the yellow toner cartridge had about 2-3 pages of toner.  When the printer completed it’s process the yellow cartridge shows empty.

Does calibrating use toner?
Response:
The HP Laserjet and color laserjet printer uses toner for more than just printing.  On some occasions the printer will use the toner as a lubricant.  Here is a document that explains the different ways the printer uses the toner within the printer.  The document will also explain different ways the process will affect page counts.