Method and apparatus for charging for printing operations on an electrophotographic printing machine

A method of enabling a self-service printing machine having an external customer interface device to bill for printing jobs which may require a printing machine to perform various types of printing operations comprising the steps of:

• programming different billing rates in the printing machine with the billing rates being a function of the printing operation;
• receiving an enable signal from the external customer interface device, indicating customer credits therein;
• controlling the printing of sheets fed to the printing machine, comprising:
• feeding a sheet to the printing machine;
• printing information on said sheet or leaving said sheet blank;
• determining if said sheet is blank, printed on one side, or printed on two sides to identify a type of printing operation;
• sending a signal to the external customer interface device corresponding to the billing rate amount programmed for said identified printing operation performed on said sheet;
• deducting said billing rate amount from said customer credits contained within the external customer interface device;
• determining whether customer credits remain in the external customer interface device after deducting said billing rate amount from said customer credits;
• disabling the printing machine if no customer credits remain within the external customer interface device;
• and
• sending an enable signal, after each said sheet is printed, from the external customer interface device to the printing machine if credits remain within the external customer interface device;
• and
• repeating said controlling step until printing is terminated.