Pre-paid document processing devices and operating methods

摘要

Document processing devices and methods are presented, in which the device stores a remaining print unit value in its memory that represents the amount of print units currently available to enable the device to perform the document processing operations, and a programmable computer of the device selectively performs document processing jobs for users and decrements the remaining print unit value until the value reaches zero and the device provides for expenditure of print units according to color content and/or coverage levels determined for a given job.