Patent ID: 8542376

Claim:
A document processing device, comprising: at least one document processing component operative to perform one or more document processing operations using at least one consumable; a memory storing: a remaining print unit value indicating an amount of print units currently available to enable the document processing device to perform the one or more document processing operations; and a programmable computer operatively coupled with the memory and the document processing component, the programmable computer being programmed to determine (1) a job cost print unit value for performing a document processing operation associated with a given document processing job, and (2) whether the remaining print unit value is non-zero; when the print value is non-zero, the programmable computer selectively causes the document processing component to (1) perform the document processing operation and (2) decrement the remaining print unit value according to the determined job cost print unit value; wherein the memory stores a current page price ratio value indicating the ratio of a number of applied available print units the document processing device will consume to print a color page to the number of applied available print units the document processing device will consume to print a monochrome page; and wherein the programmable computer is programmed to determine the cost for performing a given document processing job in terms of print units according to the color content of the job using the current page price ratio value; wherein the memory stores a total print units used value indicating a total number of print units applied to the document processing device, and a stack including at least one value pair including a page price ratio value and a threshold value, and wherein the programmable computer is programmed to compare the present value of the total print units used value to the threshold values in the stack and to set the current page price ratio value to the page price ratio value corresponding to the highest threshold value that is less than or equal to the present total print units used value.