to the imaging electronics signals that will cause an image to be created on a charged photoconductor the method is extremely suitable for use with a cgc 36 that stores and backlogs the documents to be printed so as to electrically collate the pages of each document a typical example for such a cgc 36 is a ram or a disk storage system which can store a number of documents and the number of times each document is to be printed each document may consist of one or more pages of text material the characters which comprise each page can be of any font and the dsdc 34 may include grey scale capability as the cgc 36 receives and stores the text of the documents from the bcd input the dsdc 34 determines how much toner will be required to print each document in one of two similar ways as will be described hereinafter as the documents are printed the dsdc 34 controls the amount of toner furnished for printing these documents so as to assure both that the printer mechanism 12 does not run out of toner and that the developer 20 has not been given more toner than it can handle the dsdc 34 receives from the cgc the number of documents left to be printed this information is needed so that the dsdc 34 can pace itself with respect to the current toner needs of the printing mechanism 20 the dsdc 34 will signal the toner dispenser 24 to supply the required amount of print material to the developer 20 on an incremental basis as stated previously the invention has been described as applied to xerographic.