Abstract: A toner cartridge dispensing system is provided which is particularly useful for xerographically plotting documents of above average length, such as engineering drawings. In one embodiment, a modulated electronic input is scanned across a photoreceptor surface. The electronic input is monitored and data bits are counted to obtain a preview of how much information will be required to be developed. The dispensing cycle is controlled to dispense toner based on this prediction. As another feature, the recognition that the amount of toner dispensed from a toner cartridge lessens with each subsequent cycle results in a compensation by weighting the dispensing rate so that the dispensing cycle frequency is effecting increased by a factor consistent with the total number of dispense cycles already accomplished by the cartridge.

Abstract: An automated process and apparatus is provided for establishing the basic xerographic operating parameters for an electrophotographic printing machine. The document scanning means is used in a setup mode to generate test patches of varying density on the machine photoreceptor. The levels are measured and compared to present values stored in a digital controller memory until convergence is obtained along three separate points on the PIDC curve. The controller adjusts the system parameters of charge circuit, developer bias and system exposure in an iterative process and corresponding to the photo-induced discharge curve for the particular machine.