In the electro-photographic process, the optimum parameters for maintaining image quality vary due to the following factors: fluctuations in humidity and temperature, print mode (image dimensions, P/J), and ageing and degradation of toner, developer, and drum. So the machine needs to determine the best conditions by detecting the development ability (development gamma) of the machine at certain times.
Process control adjusts the image writing conditions for keeping image density steady. In this machine, there are two types of process control as follows:
Potential Control
Controls development potential, which is the gap between the drum potential and the development bias, in order to keep the targeted tone.Toner Supply Control
Controls the toner supply amount for the development unit in order to keep the amount of toner that attaches to the paper steady.
To perform process control correctly, the machine requires "initializing" at the initial installation or at replacement of the development unit, developer, or drum. "Initializing" performs the parameter initialization for the process control based on the behavior before aging of the development unit, developer, and drum.