DYNAMIC FEEDFORWARD PROCESS CONTROL FOR ELECTROGRAPHIC MACHINES

摘要

Apparatus by which multiple reproductions can be produced from an original, all reproductions from the same original being of substantially identical quality. An electrographic machine substantially uniformly charges an electrographic recording member to a predetermined initial voltage and imagewise exposes the charged recording member at a nominal exposure level to produce a latent charge image. The initial voltage level and the exposure level are process control parameters of the machine, which also include a biased electrode for controlling deposition of toner to the latent charge image. Signals are produced and stored having values characteristic of (1) the level of at least one of the parameters and (2) the bias voltage level which are associated with a desired reproduction quality of an original. A comparison signal is produced by taking the signal values of the sensed parameters associated with latent charge images of successive reproductions of an original and comparing them to with the stored signal values for the corresponding latent charge images of the same original. The bias voltage level associated with the latent charge image is varied in response to the comparison signal, thereby producing a developed image having substantially the same print quality as that produced by the stored signal values.