Controller for controlling stoppage-timing of application of voltage to electro-developing recording medium

摘要

A controller controls a termination time of an application of a voltage to an electro-developing recording medium such that an image can be recorded and developed with optimum contrast. The controller has a power source for applying a voltage to the medium, a transparency sensor for detecting a transparency of the medium, and a differentiator for differentiating a value of the detected transparency. The controller also has a comparator, a determiner, and a stopper. The comparator compares the differentiated value with a predetermined threshold level. The determiner determines whether or not the differentiated value is greater than or equal to the predetermined threshold level. The stopper stops the application of the voltage to the medium when the determiner determines the differentiated value is greater than or equal to the predetermined threshold level.