Tokyo Electric Co.

Hideakazu Mori

Yutaka Fujita

The present invention is applied to an electrophotographic apparatus, wherein a photosensitive body charged by a charger is exposed to light emitted from an exposer, for the formation of an electrostatic latent image, and wherein the electrostatic latent iamge is developed by a developer and the image developed by the developer is transferred on a paper sheet by a transfer charger. The transfer charger of the apparatus is made up of a converter transformer, a switching circuit for controlling the excitation of the converter transformer, and an error detector, arranged in association with the converter transformer, for detecting an error voltage corresponding to a transfer voltage. The apparatus is comprised of a separately (or externally) excited converter which outputs the transer voltage from the secondary winding of the converter transformer, an input section from which one of the print density levels that are predetermined stepwise is designated, and a control section for controlling the frequency and duty ratio of a transfer signal used for causing the switching circuit to perform a switching action, in accordance with the print densith level designated from the input section and the error voltage information supplied from the error detector.

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Shizuoka, Japan

Hideakazu Mori