Electro-photographic apparatus having transfer bias control

Abstract

An electrophotographic imaging apparatus includes a toner image holding body, a transcription unit for transcribing the toner image on the toner image holding body onto a recording medium, and a conveyor for conveying a recording medium toward the toner image holding body and transcription unit. A judging device will judge whether printing is of a first page or not and if it is decided that printing is to be performed on a first page, a first measuring device will measure the electrical characteristic of the toner image holding body prior to the feeding of a recording medium and a transcription voltage will be set depending of this measured result. Thereafter, the recording medium will be conveyed toward the transcription unit where the electrical characteristics of the non-printing region on the recording medium will be measured via a second measuring device and the transcription voltage will be further adjusted. If it is judged that the recording sheet is not the first sheet, only the second measuring and adjusting will be performed. In this manner, transcribing of a toner image can always be performed regardless of the kind of paper being used and/or changes in the environment (temperature, humidity) and a high transcribing efficiency can be attained.