Toray Industries, Inc.

Tokyo Industries, Inc.

Yuichi Nakao

Yoshihiro Tamura

Kazuo Ishiwari

Jun Inagaki

Hidetoshi Hara

Hiroyoshi Asada

Hara Hidetoshi

An electrophotographic printer includes: a photosensitive drum; a latent image forming portion for forming electrostatic latent images on the photosensitive drum based on print information; a developing portion for developing the electrostatic latent images using toner; an intermediate transfer drum for receiving the toner images from the photosensitive drum; a transportation portion for delivering a recording medium; and a transfer roll for transferring the toner image from the intermediate transfer roll to the recording medium. A pressure force P.sub.1 between the photosensitive drum and the intermediate transfer drum is less than a pressure force P.sub.2 between the transfer roll and the intermediate transfer drum. P.sub.1 and P.sub.2 may also have the relationship P.sub.1 .gtoreq.P.sub.2 sin.theta., where .theta. is an angle formed between a line through the centers of rotation of the intermediate transfer drum and the transfer roll, and a line perpendicular to a line through the centers of rotation of the photosensitive drum and the intermediate transfer drum. The transfer roll may be separated from the intermediate transfer drum when the image is transferred from the photosensitive drum to the intermediate transfer drum.

Electrophotographic printer and printing method using specific

Printing apparatus and a printing method

An electrophotographic printer method for a printer including a photosensitive drum; a latent image former for forming electrostatic latent images based on the color-separated print information for individual colors on the photosensitive drum; a wet developer for developing the electrostatic latent images successively into toner images for the individual colors using liquid toners of different colors corresponding to the print information and for squeezing surplus liquid toners on the photosensitive drum; an intermediate transfer drum so that the toner images of the individual colors developed on the photosensitive drum are successively transferred to and deposited in layers to form a multicolor toner image; a transportation device for delivering a recording medium; and a transfer-fixing device for transferring to and fixing the multicolor toner image on the recording medium. The method is characterized by the wet developing step including successively developing the electrostatic latent images for the respective colors by a plurality of developing units and increasing the developing bias voltage of the developing unit which has finished developing to a voltage closer to the print area surface potential than the white ground surface potential when changing the developing units.

Electrophotographic color printing method

Growing community of inventors

Otsu, Japan

Yuichi Nakao