Kyocera Corporation

Toshinori Nishimura

Yoshio Ozawa

Shoichi Sakata

Eiji Ochiai

Yuji Kamiyama

Masayoshi Yamada

An image forming apparatus of non-contact developing method using two-component developer material which is capable of obtaining a clear image free from fogging, ghost and toner contamination. The image forming apparatus has at least one developing unit which includes a developing roll and a magnetic roll, the developing unit develops an electrostatic latent image on a photosensitive body with a toner thin layer formed on the surface of a developing roll wherein a toner thin layer forming region on the developing roll is smaller than a magnetic brush forming region on the magnetic roll. A high resistivity region is adjacent each end of the toner thin layer forming region on the developing roll. A control device controls a developer material replenishment and controls the biasing to the developing roll and magnetic roll.

Image forming apparatus that prevents attachment of toner to lateral sides of the developing roll

In order to provide an image forming apparatus capable of forming a quality image by restricting a distance between a developing roll and a magnetic roll with a simple structure, an image forming apparatus comprises a magnetic rolland a developing rollthat are disposed in parallel with a predetermined distance and a developing unitthat develops an electrostatic latent image on a photosensitive body drumdisposed on the image forming apparatus main body using a toner thin layer formed on the surface of the developing roll by the magnetic roll, wherein a member for holding rotational axes having a pair of openings for holding, which fits and holds rotatably and integrally each of rotational axes of the magnetic roll and the developing roll is provided, the opening for holding of the developing roll being capable of swinging around the axis center of the opening for holding of the magnetic roll.

Image forming apparatus having a roll supporting member

To avoid developing ghost and selective developing without complicating a developing apparatus and to supply surly charged toner to a developing roll while unevenness of images is not generated to obtain stable images for a long time even when continuous printing, a method for developing in a hybrid developing apparatus is provided, which is characterized in that a data amount of each image, which an image forming apparatus prints and a number of paper sheets passed are detected and that an interval of the action of recovering and exchanging a toner layer on the developing roll to the magnetic roll after printing between paper sheets is variably set in accordance with a printing coefficient determined by the data amount and the number of paper sheets passed and further, a method for developing in a color tandem-type image forming apparatus provided with a plurality of the hybrid developing apparatuses for all different colors of toner, which are disposed along the moving direction of a transfer medium of images is provided, wherein after toner layers on the developing rolls of the all developing apparatuses are peeled off toward the magnetic rolls after developing, a thickness of the toner layer of the each developing apparatus is variably controlled at the beginning of developing in accordance with the image consistency of the developing apparatus having a highest image consistency among image data of toner colors.

Method for developing in hybrid developing apparatus

A method and apparatus for image forming includes a hybrid developing apparatus that supplies surly charged toner to a developing roll. The apparatus includes a developing roll that is electrically conductive at least on its surface. The image forming apparatus and the method have a constitution capable of applying an alternating current bias having a duty ratio in the range of 10 to 50% and a direct current bias superposed thereon. The developing roll is directly confronted with a latent image bearing body through an insulative toner thin layer at the nearest region of the developing roll and the latent image bearing body. An independent bias is applied to each of the developing roll and the magnetic roll, and the toner is refreshed by the varying duty ratio of the alternate current bias and the direct current bias after developing.

Growing community of inventors

Watarai-gun, Japan

Toshinori Nishimura