Developing device and image formation apparatus

A developing device comprising a developer carrier having a surface carrying a one-component developer thereon, developer control member abutting against said developer carrier to control a thickness of a layer of said developer, and a charge generation device provided downstream of said developer control member, as seen in a direction of a rotation of said developer carrier, and applying electric charge of a single polarity to a developer layer on said developer carrier, characterized in that said developer is charged at a condition that small aerial discharge occurs in said developer layer by an electric field created by electric charge applied to a surface of the developer layer.

An image formation apparatus comprising an electrostatic latent image carrier bearing an electrostatic latent image, a developer carrier having a surface carrying a one-component developer thereon and contacting said electrostatic latent image carrier in a developing portion or facing said electrostatic latent image carrier in a developing portion with a small gap interposed, a developer control member abutting against said developer carrier to control a thickness of a layer of said developer, and a charge generation device arranged downstream of said developer control member, as seen in a direction of a rotation of said developer carrier, and applying electric charge of a single polarity to a developer layer on said developer carrier, characterized in that said developer is charged with a bias voltage having at least a level where a surface potential of the developer layer no longer increases in proportion to an increase of the bias voltage of said charge generation device.

An image formation apparatus comprising an electrostatic latent image carrier bearing an electrostatic latent image, a developer carrier having a surface carrying a one-component developer thereon and contacting said electrostatic latent image carrier in a developing portion or facing said electrostatic latent image carrier in a developing portion with a small gap interposed, a developer control member abutting against said developer carrier to control a thickness of a layer of said developer, and a charge generation device arranged downstream of said developer control member, as seen in a direction of a rotation of said developer carrier, and applying electric charge of a single polarity to a developer layer on said developer carrier, characterized in that said developer is charged at a condition small aerial discharge occurs in said developer layer by an electric field created by electric charge applied to a surface of the developer layer.

An image formation apparatus comprising a developer carrier having a surface carrying a one-component developer thereon, a developer control member abutting against said developer carrier to control a thickness of a layer of said developer, a charge generation device arranged downstream of said developer control member, as seen in a direction of a rotation of said developer carrier, and applying electric charge of a single polarity to a developer layer on said developer carrier, and a printing head including a control electrode having a plurality of holes to discontinuously jet said developer in response to an electrical signal corresponding to data of an image to be recorded, characterized in that said developer is charged with a bias voltage having at least a level where a surface potential of the developer layer no longer increases in proportion to an increase of the bias voltage of said charge generation device.

An image formation apparatus comprising a developer carrier having a surface carrying a one-component developer thereon, a developer control member abutting against said developer carrier to control a thickness of a layer of said developer, a charge generation device arranged downstream of said developer control member, as seen in a direction of a rotation of said developer carrier, and applying electric charge of a single polarity to a developer layer on said developer carrier, and a printing head including a control electrode having a plurality of holes to discontinuously jet said developer in response to an electrical signal corresponding to data of an image to be recorded, characterized in that said developer is charged at a condition that small aerial discharge occurs in said developer layer by an electric field created by electric charge applied to a surface of the developer layer.

An image formation apparatus comprising an image forming body having a surface bearing a developer thereon, and a charge generation device positioned upstream of a position allowing said developer on said image forming body to be transferred to an image holder, as seen in a direction of a movement of said image forming body, for applying electric charge of a single polarity to said developer on said image forming body, characterized in that said developer is charged with a bias voltage having at least a level where a surface potential of the developer layer no longer increases in proportion to an increase of the bias voltage of said charge generation device.