Fujitsu Corporation

Yukio Nishio

Kazunori Hirose

Hideki Kamaji

Masae Ikeda

Teturou Nakashima

Masatoshi Kimura

Yoshihiro Tonomoto

Hiroshi Nou

Masahiro Wanou

Yoji Houki

Shinichi Watarai

Hiroshi Kera

Makoto Koshi

Megumi Yasuda

Yasuhiro Tukui

Kazonori Hirose

An electrophotographic recording apparatus includes a photosensitive drum on which an electrostatic latent image can be written, a developing device for developing the latent image of a charged visible image with a one-component developer, and a transferring device for electrostatically transferring the charged visible image from the drum to a sheet or paper. The developing device has a conductive foam rubber roller for entraining the developer to form a developer layer therearound and for bringing the layer to the drum for the development of the latent image, a conductive blade resiliently engaged with the foam rubber roller for uniformly regulating a thickness of the developer, and an electric source for applying electric energy to the blade to electrically charge the developer layer by a charge-injection effect. The transferring device has a conductive foam rubber transfer roller in contact with the drum, and an electric source for applying energy to the transfer roller to give a paper an electric charge having a polarity opposite to that of the charged visible image during a passage of a recording medium through a nip between the drum and the transfer roller.

Electrophotographic recording apparatus using developing device with one-component type developer and having combination of charge injection effect and conductive contact type charger

A developing device using a one-component developer composed of toner particles, which includes a vessel for holding the developer, and a developing roller rotatably provided within the vessel so that a portion of the roller is exposed therefrom and faces a surface of an electrostatic latent image carrying body to form a developing area. During rotation of the roller, the toner particles are entrained by a surface of the roller to form a developer layer therearound, and are carried to the developing area for a development of an electrostatic latent image formed on the latent image carrying body. The roller and the latent image carrying body are reversely rotated such that the surfaces thereof move upward at the developing area. A blade member is provided within the vessel and is resiliently engaged with the roller for regulating a thickness of the developer layer, and is disposed below the roller to prevent a leakage of the toner particles from the vessel at an underside of the developing roller. The roller has an open-cell foam structure such that pore openings or porous cells thereof have a diameter which is at most twice the average diameter of the toner particles. The roller preferably has an Asker C-hardness of at most 50.degree..

Developing apparatus for improving the durability of the latent image

Developing apparatus having leaf spring member for regulating

A cartridge type developer supplier, detachably mounted in a developing device for an image formation apparatus such as an electrophotographic recording apparatus, includes a container for holding a developer and having an outlet port formed therein for discharging the developer therethrough, a paddle rotatably provided in the container for feeding a part of the developer from the container to the device through the port during rotation of the paddle, and a lid movably associated with the paddle so that the lid is enabled to take an initial position for closing the port when the paddle is positioned at a given angular position prior to a commencement of the rotation thereof. The lid is moved from its initial position after the commencement of the rotation of the paddle so that the port is opened to enable the container to feed developer to the device.

Cartridge type developer supplier and developing device formed as

A conductive foam rubber roller is used as a charging roller, developing roller, toner-removing roller, or transfer roller in an image formation apparatus such as an electrophotographic recording apparatus, and comprises a tubular roller element made of a conductive foam rubber material and having a central bore defined by a solid skin layer having an electric resistivity considerably higher than that of a foam structure of the rubber element, and a conductive shaft on which the roller element is mounted and fixed. End sections of the skin layer are removed from the roller element such that the foam structure thereof is in direct contact with the shaft at end sections of the bore thereof. Alternatively, a conductive disc-like member having a central opening formed therein is inserted onto the shaft to be abutted against an end face of the roller element, whereby sufficient electric contact can be established between the roller element and the shaft.

Conductive foam rubber roller used in image formation apparatus such as

A one-component developing apparatus includes a developing roller which holds a one-component developer and feeds the developer to a photosensitive drum, and a developer layer thickness regulating blade. The regulating blade has an edge which is parallel with a surface of the developing roller and the edge regulates the thickness of the developer layer on the drum. The edge is constructed by being machined along a direction in parallel with the surface of the developer roller. The edge of the regulating blade may be either sharp or rounded.

One-component developing apparatus having a developer layer thickness

A developing device using a one-component developer composed of colored fine synthetic resin toner particles, which device comprises a vessel for holding the developer, and a developing roller rotatably provided within the vessel, a portion thereof being exposed therefrom and resiliently pressed against a surface of a photosensitive drum. The toner particles are held by the surface of the developing roller to form a developer layer therearound, and are carried to the surface of the image formation drum for development of an electrostatic latent image formed thereon. The developing device further comprises a blade member provided within the vessel and resiliently engaged with the developing roller for regulating a thickness of the developer layer formed therearound. The blade member is constituted such that a proper regulation of the developer layer can be always ensured.

Developing device used in electrophotographic field

A developing device using a one-component developer composed of toner particles includes a developing roller rotatably provided within the vessel, a portion of the developing roller being exposed therefrom and resiliently pressed against a surface of a photosensitive drum. The toner particles are entrained by the roller surface to form a developer layer therearound and are carried to the drum surface for the development of an electrostatic latent image formed thereon, and a blade member is engaged with the roller for regulating a thickness of the developer layer. A voltage is supplied to the roller to electrostatically move the toner particles from the roller to the latent image, and a voltage is applied to the blade member to inject an electrical charge to the developer layer. When an operation of the device is started, a supply of the voltages to the roller and blade member is carried out after the roller is rotated. When the operation is interrupted or stopped, the supply of the voltage to the blade member is prematurely stopped before the supply of the voltage to the roller and the rotation thereof are stopped.

A developing device using a one-component developer which includes colored fine synthetic resin toner particles. The device includes a vessel for holding the developer, and a developing roller rotatably provided within the vessel. A portion of the device is exposed therefrom and is resiliently pressed against a surface of a photosensitive drum. The toner particles are held by the surface of the developing roller to form a developer layer therearound, and are carried to the surface of the image formation drum for development of an electrostatic latent image formed thereon. The developing device further includes a blade member provided within the vessel and is resiliently engaged with the developing roller for regulating a thickness of the developer layer formed therearound. The blade member is such that a proper regulation of the developer layer can always be ensured. The blade member is pivotally provided within the vessel so as to be resiliently and tangentially engaged with the developing roller for regulating the thickness of the developer layer on the developing roller.

Developing device used in electrophotographic field with a one-component

A developing device using a one-component developer composed of colored fine sythetic resin toner particles, which device comprises a vessel for holding the developer, and a developing roller rotatably provided within the vessel in such a manner that a portion of the roller is exposed therefrom and resiliently pressed against a surface of an electrostatic latent image formation drum. The roller is formed of a conductive porous rubber material so that pore openings appear over a surface of the roller, and the pore openings have a diameter which is at most twice an average diameter of the toner particles, whereby during rotation of the roller, the toner particles are captured and held by the pore openings of the roller to form a developer layer therearound and are carried to the surface of the drum. The developing device further comprises a blade or roller member provided within the vessel and resiliently engaged with the developing roller, for regulating a thickness of the developer layer formed around the developing roller.

Developing device used in electrophotographic field and method of

The present invention is directed to a developing device using a one-component developer composed of colored fine sythetic resin toner particles. The device includes a vessel for holding the developer and a developing roller rotatably provided within the vessel, a portion thereof being exposed therefrom and resiliently pressed against a surface of an photosensitive drum. The toner particles are held by the surface of the developing roller to form a developer layer therearound, and are carried to the surface of the image formation drum for development of an electrostatic latent image formed thereon. The developing device further incorporates a blade member provided within the vessel and resiliently engaged with the developing roller for regulating a thickness of the developer layer formed therearound. The pressures exerted on the developing roller by the phososensitive drum and the blade member, respectively, can be at least partially released.

Developing device with a controllable pressure release for the

The image forming device of this invention is related to a device such as a duplicator, a printer, a facsimile or the like in which a printing operation is carried out by utilizing an electrophotographic recording system and an electrostatic recording system, wherein the device includes a plurality of consumable working parts including at least a developing unit, a drum unit, a fixing unit, and a transfer unit, and the device further includes a unit for integrating the working time of each of the working parts, a memory for storing the integrated working time of each working part, a lifetime setting unit in which a predetermined lifetime of each working part is set, and a generator for generating an exchange requirement signal for at least one of the working parts when the integrated working time of the working part reaches the lifetime of the part set in the lifetime setting unit, whereby an image forming device having a system in which these consumable working parts can be exchanged at correct intervals, regardless of the conditions of use, is provided.

Image forming apparatus having an exchangeable unit exchange timing

A developing device using a one-component developer is composed of colored fine synthetic resin toner particles. The device includes a vessel for holding the developer, and a developing roller rotatably provided within the vessel in such a manner that a portion of the roller is exposed therefrom and resiliently pressed against a surface of an electrostatic latent image formation drum. The roller is formed of a conductive open-cell foam rubber material, and a surface thereof is thermally or chemically treated to prevent a penetration of the toner particles to an open-cell foam structure of the developing roller, whereby a softness of the developing roller can be maintained over a long period. The developing device further includes a blade or roller member provided within the vessel and resiliently engaged with the developing roller, for regulating a thickness of the developer layer formed around the developing roller.

Open-cell foam developing roller

A developing device using a one-component developer composed of colored fine synthetic resin toner particles, which device includes a vessel for holding the developer, and a developing roller rotatably provided within the vessel, a portion of the roller being exposed and resiliently pressed against a surface of an electrostatic latent image formation drum. The toner particles are held by the surface of the developing roller to form a developer layer around the surface, and are carried to the surface of the image formation drum for development of an electrostatic latent image formed on the drum surface. The developing device further includes a toner-removing roller rotatably provided within the vessel to be in contact with the developing roller for mechanically removing the remaining toner particles not used for the development of the image from the developing roller, and a blade or roller member provided within the vessel and resiliently engaged with the developing roller, for regulating a thickness of the developer layer formed around the developing roller. The toner-removing roller is formed of a conductive porous rubber material so that pore openings appear over a surface of the toner-removing roller, the pore openings having a diameter which is at most twice an average diameter of the toner particles, whereby a penetration of the toner particles into the toner-removing roller is prevented.

Developing device having a conductive porous toner-removing roller

In an image forming apparatus, a mechanism is provided between an upper frame and a lower frame, rotatably connected to each other so that the upper frame can be opened for separating a developing unit in the upper frame, closely united with an image forming drum in the upper frame when the developing unit operates, from the image forming drum so as to have a gap as wide as that the developing unit and/or a drum unit including the image forming drum can be mounted or demounted without damaging a cylindrical surface of the image forming drum, when the upper frame is opened for exchanging the drum unit and/or the developing unit.

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Tama, Japan

Yukio Nishio