Minolta Camera Kabushiki Kaisha

Minolta Company, Ltd.

Konica Minolta Business Technologies, Inc.

Noboru Ito

Tamotsu Shimizu

Masayasu Haga

Kanji Nakayama

Tomohisa Yoshida

Wataru Onoda

Narutaka Yoshida

Katsuhiko Takeda

Yoshiyuki Iguchi

Yoshihiro Shojo

Hiroshi Murasaki

Noboru Yonekawa

Kouji Matsushita

Toshitaro Kohri

Hitoshi Kato

Fumio Masuda

Yasuhiro Nakagami

Yoshio Sakagawa

Susumu Mikawa

Hirokazu Yoshida

Eiji Gyoutoku

Eiji Iwasa

An image forming apparatus, wherein the packing density at a closest point where the first peripheral surface and the second peripheral surface are the closest to each other is within a range from 0.3 to 0.4; wherein a maximum magnetic flux density of a principal magnetic pole for generating the magnetic field for development is located in an upstream side from the closest point with respect to the specified direction and at a point where the packing density is equal to or greater than 0.2; and wherein a magnetic flux density of the principal magnetic pole at a point where the packing density is 0.2 in a downstream side from the closest point with respect to the specified direction is equal to or less than &#xbd; of a magnetic flux density of the principal magnetic pole at a point where the packing density is 0.2 in the upstream side.

Image forming apparatus

An image forming apparatus for forming a toner image on a print medium with a developer composed of toner and carriers, wherein when the first distance is longer than the second distance, an average gap between the first peripheral surface and a member that faces to the first peripheral surface in an area with a length of the first distance extending upstream from the closest point with respect to the specified direction is smaller than an average gap between the first peripheral surface and a member that faces to the first peripheral surface in an area with a length of the first distance extending downstream from the closest point with respect to the specified direction.

A two-component developing device using a developer containing toner and magnetic carrier particles. The developing device comprises a housing, a developing roller, a magnetic field generator mounted inside the developing roller, and a developer restricting member, and further comprises a developer guide member providing a developer guide path for guiding the developer to the developer amount restricting clearance, providing a developer circulation path for circulating the developer to an upstream end of the guide member, and providing a communication path for bringing the developer guide path into communication with the developer circulation path, an upstream end of the guide member being positioned above the position of a peak of magnetic flux density of the magnetic pole of the magnetic field generator which is closest to a low-magnetic force area downstream of the low-magnetic force area or positioned upstream of such a position and downstream of the low-magnetic force area. An image forming device in which such a two-component developing device is employed as at least one developing device.

Developing device and image forming device

A hybrid developing carrier, comprising a resin layer formed on an outermost surface, wherein the surface of said resin layer is provided with sites formed of an inorganic compound having basic points or acidic points and sites where the resin forming the resin layer is exposed, a hybrid developing device equipped with the hybrid developing carrier, and an image-forming apparatus equipped with the hybrid developing device.

Hybrid developing carrier, hybrid developing device and image-forming apparatus

In a developing method of exposing the surface of a charged image carrying member to form an electrostatic latent image on the surface of the image carrying member, while conveying a developer containing toners and carriers to a developing region opposite to the image carrying member having the electrostatic latent image formed thereon by a developer conveying member, and applying at least an AC voltage between the image carrying member and the developer conveying member in the developing region, to develop the electrostatic latent image formed on the image carrying member, the relationship among an initial surface potential V0 at the image carrying member, a surface potential Vir at an exposed portion of the image carrying member, a peak-to-peak value Vp-p of the AC voltage applied between the image carrying member and the developer conveying member in the developing region, and a distance Ds (mm) between the image carrying member and the developer conveying member in the developing region satisfies the following condition:

Developing method

A developing device which develops an electrostatic latent image formed on an image-bearing member in an image forming apparatus. The developing device has a developer transporting member for transporting a developer to the image-bearing member, and a rotatable regulating member provided at an upstream side from the developing region with respect to a transporting direction of the developer transporting member for regulating an amount of the developer held on the developer transporting member. The regulating member includes a regulating portion which has a section wherein a distance from a rotational axis of the regulating member to periphery of the regulating portion is not fixed.

Image forming apparatus with member for regulating an amount of

A developing apparatus according to the present invention comprises a rotating developing sleeve, a developer supplying portion for supplying developer to the surface of the developing sleeve, a developer collecting portion for collecting the developer from the surface of the developing sleeve, the developer collecting portion and the developer supplying portion being vertically aligned, a pair of magnetic poles fixed in the developing sleeve, the pair of magnetic poles forming a triangle area which is surrounded by tangent lines at points where the magnetic poles have the maximum magnetic force, and a wall positioned between the developer supplying portion and the developer collecting portion, the edge of the wall being positioned in the triangle area formed by the pair of magnetic poles.

Developing apparatus and image forming apparatus

A developing method for developing an electrostatic latent image at a developing region includes preparing a developer containing toner particles and carrier particles which has an inherent resistance value of 1.times.10.sup.7 .about.1.times.10.sup.12 .OMEGA.ocm under an electric field of 500V/mm, magnetic force of 600.about.2300 G, and a mean particle size of 10.about.30 .mu.m; regulating a quantity of the prepared developer on a developer transporter within a range of 0.7.about.5.0 mg/cm.sup.2 ; transporting the regulated developer to the developing region; and applying an alternating current voltage between the developing region and the electrostatic latent image to generate an oscillating electric field therebetween in order to supply the transported developer to the electrostatic latent image.

A developing device having a developing sleeve opposed to a photoreceptor, and a developer transport portion adjacent to the sleeve. The developer transport portion is divided into first and second portions by a partition, and the developer is circulated between the first and second portions. A fresh toner is supplied to the developer in the second portion to be transported to the first portion while being mixed, and thereafter is supplied to the sleeve along an axial direction of the sleeve in the first portion. The second portion is provided with a transport member by which the developer is transported at an upstream side of the second portion with respect to the developer transport direction in the second portion with a speed faster than the toner supply speed and the transport speed of the developer at a downstream side of the first portion with respect to the developer transport direction in the second portion.

Developing device for mixing and supplying developer

A charging device with a plate-like electrode having a plurality of protrusions, the charging device having a cleaning device including cleaning members which are positioned bilaterally to the electrode and grip the electrode therebetween to clean. The cleaning device cleans the electrode while the cleaning members slide on a guide formed along the electrode, or the cleaning device cleans the electrode by griping the electrode by the cleaning members which are positioned along the electrode.

Charging device having a plate electrode and a cleaning device for

An image forming apparatus has a toner recycling mechanism for effecting toner recycling. The image forming apparatus includes a developing unit accommodating developer for developing an electrostatic latent image formed on the surface of a photosensitive member, a cleaning unit for recovering developer remaining on the surface of the photosensitive member after development, and a toner recycling assembly. The toner recycling assembly includes a developer conveyor pipe through which the developer recovered by the cleaning unit is conveyed to the developing unit for recycling of toner contained in the developer, and also includes a developer supply or transport pipe for supplying the developer accommodated in the developing unit to either the developer conveyor pipe or the cleaning unit.

Image forming apparatus having a toner recycling mechanism

A magnetic carrier is disclosed which is for use in electrographic developing method which effects development of an electrostatic latent image with a magnetic developer at a developing region by rotating a developing sleeve incorporating a magnet therein thereby causing the aforementioned magnetic developer composed of an insulating toner and a magnetic carrier to be transported to the aforementioned developing region. This magnetic carrier is composed preponderantly of fine magnetic powder and binder resin and is possessed of specific properties, i.e. 2000 to 3000 gasses of magentization in a magnetic field of 1000 oersteds, 60 to 250 oersteds of coercive force, and not less than 10.sup.12 .OMEGA..cm of electric resistance.

Magnetic carrier for electrostatic latent image development

A developer for use in developing an electrostatic latent image according to electrography comprises a mixture of a carrier and a toner having a property of being triboelectrically charged to a positive polarity when held in frictional contact with the carrier. The toner includes a binders which is a thermoplastic resin having a Lewis acid-functional group.

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Kawanishi, Japan

Noboru Ito