Minolta Company, Ltd.

Akihiro Kawasaki

Tamotsu Sakuraba

Koji Uno

Hirokatsu Shimada

Eiji Gyotoku

Hiroshi Toda

Tetsumaru Fujita

Minoru Wada

Ichiro Demizu

Hiroshi Goto

Yoshihiro Fukuhata

Masashi Yamamoto

Hitoshi Saito

Hiroyuki Maeda

Shinichi Takemoto

Hitoshi Sekino

Yoichi Fujieda

Masami Eda

Masataka Yagi

Yasutsugu Takesue

Hiroaki Umemoto

The present invention relates to a developing device for developing images formed on an image carrier. The device is capable of regulating toner amount such that the amount of toner conveyed by the toner control to the developing area is reduced, as well a appropriately changing the carrier.

Developing device comprising a regulation member having at least one bent part

A developing apparatus with a developing roller for conveying toners held on its surface to a developing area opposite to an image carrying member, the surface of the developing roller being moved upward from below in the developing area; a regulating member for regulating an amount of the toners to be conveyed to the developing area by the developing roller; a plate-shaped charging member for charging the toners; and a voltage applying device for applying a voltage to the charging member.

Developing apparatus comprising developing roller that is rotated upward from below in developing area and image forming apparatus using the same

A conductive contact member,is disposed to come into contact with a developer carrying member,at the upstream side of a developing region,with respect to the developer conveying direction. Voltage applying members,and,are also provided for applying the developer carrying member,with a predetermined direct voltage as a developing voltage, applying the contact member,with a direct voltage which has the same polarity as the developing voltage and has an absolute value larger than the developing voltage, and applying between the developer carrying member,and the contact member,an alternating voltage. A ratio t,/t,of a time t,for applying a voltage of absolute value larger than that of a center voltage of the alternating voltage to a time t,for applying a voltage of absolute value smaller than that of the center voltage of the alternating voltage satisfies a relation of t,/t,>1.

Developing apparatus for developing an electrostatic latent image on an image carrying member

A color image forming apparatus, with image forming units configured as cleanerless, whereby the printing speed and the size reduction can be enhanced while maintaining a high image quality, and characteristics with respect to the environment are improved. The color image forming apparatus includes a plurality of image forming units serially arranged in a straight line. Each image forming unit includes an image carrier, an electrostatic latent image forming device for forming an electrostatic latent image on the image carrier, and a developing device for forming a toner image by applying toner to the electrostatic latent image. The color image forming apparatus further includes an intermediate transfer member to which the toner images from the plurality of image forming units are sequentially transferred in a superimposed fashion, and a transferring device for transferring the superimposed toner images from the intermediate transfer member to a recording medium. At least one of the image forming units is configured as a cleanerless image forming unit, having a developing device of a jumping development system. The cleanerless image forming unit includes a toner holding device for temporarily holding residual toner that remains on the image carrier after transfer of the toner image to the intermediate transfer member, and discharging the held residual toner at a predetermined timing.

Clearless color image forming apparatus

The developing apparatus has: a development sleeve; a supply roller; a toner hopper; a stirring member; and a partition member. The partition member and a regulating blade form a space. The supply roller supplies toner to lower part of the space. Thereby, toner present in the proximity of the development sleeve circulates smoothly. Therefore, the following situation will be prevented: 1) since same toner particles are repeatedly stressed by regulation of the regulating blade, toner particles crack; 2) cracked tiny particles of toner melt and adhere to the development sleeve; or 3) the regulating blade gets stiff due to the cracked toner adhering thereto. Further, since constant amount of toner is always collected within the space, appropriate pressure of toner is applied at the regulating position when the regulating blade takes toner into the space.

Developing apparatus having a regulating member

Cleaning effectiveness is improved, and inadequate charging of the photosensitive member due to soiling of the charging brush as well as image noise such as background fog are suppressed by a developing device capable of recovering residual toner regardless of the toner charge polarity. In an image forming apparatus provided with a developing device including a developing sleeve for developing an electrostatic latent image on photosensitive member via toner and recovering residual toner from the surface of photosensitive member, a power unit is provided for forming a direct current electric field between photosensitive member and developing sleeve during developing, and forming alternating current electric fields between photosensitive member and developing sleeve 16 during cleaning of residual toners.

Image forming apparatus with developing recovery device

Developer material remaining on an image bearing member after transfer are collected by a developer. A cleaning member is arranged between a charger and an exposure in contact with the image bearing member, for collecting the residual developer material. A bias controller controls biases to be applied to a cleaner, a charger, and a developer. During an image forming process, the biases are so determined that the residual toner on the image bearing member is collected by the cleaner. While the image forming process is not performed, the biases are so determined that the collected toner is removed from the cleaner to the image bearing member and then collected by the developer.

Image forming apparatus

An image forming apparatus which is provided with a developing device having a rotatable developing member opposite to a rotatable photoreceptor at a developing region for transporting a developer to bring the developer into contact with the photoreceptor at the developing region, and a paper particle removing member provided at a downstream side from the developing region with respect to a rotational direction of the developing member for removing paper particles from the developer held on the developing member.

Developing device in an image forming apparatus for removing particulate

An one-component developing device includes an electrically conductive member which is located in a region extending from a position downstream, with respect to a moving direction of a surface of a toner carrying member, to a developing region, and is in contact with the surface of the toner carrying member. A surface of the electrically conductive member contacting the developing sleeve is formed of material, of which charge polarity is shifted to the same polarity side as a regular charge polarity of the toner in view of charge series, and which contains highly conductive material dispersed therein.

One-component developing device with system for removing surplus toner

An electrostatic latent image developing device includes a rotatable developing sleeve for providing an electrostatic latent image formed on a photoreceptor with a toner so as to develop the latent image into a visual image, and a toner regulating blade which contacts at one surface with the developing sleeve so that the toner is regulated and then formed into a thin layer. The toner regulating blade has, in a surface confronting the toner bearing member, a bevelled portion which forms a wedge shaped space in a upstream side of a contact region of the blade and the developing sleeve with respect to a direction of a movement of the developing sleeve. Further, the toner regulating blade has chamfered portions in the bevelled portion at both sides thereof. Therefore, the sleeve bears a toner thin layer having a constant density.

Toner regulating blade having a bevelled edge

A cleaning method for a contact type charger in an cleanerless image forming apparatus. The method includes a step of switching bias voltages applied to the contact type charger and a develop/cleaning device from first level to a second level so as to release developer adhering to the contact type charger onto an image-bearing member as well as to collect a part of the developer moved onto the image-bearing member by the developing/cleaning device, and a step of switching the bias voltage from the second level to the first level so as to collect the rest of the developer released onto the image-bearing member by the develop/cleaning device.

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Toyokawa, Japan

Akihiro Kawasaki