Ricoh Company, Ltd.

Yuichi Aizawa

Tadashi Kasai

Makoto Yasuda

Kazuaki Kamihara

Masayoshi Nakayama

Masaki Sukesako

Takuma Higa

Hitoshi Yamamoto

Kohei Matsumoto

Mutsuki Morinaga

Emiko Shiraishi

Masakazu Terao

Masahiro Katoh

Masato Iio

Hiroyuki Kunii

Tomohide Takenaka

Masashi Tachi

Toshio Koike

Hiroaki Suzuki

Kiyonori Tsuda

Yutaka Takahashi

Toshihiro Sugiyama

Kazumi Kobayashi

Kunio Hasegawa

Takamasa Ozeki

Keinosuke Kondoh

Keita Sone

Yoichi Sakurai

Jun Hitosugi

Wakana Itoh

Kentaro Mikuniya

Takatsugu Komori

Masanori Kurosawa

Hiroyuki Kunil

An image forming apparatus includes a latent image bearer to bear a latent image, a potential sensor having a vibrator driven by a drive frequency to detect a surface potential of the latent image bearer, a developer bearer to bear developer that develops the latent image on the latent image bearer, and a power supply to apply a superimposed voltage obtained by superimposing an alternating voltage on a direct current voltage on the developer bearer. The frequency of the alternating voltage is not a multiple of the drive frequency and is a value obtained by adding a predetermined value to a multiple of the driving frequency.

Image forming apparatus and voltage application method

An electrophotographic image forming apparatus includes a latent image bearer to rotate and bear a latent image, a charging device to charge the a latent image bearer, a developing device to develop the latent image with developer including toner and use a developing voltage including an AC component, and a lubricant applicator to apply lubricant onto a surface of the latent image bearer. An amount of the lubricant applied by the lubricant applicator onto the latent image bearer per centimeter in an axial direction of the latent image bearer is equal to or greater than 0.845 mg for a running distance of 1.0 kilometer of the latent image bearer, and a difference between a largest value and a smallest value of the developing voltage is in a range of 200 V to 400 V.

Image forming apparatus

An image forming apparatus includes an image bearer, an image forming device, a toner concentration detector, a toner supply device, an image density detector, and a controller including a memory device. At a predetermined timing before image formation is started, the controller adjusts a developing potential to adjust an image density of a detection toner image on the image bearer and drives the toner supply device or the developing device to adjust a toner concentration in the developing device. After the image formation is started, the controller drives the toner supply device to adjust the toner concentration, and, in a predetermined sheet interval, adjusts the target concentration based on the image density of the detection toner image formed in a non-image area of the image bearer. When the toner concentration is higher than the target concentration plus a threshold, the controller suspends image formation and readjusts the developing potential.

Image forming apparatus comprising image density detector and toner concentration detector

An image forming apparatus includes a first electric charging unit having an electric discharge wire to uniformly electrify a surface of the electrostatic latent image bearer, a second electric charging unit having a second electric discharge wire to execute a pre-electric charge removal electric charging process by electrifying the surface of the electrostatic latent image bearer subsequent to a transfer process to transfer a toner image, and a first electric charge removing device to diselectrify the surface of the electrostatic latent image bearer by irradiating it with electric charge removing light subsequent to the pre-electric charge removal electric charging process. The first electric charge removing device is disposed within an electric discharge region of the second electric discharge wire on a downstream side of an extreme upstream edge of the electric discharge region of the second electric discharge wire in a rotational direction of the electrostatic latent image bearer.

Image forming apparatus including electric charge removing device and method of forming image

An image forming apparatus includes a latent image bearer; a developing device containing two-component developer and including a developer bearer, a development voltage source, and a toner concentration detector; a toner supply device to supply toner to the developing device; a transfer device; and a controller to keep a toner concentration in the developer in the developing device at a target toner concentration during image formation. The controller executes forced toner consumption in which the developing device supplies the toner to the latent image bearer the toner at a predetermined forced toner consumption timing, while inhibiting the toner supply device from supplying toner. When the toner concentration falls to a prescribed toner density lower than the target toner concentration, the controller completes the forced toner consumption and executes a post-consumption toner supply operation.

An image forming apparatus includes a plurality of image bearing members, replaceable development units, replaceable toner replenishing members, toner supply units, and a control unit. The development units are each provided for a corresponding one of the plurality of image bearing members. The toner replenishing members are each provided for a corresponding one of the development units. The toner supply units are arranged between the respective toner replenishing members and the development units. The control unit causes the image forming apparatus to execute a toner supply unit cleaning mode to convey a last-used toner inside the toner supply unit into the development unit which is last used and to be replaced to empty the toner supply unit, when replacement of the development unit and the corresponding toner replenishing member is designated to use a toner of a type different from the last-used toner.

Image forming apparatus and cleaning of image forming apparatus

An image forming apparatus includes a plurality of image forming stations, each including a developing device, a toner container containing a colored or special toner, and a replaceable supply-toner conduit extending from the toner container to the developing device; and a toner type identifier to identify a type of toner used in the supply-toner conduit of each of the plurality of image forming stations.

A developing device includes a developer bearer to carry, by rotation, developer including toner and magnetic carrier to a development range facing a latent image bearer, and the developer bearer includes a magnetic field generator having multiple magnetic poles and a cylindrical developing sleeve to rotate and bear developer on an outer circumferential face thereof with magnetic force of the magnetic field generator provided inside the developing sleeve. The developing sleeve receives developing bias voltage including an AC component, and includes a base to maintain a cylindrical shape of the developing sleeve and a low friction surface layer including a material lower in friction coefficient with toner than a material of the base.

Developing device and image forming apparatus and process cartridge incorporating same

An image forming apparatus includes a color toner image forming device, a fixing device, a cooling device, a colorless toner image forming device, and a control device. The color toner image forming device forms a toner image on a recording medium with a color toner. The fixing device heats the toner image on the recording medium to fix the toner image on the recording medium. The cooling device cools the fixed toner image. The colorless toner image forming device forms a toner image on the recording medium with a colorless toner having a storage elastic modulus of 100 or less and a loss tangent of 10 or greater at a heating temperature of the fixing device. The control device controls cooling power of the cooling device based on whether or not the colorless toner image forming device forms the toner image.

Image forming apparatus which includes a colorless toner image forming device

An inverse image data generating unit that generates inverse image data that indicates a transparent developer amount that indicates an amount of a transparent developer, and a region where the transparent developer amount is used, based on a color plane image data that indicates a color developer amount that indicates an amount of a color developer, and a region where the color developer amount is used; a conversion unit that converts the transparent developer amount of the inverse image data into a transparent developer amount larger than the transparent developer amount by referring to a conversion table; and a transparent developer plane image data generating unit that generates transparent developer plane image data used in image formation of a transparent developer in an image forming apparatus based on the inverse image data indicating a transparent developer amount after the conversion.

Print control device and print control method

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Kanagawa, Japan

Yuichi Aizawa