Ricoh Company, Ltd.

Cti Engineering Co. Ltd.

Ken Yoshida

Daisuke Ito

Hiromi Ogiyama

Shinji Kato

Shin Kayahara

Yoshihiro Fujiwara

Yuuji Sawai

Atsushi Takehara

Daisuke Takahashi

Keiko Matsumoto

Yoichi Sakurai

Shinji Aoki

Yasunobu Shimizu

Akio Kosuge

Jun Yura

Tetsuya Muto

Tomohide Takenaka

Naoyuki Ozaki

Emiko Ishikawa

Masako Yoshii

Masahiro Katoh

Ichiro Maeda

Jiaxing Ye

An image forming apparatus includes at least one image bearer; multiple developing devices to develop the latent images with developers including toner and carrier into a toner image; multiple developer supply devices to supply the developers to the multiple developing devices, respectively; and a fixing device to fix the toner image on a sheet of recording media. When one of the multiple developing devices positioned at a shortest distance from an outline of the fixing device is referred to as a first developing device, and one of the multiple developer supply devices that supplies developer to the first developing device is referred to as a first developer supply device, the first developer supply device is greater in percentage by weight of carrier in developer supplied to the first developing device than rest of the multiple developer supply devices.

Image forming apparatus

An image forming apparatus includes an image carrier, a transfer unit, and a control unit. The image carrier has a surface to bear a toner image thereon. The transfer unit has a transfer member to transfer the toner image onto a recording sheet conveyed in a conveyance direction for trailing-end borderless image formation and duplex image formation. The transfer unit is configured to form the toner image on the recording sheet without forming a margin at a trailing end of the recording sheet in the conveyance sheet in the trailing-end borderless image formation. The transfer unit is configured to form the toner image on front and back faces of the recording sheet in the duplex image formation. When a width of the toner image formed in a borderless image area of the recording sheet in the trailing-end borderless image formation is smaller in a direction perpendicular to the conveyance direction than a threshold value, the control unit permits the duplex image formation. When the width is the threshold value or greater, the control unit prohibits the duplex image formation.

An image forming apparatus includes: an image carrier; a transfer member arranged so as to face the image carrier; and a non-transferred toner adhesion unit that causes a non-transferred toner to adhere to an inter-sheet area present on the image carrier during a period of continuous image formation in which images are continuously formed on the image carrier. The transfer member is a foam roller. The image forming apparatus further includes a contacting and separating unit that causes the foam roller and the image carrier to come into contact with and be separated from each other. The contacting and separating unit separates the image carrier and the transfer member when the inter-sheet area present on the image carrier passes through a transfer area in which the image carrier and the transfer member face each other in association with rotation of the image carrier.

Image forming apparatus that suppresses deterioration in image quality

An image forming apparatus includes a transfer device separator that moves a transfer device between a contact position and a first isolation position within a shortened time. At the contact position, the transfer device contacts a toner image carrier. At the first isolation position, the transfer device is isolated from the toner image carrier with a first interval therebetween. A controller controls the transfer device separator to move the transfer device to the contact position as first to third toner images and a blank section between the first toner image and the second toner image carried by the toner image carrier pass through a transfer region and to the first isolation position as a toner patch section between the first toner image and the second toner image carried by the toner image carrier passes through the transfer region.

Image forming apparatus with mechanism capable of moving transfer device with respect to toner image carrier and image forming method for moving transfer device with respect to toner image carrier

An image forming apparatus for transferring and superimposing toner images formed on plural image bearers onto an endless intermediate transfer member in an electric field created between the plural image bearers and plural semi conductive transfer members internally contacting the endless intermediate transfer member. The image forming apparatus includes a heat generating member arranged inside the intermediate transfer member to generate heat. A heat transfer member is provided to transfer the heat to the plural semi conductive transfer members.

Image forming apparatus including heat transmission member

An image forming apparatus includes an image bearing member to bear a toner image, a transfer device to transfer the toner image onto a recording medium, and a moving device controller to control a moving device that moves the transfer device such that the moving device moves the transfer device to contact the image bearing member during transfer of the toner image on the image bearing member to the recording medium; separates the transfer device from the image bearing member as a toner patch on the image bearing member passes through the transfer area; and maintains the transfer device in contact with the image bearing member from a preceding transfer of a toner image to a succeeding transfer of a toner image during continuous printing, as at least one of areas between successive toner images on the image bearing member without the toner patch passes through the transfer area.

An image forming apparatus includes an image carrier, a transferer to apply a constant-current controlled bias to a transfer medium to form a transfer electric field, a constant-current source configured to apply an electrical current to the transferer, an electrical characteristic detector, an environment detector, a first corrector, a second corrector, and a third corrector. The electrical characteristic detector detects an electrical characteristic value corresponding to a resistance in a current path from the constant-current source to the transferer. The environment detector detects an environmental condition inside the image forming apparatus. The first corrector corrects the electrical current based on the electrical characteristic detection and a predetermined threshold. The second corrector corrects the electrical current based on the environment detection. The third corrector sets the threshold based on the environment detection.

Image forming apparatus and methods of setting transfer current and forming image

An image forming apparatus includes a first image carrier forming a black toner image, a plurality of second image carriers forming a yellow, magenta, or cyan toner image, a third image carrier forming a special color toner image, and a transfer target member or an intermediate transfer belt. The apparatus further includes first and second detachment units. The first detachment unit detaches only the third image carrier from the transfer target member, and the second detachment unit detaches the second image carriers and the third image carrier. When switching from a special color image mode to either a normal color image mode or a monochrome image mode is performed during continuous printing of the recording media, the first detachment unit or the second detachment unit controls the detachment operation based on the number of recording media continuously printed by the normal color image mode or the monochrome image mode.

Image forming apparatus having a special color image mode

An image forming apparatus for forming a visual image on a recording medium includes a toner replacing device that replaces toner stored in a developing device with fresh toner, and a determiner that determines if a recording medium selected by a user necessitates replacement of the toner. The toner replacing device replaces the toner with fresh toner when the determiner determines that the recording medium necessitates replacement of the toner before the latent image is formed on a photoconductive member.

Image forming apparatus capable of forming high quality toner image on uneven surface sheet

An image forming apparatus including multiple colored toner image forming units to form multiple colored toner images on a rotatable body, a transfer device to collectively transfer the multiple colored toner images onto a recording medium from the rotatable body, a fixing device to fix the multiple colored toner images onto the recording medium, and a light-colored toner image forming unit to form a light-colored toner image as a bottommost layer of a resultant full-color toner image formed on the rotatable body. The multiple colored toner images are sequentially superimposed on the light-colored toner image formed as the bottommost layer of the resultant full-color toner image formed on the rotatable body. A condition for forming the light-colored toner image by the light-colored toner image forming unit is set such that the light-colored toner image is not transferred onto the recording medium from the rotatable body by the transfer device.

Image forming apparatus for improving transfer efficiency and preventing image deterioration

Image forming apparatus including pressers configured to press a receptor to image bearers downward in the vertical direction

Heat transmission member included image forming apparatus

An image forming apparatus including a latent image carrier, a charger to evenly charge a surface of the latent image carrier, a writing device to irradiate a charged surface of the latent image carrier to form an electrostatic latent image, a writing device control unit to control the writing device, a developing device to develop the electrostatic latent image to form a toner image, a transfer device to transfer the toner image onto a transferred member, and a pre-transfer irradiating device to irradiate the charged surface of the latent image carrier during a period after development and before transfer. The writing device control unit controls the writing device based on a target image signal A and an image signal B output a single rotation of the latent image carrier after output of the target image signal A in a sub-scanning direction.

Image forming apparatus utilizing plural pressers of different weights and image forming method forming an image with the image forming apparatus

An image forming apparatus includes a plurality of image forming units and a plurality of transfer units. The image forming units have corresponding image carriers and charging units. The image forming units form toner images of different colors on the corresponding image carriers. The transfer units face the corresponding image carriers to form transfer areas between the transfer units and the image carriers, and press a transfer member to the corresponding image carriers to transfer the toner images onto the transfer member at the transfer areas. The charging units include at least one corona-type charger and at least one contact-type charger. The image forming apparatus sets a first transfer condition for the transfer unit(s) corresponding to the image carrier(s) charged by the at least one corona-type charger and a second, separate transfer condition for the transfer unit(s) corresponding to the image carrier(s) charged by the at least one contact-type charger.

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Chigasaki, Japan

Ken Yoshida