Ricoh Company, Ltd.

Daisuke Hamada

Hideo Yoshizawa

Seiichi Kogure

Atsushi Nakamoto

Jun Shiori

Takuya Akiyama

Shingo Kuboki

Yuuki Aoki

Yutaka Goto

Takahiro Adachi

Takeroh Kurenuma

Makoto Kawaguchi

Natsumi Matsue

Yutaka Takahashi

Akira Fujimori

An image forming apparatus includes a rotatable image bearer, a transfer rotator, a detector, and circuitry. The image bearer bears an image. The transfer rotator transfers the image from the image bearer onto a recording medium sandwiched and conveyed between the image bearer and the transfer rotator. The detector detects length information indicating a length, in a direction of conveyance of the recording medium, of the image on the recording medium. The circuitry corrects a correction value, based on the length information detected by the detector and a target value of the length information, to correct an image magnification, in the direction of conveyance of the recording medium, of the image to be formed on the recording medium. The circuitry controls an image forming operation of forming the image on the recording medium with the correction value.

Image forming apparatus

An image forming apparatus includes an image bearer, a transfer rotator, an adjuster, and circuitry. The image bearer bears a toner image. The transfer rotator contacts the image bearer to form a transfer nip between the transfer rotator and the image bearer. The transfer rotator transfers the toner image from the image bearer onto a sheet conveyed to the transfer nip. The adjuster adjusts at least one of a relative difference in linear velocity of the transfer rotator to the image bearer at the transfer nip and a relative contact pressure of the transfer rotator to the image bearer at the transfer nip. Based on a difference in image magnification, in a direction of conveyance of the sheet, of toner images transferred onto surfaces of one or more sheets conveyed to the transfer nip, the circuitry causes the adjuster to reduce the difference in image magnification.

Image forming apparatus and adjusting method

A roller unit includes a roller, an arm, a holder, a tension spring, and a restriction member. The arm rotatably holds the roller. The holder swingably holds the arm. The tension spring includes a first hook at one end of the tension spring and a second hook at another end of the tension spring. The first hook is hooked on an arm-side hook of the arm. The second hook is hooked on a holder-side hook of the holder. The restriction member is configured to restrict movement of the tension spring in a state in which the first hook or the second hook is unhooked.

Roller unit, belt device and image forming apparatus

A belt running device includes a plurality of rollers, a belt, a guide, a regulating member, and an abutting member. The belt is wound around the plurality of rollers and configured to rotate. The guide is provided at an end of an inner peripheral surface of the belt. The regulating member is provided at an end of at least one roller of the plurality of rollers in the axial direction of the at least one roller and configured to contact the guide and regulate a movement of the belt in the axial direction of the at least one roller. The abutting member is configured to contact an outer peripheral surface of the belt to press the belt inward in a vicinity of a contact start point at which the guide and the regulating member start to contact when the belt runs.

Belt running device, transfer device, and image forming apparatus

A developing device includes a developer container to contain developer including toner and magnetic carrier, the developer container; a developer bearer to carry, by rotation, the developer to a developing range facing a latent image bearer; a communication opening in a wall defining the developer container; a toner conveyance passage connected to the communication opening; and a cylindrical magnet having a magnetic pole arrangement parallel to an axis of the cylindrical magnet. The cylindrical magnet is disposed to enclose a space overlapping with the communication opening on a cross section perpendicular to the axis of the cylindrical magnet.

Developing device, and image forming apparatus and process cartridge incorporating same

A powder container for an image forming apparatus includes: a rotatable powder storage storing powder; an opening on one end of the powder storage, through which a nozzle can be inserted; and a scooping portion to scoop up powder on an opening side, and supply the powder to a powder receiving hole of the nozzle when the powder storage rotates. The scooping portion includes a scooping surface extending inwardly from an inner wall surface of the powder storage and an inner end portion extending in a rotation axis direction of the powder storage, with an edge approximately parallel to the rotation axis. In a cross-section perpendicular to the rotation axis, the scooping surface is inclined toward an upstream side in a rotation direction of the powder storage with respect to a virtual line that passes through the rotation axis and is tangent to the edge of the inner end portion.

Powder container and image forming apparatus

An image forming apparatus includes a latent image bearer having a shaft to rotate in a normal direction for image formation and a reverse direction, a charging device, a latent image forming device, a developing device including a developer bearer having a shaft, a driving source, a drive transmission device to transmit a driving force from the driving source to the shaft of the latent image bearer and the shaft of the developer bearer. The developer bearer rotates in a predetermined direction during image formation and transports developer including toner to a developing range facing the latent image bearer, thereby developing the latent image on the latent image bearer. The drive transmission device is configured to inhibit transmission of the driving force to the shaft of the developer bearer when the latent image bearer rotates in the reverse direction.

A developing device includes a casing having an opening, the casing to contain developer, and a developer bearer including a magnetized range to cause developer to stand on end on a surface of the developer bearer and an end range outside the magnetized range in a longitudinal direction of the developer bearer. The developer bearer is disposed in the casing and partly exposed from the opening with a casing gap secured between the surface of the developer bearer and an inner face of the casing. The developer bearer generates, by rotation, sucked-in airflow to collect a floating toner from the opening into the casing, and the casing gap is smaller in the end range than the magnetized range.

Developing device, process cartridge, and image forming apparatus incorporating same

A process cartridge is detachably mounted on an apparatus main body of an image forming apparatus. An embodiment of the cartridge includes a developer bearer arranged to be opposed to an image bearer in a developing device and rotates; a positioning member that supports the image bearer and the developer bearer at respective ends thereof, and fixes a distance between rotating shafts of the image bearer and the developer bearer; a rotating shaft arranged on a rotating member arranged on the developing device, and having a part protruding from an outer surface of a housing frame of the process cartridge; a gear that is arranged at a distal end of the rotating shaft and transmits a rotational driving force transmitted from the apparatus main body; and a bearing that is arranged between the positioning member and the gear, is fixed to the housing frame, and supports the rotating shaft.

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Kanagawa, Japan

Daisuke Hamada