Ricoh Company, Ltd.

Toshitaka Yamaguchi

Masaru Tanaka

Ken Amemiya

Haruji Mizuishi

Takeo Suda

Masaharu Furuya

Kenzo Tatsumi

Takuya Sekine

Hiroshi Yoshinaga

Shigeru Watanabe

Junpei Fujita

Kazuchika Saeki

Takahiro Nakayama

Mayumi Ohori

Kenzou Tatsumi

Shinya Tanaka

Kenji Sugiura

Hirokazu Ishii

Naohiro Kumagai

Seiichi Kogure

Kazuki Yogosawa

Yuuji Wada

Hideki Zemba

Hiroyoshi Haga

Hiroshi Mizusawa

Tatsuya Ohsugi

Mitsuru Sato

Akio Kutsuwada

Noriyuki Usui

Makoto Arai

Masayoshi Nakayama

Jyunya Sakuraba

Mayumi Oh-Hori

Takeshi Saito

Hiroshi Ono

Masato Yanagida

Takehide Mizutani

Yasushi Koichi

Mayumi Yoshida

Katsuhito Haruno

Yoshiyuki Tanimoto

Ryoh Tanoue

Masaki Tokuhashi

An image forming apparatus includes an image bearer, a transfer member, and a power source. The image bearer includes a plurality of layers. The transfer member forms a transfer nip between the image bearer and the transfer member. The power source outputs a transfer bias to transfer a toner image from the image bearer onto a recording sheet in the transfer nip. The transfer bias alternates between a transfer-side bias that causes the toner image to move from the image bearer to the recording sheet, and an opposite-side bias different from the transfer-side bias. A duty ratio of a time period, during which the opposite-side bias is output, relative to one cycle of a waveform, is greater than 50%.

Image forming apparatus

An image forming apparatus includes an image bearer, a toner image forming device, a nip forming device, a power source, a controller, and a temperature-and-humidity detector. The toner image forming device forms a toner image on the image bearer. The nip forming device contacts the image bearer to form a transfer nip. The power source outputs a transfer bias, in which an alternating current component is superimposed on a direct current component, to transfer the toner image onto a recording medium interposed in the transfer nip. The temperature-and-humidity detector detects a temperature and humidity. The controller controls the power source to output the transfer bias including the direct current component with a smaller absolute value as at least one of the detected temperature and humidity increases.

Image forming apparatus controlling transfer bias based on temperature and humidity

An image forming apparatus includes a toner image carrying member, an image transfer device, a fixing device, a registration unit, a guide member, an upstream-side transportation unit, and a downstream-side transportation unit. The image transfer device transfers a toner image from the toner image carrying member to a recording medium. The fixing device fixes the toner image. The registration unit transports the recording medium. The guide member guides the recording medium. The upstream-side transportation unit includes an upstream-side transportation member, disposed at an upstream side in the transport direction of the recording medium. The downstream-side transportation unit includes the downstream-side transportation member, disposed at a downstream side in the transport direction of the recording medium. The upstream-side transportation unit includes an upstream-side positioning member to position the guide member to the upstream-side transportation member. The downstream-side transportation unit includes a downstream-side positioning member to position the guide member to the downstream-side transportation member.

An image forming apparatus includes an intermediate transfer belt, a photosensitive belt, a primary transfer roller, a secondary-transfer opposing roller, and a secondary transfer roller. The photosensitive belt comes into contact with a surface of the intermediate transfer belt to form a primary transfer nip. The secondary-transfer opposing roller comes into contact with the surface of the intermediate transfer belt to form a secondary transfer nip. The closest distance between a surface of the photosensitive belt and that of the primary transfer roller is greater than the thickness of the intermediate transfer belt. A toner image on the intermediate transfer belt is transferred onto a recording sheet at the secondary transfer nip while a transfer bias is applied to the secondary transfer roller.

Transfer device and image forming apparatus having first and second transfer nips and first and second contacting members which apply transfer biases

A transfer device, which transfers an image onto a recording medium directly or indirectly and is included in an image forming apparatus, includes an endless belt member extended between a drive roller rotated and a driven roller and configured to receive the image from the image carrier part onto either a surface thereof or the recording medium carried on the surface thereof while moving according to rotations of the drive roller, and a rotation speed detector configured to detect a rotation speed of the driven roller. An image detector is provided either to the transfer device or to the image forming apparatus to detect the image formed on the endless belt member directly or the recording medium carried on the endless belt member, and disposed facing the driven roller in a circumferential direction of the endless belt member.

Transfer device and image forming apparatus including same

Transfer device and image forming apparatus having at least two contacting members applied with corresponding transfer biases

A belt member faces a plurality of carrying bodies that respectively carry toner images or developers. A plurality of facing members respectively faces the carrying bodies via the belt member. A detaching unit brings at least one of the facing members to face a corresponding carrying body and detaches other facing members from other carrying bodies. A contacting member contacts the belt member to detach the belt member from the other carrying bodies when the detaching unit detaches the other facing members from the other carrying bodies.

Belt detaching device and image forming apparatus including belt detaching device

An optical sensor detects at least one of a toner image and a toner adhesion amount per unit area based on a change of an optical characteristic on a surface of an endless belt member. A control unit performs a predetermined process based on a detection result obtained by the optical sensor. A sensor moving unit moves the optical sensor between a first position in opposite to a belt supporting area in which the endless belt member is supported by a supporting roller and a second position that is different from the first position. The detection result is obtained by the optical sensor when the optical sensor is placed at the first position by the sensor moving unit.

Compact image forming apparatus with a moveable optical sensor

An image-forming apparatus includes an image-bearing device that holds an electrostatic latent image and a toner image thereon, and a developer container that contains and agitates a developer having at least a toner. The image-forming apparatus also includes a developer-bearing device that carries the developer to develop the electrostatic latent image on the image-bearing device, and a density sensor that detects an optical density of a surface of the image-bearing device and a toner image on the image-bearing device. Further, the image-forming apparatus includes a developer seal that seals the developer in the developer container, wherein the seal is disposed between the developer container and the developer-bearing device, and an actuator configured to actuate the developer container and the developer-bearing device. The image-forming apparatus still further includes a control device that determines whether the developer seal is removed according to information on the optical density of the toner image output by the density sensor.

Image-forming apparatus having a seal for a developer and a method for detecting a removal of the seal

An image forming apparatus includes an image carrier and a developing device to develop a latent image formed on the image carrier by applying two-component developer, including toner, onto the latent image. The developing device includes a developing part containing the two-component developer and a developer stirring device to stir the two-component developer. A toner supplying device supplies toner to the developing part of the developing device, and a toner density detection device detects a toner density of the two-component developer in the developing device. A toner control device calculates a difference between an output value VT of the toner density detection device and a criterion value VTref for controlling the toner density of the two-component developer and controls the toner supplying device based upon the difference. An image density detection device detects an image density of a criterion image formed on the image carrier, and a criterion value correcting device corrects the criterion value VTref based upon an output value of the criterion image density detection device. A decision as to whether to stir the developer in the developing device with the developer stirring device is made based upon a difference between the criterion value VTref and the output value VT from the toner density detection device and an output value of the criterion image density detection device when an image forming operation is started.

Image forming apparatus with improved toner density control

An image forming apparatus is provided, which includes an image bearing member, a transfer roller having a shaft for transferring an image on the image bearing member to a transfer sheet, a bearing mechanism for supporting the shaft, a discharging device for discharging the transfer, and a joint mechanism which mechanically connects the discharging device with the transfer roller at both ends of the shaft. Both of the transfer roller and the discharging device can be integrally detached from and attached to the image forming apparatus without detaching/attaching the bearing mechanism, by use of a handle. Therefore, an operation for replacing the transfer roller and the discharging device can be performed easily.

Image forming apparatus having detachable transfer roller and discharge

An image forming apparatus includes an image bearing member, a latent image forming device that forms a latent image on the image bearing member, a developing device that develops latent image on said image bearing member to a toner image with a two-component developer, and a toner density detecting device that detects toner density of the two-component developer in which the toner image is formed and outputted as a visible image onto a transfer member. A control device is provided for agitating the developer for a predetermined time period during an initial setting is performed for the developer, detecting a toner density of said developer after the predetermined agitation, and performing an abnormal process when a result of the detection is out of the predetermined range. A corresponding method recovers from a deterioration of an amount of charge of the toner and decreased bulk of the developer, and includes the steps of detecting a developer amount with an unused-state detection switch, detecting an output value of a toner density detecting sensor, agitating the developer, measuring an agitating time period, stopping the agitating operation indicating warning, and indicating error message.

Image forming apparatus and method for obtaining appropriate toner

An image forming apparatus including an image bearing member, a latent image forming device which forms a latent image on the image bearing member, a developing device which develops the latent image using a two-component developer including a toner and a carrier and a toner supplying device which supplies toner into the developing device. A developer agitating device agitates developer in the developing device and a toner-density detecting device detects a toner density of developer in the developing device. A toner-density control device controls the toner density by operating the toner supplying device on the basis of a detected result according to the toner-density detecting device. A memory device stores resultant value of the toner density detected by the toner-density detecting device during image forming operations. The toner-density detecting device detects the toner density in a warm-up operation before starting the image forming operation by the image forming apparatus. The toner-density control device changes an amount of the toner supply which is supplied by the toner supplying device after starting the image forming operation according to a result of a comparison of the detected toner density in the warm-up operation with the detected result stored in the memory device. The toner-density control device changes an amount of the toner supply which is supplied by the toner supplying device after starting the image forming operation according to the resultant value of comparison of a result of a detection.

Image forming method and apparatus for controlling amount of supplied

An image forming apparatus which transfers a toner image formed on an image carrier to a recording medium with a transfer device and separates the recording medium from the image carrier by discharging the recording medium with a discharging device. The image forming apparatus includes a support member which supports the transfer device and which includes a first support element pivotally mounted to a main body of the apparatus and a second support element. The second support element is pivotally mounted to the first support element at one end and unattached at the other end. The second support element may be solely supported by the first support element. The first support element is supported from below and by pivoting a support member out from under the first support element, the transfer device moves between a working position facing a surface of the image carrier and a recessed position separated from the image carrier by a larger distance than when the transfer device is in the working position. A relatively large space is thus formed between the image carrier and the transfer device and clearance of a jammed sheet is facilitated. The transfer device is detachable from the second support element and the discharging device is also detachable from the second support element independently or integrally with the transfer device.

Image forming apparatus with a folding transfer device support member

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Ohmiya, Japan

Toshitaka Yamaguchi