Ricoh Company, Ltd.

Masami Okamoto

Kazuhito Kishi

Hiromasa Takagi

Yasutada Tsukioka

Akiyasu Amita

Yasuhisa Kato

Keisuke Kubota

Susumu Matsusaka

Kenji Nozawa

Shuutaroh Yuasa

Fumihiro Hirose

Kensuke Yamaji

Kaori Hemmi

Yuuki Kikushima

Ryuichi Kikegawa

Yuuta Kanda

Hiroyuki Shimada

Jun Okamoto

Naoto Suzuki

Seiji Saitoh

Yoshihiro Sonohara

Takashi Kagami

Kazuo Suno

Syoichi Kaneko

Yoshikuni Sasaki

Jun Ogino

Daisuke Inoue

Masahiko Satoh

Naoki Sato

Takahiro Honda

Kenta Kashiwagi

Yoshihisa Hara

An image forming apparatus including a developing device and a fixing device is provided. The fixing device includes a fixing rotator having a fixing surface, an opposing rotator opposing the fixing rotator to form a nip portion therebetween, and a fixing surface reformer having an abutting layer to abut the fixing surface. The abutting layer contains abrasive grains having an average grain size of 2.0-6.5 &#x3bc;m on a surface which abuts the fixing surface. The toner comprises a crystalline polyester resin and exhibits G' (storage elastic modulus) of 1.0&#xd7;10Pa or lower at 70&#xb0; C. in a temperature rising in a viscoelasticity measurement, G&#x2032; of 1.0&#xd7;10Pa or higher at 70&#xb0; C. in a temperature falling in the viscoelasticity measurement, and an endothermic peak indicating an amount of heat absorption of from 2.0 to 8.0 J/g, derived from the crystalline polyester resin, in a first temperature rising in DSC.

Image forming apparatus and image forming method

A separation member that is used to separate a conveyance object from two rotation members, the conveyance object having been sent out from a nip that is formed by the two rotation members that are in contact with one another, the separation member includes a wavy part directed toward the nip and inclined from a normal to a center line of the two rotation members at a predetermined angle. The wavy part covers a contact zone where the conveyance object can come into contact with the separation member along a conveyance direction and along a width direction of the conveyance object, and the wavy part has a plurality of depressions parallel to each other and extending in a direction inclined from the conveyance direction and inclined from the width direction, at least two of the depressions overlapping along the conveyance direction.

Separation member, separation device, fixing device, and image forming apparatus

A fixing device includes a tubular rotator and a first heater disposed inside the tubular rotator and extended in a longitudinal direction of the first heater. The first heater heats the tubular rotator. A second heater is disposed inside the tubular rotator and extended in a longitudinal direction of the second heater. The second heater heats the tubular rotator. A heating adjuster is interposed between the first heater and the second heater. The heating adjuster adjusts heat conduction from the first heater to the second heater. A joint combines the heating adjuster with the second heater.

Fixing device and image forming apparatus

A fixing device includes a separator disposed downstream from a nip former in a recording medium conveyance direction and isolated from a pressure rotator via a fixing belt. The separator stretches the fixing belt. A presser is interposed between a fixing nip formed between the living belt and the pressure rotator and an upstream end of the separator in a rotation direction of the fixing belt. The presser comes into contact with an inner circumferential surface of the fixing belt to press the fixing belt against the pressure rotator. A pressure adjuster, contacting the pressure rotator, changes a pressing position of the pressure rotator relative to the fixing belt to adjust pressure exerted from the pressure rotator to the fixing belt. A presser position adjuster, contacting the presser, changes a presser position of the presser relative to the fixing belt according to the pressing position of the pressure rotator.

A fixing device includes a fixing belt that is endless and rotatable in a rotation direction and a nip former stretching the fixing belt. A pressure rotator presses against the nip former via the fixing belt to form a fixing nip between the fixing belt and the pressure rotator, through which a recording medium is conveyed. A separator is disposed downstream from the nip former in a recording medium conveyance direction and stretches the fixing belt. The separator is spaced apart from the pressure rotator via the fixing belt. A presser is interposed between an exit of the fixing nip and an upstream end of the separator in the rotation direction of the fixing belt. The presser comes into contact with an inner circumferential surface of the fixing belt to press the fixing belt against the pressure rotator.

A fixing device includes a fixing belt that is endless and rotatable in a rotation direction and a nip former stretching the fixing belt and including an elastic layer as a surface layer. A pressure rotator presses against the nip former via the fixing belt to form a fixing nip between the fixing belt and the pressure rotator, through which a recording medium is conveyed. A presser is disposed downstream from an exit of the fixing nip in a recording medium conveyance direction. The presser brings the fixing belt into contact with the pressure rotator.

A fixing device includes a fixing belt that is endless and rotatable in a rotation direction and a nip former stretching the fixing belt. A pressure rotator presses against the nip former via the fixing belt to form a fixing nip between the fixing belt and the pressure rotator, through which a recording medium is conveyed. A presser is disposed downstream from an exit of the fixing nip in a recording medium conveyance direction. The presser brings the fixing belt into contact with the pressure rotator. A gap retainer contacts the nip former and is coupled to the presser to retain isolation of the presser from the nip former.

Fixing device and image forming apparatus including a fixing belt, a presser, and a gap retainer

A fixing device includes a fixing belt that is endless and rotatable in a rotation direction and a nip former stretching the fixing belt. A pressure rotator presses against the nip former via the fixing belt to form a fixing nip between the fixing belt and the pressure rotator, through which a recording medium is conveyed. A presser is disposed downstream from an exit of the fixing nip in the rotation direction of the fixing belt. The presser brings the fixing belt into contact with the pressure rotator. A mover is coupled to the presser to move the presser between a contact position where the presser brings the fixing belt into contact with the pressure rotator and an isolation position where the presser isolates the fixing belt from the pressure rotator.

Fixing device and image forming apparatus with a movable presser which moves a fixing belt

A fixing device includes an endless fixing belt stretched taut across a first roller and a second roller and rotatable in a predetermined direction of rotation. A pressure rotator is pressed against the first roller via the fixing belt to form a fixing nip between the pressure rotator and the fixing belt, through which a recording medium is conveyed. A separation aid, disposed downstream from the fixing nip in the direction of rotation of the fixing belt to separate the recording medium from the fixing belt, includes a contact face contacting an inner circumferential surface of the fixing belt and a bulge disposed at a center of the contact face in a longitudinal direction of the separation aid. The bulge projects toward the inner circumferential surface of the fixing belt relative to each lateral end of the contact face in the longitudinal direction of the separation aid.

Fixing device and image forming apparatus that include a separation aid disposed downstream from the fixing nip

A fixing device includes a fixing belt looped over a first roller and a second roller and rotatable in a predetermined direction of rotation and a pressure rotator to press against the first roller via the fixing belt to form a fixing nip between the fixing belt and the pressure rotator. A separation aid, disposed downstream from the fixing nip in the direction of rotation of the fixing belt, contacts an inner circumferential surface of the fixing belt to decrease a radius of curvature of the fixing belt. A polishing roller, disposed downstream from the separation aid and upstream from the second roller in the direction of rotation of the fixing belt, contacts an outer circumferential surface of the fixing belt. An opposed roller, disposed opposite the polishing roller via the fixing belt, forms a polishing nip between the polishing roller and the fixing belt.

A fixing device includes a cylindrical heat roller; a plurality of heaters disposed inside the heat roller, extending along a longitudinal axis of the heat roller; and a heat adjuster, disposed among the plurality of heaters, to adjust heat from one to another of the plurality of heaters. An image forming apparatus includes an image forming section to form an image on a recording medium; and the fixing device as described above, to fix the image onto the recording medium.

A fixing device includes a guide disposed downstream from a fixing nip formed between a fixing rotator and a pressure rotator, through which a recording medium is conveyed. A pressure rotator side separator, disposed downstream from the fixing nip in a recording medium conveyance direction, includes an opposed tip disposed opposite an outer circumferential surface of the pressure rotator and a separation-conveyance face that separates the recording medium from the pressure rotator. The opposed tip and the separation-conveyance face define a hypothetical circle having a curvature not smaller than 1/20 that intersects a guide face of the guide at an intersection at which a hypothetical tangent is tangent to the hypothetical circle. The hypothetical tangent and the guide face define a downstream intersection angle that is downstream from the hypothetical tangent in the recording medium conveyance direction and is greater than 90 degrees.

Fixing device including a separator to separate a recording medium from a pressure rotator and image forming apparatus including the fixing device

A fixing device includes a first roller contacting a fixing belt to generate a rotation friction force therebetween to rotate the fixing belt and a second roller contacting the fixing belt to exert a first inhibition force to the fixing belt in a direction opposite a direction of rotation of the fixing belt. A separation aid is disposed downstream from a fixing nip formed between the fixing belt and a pressure rotator in the direction of rotation of the fixing belt to decrease a curvature of the fixing belt and exert a second inhibition force to the fixing belt in the direction opposite the direction of rotation of the fixing belt. The second inhibition force is added to the first inhibition force to obtain a combined inhibition force that is smaller than the rotation friction force between the fixing belt and the first roller.

A fixing device includes a fixing belt stretched taut across a fixing rotator and a support rotator. A pressure rotator is pressed against the fixing rotator via the fixing belt to form a fixing nip between the fixing belt and the pressure rotator, through which a recording medium bearing a toner image is conveyed. The pressure rotator includes a recess defining an outer diameter of each lateral end of the pressure rotator in an axial direction thereof that is greater than an outer diameter of a center of the pressure rotator in the axial direction thereof. A first separator is disposed downstream from the fixing nip in a recording medium conveyance direction and contacts an inner circumferential surface of the fixing belt. The first separator is isolated from the pressure rotator and includes a projection disposed opposite the recess of the pressure rotator.

Fixing device and image forming apparatus that include a separator disposed downstream from a fixing nip

A fixing device includes an elastic rotator and a cooler disposed opposite the rotator to cool the rotator with cooling air. A mover contacts and moves the rotator to a first position where the rotator is disposed opposite the cooler with an increased first interval therebetween and a second position where the rotator is disposed opposite the cooler with a decreased second interval therebetween. A rectification plate is movably mounted on the cooler to contact the rotator constantly to guide the cooling air to the cooler.

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Kanagawa, Japan

Masami Okamoto