Ricoh Company, Ltd.

Akiko Ito

Tadashi Ogawa

Hiroshi Seo

Kenji Ishii

Satoshi Ueno

Toshiaki Higaya

An image forming apparatus includes an image carrier to carry a toner image and a fixing device to fix the toner image transferred from the image carrier onto a recording medium by applying at least heat to at least one of the toner image and the recording medium. Such a fixing device includes: a magnetic flux generator to generate a magnetic flux; and a heat generating member disposed at least partially in the magnetic flux. The heat generating member includes a heat generating layer to generate heat via eddy currents therein induced by the magnetic flux, magnitudes of the eddy currents varying according to positions thereof in a width direction of the heat generating layer. Included within the heat generating layer is a magnetic layer having a Curie point in a range, e.g., from about 100 degrees centigrade to about 300 degrees centigrade.

Image forming apparatus and fixing device

A fixing unit includes a rotatable fixing member and a rotatable pressure applying member. The rotatable fixing member has a heat generating layer to generate heat when subject to a magnetic flux. The rotatable pressure applying member contacts the rotatable fixing member and applies pressure to the fixing member. The rotatable fixing member and the rotatable pressure applying member form a nip therebetween, to which a recording medium is passed through to fix an image on the recording medium. The rotatable fixing member includes a magnetism regulating layer deformable when subject to pressure from the rotatable pressure applying member.

Fixing unit having enhanced temperature control and image forming apparatus using the same

A fixer configured to fix an image on an recording medium passing through a fixing nip includes a holder including an elastic layer, a fixing rotator including a heating layer, provided overlying the holder, and a pressurizer configured to pressurize the holder via the fixing rotator to form the fixing nip. A part of the pressurizer, which forms the fixing nip, has a length not less than a length of the heating layer in a width direction perpendicular to a conveyance direction of the recording medium.

Fixer and image forming apparatus including the same

A fixing device includes an excitation coil, a heat-generating layer, a magnetic shunt layer, and a degaussing member. The excitation coil generates a magnetic flux. The heat-generating layer generates heat using the magnetic flux generated by the excitation coil. The magnetic shunt layer transmits heat generated by the heat-generating layer. The degaussing member sandwiches the magnetic shunt layer together with the excitation coil, and selectively performs degaussing by generating a repelling magnetic flux for canceling the magnetic flux generated by the excitation coil so as to activate a self-temperature-control function. The degaussing member selectively refrains from degaussing so as to deactivate the self-temperature-control function.

Fixing device, image forming apparatus including the fixing device, and fixing method

An image forming apparatus includes a fixing device to fix a toner image on a recording medium by applying heat. Such a fixing device includes at least a magnetic flux generator, a heat generating roller, a magnetic shunt layer, and a protective layer. The magnetic flux generator is configured to generate magnetic flux. The heat generating roller including a heat generating layer is configured to generate heat by the magnetic flux. The magnetic shunt layer may be formed independently of the heat generating layer. The protective layer is provided on an inner surface of the magnetic shunt layer and configured to cover a crack formed in the magnetic shunt layer during fabrication of the magnetic shunt layer. An image is fixed onto the recording medium by the heat from the heat generating roller. Alternatively, the magnetic shunt layer may be integrally provided with the heat generating layer.

Fixing device using electromagnetic induction heating and image forming apparatus including same

A fixing device includes a magnetic flux generator, a rotating heat generation member, a magnetic flux adjuster, and a driver. The magnetic flux generator generates a magnetic flux. The rotating heat generation member rotates and applies heat to a recording medium bearing an image, and includes a heat-generating layer to generate heat using the magnetic flux generated by the magnetic flux generator. The magnetic flux adjuster is provided outside the rotating heat generation member, and decreases the magnetic flux applied to the heat-generating layer at least in a desired area in an axial direction of the rotating heat generation member. The driver changes the desired area by driving the magnetic flux adjuster in a direction of rotation of the rotating heat generation member.

A fixing unit includes: a shaft; a heatable rotating member, mounted for rotation on the shaft, for fixing an image on a recording medium, the heatable rotating member having a heat generating layer heatable via a magnetic flux; a magnetic flux generator configured to generate the magnetic flux, the magnetic flux generator being provided proximal to the heatable rotating member; and a supporting frame having a shaft supporter configured to support an end of the shaft on which the heatable rotating member is mounted, the shaft supporter being positioned outside of an end portion of the magnetic flux generator.

Fixing unit having enhanced heating efficiency and image forming apparatus using the same

A fixing roller and method of manufacturing the same. The fixing roller includes a fixing sleeve configured to fuse and fix a toner image on a recording medium and a fixing assist roller configured to be inserted into the fixing sleeve. The fixing sleeve includes a first heating layer having a Curie point. The first heating layer is configured to be heated with a magnetic flux. The fixing assist roller includes an elastic insulating layer and a first low-resistivity layer. The elastic insulating layer is formed on an outer circumference of the fixing assist roller. The first low-resistivity layer is formed under the elastic insulating layer and has a volume resistivity not greater than 5.0&#xd7;10&#x3a9;m. Convexities and concavities are alternately formed on an outer surface of the elastic insulating layer along a circumferential direction thereof.

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Machida, Japan

Akiko Ito