Kyocera Document Solutions Inc.

Shoko Gon

Akihiro Kondo

Eiji Nakajima

Kenichi Kasama

Kuniaki Nakano

Shinobu Ohata

An image forming apparatus includes an image forming portion, a fixing device, an input portion, and a control portion. The fixing device includes a rotary member to be heated, a pressure-applying rotary member, a heat-applying portion, a pressure-applying mechanism, and a reference position detection mechanism. The control portion controls fixing processing, with the pressure-applying rotary member disposed at any of a plurality of pressure-applying positions and a pressure reduction position based on a type of the recording medium inputted through the input portion. The control portion performs control so that when a prescribed amount of time has elapsed or when a rotation amount of a shaft has reached a prescribed amount from timing at which a reference position detection sensor is brought to an on-state, the pressure-applying drive motor is stopped so as to dispose the pressure-applying rotary member at any of the plurality of pressure-applying positions.

Image forming apparatus

The fixing device () includes the fixing belt (), the pressuring roller () and the pad (). The pad () sandwiches the belt () with the roller () to form the fixing nip. The pad () is extended in the nip width direction, and the pressing face () has the first and second curved faces () and () at upstream and downstream sides in the sheet conveyance direction. The first and second curved faces () and () are formed arch-like curved to the roller () toward upstream and downstream sides. The first and second curved faces () and () continue at the inflection point (B) near the intersection point of the extending line (A) parallel to the pressuring direction and through the rotation center of the roller () on the pressing face (). The first curved face () has the curvature radius (Ra) larger than the second curved face ().

Fixing device and image forming apparatus

A fixing device includes an endless fixing belt, a belt guide, and a frame member. The belt guide has a fastening portion, an arc portion, and a contact portion. The fastening portion is fastened to the frame member. The arc portion extends from the fastening portion while curving in an arc shape along the inner circumferential face of the fixing belt and has an elastic force acting outward in the radial direction. The contact portion extends from one end of the arc portion in the circumferential direction toward the frame member and has a counter-face facing the inner circumferential face of the arc portion. The frame member has a regulating portion that extends toward the belt guide to make surface contact with, so as to overlap, the counter-face of the contact portion.

A fixing device includes a fixing belt, a belt guide, a pressuring member, a heat source and an excessive temperature rise preventing device. The guide contacts with the inside of the belt to assist the belt's rotation track. The heat source is located across the belt to the pressuring member to induction-heat the belt. The preventing device has first and second lead wires connected at one and another end sides in an axial direction of the belt and prevents excessive temperature rise of the guide in noncontact. The first lead wire is extended to one end side and pulled out from the inside to the outside via one end side in the belt. The second lead wire is extended to another end side, curved toward one end side, extended to one end side and pulled out from the inside to the outside via one end side in the belt.

A frequency determining portion determines a driving frequency of an induction heater. A determination processing portion determines whether or not the driving frequency determined by the frequency determining portion is within a predetermined prohibited frequency band. A frequency changing portion, when the driving frequency determined by the frequency determining portion is within the prohibited frequency band and is lower than a predetermined threshold within the prohibited frequency band, changes the driving frequency to a frequency equal to or lower than a lower boundary frequency of the prohibited frequency band, and when the driving frequency is within the prohibited frequency band and is equal to or higher than the threshold, changes the driving frequency to a frequency equal to or higher than a higher boundary frequency of the prohibited frequency band. A heating control portion drives the induction heater by the driving frequency changed by the frequency changing portion.

A fixing device includes a fixing belt, a pressuring member, an exciting coil and a belt guide. The pressuring member comes into pressure contact with the fixing belt to form a fixing nip. The exciting coil is provided at an outer diameter side of the fixing belt and configured to generate a magnetic flux to inductively heat the fixing belt. The belt guide supports the fixing belt from an inner diameter side. The belt guide includes a contact part which is in contact with an inner circumferential face of the fixing belt and a non-contact part which is not in contact with the inner circumferential face of the fixing belt. The non-contact part is provided with a slit configured to inhibit induction heating of the non-contact part due to the magnetic flux generated by the exciting coil.

A fixing device includes a fixing belt, a pressuring member, an exciting coil and a belt guide. The pressuring member comes into pressure contact with the fixing belt to form a fixing nip. The exciting coil is provided at an outer diameter side of the fixing belt and configured to generate a magnetic flux to inductively heat the fixing belt. The belt guide supports the fixing belt from an inner diameter side. The belt guide includes a contact part which is in contact with an inner circumferential face of the fixing belt and a non-contact part which is not in contact with the inner circumferential face of the fixing belt. A magnetic flux blocking member configured to block the magnetic flux that passes through the fixing belt is provided between the fixing belt and the non-contact part.

A fixing device includes a fixing member and an induction heating section. The fixing member fixes an image onto a sheet. The induction heating section inductively heats the fixing member. The induction heating section includes an annular coil and a cover. The annular coil is elongated in a direction perpendicular to a conveyance direction of the sheet. The cover has first, second, and third opening rows. The annular coil includes first and second linear sections. Both the first and second opening rows are located at a side closer to the first linear section than a center line of the annular coil in the longitudinal direction. The second opening row is located closer to the second linear section than the first opening row. The third opening row is located at a side closer to the second linear section than the center line.

Fixing device including induction heating section having cover with opening rows, and image forming apparatus including the same

Provided is a belt member used in a fixing device of an electromagnetic induction heating system. The belt member includes an endless resin base layer, heat layers, and an insulating resin layer. The heat layers are two or more layers including a non-magnetic metal stacked on the resin base layer. The insulating resin layer is an insulating layer stacked between the heating layers.

Belt member, fixing device, and image forming apparatus including the same

A fixing device is provided with a fixing belt, a fixing roller inserted inside the fixing belt, a pressure roller that is pressed against the fixing belt, a coil that generates magnetic flux for induction heating of the fixing belt, and a belt regulating plate that is disposed at a side of an end surface of the fixing roller in a predetermined direction and regulates movement of the fixing belt in the predetermined direction. The belt regulating plate has a multi-layer structure including a resin plate disposed at a fixing belt side and a nonmagnetic metal plate disposed at a side opposite to the fixing belt side.

Fixing device and image forming apparatus provided therewith

A fixing device includes a coil provided along an outer surface of a heating member to generate a magnetic flux for induction heating, a coil holding portion on which the coil is mounted, a core portion that forms a magnetic path around the coil and that includes arch cores that cover an outer side of the coil and are disposed opposite the heating member with the coil interposed therebetween and at a plurality of positions spaced in a recording-medium width direction and a side core that covers the outer side of the coil between the arch cores and the coil holding portion, and a core fixing member that presses the core portion toward the coil holding portion via an elastic member. The core portion is fixed in the pressing state to the coil holding portion by fastening the core fixing member to the coil holding portion.

Fixing device and image forming apparatus including the same

A fixing device includes a heating member, a pressurizing member, a coil wound in a loop shape in the width direction of the heating member to generate a magnetic flux that inductively heats the heating member, and a magnetic core adjacent to the coil. The magnetic core is configured to apply the magnetic flux to an inductive heat-generating layer of the heating member. The magnetic core includes first core parts and second core parts. The first core parts are positioned to enclose the coil in a direction orthogonal to a direction in which paper is conveyed. The second core parts are placed in hollow areas formed by the loops of the coil at both ends in the direction orthogonal to the paper conveyance direction. The second core parts have a higher Curie temperature and a lower thermal capacity than the first core parts.

Image forming apparatus equipped with a fixing device configured to induce electromagnetic heating

A fixing device includes an auxiliary duct. The auxiliary duct is provided between a cover member attached to a coil bobbin so as to cover a magnetic core and a coil, and a core holder provided opposing to the coil bobbin, to which the magnetic core is attached. The auxiliary duct communicates with an intake hole provided at one end in a longitudinal direction of the cover member, and has opening holes overlapping with some of holder opening portions formed on the core holder. The fixing device causes air to flow into between the core holder and the coil bobbin via the auxiliary duct and the holder opening portions from the intake hole, and discharges the air warmed by heat of the coil from an exhaust hole formed at the other end of the cover member, thereby adjusting the flowing amount of air in a longitudinal direction of the coil.

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Osaka, Japan

Shoko Gon