Minolta Company, Ltd.

Eiji Okabayashi

Yuusuke Morigami

Takeshi Kato

Satoru Yoneda

Tetsuro Ito

Taizou Oonishi

Mitsuru Isogai

Toshio Sakata

Yoshifumi Kosagi

Hiroaki Hinotani

Noboru Yonekawa

Mikiyuki Aoki

Takashi Yamada

Tatsumi Fujishima

Tohru Fujiwara

Peter Johnston

Shigeo Honma

Takashi Kidokoro

Ryo Kawamura

A belt type fixing device of the invention comprises a fixing belt, a heating panel, a pressure member, and a pressure roller. The heating panel has a curved outer surface in sliding contact with the inner surface of the fixing belt and a curved inner surface on which a resistance heating band element is formed. The resistance heating band element is formed in a zigzag pattern with a plurality of stripes perpendicular to the direction in which the fixing belt moves. The pressure member gives tension to the fixing belt in cooperation with the heating panel and has an elastic body in sliding contact with the inner surface of the fixing belt. The pressure roller rotating in a predetermined direction applies pressure to toner carrying recording paper led into a nip formed by the pressure roller and the pressure member.

Belt type fixing device

A belt-type fixing device for an image forming apparatus is capable of raising a temperature to a level suitable for a fixing process in a short period of time with high heating efficiency. A fixing belt is entrained in spanning relation between a heating plate providing a heat generator on the inner surface of the semi-cylindrical plate and a pressing pad disposed at a distance from the heating plate. A pressing roller is disposed at a position opposing the pressing pad. The fixing belt is revolved by rotating the pressing roller. A recording medium having a toner adhered thereto is caused to pass through a nip portion of the fixing belt and the pressing roller.

Fixing device for image forming apparatus

A metal sheet showing either voltage characteristics, impedance or calorific characteristics close to the case where low frequency is applied even when a high frequency alternating current voltage is applied. This metal sheet presents a good movement of displacement and less starting points of cracking, because of its good crystallinity (good mobility of conductive electrons). Therefore, it is hardly destroyed under the repeated deformation. In short, it presents a high fatigue resistance against repetitive deformation. Therefore, this metal sheet is suited for a fixing belt and a fixing apparatus. The evaluation of fatigue resistance using this can be realized by comparing voltage characteristics, impedance, or calorific characteristics when high and low frequency alternating current voltages are applied to a test piece.

High fatigue resistant metal sheet and fixing belt and fixing apparatus using the same and evaluation apparatus of metal material fatigue resistance and method thereof

A fixing belt is applied to a fixing apparatus of an electronic photography type printer. The fixing belt consists of a belt base and an elastic layer having a thickness of 200 .mu.m or more formed on the belt base. The elastic layer consists of first, second and third elastic layers arranged in that order from the base side, and is deformable to conform to the surface shape of a recording paper so that all unfixed toner held on the recording paper can be pressed. The second elastic layer is a barrier layer for preventing releasing agent from permeating and the belt from swelling to suppress the thickening of the elastic layer as a whole and maintain the belt thickness within a range that does not cause any image noises.

Fixing belt, fixing apparatus equipped with fixing belt, and method of

A heating device comprises an endless rotary member, a resistance heating member, a current receiver member provided at the endless rotary member and a current supply member being in contact with the current receiver member. In a form, the current supply member is made of a sintered material containing copper and carbon, and a content of the copper in the sintered material is in a range from 55% to 80% by weight. In another form, a contact surface of the current receiver member is formed of a material harder than the current supply member. The contact surface of the current receiver member and the contact surface of the current supply member have surface roughnesses satisfying a relationship of (surface roughness of the current receiver member).ltoreq.(surface roughness of the current supply member). The surface roughness Ra of the current receiver member is in a range from 0.3 .mu.m to 5.5 .mu.m. The surface roughness Ra of the current supply member is equal to or smaller than 5.5 .mu.m.

Heating device

A heating device comprises an endless rotary member having a peripheral surface to be moved rotatively, a resistance heating member arranged at the peripheral surface of the rotary member and generating a heat when supplied with an electric current, a current receiver member arranged in a space inside the rotary member and electrically connected to the resistance heating member, and a current supply member being in contact with the current receiver member and to be electrically connected to a power source. A heating rotary member for the heating device comprising the endless rotary member, the resistance heating member, and the current receiver member.

Heating device and heating rotary member

An induction heating fixing device is disclosed which is provided with a conducting sleeve, a coil for causing the sleeve to generate an induced current, and a high-frequency power source for feeding a high-frequency wave to the coil. This fixing device detects the switching cycle of the high-frequency power source and the electric power injected into the sleeve and, based on the detected switching cycle and the detected electric power, controls the amount of electric current to be fed from the high-frequency power source to the coil.

Apparatus and method for detecting a condition in an inductive heating

In a fixing apparatus having a flexible metal fixing sleeve provided around a holder, which holds a coil inside, and heated by induction current of the coil, and a pressure roller that pinches the fixing sleeve between it and the holder by pressing on the holder, the following relation is satisfied:

Apparatus for controlling the rotational motion of a fixing apparatus

A fixing apparatus for controlling an oil transfer apparatus to maintain a releasing agent holding layer such that it is not always saturated with the releasing agent. This makes it a compact, cost-effective unit with a long service life and provides a uniform, stable oil coating that eliminates image noise problems. In order to use a constant and minimum necessary amount of releasing agent, a releasing agent supply nozzle is incorporated with multiple protrusive or retrusive droplet growth assisting members at or near multiple releasing agent discharge ports. The supply nozzle used for supplying the oil has multiple discharge holes having approximately equal opening cross-sectional areas and an equalizing member which equalizes the amount of oil discharged from each discharge hole. The outer diameter D1 of the oil supply roller, the outer diameter D2 of the metal core and the distance P of adjacent through-holes formed on the periphery of the metal core satisfy a relation, 0.6&lt;D1.multidot.(D1-D2)/(D2.multidot.P)&lt;6. A quantifying apparatus is provided to equalize the amount of oil transferred by the oil pump when it is intermittently transferred. The quantifying apparatus contributes in achieving a constant amount of releasing agent coating. A releasing agent leakage prevention member is provided to prevent unnecessary oil leakage from the releasing agent supply nozzle and rollers. A specific correlation is established between the centerline average roughness of the oil supply roller surface and the amount of the releasing agent supply to the fixing roller by the oil supply roller. This makes it possible to achieve a uniform coating with excellent releasing capability and prevents adhesion of add particles.

Fixing apparatus including apparatus for controlling the supply of

A fixing apparatus that supports an endless belt by rollers, forms a nipping area with a pressuring roller contacting outside periphery of the belt, and fixes unfixed images on sheets that are transported into the nipping area, the fixing apparatus characterized in that transportation of the sheets into the nipping area is prohibited until the minimum belt temperature detected by a temperature sensor reaches a fixing approval temperature.

Fixing apparatus having a transport mechanism and a controller for

This invention is related to a power supply unit used in an image forming apparatus having a induction heat fusing device. In the power supply unit, each of a first and a second rectifying circuits rectifies AC voltage from a power supply to generate DC voltage. An inverter circuit generates a high frequency voltage to be applied to a coil of the induction heat fusing device by switching the DC voltage from the first rectifying circuit. A switching circuit switches the DC voltage from said second rectifying circuit and generates AC voltage. A transformer receives the AC voltage from the switching circuit and outputs a transformed voltage to be apply to a component of the image forming apparatus. The inverter, second rectifying circuit and switching circuit are connected to a common ground line.

Power supply unit capable of high frequency switching for powering an

An induction heating fixing apparatus is disclosed which in characterized by comprising an object to be heated formed of an electroconductive material, a coil for effecting induction heating on the object to be heated, an inverter circuit for effecting the flow of a high frequency to the coil, a thermistor for detecting the temperature of the object to be heated, a control circuit electrically insulated from the inverter circuit and adapted to control the inverter circuit based on the temperature detected by the thermistor so as to keep the object to be heated at a temperature in a prescribed range, and an insulating switch for transmitting the control signal from the control circuit in an electrically insulated state to the inverter circuit.

Induction heating fixing apparatus

A fixing device for heating and fixing an unfixed image to a record member, including: a heating roller having a core roller and a layer of a resistance heating material formed on an outer or inner peripheral surface of the core roller; a pair of carriers rotatably carrying the heating roller; a pair of ring-shaped current receiver members each located between the carrier and a center of the heating roller, a pair of current supply members being in contact with the current receiver members; and insulating members made of an electrical insulation material, each being in contact with an outer end of the current receiver member and extending toward the carrier, wherein a distance L3 from the inner end of the carrier to the outer end of the current receiver member is 1 mm or more, a sum (L1+L2) of a width L1 of the insulating member and a height L2 of the insulating member from the core roller is 2.5 mm or more, and the distance L3 and the width L1 satisfy a relationship of L3.gtoreq.L1. A heat-resistant electrical insulation layer may cover the surface of the resistance heating material layer and a temperature sensing element may be provided, a portion of the element being in contact with the heat-resistant electrical insulation layer of the heating roller and covered with a heat-resistant electrical insulation layer. Each of the heat-resistant electrical insulation layers has a breakdown voltage of 3000 V or more.

Fixing device

The present invention is related to a fixing device for fusing and fixing an unfixed toner image on a recording sheet. In the fixing device, a heating member such as rollers and endless belts and the like, is heated to a fixing temperature. An endless belt is provided opposite the heating member and is pressed against the heating member by a pressure member provided inside the endless belt. The heating member is driven in rotation in a transport direction of the recording sheet and the endless belt is driven in conjunction with the rotation of the heating member. The recording sheet bearing a toner image passes between the heating member and the endless belt while in this state, and the toner image is heated by the heating member so as to be fused onto the recording sheet under the pressure produced between the heating member and endless belt while the recording sheet is transported therebetween.

Fixing device and fixing method

An induction heating type fixing apparatus comprises a fixing sleeve formed of a flexible thin electrically conductive magnetic material, a coil for producing an induced eddy current in the fixing sleeve to generate heat therein, a holder adapted to retain the coil and disposed stationarily in the fixing sleeve, and a pressing roller pressed against the holder through the fixing sleeve. A sheet carrying thereon an unfixed toner is conveyed as nipped between the fixing sleeve and the pressing roller. The toner on the sheet is melted by the heat of the sleeve itself and exposed to the pressure exerted between the holder and the pressing roller and fixed on the sheet. The holder is provided with a separating member adapted to effect the curvature separation of the sheet from the fixing sleeve. The holder is further provided with a heat-diffusing member made of a material with good thermal conductivity characteristics and non-magnetic properties.

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Toyokawa, Japan

Eiji Okabayashi