Ricoh Company, Ltd.

Takahiro Yoshikawa

Masami Tomita

Naoki Iwaya

Akira Shinshi

Hitoshi Ishibashi

Masahiko Satoh

Yuuji Sawai

Takayuki Maruta

Setsuo Soga

Toshiharu Hachisuka

Ken Omura

Yasuhiro Kohira

Masamichi Yamada

Atsushi Takehara

Shinji Etoh

A fixing device includes a separator disposed downstream from a fixing nip formed between a fixing rotary body and a pressing rotary body in a recording medium conveyance direction to separate a recording medium from the fixing rotary body. The separator includes a front disposed opposite an outer circumferential surface of the fixing rotary body with a given interval therebetween and a conveyance face contiguous to the front, over which the recording medium slides. A coating layer, made of fluoroplastic, coats the front and the conveyance face of the separator. The coating layer includes a front portion corresponding to the front of the separator and produced with a plurality of recesses extending in a width direction of the separator orthogonal to the recording medium conveyance direction throughout substantially an entire width of the separator in the width direction thereof.

Fixing device and image forming apparatus incorporating same

An image forming apparatus includes a gloss applying mode for applying gloss to an image on a sheet and a non-gloss-applying mode. The image forming apparatus includes a fixing device including a fixing member and a pressurizing member that is pressed into contact with the fixing member to form a fixing nip portion in which toner is fixed to the sheet; and a gloss applying device including a first roller including a heating unit and a second roller that is pressed into contact with the first roller to form a gloss applying nip portion in which gloss is applied to the toner. The fixing device and the gloss applying device are provided on a sheet conveying path line. When the sheet is conveyed in the non-gloss-applying mode, nip pressure of the gloss applying nip portion in the gloss applying device is lower than that in the gloss applying mode.

Image processing apparatus including a gloss applying device

A fixing device including a fixing member to fix a toner image on a sheet by application of heat and pressure and a pressing member to press the sheet against the fixing member. The pressing member is rotatable. A height difference is circumferentially provided to the pressing member, and is tapered from an end portion toward a portion contacting an edge of a small-size sheet. The pressing member has a greater hardness than the fixing member.

Fixing device and image forming apparatus in which a height difference is circumferentially provided to a pressing member

The fixing device includes a fixing roller, a separation roller, an endless fixing belt, and a pressing roller. The fixing roller includes a first elastic layer as a surface layer and has a roller hardness A. The separation roller includes a second elastic layer as a surface layer and has a roller hardness B smaller than the roller hardness A of the fixing roller. The endless fixing belt is wound around the fixing roller and the separation roller. The pressing roller is pressed against the fixing roller and the separation roller via the fixing belt to form a nip portion between the fixing belt and the pressing roller through which the recording medium bearing the toner image passes. The pressing roller includes a third elastic layer as a surface layer and has a roller hardness C not smaller than the roller hardness A of the fixing roller.

A fixing device includes a fuser member, a pressure member, a first motor, a second motor, a pressure adjuster, and a controller. The fuser member defines a first heatable surface. The pressure member defines a second heatable surface. The first motor is connected to the fuser member to rotate at a first rotation rate to drive the first surface at a first conveyance speed. The second motor is connected to the pressure member to rotate at a second rotation rate to drive the second surface at a second conveyance speed. The pressure adjuster presses the pressure member against the fuser member at a variable pressure to form a fixing nip with a variable width extending along the conveyance path. The controller is connected to the first and second motors to adjust at least one of the first and second rotation rates relative to the other.

A fixing device includes a first driving system connected to a fixing roller and a separation roller and a second driving system connected to a pressing roller pressed against the fixing roller and the separation roller via a fixing belt. In the first driving system, a first transmission transmits a first driving force generated by a first motor to the fixing roller and the separation roller, and includes a first one-way clutch via which the first driving force is transmitted to the fixing roller. In the second driving system, a second transmission transmits a second driving force generated by a second motor to the pressing roller. When a circumferential velocity of the pressing roller is greater than a circumferential velocity of the fixing roller, the first one-way clutch idles to rotate the fixing roller in accordance with rotation of the pressing roller.

An image forming apparatus includes an image carrying member, a transfer unit, a pre-heating unit, a fixing unit, a first temperature sensor, and a first heat controller. The image carrying member carries a toner image. The transfer unit transfers the toner image carried on the image carrying member to a recording medium transported to a transfer position. The pre-heating unit selectively heats the recording medium before the recording medium is transported to the transfer position. The fixing unit fixes the toner image on the recording medium. The first temperature sensor detects temperature of the recording medium as the recording medium passes through the pre-heating unit. The first heat controller changes an amount of heat energy to be applied to the recording medium per unit area of the recording medium by the pre-heating unit. The first heat controller is controlled based on a detection result of the first temperature sensor.

Image forming apparatus including pre-heating unit

In a fixing device for fixing a toner image on a recording medium, a fixing roller and a heating roller support a fixing belt. A pressing roller presses against the fixing roller via the fixing belt to form a fixing nip between the fixing belt and the pressing roller. A tension roller presses against the fixing belt to apply tension to the fixing belt. A primary heat source heats the fixing belt, and is disposed along an outer face of the fixing belt opposite the heating roller. A secondary heat source is provided inside the tension roller to supply deficient heat not provided by the primary heat source.

Fixing device using induction heating and image forming apparatus using the fixing device

A fixing device, an image forming apparatus using the fixing device, and a temperature control method therefor. The fixing device includes a fixing roller, a heat roller including first and second heat sources, a fixing belt, a pressure roller including a pressure heat source, a first temperature detector, a second temperature detector, and a pressure temperature detector. The heat sources are regularly on and off according to a duty cycle, and at least one of the heat sources is controlled by the duty cycle during paper feed. A wattage of one of the heat sources is added to a wattage of at least one of the other heat sources when the temperature detected by the first or second temperature detector corresponding to the one of the heat sources reaches the set temperature such that a duty ratio of the at least one of the other heat sources is increased.

Fixing device having heaters controlled based on temperatures detected by first and second temperature detectors

An image fixing apparatus includes a fixing member, a magnetic flux generator, a heat member, a core, and a magnetic flux adjuster. The fixing member fixes the toner image onto the recording medium. The magnetic flux generator generates a magnetic flux. The heat member has a heat layer which is heated inductively by the magnetic flux generated by the magnetic flux generator and heats the fixing member. The core faces the magnetic flux via the heat member. The magnetic flux adjuster is configured to vary a heating range of the heat member in the width direction. The heat layer has a predetermined Curie point.

Image fixing apparatus and an image formation apparatus including a magnetic flux adjuster

A fixing device, including a fixing rotary body including a first heat source, a pressing rotary body including a second heat source, and a control device configured to cause, at a time of warm-up of the fixing device, the fixing rotary body to rotate while causing at least one of the first heat source and the second heat source to generate heat, and to allow, after a surface temperature of the fixing rotary body has risen to a preselected warm-up temperature, a sheet pass or a printing to be executed and cause, if a sheet pass is not executed, the fixing rotary body to rotate for a preselected period of time.

Fixing device to reduce warm-up time and apparatus using same

An image forming apparatus includes an image forming device configured to form a toner image on a sheet and a fixing device configured to fix the toner image on the sheet. In the fixing device, a heater heats a fixing belt. A pressing roller applies a pressure to a fixing roller via the fixing belt to form a nip between the pressing roller and the fixing belt. A controller switches the fixing device between an increased pressure mode and a decreased pressure mode in a state in which the fixing roller and the pressing roller rotate. In the increased pressure mode, the pressing roller applies an increased pressure capable of fixing the toner image on the sheet to the fixing roller. In the decreased pressure mode, the pressing roller applies a decreased pressure incapable of fixing the toner image on the sheet to the fixing roller.

Image forming apparatus, fixing device, and image forming method

A belt type fixing device includes a fix roller, a press roller rotatable in pressing contact with the fix roller, a heat roller accommodating a heat source therein and a belt passed over the fix roller and heat roller. A non-contact type temperature sensor is positioned in a sheet passing range corresponding to the width of a minimum sheet size and assigned to the heat roller while a contact type temperature sensor is positioned outside of the sheet passing range. A controller prevents the heat source from being turned on if a temperature sensed by the non-contact type temperature sensor is short of a preselected temperature B when a temperature sensed by the contact type temperature sensor reaches a preselected temperature A assigned to the non-contact type temperature sensor. A reflection type sheet sensor determines whether or not a sheet is present on the belt.

Belt type fixing device including a contact and a non-contact temperature sensor and a reflection type sheet sensor

An image forming apparatus includes a first heater that heats a heating member, a second heater that heats a support member, and a third heater that heats a facing member. The image forming apparatus further includes a fixing belt wound around between the heating member and the support member, and a facing member arranged so as to face the fixing belt. A paper is passed through a nip portion between the facing member and the fixing belt and a toner image is fixed on the paper by applying heat and pressure to the toner of the toner image. Only the first heater is energized during the fixing operation. All the three heaters are energized at the time of startup operation and during a standby state.

Fixing apparatus and image forming apparatus

A belt fixing unit, an image forming apparatus, and a toner material are disclosed capable of obviating undesirable fixing belt deformation and low image quality. The belt fixing unit includes a fixing roller, a heating roller, a fixing belt, and a pressing roller in contact with the fixing roller to form a fixing nip having the fixing belt intervening there between, the fixing belt including at least a base member formed of a heat-resisting resin having a thickness of 90 &#x3bc;m or smaller and acted upon by a tensile force of 0.49 N/mm or less. The toner is a low-melting point toner formed by subjecting a toner preparatory solution containing at least a prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant and a releasing agent dispersed in an organic solvent to extension and/or crosslinking reactions in an aqueous medium.

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Kanagawa, Japan

Takahiro Yoshikawa