Sharp Kabushiki Kaisha Corporation

Hiroaki Hori

Yoshinobu Tateishi

Atsushi Ide

Toshiya Mikita

Yasunori Minakuchi

Takashi Kubo

Toyoaki Nanba

Motoaki Okitsu

Kohji Aoki

Tatsuya Shinkawa

Toshiaki Kagawa

Susumu Murakami

Tetsunori Mitsuoka

Yasushi Matsutomo

Yasunobu Ohkawa

Noriko Inoue

Yoshinobu Okumura

Yoshiyuki Nagai

Hideki Goto

Koji Aoki

Kohichi Moriyama

A fusing unit is comprised of a pair of rollers, a fusing roller and a pressing roller, having an elastic layer on their outer peripheral surface and a pressing spring for pressing the fusing roller against the pressing roller, and causes a sheet of paper with an unfixed toner image to pass through the nip portion where the fusing roller and pressing roller are put in press-contact with each other so as to fuse the toner image and fix it to the paper. This fusing device further includes a roller member regulator for regulating the press-contact state when the fusing roller and pressing roller are put in press-contact with each other by the pressing spring.

Fusing device and image forming apparatus using the same

In one embodiment, an operation state, standby state or installation environment of an image forming apparatus is detected or determined, and details of heating control of the surface temperature of rollers of a fixing apparatus are changed in accordance with the detected or determined state or environment. For example, when the operation state is a state in which printing on a last sheet of recording paper in a print job is complete, or when the operation state is a state in which printing on recording paper is interrupted, and, in addition, when the installation environment is a low-temperature and low-humidity environment and the image forming apparatus enters the standby state, heating of the rollers is respectively controlled to prevent unexpected and inappropriate changes in the surface temperature of the rollers.

Roller temperature control method of image forming apparatus and image forming apparatus

In one embodiment, the fixing apparatus of the present invention is a fixing apparatus in which while recording paper is transported sandwiched between a heating roller and a pressure roller that are pressed against each other, the recording paper is guided by a guide member, and heat and pressure are applied to the recording paper to fix toner on the recording paper, the fixing apparatus configured with the guide member rotatably provided such that the guide member can be removed from the transport path of the recording paper, and the center of rotational movement of the guide member matched with a shaft of the heating roller or a shaft of the pressure roller.

Fixing apparatus having guide member

In an embodiment of the present invention, a pressure application mechanism portion is provided with a pressure-varying link structure arranged so as to be movable in lateral directions along an upper end portion of a device frame, a drive shaft having an eccentric cam for moving the pressure-varying link structure in the lateral directions, a shaft holding structure arranged so as to be rotatable coupled to the pressure-varying link structure, and a coil spring for applying a biasing force to the shaft holding structure in one direction along the upper end portion of the device frame, and a rotational movement is carried out to make a pressure roller approach and move away from a heat roller so as to achieve a relatively low pressure during a color processing mode and a relatively high pressure during a monochrome processing mode.

Fixing apparatus

A fixing apparatus and an image forming apparatus of the present invention are arranged so that a fixing control section causes a fixing roller to additionally rotate so that the additional rotation corresponds to a driving delay time also after turning OFF an external heating roller heater when shifting from a temperature raising step in which surface temperature of the fixing roller is raised so as to be equal to a preset fixing temperature to a standby mode and when turning OFF the external heating roller heater and stopping the fixing roller. As a result, it is possible to provide a fixing apparatus and an image forming apparatus in which a surface of a fixing roller is free from deterioration or breakage caused by local heating carried out by an external heating roller.

Fixing apparatus and image forming apparatus including the same

A fuser unit including: a set of a heat roller and a pressure roller for sandwiching and conveying a printing sheet while heating the printing sheet by the heat roller; a peripheral surface contact member which is in contact with the peripheral surface of the heat roller; an external heater for heating the peripheral surface contact member by applying electric energy; a contact member temperature sensor for detecting a temperature of the peripheral surface contact member; and a temperature controller for controlling an upper limit temperature of the peripheral surface contact member in accordance with the number of printing sheets conveyed per unit time.

Fuser unit and imaging forming apparatus having the same

A fixing apparatus that fuses and firmly adheres an unfixed developer onto a recording medium includes a heating roller and a pressure roller; a belt-shaped cleaning member that is disposed so as to abut on the heating roller and cleans the surface of the heating roller, the cleaning member being impregnated with oil in advance; a feed roller that sends out the cleaning member; a wind-up roller that winds up the cleaning member having cleaned the heating roller; a press-contact roller disposed so as to press the cleaning member against the heating roller on which the cleaning member abuts; and an oil absorbing layer that is disposed on an outer circumferential surface of the press-contact roller and absorbs oil exudation out of the cleaning member.

In a fixing apparatus that an unfixed developer is fused and fixed by heating/pressurizing a recording medium on which an image of the unfixed developer is formed, a belt-shaped cleaning member is fed from a feeding roller, and the cleaning member is made to respectively contact a heating roller and a pressure roller by a pressure-contact roller, thereby cleaning that the heating roller and the pressure roller, respectively. When a winding roller takes up the cleaning member which has cleaned a roller surface, guide rollers are respectively provided between the pressure-contact roller and the winding roller, and between the feeding roller and the pressure-contact roller so as to contact the cleaning member.

Fixing apparatus having a cleaning member and image forming apparatus having the same

A fixing device includes a feeding roller for feeding a belt-shaped cleaning member which has been rolled up, and a winding roller for taking up the cleaning member which has been fed from the feeding roller and cleaned the surface of the fixing roller. Each of the feeding roller and the winding roller rotates by a time control of a control portion so that a sum of a feed amount of the cleaning member which is fed by the feeding roller at one feeding occasion, and a take-up amount of the cleaning member which is taken up by the winding roller at one take-up occasion, is equal to or more than a double of a length Ln of a nip section.

Fixing device for fusing and fixing an unfixed developer onto a recording medium, and image forming device having the same

A fixing device includes a feeding roller for feeding a belt-shaped cleaning member which has been rolled up, and a winding roller for taking up the cleaning member which has been fed from the feeding roller and cleaned a surface of the fixing roller, the winding roller being provided so as to pressure-contact the feeding roller. The winding roller is rotated by a time control due to a control portion so that a sum of a feed amount of the cleaning member which is fed by the feeding roller at one feeding occasion, and a take-up amount of the cleaning member which is taken up by the winding roller at one take-up occasion, is equal to or more than a double of a length Ln of a nip section.

Fixing device and image forming apparatus having the same

A sheet delivery mechanism designed to discharge successive sheets to different delivery positions includes offset rollers, an offset unit, an offsetting force generator and an offset unit swinging mechanism. The offset rollers is rotatably supported by the offset unit to discharge each sheet in a sheet transport direction. The offsetting force generator produces a driving force for shifting the offset unit back and forth along a direction perpendicular to the sheet transport direction between a reference position and offset positions. The offset unit swinging mechanism swings the offset unit about an axis parallel to rotary shafts of the offset rollers in such a manner that a sheet output direction in which the offset rollers eject each sheet varies to a direction pointing away from a sheet delivery tray when the offset unit is shifted along the direction perpendicular to the sheet transport direction by the offsetting force generator.

Sheet delivery mechanism

A heating device for heating a recording sheet. The heating device has a first heater located within a heating roller. The first heater has a heat distribution effective to form a low temperature region in an axially central portion of the heating roller and a high temperature region in each of axially opposite end portions of the heating roller. There is a second heater located within the heating roller that has a heat distribution effective to form a high temperature region in the axially central portion of the heating roller, a low temperature region in each of the opposite end portions of the heating roller, and a second-level high temperature region in each of axially opposite end portions of the high temperature region, the second-level high temperature region being lower in temperature than the high temperature region.

Heating roller of a fixing device with two internal heaters for axial heat distribution

A prior art temperature sensing element by supporting plates against a fixing roller would detect a temperature lower than an actual surface temperature of the fixing roller, because said heat-conductive supporting plates would be cooled by air flowing along said supporting plate, depriving a part of its heat of the temperature sensing element through the supporting plate. According to present invention, a heat-insulating elastic body is disposed over said two supporting plates at one end threof, said temperature sensing element is placed as being projecting from the surface of the heat-insulating elastic body at the center thereof, the temperature sensing element and supporting plates are fastened (sticked) with the heat-resisting film larger in length and wide than the heat-insulating elastic body and each having an adhesive surface one side thereof, and the other end of each supporting plate is secured to a holder.

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Kyoto, Japan

Hiroaki Hori