Canon Kabushiki Kaisha

Yuko Sekihara

Hiroyuki Sakakibara

Hiroaki Sakai

Masaaki Takahashi

Kazuo Kishino

Katsuhisa Matsunaka

Norio Hashimoto

Atsushi Iwasaki

An image forming apparatus includes an image forming unit, a fixing unit, and a power control unit. The image forming unit forms an unfixed image on a recording material. The fixing unit includes an endless belt, a heater held in contact with the endless belt, a pressurization roller to form a fixing nip portion for pinching and conveying the recording material together with the heater via the endless belt, and a pressure changing mechanism to effect switching between a pressurization state and a pressure release state. The power control unit controls power to the heater. In response to transitioning from the pressure release state to the pressurization state, the power control unit starts power to the heater during a transition period before the pressurization state is attained and controls power to the heater such that a heater temperature does not exceed a predetermined upper limit temperature during the transition period.

Image forming apparatus with heater

A pressing roller includes a metal core and an elastic layer containing a needle-like filler which has an average length of 0.05 mm or more and 1 mm or less and a thermal conductivity of 500 W/(mK) or more. In the elastic layer, pore portions are dispersed.

Pressing roller and image heating device using the pressing roller

The image heating apparatus includes a rubber layer and a resin tube layer on a metal core. The rubber layer includes a solid rubber layer having a thermal conductivity in a thickness direction of 0.16 W/(m&#xb7;K) or more and 0.40 W/(m&#xb7;K) or less, and a self-bonded silicone rubber layer that contains a filler of 5 vol % or more and 40 vol % or less, and has a thermal conductivity in an axial direction of 2.5 W/(m&#xb7;K) or more and a thickness of 0.5 mm or more and 5.0 mm or less, the filler having a length of 0.05 mm or more and 1 mm or less and a thermal conductivity in a length direction of 500 W/(m&#xb7;K) or more, so that a pressure roller to moderate temperature rise in a non-sheet feeding area when a small sized recording material has undergone sheet feeding can be easily manufactured.

Image heating apparatus, pressure roller to be used in the image heating apparatus, and manufacturing method for the pressure roller

A pressing member for creating a nip in which the pressing member contacts a heating member and a recording material is heated while being nip-conveyed, includes an elastic layer and a high thermal conductive elastic layer, which is provided on the elastic layer and has a thermal conductivity which is higher than that of the elastic layer. In the high thermal conductive elastic layer, carbon fibers and carbon nanofibers are dispersed in a heat-resistant elastic material.

Pressing member and image heating member using the pressing member

A pressure roller forms a nip for contacting a heating member to pinch and convey a heat recording material. The roller includes a core metal and an elastic layer containing filler. The elastic layer containing the filler includes thermal conductive filler with a length of not less than 0.05 mm and not more than 1 mm with a thermal conductivity &#x3bb;in the longitudinal direction in a range of &#x3bb;&#x2267;500 W/(m&#xb7;k), being dispersed in not less than 5 vol % and not more than 40 vol %. The elastic layer containing the filler has a thermal conductivity &#x3bb;in the longitudinal direction perpendicular to a recording material conveyance direction, of &#x3bb;&#x2267;2.5 W/(m&#xb7;k) and an ASKER-C hardness of the filler is not more than 60 degrees. A solid rubber elastic layer with a thermal conductivity &#x3bb; in a thickness direction of not less than 0.16 W/(m&#xb7;k) and not more than 0.40 W/(m&#xb7;k) is included.

Image heating apparatus and pressure roller used for image heating apparatus

A pressure roller forms a nip for contacting a heating member to pinch and convey a heat recording material. The roller includes a core metal and an elastic layer containing filler. The elastic layer containing the filler includes thermal conductive filler with a length of not less than 0.05 mm and not more than 1 mm and with a thermal conductivity &#x3bb;in the longitudinal direction in a range of &#x3bb;&#x2267;500 W/(m&#xb7;k), being dispersed in not less than 5 vol % and not more than 40 vol %. The elastic layer containing the filler has a thermal conductivity &#x3bb;in the longitudinal direction perpendicular to a recording material conveyance direction, of &#x3bb;&#x2267;2.5 W/(m&#xb7;k) and an ASKER-C hardness of the filler is not more than 60 degrees. A solid rubber elastic layer with a thermal conductivity &#x3bb; in a thickness direction of not less than 0.16 W/(m&#xb7;k) and not more than 0.40 W/(m&#xb7;k) is included.

A pressure member contacts a heating member to form a nip part where a recording material is heated and pinched-conveyed, and includes a first elastic layer and a second elastic layerhaving a higher thermal conductivity than that of the first elastic layer. An elastic layer is formed of a combination of the first elastic layer and the second elastic layer so that the thickness of the second elastic layer at the end portion is thicker than the thickness of the second elastic layer at the center portion in a longitudinal direction perpendicular to a recording material conveyance direction. Accordingly, when using the pressure member to contact the heating member to form the nip part, it is possible to reduce the difference between a center nip width and an end-portion nip width of the nip part.

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Tokyo, Japan

Yuko Sekihara