Fixing device, image formation apparatus, and method of manufacturing fixing roller
AssigneeOki Data Corporation
InventorMasahiko Shimosugi
Life of this patent
Estimating the term…
Abstract
A fixing device includes a fixing roller configured to be heated by a heat source, and a pressure roller configured to be in pressure-contact with the fixing roller. The fixing roller includes a cylindrical tubular core having an inner circumferential surface and one or more ribs protruded from the inner circumferential surface and extending spirally along the inner circumferential surface. The total number of times that the one or more spiral ribs cross through a region of contact between the fixing roller and the pressure roller is more than one, regardless of a rotation angle of the fixing roller.
Claims10
A fixing device comprising:
- a fixing roller configured to be heated by a heat source;
- and
- a pressure roller configured to be in pressure-contact with the fixing roller, wherein
- the fixing roller includes a cylindrical tubular core having an inner circumferential surface and at least one spiral rib protruding from the inner circumferential surface and extending spirally along the inner circumferential surface, and
- the total number of times that the at least one spiral rib crosses through a region of contact between the fixing roller and the pressure roller is more than one, regardless of a rotation angle of the fixing roller,
- wherein the at least one spiral rib has a lead angle at an axial middle region of the fixing roller smaller than a lead angle at an axial end region of the fixing roller, wherein the lead angle is an angle of the at least one spiral rib with respect to a plane extending orthogonal to an axis of the cylindrical tubular core.
A fixing device comprising:
- a fixing roller configured to be heated by a heat source;
- and
- a pressure roller configured to be in pressure-contact with the fixing roller, wherein
- the fixing roller includes a cylindrical tubular core having an inner circumferential surface and at least one spiral rib protruding from the inner circumferential surface and extending spirally along the inner circumferential surface,
- the total number of times that the at least one spiral rib crosses through a region of contact between the fixing roller and the pressure roller is more than one, regardless of a rotation angle of the fixing roller,
- the cylindrical tubular core includes a U-shaped groove configured to engage with a gear configured to transmit a driving force,
- the U-shaped groove is defined by paired sidewall surfaces and a connection surface connecting the paired sidewall surfaces with each other, and
- one of the sidewall surfaces of the U-shaped groove extends along a part of the at least one rib.
A method of manufacturing a fixing roller including a cylindrical tubular core, comprising:
- extruding a heated ingot billet made of an aluminum alloy through an opening of a die having a cross-sectional shape substantially equivalent to a cross-sectional shape of the cylindrical tubular core, and thereby forming an extruded original pipe;
- and
- drawing the extruded original pipe through a gap between an outer-diameter tool and an inner-diameter tool which define the cross-sectional shape of the cylindrical tubular core, and thereby obtaining the cylindrical tubular core with the cross-sectional shape, wherein
- in the drawing step, the original pipe is drawn while being rotated to obtain the cylindrical tubular core having a spiral rib formed on an inner circumferential surface of the cylindrical tubular core,
- wherein the original pipe is drawn while being rotated with a varying rotation speed.
Dependencies are inferred from the claim text.