Fixing device and image forming apparatus
AssigneeKyocera Mita Corporation
InventorYuzuru Nanjo
Life of this patent
Estimating the term…
Abstract
An image forming unit (40) of a copier (1) is provided with an image fixing unit (fixing device) (47) adopting an induction heating method. A heating roller (47a) of this image fixing unit (47) includes a heat producing layer (47d) made of a temperature-sensitive magnetic material whose permeability changes with temperature, and a supporting layer (47e) disposed adjacent to the heat producing layer (47d) and made of a nonmagnetic and electrically conductive material. The heat producing layer (47d) has a width substantially equal to a passing area (L1) (about 294 mm) for (A3) sheets along a direction of an axis of rotation of the heating roller (47a) and smaller than a width (L3) (about 310 mm) of an induction heating coil (47c).
Claims12
A fixing device for fixing a toner image transferred to the front face of a sheet to the sheet by heat, comprising:
- a heating roller for producing heat by an induction heating method,
- a pressure roller disposed in such a manner that can be pressed into contact with the heating roller, and
- an induction coil for increasing the temperature of the heating roller,
- the sheet having the toner image transferred thereto being passed through a contact portion between the heating roller and the pressure roller to have the toner image fixed thereto by the heat produced by the heating roller,
- wherein the heating roller includes:
- a first layer made of a temperature-sensitive magnetic material whose permeability changes with temperature, and
- a second layer provided adjacent to the first layer and made of a nonmagnetic and electrically conductive material,
- the first layer having a width larger than a sheet passing area and smaller than the width of the induction coil along a direction of an axis of rotation of the heating roller.
An image forming apparatus, comprising:
- a transferring unit for transferring a toner image to a sheet based on an image data, and
- an image fixing unit for fixing the toner image transferred to the front face of the sheet in the transferring unit to the sheet by heat, the image fixing unit comprising:
- a heating roller for producing heat by an induction heating method,
- a pressure roller disposed in such a manner that can be pressed into contact with the heating roller, and
- an induction coil for increasing the temperature of the heating roller,
- the sheet having the toner image transferred thereto being passed through a contact portion between the heating roller and the pressure roller to have the toner image fixed thereto by the heat produced by the heating roller,
- wherein the heating roller includes:
- a first layer made of a temperature-sensitive magnetic material whose permeability changes with temperature, and
- a second layer provided adjacent to the first layer and made of a nonmagnetic and electrically conductive material,
- the first layer having a width larger than a sheet passing area and smaller than the width of the induction coil along a direction of an axis of rotation of the heating roller.
Dependencies are inferred from the claim text.