Abstract: A heating device includes a belt member, plural heating elements, and plural resistance elements. The belt member is rotated. The plural heating elements are arranged in a width direction of the belt member and generate heat so as to heat the belt member. The plural resistance elements having positive temperature coefficients are each connected in series with a corresponding one of the plural heating elements. In the heating device, a temperature of the belt member is reduced by an increase in resistances of the plural resistance elements caused by an increase in temperatures of the plural resistance elements.

Abstract: A fixing device includes an endless belt member, a fixed member that is in contact with an inner circumferential surface of the belt member, a heating member configured to heat the belt member, and a pressing member including at least a pressing roller that includes an elastic surface layer and presses the belt member against the fixed member from an outer circumferential side of the belt member in such a manner as to form a fixing part through which a recording object carrying an unfixed image is made to pass. A center, in a direction of rotation of the pressing roller, of a contact part of the fixed member that is in contact with the pressing roller through the belt member resides at a position that is displaced toward an entrance side of the fixing part with respect to a center of rotation of the pressing roller.

Abstract: A heating device includes a belt member, plural heating elements, and plural resistance elements. The belt member is rotated. The plural heating elements are arranged in a width direction of the belt member and generate heat so as to heat the belt member. The plural resistance elements having positive temperature coefficients are each connected in series with a corresponding one of the plural heating elements. In the heating device, a temperature of the belt member is reduced by an increase in resistances of the plural resistance elements caused by an increase in temperatures of the plural resistance elements.

Abstract: A fixing device includes an endless belt member, a secured member disposed to contact the belt member, a heating unit that heats the belt member, and a rotary pressurizing roller including an elastic layer that is elastically deformed when the belt member is pressed against a pressing surface of the secured member to form a fixing part. The pressurizing roller is curved such that a center portion is smaller in outside diameter than end portions along the axial direction. The pressing surface is curved such that a center portion projects toward the pressurizing roller more than end portions along the longitudinal direction. On the pressing surface, an amount of projection of the center portion with respect to the end portions along the longitudinal direction is set to be larger on an output side than on an input side of the fixing part along a moving direction of the belt member.

Abstract: A fixing device includes a belt, a secured member, a support roller, a heating unit, and a pressure roller that is driven to rotate and has an elastic surface layer deformed when pressing the belt against the secured member so as to form a fixing portion. A recording medium that holds an unfixed image passes through the fixing portion. The secured member has a contact portion and an insertion portion having first and second curved surfaces respectively curved toward first and second sides opposite to each other. Conditions t(1/r1+1/r2)?0.130 and r1<r2 are satisfied where t denotes a thickness of the belt, r1 denotes a radius of curvature of the second curved surface in mm, and r2 denotes a radius of curvature of the first curved surface in mm.

Abstract: A fixing device includes: an endless belt member; a secured member disposed to contact the belt member; a support roller that rotatably supports the belt member; a heating unit that heats the belt member; and a rotary pressurizing roller that includes an elastic surface layer that is elastically deformed when the belt member is pressed against the secured member to form a fixing part. The secured member includes a recessed part provided on a surface of the secured member that faces the pressurizing roller and configured to curve the belt member into a recessed shape, projecting parts provided upstream and downstream of the recessed part, respectively, and configured to curve the belt member into a projected shape, and a region provided between at least one of the projecting parts and the recessed part and having a small curvature compared to the corresponding projecting part.

Abstract: A fixing device includes a rotatable endless belt, a heating source that heats the belt, a pad member having a sliding surface abutting on an inner surface of the belt, and a pressure roller that presses an outer surface of the belt toward the sliding surface and rotates to rotate the belt. The pressure roller works together with the belt to fix an unfixed toner image onto a medium that bears the unfixed toner image by allowing the medium to enter between the roller and the belt. Assuming that the sliding surface is divided into upstream and downstream regions in a moving direction of the belt, the upstream and downstream regions both have recessed curved surfaces in the moving direction. A first curved surface corresponding to the upstream region has an average curvature that is larger than that of a second curved surface corresponding to the downstream region.

Abstract: A fixing device includes an endless belt member, a fixed member that is in contact with an inner circumferential surface of the belt member, a heating member configured to heat the belt member, and a pressing member including at least a pressing roller that includes an elastic surface layer and presses the belt member against the fixed member from an outer circumferential side of the belt member in such a manner as to form a fixing part through which a recording object carrying an unfixed image is made to pass. A center, in a direction of rotation of the pressing roller, of a contact part of the fixed member that is in contact with the pressing roller through the belt member resides at a position that is displaced toward an entrance side of the fixing part with respect to a center of rotation of the pressing roller.

Abstract: A fixing device includes a heat assembly including an endless belt, a heat source, an attachment member having an attachment surface and first and second side surfaces, and a slide sheet having first and second end portions that are respectively fixed to a first fixing portion at the first side surface and a second fixing portion at the second side surface, the slide sheet having a larger length from the first end portion to the second end portion than a length of a path of the attachment member extending from the first fixing portion to the second fixing portion through the first side surface, the attachment surface, and the second side surface; and a pressure roller that presses the outer surface of the endless belt to the attachment surface.

Abstract: A fixing device includes a belt, a secured member, a support roller, a heating unit, and a pressure roller that is driven to rotate and has an elastic surface layer deformed when pressing the belt against the secured member so as to form a fixing portion. A recording medium that holds an unfixed image passes through the fixing portion. The secured member has a contact portion and an insertion portion having first and second curved surfaces respectively curved toward first and second sides opposite to each other. Conditions t(1/r1+1/r2)?0.130 and r1<r2 are satisfied where t denotes a thickness of the belt, r1 denotes a radius of curvature of the second curved surface in mm, and r2 denotes a radius of curvature of the first curved surface in mm.

Abstract: A fixing device includes: an endless belt member; a secured member disposed to contact the belt member; a support roller that rotatably supports the belt member; a heating unit that heats the belt member; and a rotary pressurizing roller that includes an elastic surface layer that is elastically deformed when the belt member is pressed against the secured member to form a fixing part. The secured member includes a recessed part provided on a surface of the secured member that faces the pressurizing roller and configured to curve the belt member into a recessed shape, projecting parts provided upstream and downstream of the recessed part, respectively, and configured to curve the belt member into a projected shape, and a region provided between at least one of the projecting parts and the recessed part and having a small curvature compared to the corresponding projecting part.

Abstract: A fixing device includes an endless belt member, a secured member disposed to contact the belt member, a heating unit that heats the belt member, and a rotary pressurizing roller including an elastic layer that is elastically deformed when the belt member is pressed against a pressing surface of the secured member to form a fixing part. The pressurizing roller is curved such that a center portion is smaller in outside diameter than end portions along the axial direction. The pressing surface is curved such that a center portion projects toward the pressurizing roller more than end portions along the longitudinal direction. On the pressing surface, an amount of projection of the center portion with respect to the end portions along the longitudinal direction is set to be larger on an output side than on an input side of the fixing part along a moving direction of the belt member.

Abstract: A fixing device includes a rotatable endless belt, a heating source that heats the belt, a pad member having a sliding surface abutting on an inner surface of the belt, and a pressure roller that presses an outer surface of the belt toward the sliding surface and rotates to rotate the belt. The pressure roller works together with the belt to fix an unfixed toner image onto a medium that bears the unfixed toner image by allowing the medium to enter between the roller and the belt. Assuming that the sliding surface is divided into upstream and downstream regions in a moving direction of the belt, the upstream and downstream regions both have recessed curved surfaces in the moving direction. A first curved surface corresponding to the upstream region has an average curvature that is larger than that of a second curved surface corresponding to the downstream region.

Abstract: A fixing device includes a heat assembly including an endless belt, a heat source, an attachment member having an attachment surface and first and second side surfaces, and a slide sheet having first and second end portions that are respectively fixed to a first fixing portion at the first side surface and a second fixing portion at the second side surface, the slide sheet having a larger length from the first end portion to the second end portion than a length of a path of the attachment member extending from the first fixing portion to the second fixing portion through the first side surface, the attachment surface, and the second side surface; and a pressure roller that presses the outer surface of the endless belt to the attachment surface.

Abstract: A fixing device includes a heat assembly including an endless belt, a heat source, an attachment member having an attachment surface and first and second side surfaces, and a slide sheet having first and second end portions that are respectively fixed to a first fixing portion at the first side surface and a second fixing portion at the second side surface, the slide sheet having a larger length from the first end portion to the second end portion than a length of a path of the attachment member extending from the first fixing portion to the second fixing portion through the first side surface, the attachment surface, and the second side surface; and a pressure roller that presses the outer surface of the endless belt to the attachment surface.

Abstract: A separation unit is provided on a downstream side of a contact area between a belt-like rotating body and a pressure rotating body. The separation unit includes a pressure member, a guide portion and a pressure portion. The pressure member extends along a width direction of the belt-like rotating body, and presses the belt-like rotating body to deform the belt-like rotating body into a bent shape changing a course away from a surface of the pressure rotating body. The guide portion is on the pressure rotating body side of the pressure member to guide the belt-like rotating body so that an angle portion of the bent shape bites into the pressure rotating body. The pressure portion is on the surface in the pressure rotating body side, and the surface separates sequentially from the pressure rotating body in the extending direction from a center portion to an end portion.

Abstract: A fixing device includes: a belt member provided to be circularly movable; a first fixing member disposed inside the belt member; a second fixing member that is disposed to be in press contact with the first fixing member across the belt member, and forms a press contact portion between the belt member and the second fixing member; a pressing member that presses the belt member against the second fixing member, the pressing member having a pressing surface that presses an inner peripheral surface of the belt member on a downstream side of the press contact portion in a moving direction of the belt member; and a suppressing unit that suppresses looseness in a portion of the belt member in the width direction thereof, the portion being located on the downstream side of the press contact portion and an upstream side of the pressing surface in the moving direction of the belt member.

Abstract: A heating device includes: a heating member heating a recording medium; a pressure member forming a heating pressure portion between the pressure member and the heating member by coming into pressure contact with the heating member, the heating pressure portion passing through the recording medium; a tensioning member placed to face the pressure member across the heating member to provide a tension to the heating member; and a cooling unit cooling the pressure member, the cooling unit including: an air blower generating an air flow; a circulator circulating the air flow along the pressure member; and a group of protruding portions provided on the circulator to guide the air flow.

Abstract: A fixing device includes: a belt member provided to be circularly movable having a width; a first fixing member disposed inside the belt member; a second fixing member disposed in press contact with the first fixing member across the belt member, and forms a passing portion with the belt member, through which a recording medium passes; and a pressing member disposed along a width direction of the belt member and downstream of the passing portion in a moving direction of the belt member, in which the pressing member has a surface and brings the surface in contact with an inner peripheral surface of the belt member to press the belt member against the second fixing member. The surface is curved toward the second fixing member along with a move from an end portion to a center portion in a longitudinal direction of the pressing member.

Abstract: A heating device includes: a heating member heating a recording medium; a pressure member forming a heating pressure portion between the pressure member and the heating member by coming into pressure contact with the heating member, the heating pressure portion passing through the recording medium; a tensioning member placed to face the pressure member across the heating member to provide a tension to the heating member; and a cooling unit cooling the pressure member, the cooling unit including: an air blower generating an air flow; a circulator circulating the air flow along the pressure member; and a group of protruding portions provided on the circulator to guide the air flow.