Abstract: A fixing device includes a fixing belt, a pressure rotating body, a nip member, a heating member, a rotating member and a biasing member. The fixing belt is arranged rotatably around a rotating axis. The pressure rotating body is rotatably arranged at an external diameter side of the fixing belt to come into pressure contact with the fixing belt and to form a fixing nip. The nip member is arranged at an internal diameter side of the fixing belt to press the fixing belt toward a side of the pressure rotating body. The heating member comes into contact with a contacted area in an inner circumference face of the fixing belt to heat the fixing belt. The rotating member sandwiches an end part of the fixing belt with the heating member and is rotated together with the fixing belt. The biasing member presses the heating member to the contacted area.

Abstract: A fixing device includes a fixing belt, a pressuring member, a pressing member, a heat source and a heat transmitting member. The fixing belt is arranged rotatably. The pressuring member is arranged rotatably to come into pressure contact with the fixing belt so as to form a fixing nip. The pressing member presses the fixing belt to a side of the pressuring member. The heat source is arranged at the inside in a radial direction of the fixing belt to radiate a radiant heat. The heat transmitting member comes into contact with an inner circumference face of the fixing belt to absorb the radiant heat radiated from the heat source. A part of the heat transmitting member is sandwiched between the fixing belt and the pressing member.

Abstract: A fixing device includes a fixing belt, a pressuring member, a heat source and a nip member. The fixing belt is arranged rotatably. The pressuring member is arranged rotatably to come into pressure contact with the fixing belt so as to form a fixing nip. The heat source is arranged at the inside in a radial direction of the fixing belt to radiate a radiant heat. The nip member is arranged so as to sandwich the fixing belt between the nip member and the pressuring member. The heat source, the fixing belt and the nip member are arranged so that the radiant heat radiated from the heat source reaches directly an inner circumference face of the fixing belt and the nip member.

Abstract: A developing device includes a storing portion, a stirring member, a developing roller, a shield plate, and a guide portion. The storing portion stores developer. The stirring member is rotatably provided in the storing portion and stirs the developer in the storing portion by being rotationally driven in a predetermined first rotation direction. The developing roller is rotatably provided above the stirring member, has a magnet that attracts the developer in the storing portion by a magnetic force, and is rotationally driven in a predetermined second rotation direction. The shield plate is made of a nonmagnetic material and provided at a facing position where the developing roller and the stirring member face each other. The guide portion is provided more on an upstream side in the first rotation direction than the facing position, and guides the developer from the storing portion to the developing roller side.

Abstract: A fixing device includes a fixing belt, a pressuring member, a heat source and a nip member. The fixing belt is arranged rotatably. The pressuring member is arranged rotatably to come into pressure contact with the fixing belt so as to form a fixing nip. The heat source is arranged at the inside in a radial direction of the fixing belt to radiate a radiant heat. The nip member is arranged so as to sandwich the fixing belt between the nip member and the pressuring member. The heat source, the fixing belt and the nip member are arranged so that the radiant heat radiated from the heat source reaches directly an inner circumference face of the fixing belt and the nip member.

Abstract: A fixing device includes a fixing belt, a pressuring member, a pressing member, a heat source and a heat transmitting member. The fixing belt is arranged rotatably. The pressuring member is arranged rotatably to come into pressure contact with the fixing belt so as to form a fixing nip. The pressing member presses the fixing belt to a side of the pressuring member. The heat source is arranged at the inside in a radial direction of the fixing belt to radiate a radiant heat. The heat transmitting member comes into contact with an inner circumference face of the fixing belt to absorb the radiant heat radiated from the heat source. A part of the heat transmitting member is sandwiched between the fixing belt and the pressing member.

Abstract: A fixing device includes a fixing belt, a pressure rotating body, a nip member, a supporting member, a heating source, a heat conducting member and a reflecting member. The pressure rotating body is rotatably arranged outside the fixing belt to come into pressure contact with the fixing belt to form a fixing nip. The nip member is arranged inside the fixing belt to press the fixing belt toward the pressure rotating body. The supporting member supports the nip member. The heating source is arranged inside the fixing belt to emit radiant heat. The heat conducting member is supported by the supporting member in a cantilevered state to come into contact with an inner circumference face of the fixing belt and to absorb the radiant heat. The reflecting member reflects the radiant heat toward the heat conducting member and at least partially comes into contact with the heat conducting member.

Abstract: A developing device includes a storing portion, a stirring member, a developing roller, a shield plate, and a guide portion. The storing portion stores developer. The stirring member is rotatably provided in the storing portion and stirs the developer in the storing portion by being rotationally driven in a predetermined first rotation direction. The developing roller is rotatably provided above the stirring member, has a magnet that attracts the developer in the storing portion by a magnetic force, and is rotationally driven in a predetermined second rotation direction. The shield plate is made of a nonmagnetic material and provided at a facing position where the developing roller and the stirring member face each other. The guide portion is provided more on an upstream side in the first rotation direction than the facing position, and guides the developer from the storing portion to the developing roller side.

Abstract: A fixing device includes a fixing belt, a pressure rotating body, a nip member, a heating member, a rotating member and a biasing member. The fixing belt is arranged rotatably around a rotating axis. The pressure rotating body is rotatably arranged at an external diameter side of the fixing belt to come into pressure contact with the fixing belt and to form a fixing nip. The nip member is arranged at an internal diameter side of the fixing belt to press the fixing belt toward a side of the pressure rotating body. The heating member comes into contact with a contacted area in an inner circumference face of the fixing belt to heat the fixing belt. The rotating member sandwiches an end part of the fixing belt with the heating member and is rotated together with the fixing belt. The biasing member presses the heating member to the contacted area.

Abstract: A fixing device includes a fixing belt, a pressure rotating body, a nip member, a supporting member, a heating source, a heat conducting member and a reflecting member. The pressure rotating body is rotatably arranged outside the fixing belt to come into pressure contact with the fixing belt to form a fixing nip. The nip member is arranged inside the fixing belt to press the fixing belt toward the pressure rotating body. The supporting member supports the nip member. The heating source is arranged inside the fixing belt to emit radiant heat. The heat conducting member is supported by the supporting member in a cantilevered state to come into contact with an inner circumference face of the fixing belt and to absorb the radiant heat. The reflecting member reflects the radiant heat toward the heat conducting member and at least partially comes into contact with the heat conducting member.

Abstract: A fixing unit includes a heating rotor, a pressure rotor, an induction coil, and a magnetic core portion having a bypass core portion and a magnetic flux shielding member. The induction coil generates a magnetic flux to heat the heating rotor. A Curie point of the bypass core portion is higher than the temperature of the bypass core portion when the temperature of the heating rotor has reached a fixing temperature for fixing of the transfer material, and lower than the temperature of the bypass core portion when the temperature of the heating rotor has reached a heat-resistant temperature. The magnetic flux shielding member is configured about the periphery of the bypass core portion in close proximity or abutment with the bypass core portion.

Abstract: A fixing unit includes a heating rotor, a pressure rotor, an induction coil, and a magnetic core portion having a bypass core portion and a magnetic flux shielding member. The induction coil generates a magnetic flux to heat the heating rotor. A Curie point of the bypass core portion is higher than the temperature of the bypass core portion when the temperature of the heating rotor has reached a fixing temperature for fixing of the transfer material, and lower than the temperature of the bypass core portion when the temperature of the heating rotor has reached a heat-resistant temperature. The magnetic flux shielding member is configured about the periphery of the bypass core portion in close proximity or abutment with the bypass core portion.

Abstract: A fixing device for fixing a toner image to a sheet and has a fixing roller to be heated by a heat source and a pressure roller to be pressed into contact with the fixing roller. A switcher switches a pressing force between the fixing roller and the pressure roller between a first pressing force and a second pressing force lower than the first pressing force. A pressing force detector detects the pressing force between the fixing roller and the pressure roller and a temperature detector detects the temperature of the fixing roller. A storage device stores control data indicating a control temperature for the fixing roller predetermined in accordance with the number of sheets passing the fixing device, and a controller controls the temperature of the fixing roller to the control temperature by controlling the heat source in accordance with a signal sent from the pressing force detector.

Abstract: A fixing device has a heating roller with a heat source therein. A power supply operates the heat source for heating a transfer material and fixing a toner image thereon. A pressure roller is spaced from the heating roller and a facing member faces the heating roller. An endless fixing belt is mounted on the facing member and the heating roller and contacts the pressure roller to form a nip. A temperature detector faces the outer surface of the fixing belt for detecting the surface temperature thereof. An excessive temperature preventer faces part of the outer surface of the heating roller where the fixing belt is not mounted for detecting the surface temperature of the heating roller and cutting off the power supply to the heat source when the surface temperature rises above a preset temperature.

Abstract: A fixing device for fixing a toner image to a sheet and has a fixing roller to be heated by a heat source and a pressure roller to be pressed into contact with the fixing roller. A switcher switches a pressing force between the fixing roller and the pressure roller between a first pressing force and a second pressing force lower than the first pressing force. A pressing force detector detects the pressing force between the fixing roller and the pressure roller and a temperature detector detects the temperature of the fixing roller. A storage device stores control data indicating a control temperature for the fixing roller predetermined in accordance with the number of sheets passing the fixing device, and a controller controls the temperature of the fixing roller to the control temperature by controlling the heat source in accordance with a signal sent from the pressing force detector.

Abstract: A fixing device has a heating roller with a heat source therein. A power supply operates the heat source for heating a transfer material and fixing a toner image thereon. A pressure roller is spaced from the heating roller and a facing member faces the heating roller. An endless fixing belt is mounted on the facing member and the heating roller and contacts the pressure roller to form a nip. A temperature detector faces the outer surface of the fixing belt for detecting the surface temperature thereof. An excessive temperature preventer faces part of the outer surface of the heating roller where the fixing belt is not mounted for detecting the surface temperature of the heating roller and cutting off the power supply to the heat source when the surface temperature rises above a preset temperature.

Abstract: An image forming apparatus includes a fusing device comprising of a fuser roller, which fuses toner on a sheet of paper, and a pressure roller getting into contact with the fuser roller to form a nip between them where the sheet of paper passes through. A fuser-side external heat roller having an internal heater comes into contact with the fuser roller. A pressure-side heat roller having an internal heater comes into contact with the pressure roller. The fuser roller and the pressure roller have approximately same outer diameter and are both composed of an elastic material. An approximate radius of the nip formed between the two rollers is set to be equal to or larger than a radius of the fuser roller or the pressure roller. In another construction, the rollers are different in outer diameter, but each composed of an elastic material and a nip between them is set to be equal to or larger than 1.25 times as large as the radius of either the fuser roller or the pressure roller with smaller outer diameter.

Abstract: Disclosed is an image formation method using electrophotography, comprising the steps of supplying a developer by a developing device (17) onto a photosensitive drum (11) in rotation to form a toner image thereon, transferring the formed toner image onto a transfer paper to form an image on the transfer paper, and removing untransferred developer by use of a cleaning blade (21), wherein an OPC photosensitive drum (11) is used for the photosensitive drum and includes a photosensitive layer (27) being formed on an electrically conductive base (25) and having an initial thickness which is a value within a range of 20 to 50 &mgr;m, and wherein the amount X of reduction in the thickness of the photosensitive layer (27) in the OPC photosensitive drum (11) satisfies the following expression (1) 0.5 &mgr;m<30X/R<1.