Abstract: A fixing device is disclosed, including: a fixing rotative body, a heat source, and a control part. The control part conducts a printing temperature control which varies an ON ratio per unit time of the heat source based on a detection result of the temperature detecting part to maintain a printing target temperature in a printing state, conducts a waiting temperature control which performs an ON/OFF control based on the detection result of the temperature detecting part to maintain a waiting target temperature in a waiting state after a printing operation ends, and conducts a forcible ON control which forcibly turns on the heat source for a predetermined time before starting the ON/OFF control when the detection result of the temperature detecting part after the printing operation ends is lower than the waiting target temperature.

Abstract: The fixing device includes a fixing unit, a pressure unit that comes into pressure-contact with the fixing unit to form a nip, and control guides. The fixing unit includes a heat roller. The pressure unit includes a pressure belt, and a pressure pad. The pressure pad is attached to a holder and pressed by a spring through a stay, thereby bringing the pressure belt into pressure-contact with the heat roller. The control guides on both sides of the pressure pad control deformation of the pressure pad in an axial direction of the heat roller to make a nip shape uniform.

Abstract: A pressurizing member includes an elastic member having a uniform elastic modulus of K=EA/t, where E is a Young's modulus, A is an area of the nip portion, and t is a thickness of the elastic member in the direction of application of load. A supporting member that supports the pressurizing member has an entering portion, an exit portion, and a center portion between the entering portion and the exit portion. The thickness of the center portion in a direction of application of load is larger than thicknesses of the entering portion and the exit portion in the direction of application of load so that the supporting unit has a convex portion.

Abstract: A pressurizing unit includes a contact-pressure member for pressurizing an endless belt, a holding member that holds the contact-pressure member, and a biasing member that presses both ends of the holding member. The biasing member presses the holding member, so that a direction in which the biasing member presses the holding member is substantially the same as a direction in which the holding member presses the pressure-contact member.

Abstract: A ratio of a radius of curvature of a pressure applying member with an elastic layer, which pushes an endless belt wound around an endless heating member with pressure, in a transferring direction to a radius of curvature of an outer diameter of the heating roller is set to 1.1 or more.

Abstract: In a fixing apparatus, an internal temperature detection device is arranged within a heat generation region and detects temperature of a fixing device. An external temperature detection device is arranged at the outside of the heat generation region and detects temperature of the fixing device. Heat generation in the heat generating device is stopped when temperature reaches a prescribed first high temperature detection limit and a temperature rising amount in a prescribed time period after the first high temperature detection limit is reached exceeds a prescribed threshold.

Abstract: A fixing device includes a rotary fixing member, a counter member to contact the rotary fixing member, a first heater to heat the rotary fixing member, a driving unit to rotate the rotary fixing member, a temperature detector to detect a temperature of the rotary fixing member, and a contact-and-separation unit to switch between contact and separation states of the rotary fixing member relative to the counter member. In a temperature-raising operation, the driving unit causes the rotary fixing member to rotate when the temperature detector detects that the temperature of the rotary fixing member has reached a first setting temperature. The contact-and-separation unit causes the rotary fixing member in rotation and the counter member to contact each other when the temperature detector detects that the temperature of the rotary fixing member has reached a second setting temperature that is higher than the first setting temperature.

Abstract: A temperature control method for use in a fixing device that fixes a toner image on a recording sheet by passing the recording sheet through a fixing nip defined between a fixing member and a pressure member includes temperature detection, heater control, and duty control execution. The temperature detection detects a temperature of the fixing member with a temperature detector. The heater control controls operation of a heater of the fixing device by changing a duty thereof according to the detected temperature. The duty control execution executes a heater duty control to change a heater duty for a current control cycle discontinuously from that for a previous control cycle when the current control cycle precedes entry of the recording sheet into the fixing nip by a given period of time.

Abstract: An image forming apparatus, such as a printer, includes an image forming unit forming a toner image on an image carrier, a transfer unit for transferring the toner image onto a recording medium, a pair of a fusing rotating body and a pressure rotating body, a fusing unit for fusing the toner image on the recording medium, a temperature detecting unit for detecting the temperature on the surface of the fusing rotating body, and a control unit. An amount of decrease in the temperature of the fusing rotating body surface is measured at a predetermined time, and the time between an image formation request and the arrival of the recording medium, with the toner image formed thereon, at a fusing/nipping portion formed between the fusing rotating body and the pressure rotating body is extended when the temperature decrease amount is greater than a threshold value.

Abstract: To accomplish high-speed fixing which requires high-precision temperature control, or fixing of high-quality color images on various kinds of paper without increasing the size and production cost of the temperature detecting means and contaminating the back sides of paper by toner that comes off from the temperature detecting element, an image forming device is equipped with a fixing device comprising a heating roller, a pressing belt which forcibly contacts the heating roller, and a temperature detecting means which touches the surface of the heating roller to sense the surface temperature of the heating roller, wherein a cleaning means to clean the belt surface is provided on a place which is corresponding to a place at which the contact-type thermistor touches the heating roller.

Abstract: In a fixing apparatus including heating member having an elastic layer and a heat source and pressing member having an endless shape member and a pressing member for transporting a record medium in a cut sheet shape while being adhered with an unfixed toner image to pass a nip portion formed by the endless shape member and the heating member and fixing the unfixed toner image on the record medium, the fixing apparatus is constructed by a constitution in which a space between the toner image on the record medium and a surface of the heating member is widened immediately after the record medium is projected from an outlet of the nip portion.

Abstract: A disclosed fixing device includes: a heat roller unit having a rotatable roller having an elastic body on a surface thereof and a heating unit heating the roller; a pad disposed along a circumference of the elastic body of the heat roller; a belt member disposed on a curved surface of the pad, the belt member rotating by following a rotation of the heat roller; and a pressure member pressing the belt member to the heat roller using the pad, the fixing device causing a conveyed recording medium carrying a visualized image to pass through a space between the heat roller and the pressure member so as to fix the visualized image on the recording medium, wherein a curvature of the curved surface of the pad is changed in a central portion and end portions in an axial direction of the heat roller.

Abstract: The fixing device includes a fixing unit, a pressure unit that comes into pressure-contact with the fixing unit to form a nip, and control guides. The fixing unit includes a heat roller. The pressure unit includes a pressure belt, and a pressure pad. The pressure pad is attached to a holder and pressed by a spring through a stay, thereby bringing the pressure belt into pressure-contact with the heat roller. The control guides on both sides of the pressure pad control deformation of the pressure pad in an axial direction of the heat roller to make a nip shape uniform.

Abstract: A pressurizing unit includes a contact-pressure member for pressurizing an endless belt, a holding member that holds the contact-pressure member, and a biasing member that presses both ends of the holding member. The biasing member presses the holding member, so that a direction in which the biasing member presses the holding member is substantially the same as a direction in which the holding member presses the pressure-contact member.

Abstract: A pressurizing member includes an elastic member having a uniform elastic modulus of K=EA/t, where E is a Young's modulus, A is an area of the nip portion, and t is a thickness of the elastic member in the direction of application of load. A supporting member that supports the pressurizing member has an entering portion, an exit portion, and a center portion between the entering portion and the exit portion. The thickness of the center portion in a direction of application of load is larger than thicknesses of the entering portion and the exit portion in the direction of application of load so that the supporting unit has a convex portion.

Abstract: A fixing device includes a first fixing part having a heater disposed therein, a second fixing part, disposed to oppose to the first fixing part, for pinching a recording medium to form a first nip portion, a pair of transfer rollers, disposed at a downstream side of the recording medium, for forming a second nip portion, a guide for biasing the recording medium discharged from the transfer rollers towards the first fixing part side from one of the transfers rollers, and means part for biasing the guide towards the recording medium side.

Abstract: A disclosed fixing device includes: a heat roller unit having a rotatable roller having an elastic body on a surface thereof and a heating unit heating the roller; a pad disposed along a circumference of the elastic body of the heat roller; a belt member disposed on a curved surface of the pad, the belt member rotating by following a rotation of the heat roller; and a pressure member pressing the belt member to the heat roller using the pad, the fixing device causing a conveyed recording medium carrying a visualized image to pass through a space between the heat roller and the pressure member so as to fix the visualized image on the recording medium, wherein a curvature of the curved surface of the pad is changed in a central portion and end portions in an axial direction of the heat roller.

Abstract: An image formation apparatus is disclosed. The image formation apparatus includes a fixing unit whose heater temperature is controlled to be in a non-offsetting range so that no offset is produced, the non-offsetting range being defined for each different paper thickness. Nip time remains constant even when the thickness of the paper to be printed on next is changed. Printing is suspended until the heater temperature, approaching the non-offsetting range, reaches an inconspicuous offset range on either side of the non-offsetting range, inconspicuous offset being produced if printing is performed in the inconspicuous offset range.

Abstract: In a fixing apparatus including heating member having an elastic layer and a heat source and pressing member having an endless shape member and a pressing member for transporting a record medium in a cut sheet shape while being adhered with an unfixed toner image to pass a nip portion formed by the endless shape member and the heating member and fixing the unfixed toner image on the record medium, the fixing apparatus is constructed by a constitution in which a space between the toner image on the record medium and a surface of the heating member is widened immediately after the record medium is projected from an outlet of the nip portion.

Abstract: A ratio of a radius of curvature of a pressure applying member with an elastic layer, which pushes an endless belt wound around an endless heating member with pressure, in a transferring direction to a radius of curvature of an outer diameter of the heating roller is set to 1.1 or more.