Abstract: An image heating device includes a fixing belt (100) including a heat generating layer (102); a pressure roller (110) configured to rotationally drive the fixing belt; a power feed ring (119) disposed at one end of the fixing belt in a longitudinal direction and extending along an outer periphery of the fixing belt, the power feed ring being electrically connected to the heat generating layer; a brush (81) configured to be brought into contact with an outer periphery of the power feed ring and electrically connected to the power feed ring; a power supply circuit (79) configured to feed power to the brush; and a leaf spring (82) configured to elastically press the brush toward the power feed ring, the leaf spring being configured to come into contact with the power feed ring when the brush wears by a predetermined amount.

Abstract: A calculating device for calculating a lifetime of a rotatable member for heating a toner image on a recording material at a nip includes a first acquiring portion configured to acquire a rotation time of the rotatable member; an accumulating portion configured to accumulate the rotation time of the rotatable member acquired by the first acquiring portion; and a second acquiring portion configured to acquire a temperature of the rotatable member. The accumulating portion accumulates the rotation time of the rotatable member acquired by the first acquiring portion after weighting is made on the basis of the temperature of the rotatable member acquired by the second acquiring portion.

Abstract: A heater includes a substrate, a first electrical contact, second electrical contacts, first electrode portions and second electrode portions, heat generating portions, a first electroconductive line portion, and a second electroconductive line portion. The heat generating portions are disposed so as to be offset from a center line of the substrate with respect to a widthwise direction of the substrate.

Abstract: A heater includes a substrate, a first electrical contact, a plurality of second electrical contacts, a plurality of electrode portions including first electrode portions electrically connected with the first electrical contact and second electrode portions electrically connected with the second electrical contacts, the first electrode portions and the second electrode portions being arranged alternately with predetermined gaps in a longitudinal direction of the substrate, and a plurality of heat generating portions provided between adjacent ones of the electrode portions so as to electrically connect between adjacent electrode portion. The heat generating portions are capable of generating heat by the electric power supply between adjacent electrode portions. A part of the second electrical contacts is selectably electrically connectable with the second terminal. The electrode portions are covered with the heat generating portions so as to be positioned between the substrate and the heat generating portions.

Abstract: A heater includes: a substrate; a first electrical contact; second electrical contacts; first and second electrodes; heat generating portions; a first electroconductive line portion electrically connecting the first electrical contact and the first electrode portions; and a second electroconductive line portion electrically connecting one of the second electrical contacts and a part of the second electrode portions. A cross-sectional area of a portion, of the first electroconductive line portion, into which all of currents flowing through the first electrode portions merge when the currents flow from the first electrode portions toward the first electrical contact is larger than a cross-sectional area of a portion, of the second electroconductive line portion, into which all of currents flowing through the part of the second electrode portions merge when the currents flow from the part of the second electrode portions toward the one of second electrical contacts.

Abstract: A heater includes: a substrate; a first electrical contact; a plurality of second electrical contacts; an electroconductive line portion electrically connected with the first electrical contact; a plurality of electrode portions including first electrode portions electrically connected with the first electrical contact through the electroconductive line portion and second electrode portions electrically connected with the second electrical contacts; and a plurality of heat generating portions provided between adjacent ones of the electrode portions. The cross-section of the electroconductive line portion in a side closer to the first electrical contact than the plurality of heat generating portions with respect to the longitudinal direction is larger than the cross-section of a predetermined electrode portion, between adjacent heat generating portions, of the plurality of electrode portions.

Abstract: A heater includes a substrate, a first electrical contact, second electrical contacts, first electrode portions and second electrode portions, heat generating portions, a first electroconductive line portion, and a second electroconductive line portion. The heat generating portions are disposed so as to be offset from a center line of the substrate with respect to a widthwise direction of the substrate.

Abstract: An image heating apparatus includes a heating belt having a heat generating layer configured to generate heat by energization, a pressing roller configured to abut on an outer peripheral surface of the heating belt to form a nip portion, a pressing mechanism configured to press the heating belt against the pressing roller, an outer ring electrically connected to the heating belt in an end portion of the heating belt, a power feed member configured to abut on the outer ring to feed power to the outer ring, and an inner ring configured to clamp the end portion of the heating belt between the inner ring and the outer ring. A chamfered portion of the inner ring is chamfered.

Abstract: A heater includes a substrate, electrode portions, electrical contact portions, heat generating portions, and electroconductive line portions. The electrode portions include first group electrode portions and second group electrode portions. The electroconductive line portions include a main line portion extending from the electrical contact portions in the longitudinal direction, a first branch line portion branching from the main line portion so as to electrically connect with a first electrode portion of the first group electrode portions, and a second branch line portion branching from the main line portion so as to electrically connect with a second electrode portion of the first group electrode portions. The second electrode portion is spaced farther from the electrical contact portions than the first electrode portion in the longitudinal direction, and the electric resistance of the first branch line portion is larger than the electric resistance of the second branch line portion.

Abstract: A fixing device includes a rotatable heating member and a rotatable pressing member which are configured to fix a toner image on a recording material in a nip therebetween; and a heating mechanism configured to selectively heat regions of the rotatable heating member depending on sizes of the recording material when the sizes are predetermined ones of all sizes usable in the fixing device. The rotatable pressing member includes a base layer and a porous elastic layer provided on the base layer and containing a needle-like filler. The elastic layer having a thermal conductivity, with respect to a longitudinal direction thereof, which is 6 times to 900 times a thermal conductivity with respect to a thickness direction thereof.

Abstract: A fixing apparatus including a flexible belt having a heat generating layer, an outer ring provided on one edge side of the belt and along an outer peripheral surface of the belt, the outer ring being electrically connected to the heat generating layer, an inner ring provided on the one edge side of the belt and along an inner peripheral surface of the belt to face the outer ring through the belt, and a power supply unit that is electrically connected to the outer ring and that feeds power. A difference obtained by subtracting a diameter of the inner ring at a normal temperature from a diameter of the inner ring at a fixing temperature is equivalent to or larger than a difference obtained by subtracting a diameter of the outer ring at the normal temperature from a diameter of the outer ring at the fixing temperature.

Abstract: An image heating apparatus includes a heating belt having a heat generating layer configured to generate heat by energization, a pressing roller configured to abut on an outer peripheral surface of the heating belt to form a nip portion, a pressing mechanism configured to press the heating belt against the pressing roller, an outer ring electrically connected to the heating belt in an end portion of the heating belt, a power feed member configured to abut on the outer ring to feed power to the outer ring, and an inner ring configured to clamp the end portion of the heating belt between the inner ring and the outer ring. A chamfered portion of the inner ring is chamfered.

Abstract: A heater includes a substrate, electrode portions, electrical contact portions, heat generating portions, and electroconductive line portions. The electrode portions include first group electrode portions and second group electrode portions. The electroconductive line portions include a main line portion extending from the electrical contact portions in the longitudinal direction, a first branch line portion branching from the main line portion so as to electrically connect with a first electrode portion of the first group electrode portions, and a second branch line portion branching from the main line portion so as to electrically connect with a second electrode portion of the first group electrode portions. The second electrode portion is spaced from the electrical contact portions more than the first electrode portion in the longitudinal direction, and an electric resistance of the first branch line portion is larger than an electric resistance of the second branch line portion.

Abstract: A heater includes a substrate, a first electrical contact, a plurality of second electrical contacts, a plurality of electrode portions including first electrode portions electrically connected with the first electrical contact and second electrode portions electrically connected with the second electrical contacts, the first electrode portions and the second electrode portions being arranged alternately with predetermined gaps in a longitudinal direction of the substrate, and a plurality of heat generating portions provided between adjacent ones of the electrode portions so as to electrically connect between adjacent electrode portions, the heat generating portions being capable of generating heat by the electric power supply between adjacent electrode portions. A part of the second electrical contacts is selectably electrically connectable with the second terminal.

Abstract: A heater includes: a substrate; a first electrical contact; second electrical contacts; first electrode portions and second electrode portions; heat generating portions; a first electroconductive line portion electrically connecting the first electrical contact and the first electrode portions; and a second electroconductive line portion electrically connecting one of the second electrical contacts and a part of the second electrode portions. A cross-sectional area of a portion, of the first electroconductive line portion, into which all of currents flowing through the first electrode portions merge when the currents flow from the first electrode portions toward the first electrical contact is larger than a cross-sectional area of a portion, of the second electroconductive line portion, into which all of currents flowing through the part of the second electrode portions merge when the currents flow from the part of the second electrode portions toward the one of second electrical contacts.

Abstract: A heater includes a substrate; a first electrical contact a plurality of second electrical contacts an electroconductive line portion electrically connected with the first electrical contact; a plurality of electrode portions including first electrode portions electrically connected with the first electrical contact through the electroconductive line portion and second electrode portions electrically connected with the second electrical contacts; and a plurality of heat generating portions provided between adjacent ones of the electrode portions. A cross-section of the electroconductive line portion in a side closer to the first electrical contact than the plurality of heat generating portions are with respect to the longitudinal direction is larger than a cross-section of a predetermined electrode portion, between adjacent heat generating portions, of the plurality of electrode portions.

Abstract: A fixing device includes a rotatable heating member and a rotatable pressing member which are configured to fix a toner image on a recording material in a nip therebetween; and a heating mechanism configured to selectively heat regions of the rotatable heating member depending on sizes of the recording material when the sizes are predetermined ones of all sizes usable in the fixing device. The rotatable pressing member includes a base layer and a porous elastic layer provided on the base layer and containing a needle-like filler. The elastic layer having a thermal conductivity, with respect to a longitudinal direction thereof, which is 6 times to 900 times a thermal conductivity with respect to a thickness direction thereof.

Abstract: An image heating apparatus includes an endless belt configured to heat an image on a sheet at a nip potion, a heat generation device configured to cause the belt to generate heat, a nip forming member configured to form the nip portion between the nip forming member and the belt, and a pressing roller configured to press an inner surface of the belt toward the nip forming member, the pressing roller including an elastic porous layer containing a plurality of filler particles, wherein a thermal conductivity of the elastic porous layer in an axial direction of the pressing roller is in a range of 6 times to 900 times a thermal conductivity of the elastic porous layer in a radial direction of the pressing roller.

Abstract: An image heating apparatus includes an endless belt configured to heat an image on a sheet at a nip potion, a heat generation device configured to cause the belt to generate heat, a nip forming member configured to form the nip portion between the nip forming member and the belt, and a pressing roller configured to press an inner surface of the belt toward the nip forming member, the pressing roller including an elastic porous layer containing a plurality of filler particles, wherein a thermal conductivity of the elastic porous layer in an axial direction of the pressing roller is in a range of 6 times to 900 times a thermal conductivity of the elastic porous layer in a radial direction of the pressing roller.

Abstract: An image forming portion of an image forming apparatus is configured to form a toner image on a recording medium such that a relationship of M???L/(30?3) is satisfied, where a volume average particle size of toner is L (?m), density of the toners is ? (g/cm3), and a maximum toner laid quantity per unit area of a single color toner image on a recording medium is M (mg/cm2). The toner image formed by the image forming portion is fixed on the recording medium by a fixing nip portion by being heated and applied a force in a direction of a plane of the recording medium.