146results about "Roller heating devices" patented technology

The invention is to provide an image heating apparatus capable of preventing an excessive temperature increase in a sheet non-passing area and a heater for use in such apparatus, and the heater for use in the image heating apparatus of the invention is constructed by including: a substrate; a heat generating resistor formed on the substrate; and first and second electrodes for supplying an electric power to the heat generating resistor; wherein each of the first and second electrodes has a first area to be contacted with a power supplying connector and a second area provided at an end portion electrically opposite to the first area, the second areas are provided along a longitudinal direction of the substrate, and the heat generating resistor is so provided as to electrically connect the second area of the first electrode and the second area of the second electrode; wherein, within the second area of the first electrode, a portion electrically closest to the first area of the first electrode is provided in the vicinity of an end portion of the substrate in the longitudinal direction thereof, and within the second area of the second electrode, a portion electrically closest to the first area of the second electrode is provided in the vicinity of the other end portion of the substrate in the longitudinal direction thereof; and wherein, when the heater is at a set temperature for an image heating operation in the image heating apparatus, a resistance value Rc of the second area of either of the first and second electrodes and a resistance value Rt between a portion within the second area of the first electrode electrically closest to the first area of the first electrode and a portion within the second area of the second electrode electrically closest to the first area of the second electrode satisfy a relation: Rc / Rt≦1 / 30.

The heater is capable of improving heat generation uniformity in a sheet feeding area while suppressing the temperature rise of a non-sheet feeding portion. Each of heat generation lines includes a plurality of heat blocks in which a plurality of heat generating resistors are electrically connected in parallel between two conductive members. The heat generation lines are arranged in a lateral direction of the substrate, and the heat blocks are arranged so that the end of the heat block in the heat generation line of a first row does not overlap with the end of the heat block in the heat generation line of a second row in a longitudinal direction of a heater.

Provided is a heating resistor element including: an insulating substrate including a glass material; a heat accumulating layer bonded to the insulating substrate through heating to temperature ranging from an annealing point to a softening point in a state of being adhered to a surface of the insulating substrate, and including the same material as the glass material of the insulating substrate; and a heating resistor provided on the heat accumulating layer, in which, on at least one of bonded surfaces between the insulating substrate and the heat accumulating layer, at least one of the insulating substrate and the heat accumulating layer is provided with a concave portion in a region opposed to the heating resistor to form a hollow portion. Accordingly, deformation caused by a difference in coefficient of thermal expansion is suppressed to improve printing quality.