In one example in accordance with the present disclosure, a method for determining fusing energy per page based on an applied voltage is described. According to the method, a resistance of a fusing system is acquired and an input voltage of a fusing system is estimated. A duty ratio of the fusing system is measured and a fusing energy per processed page is then determined based on the input voltage, the fusing system resistance, and the duty ratio of the fusing system. A media weight is then determined based on the fusing energy per processed page.

According to one embodiment, a fixing device includes determination means for determining the size of an image forming area of a medium, heating means for including an endless rotating body, plural heat-generating members which are formed in a perpendicular direction to a transporting direction, inclined by a predetermined angle, and divided by a predetermined length, and are disposed so as to come into contact with an inner side of the rotating body, and a switching unit which switches individual conduction, and heats the medium, pressing means for forming a nip by performing pressing and contact at a position of the plural heat-generating members, and nipping and carrying the medium in the transporting direction along with the heating means, and heating control means for controlling the switching unit to select and conduct heat-generating members and controlling the heating means to heat the medium.

An image heating apparatus has a heater to heat an image formed on a recording material. The heater has a plurality of heat generating elements. A control portion controls electrical power supplied to the plurality of heat generating elements. The control portion respectively sets a heating amount with respect to a region in which an image is formed and a heating amount with respect to a region in which an image is not formed in a single sheet of the recording material. The control portion is further configured to at least set the heating amount with respect to the region in which the image is not formed when the recording material is heavy paper to become less than the heating amount with respect to the region in which the image is not formed when the recording material is plain paper.

A fixing apparatus includes a plurality of heat generating elements for heating a developer image formed on a recording medium corresponding to a plurality of heating regions. A first target temperature of the heat generating elements is set based on a developer amount per unit area of the developer image in each of the heating regions, and the temperature of the heat generating elements is controlled to the first target temperature. If a difference between the first target temperatures for two adjacent heating regions is outside of a predetermined range, the first target temperature for one of the two adjacent heating regions is corrected to a second target temperature, which is greater than the first target temperature, so that the difference between the first target temperatures for the two adjacent heating regions is within the predetermined range.

A fixing device includes a rotating unit, a heating unit configured to heat the rotating unit, and a pressure member configured to nip a recording material between the rotating unit and the pressure member and to convey the recording material. A control portion is configured to change the rotating unit from a rotating state to a halt state. A setting portion is configured to set a heating temperature of the heating unit in the rotating state according to information of a basis weight of the recording material. In addition, a determining portion is configured to determine whether or not a heating operation of the heating unit in the halt state is to be performed according to the information of the basis weight of the recording material.

A heating device includes an elongated heater, a first holding member configured to hold the heater, a power shut-off member configured to shut off power supply to the heater, a second holding member configured to hold the power shut-off member, a first urging member configured to press the power shut-off member against the heater, and a regulation member configured to regulate a position of the second holding member, wherein, in a longitudinal direction of the heater, one end side of the second holding member is urged by the first urging member, and another end side of the second holding member is regulated in position by the regulation member.

A printing apparatus includes a first determining unit configured to determine a conveyance profile corresponding to a print mode, a conveying unit configured to convey a printing medium on which on an image is printed, according to the conveyance profile, a fixing unit configured to fix the image onto the printing medium by heating the printing medium, a measuring unit configured to measure each of a length of the printing medium before heating in the fixing unit and a length of the printing medium after the heating by detecting the image on the printing medium conveyed according to the conveyance profile, a deriving unit configured to derive a characteristic of a deformation amount of the printing medium with respect to temperature based on the measured lengths, and a second determining unit configured to determine a fixation temperature to be used for the printing medium based on the derived characteristic.

A printing apparatus includes a fixing unit configured to fix an image onto a printing medium by heating the printing medium on which the image is printed, a measuring unit configured to measure a length of the printing medium after heating of the printing medium in the fixing unit, a deriving unit configured to derive a characteristic of a deformation amount of the printing medium with respect to temperature based on the measured length, a receiving unit configured to receive a specification of a deformation amount threshold, and a determining unit configured to determine a fixation temperature in fixation of the image onto the printing medium by the fixing unit, based on the derived characteristic and the received deformation amount threshold.

A fixing device includes an elastic roller and a back-up unit cooperative with the elastic roller to form a fixing nip therebetween, the back-up unit including a cylindrical film contacting the elastic roller, and a heat leveling member contacting an inner surface of the film to cooperate with the elastic roller to form a nip nipping the film. An unfixed toner image is heat-fixed on a recording material at the fixing nip while feeding the recording material carrying the unfixed toner image at the fixing nip. The apparatus feeds the recording material such that the unfixed toner image contacts the elastic roller. The film includes a layer of thermoplastic resin material, and, when the device fixes the unfixed toner image on a small size sheet, a temperature of a non-sheet-passage-part of the film rises to a temperature that is greater than a glass transition point of the thermoplastic resin material.

According to one embodiment, a fixing device includes a heat roller, a first heat generating body, a second heat generating body, and a power adjuster. The heat roller heats a conveyed sheet. The first heat generating body is provided in the heat roller and generates heat in the vicinity of the center in the length direction of the heat roller. The second heat generating body is provided in the heat roller and generates heat in the vicinities of both the ends in the length direction of the heat roller. The power adjuster applies thinning control to electric energy supplied to one or both of the first heat generating body and the second heat generating body.