According to one embodiment, a fixing device includes determination means for determining the size of a medium, heating means for including plural heat-generating members which are two-dimensionally arranged such that the heat-generating members are lined up along two parallel lines or more which are vertical to a transport direction of the medium and divided at locations on the parallel lines, 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 heating control means for selecting a group of the heat-generating members which are lined up in the two-dimensional arrangement, conducting the selected group of the heat-generating members, and controlling the heating means.

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.

A fuser device is provided with a first endless belt, a heat application member that is enclosed by the first endless belt and heats the first endless belt, a fuser member enclosed by the first endless belt, a second endless belt of which rigidity is higher than that of the first endless belt, a pressure application member that is enclosed by the second endless belt and applies a pressure to developers on a carried recording medium in the contact part with the fuser member, and a support part forming part that forms a support part of the first endless belt and the second endless belt.

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.

According to one embodiment, a fixing device includes determination means for determining the size of a medium, heating means for including plural heat-generating members which are two-dimensionally arranged such that the heat-generating members are lined up along two parallel lines or more which are vertical to a transport direction of the medium and divided at locations on the parallel lines, 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 heating control means for selecting a group of the heat-generating members which are lined up in the two-dimensional arrangement, conducting the selected group of the heat-generating members, and controlling the heating means.

The heating apparatus including a plurality of heat generation members including first, second and third generation members, the second heat generation member and the third heat generation member having lengths in a longitudinal direction shorter than a length of the first heat generation member, the heating apparatus including first, second, third, and fourth contacts, and a first switching unit configured to bring an electric path between the second contact and the fourth contact into one of a connecting state and an open state.

A fixing device including a belt having an endless shape, a heater provided on an inner surface side of the belt, and a pressing portion provided so as to contact the belt and form a nip portion. A groove-forming portion is provided so as to contact the belt. The groove-forming portion has a surface and a groove formed on the surface. The groove extends in a direction crossing a rotating direction of the belt.

A fixing device includes an endless belt that is heated and movable in a circulating manner, a fixing unit that is fixed in contact with an inner peripheral surface of the belt, a pressure roller that presses the belt against the fixing unit to form a fixing portion through which a recording material on which an unfixed image is formed is to pass and is rotationally driven, and a support roller that is disposed on an upstream side of the fixing unit in a moving direction of the belt and supports the belt to allow the belt to be rotatable, in which the fixing unit includes a first curved surface that is an arc-shaped curved surface formed on an upstream side of a position at which the fixing portion is formed in the moving direction and a second curved surface that is an arc-shaped curved surface formed on an upstream side of the first curved surface in the moving direction, and satisfies a condition of r1>r2 in a case where a curvature radius of the first curved surface is denoted by r1 (mm) and a curvature radius of the second curved surface is denoted by r2 (mm), and the belt is spanned over the support roller and the first curved surface in a state where tension is applied to the belt.

A fixing device includes a moving member that circularly moves, a pressure applying member that is disposed to be in contact with an outer peripheral surface of the moving member, that is used to press a recording medium on which an image is formed, that rotates as the pressure applying member receives a driving force from a drive source, and that presses the recording medium passing through a contact portion between the outer peripheral surface and the pressure applying member, a pressing member that is disposed inside the moving member, that is urged toward the pressure applying member, that is pressed against the pressure applying member with the moving member interposed therebetween, and that is provided to be movable in a direction away from the pressure applying member, and a restriction portion that restricts movement of the pressure applying member that is caused to move in a direction away from the outer peripheral surface of the moving member as the driving force is transmitted from the drive source to the pressure applying member.