A thermal fixing apparatus, including a rotatable first member; a heater heating the first member; a rotatable second member forming a nip portion with the first member; and a pressurizing member disposed inside the first member, and having a contact surface with an inner surface of the first member. The pressurizing member includes a surface layer constituting the contact surface, and the surface layer comprises a diamond-like carbon film containing a hydrogen atom (H), a carbon atom (C) and a silicon atom (Si). 100×(H)/((H)+(C)) is 5 or less. 100×(Si)/((Si)+(C)) is 1 to 20. Between the contact surface and an inner circumferential surface of the first member, an oil film containing a fluorinated oil and a silicone oil is present.

A fixing unit fixes the toner image on a sheet by causing the sheet carrying a toner image to pass through a nip portion formed by bringing a rotary fixing member and a rotary pressing member into pressure contact with each other. The image forming apparatus includes an image forming apparatus main body having a fixing unit accommodating portion for accommodating the fixing unit in an insertable and removable manner, and a heating unit provided in the image forming apparatus main body and heating a rotary fixing member of the fixing unit mounted on the fixing unit accommodating portion from outside in a radial direction. The direction in which the fixing unit is inserted into and removed from the fixing unit accommodating portion coincides with the axial direction of the rotary pressing member.

A fixing apparatus including: a first rotary member; a second rotary member; a nip forming member; and a heater. The nip forming member includes: a first projection portion inside a nip area; and a second projection portion located outside the nip area. The first and second projection portion abut against the inner circumferential surface of the first rotary member. In a direction orthogonal to a nip tangent, a distance between a tip of the second projection portion and the nip tangent is larger than a distance between a tip of the first projection portion and the nip tangent. The second projection portion extends toward the second rotary member without exceeding the nip tangent. A radius of curvature at a tip portion of the second projection portion is smaller than a radius of an inner circumferential circle of the first rotary member.

A toner image fixing device include a fixing belt; a heating roller training the belt around; a pressing pad of resin material provided inside the belt; a rotatable pressing member contacting the belt and pressing against the pad through the belt to form a nip for nipping and feeding the sheet; a supporting stay supporting the pad and including a surface contacting the pad, one of the pad and the stay being provided with a projection, and the other being provided with a recess engaged with the projection at an engaging position; and a separation plate provided without contact to the belt at a position opposed to the pad downstream of the nip in the sheet feeding direction. A distance between the engaging position and a downstream end of the pad is 0-35% of a length of the pad measured along the feeding direction.

A heating device includes: a rotating body; a heating body as defined herein; and a contact mechanism, in a non-existence state where a material to be heated does not exist between the rotating body and the heating body after the material to be heated passes between the rotating body and the heating body, configured to cause the rotating body to be in contact with the heating body at a central portion of the rotating body in a rotation axis direction of the rotating body, so that an area of the rotating body in contact with the heating body is smaller at each of both end portions of the rotating body than at the central portion of the rotating body in the rotation axis direction, or configured to switch the rotating body between a first contact state and a second contact state as defined herein.

A fixing device includes a roller having a rotation axis, and a belt unit that conveys a sheet in combination with the roller. The belt unit includes an endless belt, a nip forming member that forms a nip in combination with the roller, and an upstream belt guide. The fixing device further includes a chute having a guide surface configured to guide the sheet toward the nip. In a section orthogonal to the rotation axis, a line segment connecting a downstream end of the guide surface and an upstream end of the nip does not intersect the upstream belt guide, and an extended line extended from the downstream end of the guide surface along the guide surface toward the roller intersects a surface of the roller at a position upstream of an upstream end of the nip.

A fixing device includes a fixing rotator over which a recording medium bearing an image is conveyed. A first heater heats the fixing rotator and generates heat evenly in a maximum conveyance span where the recording medium having a maximum width in a width direction of the recording medium is conveyed. The maximum width is available for the fixing rotator. A second heater heats the fixing rotator and generates heat in the maximum conveyance span. The second heater includes a first portion that generates heat in a first heat generation amount and a second portion that generates heat in a second heat generation amount that is greater than the first heat generation amount of the first portion.

A fixing apparatus includes a belt, a pad member, a pressure member, a heating roller, a stretching roller, and, an outer stretching roller. The outer stretching roller disposed between the heating roller and the stretching roller and configured to press the heating roller from an outer surface of the belt and bring the belt into contact with the heating roller. In a cross section orthogonal to a rotation axis of the pressure member, a surface between the heating roller and the stretching roller of the belt in a state where the belt is pushed toward the heating roller by the outer stretching roller is located inside that of the belt in a state where the outer stretching roller is removed.

A fixing device includes a fixing belt configured to heat a recording material, a pressure member configured to press the fixing belt, and a sliding member configured to be in sliding contact with an inner peripheral surface of the fixing belt and being opposed to the pressure member. The pressure member and the fixing belt form a fixing nip portion, and heat and pressure are applied to the recording material at the fixing nip portion to fix a toner image onto the recording material. The sliding member includes a plurality of protrusions on a surface of the sliding member that is in sliding contact with the inner peripheral surface of the fixing belt. The following expressions are satisfied: The fixing belt satisfies the prescribed formula.

A fixing apparatus includes a belt, a rotary member, a pad member, and a slide member. A distance in the conveyance direction between a first position and a second position is 3.0 mm or less. The first position is a downstream edge of a tip of a projection positioned most downstream in a direction of rotation of the belt. The second position is an upstream edge, in the direction of rotation of the belt, of the guide portion that contacts with the inner circumference surface of the belt. A distance in the pressing direction between a third position and a fourth position is 0.4 mm or more and 2.0 mm or less. The third position is the tip of the projection positioned most downstream in the direction of rotation of the belt. The fourth position is the same position as the second position.