Fixing device and image forming apparatus having nip pad including a center bend line

An image forming apparatus comprising:

• an image bearer to bear a toner image;
• and
• a fixing device disposed downstream from the image bearer in a recording medium conveyance direction to fix the toner image on a recording medium,
• the fixing device including:
• a fixing belt rotatable in a rotation direction;
• an abutment contacting an outer circumferential surface of the fixing belt;
• a nip formation pad, disposed inside the fixing belt, to press in a pressing direction against the abutment via the fixing belt to form a fixing nip between the fixing belt and the abutment, the nip formation pad to bear a lubricant interposed between the nip formation pad and an inner circumferential surface of the fixing belt,
• the nip formation pad including:
• a first face to form the fixing nip, the first face over which the inner circumferential surface of the fixing belt slides;
• a second face being disposed upstream from the first face in the rotation direction of the fixing belt and defining a predetermined angle relative to the first face, the second face including an entry bent face that is bent at a bend line at a center in a longitudinal direction of the nip formation pad, at least a portion of the bend line extending out of a plane formed by the pressing direction and the longitudinal direction;
• and
• a bent portion coupling the first face to the second face;
• a lateral end accumulation portion defined by the second face and the bent portion of the nip formation pad and the inner circumferential surface of the fixing belt and accumulated with the lubricant in a first amount;
• and
• a center accumulation portion defined by the second face and the bent portion of the nip formation pad and the inner circumferential surface of the fixing belt and disposed inboard from the lateral end accumulation portion in an axial direction of the fixing belt, the center accumulation portion being accumulated with the lubricant in a second amount greater than the first amount, wherein
• the lateral end accumulation portion and the center accumulation portion each extend to a start point of the first face that forms the fixing nip.

A fixing device comprising:

• a fixing belt rotatable in a rotation direction;
• an abutment contacting an outer circumferential surface of the fixing belt;
• a nip formation pad, disposed inside the fixing belt, to press against the abutment via the fixing belt to form a fixing nip between the fixing belt and the abutment, the nip formation pad to bear a lubricant interposed between the nip formation pad and an inner circumferential surface of the fixing belt,
• the nip formation pad including:
• a first face to form the fixing nip, the first face over which the inner circumferential surface of the fixing belt slides;
• a second face being disposed upstream from the first face in the rotation direction of the fixing belt and defining a predetermined angle relative to the first face;
• and
• a bent portion coupling the first face to the second face;
• a lateral end accumulation portion defined by the second face and the bent portion of the nip formation pad and the inner circumferential surface of the fixing belt and accumulated with the lubricant in a first amount;
• and
• a center accumulation portion defined by the second face and the bent portion of the nip formation pad and the inner circumferential surface of the fixing belt and disposed inboard from the lateral end accumulation portion in an axial direction of the fixing belt, the center accumulation portion being accumulated with the lubricant in a second amount greater than the first amount,
• wherein the bent portion is curved, and
• wherein a radius of curvature of the bent portion that is curved decreases from an arbitrary position on the nip formation pad in the rotation direction of the fixing belt, at which the radius of curvature is maximum, to the lateral end accumulation portion in the axial direction of the fixing belt.