An image forming method for fixing a toner image on a recording medium by passing the recording medium through a fixing nip defined between a first member and a second member under heat and pressure. The toner includes a specific amount of a shear buffer. The first and second members extend along respective first and second longitudinal axes, and have respective at least one convex portion curving outward and at least one concave portion curving inward with respect to each of the respective first and second longitudinal axes. At least one of the first and second members is heated, and the first convex portion engages the second concave portion and the first concave portion engages the second convex portion, to define the fixing nip therebetween.