Abstract: A reinforcing unit that is mounted on a main body frame includes a beam material, and one or more reinforcing members that are mounted on an outside of the beam material, in which the beam material substantially has a continuously closed cross-sectional shape that includes an inner surface portion that is provided on a frame side where the main body frame is located, an outer surface portion that is provided on a counter-frame side that is a side opposite to the main body frame, and a side surface portion that connects the inner surface portion and the outer surface portion, and the reinforcing member restrains bulging deformation of the side surface portion in a case where an impact load is input to the outer surface portion.

Abstract: A composition comprising 70% by weight or less of magnetic particles and 30% by weight or more of a resin mixture of (a) an epoxy resin, (b) a phenol resin and (c) polyvinyl butyral, the weight ratios of the resin components being (b)/(a)=2.5/7.5 to 4/6 and (c)/(a)+(b)=2.5/7.5 to 4/6, can give a thick magnetic recording medium excellent in film strength, resistance to cracks and durability by screen printing by one coating.