Belt cleaning device (4) has a brush roller (41). Some of the rollers (41) Hair (412) contacts the endless belt (23). Some of the bristles (412) is immersed in the cleaning liquid in the tub (42). Since roller (41) is rotated in a direction opposite to the movement direction of the belt (23), the liquid is scooped up by the hair (412) to clean the belt (23). Roller (41) has a brush shaft (411) having a plurality of holes (411b). Hole (411b) is at a pitch of 3-4mm in the axial direction, it is formed in a zigzag shape at a pitch of 3-7 degrees in the circumferential direction. Hair which is planted in the hole (411b) (412) has a free length of the diameter and 15-20mm in 0.05-0.20Mm. When the roller (41) is rotated, the hair (412) the linear velocity at the tip is 120.8-201.3mm / s. The device (4) is removed without leaving ink adhering to the belt (23) surface.