A dispenser has a seal disk (30), a valve member (40), a plunger
guide block (50), a motor (3), which rotates a cam-follower guide
block (60), and an end cam (5). The seal disk (30) has communication
holes (31), (32) and a sliding surface (33). The valve member
has a sliding surface (41), three plunger holes (42) and three plungers
(80) inserted in the plunger holes. The cam-follower guide block (60)
has three guide holes (62) that receive cam followers, which each have a
body (70) with a ball (75) within a recess (71). The ball
(75) contacts the cam surface (5A) of the cam (5) which causes
the cam followers and plungers (80) to move back and forth parallel to the
dispenser axis. The coefficient of friction between the ball and the recess is
less than that between the ball and the cam surface (5A).