MEDIUM POSITIONING MECHANISM

PROBLEM TO BE SOLVED: To provide a compact low-cost and high-reliability medium positioning device which places a shutter in up/down motion associatively with the traveling operation of a magnetic head device without requiring a motor for shutter driving, etc. SOLUTION: A conveyance path 11 for a medium 10 is formed on a base 1, a parallel link mechanism 5 is composed of a shutter 2 which can protrude onto the conveyance path, links 3 and 4, and the base 1, and at least one link 3 is provided integrally with a lever 6. When the magnetic head device 8 which moves orthogonal to the medium conveyance path is at a start position on the base, the parallel link mechanism 5 is rotated with the lever 6 in contact to put the shutter 2 in the base and when the magnetic head device 8 moves by a specific distance L, the parallel link mechanism is separated from the lever 6 to project the shutter 2 onto the base and cut off the conveyance path, thereby positioning the medium.