To simplify fitting of a contact member provided for simplified rotation preventing means for a non-mounting time installed in parallel.SOLUTION: A shaft body 70 for locking having a locking member 71 is inserted in a drive shaft fitting hole 23a of a rotary shaft 23 in a shaft direction movable state, a mooring member 60 is installed on an inner bottom surface of a container part 21 and a shaft body 70 for locking is made to go around many uneven parts 61 for mooring. In a cassette free state, the shaft body 70 for engagement is energized by an energizing member 72 on the bottom of the drive shaft fitting hole 23a and the locking member 71 is locked with the uneven parts 61 for mooring, whereas the locking member 71 is removed from the uneven parts 61 for mooring by suppressing energization in the cassette fitting state, and a chevron-shaped thrust member 62 having a gently rising plane and a steep lowering plane is provided for an outer peripheral side of the uneven parts 61 for mooring is provided. A circular ring-like part 82 of a contact member 80 having a contact part 81 is externally fitted to the rotary shaft 23, and the contact part 81 intermittently interferes the thrust member 62 as the rotary shaft 23 axially rotates.SELECTED DRAWING: Figure 1【課題】簡素化した非装着時回転阻止手段に並設される当接部材の取付容易化。【解決手段】係止部７１を持った係止用軸体７０を回転軸２３の駆動軸嵌入孔２３ａに軸方向移動可能状態で挿入し、係留部材６０を容器部２１の内底面に装備して多数の係留用凹凸６１に係止用軸体７０を一周させ、カセット自由状態では係止用軸体７０を駆動軸嵌入孔２３ａの底の付勢部材７２にて付勢して係止部７１を係留用凹凸６１に係合させる一方、カセット装着状態では付勢を抑えて係止部７１を係留用凹凸６１から離脱させるようにしたうえで、更に、上面に緩慢な上り面と急峻な下り面とを持った山形の衝上部材６２を係留用凹凸６１の外周側に設けるとともに、当接部８１を持った当接部材８０の円輪状部８２を回転軸２３に外嵌して、回転軸２３の軸回転に伴って当接部８１が衝上部材６２と間欠的に干渉するようにする。【選択図】 図１
