Roller shaft

A roller shaft for rotatably supporting on a chassis a guide roller mounted in a tape drive, said roller shaft comprising:

• a shaft portion having a substantially solid cylindrical shape and extending in a rotation axis direction from a lower end to an upper end;
• a flange portion having a disk-like shape and formed around said shaft portion at a position apart from said lower end by a predetermined distance to extend in a radial direction perpendicular to said rotation axis;
• and
• positioning and rotation preventing means for positioning said roller shaft with respect to said chassis and for preventing said roller shaft from rotating with respect to said chassis;
• wherein said shaft portion comprises a hollow cylindrical portion formed at the lower end, and said hollow cylindrical portion has a substantially hollow cylindrical shape and an inner peripheral surface on which a female screw is formed;
• wherein said roller shaft is mounted on said chassis by inserting said hollow cylindrical portion in a mounting hole bored in said chassis and by screw-engaging a screw with said female screw;
• and
• wherein said positioning and rotation preventing means comprises a D-shaped cut formed on an outer peripheral wall of said hollow cylindrical portion.