An operation knob that turns a drum is exposed at the outer side of a left side face of a temporary holding section, and a knob cover is disposed at the outer side of the operation knob. When an opening guide of the temporary holding section is in a closed state and is closed onto the upper side of the drum, the knob cover is put into a covering state, via a stud, preventing operation of the operation knob. When the opening guide of the temporary holding section is turned in an opening direction from the closed state and opens apart from the upper side of the drum, the knob cover is turned in an exposing direction by the action of a spring and put into an exposing state.