Abstract: A signal reproduction apparatus comprising a pick-up means with a playback stylus tracing on engraved grooves of a record disk and a shaving means abutting on only the top portions of several number of the engraved grooves, wherein the shaving means effectively scrapes dust on the disk surface during the tracing movement in advance of the tracking motion of the playback stylus along the engraved grooves.

Abstract: A method of producing a plate-shaped body, particularly a video disc in which circumferential warp in the thicknesswise direction, thickness fluctuation and deflection of the signal track are minimized comprisingThe steps of pressing by a mold a thermoplastic resin which has been heated to a temperature above the softening point thereof, and cooling the thermoplastic resin to solidify the same. During the cooling, the pressure of the mold is decreased to a low level when the thermoplastic resin has been cooled down to a temperature around the softening point. The thermoplastic resin is allowed to be solidified without any substantial and local residual stress to ensure minimal circumferential warp, thickness fluctuation and deflection signal track.

Abstract: A recording-reproducing system comprising a flexible jacket containing a record disk, a turn table rotating said record disk, an engaging means engaged to one end of said record disk in said jacket, a stopping means for restricting only the movement of said record disk, and a thrust means for transferring said jacket, whereby said record disk can be taken out of said jacket within the reproducing system.