mechanism to detect the end of tape for tape cartridge capabilities

摘要

A step portion (20) of a notched configuration is provided between the bottom portion of a tape cassette (1) and a tape detection hole (7), and a prism (21) for introducing a light beam emitted from a light-emitting portion (30) is disposed at the step portion (20) so that light beams radiated from the light radiating portions (28,29) of the prism (21) are received by light-receiving portions (12,13), respectively. The prism (21) is formed of a light incident portion for making the light beam emitted from the light-emitting portion incident therein through the side portion of a prism body, a reflection surface for reflecting the light beam incident from the light incident portion in the upper direction, and the light radiating portions (28,29) for splitting the reflected light beam from the reflection surface into two light beams which travel in opposite directions. IMAGE