| 摘要 |
PURPOSE:To surely detect a sheet film with a simple structure, by detecting diffused light of the sheet film or reflecting member and presence/absence of the sheet film in a cassette from the difference in the fed-back quantity of the light. CONSTITUTION:The back plate 5b of a cassette 5 is opened in a dark place and near infrared or infrared rays are projected into the cassette 5 from a light emitting section 19 provided on a position outside of the opening operation area of the cassette 5. When a sheet film exists in the cassette 5, the rays are reflected by the sheet film and, when no sheet film exists in the cassette, the rays are reflected by a reflecting member 21 and the diffused light is detected by means of another light emitting section 20 which is also provided on a position outside of the opening operation area of the cassette 5. Since the fed-back quantity of the diffused light is different between the sheet film and member 21, presence/absence of a sheet film in the cassette 5 can be discriminated. Therefore, existence of a sheet film can be confirmed surely when the reflecting member 21 is used. |
