| 摘要 |
PURPOSE:To improve operability by giving an alarm while inhibiting a film from moving even if a key for moving back information frames by one frame or one information frame group is operated while a starting information frame is re- trieved. CONSTITUTION:A microfilm 1 consists of plural information frames K1, K2- Kn, which each have a frame mark MK; when plural frames KG form one piece of information, the starting frames have subject marks MC1, MC2-. To end parts, leader tapes 1a and 1b are connected through a start mark MS and an mark ME respectively. A key at the input part of the retrieval device which is not shown in the figure is operated to access a desired information frame Ki or subject mark MCi, thereby projecting the information on a screen. In this case, even if a key for moving back the film by one information frame or information frame group is operated during the retrieval of a starting information frame, the film is inhibited from moving and a warning of the erroneous operation is given. Thus the operability is improved. |
