| 摘要 |
A pulse generating mechanism, for a photosensitive web-roll mounted for rotation within a light-tight cartridge, comprises a flange on the web-roll; a plurality of activating means on the flange that are equally spaced angularly from each other and radially from the flange center; and sensing means disposed outside the cartridge for sensing movement of each activating means therepast, upon incremental rotation of the flange and web-roll, and for generating pulses in response to said sensing for monitoring quantity of web remaining on the web-roll. Each activating means preferably comprises a ferromagnetic or electrically conductive element on the flange, and the sensing means preferably comprises a transducer for sensing presence of that element. The element can be a ferromagnetic or electrically conductive disc affixed to the flange or spaced bosses on a flange made of ferromagnetic or electrically conductive material. |
