JPS5789733A - Film advancing system of camera - Google Patents

Abstract

PURPOSE:To detect a film being loaded improperly by providing a circuit, which generates an inverted output when a counter stops counting during advancing operation, to a camera which takes up a film completely first and rewinds the film in a cartridge on every shot. CONSTITUTION:An invented camera is a preliminary winding type motor driving camera which detects film length automatically to protect an exposed film against an accident. When a film is loaded and a back cover is closed, a power switch SW0, a counter swith SW5 and a mode switch SWc are still closed. When the film is loaded normally, the switch SW2 is opened coupling with a counter; and then, a gate OR holds itself at a level H, and an NAND4 holds itself at a level L to energize a relay RL2 and also to make a motor M reverse continuously (winding). When the loading is abnormal, on the other hand, the output of a 2.5sec timer TM1 goes up to a level L and the output of the NAND4 is inverted to a level H, so the motor stops, displaying abnormal film loading by an alarm AL.