GB1358337A - Photomechanical camera - Google Patents

Abstract

1358337 Photo-mechanical cameras DAINIPPON SCREEN SEIZO KK 20 Oct 1972 48521/72 Heading G2A In a photo-mechanical camera, a length of film is drawn from a supply roll and conveyed by a perforated belt, on which it is held by suction, to the correct position for exposure. The roll of film (18), Fig. 1 (not shown) is in a cassette housed in the upper part of the camera and a length of film is conveyed downwards by a drive roller pair 21, 22 and a suitable length severed by a cutter (23). This length is now held and transported by a perforated endless belt 24 passing round rollers 25, 26, 27. The front part 24a of this belt is in close contact with the perforated front wall 15 of a suction box 14. The vacuum created inside this box by a pump 31 acting through a conduit 29 holds the film on to the belt. A pressure regulation valve 30 enables two different degrees of vacuum, a higher and a lower, to be applied. A motor 41 drives the perforated belt through a belt and pulley system 38, 37, 35, and also drives the feedroller 21 by a further belt and pulley system 36, 42, 43, 46, 48, 49. This latter system, however, includes a clutch 45, so that the drive can be broken. The various operations are controlled by a relay circuit 32 which itself is controlled by a cam drum 51, the drum having a number of grooves 52, 53, 54 which co-operate with a micro-switch 55 in the relay circuit. Initially the motor 41 is energized, so that film is conveyed between rollers 21, 22, belt 24 is driven, a low degree of vacuum is created in box 14, and cam drum 51 is rotated. The cam drum actuates the cutter to cut off a predetermined length of film, the motor being temporarily de-energized. The motor is then again energized but clutch 45 disengaged, so that the motor drives belt 24, but not roller 21. The film length is carried by belt 24 until it reaches the correct position for exposure, in alignment with the optical axis of the camera. The motor is now once more de-energized, so that the film remains stationary, and valve 30 switches over to the higher degree of vacuum, so that the film is held firmly in position while the exposure is made. The film is now passed downwards to fall into a collecting box.