GB1299283A - Paper feeding mechanism for photographic printers - Google Patents

Abstract

1299283 Photo-copying apparatus PAKO CORP 2 June 1970 [6 June 1969] 26649/70 Heading G2A [Also in Division B8] In a photographic printer having a paper supply mechanism 11 and a take-up mechanism 19 with an exposure area A receiving paper 12 to be exposed, there is provided mechanism for feeding precisely adjustable lengths of the paper to and from said area A, the mechanism including a rotatable arm 22 in driving connection with paper feed rollers 13, 14, the effective actuating length of the arm being precisely variable so as to controllably vary the amount of rotation of the rollers 13, 14 when the arm 22 is rotated through a predetermined arc. Tensioning rollers 16, 17 are provided to keep the paper taut in the exposure area A. The arm 22 is provided with an adjusting slide 23 to which one end of a chain 20, driving the rollers 14, 17, is pivotably connected, the other end of the chain being connected to a return spring 21. The slide 23 is meshed with a worm 24 which is rotated by a control knob 26. The arm 22 is rotated through a complete circle by a single revolution type clutch mechanism 27, Figs.2, 3 (not shown). Sequence of operations. The arm 22 starts from the vertical position shown in Fig.1. As it rotates clockwise, the speed of the chain 20 will gradually accelerate until it reaches a maximum when the arm 22 has rotated through 90 degrees. Thereafter the chain decelerates for the next 90 degrees of rotation. As the arm 22 finishes a complete circle, the chain 20 is returned to its initial position by the spring 21 under control of the arm 22. Over-running clutches (35) permit return of the chain without reversing the rollers 14, 17. An anti-backlash over-running clutch mechanism (34a) is associated with the arm 22. An identifying number stamp mechanism 15 and control circuit are also provided, the latter effecting an exposure after each revolution of the arm 22.