Patent GB-735863-A (GB)
Title: Improvements in or relating to photographic type-composing machines
IPC: B41B21/36
Filed: 1952-01-23
Abstract: 735,863. Photographic type-composing. HIGONNET, R. A. E., and MOYROUD, L. M. Jan. 19, 1953 [Jan. 23, 1952], No. 1891/52. Class 98(1). [Also in Group XL (b)] A photographic type-composing machine comprises means for advancing a light-sensitive surface continuously during projection of a line of characters through a position in which character images may be projected separately thereon and means for projecting character images separately upon the light-sensitive surface at time intervals such that the lightsensitive surface advances, during the interval between successive projections, a distance equal to the width of the preceding image. As shown, the line of characters to be printed on the lightsensitive surface P is " set up " by means of a keyboard 2 operating a register 8 which is of the form described in Specification 691,761 and comprises a plurality of vertical rows of pins each movable axially between an advanced and a retracted position so that each character may be represented as a code by advancing certain of the pins in a row. Each row is then sensed in turn by a reading carriage 12 which detects the position of the pins in storage unit 8, and is movable along the register 8 by means of an electromagnetically operated ratchet and pawl mechanism 18. The reading carriage 12 energizes a selected combination of solenoids 38-52 in accordance with the pin setting representing the particular character to be printed. The supply leads 22-28 feeding solenoids 38-44 also supply solenoids 54-60 and the combination of these leads energized represents the width of the character to be printed in binary notation. The film on which the character is to be printed is advanced sideways by a carriage 104 driven by a continuously rotating motor 82 through a rack and pinion 102. At the completion of one line of characters the film may be advanced in a direction at right angles to the line of printing by a toothed drum 108. Solenoids 38-52 each position axially one of a number of cylinders 130 carrying two circumferential rows of apertures so that for any combination of energization of the leads a light beam from an annular discharge tube 122 is able to pass through one row of apertures only to project a selected transparent character on a cylinder 110 on to the photographic surface. A lens holder 116 carries as many lenses as there are characters to project the appropriate character. The character on the cylinder 110 may be predistorted so that the subsequent projection by the inclined lens will produce a correctly shaped print. Pulses are generated at a rate proportional to the speed of rotation of the motor by a chopping plate 86 driven by the motor and interrupting light reaching a photoelectric cell 82. The amplified photo-cell output pulses are counted in a four-bank binary counter 62 which produces an output pulse when one more pulse than the bank can count is received and the stages are so interconnected that the output pulse resets the entire bank to zero. The output pulse energizes a flash circuit which flashes a lamp 122 to project the character selected by the solenoids 38-52 on to the photographic surface. After a delay imposed by a circuit 78 the flashing pulse is fed to all the banks of the counter which have not been isolated by solenoids 54-60. Hence the counter is set to the difference of the width of the character just printed and the total capacity of the counter. At the same time electromagnet 18 steps reading head 12 on to the next character to be printed in the register 8. The flashing pulse is then fed through a second delay circuit 80 to register a first pulse on the counter. Counting of the photo-cell output pulses continues until one pulse more than the capacity of the counter has been produced, that is until a number of pulses equal to the width of the character just registered has been produced. The output pulse from the counter to the flashcircuit then prints the next character relays 54-60 being set in accordance with the width of this next character. Specification 669,531 also is referred to.