Font strip and retaining mechanism for a photocomposing machine

Claim 1

A photocomposing machine comprising, in combination: a. a rotatable character drum for presenting typographical characters in succession to an optical system for imaging onto a sensitized medium, said drum including a cylindrical member and means for guiding and removably retaining, on said cylindrical member at least one character carrier on which is arranged at least one font of said typographical characters, said guiding means including a plurality of guide pins disposed around and protruding from the periphery of said cylindrical member, and said retaining means comprising: 1. at least one stationary retaining pin rigidly attached to and protruding from the peripheral surface of said cylindrical member; 2. at least one movable retaining pin; and 3. pin mounting means for supporting said movable retaining pin on said cylindrical member, comprising: i. a supporting block having said movable retaining pin rigidly attached thereto; ii. means for holding said block to said cylindrical member while permitting sliding movement in the circumferential direction of said cylindrical member; and iii. spring means for biasing said block tangentially to the peripheral surface of said cylindrical member, such that said movable retaining pin is urged in a circumferential direction away from the position of said stationary pin; and b. at least one character carrier comprising: 1. a flexible band of material having disposed thereon two longitudinal successions of elements aligned in laterally displaced relation, the elements of one longitudinal succession being typographical characters and the elements of the other longitudinal succession being timing marks, said two longitudinal successions of elements being arranged substantially adjacent to each other along one side of said band of material and having an optical transmissivity opposite to that of the remaining portion of said band of material, said band of material having a plurality of guide apertures, located adjacent and along said other side thereof, for receiving said guide pins of said character drum, and said band of material having at least one retaining aperture, located at each end thereof, for receiving said stationary and said movable retaining pins, respectively; and 2. at least one rigid supporting strip adjacent said retaining aperture to prevent said band of material from turning.