Font availability system for photocomposing machine

Abstract

A photographic compositor having a letter pattern carrying section comprising a plurality of letter pattern carrying discs which are rotatably mounted on a common rotatable shaft at intervals, and an optical system disposed to cooperate with one side of a selected disc wherein a beam for illuminating letter patterns carried in a track on a disc is caused to reside between a pair of adjacent letter pattern carrying discs by interspersing a selected disc with said optical system and then passing the beam through a letter pattern and out through the space between a pair of discs of the following stage, said optical system and said letter pattern carrying section mounted for relative movement in a path perpendicular to the axis of said rotatable shaft, said movement having a first limit which separates the largest disc carried by said shaft from said optical system, and a second limit position preselected to position a track of any selected disc into projection relationship with said system, and means to shift said letter pattern carrying section in the direction of the shaft axis while said section is in said first limit position; whereby, said plurality of discs may be removed from interface with said optical system, shifted to align a substitute disc, and repositioned to select various tracks on selected discs at will.