Photocomposition machine with improved lens control system

A photocomposition machine comprising:

• input peripheral means for providing data representative of selected input commands, values and type characters, said input commands including point size commands for specified type characters within a type line,
• memory means for storing entered data,
• input/output means for entering and reading from said memory means data including said point size command and associated value data provided from said input peripheral means,
• means for storing an optically accessible plurality of predetermined type characters,
• photosensitive means for recording selected type characters,
• controllable flash means in operative relationship with said character storage means for exposing said photosensitive means with images of selected characters of said character storage means,
• controllable optical means for projecting said selected characters in the form of images onto said photosensitive means and including first and second movable lens means for determining the image size of the selected type characters projected onto said photosensitive means,
• first and second motive means for moving said first and second lens means, respectively, in response to corresponding lens position control signals,
• said memory means including means for storing data corresponding to the previously selected point size value,
• control means for providing first and second lens control signals, each representative of the difference between the lens position of the previously selected point size value and the lens position of the newly selected point size value, and
• said first and second motive means moving said first and second lens means respectively to corresponding new positions in response to said corresponding lens position control signals.