Photo composing machine and method for making plates from microfilm

Claim 1

A machine for making plate material for printing one side of a book signature from microfilm wherein selected microfilm frames are exposed onto preselected positions on said material large enough to receive a plurality of exposures of said frames, said microfilm having marginal spots opposite at least certain frames, comprising a base, a rectangular vacuum table, a chase having a rectangular opening of substantially lesser area than said table, first support means for supporting said table for longitudinal movement relative to said base, first drive means for moving said table relative to said base along a first axis parallel to said base, second support means for supporting said chase for transverse movement relative to said table, second drive means independent of said first drive means for moving said chase in infinite gradations relative to said table along a second axis transverse to said first axis and parallel to said base, a vertical support extending upward from and movable with said chase, an enlarger vertically movably mounted on said support above said opening along a third axis transverse to said first and second axes and to said base and having an enlarger lamp, a lens and a microFilm transport between said lamp and lens whereby frames of microfilm are moved into position for exposure by said lamp and focused by said lens onto materials on said table, said transport comprising a transport frame having an exposure section having an aperture aligned with said opening, said lamp and said lens, a film support section supporting microfilm on one side of said exposure section, a film takeup section on the side of said exposure section opposite said one section and having film rollers for driving film from said support section and past said aperture in said exposure section, a reversible motor for driving said film rollers, and electrical means for controlling said motor to move said microfilm and locate a frame of microfilm at said aperture, said machine exposing on said table images of said frames, each image being of a size up to the size of said opening, said machine being capable of exposing a plurality of said images upon a plate held on said table to make up a pattern on said plate to print one side of a book signature, a light at said exposure section positioned to direct light through the margin of said microfilm, a photocell sensitive to light from said light and positioned to be affected by one of said spots, said photocell comprising a portion of said electrical means and said electrical means stopping said motor when said frame is centered relative to said aperture, a gear train and one-way clutches between said motor and said film rollers, a second light and a second photocell receiving light from said second light unless obstructed by one of said spots, said second photocell comprising a portion of said electrical means and said electrical means slowing said film rollers as said frame approaches the center of said aperture.