Laser photocomposition system and method

A photocomposing device comprising, in combination, a laser source for producing a laser beam, a reversibly rotatable mirror and a drive system for rotating said mirror to deflect said beam in the direction of a line of composition, a vertical stroking deflector for repeatedly scanning said beam over a relatively short distance transverse to said first direction, means for substantially completely blocking the transmission of said laser beam at selected times to cause the scanning movements of said beam to form lines of proportionally-spaced characters on a photo-sensitive surface, reticle means located in fixed relationship to said surface, means for separating out a portion of said laser beam, guide means for vertically aligning said portion with the modulated beam inpinging upon said rotatable mirror, and separating said beam portion from the modulated beam so that said beam portion remains vertically aligned with said modulated beam after deflection by said rotatable mirror.

A photocomposition method comprising the steps of generating a thin laser beam, projecting said laser beam onto a photo-sensitive surface while moving the beam linearly in the direction of a line of characters, and transversely to the first-named direction at a relatively greater speed with oscillatory motions, and substantially completely blocking the transmission of the beam at pre-determined times to form and proportionally space character images on said surface.

A photocomposing device comprising, in combination, a laser source for producing a laxer beam, sweep means for sweeping said beam in a linear path in the direction of a line of characters to be composed, scanning means for simultaneously and rapidly scanning said beam back and forth in a second direction transverse to the first-named direction, modulating means for modulating the intensity of said beam in accordance with a pre-determined pattern in order to cause said laser beam to form character images on a photosensitive surface, means for detecting the height of said characters in said line, means for varying the scanning distance of said beam directly with said height, and means for varying the speed of sweeping said beam inversely with said height.

A photocomposition method comprising the steps of providing a laser beam source, moving said beam rapidly back and forth in a first direction to produce a scanning motion in the direction of the height of said characters, moving said beam in a second direction tranverse to said first direction to produce a sweeping motion in the direction of a line of said characters, projecting said beam onto a photosensitive surface while blanking it at pre-determined times to produce lines of proportionally-spaced character images on said surface measuring the height of the characters in a line, varying the extend of said scanning motion directly with said height, and varying the speed of said sweeping motion inversely with said height.

A photocomposition device comprising, in combination, a laser source for producing a laser beam, first deflection means for sweeping said laser beam across a photosensitive surface in the direction of a line of characters, second deflection means for scanning said beam back and forth in a second direction transverse to the first-named direction at a speed substantially greater than the speed at which said beam is swept by said first deflection means, modulation means for modulating the intensity of said beam during the scanning motion produced by said second deflection means so as to produce and proportionally space character images on said photosensitive surface, said second deflection means comprising a body of refractive material responsive to electrical signals to deflect said beam through varying angles.

A photocomposing device comprising, in combination, a laser source for producing a laser beam, sweep means for sweeping said beam in a linear path in the direction of a line of characters to be composed, scanning means for simultaneously and rapidly scanning said beam back and forth in a second direction transverse to the first-named direction, modulating means for modulating the intensity of said beam in accordance with a pre-determined pattern in order to cause said laser beam to form character images on a photosensitive surface, locating means for indicating the location of said laser beam in the direction of said line by producing an electrical pulse for each small increment of distance moved from a reference point which is fixed relative to said photosensitive surface during photocomposition, and means for starting each back-and-forth scanning movement with one of said pulses.