Exposure control system for photocomposition machines
AssigneeAddressograph Multigraph Corporation
InventorsThomas Allan Booth, Frank Lynn Scholten
Life of this patent
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Abstract
In photocomposition, when change in point size is made, rather than change iris opening, a programmable flash intensity provides the required irradiance. Iris setting is made only to compensate for film or paper sensitivity, flash lamp efficiency, and energy storage capacitor variations.
Claims2
In a photocomposition machine, an exposure control system for providing irradiance of an optically projected image, of an intensity which will provide full exposure of a photosensitive receptor for a selected area of the image in a predetermined time on an image plane, comprising:
- a font means for providing at least one font of characters to be projected and presenting individual characters at a projection location;
- a projection light source to illuminate said font of characters;
- a variable magnification lens system for producing the desired projected size of the character and for projecting the illuminated character from said font means to an image plane;
- said light source being a high-intensity and short-duration flash coordinated to fire when a selected character of the font reaches a projection position relative to said lens system;
- a register for storing a digital number representative of the particular point size to be projected;
- a controller means for accepting input coding impelling the register to output to a digital-to-analog converter;
- and
- means for utilizing the analog output to supply a corresponding level of electrical energy to said projection light source.
In a photocomposition machine, an exposure control system for providing irradiance of an optically projected image, of an intensity which will provide full exposure of a photosensitive receptor for a selected area of the image in a predetermined time on an image plane, comprising:
- a font means for providing at least one font of characters to be projected and presenting individual characters at a projection location;
- a projection light source to illuminate said font of characters;
- a variable magnification lens system for producing the desired projected size of the character and for projecting the illuminated character from said font means to an image plane;
- said light source being a high-intensity and short-duration flash having an output radiance variable in proportion to applied voltage and coordinated to fire when a selected character of the font reaches a projection position relative to said lens system;
- a register for storing a digital number representative of the particular point size to be projected;
- a controller means for accepting input coding and impelling the register to output to a digital-to-analog converter;
- and
- means for utilizing the analog output to supply a corresponding level of electrical energy to said projection light source.
Dependencies are inferred from the claim text.