Exposure control device for photographic film printers

Claim 1

A sensor assembly for monitoring light energy projected in series through a pair of film strips from a light source assembly having a light output printing aperture of adjustable width, said sensor assembly comprising: a baffle plate positioned adjacent to and in alignment with the light output printing aperture, so that the pair of film strips are disposed between the baffle plate and the aperture; a plurality of light sensors mounted on said baffle plate so that each of the sensors intercepts a different portion of the light energy transmitted through said light output aperture, and with said plurality of sensors being distributed substantially across the maximum adjustable width of the aperture; signal means coupled to said plurality of sensors for developing a first output signal representative of the light energy passing through said pair of film strips; a first meter coupled to said signal means and responding to said first output signal for providing an indication of the light energy passing through said film strips; whereby the width of the light output printing aperture may be adjusted for a selected value of printing light energy; and said light sensors being semiconductor devices which respond to light energy in a selected frequency interval, and said signal means comprising means for connecting said semiconductor devices in series, whereby the first output signal is substantially a linear representation of the light intensity in said selected frequency interval, passing through said pair of film strips.

Claim 7

A system for controlling the amount of printing light energy projected in series through portions of a pair of films as the films move across a light source assembly, having an adjustable light output aperture and an adjustment control for varying the width of the output aperture, said system comprising: a baffle plate positioned adjacent to and in alignment with the light output aperture so that the films pass between the baffle plate and the light output aperture; a plurality of light sensors mounted on said plate so that each of said sensors intercepts the light energy transmitted through a different section across the width of said light output aperture, and with said plurality of sensors being distributed substantially across the maximum adjustable width of the light output aperture; signal means coupled to said plurality of sensors for developing a first output signal representative of the light intensity passing through portions of the pair of film strips as the film strips pass across the output aperture of the light source; control means coupled to said signal means and to the adjustment control of the light source assembly for varying the width of the light output aperture in response to said first output signal; Pg,19 whereby the amount of printing light energy projected in series through each of the portions of the films as the films pass across the light source assembly is controlled thereby; a light detector assembly mounted on said baffle plate so that said light detector assembly responds to light energy, transmitted through a section of said printing aperture adjacent to a leading edge of the aperture relative to the direction of movement of the film, to produce a second output signal representative of the light intensity received by said light detector assembly; and processor means for generating a third signal representative of the variation of said second signal; wherein said control means further includes circuitry for responding to the third signal to initiate the positioning of the adjustment control in response to the transparency of the film portion passing over the leading edge of the aperture.

Claim 8

A system for controlling the amount of printing light energy projected in series through portions of a pair of films as the films move across a light source assembly, having an adjustable light output aperture and an adjustment control for varying the width of the output aperture, said system comprising: a baffle plate positioned adjacent to and in alignment with the light output aperture so that the films pass between the baffle plate and the light output aperture; a plurality of light sensors mounted on said plate so that each of said sensors intercepts the light energy transmitted through a different section across the width of said light output aperture, and with said plurality of sensors being distributed substantially across the maximum adjustable width of the light output aperture; signal means coupled to said plurality of sensors for developing a first output signal representative of the light intensity passing through portions of the pair of film strips as the film strips pass across the output aperture of the light source; control means coupled to said signal means and to the adjustment control of the light source assembly for varying the width of the light output aperture in response to said first output signal; Pg,19 whereby the amount of printing light energy projected in series through each of the portions of the films as the films pass across the light source assembly is controlled thereby; a light detector assembly mounted on said baffle plate so that said light detector assembly responds to light energy, transmitted through a section of said printing aperture adjacent to a leading edge of the aperture relative to the direction of movement of the film, to produce a second output signal representative of the light intensity received by said light detector assembly; and processor means for generating a third signal representative of the variation of said second signal; wherein said control means further includes circuitry for responding to the third signal to initiate the positioning of the adjustment control in response to the transparency of the film portion passing over the leading edge of the aperture.