Apparatus for measuring the square footage output of diazo printing machines and the like

Claim 1

Apparatus for use in measuring the square footage output of a light-sensitive copy machine of a type having a rotatably-driven drive roller for feeding copy paper rolls of varying widths into the machine, the apparatus comprising: a measuring wheel roller of a preselected diameter rotatably carried by said machine in position to contact said drive roller whereby paper fed into the machine by said drive roller is capable of rotatably driving said wheel roller, a magnetic switch means having a permanently-polarized magnetic switch arm disposed in close proximity to said wheel roller at a radially-spaced distance from its rotatable axis, electrically-energized circuit means coupled to said switch means, a permanently-polarized magnet mounted on said wheel roller at a radially-spaced disposition from its rotatable axis, said magnet being sufficiently small to occupy a limited arcuate portion of said wheel roller circumference whereby, during each rotation of said wheel roller said magnet is moved into close proximity with said magnetic switch arm, said magnet being of sufficient strength and appropriate polarity for magnetically activating said switch means when in said close proximity and for deactivating the switch means during other rotary dispositions whereby said switch is activated once during each revolution of said wheel roller for providing a count of said revolutions, and means coupled into said circuit for counting said revolutions; said preselected diameter of said wheel being determined by the width of each copy paper roll fed into the machine, the relationship of said diameter to the width of the roll being such that each revolution of said wheel roller represents one square foot of the copy paper being fed into the machine.