Device for controlling the feeding of copy sheets to a small offset printing machine

Claim 1

For use with an offset printing machine of the type including a rotatable cylinder making one complete revolution during each printing of a copy sheet, feeding means operable to feed copy sheets to be printed in synchronized relation with rotation of the cylinder, and means operable to etch and ink a master cylinder as an initial printing operation step; a device for controlling the feeding of copy sheets, comprising, in combination, operating means controlling activation and deactivation of said feeding means; start means connected to a source of electric potential and operable to supply a start print signal; timing means connected to said start means and activated by said start print signal, said timing means, when thus activated, being operable to supply a time signal at the completion of the etching and inking operation; pulse generating means operatively associated with said rotatable cylinder and providing a synchronizing pulse each time said rotatable cylinder completes one such revolution; a logic circuit connected to said start means, said timing means and said pulse generating means; said logic circuit including a first flip-flop having a set input and a clear input, a set output producing a 1 signal responsive to a ''''set'''' input signal, and a clear output producing a 1 signal responsive to a ''''clear'''' input signal, with each output producing a 0 signal when the other output produces a 1 signal, and a plurality of AND members each having first inputs connected in parallel to said pulse generating means to receive said synchronizing pulses, said AND members including a first AND member having a second input connected to said timing means, a third input connected to said clear output of said first flipflop, and an output, and further including a second AND member having a second input connected directly to said start means in parallel with said timing means, a third input connected to said set output of said first flip-flop, and an output; said logic circuit further including a first OR member having respective inputs connected to the outputs of said first and second AND members and having an output; logic means connecting said first OR member output to said operating means to activate said feeding means responsive to an output signal from said first OR member; said logic circuit also including a delay circuit connecting the output of said first AND member to the set input of said first flip-flop; and temporary stop means connected to said source and to said logic means and operable to supply a stop print signal to said logic means to deactivate said feeding means following activation of said feeding means responsive to a start print signal; whereby, responsive to operation of said start means, said timing means supplies a time signal to said first AND member, said clear output provides a 1 signal to said first AND member, and, upon receipt of a synchronizing pulse at its first input, said first AND member applies an output signal to said first OR member to activate said feeding means, and supplies an output signal through said delay circuit to said set input of said first flip-flop to change the signal at said set output thereof to 1; said start means, when operated following operation of said temporary stop means, supplying an input signal directly To the second input of said second AND member with the third input of said second AND member being supplied with a 1 signal from said set output of said first flip-flop so that, upon receipt of a synchronizing pulse at its first input, said second AND member supplies an output signal to said first OR member to re-activate said feeding means.