Adjustable size sensing sheet cassette

Automatic printing apparatus including a station for printing an image on a sheet, means for supporting a removable, adjustable sheet cassette containing sheets in a cooperative position in said apparatus, means for feeding a sheet from said adjustable sheet cassette to said printing station, said apparatus including at least one other supply of sheets, said adjustable cassette comprising a sheet stack support platform, said platform being capable of supporting various stacks of sheets of a plurality of length and width dimensions, sheet width and length dimension representing members each independently movable to a plurality of positions representing a plurality of sheet width and length dimensions, a pair of side edge sheet guides in opposed relationship to each other at least one of said side edge sheet guides being movable relative to the other side edge sheet guide, a movable rear edge sheet guide, said at least one movable side and rear edge guides being adjustable to accommodate various stacks of sheets of a plurality of width and length dimensions and means automatically responsive to movement of said at least one movable side and rear edge guides respectively to move said sheet width and length representing members to positions respectively representing a sheet width and a sheet length dimension of the stack of sheets on the platform, the position of said width and length dimension representing members being detectable by detector means on said apparatus, said apparatus including detector means to detect the respective positions of said sheet width and length representing members, said apparatus further including control means to determine the length and width dimensions of a copy sheet in said cassette from the detected respective positions of said sheet width and length dimension representing members to enable said apparatus to automatically select said sheet cassette to supply sheets for a printing operation.