Abstract: Backing boards are delivered one at a time from a supply hopper to a stack of printed paper sheets at the stacking station outfeed end of a printing press while the outfeed of the next succeeding printed sheet is delayed for a time sufficient to allow the backing board to be delivered onto the stack. In one embodiment, the delay is achieved by stopping delivery of a blank sheet to the printing station of the press. In another embodiment, the delay is achieved by extending an arm into the path of gravity fall of the printed paper sheet toward the stack. A plurality of groups of printed sheets, each provided with a backing board, thus may be assembled in the stack. If the stack is to be bonded together with adhesive at one edge, a cutting line is installed at each backing board to facilitate cutting the adhesive layer to form a plurality of pads. The board inserting apparatus is supported on a vertically adjustable housing to adapt it to various types and sizes of commercial printing presses.

Abstract: A vertical stack of envelopes is produced adjacent the infeed end of a printing press, for removal one at a time by envelope infeed mechanism of the printing press, the stack being maintained by adding envelopes one at a time to the bottom end of the stack when the height of the stack or number of envelopes in the stack is reduced to a predetermined magnitude, the rear end of the stack being elevated to facilitate insertion of added envelopes to the bottom of the stack. The envelopes are removed one at a time by operation of the envelope infeed mechanism of the printing press. The addition of envelopes to the stack is stopped when the height of the stack or number of envelopes in the stack is increased to a predetermined magnitude.