In the printing and die cutting of flat articles such as, for example, corrugated sheets or "blanks" which are subsequently folded and glued to form boxes and other forms of containers, it is well known to position a stacker, or so-called "stacker-conveyor," at the discharge of the last section of the printing and/or processing machine; the last section of the production machine usually being a die cutter section which slots the printed container blanks and forms the necessary flaps and tabs. The purpose of the stacker-conveyor is to convey the blanks from the last section of the production machine to a spaced-apart location at which the blanks are stacked upon each other to form vertical stacks which are then banded and removed to a further location for shipping.
Because the printing and/or processing machines, including the die cutter section, operate at very high production speeds such as, for example, at output speeds of 1,000 feet per minute, there has long been a serious problem with the discharge end of the stacker-conveyors. That is, while the conveyor portion may be matched in speed to that of the production machine, the discharge or exit velocities of the blanks are so high that the leading edge of the blanks become seriously damaged as they strike the abutment wall defining the forward vertical line of the stacked pile of blanks. Many prior attempts have been made to solve this problem, but none have been satisfactory.
USPTO Backgrounds
USPTO Backgrounds