Accumulator apparatus and method having improved sheet registration

Abstract

An accumulator apparatus and method are provided for accumulating sheet articles. The accumulator apparatus includes an upper belt system and lower belt system operative for advancing sheet articles in seriatim manner therebetween. Guide rollers are provided at the entrance of the sheet articles between the upper and lower belt systems for guiding the sheet articles therebetween without pinching. Nip rollers are provided downstream from the entry guide rollers for pulling sheet articles into the accumulator apparatus between the guide rollers and the nip rollers. A ramp system operative for deflecting advancing sheet articles is provided downstream from the nip rollers. Sheet articles deflected by the ramp assembly can then be accumulated in an accumulation location where the lower belt system is maintained in a spaced-apart position below the accumulation location such that the lower belt system cannot contact or mark sheet articles accumulated therein. Stop rollers are provided for selectively stopping further advancement of accumulated sheet articles from the accumulation location and for pulling the accumulated sheet articles from the accumulation location to advance the sheet articles from the accumulator apparatus. A biasing element is provided and is affixed to the downstream end of the ramp. The function of the biasing element is to urge all accumulating sheet articles from behind towards and into the nip formed by the upper and lower stop rollers. The biasing element is provided to reduce or eliminate sheet misregistration or shingling back.

Dependencies are inferred from the claim text.