Paper advancing system for high speed printers

A method and associated apparatus for quickly and accurately advancing paper between the platen and printing mechanism on a line-by-line basis in a high speed printer for printing lines of text including a platen and a printing mechanism disposed adjacent the platen. The method comprises the steps of, threading the paper from the supply input through a powered first drive mechanism disposed before the platen and printing mechanism, through a frictional gripping mechanism disposed adjacent the platen between the platen and the first drive mechanism and adapted for frictionally gripping the paper under a gripping force sufficient to prevent advancement beyond the frictional gripping mechanism by a pushing force on the paper while permitting the paper to be pulled through the frictional gripping mechanism by a second drive mechanism, between the platen and printing mechanism and into engagement with a powered second drive mechanism disposed after the platen and printing mechanism and adapted for gripping and rapidly moving the paper a feed distance; during printing of a line of text by the high speed printer, using the powered first drive mechanism to receive the paper and advance the paper to form a supply loop containing paper for at least one dot line feed distance between the powered first drive mechanism and the frictional gripping mechanism; and, at the time for advancing the paper by the feed distance, using the powered second drive mechanism to pull the paper through the frictional gripping mechanism the feed distance from the supply loop. A novel backlash coupling is employed in the second drive mechanism.