Abstract: A paper feeder employs a retard roll mounted on a shaft that is controlled by a magneto rheological variable clutch. Current is adjusted to the magneto rheological variable clutch to produce a variable drag torque (from near zero to fully locked) on the retard roll. The current is adjusted based on various inputs, some of which include media type, temperature, humidity, media size, and transport speed. Variable drag on the retard roll results in a reduction in induced skew of sheet passing through a nip formed between the retard roll and a separation roll, as well as, less and more consistent wear of the retard roll.

Abstract: An apparatus monitors the motion of sheet, such as in a digital printer. An optical sensor is capable of recording an image in a two-dimensional array of pixels, and has acuity to recognize a terrain of a small area on a sheet that is substantially blank to a human eye. The optical sensor views a portion of a sheet moving in a process direction through a path. A detection system compares at least two recorded terrain images from the sheet, thereby directly measuring velocity and direction of the sheet.

Abstract: An improved method for monitoring stack quality in a finisher of a printer includes examining the net displacement of a compiling tray after each set has been ejected. A deviation from the normal increments of displacement for each set triggers a “tray full” condition which alerts a user to empty the tray.

Abstract: An improved sloped stack detection system for a multi-function finisher includes a reflective sensor which suspends the conveying of stapled sets to an output tray when staple build-up in small stapled sets causes the stacked output to become sloped.

Abstract: An improved booklet maker incorporates a movable backstop for compiling incoming sheets and a stapler and creasing module, which is moved to various positions during the booklet making sequence. The moving stapler and creasing function enables the compiling function to occur simultaneously with the stapling and creasing functions. This results in a productivity gain without a footprint increase.

Abstract: In a booklet maker or sheet folder wherein one or more sheets are pushed through a nip formed by a pair of crease rolls, and wherein the crease rolls are driven by gears, a slip clutch is operatively disposed between one of the crease rolls and the gear driving the crease roll. The slip clutch compensates for the abrupt change in frictional coefficient experienced by the crease rolls when one or more sheets enter the nip.

Abstract: Multiple sheet set compiling in a compiler of the seriatim output of printed sheets from a printer with a sheet entry position and a lateral sheet tamping system for laterally tamping the sheets being stacked in the compiler, in which the accumulated stack height of the sheets being compiled is estimated, and in response thereto the height of the top of the lateral sheet tamping system is raised to be maintained above the top of that rising (thicker) stack in the compiler, and lowered for the initial sheets stacking, and the compiler sheet entry position is also automatically raised in proportion to the increasing height of the stack of sheets being compiled in the compiler.