Xerox Corporation

John R Leicht

Gordon Sohl

Donald L Ort

Charles L Bradford

James G Hume

Alfred G Osterlund

John R Masters

A sheet feed device for sequentially selecting and feeding sheets of paper from one or more trays or magazines mounted upon a printer and delivering them to the platen of the printer. The device includes one or more selector latch mechanisms, one associated with each tray, whose movement is controlled by the platen rotation and which, in turn, controls the rotation of sheet feed rollers associated with the trays, in response to a specific sequence of forward and reverse angular platen movements.

Selector latch for a sheet feeder

A method of calibrating a scanning carriage drop-on-demand ink jet ejector wherein the ejector is traversed past a droplet detection light beam while droplets are ejected. By knowing the position of the ejector and relating it to the amount of light blocked by droplets, horizontal errors in drop position can be detected. Similarly, by measuring the amount of time elapsing between droplet ejection and droplet detection, the velocity of the droplets can be determined. Corrections can be made by adjusting the time of ejection and/or the drive pulse amplitude and/or width.

Automatic calibration of drop-on-demand ink jet ejector

For use in an electronic printing system having a serial impact printer, apparatus is provided to accurately control the velocity of the print hammer during printing and provide accurately controlled impact energy, which is proportional to the character face area. The apparatus includes a servo feedback system where the primary driver for the print hammer is a moving coil in a magnetic field, and the velocity sensing required for the servo feedback loop is the back emf in the moving coil with the back emf being proportional to the hammer velocity.

Moving coil, multiple energy print hammer system including a closed loop

A limited motion actuator which utilizes a moving permanent magnet as an armature. The drive is provided by the simultaneous repulsion and attraction of the movable permanent magnet within stationary coils. The magnetic circuit is formed to allow one pole of the armature to be simultaneously repelled from the coil of like polarity and attracted to the pole of opposite polarity. The preferred magnetic circuit configuration consists of two poles and a magnetic return path, which forms two additional poles. The movable permanent magnetic armature is always located within the regions of the coil poles thus allowing accurate control of the driving forces in both forward and reverse directions over the complete armature cycle.

Growing community of inventors

Bedford, TX, United States of America

John R Leicht