Xerox Corporation

David R Deetz

James M Donohue

Bernard C Fisk

Gerald C VerSchage

Roy H Ogburn

To obtain a substantially uniform print density while printing at high speed with a hammer-type impact printer, the hammer is electromagnetically driven in response to an energizing current which decays with a predetermined time constant from a high initial level toward a set point level which is automatically adjusted for different classes of characters so that the impact energy imparted to the hammer is regulated as a function of the character being printed. To adaptively absorb the shock forces generated by the rebounding hammer, the energizing current for the electromagnetic driver is reduced to a predetermined fraction of the set point level.

Hammer driver controller for impact printers

To enable an automatic typewriter or the like equipped with a hammer-type impact printer to print substantially straight and uniformly dense underscoring lines, provision is made for automatically forming multiple character underscores from a series of overlapping underscore characters. Moreover, to optimize the appearance of the underscoring, provision is made for automatically centering single or multiple character underscores relative to the character or characters which are to be underscored.

Enhanced underscoring methods and means for automatic typewriter and the

To enable an impact printer, employing a daisy wheel print element and a ribbon which is raised to an up or print position from a down or character viewing position, to print without loss of portions of the characters because of incomplete ribbon lift caused by contact between the ribbon and the print wheel, provision is made for enhancement of ribbon lift by controlling the direction of print wheel rotation during ribbon lift.

Means and method for enhancing ribbon lift

A programmable controller is used to control the operation of a xerographic reproducing machine adapted to run in a simplex or duplex mode whereby copies are made on either or both sides of web material fed in a single pass and then cut into individual copy sheets. A control program, comprised of a set of program instructions, enables the controller to generate control signals for actuation of the process devices of the reproducing machine in a timed manner for production of copies as directed by the operator. In response to instructions by the operator concerning copy length, copy numbers, etc., the control program permits the calculation of requisite timing information for control of the machine operating components. The control program permits the operation of the reproducing machine to be responsive to the machine status in control of the machine operating components. The control program includes one or more subroutines for independently operating selected components of the machine to the exclusion of other components to facilitate servicing of the machine.

Programmable controller for controlling reproduction machines

A programmable controller is used to control the operation of a xerographic reproducing machine adapted to run in a simplex or duplex mode whereby copies are made on either or both sides of web material fed in a single pass and then cut into individual copy sheets. A control program, comprised of a set of program instructions, enables the controller to generate control signals for actuation of the process devices of the reproducing machine in a timed manner for production of copies as directed by the operator. In response to instructions by the operator concerning copy length, copy numbers, etc., the control program permits the calculation of requisite timing information for control of the machine operating components. The control program permits the operation of the reproducing machine to concerning copy length, copy numbers, etc., the control program permits the calculation of requisite timing information for control of the machine operating components. The control program permits the operation of the reproducing machine to be responsive to the machine status in control of the machine operating components.

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Dallas, TX, United States of America

David R Deetz