Xerox Corporation

Andrew Gabor

John C Dunfield

Richard G Crystal

George W Bowers

Enrique J Klein

Brian E Jagger

Robert A Ragen

Ivor Weller

Kenneth W Cocksedge

Michiel Frankhuizen

Keith L Gnutzman

Michael G Demeny

A serial impact printer and including a single cam member for properly establishing and maintaining the throat gap distance between a character imprinting surface and the platen at a print point and for raising and lowering a selected ribbon, of a composite marking correcting ribbon pack assembly, to and from the print point. A short throat gap distance is needed for commercially acceptable printing speeds in this hammer mass printer, and is needed for high quality printing; conversely, a long throat gap distance is needed for print point visibility at all other times. The cam member has plural camming surfaces which coordinate ribbon position with throat gap distance.

Apparatus and method for controlling the positioning of marking elements

An impact mechanism for an improved serial impact printer for delivering a printing force to drive a character element against a platen by means of a print tip movable toward and away from the platen. The print tip is supported upon a carriage mounted upon the printer for reciprocating movement in a path substantially parallel to the axis of the platen. The impact mechanism includes a bail bar extending substantially across the printer and mounted for rocking movement toward and away from the platen, its axis of rocking being substantially parallel to the axis of the platen. A prime mover is connected to the bail bar for imparting controlled rocking movement thereto. The print tip and the bail bar are interconnected so as to move the print tip toward and away from the platen as the bail bar is rocked.

Impact mechanism for quiet impact printer

A serial impact printer including a novel hammer mechanism for applying a printing force against a character element to drive it in sequence against a marking medium, a mark receiving support, such as a sheet of paper, and the print line on a platen. The hammer mechanism delivers its impact force against a character element along a line forming an angle with a line normal to the surface of the platen at the point of contact of the character element with the platen. This arrangement enhances the ink release of single strike ribbons and multi-part carbon forms. By urging the hammer mechanism against the character element for an extended dwell time of at least 1 millisecond, which is substantially greater than that in conventional printers, the ink release of multi-strike ribbons, fabric ribbons and correctable ribbonsd may also be enhanced. By incorporating both the oblique impact and the extended dwell, the ink release characteristics of all conventional ribbons and multi-part forms will be enhanced.

Impact printer with application of oblique print force

An improved serial impact printer designed to substantially reduce impact noise generation during the printing operation. The printer includes a print tip exhibiting high effective mass relatively movable with respect to a deformable platen, with a print element, a marking ribbon and an image receptor sheet interposed between the print tip and the platen which are urged together during a controlled contact period of extended length.

Quiet impact printer

An impacting element for an impact printer having a platen, selectable character elements and means for driving the impacting element to impart a printing force to a selected character element, to drive it against said platen for a contact period, the impacting element including a sensor thereon for generating a signal indicative of the initiation of the contact period.

Print tip contact sensor for quiet impact printer

An improved serial impact printer designed to substantially reduce impact noise generation during the printing operation. The printer includes a print tip relatively movable with respect to a deformable platen, with a print element, a marking ribbon and an image receptor sheet interposed between the print tip and the platen which are urged together during a controlled contact period. Movement is subject to control by a kinetic drive mechanism which applies a first force for moving the print tip relative to the platen, prior to the initiation of the contact period, for closing the gap therebetween and then applies a second force for accelerating the print tip relative to the platen, subsequent to the initiation of the contact period, for causing the print tip to deform the platen.

Apparatus is disclosed for controlling the movement of a movable element to bring said movable element to rest at a desired stopping position. The apparatus comprises a multi-phase drive motor having a drive shaft coupled to the movable element for driving same, a plurality of electrically conductive coils mounted in position-displaced relationship about the shaft, and means coupled to the drive shaft and responsive to the selective energization of the coils by respective motor drive signals for causing the corresponding rotation of the drive shaft and movement of the movable element. A sensor is coupled to the drive shaft and is responsive to the rotation thereof for generating an electrical signal containing information indicative of the direction, speed and distance of movement of said movable element. Further, means are included for detecting from the distance information indicated by the electrical signal whether the movable element is within a predetermined distance of the desired stopping position. When it is, a controller controls the levels of the motor drive signals in dependence upon the direction information indicated by the electrical signal.

Motion damping apparatus

Apparatus is disclosed which is responsive to the movement of a movable element for generating a plurality of electrically phase-displaced signals containing information indicative of the direction, speed and distance of movement of said movable element. The apparatus comprises a plurality of position-displaced electrically conductive coils and a permanent magnet mounted adjacent each of said coils for producing a path of normally substantially constant magnetic flux adjacent each of said coils. A flux varying device is coupled to the movable element and is responsive to the movement of the movable element for varying the level of the magnetic flux adjacent each of the coils in dependence upon the direction, speed and distance of movement of the movable element, whereby the resultant electromotive force induced in each of the coils defines the plurality of electrically phase-displaced signals.

Motion sensing apparatus

Apparatus is disclosed for controlling the movement of a movable element between an initial starting position and a final stopping position. The apparatus comprises drive means coupled to the movable element and responsive to motor drive signals for moving the movable element along a predefined path between said starting and stopping positions; and first generating means for generating a first command velocity signal having a first state when the actual velocity of the movable element exceeds a predetermined value and a second state when the actual velocity of the movable element is less than the predetermined value. A controller periodically senses the state of the first command velocity signal when the movable element has less than a first predetermined distance and greater than a second predetermined distance to travel to the final stopping position, and controls the levels of the motor drive signals to cause (a) the acceleration of the movable element by the drive means when the first command velocity signal is sensed at its first state, and (b) the deceleration of the movable element by the drive means when the first command velocity signal is sensed at its second state.

Closed loop velocity control system for a movable element

Apparatus is disclosed which is responsive to the movement of a movable element for generating a plurality of electrically phase-displaced signals containing information indicative of the direction, speed and distance of movement of the movable element. The apparatus comprises a plurality of position-displaced electrically conductive coils; a permanent magnet mounted adjacent each of the coils for producing a path of normally substantially constant magnetic flux adjacent each of the coils; and a flux varying device coupled to the movable element and responsive to the movement of the movable element for varying the level of the magnetic flux adjacent each of the coils in dependence upon the direction, speed and distance of movement of the movable element, whereby the resultant electromotive force induced in each of the coils defines the plurality of electrically phase-displaced signals. The flux varying device includes a rotor having a plurality of spaced teeth about the periphery thereof, the rotor being coupled to the movable element such that the rotor will rotate in a direction and at a speed corresponding to the direction and speed of movement of the movable element. The flux varying device also includes a plurality of pole pieces about which the coils are respectively wrapped, the pole pieces being mounted adjacent the path of travel of the rotor teeth such that a first gap of predetermined longitudinal extent is defined between the path of travel and each of the pole pieces, the longitudinal extent being perpendicular to the axis of rotation of said rotor.

A print hammer assembly is disclosed comprising a support structure having a plunger at a first location thereon, and means for movably mounting the support structure with its plunger adjacent an electromagnetic actuator capable of being selectively energized such that, when the actuator is energized, the resultant magnetic field acting upon the plunger will cause the plunger and thus the support structure to travel along predefined paths and predetermined speeds. A hammer element is coupled to the support structure at a second location thereon, and means coupled to the hammer element causes the hammer element to impact an adjacent platen or interposed print element against an adjacent platen more than once during travel of the pole piece along its predefined path. The means for causing includes means for altering the location of maximum impact force of the hammer element following initial impact thereof against the platen or the interposed print element against the platen.

Print hammer assembly with multi-location impacts

A print hammer assembly is disclosed comprising a support structure having a plunger at a first location thereon, and means for movably mounting the support structure with its plunger adjacent an electromagnetic actuator capable of being selectively energized such that, when the actuator is energized, the resultant magnetic field acting upon the pole plunger will cause the plunger and thus the support structure to travel along predefined paths at predetermined speeds. A hammer element is coupled to the support structure at a second location thereon, and means coupled to the hammer element causes the hammer element to impact an adjacent platen or an interposed print element against an adjacent platen more than once during travel of the pole piece along its predefined path. The means for causing includes a pair of adjacent, substantially identical, normally planar spring members that lie in intersecting planes, the spring members cooperating with the support structure to alter the location of maximum impact force of the hammer element against the platen or the print element against the platen for each succeeding impact following the initial impact during travel of the plunger along its predefined path in response to a single energization of the actuator.

Print hammer assembly with amplified multi-location impacts

Method and apparatus for accurately positioning a blank angular position transducer element for boring at its center. A relatively high frequency carrier signal is applied to the blank transducer element to be bored and is thereby induced in a master rotor element which is rotated at a constant speed in an operative relationship with the blank. The rotor is made deliberately eccentric with respect to its axis of rotation, and the induced signal contains a carrier signal, a component indicative of relative angular position, and a once-per-revolution eccentricity error component, if the blank element is also eccentric with respect to the axis of rotation. Error detection circuitry isolates the once-per-revolution eccentricity error component, and resolution circuitry resolves it into x and y directions for application to error display devices, or to actuators connected to move the blank transducer element automatically until the x and y components are both zero. The blank element can then be bored by a tool movable along and rotable about the axis of rotation.

Electrical centering and boring system for transducers

A high-speed printer with a printing wheel with the individual type elements supported by radially extending spokes. Separate servo systems provide intermittent movement for the printing wheel and the carriage carrying the printing wheel.

Growing community of inventors

Alamo, CA, United States of America

Andrew Gabor