Xerox Corporation

Robert A Ragen

Carl E Herendeen

Andrew Gabor

Brian E Jagger

Ivor Weller

Michiel Frankhuizen

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

A novel rotary printing device, such as a daisy-type printwheel, for use in an impact printer, having identifying means thereon. In one form, plural protrusions, extending axially outwardly from the printing device, are provided and the angle between the protrusions serves the dual function of identifying the print element characteristics and identifying the reference position of the printing device for 'arming' the printer with the information. In another form, a single protrusion is provided solely for identifying the reference position. A method and apparatus for in situ identification of the novel rotary printing device also forms a part of the instant invention.

Rotary printing device with identifying means and method and apparatus

Apparatus is disclosed for controlling the movement of a movable element to bring the 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, four 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 said drive shaft and movement of said 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 said 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 such that the motor and thus the movable element are brought to a final stop with only a single one of the motor drive signals and thus corresponding single motor coil on. The controller selectively turns on and off or reverses either the two coils displaced counterclockwise of the single motor coil about the shaft or the two coils displaced clockwise of the single motor coil about the shaft in dependence upon the direction information indicated by the electrical signal.

Electronic damping 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 the starting and stopping positions; first benerating means coupled to the drive means for generating an actual velocity signal indicative of the actual speed of movement of the movable element; second generating responsive to a position signal indicative of the distance remaining to travel by the movable element toward the desired stopping position for generating first and second command velocity signals respectively indicative of the minimum and maximum desired velocity levels for such particular distance remaining to travel; and control means coupled to the first and second generating means and responsive to the position signal for comparing the actual velocity signal with each of the first and second command velocity signals when the value of the position signal indicates the movable element has greater than a predetermined distance to travel, and for issuing the motor drive signals in response to such comparison for application to the drive means to cause (a) the acceleration of the movable element by the drive means when the comparison indicates the actual velocity of the movable element is less than the minimum desired velocity, (b) the coasting of the movable element when the comparison indicates the actual velocity of the movable element is more than the minimum desired velocity and less than the maximum desired velocity, and (c) the deceleration of the movable element by the drive means when the comparison indicates the actual velocity of the movable element exceeds the maximum desired velocity.

Motion control apparatus

In a printer including a record material movable past a printing station, and a print assembly capable of printing a line of characters in dot matrix format upon relative movement of the print assembly and the record material in a first direction, a method and apparatus is disclosed for printing the line of characters. In accordance with such method and apparatus, the print assembly and record material are first moved relative to one another in the first direction at a first predetermined speed. Then, the print assembly is activated to print a first predetermined number of dots of the dot matrix pattern defining each character in the line. This is followed by moving the print assembly relative to the record material a predetermined amount in a second direction perpendicular to the first direction, and effecting relative movement of the print assembly and the record material in a third direction opposite the first direction. Then, relative movement is effected between the print assembly and the record material in the first direction again, but at a second predetermined speed. This is followed by activating the print assembly to print a second predetermined number of dots of the dot matrix pattern defining each character in the line.

Multi-pass matrix printing

Apparatus for energizing a selected one or more of a plurality of actuation devices in order to cause a printing element associated with each selected actuation device to strike an adjacent recording medium. The apparatus comprises memory means responsive to a predetermined address signal for supplying a plurality of data bits and a conversion bit together identifying those actuation devices selected for energization, a plurality of switches respectively coupled to the plurality of actuation devices, each switch capable of energizing its respective actuation device in response to receipt of a data bit of a first state, means coupled to the memory means and to first and second predetermined ones of the switches and being responsive to the conversion bit being of a first state for supplying a predetermined data bit to the first predetermined switch and responsive to the conversion bit being of a second state for supplying the predetermined data bit to the second predetermined switch, and means coupled to the memory means and to other ones of the switches for respectively supplying other ones of the data bits to such other ones of the switches.

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Hayward, CA, United States of America

Robert A Ragen