Printronix, Inc.

Other

Norman E Farb

Y Grant Chang

John Stanley Kinley

James Y Chon

Gordon B Barrus

Leo J Emenaker

Robert A Kleist

Glen R Radke

Gerold Holzer

Steven S Hughes

A new high strength steel alloy characterized by having high DC magnetic saturation, ultra high tensile, yield and fatigue strengths that is particularly suited for use as a hammerspring in hammerbanks in impact printers and for other applications where magnetic alloys are used and high mechanical strength is desirable. The alloy is formed of the following composition in weight percent: about 20% to about 35% Co; about 2% to about 6.0% Ni; about 0.0 to about 0.15% C; about 0.75% to about 3% Mo; 0% to about 3.0% Cr; 0% to about 2% Mu; 0% to about 0.02% Si; 0% to about 0.003% P; 0% to about 0.001% S; 0% to about 0.005% 0 &plus;N ;with the balance comprised of Fe. A process for making the alloy includes homogenizing preferably at a temperature of 2150&deg; F. for 24 hours, and solution treating at a temperature in the range of about 1500&deg; F. to about 1700&deg; F. under a vacuum or inert gas protective atmosphere; air-cooling; and precipitation aging at a temperature in the range of about 800&deg; F. to about 1100&deg; F. for about 6 to about 36 hours.

High strength metal alloys with high magnetic saturation induction and method

A line printer with a hammerbank having print hammers with printing tips and a ribbon supported for impact by the tips for printing on media and a metal platen for supporting the media. An elastomer on the metal platen supports the media and has a layer of material harder than the elastomer extending inwardly from its surface which receives the impacts of the hammer tips. The harder material can be particles extending inwardly randomly from the surface of the elastomer of a ceramic having a sphericity exceeding 0.50 up to 35 percent of the thickness of the elastomer, and in the range of 20 microns to 400 microns in size.

Resilient elastomeric line printer platen having outer layer of hard material

A new high strength steel alloy characterized by having high DC magnetic saturation, ultra high tensile, yield and fatigue strengths that is particularly suited for use as a hammerspring in hammerbanks in impact printers and for other applications where magnetic alloys are used and high mechanical strength is desirable. The alloy is formed of the following composition in weight percent: about 20% to about 35% Co; about 2% to about 6.0% Ni; about 0.0 to about 0.15% C; about 0.75% to about 3% Mo; 0% to about 3.0% Cr; 0% to about 2% Mn; 0% to about 0.02% Si; 0% to about 0.003% P; 0% to about 0.001% S; 0% to about 0.005% O.sub.2 +N.sub.2 ; with the balance comprised of Fe. A process for making the alloy includes homogenizing preferably at a temperature of 2150.degree. F. for 24 hours, and solution treating at a temperature in the range of about 1500.degree. F. to about 1700.degree. F. under a vacuum or inert gas protective atmosphere; air-cooling; and precipitation aging at a temperature in the range of about 800.degree. F. to about 1100.degree. F. for about 6 to about 36 hours.

High strength metal alloys with high magnetic saturation induction and

A line printer having a hammerbank for printing on media with print hammers to impact a ribbon to form a dot matrix array having printing tips and permanent magnets for magnetically retaining the hammers. Coils release the hammers by overcoming the magnetism to impact a platen against which the hammer printing tips can strike a ribbon and the underlying media. A cover overlies the hammers having an elongated ridge, and is secured to the hammerbank by threaded members. A print ribbon mask is threadably secured to the cover with openings indexed to openings of the cover to allow the passage of the printing tips.

Line printer hammerbank cover with spaced apart thickened sections

An impact printer and method of printing having a plurality of hammers in side-by-side relationship with pairs of pole pieces in associated relationship with each hammer with a hammer contact end and a distal end removed from the hammer contact. A pair of elongated magnets span the pole pieces at their distal ends and a magnet connection connects the magnets for creating a magnetic circuit through the pole pieces. The pole pieces have reduced adjacent facing areas at their distal ends, and are reduced in cross-section intermediately between their ends. The reduction in area between pole pieces directly reduces the permeance and mutual induction thereby creating greater accuracy of printing by the hammers.

Line printer with reduced magnetic permeance

A process and apparatus for welding a tungsten carbide printing tip of a dot matrix printer to a hammerspring by holding the hammerspring in a fixture with a first electrode in adjacent relationship thereto and a second electrode in adjacent relationship to a tungsten carbide printing tip having cobalt and forcing said tungsten carbide printing tip into adjacent relationship with said hammerspring while causing cobalt in said tungsten carbide printing tip to be welded to said hammerspring through a welding current between said first and second electrodes.

Tungsten carbide welded printer tips

The specification describes a low reluctance magnetic circuit for a dot matrix line printer for retaining hammersprings by the magnetic circuit having pairs of pole pieces formed of magnetically conductive sheets having a space for receipt of a permanent magnet. A coil is wrapped around a portion of each of the pole pieces between the magnet and the ends to provide a reverse magnetic field to the magnetic field provided by the permanent magnet. A magnetic shunt is established between the pole pieces to provide a greater magnetic effect. The pole pieces are sized and plated at the ends, with a spaced wear bar between them to provide improved performance and longer wear.

Printer hammerbank with low reluctance magnetics

The specification sets forth a hammerspring for a dot matrix printer having a plurality of such hammersprings spaced along a hammerbank with permanent magnetics to draw said hammersprings into a retracted and uniformly stressed mode through a spring portion which are released by overcoming the magnetic retention, the hammerspring formed with a base portion connected to the hammerbank with a spring portion extending from said base portion having a decreasing transverse cross sectional area extending to an enlarged end portion for improved magnetic retention against said permanent magnets.

Printer hammerspring

An improved hammerbank in a dot matrix line printer has two different sets of staggered apertures therein along the length thereof for drawing pressurized air at the outside of the hammerbank therein to provide turbulent, high velocity cooling air in the region below the magnetic coils of the magnetic hammer actuators. The cooling air is confined to passage over the magnetic coils by enlarged flanges on the coil bobbins which form an air dam. The air dam discourages escape of the cooling air through spaces between the hammer springs. Magnetic interaction between adjacent magnetic hammer actuators is minimized due to the absence of common magnetic materials extending therebetween, except for the permanent magnets which hold the hammer springs in the retracted position. The permanent magnets are common to a plurality of the magnetic hammer actuators and by physically extending therebetween serve to prevent substantial leakage flux from occurring. The hammerbank is mounted for reciprocating motion by a single, intergrally formed, hollow shaft which extends through the entire length of the hammerbank and beyond the opposite ends thereof. The hammer springs are mounted by screws driven into endless screw holes which terminate at the cooling apertures within the hammerbank so as to accommodate relatively long screws and at the same time expel debris that might otherwise accumulate within the screw holes. The upper portions of a cover assembly at the front of the hammerbank are held in fixed relation by magnetic clip assemblies mounted thereon and having permanent magnets attached thereto in a manner which permits precision grinding of the clip assemblies.

Printer having improved hammerbank airflow

In a dot matrix line printer in which a plurality of hammer springs mounted along the length of an elongated reciprocating hammerbank are selectively released or fired to impact dot printing impact tips mounted thereon against a print paper through a length of ink ribbon to print dots, the wear that would otherwise occur each time one of the hammer springs rebounds back into contact with a pair of pole pieces against which the hammer spring resides when in its retracted position is greatly minimized by chromium masses plated on the tip of the hammer spring and on the tips of the pole pieces. Chromium platings on each hammer spring are confined to the end of the spring and comprise either a pair of masses adjacent the different pole tips or a single mass encompassing both pole tips. The chromium masses are of convex contour and of hexavalent chromium composition to provide the masses with hard and smooth surfaces that slide over and do not abrade one another upon impacting.

Impact printer having wear-resistant platings on hammer springs and pole

In a print hammer mechanism in which a thin, flat hammer spring is mounted at a fixed end thereof to a magnetic structure which includes a permanent magnet and a pole piece having a pole tip facing the opposite free end of the hammer spring on a side of the hammer spring opposite an impact printing tip, a pivot fulcrum is formed by an impact arrangement which faces an intermediate portion of the hammer spring between the fixed and free ends thereof. The permanent magnet normally pulls the hammer spring into a retract position in which the spring impacts and resides against the impact structure with the free end of the spring forming an air gap with the pole tip. Energization of a coil surrounding the pole piece releases the hammer spring from the retract position, enabling the spring to return toward a neutral position and then impact a printable medium such as a print paper-ink ribbon combination, following which the magnetic attraction of the permanent magnet returns the hammer spring to the retract position in which it strikes the impact structure and remains in the retract position pending the next energization of the coil. The location of the impact arrangement is such as to greatly minimize wear at its interface with the hammer spring while at the same time enhancing the release characteristics of the hammer spring. In a preferred embodiment the impact structure is formed by a secondary pole piece extending in parallel, spaced-apart relation along a portion of the length of the hammer spring from the fixed end thereof and terminating in a pole tip covered with a thin layer of Kapton.

Print hammer mechanism having intermediate pivot fulcrum

In a printer in which a shuttle and a counterbalancing mass are driven in opposing reciprocating fashion by a rotating, generally oval-shaped cam, the cam followers which couple the shuttle and the counterbalancing mass to the cam are castered to prevent skewing of the cam followers relative to the cam. Each of the cam followers is disposed between and rotatably mounted on a pair of opposite arms extending outwardly from a generally planar base of a castered yoke assembly, the planar base being pivotally coupled to a supporting member therefor which is either coupled to the shuttle or forms a part of the counterbalancing mass. In a first embodiment the pair of opposite arms extend from the planar base toward the cam so as to dispose the cam follower between the pivotal mount of the yoke assembly and the cam. In a second embodiment the pair of opposite arms extend from the planar base in a direction away from the cam so as to dispose the pivot point of the yoke assembly between the axis of rotation of the cam follower and the cam.

Printer shuttle drive having castered cam followers

In an impact printer system in which various hammer springs mounted in side-by-side relation along a reciprocating hammer bank are selectively released to cause an impact tip mounted at the upper end of the hammer spring to impact a paper or other printable medium, the hammer springs are divided into two different groups and the release of the hammer springs in the different groups is staggered. Alternate ones of the hammer springs comprise a first group of hammer springs which are selectively released at the beginning of each of a succession of cycles as the hammer bank sweeps across the printable medium. The remaining ones of the hammer springs comprise a second group and are releaseable at a midway point through each cycle. When any given hammer spring is released, an electro-mechanical mutual inductance effect is released in which the adjacent hammer springs and associated pole pins provide a beneficial improvement in the mutual inductance, and the current required to release each hammer spring and the total power required to operate the hammer bank are significantly reduced. To compensate for the staggered release of the hammer springs, the hammer springs are located to provide other than uniform spacing between the impact tips. The impact tip on each hammer is spaced a first fixed distance from the impact tip on the adjacent hammer on one side thereof and a second fixed distance from an impact tip on an adjacent hammer on the other side thereof. The difference between the first and second fixed distances is equal to the distance that the hammer bank travels relative to the printable medium during each of the succession of cycles.

Printing system having staggered hammer release

A handle for a vibratory massage unit of the type including an applicator head which translates laterally in a circular motion upon rotation of a drive shaft. The handle solves the problem of excessive vibration by providing static and dynamic balancing of the moving parts so as to prevent operator fatigue. A pair of offset bearings provide the transition from pure rotational motion to translational motion and an oppositely offset counterweight provides the static and dynamic balancing.

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Villa Park, CA, United States of America

Norman E Farb