US2656570A - Plastic matrix for printing resistors - Google Patents

Description

1953 E. F. HARMON ETAL 2,656,570

PLASTIC MATRIX FOR PRINTING RESISTORS Filed Nov. 15, 1951 i 9 I 6 Q9 2/ I I l 2026 29 2; hi as/1(E15Z4h J/ 20 as i 35 32 2 35' INVENTORi.

.26. 2t 7 2/ 20 Eg I1 Hal -mun :51 I 5- By 1 1 J. Fran'K'l-m.

HH- cruel-[ Patented Oct. 27, 1953 PLASTIC MATRIX FOR PRINTING RESISTORS Elise F. Harmon and Philip J. Franklin, Washington, D. 0., assignors to the United States of America as represented by the Secretary of the Army Application November 15, 1951, Serial No. 256,584

(Granted under Title 35, U. S. Code (1952),

sec. 266) 2 Claims.

This invention relates to a matrix for applying pigment to a surface and more particularly to a plastic matrix for use in printing resistors, circuits and the like on plastic, ceramic, glass or similar non-porous materials.

In the production of printed circuits, particularly resistors, it is desirable to imprint a carefully metered amount of resistive material in a predetermined area and position on a plate of non-porous insulating material. Many methods of printing have been used in attempts to produce a resistor within allowable tolerances, but none have been able to produce the desired quantitative control of material.

The apparatus shown in the U. S. Patent No. 2,302,096, has been used successfully to deposit measured amounts of ink on paper and similar materials which are of sufficient resilience to conform to the steel matrix of the apparatus, and which permit the bleed-off of air and solvent due to the porosity of the material. However, the matrix of this apparatus will not successfully print resistors on ceramic or similar material because the matrix will not conform to the surface of the ceramic, resulting in resistive elements of non-uniform cross-section and length.

An object of the invention is an improved matrix which will print resistors within allowable tolerances.

Another object of the invention is a matrix and ink feeding means therefore, adaptable to the printing apparatus of the type disclosed in the above referred to patent.

A further object of the invention is a matrix for printing resistor elements and the like on ceramic and similar non-porous, hard surface materials.

The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of any royalty thereon.

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from the following description and accompanying drawings in which:

Figure 1 is a perspective view of the matrix of the invention.

Figure 2 is a top view of the inking plate and matrix assembly.

Figure 3 is a bottom view of the inking plate and matrix assembly.

Figure 4 is an enlarged sectional view taken along line 4-4 of Figure 3.

Figure 5 is a sectional view, showing the in- 2 vention assembled to the apparatus illustrated in Figure 12 of the U. S. Patent No. 2,302,096. The section through the invention is taken along line 5--5 of Figure 2.

Referring to the drawings, 1 represents the cup-shaped matrix made of polyethylene, teflon or similar non-wetting material which is relatively firm, but sufiiciently resilient to conform to such surface irregularities as are normally encountered in ceramics and like materials. The matrix is provided with a horizontal flange 2 and vertical walls 3. The outside bottom surface l has formed therein recesses comprising ink wells 5 of definite shape and dimensions which, as shown, will print resistors within allowable tolerances upon materials having a hard and non-porous surface. Surrounding each of the inkwells is a knife-like vertical projection 1 of the bottom surface 4 which provides an airtight seal around each of the inkwells when the matrix and plate to be printed are brought together under pressure. Each inkwell is provided with inlet port 8 to permit ink under controlled pressure to be fed to the well and an outlet port 9 to bleed off the air and excess ink which would otherwise be trapped therein. It is apparent that by varying any or all of the dimensions of the inkwells, printed resistors of desired values may be obtained.

A steel printing plate ID for holding and feeding ink to the matrix I has a rectangular groove 2| cut therein from the bottom surface 29 of the plate so as to form a boss 21w bounded by the groove and upon which is placed the matrix with its flange 2 resting on the bottom of the groove. A retaining ring 22, positioned in the groove by means of dowels 23, is fastened therein by screws 24 and bears against the flange 2 and walls 3 of the matrix, maintaining the matrix in engagement with the boss 2m. The top surface We of the plate is provided with a channel 25 having two parallel legs 26--21. Perforations 2B spaced longitudinally of the legs 262'l extend from the legs 262l through the boss 2Ia in alignment and communication with ports 8 of the matrix. A second channel 29, also in the top surface of the plate, has two parallel legs 30--3| spaced from but substantially embracing the legs 26-21 and are in communication with the outlet ports 9 through means of perforations 32 which extend from the legs through the boss in alignment with the outlet ports.

In operation, when the ceramic plate to be printed and the matrix are in contact, a measured quantity of ink is fed under pressure to the channel 25 and flows therefrom through perforations 28 and inlet ports 8 to fill the inkwells 6. Any excess ink. and trapped air, pass through the ports 9 and perforations 30 to the legs of channel '29.

In Figure there is shown the matrix and printing plate of the invention assembled whites;

II of the apparatus of the referred to patent bymeans of screws 33 in the recessed perforations 35 in the printing plate 10., The invention, thus, involves a matrix and methodto adapt the aforementioned apparatus to printing on non-porous materials. In the adaptation, a measured amount of pigment under pressure flows through the. valve I4 and clock ll of the appartus to channel 25 of plate It) whereupon the inkwells 6 of the matrix are filled through ports it and; perforations 28. The excess air and pigment are bled from the inkwells 6 through ports 9 and perforations 32 to channel 29 from whence they are bled through a perforation 38 in the block to a valve system not shown.

It will be apparent that the embodiment shown is only exemplary and that various, modifications can be made in construction and arrangement within, the scope of the invention as defined in the appended claims.

We claim:

1. The combination of a resilient matrix and pigment, feeding means therefor for printing precision resistors on non-porous materials, comprising a cup-shaped matrix having; a flange surrounding the opening thereof, resistor forming recesses in theouter bottom surfaceof the matrix,

resilient members formed on said outer bottom surface and surrounding the opening of each recess, inlet and outlet ports in the bottom of said matrix communicating the cavity thereof with said recesses, a steel plate provided with a. rectangular groove in its top face forming a boss therein upon which is fitted the said matrix with its inner cottom surface engaging the surface of said boss and the flange engaging thebottom of said groove, a retaining ring in said rectangular groove for keeping the matrix and platein positive engagement, a first channel inthe; bottom face of the plate for receiving a measured quantity of resistor forming pigment underpressure, perforations in said boss; extending from said first channel to said inlet ports to permit the pigment to enter and fill said resistor forming recesses, 21 second channel in the bottom face and: associated perforations in said boss connecting said second channel and said outlet ports for relieving the resistor forming recesses of excessiv amounts of pigment and air entrapped therein.

2. The combination of a resilient matrix and pigment feeding means therefor for printing precision resistors on non-porous materials comprising; a. substantially cup-shaped matrix having flange surrounding the opening thereof, precision resistor forming recesses in the outer bottomsurface of the matrix, resilient projections of said outer bottom. surface having a triangular cross section and surrounding the opening of each of said recesses, each of said resilient projectionsn adapted to compress upon contact with said non.,-porous material so as to substantially form projections of the vertical walls of each of said recesses, inlet and outlet ports in each of said recesses, a steel plate having a rectangular groove in its top face forming a boss therein upon which, is fitted the said matrix with the inner bottom. Surface there-of engaging the surface of said boss, thei'lange of said matrix engaging the bottom of said groove, a retaining ring in said rectangular groove for keeping the matrix and plate, in, positive engagement, a first. channel. in the bottom face of the plate for receiving a measured quantity. of resistor forming pigment under pressure, perforationsin said boss extending from said first channel to said, inletports. providing means.

for the pigment to enter and fill said resistor formingw recesses, a second channel in the bottom face, and associated perforations, in said boss connecting said second channel and said outlet ports for relieving theresistor forming, recesses of excessive amounts of pigment and, air entrapped. therein.

ELISE, E. HARMON.

PHILIP J FRANKLIN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,849,571 Gurnee etal Mar. 15, 1932 2,152,738 J'efiery Apr. 4, 1935' 2,256,769: Amrine Sept. 23, 1941 2,266,831 Tegarty Dec. 23, 1,941 2,302,096 Battey Nov. 17, 1942 FOREIGN PATENTS Number Country Date,

605,978 Great Britain Aug; 4, 1948:

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