US3484318A - Method of concurrently producing visible and magnetizable indicia - Google Patents

Description

3,484,318 VISIBLE AND /N|//V7'0/?$. FREDERICK R. NEUFELD MERLE P. PRATER ATTORNEY F. R. NEUF'ELD ET AL CONCURRENTLY PRODUCING MAGNETIZABLE INDICIA Filed June 23 1966 Dec. 16, 1969 METHOD 0F G 3 4 F mm I F F United States Patent 3,484,318 METHOD OF CONCURRENTLY PRODUCING VISIBLE AND MAGNETIZABLE INDICIA Frederick R. Neufeld and Merle P. Prater, Vestal, N.Y.,

assignors to International Business Machines Corporation, Armonk, N.Y., a corporation of New York Filed June 23, 1966, Ser. No. 559,954 Int. Cl. B31f 7/00; B41m /00 US. Cl. 156220 3 Claims ABSTRACT OF THE DISCLOSURE A porous, coalescible polymer material film with a homogeneous dispersion of magnetizable particles is applied to the back side of an embossable non-magnetizable substrate, such as paper. Impacting the paper with a type slug will produce a human readable character on the paper and concurrently, by embossing the paper, compact the particles toward a hard platen to a degree Where they will produce a magnetic character corresponding in configuration to a mirror image of the human readable char acter. This magnetic character will develop a signal level significantly higher than the non-impacted areas when moved relative to and sensed by a magnetic transducer adjacent the exposed and continuously smooth side of the film.

This invention relates generally to a method of producing magnetizable bits or characters which are visible and magnetically detectable.

Generally stated it is an object of this invention to provide an improved method for producing visible magnetizable markings without requiring the use of an external source such as a Magnetic Ink Character Recognition (MICR) ribbon.

More specifically it is an object of this invention to provide for an opaque, porous and coalescible semi-cured plastic emulsion film material impregnated with a magnetizable material which, when impacted by a type member, produces a visible area in which the film clears, and in which the material of the film is compressed so that the concentration of magnetizable particles is increased sufficiently to provide a mark which is easily detectable by a read head when magnetized.

Another object of the invention is to provide for an opaque, porous and coalescible film impregnated with iron oxide particles to provide a visible and magnetically detectable mark when impacted by or against a character bearing element, as in a printer or the like.

Yet another object of this invention is to provide for an opaque, porous and coalescible polymer film homogeneously impregnated with particles of a magnetizable material, and for impacting the film to provide visible markings thereon having a concentration of magnetizable particles in the impacted area which may be magnetized and readily detected by a magnetic read head or the like.

It is also an important object of this invention to provide for coating an opaque, porous and coalescible poly mer film with a high density coating of a magnetizable material and impacting the magnetizable material side of the film to force the magnetizable particles into the film so as to produce an embossing or compacting of the magnetizable material into the opaque, porous and coalescible film, such that it can be readily detected by a magnetic read head from the rear surface of the opaque, porous and coalescible film after it has been subjected to a magnetic field.

In practicing the invention in accordance with a preferred embodiment thereof, an opaque, porous and coalescible film material comprising, by way of example, an open cell structure polymer film of polyacrylonitrile,

3,484,318 Patented Dec. 16, 1969 is homogeneously impregnated with particles of magnetic iron oxide having a concentration on the order of 10 percent, by introducing the iron oxide with the polymer particles in the initial stages of manufacture. When such a film, either separately or bonded to a layer of paper or other similar embossable substrate, is impacted such as by printing thereon by means of an electric typewriter, the printed or impacted area becomes visible, and the iron oxide dispersion is concentrated sufliciently by the impacting to produce oxide concentrations which when magnetized are readily detected by a suitable transducer or read head on the side of the film opposite from where the material is impacted.

The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawings.

In the drawings:

FIGURE 1 is a sectional view in part of an impregnated opaque, porous and coalescible film bonded to a sheet of paper in accordance with one embodiment of the invention;

FIGURE 2 is the sectional view of the embodiment shown in FIGURE 1 illustrating the impacting effect of a type slug or the like on the impregnated film;

FIGURE 3 is the same sectional view as in FIGURE 2 illustrating the detection of the magnetic character or bit by a read head;

FIGURE 4 is the same sectional view as in FIGURE 2 showing the relative effect of a spurious scratch or the like detected by the read head;

FIGURE 5 is a partial cross-sectional view illustrating another embodiment of the invention in which the opaque, porous and coalescible film is provided with a magnetizable coating and bonded to a layer of paper or the like;

FIGURE 6 is the cross-sectional view of FIGURE 5 showing the effects of impacting the coated film by a type slug;

FIGURE 7 is the same crosssectional view as in FIG- URE 6 showing the impacted area being detected by a magnetic read head; and

FIGURE 8 is the same cross-sectional view as in FIG- URE 6 showing the relative efiects that a scratch has on the read head.

Referring to FIGURE 1 of the drawings, it will be seen that a film 10 of an opaque, porous and coalescible film material is homogeneously impregnated with magnetizable material represented by the dots 12 in the film 10 and is secured to a sheet of paper or the like 14, being secured thereto by means of any suitable adhesive, for example, Eastman 910, Duco, Elmers Glue or other suitable polymeric adhesive.

The opaque, porous and coalescible film material may be of the type described in Patent No. 2,846,727 which issued on Aug. 12, 1958, to M. F. Bechtold and which described a number of useful aqueous dispersions of polymers suitable for use in practicing the present invention. The opaque, porous and coalescible film is in accordance with one embodiment homogeneously impregnated with a magnetizable material such as iron oxide which may be added to the aqueous polymer dispersion in the initial step of manufacture. The iron oxide may be added in an amount on the order of 10 percent by weight and may comprise particle sizes on the order of .3 to .4 micron. If desired black ferrosoferric iron oxide may also be used which is acicular in form, having needle-shaped particles on the order of .55 by .08 micron. This impregnated material can be fused or laminated to paper, plastic material or any number of other suitable substrates.

When the laminated article is subjected to mechanical impact by an impact system such as a typewriter or printer, the impact of the type slug embosses the paper 14 and produces a compressing of the opaque, porous and coalescible film in the area of impact 16 when the film is backed up by a hard platen 11 as shown in FIGURE 2. Upon impact the film coalesces and the concentration of magnetic particles homogeneously distributed throughout the film can in the compressed area be increased on the order of five times by compressing the film to approximately 20 percent of it original thickness. When such impacting is done against a hard platen such as that of a typewriter or the like, and the opaque, porous and coalescible material is located adjacent to the platen, a high concentration of the magnetic particles is forced to the exposed surface area of the film adjacent the platen. This occurs as the paper 14 is embossed by the type slug 15 and in turn compacts and coalesces the film from its inside surface. The surface concentration of magnetic particles forms in the impacted area a visible contrasting numerical or alphabetical character which is easily readable, the film in the impacted area clearing the magnetic material showing up as a relatively dark area in contrast with the normally light color of the non-impacted portions of the film.

As a magnetic read head is moved past the opaque, porous and coalescible film on the side which was adjacent the platen 11, a difference in magnetic signals between the coalesced and non-coalesced areas may be readily detected after the film has been subjected to a magnetic field. The crowding of the magnetic particles toward the exposed film surface causes a greater signal strength proportionally than the simple degree of compression would indicate, because of the decrease in the signal produced by remote magnetic particles, through the inverse square law effect. If the matrix is magnetized either before or after impacting, the signal to non-signal ratio is very high.

Any spurious compression of the opaque, porous and coalescible film from the film side of the laminate would separate the magnetic material from the read head by some air gap, which in pre-magnetized materials would decrease any signal because of the inverse square law effect as may be seen by referring to FIGURE 4. The film is provided with a reasonable degree of protection from being accidentally marked on the paper side, except by highly deliberate impact such as produced by a type slug or the like, so that the chances of spurious marking of the laminate are relatively low.

Referring to FIGURE 5 it will be seen that in another embodiment of the invention the opaque, porous and coalescible film may be coated with a layer of high density magnetic material 31 and then bonded to a sub strate such as the paper 32 or the substrate could be a film material if desired. When such a laminate is impacted as by a type slug 15, the paper 32 is embossed with the outline of the character carried by the type slug and the magnetic material of the film 31 is forced into the material of the opaque, porous and coalescible film 30. As shown in FIGURE 6 this brings the high density magnetic particles close to the surface of the film nearest the platen 11 (.2 mil in a 1.0 mil film), producing both a visible outline of the character on the type slug and exhibiting a much more powerful magnetic signal than in the non-impacted areas.

Such an impacted area may be readily detected by means of a magnetic read head 20 brought in contact with the film on the platent side thereof in the impacted area as shown in FIGURE 7. If the matrix is magnetized the signal is significantly greater in the impact, i.e. bit or character area than in the non-impact area, whether the magnetization occurs either before or after impacted.

As shown in FIGURE 8, compression of the opaque, porous and coalescible film by means of scratches would have little effect, since in the signal area the material is already compressed, and in the non-signal area the scratches do not produce any concentration of the magnetic particles on the read head side of the film.

In practice, a .5 mil thick opaque, porous and coalescible film was bonded to the magnetic oxide side of an audio recording tape. When the magnetic oxide was embossed into the opaque, porous and coalescible film by printing an I with an electric typewriter, a visible character was produced on the exposed side of the film by the magnetic particles being compressed into the impacted area of the film. When the tape and the film laminate were passed by a magnetic read head, at approximately 40 inches per second, with the opaque, porous and coalescible film interfacing the head, a usable signal of 3 millivolts was produced by the I typed on the film, with a signal to noise ratio of greater than 10:1, the magnetic tape simulating the paper substrate and magnetic film combination.

Such an opaque, porous and coalescible film when impregnated homogeneously with iron oxide particles can be bonded to checks, mortgage slips, or other documents for correcting MICR checks or producing MICR checks without requiring the use of a separate MICR transfer ribbon as is usually done.

What is claimed is: 1. The method of concurrently producing visible and magnetizable indicia, which comprises the step of:

providing a film of porous and pressure coalescible plastic but substantially uncoalesced polymer material having a substantially homogeneous dispersion of particles of a magnetizable material therein,

applying the film to an embossable non-magnetizable substrate to provide a composite article,

impacting the substrate with a character-bearing type member while the film is backed up by a hard platen to emboss the substrate and thereby compress the film in the impact area to approximately one-fifth its original thickness and concentrate the magnetizable particles just below the exposed surface of the film in a pattern conforming to the visible configuration of such character While precluding embossment of said exposed surface.

2. The method according to claim 1 characterized in that the film comprises a vinylidene type organic polymer.

3. The method according to claim 1 characterized in that the film is of a type which while uncoalesced is substantially opaque and when compressed is relatively clear, thereby to provide a visible character, which as viewed from the film side is a mirror image of the human readable character, to enable authentication of the visible human readable character to discourage and/or detect alteration.

References Cited UNITED STATES PATENTS 2,957,791 10/1960 Bechtold 161-159 3,057,999 10/1962 Newman et a1 1l736.7 3,111,421 11/1963 Newman et a1 ll736.7

ROBERT F. BURNETT, Primary Examiner W. J. VAN BALEN, Assistant Examiner US. 01. X.R.

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