CA1047163A

CA1047163A - Magnetic type information card and method and apparatus for encoding and reading

Info

Publication number: CA1047163A
Application number: CA220,925A
Authority: CA
Inventors: John C. Darjany
Original assignee: R D Products
Current assignee: R D Products
Priority date: 1974-08-21
Filing date: 1975-02-27
Publication date: 1979-01-23
Also published as: US4058839A

Abstract

MAGNETIC TYPE INFORMATION CARD AND METHOD AND
APPARATUS FOR ENCODING AND READING
Abstract Disclosed herein is a flexible resilient magnetic particle type information card capable of correctly reading information thereon after such card has been bent double on itself and creased, said card comprising a flexible base, a layer of uniformly distributed magnetic particles thereon, and a flexible overlayer of nonmagnetic material, said overlayer having a thickness of at least 2 mils, said layer of magnetic particles being magnetically encoded, the magnetic flux transitions of such encoding being at least 0.02 inch apart and said magnetic particle layer being enclosed between the base layer and overlayer and spaced from the edges of the card. Also disclosed is a method of storing information in binary data form comprising magnetically recording information on a magnetic strip that has an overlayer of at least 2 mils by inducing transitions in the magnetization of the strip at a minimum spacing of 0.02-0.1 inch.
A magnetic information card and card reader system are also disclosed comprising the magnetic information card described above in combination with a card reader having a slot accom-modating the card in a tight but not binding fit and a structural portion of the reader having a hole forming a relief opposite the reading head of the reader.

Description

7~63 ~ _ CKGROUND OF THE INVENTION

1. Field o~ the Invention The invention relates to magnetic-type information cards and to a method and apparatus for encoding and reading magnetic-type information cards. More particularly the in-vention relates to mag-stripe information cards which are capable of withs-tanding the abusive and rough treatment of everyday use, such as of students who use -them in magnetic-flux-type readers to determine whether they are entitled to a meal under various meal plans which are encoded on the card together with the identification of the student.

The rough -treatment ~or example which students give to identification and meal plan mag-stripe cards is really unbelievable until one has seen such cards after being used by a large number of students over long periods of use, such as several weeks or months and for two or three times per day.
In many cases the cards are bent back and, iE a rigid type card, are broken; and if flexible, -they are of-ten bent cLouble and creased on the magnetic stripe. The flexible cards are often crumpled and creased. Moreover the users often do not carry the cards in their wallets but instead carry them in their pockets where they may come in contact with keys, coins and the like material which can physically affect the mag-netic stripe if it is not protected by an ade4uate overlay.

-2- ~

7~L63 - While the above such treatment may be particularly prevalent among students, similar rough treatment also occurs with hospital cards, industry and commerce card use and other uses where the cards are used several times per day for months at a time.
These disadvantages of the prior art are overcome by the provision of a flexible resilient lnformation card which can wlthstand treatment such as above described and which can be read after such treatment, including creasing on the magnetic stripe, by magnetic-type readers with a first rejection rate because of an error in reading of less than one per cent of the cards.
Also provided is an information card having a protective layer of 2 mils (.002") or greater thickness over the magnetic layer and which provides the maximum amount of information in a small space and with the least number of tracks without reading error.
Improved methods and means for recording on mag-stripe cards which have a coating of thickness of 2 mils (.002") or greater over the magnetic stripe and for thereafter reading said information are disclosed and claimed herein.
Disclosed, but not claimed herein, are improved means and methods for reading flexible resilient mag-stripe cards having a flexible resilient over layer.
According to one aspect of this invention, a flexible resilient magnetic particle type information card capable of correctly reading information thereon after such card has been bent back double on itself and creased at the region of the card that includes the magnetic particles, is provided. The card comprises a flexible base, a layer of uniformly distributed magnetic particles thereon, and a flexible overlayer of nonmagnetic ~ ~ _ 3 _ \ .

~ ~47~L63 'terial, the overlayer having a thickness of at least 2 mils, the layer of magnetic particles being magnetically digitally encoded, consecutive equal portions of the layer having one polarity of magnetic flux or the opposite polarity, with abrupt magnetic flux transitions between oppositely polarized portions, the magnetic flux transitions of such encodiny being at least 0.02 inch apart and the magnetic particle layer being enclosed between the base layer and overlayer and spaced from the edges of the card.
According to another aspect of this invention, an information card is provided comprising a base, a layer of magnetic particles thereon and an overlayer of nonmagnetic material, the overlayer having a thickness of 2-30 mils and the magnetic particle layer being magnetically digitally encoded, consecutive equal portions of the layer having one polarity of magnetic flux or the opposite polarity, with abrupt magnetic flux transitions between oppositely polarized portion, the minimum spacing between the magnetic flux transitions lying in the range 0.02-0.1 inch.
According to a further aspect of this invention, a method of storing information in binary data form on a strip of flexible magnetizable medium comprises the steps of sealing the strip between at least two layers of flexible resilient material, the layers being longer and wider than the strip, whereby the strip is completely enclosed within the layers, the layer adjacent the magnetizable surface of the strip having a thickness of at least 2 mils, and magnetically recording the information on the strip by inducing transitions in the magnetization of the strip at a minimum spacing of at least 0.02 inch by moving the card laterally such that the magnetizable surface of the strip passes through a region of varying polarity - 3a -~.- ' i Jnetic flux. ~47~63 According to a still further aspect of this invention, a flexible resilient magnetic particle type information card capable of correctly reading information thereon after such card has been bent back double on itself ancl creased at the region of the card that includes the magnetic particles, is provided. The card comprises a flexible base, a layer of uniformly distributed magnetic particles.thereon, and a flexible overlayer of nonmagnetic material, the overlayer having a thickness of at least 2 mils, the layer of magnetic partlcles being magnetically encoded, the magnetic flux transition of such encoding being at least 0.02 inch apart and the magnetic particle layer being enclosed between the base layer and overlayer.
According to another aspect of the invention there is provided the method of storing inEormation in binary data form on a strip of a flexible magnetizable medium sealed between at least two layers of flexible resilient material, the layer adjacent the magnetizable surface of the strip having a thickness of at least 2 mils, the method comprising magnetically recording the information on the strip by inducing magnetic transitions in the magnetization of the strip at a minimum spacing of at least 0.02 inch by moving the card laterally such that the magnetizabl.e surface of the strip passes through a zone of a varying polarity magnetic flux.

- 3b -~1 ~

~4731 1~3 2. Prior Art Flexible mag-stripe information cards are known to the art, for example see Engelhardt et al Pa~ent 3,30~,010, but so far as I know such cards are not in commercial use.
Such cards have a layer over the magnetic oxide layer of ap-proximately 0.5 mils (.0005"). A flexible card with such a thin overlay will not give ade~uate protection against rubbing by keys and the like. Such cards, with the normal prior art magnetic transition spacing, when bend double and creased on the magnetic stripe and then flattened, will give erroneous readings.

So Ear as I know the mag-stripe cards in present commercial use are so rigid that they cannot be bent double and creased without breaking. Also they all have either no overlay or an extremely thin overlay of about 0.5 mils ~.0005") or less. The standard mag-stripe card used by the American Bankers Association is relatively rigid and brittle in bend-ing. It has the magnetic stripe on or very near the surface and is encoded at approximately 225 flux transibions per inch USiIlg one track.

The present trend for information cards appears to be in the direction of mag-stripe cards which are relatively rigid and which have as thin a layer as possible over the mag-netic particle layer, since the thinner the overlay the better the resolution and the greater the information density.

--- ` iO47~.63 The recently issued Kramer Patent 3,811,977 shows an information card analogous to a punch card having magne-tized spots that have a thick overlay of a thickness like that of applicant's invention but such a caLrd is made of rigid vinyl and is not sufficiently flexible to be bent and creased without breaking. Further, the spacing of the mag-netized spots, due to the Kramer system of simultaneous stationary encoding is not desirable or economical when a considerable amount of information is needed on a card.

SUMMARY OF T~E INVENTION

I have discovered that in order to provide a suit-able information card which will satisfy the above objects and advantages of my card invention it is necessary that the magnetic particle layer on the card has an overlayer of a nonmagnetic material of at least 2 mils (.002") thickness and that the magnetic layer be magnetically encoded, the magnetic flux transitions of such enconding being at least 0.02 inches apart such as, for example, 0.02 to 0.10 inches apart.

Any thickness of overlayer of between 2 and 30 mils is sui~able for adequate reading with a spacing of flux tran-sitions of .02 - 0.1 inch, the larger spacings preferably be-ing used with the greater thicknesses of overlayer. However, a thickness of overlayer of 30 mils and ~ore may be used with i3 flux transition spacing of over 0.1 inch but such thicknesses are generally unnecessary and such larger spacings of flux transitions give less information per ca~d than is usually desirable.

I have also found that for flex-ble mag-stripe cards which are subject to bending that the magnetic particle layer or stripe should be enclosed between the base layer or layers and the overlying layer and preferably spaced away from the edges of the card in order to avoid separation of the lamina-10 tions and error in reading which I have found sometimes occurduring use when students and others bend and otherwise roughly treat the cards.
For information cards for use in wallets and in the pocket, such as 2-1/8 x 3-3/8 inch cards and generally for any normal size information card, and sometimes for even larger cards, the lnformation should preferably be recorded in at least -two tracks.

~ lso, I have found that the double track code with data and complimentary bits representing "1" and ~?0", such 20 bits being at the interface of changes in polari~y in either direction gives particularly satisfactory results with my thick ov~rlay. Such a double track code is shown in Phelps Patent 2,774,646 for magnetic tape with flux transition of 1000 per inch and in Mitchell Patent 2,952,008 for a mag-stripe information card with no overlying layer and with f1IL~ tran-sitions o~ 100 per inch.

~L0~7~63 As used in this specification, the term magnetic transitions per inch refers to the number of times in a one inch space along a magnetic track a substantial change in magnetization occurs. Such a substantial change in magneti-zation, i.e. a magnetic transitiorl, may involve a transition from one magnetic polarity to the opposite polarity, as in a non-return to zero system, or it may involve a transition from ~ero magnetization to a magnetization o~ either polarity, or a transition from a magnetization of either polarity back to zero. The quantitative relationship between flux density (flux transitions per inch) and bit density (bits per inch) depends upon the encoding scheme used, the Phelps scheme hav-ing only one transition space per bit, and the American Bank-ing Association card requiring three transition spaces per bit.

I have found that I can provide satisfactor~ magne-tization of the magnetic stripe, even though covered with an overlay having a thickness of between 2 and 30 mils, by em-ploying an ordinary commercial encoding head designed for intimate contact recording, but using a forcing current about one order of magnitude greater than the design value. I have found that such heads have sufficient excess current carrying capacity that they will not burn out under such conditions.

The information card in accordance with one embodi-ment of my invention comprises a flexible and preferably re-silient base sheet which may be of any material which is ~ 6 3 flexible and preferably resilient in sheet form, a strip of homogeneously or uniformly distributed magnetic particles thereon, and a flexible overlayer thereon of nonmagnetic flexible and preferably resilient material having a thickness of at least 2 mils (.002"), preferably 3-10 mils (.Q03"-.010").

Besides being especially durable under rigorous use, my card is also e~tremely difficult to read and/or reproduce without my special reading and/or encoding apparatus, and is therefore very difficult to counterfeit or alter.

The preferred card of this invention is suEficiently flexible so that it can be bent back on itself and creased without breaking and ls so resilient that it will spring back at least part way to its original position. For this purpose at least the base or overlayer shee~, and preferably both, should be flexible and resilient.

The overlying sheet may be one or more sheets of any nonmagnetlc material, preferably an organic material such as polyethylene terephthalate, polyethylene, polypropylene, polyamides, polytetraEluoroethylene, polyvinyl chloride, poly-20 vinyl acetate, cellulose acetate, cellulose, paper and eventhin sheets of nonmagnetic metal foil such as aluminum foil.
Flexible water insoluble organic plastic sheets give better protection than water permeable sheets such as paper. In some cases the organic plastic compound is too brittle in the 2 mil (.002n) thic~ness or greater and must be plasticised or other-wise modified to obtain the desired flexibility and resiliency, ~-- - ~47163 but ~his is all within the state o~ the art.

I have also found it to be of advantage in obtain-ing good;resol~ltion on reading, particularly after bending and creasing of the card, to have the card made of a material which is so resilient and fle~ible that it will bend into an indent or hole on pressure of, for example, 8 pounds per square inch, and spring back a~ter release o~ the pressure.
Many materials known in the art have this property in sheet form o~ at least 2 mils thickness, one such material which has been found particularly satisfactory is a laminate oE
polyethylene terephthalate and polyethylene.

The base sheet may also be of this laminated material and the overlay sheet and base sheet may be heat sealed to-gether by heat and pressure with the t~o polyethylene coat-ings in heat sealing contact; the magnetic strip being sand-wiched therebetween and enclosed thereby so it is spaced from the edges of the card. A photographic film having a picture thereon may also be adhered to the base sheet between the base sheet and the magnetic particle layer, and this also is spaced ~rom the edges of the card.

The inEormation is encoded by a magnetic flux method through the overlayer on and into the layer of magnetic par-ticles so that the El~ transitions on the magnetic tracks are never closer to each other than 0.02 inch. PreEerably, for a thickness of 2-10 mils (.002"-.010") of organ:ic plastic overlay, the minimum spacing bet~een magne~ic transitions ~L~47:~L63 should be in the range 0.02 to 0.10 inch. Pre~erably two tracks are used in our system.

The information is preferably encoded on at least two tracks in order to get a suitable amo1mt of information with the required magnetic transition spacing or ordinary size information cards. For multiple tracks a return to zero coding is suitable but preferably the nonreturn to zero reversal of polarity type coding of Phelps Patent 2,77~,6~6 is usecL.

The magnetic particles may be any of those k~own to the art including ferromagnetic particles such as ~erric oxide particles These may be coated directly in a layer or stripe on the top of the base sheet and laminated to the nonmagnetic overlying sheet, but preferably the particles are coated on a flexible strip of polyethylene terephthalate and this strip with the particles either toward or away from the overlayer, laminate to the base sheet ancl overlayer as in a sandwich.
The thickness of the layer of magnetic particles is not im-portant and suitably may be 0.2 - 1.0 mil or greater.

Preferably the multi tracks are two tracks or mul-tiples o~ two. Those tracks are preferably encoded by a mag-netic flux method of recording as will hereafter be described, preferably using a code system where one track is designated ~Izero~ and the other "one". In the preferred system only one track changes polarity at a time. When the zero track changes polarity a zero ls signified. ~hen the "one" track changes polarity a one is signified.

~ 7~63 In one card having a polyethylene terephthalate upper layer of, for example 5 mils (.00~"), laminated over a layer of ferric oxide magnetic particles of thickness of 0.2 mils two two tracks on the magnetic particle layer have mini-mum spacing between magnetic flux transi-tions oE 0.031 inch.
The bits are at the interface between changed polarities, such alternate changes o~ positive and ~gative polarities b~ing obtained by the magnetic recording system used to en-code the cards.

I prefer to use a reader with a single reading head which is curved and has two magnetic gaps to read the two magnetic strips. ~ significant factor of my reader is that the card has a very close fit in the slot into which it is inserted for reading and the reading head projects somewhat into the slot so as to force the card to be de~ormed into a relief hole opposite the reading head, thereby maintaining a co-nstant pressure between reading head and card and -tending to straighten out any bends or creases in the card.

.
The limits of thickness of overlay and magnetic transitions per inch to give suitable readability on abusive use have been determlned by experimental evidence and theo-retical considerations. I have also considered excessive speed of withdrawing the inEormation card from the reading -apparatus, as well as readability after bending back and creasing.

'7163 The following Table I shows required minimum trànsition spacings for various overlayer thicknesses in order to produce excellent results, i.e. rejection rate because of errors on first reading of less than one per cent with creased cards:

TABLE I

Flux Transition Overlayer Thickness Spacin~ (inches) (mils~
.019 2 .02 3 .022 5 .025 6 .028 7 .033 8 . 0~0 10 .05 15 0.10 30 ~3 The type of material has been considered. The mini-mum thickness of overlay of 2 mils holds :Eor all types of non-magnetic flexib~e material, including organic plastics and cellulose. Even nonmagnetic metal foil should not be thinner than 2 mils for optimum results. However for a ~hickness of overlay of over 2 mils, for any purpose, the problem of reso-lution exists and is solved by the means disclosed in this applied specification.

BRIEF DESCRIPTION OF THE DR~WINGS

FIG. 1 is a plan view of a magnetic card consti-tuting one embodiment of this invention and showing the mag-netic stripe before recording.

FIG. 2 is an expanded sectional view of FIG. 1.

FIG. 3 is a plan view of the recorded magnetic card of FIG. 1 showing in schematic form a two-track recorded mag-netic stripe~

FIG. 4 is an expanded sectional schematic view of the recorded card of FIG. 3 FIG. 5 is a sectional view of the magnetic card of FIG. 1 and FIG. 2 showing the sheets laminated together.

FIG. 6 is an expanded sectional view of another embodiment of the inven-tion showing another type of magnetic stripe information card.

4~.~
FIG. 7 is a sectional view of the embodiment of FIG. 6 showing the top and bottom sheets laminated together.

FIG. 8 is an expanded sectional view of another embodiment of the invention showing the magnetic o~ide layer in reverse of that shown in FIG. 6.

FIG. 9 is a sectional view showing the card of FIG. 8 with the sheets laminated together.

FIG. 10 is a fragmentary sectional view of the in-formation card of ~Iy invention bent double on i~self and ; 10 creased.

FIG. 11 is a fragmentary plan view of the lower portion of FIG. 1 with the two magnetic tracks schematically indicated.

FIG. 12 is a representation of the binary bit in-formation encoded on the card for a typical use system.

FIG. 13 is a schematic and wiring diagram of the apparatus for magnetically encoding the magnetic information card.

FIG. 14 illustrates wave forms generated on par-ticular lines of FIG. 13.

FIG. 15 is a block diagram of the three main com-ponents of the meal plan system which ~orms and is part of the enviro~ment for the present invention.

-14~

~ 47~t~3 FIG. 16 is a schematic and wiring ~iagram of the reading apparatus of FIG. 15 and the initial input portion of the central processor o~ FIG. 15.

FIG. 17 illustrates wave form generated on particu-lar lines of FIG. 16.

FIG. 18 is an elevation view of the molded portion of the reading apparatus which forms the slot and supports the reading head.

FIG. 19 is a sectional view taken along lines 19-19 of FIG. 18.

FIG. 20 is a magnified fragmentary sectional view showing the forced local deformation o~ the magnetic card in the direction of card travel.

FIG. 21 is a magnified fragmentary sectional view showing the forced local deform~tion of the magnetic card in a direction normal to that of ~'IG. 20.

DET~ILED DESCRIPTION OF T~E INVENTION

-1. The Informa-tion Card .
Re~erring to FIG. 1, FIG. 2 and FIG. 5 there. is shown a simple type of magnetic type information card which di.~fers from the information card shown in Engelhardt et al Patent 3,308,010 in that the overlay sheet 8 has a thickness ~ ` ~4;~q;3 of at least approximately 2 mils (0.002"), as for example 5 mils instead of the l/2 mil overlay of the patent, and the powdered magnetic substance, such as ferric oxide (Fe203) is contained in a stripe 2, which is completely-enclosed by the base sheet 1 and , . ... ..
the overlay sheet 8. The substrate 1 also has a thickness o at least 2 mils when made of organic material and like the substrate of the patent may be made of polyethylene terephthalate material of a thickness of S mils. It also may be made of or include a positive film having a photograph thereon, said film for exam-ple being cellulose triacetate of a thickness of S mils. The overlay may be made of polyethylene terephthalate such as Mylar (trademark) having the required thickness to give a tough pro-tective covering of ~or example 3-20 mils. With this thickness the crystaline alignment of Patent 3,308,010 is unnecessary.
The magnetic material and the sandwich of magnetic material be-tween the plastic sheets may be made as described in Patent

3,308,010. However, instead of coating the magnetic layer di-rectly on the substrate there may be used a strip o~ tape hav-ing the oxide coated on it. This is laminated between L~o plastic sheets oE suitable thickness o~ at least 2 mils.

So long as at least one sheet o~ the information card i3 made o~ non magnetic material such as organic plas-tic of a thickness of 3-lO mils a recording such as a double track encoding can be made through the sheet by a method of recording which will be described herein; this recording giv-in ~ double track with between 10 and 50 bits per inch, 7~3 for exampl~ 32 bits per inch. Such multi~track encoding with - such bit spacing allows suitable resolution during reading through the thick overlay on the informat:ion cards, even when creased or crumpled, as described herein. The encoded infor-mation card with the double track is sho~m with the parallel tracks and imaginary bits as dots in ~IGS J and 4.

FIGS. 6-9 show more sophisticated embodiments of in-formation cards both of which have given highly satisfactory results from the point of view of wear resistance and read-ability.

Referring to FIG. 6, the information card of a pre-ferred embodiment of the invention includes a base sheet 1 which may illustratively have a thickness of 3 mils having a polyethylene heat sealable layer 3 laminated to it, of pref-erably a thickness of 2 mils. The base sheet 1 may be made of polyethylene terephthalate material. The base sheet 1 may have a generally rectangular configuration, illustra~
tively 2 inches by 3-3/8 inches, and may be transparent or not. Secured to the polyethylene layer 3 of the base sheet 1 is a positive film 5 having a photograph and other infor-mation thereon, the photograph and information facing the polyethylene layer 3 so they are visible through the base sheet 1. The positive film may be of a cellulose acetate such as cellulose triacetate. Preferably a curable acrylic glue or other adhesive 4 is coated on both sides of the posi-tive film 5. Secured to the positive film 5 on the nonphoto-graphic side is magnetic oxide stripe 2 which does not extend ~ 7~3 to the edges of tl~e underlying and overlying sheets as shown in FIG. l. This magnetic oxide stripe 2 may comprise a layer of ferric oxide particles mixed with an adhesive and wetting agent as is well known in -the art and described in Patent 3,308,010.
The layer 2 may illustratively have a thickness of 0.8 mil and is, for the preEerred embodiment, coated on a polyethylene tere-phthalate (Mylar) (trademark) sheet 6. The oxide layer 2 is the embodiment shown in FIG 6 and FIG. 7 is against the posi~ive film layer 5 adhered to it by the adhesive layer 4. Laminated to and extending beyond the Mylar ( rademark) layer 6 and oxide layer 2 of the mag-stripe is a polyethylene layer 7 coated on the under side o~ polyethylene terephthalate layer 8. Illustra-tively the Mylar (trademark) sheet 6 has a thickness of 2 mils, the polyethylene layer 7 a thickness of 2 mils and the top Mylar (trademark) sheet 8 a thickness of 3 mils so that the total thick-ness of plastic over the magnetic oxide layer is appro~imately 7 mils.

FIG. 7 shows the layers of FIG. 6 laminated and se-cured together. It will be noted that the polyethylene coated Mylar (trademark) layers 8, 7 and 1, 3 are brought tog~ther and seal in the magnetic stripe 2 and the positive film 5. The mag-netic stripe 2 on base 6 ~ith adhesive 4 on both sides of -the film 5 are indicated by the numeral 9 in FIGS. 5, 6, 7 and 8.
The sealing together may readily be accomplished by heat and pressure to produce a heat seal because of the character of the polyethylene layers 3 and 7. It is preferable, ~rom the stand-point of desirability, that the mag-stripe be sealed on all sides as shown in FIG. 1 and FIG. 3.

FIGS. 8 and 9 show the same arrangement as in FIGS. 7 and 8 except that the mag-stripe is reversed so tha~ oxide layer 2 is against the polyethylene layer 7, and the Mylar (trademark) base 6 of the mag-stripe i~, against the adhesive 4 and positive film layer 5. This makes a plastic overlay or covering for the magnetizable oxide o~ 5 mils instead of the 7 mils of FIGS 6 and 7.

FIG. 10 shows the card of FIG. 2 doubled back on it-self and creased, the crease being on the magnetic stripe length or transverse to it. Such a card, if constructed and encoded pursuant to the principle of my invention, may be read satisfac-torily in the reading apparatus of my invention. The relatively thick overlay on the magnetic stripe does not appear to reduce the readability of a bent or creased card as much as one would expect. While I do not wish to be bound by this theory, it is hypothesized that the creasing is primarily a surface effect, and that the distortion effect of creasing on the actual magnet-ic stripe is greater when the magnetic stripe is at or near the surface oE the card than when the stripe has a relatively thick overlay as in our invention. In other words, the overlay may diffuse the distortion effect of a crease on the actual magnetic medium. This effect would tend to reduce the change in magnetic intensity which would normally be severe in the case of bent or creased cards, and I believe, to a large extent, accounts for the unusually high readability I obtain with my bent or creased cards.

~14'~i~63 - 2. _ e Encodin~ Apparatus And Method Referring to FIG. 11, the lower portion of the infor~
mation card 10 of FIG. 1 is shown in enlarged form. The homo-geneous magnetic medium forming magnetic stripe 2 is disposed inwardly on the side and bottom edges o~ the cards, that is, it does not extend to any edge of the card. This aspect of my in-vention contributes substantially to the durability of the card under the rigorous conditions of use. In the preferred embodi-ment, the magnetic stripe 2 is 0.5 inch wide and 3.19 inches long, and the card extends b0yond the ends of the stripe 0.0925 inch and beyond the bottom of the stripe 0.3125 inch. These dimensions assume a standard 2.125 inch by 3.375 inch card.
Similar dimensions are arrived at when using other standard sizes such as 2.3125 inches by 3.250 inches.

Reference numerals 11 and 12 schematically represent the two magnetic data tracks where the information is magneti-cally recorded, the upper track 11 being reserved for binary zero's and the lower track 12 being reserved for binary one's.
As indicated, in the preferred embodiment, the two tracks are each 0.08 inch wide and 0.08 inch apart. Although the entire length of the magnetic stripe is potentially capable of carry-ing magnetic data, in the particular card of my specific em-bodiment only the right-most (in FIG.ll) two inches can be used since the left side of the card is used to hold the card while it is being ~ead. In one information system where I
employ the card, only that one inch length o~ each track in-dicated in FIG. 11 as a "data recording area" is employed, 7~L63 since this length is sufficient to record the desired infor-mation in this particular system. In another system I employ the full usable two inches.

FIG. 12 shows the use which is rnade in my system of the space for the 32 bits afforded by the one inch length of data recording area. Bit No. 1, the left most bit in FIG.
12, is a flag bit, always a one, the purpose of which will be described hereinafter. A hexadecimal even parity five bit system is employed, the parity bits being zero or one as is necessary to make the total number of ones in each five bit byte an even number. ~ach parity bit and the following four bits constitute one byte, either a decimal digit from zero to nine or a letter from A to F. Bits 2 through 21 are used to identify a four digit account number individual to the user to whom the card is issued, for example, account number 309~.
In the case of student boarding plans bits 22 through 31 are used to define the particular meal plan to which the student has subscribed, for example, meal plan 3F. In my particular system, the space ~or a thirty-sacond bit is not needed and is not used. Accordingly, a total of 31 bits are actually recorded and later read from each card.

FIG. 13 is a schematic representation of tha record-ing apparatus employed in my system, the arrowa denoting the direction of flow of information. FIG. 13 is best understood when taken together with FI&. 1~ which indicates ~he wave forms transmitted on lines A, B, C, D, C1 and D' of FIG. 13 ~21-~ ~ ~ 7~ ~ ~

in the exemplified situation where the bit series being re-corded is 11000110010.

A standard manual hexadecimal keypad 13 is used to introduce the account number and plan information~ e.g.
3c943F, into the recording apparatus where t iS stored in a standard storage register 14 until the card recording is made and verified. Simultaneously, the information punched into the keypad is displayed, as indicated at 15, so that the operator may verify his punching operation.

The card is inserted in a track in the recording apparatus and is caused to move from left to right, along the path indicated by reference numeral 16, by a constant speed drive indicated schematically by drive rollers 17, 17'. As the card traverses the track, its two magnetic tracks 11 and 12 first pass adjacent a two gap recording head 18 and then a two gap reading head 19. A card position sensing system consists of a directional lamp 20 which directs a narrow beam of light across the path of the card at a light sensitive senson 21 such as a photoelectric cell. The spatial arrange-ment is such that when the card interrupts the light beam, the magnetic recordings area of the two tracks is just begin-ning to pass under the respective gaps of recording head 18.
The interruption of the light beam is signalled to the con-trol circuit 22 and storage register 14, as on line ~, thus initiating the serial release of the stored information from storage register 1~ to control circuit 2~, as on line ~.

~ ~ 7 ~ 6 ~
A clock circuit 23 generates a constant frequency square wave clock pulse as indicated at B of FIG. 1~, which pulse is fed to the storage register 14 and the control cir~
cuit 22. The frequency of the clock pulslP is coordinated in the initial design with the constant speed of travel of the card such that, in our specific example, there are exactly 32 evenly spaced bit spaces on the one inch lengths of data re-cording area which is used. The bit spaces are thus 0~03125 inch long, or to state it differently, the bits are 0.03125 inch apart. As will later be clear, in the particular two track encoding system I use (Phelps U.S. Patent 2,774,46~), there is a one to one relationship between bit spacing and the smallest possible spacing between magnetic transitions on a mag-netic track, such as occurs when a binary number repeats itself, such as in zero-zero series or a one-one series. Thus the smal-lest possible spacing between magnetic transitions on a track is 0.03125 inch, or to state it another way, the magnetic transi-tions on a track are at least 0.03125 inch apart in the particu-lar card I use. As explained elsewhere, the spacing oE the mag-netic transitions on a track is an important aspect of my in-vention. In accordance with the invention, the magnetic tran-sitions should be at least 0.02 inch apart, corresponding, in the Phelps two track encoding system, to an information density of 50 ~its per inch. As indicated this magnetic transition spacing is physically determined in the recording apparatus by the frequency of the clock pulse and the speed of the card drive system.

7163`
Referring particularly to FIG. 14 wave form A repre-sents the manner in which the stored binary data is sent from the storage register 14 to the con-trol circuit 22. It will be noted that the ones and the zeros are distinguished at this point solely by a difference in signal amplitude in the normal manner. I'he control circuit 22 generates, from signal A and the clock pulse, write current signals C and D which la-tter signals are fed respectively to the one and zero coils of recording head 18. In accordance with the aforementioned Phelps encoding sys-tem, the write current signal C reverses direction each time abinary 1 appears and at no other time. Similarly, the write current signal D reverses direction each time a binary zero ap-pears and at no other time. Thus, a binary one will result in a reversal of polarity of the magnetization of the "one" trac~ 12 and a binary zero will result in a reversal of polarity of the magnetization of the "zero" track 11. It should be noted that the direction of the reversal is of no significance, and that there is a reversal, either on the one track of zero track for each bit spacing, i.e. for each full wave length of the clock pulse.

C' and D' in FIG. 1~ represent the wave forms of the read current signals induced in the respective coils of reading head 19 by the magnetization resulting from writing signals C and D, respectively. Since C' and D' and therefore the time derivatives of C and D, respectively, a pulse occurs on line C' of FIG. 13 wherever a one appears, and a pulse occurs on line D' wherever a zero appears. Here again the -2~-:~0~71~
polarity of the pulse is of no signi~icance, and a pulse occurs on ei-ther line C' or D' for each bit. The read sig-nals C' and D' are fed to a comparator 24 where the binary series represented thereby is compared with the binary series received from the storage reservoir to verify that the re-cording operation has bsen free of error.

The Phelps U.S. Patent 2,774,646 may be referred to for details of suitable conventional circuity for gener-ating ~he write current C and D of the two track system.

An important aspect of my invention has to do with the severe problem of producing satisfactory magnetization of a magnetic stripe which is covered with an overlay having a thickness of 2 mils or more. Recording heads on the market are designed for recording on immediately adjacent or nearly adjacent magnetic stripes since the magnetic information cards in use have little or no coating. The problem was solved by utilizing a forcing writing current about an order of mag~
nitude greater than the normal design writing current of the recording head. For example, I use a Nortronics Encoding 2~ Head model DQ21G048S19 to encode magnetic cards having a 5 mil overlay on the magnetic stripe. The recommended write current for this head is 12 milliamps. (Nortronics Design Digest~ Mini-Digital Magnetic Recording, 3rd edition, page 24.) Recording through the 5 mil overlay could not be ac-complished at or near the recommended writing current. Sur-prisingly, I found that when I used a forcing current of 100 milliamps, not only was satis~actory recording effected but the recording head did not burn out or su~fer any other ill ef~ect.

3. The Readin~ Apparatus And Method Referring to FIG. 15, in the interests of complete-ness, there is shown in block ~orm the complete meal plan sys-tem which forms and is part o~ the environment ~or the present invention. In the case of a meal plan system application a card reader 25 is located at the dining room entrance to veri-fy that the student is entitled to the meal currentLy beingserved. The magnetic card 10 is inserted into the slot, in-dicated at 26, and signals that it has been inserted all the way by depressing the button 27 of switch 28. The card could be read upon insertion or upon withdrawal, but I pre~er to read it upon withdrawal since it is ~ound that the speed o~
manual withdrawal tends to be more constant than the speed o~
manual insertion.

The signal that the card has been inserted is sent to the memory and central processor 29 by way o~ transmission channel 30 and such signal clears a shift regis-ter in proces-sor 29 so that it can receive and store the in~ormation as to student identi~ication and meal plan which is read as the card is being withdrawn and transmitted serially to the processor via transmission channel 30.

L~
A keyboard and control terminal 31 is provided for the cafeteria business o~fice to initially put into the memory of the control processor, by way of transmission channel 32, information as to the meal plans to which the individual stu-dents have subscribed and to revise such information as may be necessary thereafter for one reason or another. The opera-tor of the keyboard and control terminal, besides adding, de-leting or revising information in the memory, can also query the memory as to the status of an individual account, total current meals eaten by all students, etc., and such informa-tion is transmitted back to the control terminal 31 from the processor 29 and displayed as indicated at 33.

Receipt by the processor 29 from card reader 25 of the account number and meal plan information read from a card automatically initiates a query of the memory as to whether the memory contains any information under the particular account number, and if so, the status of the account. The processor 29 sends back to the card reader 25 any one of five responses, as indicated by signal lights 36, namely (l) "pass"
- the account is valid and entitled to the current meal; (2) "meal eaten" - the acco~mt is valid but the current meal has already been eaten; (3) "card invalid" - the meal privileges for this account have been withdrawn; (4) "max meals eaten" -the account is valid but the maximum number of meals to which entitled under the particular meal plan have been eaten; and (5) "reinsert card" - this direction appears if parity on the card or in the communication link shows an error or if an account number is read for which there is no record in the memory of the central processor. When th~e c~ntral processor reports "pass" to the reader, it also automatically appropriate-ly revises the memory by adding one to the number of meals eaten.

~ le card reader also receives from the central proc-essor information as to total current meals eaten by all stu-dents, as indicated at 3~ and also information as to the num-ber of meals eaten by the individual student in the current week or other meal plan period, this latter information being flashed momentarily at 3~.

In the usual instaLlation, the memory and central processor 29 is a special purpose digital computer designed and wired using conventional data processing techniques for this particular application, and it and the keyboard and con-trol terminal 31 are located at or near the cafeteria together with the card reader. However, the memory and cen~ral proc-essor 29 and/or the keyboard and control terminal 31 may be remotely located, and the memory and central processor may be a time-shared general purpose computer, e.g. in IBM SYSTEM/7, which is especially programmed for this application. In a situation where the central processor 29 and/or keyboard and control terminal are located remotely from the card reader or from one another, the transmission channels 30 and 32 may consist of an ordinary telephone line having a MODEM termi-nation at each end over which line digital informat:ion is transmitted as a constant amplitude signal of two difEerent ~ 0~3-` ~
frequencies associatedr~sp~c~luDly ~ith zeros and ones. A
single telephone line will suffice in each case since infor-mation is being transmitted in only one diirection at a time.

Referring now to FIG. 16, wherein the electrical system for the reading and initial processing of the informa-tion magnetically encoded on the two traclcs is shown, refer-ence numeral 19' represents a reading head in card reader 25 having two gaps ~0 and 41. The reading head is spatially re-lated to slot 26 such that the "one" magnetic track of card 10 passes over the zero gap ~1, as card 10 is withdrawn from its fully inserted position in the reader. As with the re-coding head 19 of FIG. 13, I prefer to use a single reading head having two magnetic gaps, although two separate reading heads could be used if desired. In the preferred form of my system, I use a ~ortronics Model B2H2K-NO reading head as heads 19 and 19' of FIGS. 13 and 16.

Coils ~2 and ~3 associated with gaps ~0 and ~
respectively, feed the amplifier and integrators ~ and ~5, respectively, the outputs C" and Dl' of which feed respective full wave rectifiers 46 and 47, respectively. The output C"' o full wave rectifier 46 provides one input to the "OR" cir-cuit ~8, the other input to the "OR" circuit being provided by the output D"' of full wave rectlfier ~7. me output C"' of full wave rectifier 46 can be considered as the "data"
line and it provides the data input to a conventional 32 bit shift register ~9 at the input side of the central processor 29. me output of the "OR" circuit ~8 provides, as will hereinafter be apparent from ~IG. 17, a clock pulse for the shift register 49.

In FIG. 17, the wave forms of the various signals C", D", C"', D "', and clock signal E are shown for the same illustrative case as was used in connection with FIG. 14, namely a binary series 11000110010. In recorder of FIG. 13, the speed of the card was constant and therefore the signals C' and D' generated in the respective coils of reading head 19 were of a constant amplitude, as indicated in ~IG. 14. In the case of the reader 19', however, the speed of the card 1 may change as i~ is manually withdrawn :Erom the reader. Am-plifiers and integrator 44 and 45, acting as clipper circuits, are therefore used to process the variable amplitu~e signals (not shown) from coils 42 and 43 into constant amplitude signals ~" and ~" identical to signals C' and D' of FIG. 14O
The ~ull wave rectifiers and shapers 46 and 47 transform the bipolar signals C" and D" into unidirectional square wave signals C"' and D~', respectively, a positive square wave pulse appearing on line C"' at every bit space containing a "one" and an identical positive square wave pulse appearing on line "D" at every bit space containing a zero. Inasmuch as in thè illustrated system of decoding (the aforesaid Phelps system) a "zero" or a "one" appears at every bit space, the output E of the "OR" circuit 48 necessarily exhibits a pulse at every bit space, and it can therefore be used as the clock pulse input to shift register 49. It will be apparent that the present data reading and processing system is self clocking irrespective of variation in the speed of card 10 during withdrawal from the reader.

As card 10 is withdrawn from the reader, the shift register is serially filled up with, for lexample, the 31 bit binary series recorded on the card, "one" being entered at every bit space where a clock pulse and a "one" simultaneously occur on lines E and C"', respectively, and a "zero" being entered at every bit space where a clock pulse occurs on line E and no signal appears on line C"'. The transferral of the complete binary series from the card 10 to the shift register 49 is signaled by the entree of the "one" f].ag bit from bit space No. 1 o~ the card (see FIG. 12) in the 31st bit space of the shiEt register. The complete binary series can then provide the conventional parallel data input to the remainder of the central processor on output lines 50, as indicated.

Also shown in FIG. 16 is the operating button 27 of switch 28 described in connection with FIG. 10. When the card 10 is fully inserted in reader 25, the closing of switch 28 provides a signal which resets register ~9 so that it is ready to receive a new binary series as the card is withdrawn.

Referring to FIGS. 18 through 21, there is shown a molded portion 51 of reader 25 which form~ slot 26 and sup-ports reading head 19 in a position underneath the card. The slot 26 has dimensions only the slightest bit greater in width and thickness than the width and thickness of the card itself.
Thus, very little play of the card is possible laterally or up and down when it is inserted into the slot. In ~iew of ~ this relatively tight, but not binding fit, a larger (in both directions) opening 52, is provided in the front face of the molded portion 51, and the inwardly slanting planes 53 con-necting this longer opening with slot 26 form a kind of fun-nel to facilitate the manual insertion of the card into the slot. The relatively tight, but not binding fit, of the card in the slot, when taken with the previously described flexi-bility and resiliency characteristics of the card itself, has the important beneficial effect of tending to straighten Ollt and remove creases from bent and/or creased cards.

An important ~eature of the invention is that the reading head 19' is positioned so that its operating end ~which contains the magnetic gap) extends an appreciable dis-tance into the slot 26, as best seen in FIGS. 19 and 20. For example, assuming a card thickness (and slot width) of 22 mils, the reading head should extend into the slot about 7 mils.
In order to accomodate the thickness of the card at the read-ing head a rectangular relief hole, indicated as 54, is pro-vided in the molding on the opposite side from the readinghead. As indicated in FIGSo 19 and 20, the hole is the same dimension as the reading head along the direction of travel of the card. In a direction normal to the direction of travel of the card, the dimension of the hole must be somewhat greater than that of the reading head, preferably about 1/16 inch, as best seen in FIGS. 18 and 21.

~47~3 When the card is inserted into the slot, its lead-ing edge strikes the rounded surface of the reading head 19'.
Sufficient force must then be applied to force the portion of the card in contact with the reading head up and around the curved portion so that it conforms to the curved surface, and its upper side extends in th~ same curved fashion into hole 54, as best seen in FIG. 20. In the direction normal to the direction of travel of the card, the fact that the hole has a greater dimension than the reading head provides sufficient leeway to permit the card to extend up into the hole, as best seen in FIG. 21. Thus, there is ef:Eected a localized region of stress and deformation of the card about equal in area to that of the reading head, which region travels along the length of the card as the card is inserted and withdrawn from the reader. When taken in association with the flexibility and resilience characteristics of the card, this localized deformation has two important advantageous effects~ the card maintains a continuous and repeatable pressure over about a one-half square inch surface of the reading head of an ap-propriate value of about eight pounds per square inch, and(2) any bends or creases in the card in the area containing the magnetic medium tend to be removed as the card is inserted.

In summary, a number oE features of my overall sys-tem cooperate in a unique way to provide an information card and associated apparatus which are especially durable and reliable under rigorous conditions of use in the field, the more important of these features being the following:

~L7~63 - (1) the provision of a margin on all sides o~ the sealed magnetizable medium;
(2) the thickness and composition, as described, of the various layers making up the cards;
(3) the provision o~ a protective overlay of at least 2 mils over the magnetic stripe;

(4) use of a self-clocking encoding system, such as the Phelps system, which has a high information content per magnetic - transition;

(5) the maintenance of a minimum spacing between magnetic transition o~ at least 0.02 inch on any track;

(6) the use of a very high forcing current in the recording .head used to encode the magnetic stripe through the over-lay; and

(7) the provision of a relief hole opposite the reading head in association with a unique spatial relationship between card, card slot, and reading head, such that a portion o~ .
the card is locally stressed and deformed into the relief hole as it is inserted into the slot.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A flexible resilient magnetic particle type information card capable of correctly reading information thereon after such card has been bent back double on itself and creased at the region of the card that includes the magnetic particles, said card comprising a flexible base, a layer of uniformly distributed magnetic particles thereon, and a flexible overlayer of nonmagnetic material, said overlayer having a thickness of at least 2 mils, said layer of magnetic particles being magnetically digitally encoded, consecutive equal portions of said layer having one polarity of magnetic flux or the opposite polarity, with abrupt magnetic flux transitions between oppositely polarized portions, the magnetic flux transitions of such encoding being at least 0.02 inch apart and said magnetic particle layer being enclosed between the base layer and overlayer and spaced from the edges of the card.

2. An information card in accordance with Claim 1 in which the information is encoded in at least two tracks along said layer of magnetic particles, and the flux transi-tions are 0.02 to 0.10 inch apart.

3. An information card in accordance with Claim 2 in which one track represents "ones" and the other track "zeros", bits of said information are at the interface of a change in polarity in either direction, and there is a change of polarity on one track or the other at each of the spaces between bits.

4. An information card in accordance with Claim 1 in which the overlayer is an organic plastic having a thickness of 2-10 mils and the minimum magnetic transition spacing being in the range of 0.02 to 0.10 inch.

5. An information card in accordance with Claim 4 in which the organic plastic overlay is polyethylene tere-phthalate having a coating of polyethylene on its underside.

6. An information card in accordance with Claim 1 in which the card base is a sheet of polyethylene terephthal-ate having a layer of polyethylene thereon and including a sheet of cellulose acetate with one side against the said layer of polyethylene, the magnetic particles are coated on a strip of polyethylene terephthalate and are between the base sheet and the overlay sheet, and the overlay sheet is a sheet of polyethylene terephthalate having a layer of polyethylene thereon, the layer of polyethylene on the base sheet and on the overlayer being in contact with each other at the four edges of the card and adhering together so as to completely enclose the strip of magnetic particles.

7. An information card in accordance with Claim 1 in which the card base comprising a polyethylene terephthalate sheet having a layer of polyethylene thereon and a sheet of cellulose acetate on the said layer of polyethylene, the mag-netizable particles are on a sheet of polyethylene terephthal-ate with the polyethylene terephthalate being against the cellulose acetate sheet, and the over layer comprises a layer of polyethylene over the oxide layer and an upper sheet of polyethylene terephthalate on the polyethylene layer.

8. An information card in accordance with Claim in which an acrylic adhesive is on both sides of the cellu-lose acetate sheet so as to secure the magnetizable layer to one side of the cellulose acetate sheet and the base poly-ethylene layer to the other side of the cellulose acetate sheet.

9. An information card in accordance with Claim 7 in which an acrylic adhesive is on both sides of the cellu-lose acetate sheet so as to secure the cellulose acetate sheet to the polyethylene layer on the underside of the over layer of polyethylene terephthalate.

10. An information card in accordance with Claim 1 in which the magnetizable particles are in a stripe and com-pletely enclosed so that the stripe of said particles stops short of all edges of the base and overlay material.

11. An information card in accordance with Claim 1 in which the card base comprises a sheet of polyethylene tere-phthalate having a layer of polyethylene thereon and a sheet of cellulose acetate on said layer of polyethylene, the mag-netic particles are on a strip of polyethylene terephthalate with the magnetic particles against the sheet of cellulose ace-tate and the polyethylene terephthalate on which the magnetic particles are coated is against the polyethylene layer of the overlying polyethylene terephthalate sheet.

12. A flexible information card comprising a flexible base, a layer of magnetic particles thereon and a flexible over-layer of nonmagnetic material, said overlayer having a thickness of 2-30 mils and said magnetic particle layer being magnetically digitally encoded, consecutive equal portions of said layer hav-ing one polarity of magnetic flux or the opposite polarity, with abrupt magnetic flux transitions between oppositely polarized portion, the minimum spacing between said magnetic flux transi-tions lying in the range 0.02-0.1 inch.

13. The method of making a recorded information card having information in binary data form on a strip of flexible magnetizable medium comprising sealing said strip between at least two layers of flexible resilient material, said layers being longer and wider than said strip, whereby the strip is completely enclosed within said layers, the layer adjacent the magnetizable surface of said strip having a thickness of at least 2 mils, and magnetically recording said information on said strip by inducing transitions in the magnetization of said strip at a minimum spacing of at least 0.02 inch by moving said card laterally such that the magnetizable surface of the strip passes through a region of varying polarity magnetic flux.

14.The method in accordance with Claim 13, wherein said recording step includes applying a forcing current to an intimate contact recording head having a value about an order of magnitude greater than its normal intimate contact record-ing current.

15. The method in accordance with Claim 13 wherein both layers of flexible material have a thickness of at least 2 mils.

16. A method in accordance with Claim 13 wherein the layer adjacent the magnetizable surface of said strip has a thickness in the range of 2-10 mils and said transitions have a minimum spacing in the range 0.10 - 0.02 inch.

17. A method in accordance with Claim 13, wherein said transitions are induced along two independent parallel tracks on said strip, binary ones being represented by a change of polarity of magnetization on one of said tracks and binary zeros being represented by a change of polarity of magnetization on the other of said tracks, a change of polarity occurring at regularly spaced intervals along said strip on one or the other, but not both, of said tracks.

18. A method in accordance with Claim 13, wherein the layer adjacent the magnetizable surface of said strip has a thickness in the range of 2-10 mils and said transitions have a minimum spacing in the range 0.10 - 0.02 inch, said recording step including applying a forcing current to an intimate contact recording head having a value an order of magnitude greater than its normal intimate contact recording current, and said transi-tions are induced along two independent parallel tracks on said strip, binary ones being represented by a change of polarity of magnetization on one of said tracks and binary zeros being rep-resented by a change of polarity of magnetization on the other of said tracks, a change of polarity occurring on one or the other, but not both, of said tracks at regularly spaced intervals along said strip.

19. A flexible resilient magnetic particle type in-formation card capable of correctly reading information thereon after such card has been bent back double on itself and creased at the region of the card that includes the magnetic particles, said card comprising a flexible base, a layer of uniformly dis-tributed magnetic particles thereon, and a flexible overlayer of nonmagnetic material, said over layer having a thickness of at least 2 mils, said layer of magnetic particles being magneti-cally encoded, the magnetic flux transitions of such encoding being at least 0.02 inch apart and said magnetic particle layer being enclosed between the base layer and over layer.

20. An information card in accordance with Claim 19 in which the information is encoded in at least two tracks along said layer of magnetic particles, and the flux transitions are 0.02 to 0.10 inch apart.

21. An information card in accordance with Claim 20 in which one track represents "ones" and the other track "zeros", bits of said information are at the interface of a change in polarity in either direction and are evenly spaced, and there is a change of polarity on one track or the other at each of the spaces between bits.

22. An information card in accordance with Claim 19 in which the overlayer is an organic plastic having a thickness of 2-10 mils and the minimum magnetic transition spacing being in the range 0.02 to 0.10 inch.

23. An information card in accordance with Claim 22 in which the organic plastic overlay is polyethylene terephthal-ate having a coating of polyethylene on its underside.

24. An information card in accordance with Claim 19 in which the card base is a sheet of polyethylene terephthalate having a layer of polyethylene thereon and including a sheet of cellulose acetate with one side against the said layer of poly-ethylene, the magnetic particles are coated on a strip of poly-ethylene terephthalate and are between the base sheet and the overlayer, and the overlayer is a sheet of polyethylene tere-phthalate having a layer of polyethylene thereon.

25. An information card in accordance with Claim 19 in which the card base comprising a polyethylene terephthalate sheet havig a layer of polyethylene thereon and a sheet of cel-lulose acetate on the said layer of polyethylene, the magnetiz-able particles are on a sheet of polyethylene terephthalate with the polyethylene terephthalate being against the cellulose ace-tate sheet, and the over layer comprises a layer of polyethylene over the oxide layer and an upper sheet of polyethylene tere-phthalate on the polyethylene layer.

26. An information card in accordance with Claim 25 in which an acrylic adhesive is on both sides of the cellulose acetate sheet so as to secure the magnetizable layer to one side of the cellulose acetate sheet and the base polyethylene layer to the other side of the cellulose acetate sheet.

27. An information card in accordance with Claim 26 in which an acrylic adhesive is on both sides of the cellulose acetate sheet so as to secure the cellulose acetate sheet to the polyethylene layer on the underside of the over layer of poly-ethylene terephthalate.

28. An information card in accordance with Claim 19 in which the magnetizable particles are in a stripe and com-pletely enclosed so that the stripe of said particles stops short of all edges of the base and overlay material.

29. An information card in accordance with Claim 19 in which the card base comprises a sheet of polyethylene tere-phthalate having a layer of polyethylene thereon and a sheet of cellulose acetate on said layer of polyethylene, the magnetic particles are on a strip of polyethylene terephthalate with the magnetic particles against the sheet of cellulose acetate and the polyethylene terephthalate on which the magnetic particles are coated is against the polyethylene layer of the overlying poly-ethylene terephthalate sheet.

30. The method of storing information in binary data form on a strip of a flexible magnetizable medium sealed between at least two layers of flexible resilient material, the layer adjacent the magnetizable surface of said strip having a thick-ness of at least 2 mils, said method comprising magnetically re-cording said information on said strip by inducing magnetic tran-sitions in the magnetization of said strip at a minimum spacing of at least 0.02 inch by moving said card laterally such that the magnetizable surface of the strip passes through a zone of a vary-ing polarity magnetic flux.

31. The method in accordance with Claim 30 wherein said recording step includes applying a forcing current to an intimate contact recording head having a value about an order of magnitude greater than its normal intimate contact recording cur-rent.

32. The method in accordance with Claim 30 wherein both layers of flexible material have a thickness of at least 2 mils.

33. A method in accordance with Claim 30 wherein the layer adjacent the magnetizable surface of said strip has a thickness in the range of 2-10 mils and said transitions have a minimum spacing in the range 0.10 - 0.02 inch.

34. A method in accordance with Claim 30, wherein said transitions are induced along two independent parallel tracks on said strip, binary ones being represented by a change of polar-ity of magnetization on one of said tracks and binary zeros being represented by a change of polarity of magnetization on the other of said tracks, a change of polarity occurring at regularly spaced intervals along said strip on one or the other, but not both, of said tracks.

35. A method in accordance with Claim 30, wherein the layer adjacent the magnetizable surface of said strip has a thickness in the range of 2-10 mils and said transitions have a minimum spacing in the range 0.10 - 0.02 inch, said recording step includes applying a forcing current to an intimate contact recording head having a value in order of magnitude greater than its normal intimate contact recording current, and said transi-tions are induced along two indepepdent parallel tracks on said strip, binary ones being represented by a change of polarity of magnetization on one of said tracks and binary zeros being repre-sented by a change of polarity of magnetization on the other of said tracks, a change of polarity occurring on one or the other, but not both, of said tracks at regularly spaced intervals along said strip.