US3442699A

US3442699A - Electric signal recording blank

Info

Publication number: US3442699A
Application number: US479904A
Authority: US
Inventors: Harold R Dalton
Original assignee: HAROLD R DALTON
Current assignee: HAROLD R DALTON
Priority date: 1965-08-16
Filing date: 1965-08-16
Publication date: 1969-05-06
Anticipated expiration: 1986-05-06

Description

May 6, 1969 FIG. 4

H. R. DALTON ELECTRIC SIGNAL RECORDING BLANK Filed Aug. 16, 1965 MHSKlA/G CON f//VG INVENTOR.

#420.10 A? 0,44 roA/ United States Patent O 3,442,699 ELECTRIC SIGNAL RECORDING BLANK Harold R. Dalton, 931 Rydal Road, Jenkintown, Pa. 19046 Filed Aug. 16, 1965, Ser. No. 479,904 .Int. Cl. B44d 1/18, 1/14; H01!) 1/04 U.S. Cl. 117-201 25 Claims ABSTRACT F THE DISCLOSURE This invention relates to recording blanks, and more particularly to multiple or multilayer blanks for recording electric signals such as facsimile signals and the like. More specifically the invention is that of such an electric signal recording blank having a relatively light-colored outer or masking layer throughout which there is distributed nely divided particles of a ferroelectric or ferromagnetic material or a mixture of any of these high dielectric constant materials. Inclusion of the high dielectric constant material in these recording blanks provides not only improved recordings but also improved operation particularly with the multiple recording electrodes or styli in systems employing a plurality of them.

The facsimile recording art uses in general two types of recording blanks, (a) the photographic type and (b) the direct recording type. The photographic blank has the disadvantage that the recording machine must be operated under dark room conditions, and comparitively relatively expensive photographic developing equipment and operations are required to provide a complete record.

The direct recording blank may be divided into four groups, pressure sensitive, electrolytic, electrostatic, and dry electronic. Except for the photoconductive electrostatic recording blank, the direct recording blanks can be used under normal light conditions and the record is immediately and permanently produced as the electric signals are being received.

One kind of heretofore found useful direct recording blank comprises a backing or web of paper having applied to it a white masking coating which is removable and/ or decomposable in localized areas in response to applied electric signals, so as to expose the under surface which is black and electrically conductive.

Thus, in one known such blank, the paper backing itself is rendered electrically conductive to a predetermined degree by having incorporated in it a conductive material such as powdered carbon or carbon black. In another known blank, the paper backing can be any usual kind of paper having one of its surfaces treated or coated with a conducting material consisting to a great extent of carbon black, to give it the necessary electrical conductivity and blackness for contrast.

In either of these two types of blanks, the black conductive or under surface is masked by the white masking coating. It is the masking coating which responds to the applied electric signals, so that in the telefacsimile art the recording is effected by those signals acting on and causing the removal of successive elemental areas, Ifor eX- ample, of about 0.01 square inch each, of that coating.

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Heretofore, the masking coating had its color contrast with the black under surface, by the incorporation in the former of a conventional white pigment such as titanium dioxide, zinc oxide, zinc sulfide, lithopone, copper thiocyanate, photo-conductive phosphors, electricallyconductive zinc oxide, and the like, in its binder such as cellulose esters or ethers, acrylic resins, polyvinyl chloride-acetate resins, polyvinyl butyral resins, etc.

These prior recording blanks depend for their operation on the electrical field of the signal voltage applied to the stylus attaining a value such that electronic breakdown of the coatings occurs or the coating may be removed and the signals effect -made visible as a result of the thermal degradation of the coatings; or both the phenomenon of electronic breakdown and thermal degradation may operate simultaneously.

In order to give some divergence to the electrical field at the point of the stylus it was found necessary for good signal reproduction to incorporate in the masking coating a pigment having slight electrical conductivity. This was done by using the photoconductive phosphors, light colored semiconductor pigments, electrically-conductive zinc oxide, and meta-stable compounds like mercuric sulfide.

While coatings containing pigments of this type function well in some applications, recording blanks made using them give very poor results or are inoperative when used on equipment of the multiple styli type. For example, signals impressed on two or more adjacent styli simultaneously do not record. Then also, decomposition products collect back from the styli tips during the recording process. These undesirable products eventually accumulate to the extent that they bridge the gap between adjacent styli, resulting in poor signal response or complete failure.

It was found that (l) much clearer and sharper recordings are provided, and particularly in facsimile systems using a plurality of styli, and that failure to obtain recordings between adjacent styli is avoided and other disadvantages are overcome, by the recording blank of the invention, in which blank (a) there is dispersed in its masking layer finely divided particles of (i) one or more ferroelectric and/or ferromagnetic materials, or (ii) these ferroelectric and/or -ferromagnetic materials together with a quantity of an electrically nonconducting pigment such as zinc oxide or sulfide or others as exemplified hereinabove, and (b) that layer overlies an electrically conducting layer composed of a continuous film or sheet having dispersed in it electric conducting material such as finely divided carbon or carbon black; and (2) considerably reduced collection of breakdown products occurs on the styli.

Thus, a feature of the invention is its making available an improved recording blank which responds to stylus applied signals to yield much clearer and sharper recordings, and particularly in systems employing multiple styli such as printing apparatus wherein the styli form characters as a matrix of dots produced by an electric field or passage of an electric current through the blank. These multiple styli may be arranged uniformly spaced in a single row -or in two or more rows in any desired spacing pattern between rows.

A further feature of this invention is its provision of a recording blank or sheet which yields clear and sharp fine dots from signals impressed upon selected styli (arranged in columns or rows) with little or no irregularity in the form of the individual dots even though a signal may be impressed simultaneously upon two adjacent closely spaced styli.

A further feature is its provision of a recording blank having a masking coating whose decomposition products produced during the recording on the blank have a greatly reduced tendency t-o collect on the recordin-g styli, so that they thus avoi-d interfering with the resolution and accuracy of the recorded subject m-atter.

Still another feature of the invention lies in its recording blanks which are made up of one or more electrosensitive coatings and/or layers which retain their chemical, physical and electrical properties regardless of changes in the ambient atmosphere.

Yet a further feature of the invention resides in its novel facsimile record-ing blank comprising a carrier or supporting base or web of paper, cardboard, foil, or similar sheet material, on which is deposited one or more continuous layers or coatings of a film-forming plastic or resin or elastomer, having incorporated in it electrically conductive particles and over which is applied a single white or light colored layer or coating containing a ferroelectric and/or ferromagnetic material, or mixtures of either or both of these high dielectric constant materials.

The ferroelectric materials are defined herein as materials having the perovskite structure, visualized as a spacefilling array of truncated cubes and octahedra, and exemplified by barium titanate, calcium titanate, strontium titanate, the high dielectric constant zirconates, gallates, colombates, and tantalates, or mixtures of any of them, etc.; and characterized by their having a dielectric constant of from about l0 to about 10,000.

The ferromagnetic materials are defined herein as materials having crystalline structure similar to that of the mineral spinel derived lby replacing the ferrous ion of magnetite with any of the divalent ions magnesium, manganese, cobalt, nickel, copper, zinc or cadmium, etc.; and may consist of mixtures of two or more of these individual ferrites; and are characterized by their having a dielectric constant of from about l to about 500,000.

Although one should not be held to any particular theory as to the operation of the masking coating included in the invention, it is believed that the effect of the alternating field of the carrier signal on the masking dielectric layer of ferroelectric and/or ferromagnetic material causes a current to flow as a -result of periodic displacement of the dipole charges on that material. This displacement current may be considered to be directly proportional to the dielectric constant of the dielectric layer, under a given field strength and frequency.

A masking coating, made according to the invention, with a ferroelectric or ferromagnetic material having, for example, a dielectric constant of say 5,000 gives very good recording results. It is difficult to say what the minimum dielectric constant should be for optimum results. That is so because it is difficult to prepare such coatings formulated to an exact value, and also results depend on the carrier frequency used. It appears, however, that the minimum value for the dielectric constant of the masking coating for good results is much greater than 8, exceeds 9 and is of the order of l0 when used with a carrier frequency of 15,000 cycles per second. One skilled in this art readily can conduct the necessary tests to select a formulation from within the scope of the disclosure herein and its various examples to compound a suitable masking coating formulation and from it to prepare such a coating to approach the approximately optimum results for the specific carrier frequency to be used in a particular operation.

Direct current pulses impressed upon styli in contact with masking coatings of this invention also will result in good signal response, provided the coatings are applied to an electrically conductive base sheet; or if applied to a base conductive coating on a nonconductive support, a ground connection to the conductive coating must be made for best results.

The recording blanks of the invention are illustrated by, but not restricted to, the several embodiments shown in vertical cross-section in the first four of the accompanying drawings wherein:

FIG. l exemplifies a broad form having an electrically conducting paper 10 or base sheet as its carrier support and adheringly applied on its upper surface the masking coating 12;

FIG. 2 is a modified form of that FIG. 4l, by having separate conducting layer 11 interposed between the electrically conducting paper 10 and the masking coating 12;

FIG. 3 is a modified form of that of FIG. 2, by having a nonconducting paper 14 as its base sheet or carrier support instead of the conducting paper 10 of FIG. 2;

FIG. 4 is a modified form of that of FIG. 3, by having an intermediate c-onducting coating or layer 15 interposed between its conducting coating 11 and masking coating 12; and

FIG. 5 is a schematic showing of a facsimile system employing a plurality of styli from which discharges the electric signals (from the transmitter picked up by the receiver) against an elongated recording blank 16 of this invention. The person of ordinary skill in this art knows the make-up and operation of such apparatus system using multiple styli with a so-called dry recording blank. Thus, it only need be stated that signals corresponding to the scanned intelligence to be transmitted go from the transmitter to the receiver and in turn through usual conductors to the respective individual styli 17, corresponding to what is being transmitted at each different instant, and with the resulting corresponding dots being formed in the masking layer 12 of the recording blank 16 as it moves past the styli 17 at its set rate in synchrony with the sending rate from the transmitter.

'Many of the ferroelectric materials applicable in the improved masking coating or layer of the recording blanks of the invention have a light enough color to provide adequate contrast with the various finely divided carbon or carbon black containing conductive coatings or layers, for such ferroelectric material to be used as the sole particulate ingredient of the masking layer. However, some of the ferroelectric materials have too dark a color and most of the ferromagnetic materials have a very dark hue, so that a masking coating made from such darker materials may not provide adequate contrast in use.

Any inadequate contrast from such relatively too dark ferroelectric and/or ferromagnetic materials can be enhanced and its inadequacy overcome by incorporating with them a quantity of an electrically nonconducting white or other light colored pigment, such as zinc oxide, zinc sulfide, or titanium dioxide, sufficient to form an adequately lighter colored blend that will provide a sufficiently light colored masking coating which will yield adequate contrast.

The generally dark color of the ferromagnetic materials would appear to restrict somewhat their use in a masking coating for a recording blank of the invention, due to inadequate contrast when they are to be used alone. However, such restriction is offset to a large extent by their generally much higher dielectric constant so that considerably less of such ferromagnetic material would be required for a given result.

Such initially indicated restriction is offset further by the earlier above described blending with a white or light colored pigment. Thus, facsimile recording blanks of the invention having good recording properties can be made even with as little as 5% of such ferroelectric or ferromagnetic material in the blend with such nonconductive pigment. In some instances a dark ferromagnetic material might be blended with a suitable amount of some adequately lighter ferroelectric material. However, such recording blanks with very satisfactory recording properties have been made with very much higher content of the ferroelectric material in any such blend and even with of the particulate particles in the masking coating being ferroelectric material.

The various embodiments and modifications of the recording blank of the invention can be prepared by methods known to those of ordinary skill in this art, for example, as by the methods described in my U.S. Patent 2,664,043 (particularly its columns 3-8) including the preparation of the masking layer or coating. Such latter can be prepared by the steps of the method procedure for the masking coating in that patent (last paragraph of each of its columns 5 and 6 and first paragraph of column 7). That patent describes also methods of adheringly applying the various layers or coatings over one another and to a suitable backing web or support or carrier sheet, as well as applicable coating weights to be used.

Thus, formulations for preparing the masking coatings of the recording blanks of the invention, by the just above indicated procedures, are illustrated by, but not restricted to, the following:

Example 1.-Masking coating formulation Weight (lbs.) Barium titanate (ferroelectric: 63.7% BaO, 33.2%

TiO2, dielectric constant 1200 at 1000 cycles/sec.) 130 Zinc sulfide 50 Zinc oxide (particle size 0.25 micron) 50 Nitrocellulose, 1/2 sec. viscosity 25 Ethylcellulose, 10 centipoises viscosity 20 Tricresyl phosphate 35 Solvent (30% butyl acetate, 50% toluene, 13%

ethanol, 7% butanol) 200 Example 2.--Masking coating with quite high dielectric constant ferroelectric material Barium strontium titanate (ferroelectric: cation content 79% barium, 21% strontium; dielectric constant 8500 at 1000 cycles/sec.) 30 Zinc sulfide 10 Polyvinyl butyral (approximate mol. wt. 10,000) 6 Methanol 120 Example 3.-Masking coating with quite high dielectric constant ferroelectric material, Without color diluting pigment Barium strontium titanate (ferroelectric: cation content 79% barium, 21% strontium; dielectric constant 8,500 at 1,000 cycles/sec.) 45 Polyvinyl butyral (approximate mol. wt. 10,000) 6 Methanol 120 Example 4.-Masking coating with very high dielectric constant ferromagnetic material in a latex system Zinc ferrite (ferromagnetic material: dielectric con- The foregoing examples, and suitable modifications of them within the scope of the disclosure, are applicable for the preparation of masking coatings including ferroelectric and ferromagnetic materials, according to this invention. However, use of these high dielectric constant materials is not to be confined solely to the masking coating. As part of the invention, any of these ferroelectric and ferromagnetic materials and mixtures of any of them can provide even somewhat superior recording results, compared to those obtained from their use in the top or masking coating alone, when they are included along with the carbon or carbon black used in a so-called intermediate or second conductive 0r conducting coating the recording blank, similar to the intermediate or second such coating disclosed in my aforesaid U.S. Patent 2,664,043 (as in its column 4 first full paragraph).

Example 5 Weight (lbs.) Zinc ferrite, cobalt ferrite (ferromagnetic material:

dielectric constant 400,000 at 1,000 cycles/sec.) 30 Acetylene black 3 Vulcan C (carbon black product of Cabot Corp.) 20 Butyl methacrylate polymer (product of E. I. du

Pont de Nemours Co.) 200 Toluene 1000 The specific ferroelectric titanate of any of the preceding Examples l, 2 and 3 can be replaced in part or as a whole by a correspondingly equivalent quantity of any other such high dielectric constant alkaline earth (magnesium being included with them) titanate such as calcium and/or strontium titanate, or by any other high dielectric constant ferroelectric material having a dielectric constant of at least about 10, for example, such zirconate, gallate, colombate, or tantalate, or others, or mixtures of any of them, or by any such ferromagnetic materials as any of the type hereinabove described or disclosed, for example, any ferrite such as those used in either of the Examples 4 and 5.

Likewise, the specific ferromagnetic ferrite of either of Examples 4 and 5 can be replaced in part or as a whole by a correspondingly equivalent quantity of a single or mixed ferrite such as any hereinabove described or specifically disclosed, or of any other high dielectric constant ferromagnetic material having a dielectric constant of at least about l0, or similarly by any ferroelectric material having such dielectric constant.

Then too, the nonconductive pigment zinc sulfide, or mixtures of it and zinc oxide, of any of these examples, can be replaced in part or as a whole by a quantity sufiicient to give the needed or desired contrast, of any other compatible nonconductive light colored to white pigment such as any specifically disclosed or broadly described hereinabove, or even by a light colored to white conducting pigment so long as the ferroelectric and/or ferromagnetic material is present to the extent of at least 5% of the particulate content of the coating so as still to provide the herein disclosed effect of its high dielectric constant character.

In like manner, any of the film-forming materials such as the specific polymer or plurality of polymers of any of the Examples 1 through 5 can be replaced in part or as a whole by any other compatible suitable film-forming material, so long as the proportion of content of the high dielectric constant material and any contrast-improving pigment admixed with it to the film-forming material is such as to provide a suitably fluid and suliiciently spreadable coating mixture with the particular solvent or dispersing liquid used to apply a sufiiciently adherent continuous coating layer; all as more fully explained in the above referred to portions of my U.S. Patent 2,664,043.

In the same way, the plasticizer tricresyl phosphate of Example 1 or the dispersant of Example 4 can be used when needed and compatible in any of the other examples, or can be replaced in part or as a whole by any other respective and compatible plasticizer and/or dispersant.

Then by selecting the desired backing or support base or sheet and applying to it the desired masking coating if the backing base is, for example, a conducting paper, or whether it is conducting or nonconducting, applying over it in sequence the desired arrangement of respective conducting coating or coatings and final masking coating, there are prepared by the procedure described in the aforesaid U.S. Patent 2,664,043, the following illustrative, but not to be considered as limiting, examples of recording blanks:

(i) A recording blank having a conductive paper supporting base with particulate carbon black incorporated in it, and adhesively superposed on one of its surfaces a masking coating such as that of any of the Examples 1 through 4 or of any of the described modifications of them.

(ii) A recording blank having as its supporting base a continuous sheet or web of the conducting paper, as used in the just preceding example, and sufficiently adhesively applied to one of its surfaces any carbon black containing conducting coating such as any shown in U.S. Patent 2,664,043, and similarly adhesively applied to the latter a masking coating of any of the examples 1 through 4 or the described modifications of any of them.

(iii) A nonconducting supporting base such as a relatively thin but sufiiciently strong sheet or web of nonconducting paper or plastic film, and similarly applied to one of its surfaces a conducting coating such as described in the just preceding recording blank, and applied to the outer surface of the latter a masking coating of any of the Examples l through 4 or of any of the described modifications of any of them.

(iv) A nonconducting supporting base such as that used in the just preceding recording blank, and applied to one surface of it a conducting coating such as described in the same preceding blank, applied to the outer surface of the latter an intermediate conducting coating of relatively similar composition to that of any described in said Patent 2,664,043; and applied to the outer surface of the latter a masking coating such as that of any of the Examples l through 4 or any of their various indicated modifications.

(v) A recording blank can be prepared by replacing the intermediate conducting coating of the just preceding example (iv) by a conducting coating having incorporated in it high dielectric constant material, such as that of Example 5 or any of the various described possible modifications.

What is claimed is:

1, A multilayer recording blank responsive to stylus applied electric signals, which comprises:

(i) a layer rendered electrically conductive by having a sufficient amount therefor of electrically conductive carbon incorporated in it, and

(ii) adherently affixed to one surface of said electricall ly conductive layer a masking coating layer comprising:

(a) a such layer-forming organic material prone to breakdown responsive to said stylus-applied signals at their points of application, and

(b) incorporated in said layer-forming organic material nely divided metal compound particles from about 5 to 100 percent of which is dielectric material selected from ferroelectric material, ferromagnetic material, or mixtures of any of them; said finely divided particles being so proportioned to the layer-forming material to enable it to maintain its continuity and adherence to said electrically conductive layer and also to provide a readily visually discemable contrast with the dark appearance of said masking layer at its respective breakdown points after application of electric signals thereto; and when said dielectric material is less than 100 percent of said particles, the balance is a pigment different from said dielectric material.

2. A recording blank as claimed in claim 1, which includes solely (i) said masking coating and (ii) the electrically conductive layer and the latter is the backing support sheet of said recording blank.

3. A recording blank as claimed in claim 1, which includes solely (i) said masking coating, (ii) said electrically conductive layer as the backing support sheet of said blank; and (iii) an electrically conductive coating Ibetween (i) and (ii).

4. A recording blank as claimed in claim 1, which includes solely (i) said masking coating, (ii) an electrically nonconductive layer as the backing support sheet of said blank; and (iii) said electrically conductive coating between (i) and (ii).

5. A recording blank as claimed in claim 4, which has (iv) an intermediate electrically conductive coating between its masking coating and its electrically conductive coating.

6. A recording blank as claimed in claim 5, wherein said intermediate conductive coating also contains a quantity of dielectric material selected from ferroelectric material, ferromagnetic material, or mixtures of any of them.

7. A recording blank as claimed in claim 1, wherein the dielectric material is a ferroelectric.

8. A recording blank as claimed in claim 7, wherein said ferroelectric material is an alkaline earth titanate.

9. A recording blank as claimed in claim 8, wherein said titanate is a barium titanate.

10.' A recording blank as claimed in claim 9, wherein the ferroelectric material is barium titanate.

11. A recording blank as claimed in claim 9, wherein the ferroelectric material is barium strontium titanate.

12. A recording blank as claimed in claim 1, wherein the dielectric material is a ferromagnetic material.

13. A recording blank as claimed in claim 12, wherein the ferromagnetic material is a ferrite.

14. A recording blank as claimed in claim 13, wherein the ferrite is zinc ferrite.

15. A recording blank as claimed in claim 1, wherein the different pigment material is electrically nonconductive.

16. A recording blank as claimed in claim 15, wherein the different pigment material is selected from zinc oxide, zinc sulfide, titanium dioxide, copper thiocyanate or lithopone, or mixtures thereof.

17. A recording blank as claimed in claim 16, wherein said pigment material is a mixture of zinc oxide and zinc sulfide.

18. A recording blank as claimed in claim 17, wherein the dielectric material is a ferroelectric material.

19. A recording blank as claimed in claim 18, wherein the ferroelectric material is an alkaline earth titanate with a dielectric constant of at least 10.

20. A recording blank as claimed in claim 19, wherein the titanate is a barium titanate.

21. A recording blank as claimed in claim 17, wherein the dielectric material is a ferromagnetic material.

22. A recording blank as claimed in claim 21, wherein the ferromagnetic material is a ferrite.

23. A recording blank as claimed in claim 22, wherein the ferrite is zinc ferrite.

24. A multilayer recording blank responsive to stylus applied electric signals, which comprises:

(ii) adherently aixed to one surface of said electrically conductive layer a masking coating layer comprising:

(b) incorporated in said layer-forming organic material finely divided metal compound particles of dielectric material selected from ferroelectric material, ferromagnetic material, or mixtures of any of them; said finely divided particles being so proportioned to the layer-forming material to enable it to maintain its continuity and adherence to said electrically conductive layer and also to provide a readily visually discernable contrast with the dark appearance of said masking layer at its respective breakdown points after application of electric signals thereto.

25. A system for recording marks and characters from facsimile signals transmitted by a facsimile transmitter scanning such .marks and characters to be transmitted, which system comprises a facsimile receiver having at least one stylus for applying from its tip electrical discharges provoked by said signals, a cathodically grounded surface capable of supporting a recording blank thereon, and supported on said surface a recording -blank as claimed in claim 23 and with its masking coating facing said at least one stylus and with the tip thereof adjacent said surface to enable electric signals applied therefrom to breakdown the organic material of said coating at localized areas thereon corresponding to like areas on the material being transmitted.

References Cited UNITED STATES PATENTS 2,643,130 6/1953 Kornei 346-135 X 2,664,044 12/ 1953 Dalton 117-69 X 2,941,901 6/1960 Prill et al. 346-135 X 3,007,807 11/1961 Radocy 117-66 3,139,354 6/1964 Wolff 252-62.62

ALFRED L. LEAVITI, Primary Examiner.

ALAN GRIMALDI, Assistant Examiner.

U.S. Cl. X.R.