US3017297A

US3017297A - Smudge-resistant pressure-sensitive transfer sheet and method of making

Info

Publication number: US3017297A
Authority: US
Inventors: Douglas A Newman; Harold F E Dixon
Original assignee: Columbia Ribbon and Carbon Manufacturing Co Inc
Current assignee: Columbia Ribbon and Carbon Manufacturing Co Inc
Priority date: 1957-10-11
Filing date: 1959-09-09
Publication date: 1962-01-16
Anticipated expiration: 1979-01-16
Also published as: US2912344A

Description

1962 D. A. NEWMAN ET AL 3,017,297

SMUDGERESISTANT PRESSURE-SENSITIVE TRANSFER SHEET AND METHOD OF MAKING Original Filed Oct. 11, 1957 ADHESIVE 1 7 LAYER TRANSFER H420 LOW wuss/v5 P/G'M'ENT LAYEZ J] FOUNDAT/UA/ 2 IMAGE HARD, Law ADHESIVE 5d P/GMENT LAYER.

ADl-IEZSIVE 74 LAYER copy SHEE' INVENTORS Douglas A.Newrr7arz gfarold EEC Dixon ATTORNEY? United States atent SMUDGE RESISTANT PRESSURE SENSITIVE TRANSFER SHEET AND METHOD OF MAKING Douglas A. Newman, Glen Cove, and Harold F. E. Dixon, Douglaston, N.Y., assignors to Columbia Ribbon & Carbon Manufacturing Company, Inc., Glen Cove, N.Y.. a corporation of New York Original application Oct. 11, 1957, Ser. No. 689,635, now Patent No. 2,912,344, dated Nov. 10, 1959. Divided and this application Sept. 9, 1959, Ser. No. 838,921

13 Claims. (Cl. 117216) This invention relates to transfer writing and particularly to the placing of marks and indicia by means of printing or writing pressure or a type blow, acting through a pressure-sensitive transfer sheet of the carbon paper type.

The present application is a division of application Serial No. 689,635 filed October 11, 1957, now Patent No. 2,912,344 granted November 10, 1959.

Transfer sheets of the carbon paper type have, of course, been known and used for many years. Lately, however, the placing of various types of record marks on copy sheets or cards to be handled and sensed by data processing equipment has become a matter of increasing interest, and the use of carbon paper sheets or typewriter ribbons as the medium for placing spots of the required properties has been suggested, one such suggestion appearing in the patent to Mumma, No. 2,744,031.

It has been found, however, that most of the pressure transfer layers, as currently prepared, are lacking in certain respects when an attempt is made to adapt them to data processing use. While the marks made are of adequately permanent nature considered in the sense of ordinary carbon copy use and will remain sufficiently legible under most conditions, it has been found that there is a slight tendency to smudge and spread if the marked sheet is handled a great deal, or used with the ordinary sheet or card feeding and handling equipment encountered in data processing machinery. Also, in conventional practices, it is difiic'ult to control the smudging of the copy sheets or cards in the transfer process due to the dirty surface of the transfer sheets. When this smudging occurs, the reliability with which the true mark can be automatically sensed is severely impaired, even though the impairment is sometimes comparatively slight by visual standards, and false indications are picked up due to contact of the dirty, uncoated surface of the transfer sheet with the record caused by handling during the transfer process.

The objects of the present invention are to provide a transfer element which is smudge-free and clean to the touch, has excellent adhesion, even for greasy surfaces, and is of such character that the transferred spot or image when formed will be substantially proof against smudging and such that the marked card or sheet will pass readily through ordinary handling equipment without the spots sustaining any change sufficient to affect the accuracy of the sensing operation.

It is a feature of the present invention that the foregoing objects are brought about by constructing the transfer sheet with a coating having at least two distinct layers or strata, simultaneously transferable from the carrier sheet in a substantially stenciling fashion, in which both the bottom stratum or layer nearest the carrier sheet and the top layer have smudge-resistant properties. These properties of smudge-resistance are due to the absence from the top layer of material to which the sensing device will react, so that even though the top layer is partially displaced by handling, the displaced portion will not affect the sensing means, or to the char! acter of the bottom layer as being relatively hard and ice of low adhesiveness so that, even though charged with a type of material to which the sensing device in question will react, it is not subject to ready displacement from the spot where applied.

By reason of the placement of the bottom smudgeresistant layer adjacent the carrier sheet, the image formed when the coating is transferred by pressure from the carbon paper to the copy sheet has an exposed surface which normal contact with handling devices does not seriously affect, so that, even though the sheet has been fed and handled, there is assured a reaction at the sensing means which is the same as that which the spot would have brought about in its freshly-transferred condition.

It will be readily appreciated that the principles of the invention can be applied whether the transfer layers are arranged to deposit spots suitable for sensing visually or by photoelectric means, by magnetic means, by electrical contact means, or by any other means sensitive to special material in the coating. Examples of various types will appear as the description proceeds.

In the drawing:

FIGURE '1 is a fragmentary diagrammatic section to an enlarged scale of a pressure-sensitive transfer element according to one form of the invention.

FIG. 2 is a fragmentary diagrammatic section to an enlarged scale of a copy sheet having thereon a spot formed by transfer from the element of FIG. 1.

Referring to the drawing, the transfer element of the present invention comprises a carrier sheet or strip 11 of paper, regenerated cellulose, cellulose acetate, or a' similar thin, flexible material. Onone surface of the sheet or strip 11 is formed a transfer coating 13 which is characterized particularly by the fact that it is made up of two strata or

layers

15 and 17. The base layer 15 which lies next to the carrier 11 and the top layer 17 are both layers of material having smudge-resistant properties as hereinbe-fore mentioned and defined. The base layer has placed on its surface the top layer 17 which is so constituted as to firmly bond to the base layer 15. The

layers

15 and 17 are somewhat commingled adjacent their meeting surfaces to effect this bond, as indicated by the character of the cross-hatching in FIG. 1. The nature of the

composite layer

15, 17, Le. the coating 13, is such that when the carrier 11 is impressed by a stylus or struck by a type, substantially all of the material of coating 13 in the area pressed or struck will be transferred to an adjacent copy sheet, leaving little, if any on the transfer carrier. In other words. the coating has the property known in the art as stenciling. The dual character of the coating 13 lends itself very well to this purpose since the layer 15 as formulated is relatively hard and has a particularly low degree of adhesiveness for the carrier 11 to promote ready release under pressure without division of the coating, and the layer 17 is formulated to have a more pronounced adhesiveness for the copy paper or receiving sheet normally used whereby to bring about the stenciling transfer. While, in most cases, it is preferable to have the layer 15 separate from the foundation 11 almost entirely, this is not always essential, and the term stenciling is understood to include cases where only a portion of layer 15 may be transferred, so long as it is sufficient to be effective for the purposes intended.

The FIG. 1 form is at present found most useful in systems employing visual reading, or for automatic photoelectric or magnetic sensing. For visual use or for photoelectric sensing a pigment having light reflecting or absorption value is carried in the bottom layer 15, and the same would be so colored as to contrast sharply with the color of the cards or copy sheets on which it is to be used. Carbon black, for example, would serve 'elfeetively if used on light colored cards. In one embodiment of the present invention the layer 17 is compounded with little or no pigment so as to be substantially transparent. Another embodiment of the present invention comprises the addition of a tint color to the top layer 17 which together with the dark pigment of the bottom layer 15 gives an overall lightened color to the transfer paper. However, on transference the colors apparently coalesce under pressure and the tone of the stronger pigment of layer 15 is emphasized yielding a stronger colored copy than would have been expected from the light appearance of the transfer sheet. Here, for instance, a blue pigment or a pink pigment may be included in the layer 17 and a black or red color in layer 15, respectively. The final transfer paper then has a light colored appearance, but upon transfer under pressure the dark black or red copy predominates to give a strong colored copy.

When the pressure transfer has been effected in the normal way, a product as seen in FIG. 2 will result, having an image 23, the bottom layer 17a, previously the top layer of the transfer sheet, lies against and is adhered to a copy sheet 21, and the top layer 15a, which was previously the bottom layer of the transfer sheet, is exposed at the surface. It will be seen that the layer 15a is bonded by the adhesive layer 17a effectively to the copy sheet. Layer 15a is itself not soft enough to be disturbed or spread by random contact with feeding or handling devices, or so hard as to be substantially impervious to such spreading, and the layer 17a remains in its original position precisely as placed. Because the layer 15a is hard enough to resist displacement, it is clearly compounded to be smudgeresistant as the term is defined above and used throughout this description.

Included in the term pigment, of course, are pulverulent materials of all kinds whether used for their light response or not. In case the pigment is of magnetic particles, iron oxide for example, the image or mark 23 will be capable of being sensed by magnetic pick-up means, and in this instance the layer 17a may also be pigmented with a tint color if desired, so long as the pigment used is non-magnetic.

FIG. 1 illustrates a form of the invention in which a carrier sheet 11 carries a coating 13 including a 'base layer 15 and a top layer 17. The base layer 15 is so constituted that if and when exposed to normal abrasion and rubbing it will not be displaced or spread. This means that the mixture is compounded to be relatively hard and, in the dry state, to have a low degree of tackiness or of adhesiveness for most other surfaces. When applied, it is rendered fluid by reason of heat or a volatile liquid dispersion medium, so that in drying and setting either by cooling or evaporation it attaches itself to the carrier sheet with tenacity sufiicient for ordinary purposes, and will readily release therefrom. The base layer 15 includes a pigment intermixed therewith, which may be of the types heretofore mentioned which are sensed with light-responsive or magnetic means. In addition, in this form a properly compounded coating which includes electroconductive pigmentary material, e.g. silver powder, aluminum powder, or finely divided graphite, may be used to actuate eventuallyan electric sensing means, e.g. by closing a circuit between feeler brushes.

Inasmuch as the layer 15 is prepared so as to be hard and normally to have low adhesiveness for other surfaces, it will not ordinarily transfer particularly well by itself under most conditions. The top layer 17 is applied thereover and is so compounded as to be somewhat softer and more adhesive than the layer 15. It will be thoroughly connected, to layer 15 in the manner heretofore explained and will provide a surface having sufi'lcient adhesiveness to cause local pressure transfer to a receiving copy sheet, taking theadjacent portion of layer 15 with it. It is largely immaterial whether layer 17 has pigment or not, but pigment may be included for the purpose of masking or 4 intensifying the ffect of the pigment used in the layer 15 if desired.

When pressure transfer has been effected in the normal way, a product as seen in FIG. 2 will result, having an image or mark 23, the pigmented layer 15a of which is on the exposed surface. This layer, however, is of such a hard, non-adhesive character that it will resist normal abrasion or contact displacement, and hence is smudgeresistant, even though containing the pigment to be sensed. The layer 17a next to the copy sheet firmly anchors the entire mark 23 in place.

If the pigment used to prepare the layer 15 is electroconductive, the layer is also preferably compounded using ingredients which will render the particles mutually contacting so that a continuing conductive relationship extends throughout the layer. Illustrative examples of mixtures suited to this purpose are as follows:

(Formula 1) Base layer:

Examples of mixtures suitable for preparing a transfer sheet in accordance with FIG. I are as follows:

EXAMPLE I Base layer: Formula 1 or 2 as given above. (Formula 3) Top layer:

Ingredients Parts by weight Carnauba wax 45 .0 Indopol H-300 (Tacky viscous liquid mixture of polymerized butene isomers) Beeswax 6.0 Mineral oil 20.0 Pigment, if desired 10.0 to 20.0

Example I represents a coating for producing spots 23 especialy for sensing by electrical contact means.

EXAMPLE II (Formula 4) Base layer:

Ingredients- Parts by weight Carnauba wax 45.0 Ceresin 4.0 Lanolin 6.0 Mineral oil 15.0 Carbon black 12.0

Top layer: Formula 3 as given above.

Example II represents a coating for producing spots 23 especially for sensing by light-sensitive means.

EXAMPLE III (Formula 5) Base layer:

Ingredients- Parts by weight Carnauba Wax 45.0 Ceresin 4.0 Lanolin 6.0 Mineral oil 15.0 Magnetic iron oxide 18.0

Top layer: Formula 3 as given above. Example III represents a coating for producing spots 23 especially for sensing by magnetic means.

The coatings of Examples 1 to III are formulated for use particularly in connection with carrier sheets of carbonizing kraft, but the base layer formulation may be suitably varied as previously indicated to provide for use with carrier sheets of a smooth film if desired.

It will be understood that the examples given above are illustrative only and that various types of formulations may be employed within the scope of the present invention. For example, the compositions for the various layers may be compounded as resinous base mixtures rendered fluid for coating by being suspended in volatile solvent. liquids as shown in copending application Serial No. 503,830, filed April 25, 1955, and now abandoned, and in US. Patents No. 2,872,340 issued February 3, 1959, and No. 2,810,661 issued October 22, 1957. In this connection it should be pointed out that, in general, the layers cast from a mixture of a resinous base sus pended in volatile solvent, when properly compounded, perform especially well as the layer 15 which is designed to be resistant to mechanical spreading or displacement. Among the tackifying synthetic resinous adhesives which may be substituted for the polymerized butene mixture in Formula 3 supra are known adhesives such as plasticized polyvinyl chloride, plasticized polyvinyl chloridevinyl acetate copolymers, vinyl ethers such as polyvinyl methyl ether and polyvinyl isobutyl ether, polyvinyl alcohol, and the butadiene rubber copolymcrs such as of styrene and acrylonitrile (Buna N and Hycar OR), as well as others.

Integration of the layers at the interface may be effected by various suitable treatments, such as the softening of the surface of the base layer by solvent treatment just prior to depositing the top layer, or preferably by subjecting the coated sheet to controlled heating or fusion just after the top layer has been placed.

From the foregoing description it can be seen that a novel coated, smudge-proof, clean handling, pressure-sensitive transfer element of the carbon paper type has been provided in which the coating comprises a base layer and a top layer which are simultaneously transferable in stenciling fashion from the carrier to an adjacent copy sheet, and in which the base layer 15, by virtue of its properties of hardness and resistance to mechanical displacement, is thoroughly smudge-resistant. A transfer element of this character is capable of producing novel images and spots in which the transfer sheet layers are inverted and which have excellent properties of adhesion, even for greasy or dirty surfaces, and accordingly have a high degree of resistance to smudging so as to perform reliably in data processing equipment in spite of the feeding and handling to which they will normally be subjected prior to sensing. Thus, in the case of the processing of checks or receipts which are greasy or oily due to being handled and carried by factory Workers or mechanics, etc., the transfer papers of the instant invention furnish excellent properties of adhesion for the greasy surfaces and insure that the images transferred will not flake ofl.

The term sheet as used herein applies to flexible foundation membranes of any sort in coated or uncoated condition, whether of limited length or of extended length, and in this connection includes items sometimes referred to as webs, strips, or ribbons.

Variations and modifications may be made within the scope of the claims and portions of the improvements may be used without others.

We claim:

1. As a new article of manufacture, smudge-resistant pressure-senstive transfer element of the carbon paper type comprising a flexible foundation sheet having thereon two mutually adhering layers which are simultaneously locally transferable from the foundation to a copy sheet in a substantially stenciling manner in response to a blow or pressure, the base layer adjacent the surface of the sheet having readily releasable contact therewith and being so compounded as to be relatively hard and to have low adhesive properties whereby to resist strongly displacement due to normal physical contact with other articles, and being charged with pigment designed for automatic sensing, and the top layer being integrated with the surface of the base layer and having adhesive properties both for a copy sheet surface and for said base layer to effect local transfer thereof when desired.

2. As a new article of manufacture, a smudge-resistant pressure-sensitive transfer element of the carbon paper type comprising a flexible foundation sheet having thereon two mutually adhering layers which are simultaneously locally transferable from the foundation to a copy sheet in a substantially stenciling manner in response to a blow or pressure, the base layer adjacent the surface of the sheet having readily releasable contact therewith and including a pigment designed for automatic sensing, and being sufliciently tenacious and free from adhesiveness to be normally, of itself, non-transferable under a blow or pressure, and the top layer being integrated with the surface of the base layer and being of tacky, adhesive, smudge-resistant character whereby to provide for local transfer of said base layer and carry the same with it at the time of its own transfer.

3. A record-carrying element for use with automatic sensing equipment comprising a foundation sheet, and a local sensible carbon paper mark thereon containing two mutually adhering layers, the one lying farthest from the foundation being so compounded as to be relatively hard and to have low adhesive properties and transfer properties, of itself, whereby to resist strongly displacement due to normal physical contact with other articles, and being charged with pigment designed for automatic sensing, and the other layer nearest the foundation being integrated with the surface of the one layer and having adhesive properties both for the foundation and said one layer whereby said one layer is transferred and securely afiixed to said foundation.

4. A record-carrying element as defined by claim 3 in which the pigment is magnetic pigment.

5. A record-carrying element as defined by claim 3 in which the pigment is electroconductive pigment.

6. A record-carrying element as defined by claim 3 in which the pigment is photoelectrically sensitive pigment.

7. A record-carrying element for use with automatic sensing equipment comprising a foundation sheet, and a local sensible carbon paper mark thereon containing two mutually adhering layers, the one farthest from the foundation including a pigment designed for automatic sensing, and being suificiently tenacious and free from adhesiveness to be normally, of itself, non-transferable under a blow or pressure, the other layer lying nearest the foundation being integrated with the surface of the one layer and being relatively soft and adhesive and therefore subject to possible displacement, but providing for transfer to said foundation of said one layer and carrying the same with it at the time of its own transfer.

8. The method of preparing smudge-resistant pressuresensitive transfer elements of the carbon paper type which comprises coating a flexible foundation sheet with a base layer containing a pigment designed for automatic sensing, said base layer being so compounded as to be relatively hard and to have low adhesive properties whereby to resist strongly displacement due to normal physical contact with other articles, applying to the surface of said base layer a top layer having adhesive properties both for a copy sheet surface and for said base layer, and integrating said layers so that upon transfer ,to a copy sheet said top layer will carry said base layer with it.

9. The method of claim 8 in which integration of the layers is elfected by treating the base layer with a solvent prior to applying the top layer.

10. The method of claim 8 inwhich integration of the layers is effected by subjecting the coated sheet to controlled heating after the top layer has been applied.

11. The method of preparing smudge-resistant pressure-sensitive transfer elements of the carbon paper type which comprises coating a flexible foundation sheet with a base layer containing pigment designed for automatic sensing, said base layer being suificiently tenacious and free from adhesiveness to be normally, of itself, nontransferable under a blow or pressure, coating said base layer with a top layer having tacky, adhesive, smudge-resistant properties, and integrating said layers whereby to provide a transfer element in which the top layer is pressure-transferable and carries with it at the time of its transfer said normally non-transferable base layer.

12. The method of claim 11 in which integration of the layers is efiected by treating the base layer with a solvent prior to applying the top layer.

13. The method of claim 11 in which integration of the layers is efiected by subjecting the coated sheet to controlled heating after the top layer has been applied.

References Cited in the file of this patent UNITED STATES PATENTS 2,188,590 Bjorksten et a1 Jan. 30, 1940 2,744,031 Mumrna May 1, 1956 2,762,715 Newman Sept. 11, 1956 2,912,344 Newman et al Nov. 10, 1959

Claims

1. AS A NEW ARTICLE OF MANUFACTURE, SMUDGE-RESISTANT PRESSURE-SENSITIVE TRANSFER ELEMENT OFTHE CARBON PAPER TYPE CONPRISING A FLEXIBLE FOUNDATION SHEET HAVING THEREON TWO MUTUALLY ADHERING LAYERS WHICH ARE SIMULTANEOUS LOCALLY TRANSFERBLE FROM THE FOUNDATION TO A COPY SHEET IN A SUBSTANTIALLY STENCILING MANNER IN RESPONSE TO A BLOW OR PRESSURE, THE BASE LAYER ADJACENT THE SURFACE OF THE SHEET HAVING READILY RELEASABLE CONTACT THEREWITH AND BEING SO COMPOUNDED AS TO BE RELATIVELY HARD AND TO HAVE LOW ADHESIVE PROPERTIES WHEREBY TO RESIST STRONGLY DISPLACEMENT DUE TO NORMAL PHYSICAL CONTACT WITH OTHER ARTICLES, AND BEING CHERGED WITH PIGMENT DESIGNED FOR AUTOMATIC SENSING, AND THE TOP LAYER BEING INTEGRATED WITH SURFACE OF THE BASE LAYER AND HAVING ADHESIVE PROPERTIES BOTH FOR A COPY SHEET SURFACE AND FOR SAID BASE LAYER TO EFFECT LOCAL TRANSFER THEREOF WHEN DESIRED.