US2954311A

US2954311A - Method for copying indicia by particle transfer

Info

Publication number: US2954311A
Application number: US686242A
Authority: US
Inventors: Weel Walter H Vander
Original assignee: Individual
Current assignee: Individual
Priority date: 1957-09-25
Filing date: 1957-09-25
Publication date: 1960-09-27
Anticipated expiration: 1977-09-27

Description

P 1960 I w. H. VANDER WEEL 2,954,311

METHOD FOR COPYING INDICIA VBY PARTICLE TRANSFER Filed Sept. 25, 1957 2 Sheets-Sheet 1 FIG.

F/G'. Z 1 5 7 F 1 1 1 1 1 1 1 j 8 F/G. 3 7 I W V V V V 8 5 6 I P76. 4 (7 1 1 1 1 1 1 8, 1 /2 Q k v I 1 1 1 1 1 1 INVENTOR WALTER/i VA/VDER WEEL A from y v v flq. 2:10.

' Sept. 27, 1960 w. H. VANDER 'WE'E'L METHOD FOR COPYING INDICIA BY PARTICLE TRANSFER FIG. 5

INVENTOR.

WALTER H. 144N051? WEEL BY %A 2, Jam

A/forney United States Patent METHOD FOR COPYING INDICIA BY PARTICLE 5 TRANSFER Walter H. Vauder Weel, Ontario, N.Y.

Filed Sept. 25, 1957, Ser. No. 686,242

1 Claim. (Cl. 154-95) This invention relates to a method for rapidly making copies of indicia material such as typewritten, pencil, printed or mimeographed indicia and colored indicia such as Water color prints and hectograph copies by subjecting to heat an indicia-bearing sheet which is of opaque, translucent or transparent material juxtaposed with a copying sheet to transfer a portion of said indicia adjacent said indicia material to the surface of the copying sheet by means of particle transfer; said copying sheet then being usable for additional reproductions.

Methods heretofore employed for copying indicia have utilized a thermal copying paper which when juxtaposed with an indicia bearing sheet and exposed to infrared radiation only reproduced certain types of indicia. For example, methods heretofore have not utilized a copying paper. which was capable of reproducing colors and signatures.

Furthermore previous methods for copying indicia utilizing infrared radiation for activation have provided copies of indicia on a copying sheet but these copies have not been reproducible since the indicia of the copies do not absorb the infrared rays, convert them to heat and activate the copying sheet so that no copies of the first copies are provided.

It should also be noted that prior methods utilized for making copies of indicia have been extremely slow and have provided copies of indicia, which have had very poor image clarity.

The present invention relates to a method of rapidly making copies of indicia material from a sheet bearing indicia by subjecting to heat a sheet bearing indicia juxtaposed with 3. copying sheet to reproduce said indicia material by transferring said indicia material to said copying sheet to produce indicia on said copying sheet. Colors and signatures are also reproducible with this method; the copying sheet being utilizable for additional reproductions.

There have been heretofore proposed a variety of methods for copying indicia which utilize copying sheets having coatings thereon which provide sensitivity to thermal radiations. These methods operate by heating by means of infrared radiation a copying sheet having a coating composed of two react-ants which are light colored disposed in a light colored media to cause the reactants to react to provide a dark colored reaction product. The copying sheet may then be used with any of the known thermal copying sheets, such as those disclosed in U.S. Patents 2,663,654 and 2,663,655, by placing the indicia material of the sheet bearing indicia which is to be copied in contact with the coated surface of the thermal copy sheets and exposing to infrared radiation.

Another disadvantage exhibited by previous methods in which heat has been used to cause a copy to be made on a copying sheet has been poor contrast of indicia to copying sheets due to the color of reactants and reaction products utilized which limits the colors which may be used to those provided by such reactants and products; for example, a salmon colored surface after 30 temperature of the backing sheet and high enough not to 7 2,954,311 Patented Sept. 27, 196 0 thermal exposure changes areas to a blue-grey or dull blue-black. It is desirable to provide sharp contrast, that is, a jet black or other very dark color on the areas after heating.

The coating on copying sheets utilized in my method should be sufiiciently tacky at temperatures from 150- 350 F. to cause the coating to adhere firmly to the indicia bearing areas to pick particles from the indicia and form the-desired copy. The coating should also be tacky enough that the copying paper does not slip and provide a blurred copy. However, the coating should not be so tacky at the aforementioned temperatures that the coating of the copying sheet becomes so firmly adfixedto the surface of the indicia bearing sheet or the known thermal copying sheets that the sheets cannot be separated.

It is desirable that copying sheets utilized in the invention be free from a tendency to block, i.e., adhere at storage temperatures such as 70 to 130 F. and that they be relatively insensitive to pressure from sharp instruments of the type they are likely to undergo in handling; that is, insensitive to styli, fingernails, staplers, and other office equipment which may be sharply brought in contact with them.

In accordance with a preferred embodiment of my invention, I utilize a copying sheet which is preferably either a sheet of plasticized thermoplastic synthetic resin or a sheet of opaque, translucent or transparent material coated with a thermoplastic synthetic resin, said resin having a softening temperature below the decomposition be tacky below F. This copying sheet is juxtaposed in contact with the indicia-carrying side of a sheet bearing indicia which is desired to be copied in such a manner that a resin surface of the copying'sheet contacts said indicia; the resultant assembly of two sheets is then subjected to heat or infrared radiation to cause the resin to become softened; particles of the indicia (i.e., dye or pigment particles) adhere to the resin whereby particles from the material being copied are transferred to the copying sheet. The copying sheet may then be separated from the sheet bearing indicia thereon and if desired this copying sheet may then be used with any of the known thermal copying sheets, such as those disclosed in U.S. Patents 2,663,654, and 2,663,655, by placing the indicia material of the sheet bearing indicia which is to be copied in contact with the coated surface of the thermal copy sheets and exposing to infrared radiation to provide a copy of the first copy.

An object of the present invention is a method for copying indicia.

Another object of the invention is a method for copying colored indicia.

-Another object is a method for making a copy of a copy comprising juxtaposing a sheet having indicia thereon with a copying sheet of the type hereinafter described and exposing the assembly to heat to provide a copy of the indicia; then juxtaposing the copy of indicia with a known thermal copying sheet, and exposing the assembly to heat to provide a copy of the first copy.

Another object of the present invention is a method for copying indicia consisting essentially of juxtaposing a sheet bearing indicia with a copying sheet consisting essentially of a thermoplastic synthetic resin material or a thermoplastic synthetic resinous coating on a backing sheet and exposing the resultant assembly of two sheets to heat to reproduce the indicia of said indicia bearing sisting essentially of a thermoplastic synthetic resinous coating on a backing sheet and exposing the resultant assembly of two sheets to heat to reproduce the signature of said signature bearing sheet by transferring a portion of said signature on copying sheet to provide a copy of the signature.

Another object is a method for making a permanent copy of indicia consisting of juxtaposing a sheet bearing indicia with a copying sheet consisting essentially of a thermoplastic synthetic resin material laminated to a partially heat transparent backing sheet and exposing the resultant assembly of two sheets to heat to reproduce the indicia of said indicia bearing sheet by transferring a portion of said indicia to the copying sheet to provide a permanent copy of the indicia.

Another object is a method for making a permanent copy of a copy comprising laminating the copy of the indicia of an indicia bearing sheet to a second sheet having a color contrasted with the color of said indicia of said copy to produce a permanent copy of said indicia.

Other objects will become apparent from the drawings and from the following detailed description in which it is intended to illustrate the applicability of the invention without thereby limiting it to scope less than that of all equivalents which will be apparent to one skilled in the art; in the figures, like reference numerals refer to like parts and:

Figure 1 is a cross-sectional view of a method of the invention;

' Figure 2 is a cross-sectional view of a method of the invention;

Figure 3 is a cross-sectional View of a method of the invention;

Figure 4 is a cross-sectional view of a method of the invention;

Figure 5 is a cross-sectional View of the assembly before treatment in accordance with the method of the invention;

Figure 6 is a cross-sectional view of the copy produced by the method of the invention; and

Figure 7 is a cross-sectional view of the original indicia bearing sheet after treatment in accordance with the method of the invention.

Referring now to the drawings, there is shown in Figure 1 a method for copying indicia comprising juxtaposing a copying sheet 2 consisting of a heat transparent backing-sheet 3 which may be opaque, transparent or translucent, synthetic organic resin having coated thereon a coating 4 of thermoplastic synthetic resin, with the indicia 5 of an indicia bearing sheet 6 which may be opaque, translucent or transparent, and subjecting the resultant assembly to heat from a source located above or below the assembly, said source located above the assembly for the sake of simplicity being designated as 7, said source located below the assembly for the sake of simplicity being designated as 7. The heat softens coating 4 causing the coating to become tacky and causing transfer of a portion of particles from indicia 5 adjacent the indicia bearing areas to the tacky surface on sheet 2 to provide indicia 8 thereon, thus providing a copy sheet having indicia thereon.

The method of Figure 3 is the same as Figure l but utilizes a copying sheet 12 consisting of a synthetic resin which may be opaque, transparent or translucent.

The heating for Figures 1 and 3 may be accomplished by subjecting the assembly comprising an indicia-bearing sheet 6 juxtaposed in contact with copying sheet 2, 12 to a source of heat 7 located above the assembly so the heat passes downward thru the assembly to heat the copying sheet as a whole by means of conduction thus softening the copying sheet and causing it to become tacky to transfer the indicia from the indicia bearing sheet to the copying sheet.

Heating for Figures 1 and 3 may also be accomplished by subjecting the assembly comprising indicia-bearing sheet 6 juxtaposed in contact with copying sheet 2 or 12 to a source of heat 7 located below the assembly so the heat passes upward thru the assembly heating the copying sheet 2, 12 by convection until the copying sheet is softened and tacky to cause transfer of indicia 8 adjacent the indicia 5 of the indicia-bearing sheet 6 to the softened copying sheet 2, 12.

Heating for the methods of Figures 1 and 3 may also be accomplished by passing infrared radiation down thru the assembly shown in Figures 1 and 3, the majority of the rays from the radiation being absorbed by the pigment in the coating or by the pigment in the copying sheet 12 and converted to sensible heat to soften the coating 4 or copying sheet 12 to transfer a portion of the indicia 5 adjacent the indicia bearing areas to the tacky surface on copying sheet 2, or 12.

It is preferable that this means of heating i.e., infrared radiation not be employed for. the method of Figure 1 or if dyes are employed in the copying sheet 12 or coating 4 since optimum results are not obtained due to preferential heating in the indicia bearing areas.

Figure 2 shows the'copying sheet 2 having heat absorbent indicia 8 thereon as producedby the method of Figure 1 juxtaposed with a heat sensitive copying paper sheet 9 of the type described in US. Patents 2,663,654, 2,663,- 655 and copending application Ser. No. 644,541. The two sheets thus disposed are exposed to heat from a source of heat located above the assembly; said'source of heat indicated generally as 7 to provide copying sheet 9 with indicia 8. I

The method of Figure 4 is the same as the method of Figure 2 except that it utilizes the activated copying sheet of Figure 3 having indicia 8 thereon.

The necessary heating for the methods of Figures 2 and 4 may be produced bypassing infrared radiation indicated generally as 7 down through the assembly of copying sheet 2, 12

bearing indicia

8, 8 and known thermal copying sheet 9, the maximum number of rays from the radiation are absorbed by the

indicia

8, 8 of the indicia bearing copying sheet 2, 12 and are converted to sensible heat to soften the copying sheet and cause the surface to become tacky to cause transfer of a portion of the indicia 8, 8' adjacent the indicia bearing areas to the known thermal copying sheet 9.

Figure 5 shows copying sheet 2 consisting of a partially heat transparent backing sheet 3 and coating 4 juxtaposed with indicia 5 of an indicia bearing sheet 6 before treatment in accordance with the method of the invention.

Figure 6 shows copying sheet 2 consisting of a partially heat transparent backing sheet 3 and coating 4 with indicia 8 thereon after treatment in accordance with the ethod of the invention.

Figure 7 shows the original indicia 5 of the indicia bearing sheet 6 after treatment in accordance with the method of the invention, showing that portion of indicia 5 which was transferred to the copying sheet.

Suitable means is described in such patents as US. Patents 2,663,655 and 2,740,895 for reflecting infrared radiations from a highly heated rod or filament against a portion of both the copying sheet and the indicia bearing sheet while the sheets are passed over the rod or fila-. ments, being held in place between a belt of heat resistant synthetic resin, such as, for example, polychlorotrifluoroethylene, and suitable holding means.

Printing by themethod of the invention may be accomplished in any suitable manner; a preferred manner is to utilize a machine or any suitable device which can produce thenecessary amount of heat; the amount of heat needed being suflicient tosoften the thermoplastic synthetic resin film but not so great as to melt the thermoplastic synthetic film and cause apertures therein. General heating of the assembly comprising indicia bearing sheet and copying sheet as a whole is preferred to preferential heating in the indicia bearing areas.

Under certain conditions preferential heating in the indicia bearing areas may occur due to the presence of a pigment in the copying sheet but this is not desirable since it does not give optimum results. Heating of the sheet is preferably at a temperature of from 150 F. to 350 F.

By copying sheet utilizable-in my method, I mean a copying sheet comprisingthermoplastic synthetic resin sheets or films or backing-sheets which are opaque ortransparent coated with thermoplastic synthetic organic resinous materials which when subjected to a temperature from 150 F. to 350 F. will soften sufiiciently to allow particles from the indicia material, i.e., dye or pigment of the indicia bearingsheet to be picked up to provide acopy of the indicia.- I r I By thermal copying sheets, I mean copying sheets of the type described in US 2,663,654, 2,663,655, and copending application Ser.'No. 644,541 which when used with the copying sheet having indicia thereon will produce additional copies-on exposure to infrared radiation.

While a variety of synthetic organic resin sheets or films may be utilized to provide a copying sheetor the coating on the copying sheet suitable for my method, thermoplastic synthetic organic resinous materials are generally preferred.

A copying sheet suitable for my method is preferably a non-tacky opaque or transparent thermoplastic resin which is subjected to a minimum of heat distortion and which on subjecting to heat is capable of particle transfer of the particles from the indicia bearing sheet to the copying sheet.

A copying sheet suitable for use may be a white sheet or any color, even black; the color preferably but not necessarily contrasted with the color of the indicia which is to be copied. i The thermoplastic material which is preferred is cellulose triacetate. However, suitable results have also been obtained with vinyl compounds such as polyvinyl acetate, polyvinyl chloride, polyvinylidene chloride and copolymers therewith, polyvinyl butyral, styrene and its homologs, polyamides, acrylates and methacrylates or the like.

A preferred synthetic resin for the coating is a natural latex or latex-like composition, i.e., an emulsion cornprising an elastomeric or other polymeric synthetic resin which is preferably thermoplastic in nature. It may be necessary to adjust the materials to provide proper tack. Such apolymeric resin-may be polyvinyl chloride, polyvinyl alcohol, polyethylene, polyvinyl acetate, copolymer of vinyl acetate and vinyl chloride, halogenated polyethylene, halogenated rubb'er, hydrochlorinated rubber, natural rubber, i.e., polyisoprene, polychloroprene, polybutadiene, copolymer of any one of the last three with styrene and/or acrylonitrile, or other monomer adapted to undergo polymerization through ethylenic unsaturation. A suitable plasticizer may be included. i

A particularly suitable coating'composition has been found to be a mixture of low viscosity and low molecular weight polyvinyl acetate and chlorinated rubber dissolved in a suitable solvent such as toluene. This composition may be suitably coated on cellulose triacetate and gives a particularly suitable copying sheet used in my method 6 and the other side of the roll running against a web of paper or other sheet material. After passing over the roll, the web is then passed over a Mayer equalizer rod consisting of a rod of about one quarter inch diameter wound with wire in the form of a tight coil or helix, the wire being preferably No. 6 wire.

Tackifying agents which may be used when the thermoplastic coating does not have a suitable tack of its own include: Pliolite (a natural rubber-stwene copolymer produced by Goodyear) resins, alkyd resins and latices as well as other tackifying agents.

The coating of synthetic organic resinous material on the copying sheet utilized in my method may be clear, i.e., transparent or translucent, or it may be colored by the addition of coloring material. As a coloring agent or coloring material to be included, there may be used either a pigment or a dye; a pigment absorbs a relatively largeportion of infrared rays and converts such rays into heat whereas a dye transmits a large portion of infrared rays and absorbs and converts a minimum of such rays into sensible heat. I

If the copying sheet utilized in mymethods is to be reproduced with known thermal copy sheets, it is desirable that the coloring agent or coloring material to be included with the resin coating be a material which transmits a relatively large portion of infrared rays and which absorbs and converts substantially a minimum of such rays into sensible heat.

The extent of exposure to infrared radiation used in my method depends on the coloring matter employed in the copying sheet. When a small amount of pigment is present in the copying sheet, relatively few rays are absorbed and converted to sensible heat so that a long exposure time must be employed to soften the copying sheet sufficiently to obtain particle transfer thereto. However, if a large amount of pigment is used, a greater portion of rays are absorbed and converted to sensible heat and only because of its aging characteristics, i.e., didnt deteriorate during storage.

The formulation for the coating may be coated on a suitable support material by any suitable means; from a-solvent for example, in the case of materials for templates wherein the coating is to be applied to aluminum or steel sheet, it may be applied with a brush or by spraying or dipping. Preferably ,it is applied by means of a suitable coating technique for obtaining a thin coating of relatively uniform thickness using standard coating equipment such as a knife coater reverse roll 'coater, or the like. It is particularly suitable to coat with; atransfer roll which operates with one side of the roll dipping into a pan ofthe material to be coated a short exposure period is necessary. If large concentrations of dyes are used, however, a greater portion of rays will be transmitted, thru the assembly but some rays will be absorbed and converted to sensible heat. In order to get sufficient heat to obtain particle transfer, a very long exposure would be needed.

Suitable dyes which may be utilized include, for example, for a green color, a mixture of 10% Iosol Yellow (National Aniline Company) plus of Victoria Blue, BOC, as sold by Du Pont, or Victoria Blue base, as sold by Du Pont. There may also be used Crystal Violet, as sold by National Aniline Company. To provide a dark red color there may be suitably used Rhodamine B-base as sold by Du Pont.

I may provide "a plurality of colors so that various colors may be used for various purposes by ultimate users to indicate, for example, the type of materials which have been copied or locations in which more copies would be filed, or other information.

In order to improve the adhesion of the thermoplastic coating to the backing sheet, there may be added to the formulation thereof from 1-3% of a relatively tacky material such as alkyd resins or modified resin ester or I'OSIH.

A preferred synthetic organic resinous backing sheet may be either opaque or translucent or transparent to visual rays and infrared rays, has a surface capable of providing good adhesion to coatings and is devoid of irregularities in thickness. The thickness of the backing sheet depends on the thermoplastic material used and its transparency to heat as well as other factors.

The backing sheet may be any fibrous or regenerated cellulose or any continuous film. Materials which are suitable include: cellulose esters such as cellulose acetate and cellulose butyrate, cellulose t-riacetate, styrene and its derivatives, vinyl polymers such as vinyl chloride, vinylidine chloride or copolymers thereof, polyvinyl acetate such as polyvinyl butyral, vinyl acetate, polyvinyl alcohol,

'3' Mylar (a polyester film produced by the Du Pont Company), Tygonta series of compounded, modified, halide polymers, condensation resins and diene derivatives produced by US. Stoneware), nylon or any other film-former which is relatively transparent to heat.

A preferred fibrous material for a backing sheet is an opaque material which is partially transparent to heat, has a rough surface to provide good adhesion to coatings and has excellent uniformity of fiber structure and is devoid of fiber and filler irregularities which tend to cause graininess in an image. Suitable papers include a .019", 13 lb. (per 500 sheets of 20 x 30 inch size) milo paper produced by S. D. Warren Company, Portland, Maine; a .020", 15 lb. (per 500 sheets of x 20 inch size) white milo paper produced by the same company; and a .015", lb. (per 500 sheets of 24 x 36 inch size) white greaseproof paper made by the Riegel Paper Company.

TEE backing sheet when opaque furnishes a negative copy and copies may be made therefrom according to my method, however if the backing sheet is translucent or transparent the copy may be read from the back.

The indicia-bearing sheets which are applicable for copying in accordance with my method include opaque, transparent and translucent sheets having indica thereon. Materials such as photographic prints and stencils carrying visually unobservable indicia or apertured indicia are not suitable for copying.

The preferred method for making copies of indicia is juxtaposing a sheet having indicia thereon with either a plasticized thermoplastic synthetic resin or a thermoplastic synthetic resin coating on a backing sheet, said resin having a non-tacky surface at temperatures below 100 F. and having a softening point from 150 F. to 350 F. followed by exposing the resultant body to heat to form a copy of the indicia.

Another method comprises a dark colored copying sheet juxtaposed with a sheet having indicia thereon, followed by exposure to a temperature between 150 F. to 350 F. This activated colored copying sheet, while it is unreadable, may be used as a negative for additional reproductions. The activated copying sheets may have serial numbers placed thereon, so that a chronological file could be set up to hold the negatives, this being suitable where a complete chronological file of all correspondence is desired.

The invention is further illustrated by the following examples which illustrate certain embodiments but are not to be taken as limiting the invention only to those particular embodiments illustrated, it being understood that other embodiments and equivalents will be apparent to those skilled in the art.

Example 1 A coating having the following formulation:

1 part by weight polyvinyl chloride resin (prepared by Borden) 4 parts by \veightmethyl ethyl ketone .1 part by weight Unidol 40 .4 part by weight Pliolite 8-5 (a viscosity improver for coatings, a thermoplastic copolymer produced by Goodyear) is mixed and coated on a cellulose tr-iacetate sheet .002" thick using a Mayer equalizer rod to provide a coating layer having a thickness of about .004, then dried. Copying sheets are then cut out. One of the copying sheets utilizable in my method is then laid against printed sheets and exposed for about 20 seconds at 180 F. This heat causes the coating to become 'tacky and the coating then picks .up particles from the indicia of the printed sheet. Excellent copies of the original are obtained.

Example 2 A coating having the following formulation:

1 part by weight Vinac B75 (a polyvinyl acetate produced by the Colton Chemical Company.)

1 part Parlon, 20 cps.

23 parts by weight acetone 23 parts by weight of toluene Example 3 A sheet of cellulose acetate .015" thick is rod coated with RX70 Blue adhesive (a rubber base adhesive produced by Industrial Latex Company) to a 3 mil wet thickness coating over the cellulose acetate sheet. The RX70 Blue adhesive is then coated with a 1-2 mil thickness coating of Vinac B15 (a polyvinyl acetate produced by the Colton Chemical Company). The resulting sheet is then juxtaposed with an indicia bearing sheet and the resultant assembly exposed to heat to soften the coating until it becomes tacky and picks up particles from the indicia to give a blue copying sheet having a copy of the indicia of the indicia bearing sheet thereon,

Example 4 A coating having the following formulation:

is mixed and coated on a cellulose triacetate sheet .01" thick with a transfer roll and Mayer equalizer rod dried and stored one week. The resultant sheet is then laid against a typewritten sheet and exposed for 5 seconds at 170 F. to provide a copy of the typewritten sheet.

Example 5 A coating having the following formulation:

2.1 grams Vinac B7 in a 57% solution of acetone (Vinac B-7, a low viscosity and low molecular weight poly vinyl acetate produced by the Colton Chemical Com- P m) 3.2 grams of Parlon, 20 cps., in a 58% solution toluol (Parlon, Q0 cps., a chlorinated rubber produced by Hercules Chemical Company) 2.0 grams tricresyl phosphate is brushed on a 3 mil cellulose triacetate sheet and air dried. The coated copying sheet thus obtained is laid against a typewritten sheet having pencil notations thereon, exposed for 10 seconds at 205 F. The heat softens the coating until it becomes tacky and picks up particles from the type and the pencil notations to produce a copy of the sheet which is to be copied.

Example 6 A polyvinyl alcohol film sheet 3 mils thick is laid against a typewritten sheet and exposed for 20 seconds at F. The heat causes the film to soften until it becomes tacky and picks up a portion of the indicia particles from the original to provide a copying sheet having clear indicia contrasting to the color :of the copying sheet. The activated copying sheet may'then be laminated to a partially heat transparent backing sheet to provide a permanent copy of said aetivatedcopy sheet.

Example-7 j The composition of Example is coated on a web of 16 pound white milo paper as hereinbefore described to provide a coating .003" thick when wet and is then dried. The copying sheet thus obtained is then juxtaposed with an indicia bearing sheet and the. resultant assembly exposed to heat to provide a copy of the indicia.

Example 8 The composition of Example 1 is coated on 16 pound white milo paper as hereinbefore described to provide a coating .5 thick. The coating on the copying sheet is then dried. The copying sheet thus obtained is juxtaposed with the indicia of an indicia bearing sheet and exposed to heat to provide a copy of the indicia on the copying sheet. This copying sheet can be utilized for additional reproductions if the original has to be returned and additional copies are needed.

Example 9 The composition of Example 4 is coated on a 4 colored regenerated cellulose film sheet to give acoating .015" thick and after air drying the resultant sheet is laid against a typewritten sheet to be copied and exposed for 15 seconds at 180 F. to provide a copy of the typewritten indicia.

Example 10 The activated copying sheet of Example 4 is laid against a heat-sensitive copying paper as disclosed in U.S. Patent 2,663,655. The resultant body is exposed to radiant energy and a copy of a copy is thereby provided.

Example 11 up particles from the indicia of the letter to provide an excellent copy of the original.

Example 12 The coating composition of Example 5 is applied to a polyvinyl alcohol film sheet until the coating is .004" thick and then is allowed to air dry. The resultant coated sheet is cut to provide a copying sheet. One of the aforementioned copying sheets is laid against a typewritten letter, said letter being typed on stationery having green letterhead and the resultant assembly 15 then exposed to a temperature of 200 F. for 12 seconds. The coating composition softened and picked up the particles from the indicia on the stationery to provide a copy of not only the typewritten indicia but also the green letterhead.

Example 13 The coating composition of Example 1 is applied to a Mylar film sheet to provide a coating .0025 thick and then air dried. The resultant coated sheet is cut to provide copying sheets. One of the aforementioned copying sheets is laid against a mimeographed page having notations in blue ink thereon and then exposed to a temperature of 195 F. for 15 seconds. The coating composition softened, suficiently to become tacky and picked up the particles from the indicia on the mimeographed page juxtaposed'therewith and'also picked up blue 0136 ticles from the-notations written in blue ink'thereomto provide a duplicate copy of the original. This activated copying sheet is then juxtaposed with a thermal copying sheet as is described in U.S. Patent 2,663,654 and exposed to radiant energy to produce a copy of the heat-absorbent indicia of the original.

r 0 Example 14 The activated copying sheet of Example 5 is placed against a heat sensitive copying paper of the type de-' scribed in my copending application Serial No. 644,541 and is exposed to radiant energy to provide an exact duplicate to the original described in Example 5.

Example 15 The activated copying sheet of Example 8 is placed against a heat sensitive copying paper as disclosed in U.S. Patent 2,663,654 and is exposed to a temperature of 250 F. for 5 seconds to provide an excellent copy of the original indicia.

Example 16 The activated copy sheet of Example 11 is placed against a heat sensitive copying paper of the type described in U.S. Patent 2,668,126 and is exposed to radiant energy to provide a duplicate of heat absorbent indicia described in Example 11.

Example 17 Example 18 A polyvinyl alcohol film sheet 1 mil thick is laminated to a partially heat transparent backing sheet of 16 pound white milo paper as hereinbefore described and the resultant laminate laid against the type of a typewritten sheet and exposed for 20 seconds at F. The heat causes the film to soften until it becomes tacky and picks up a portion of the type from the type of original typewritten sheet to provide a permanent copying sheet having indicia contrasted to the color of the backing sheet.

Particular advantages of the method of my invention are (1) colors may be reproduced from originals, (2) both heat sources and radiant energy may be employed for activation, (3) good contrast of indicia to background may be obtained, (4) short exposure periods may be used to produce excellent copies, and (5) the copy sheet utilized, after activation, may be used with known thermal copying sheets to produce additional copies; the latter being especially advantageous when the original has been returned and additional copies are required.

It should also be noted that the method of. my invention is capable of reproducing signatures, of which methods heretofore have not been capable. This fact is especially noteworthy since it has not been possible to make exact reproductions of complete letters, even including signatures.

It may thus be seen that the invention is broad in scope and includes such modifications as will be apparent to those skilled in the art and is to be limited only by the claim.

Having thus described my invention, I claim:

A method for copying relatively non infra-red absorptive indicia comprising providing an indicia bearing sheet wherein indicia on said sheet are substantially as non infra-red absorptive as such sheet and juxtaposing incontact with said indicia a second sheet comprising a film of flexible fold-able synthetic organic resin, subjecting the thus provided assembly of two sheets to infrared radiation so that at least aportion ofsaid radiation is absorbed by at least one of said sheets to soften said second sheet and cause atleast a portionof-said indicia to adhere to said second sheet and then causing said assembly to cool until said second sheet has lost said softening and then separating said sheets to complete the transfer of a portion of said indicia fromsaid first sheet to said "References-Cited in the file of this patent UNITED STATES PATENTS 2,501, 9 Car o et Mar- 21 5 2,715,363 Hoover Aug. 16 1955 2,721,821 Hoover Oct. 25, 1955 2,740,896 Miller Apr. 3, 1956 2,808,777 Roshkind Oct. ,8, 1957