CA1192046A - Electrosensitive transfer film - Google Patents
Electrosensitive transfer filmInfo
- Publication number
- CA1192046A CA1192046A CA000431885A CA431885A CA1192046A CA 1192046 A CA1192046 A CA 1192046A CA 000431885 A CA000431885 A CA 000431885A CA 431885 A CA431885 A CA 431885A CA 1192046 A CA1192046 A CA 1192046A
- Authority
- CA
- Canada
- Prior art keywords
- resin
- layer
- electric discharge
- resin layer
- particles
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
- B41M5/00—Duplicating or marking methods; Sheet materials for use therein
- B41M5/26—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used
- B41M5/382—Contact thermal transfer or sublimation processes
- B41M5/3825—Electric current carrying heat transfer sheets
Abstract
ABSTRACT OF THE DISCLOSURE
An electric discharge transfer film material comprising at least two layers, the first of which is (a) an electrically anisotropic support layer (2) having electroconductive particles dispersed in a resin matrix.
The electroconductive particles can be graphite par-ticles having a particle size between 0.1 to 20 microns, carbon black particles having a particle size between 25 to 500 millimicrons, or metal powders, and (b) at least one thermal or electrothermal transfer layer (4) in the form of a resin layer capable of being broken by elec-trical discharge and transferred to a record sheet, e.g., paper.
An electric discharge transfer film material comprising at least two layers, the first of which is (a) an electrically anisotropic support layer (2) having electroconductive particles dispersed in a resin matrix.
The electroconductive particles can be graphite par-ticles having a particle size between 0.1 to 20 microns, carbon black particles having a particle size between 25 to 500 millimicrons, or metal powders, and (b) at least one thermal or electrothermal transfer layer (4) in the form of a resin layer capable of being broken by elec-trical discharge and transferred to a record sheet, e.g., paper.
Description
BACKGROUND OF THE INVENTION
2 1. Fie1d of the Invention
3 The present invention relates to a composite
4 electrosensitive transfer material, and more particu-larly, to a reusable electrosensitive transfer film.
6 2. Description of the Prior Art 7 In recent years, various systems have been 8 proposed for the rapid transmission and/or recording of g information. One such system is an electric discharge recording system.
11 The electric discharge recording system is a 12 process which comprises applying an electrical signal OL
13 several hundred volts and several watts in the form of 14 an electric voltage, and breaking a semiconductive recording layer on the surface of a recording layer by 16 electric discharge, thereby to form an image on the 17 recording layer or on a substrate superimposed on the 18 recording layer. This process is a "direct imaging"
19 process which does not require processing operations such as development and fixation, and is in widespread 21 use as a simple recording process. For example, the 22 process finds applications in facsimile systems, various 23 measuring instruments, recording meters, record displays 24 in computers, and processing of electrostencil master sheets 26 In the electric discharge recording, a dis-27 charge recording stylus is directly contacted with the 28 recording surface of an electric discharge recording 29 material. Discharging is performed through the stylus to break the recording layer, and to form an image on 31 the recording surface.
~, 1 A more recent development is disclosed by 2 Nakano et al in U.S. Patent 4,163,075 and relates to the 3 use of an electrosensitive transfer film. To record 4 with this type of film it is laid over an untreated sheet of a receiving medium, such as paper, and an 6 electric discharge stylus is moved in a regular pattern 7 across the back of the transfer film. Provision is 8 generally made to ground either one edge or the front g surface of the transfer film. When a voltage on the order of 150 to 200 volts is applied to the stylus, 11 current flows through the sheet and matter is caused to 12 be transferred to the receiving sheet, e.g., paper.
13 The film disclosed by Nakano et al in U.S.
14 Patent 4,163,075, comprises three layers, namely a film support layer and two transfer layers. The support 16 layer is composed of a metal powder-containing resin 17 layer, eOg., electrolytic copper powder having an 18 average diameter of 2 microns dispersed in a vinyl 19 chloride resin.
Numerous disadvantages appear to exist with 21 the use of the products disclosed in the Nakano et al 22 patent. For example, the use of small metal particles 23 in the support layer results in a high cost product 24 affecting the commercial success of the product. A
need therefore exists for a transfer sheet exhibiting 26 improved image quality that can be produced at a low 27 cost compared to other commercially available products~
29 It is an object of this invention to provide an electric discharge transfer film which is free from 31 the disadvantages described hereinabove.
1 According to the present invention, an elec-2 tric discharge recording material is provided which 3 comprises (a) an electrically anisotropic support 4 layer having electroconductive particles dispersed in a resin matrix wherein said electroconductive particles 6 are: (1) graphite particles having a particle size 7 between 0.1 to 20 microns, (2) carbon black particles 8 having a particle size between 25 to 500 millimicrons, g or (3) metal powders; and (b) at least one thermal or electrothermal transfer layer in the form of a resin 11 layer capable of being broken by electrical discharge 12 and transferred to a record sheet. A preferred resin 13 matrix comprises a phenoxy resin of the formula:
O = C ~ ~ O-C-C C
17 _ _ n 18 where n is about 100.
19 One embodiment of the present invention is an electric discharge recording material which comprises:
21 (a) a semiconductive resin layer capable of being 22 broken by electric discharging which has a surface 23 resistance of 105 to 1016 ohms and a volume resistance 24 of 103 to 1014 ohms-cm; (b) an electroconductive elec-trically anisotropic resin layer containing electro-26 conductive particles such as graphite, carbon black or 27 metal powders as described above, which is laminated on 28 one surface of the semiconductive resin layer (a); and 29 a conductive layer having a surface resistance of not more than 104 ohms and a volume resistance of not more 31 than 102 ohms-cm, which is laminated on the other 32 surface of the semiconductive resin layer (a).
1 Another embodiment of the present invention is 2 an electric discharge recording material which comprises 3 at least one resin layer capable of being thermally or 4 electrothermally transferable to another substrate, and an electrically anisotropic carbon black or graphite-h containing resin layer which is laminated on one surface 7 of one resin layer.
8 Still another embodiment of the present g invention is an electric discharge recording material, e.g., film, which comprises at least one resin layer 11 capable of being thermally or electrothermally trans-12 ferred to another substrate and an electrically aniso-13 tropic carbon black or graphite-containing support 14 layer. The graphite and carbon black particles exhibit particle sizes previously defined herein. The support 16 layer is laminated onto one surface of the resin layerO
17 Other objects, features and effects of this 18 invention will become more apparent from the following 19 detailed description considered with the drawings wherein:
21 Figure 1 is an expanded sectional view of the 22 transfer film of this invention.
24 The film structure, as illustrated in FIGURE
1, comprises an electrically anisotropic (unidirection-26 ally conductive) electroconductive particle-support 27 layer 2 and two transfer layers, namely layers 4 and 6.
28 When a graphite-containing resin is employed 29 as layer 2, it generally contains between 5 to 65% and preferably between 15 to 45% by weight graphite based 1 on the weight of the resin. Best results are obtained 2 when the layer contains between 25 and 35~ by weight 3 graphite, based on the weight of the resin. The par-4 ticle diameter of the graphite used in this layer is also critical to the successful practice of the ~ subject invention. Generally, the particle size is 7 generally between 0.1 to 20 microns, and preferably 8 between 0.1-5 microns, with best results being achieved g with particles between 0.1 and 1 microns.
According to an embodiment of this invention, 11 graphite particles useful in the anisotropic support 12 layer can be prepared by grinding the graphite particles 13 in the presence of water or other solvent having sub-14 stantially the same freezing and vapor pressure proper-ties as water, e.g., tertiary butyl alcohol, cyclohexane, 16 benzene, dioxane, and para-xylene. Generally~ between 17 about 70 and 80% by weight of the slurry is water or 18 solvent, as defined herein, the balance being solids, 19 namely the graphite particles. It is understood that the amount of water or solvent employed is not 21 critical and can vary over wide ranges both below 70%
22 and above 80% because the solvent or water is eventually 23 driven off in accordance with this process. Grinding 2~ takes place for a period of time sufficient to achieve substantially complete dispersion of the graphite 26 particles in the solvent or water. Generally, such 27 grinding takes place between 8 and 16 hours to achieve 28 the substantial dispersion of the graphite particles.
29 The term "substantial", as used in this context, means at least 95% of the graphite being dispersed in the 31 water or solvent with as little as possible agglomeri-32 zation of the graphite being present. Grinding is 33 generally accomplished by subjecting the slurry to a 34 ball mill, sand mill or any other clispersion technique well~known to those of ordinary skill in the art. It is particularly preferred -to reduce agglomera-tes of graphite and to obtain substantial dispersion of the graphite particles with an "ATTRITOR" , Model 01, made by Union Process Company, Dayton, Ohio.
A binding polymer is added to the graphite slurry, either during the grinding step or immediately after the grinding step for the purpose of forming a film or coating on the individual particles of graphite.
The polymer employed is to be soluble in the water or solvent of the slurry. Suitable polymers include, e.g., polyvinyl alcohol, gelatin or methyl cellulose.
Freezing of the slurry is achieved by lower-ing the temperature to a point wherein the physical state of the solvent changes from liquid to solid.
The frozen slurry is then dried, under conditions such that the water solvent present is caused to sublime, i.e., the solid is directly converted to the vapor form, without passage through the liquid state. The process results in the formation of a sub-stantial amount of undamaged polymeric coated graphite particles having a diameter of at least 0.2 microns.
By substantial amount, it is intended that a-t least 90% of the particles have a diameter of at least 0.2 microns.
Sublimation of water, or other solvents used in place of wa-ter, which exists in the solid s-tate, can be caused to change to a gaseous phase without an intermediate phase, under well-known changes in pres-sure alone, tempera-ture alone, or a change in both temperature and pressure. Generally, sublimation can be produced under the influence of a high-pressure vacuum.
It is critical that the graphite particles be dispersed in the resin in such a manner the graphi-te is ~D~Z~
not reduced in size to dust particles (under 0.1 micron).
Graphite particles are therefore dispersed in a resin, generally in a mol-ten state, by means of a high sheer blender, e.g., a Waring blender, Cowl or Greer blenders, rather than by impact grinding methods, e.g., ball milling or dispersing in an attritor. The latter methods cause the graphite particles to greak up into particles less than 0.1 micron size, adversely affect-ing the electrically anisotropic properties of the layer.
When the electroconductive particles are carbon black particles, the electrically conductive carbon-black-containing resin of layer 2 contains generally between 60 to 70% by weight carbon black.
Best results are obtained when the layer contains 65%
by weight carbon black, based on the weight of the resin and carbon black. The particle diameter of the carbon black used in this layer is also eritieal to the successful practice of the subject invention. Gener-ally, the partiele size is generally between 25 and500 millimierons, with best results being aehieved with partieles of about 350 millimierons.
Carbon blaek is available from numerous commercial sources. For the present invention, channel blacks, ~urnace blacks, and thermal blacks are useful in the practice of the invention. Examples of suit-able earbon blaeks inelude those sold under the mark T~RMAXTM
The resin whieh eonstitutes the resin matrix in whieh the elec-troeonduetive partieles of the aniso-tropie layer are dispersed may be any thermoplastic or thermosetting resin whieh has film-forming ability and eleetrieal insulation (generally having a volume resis-tanee of at least 107 ohms-em). Generally, the matrix resin preferably has a great ability to bind the elec-tro-conductive particle and can be formed into sheets or films having high mechanical strength, flexibility and high stiffness.
A preferred resin that is useful in the resin matrix, in which the electro-conductive particles are dispersed, is a phenoxy resin of the formula:
{ O \ ~ C ~ O-C-C-C n wherein n is about 100.
A suitable phenoxy resin is sold by Union Carbide Corporation under the trademark "PKH~I"
This resin has the following characteristics:
Approximate Molecular Weight 20,000 to 30,000 Specific Gravity 1.18 Melt Flow (g/10 minutes at 220C) 2.5-10 Ultimate Tensile Strength, psi 9,000-9,500 Ultimate Tensile Elongation 50-100 Softening Temperature 100C
Moisture Vapor Transmission 3.5 gms/mil/
24 hrs/100 in.
Molecular Structure As shown above Generally, the matrix resin preferably has a great ability to bind the elec-troconductive particles, e.g., graphite, carbon black or the metal powders disclosed in U. S. Patent ~,163,075 or other useful electroconductive particles that may be used. These resins can be formed into sheets or films having high mechanical strength, flexibility and high stiffnessO
1 Examples oE suitable resins that can be used 2 in this invention are thermoplastic resins such as 3 polyolefins (such as polyethylene or polypropylene), 4 polyvinyl chloride, polyvinyl acetal, cellulose acetate, polyvinyl chloride, polyvinyl acetal, cellulose acetate, 6 polyvinyl acetate, polystyrene, polymethyl acrylate, 7 polymethyl methacrylate, polyacrylonitrile, thermo-8 plastic polyesters, polyvinyl alcohol, and gelatin; and g thermosetting resins such as thermosetting polyesters, epoxy resins, and melamine resins. The thermoplastic 11 resins are preferred, and polyethylene, polyvinyl 12 acetal, cellulose acetate, and thermoplastic polyesters 13 are especially preferred.
1~ As is conventional in the art, additives such as plasticizers, fillers, lubricants, stabilizers, 16 antioxidants or mold releasing agents may be added as 17 needed to the resin in order to improve its moldability, 18 storage stability, plasticity, tackiness, lubricity, 19 etc.
Examples of the plasticizers are dioctyl 21 phthalate, dibutyl phthalate, dicapryl phthalate, 22 dioctyl adipate, diisobutyl adipate, triethylene glycol 23 di(2-ethyl butyrate), dibutyl sebacate, dioctyl azelate, 2~ and triethylhexyl phosphate, which are generally used as plasticiæers for resins. The amount of the plasticizer 26 can be varied over a wide range according, for example, 27 to the type of the resin and the type of the plasticizer 28 Generally, its amount is at most 150 parts by weight, 29 preferably up to 100 parts by weight, per 100 parts by weight of the resin. The optimum amount of the 31 plasticizer is not more than 80 parts by weight per 100 32 parts by weight of ~he resin.
1 Examples of fillers are fine powders of 2 calcium oxide, magnesium oxide, sodium carbonate, 3 potassium carbonate, strontium carbonate, zinc oxide, 4 titanium oxide, barium sulfate, lithopone, basic mag-nesium carbonate, calcium carbonate, silica, and kaolin.
6 They may be used either alone or as mixtures of two or 7 more.
8 The amount of the filler is not critical, and 9 can be varied over a wide range according to the type of the resin, the type of the filler, etc. Generally, the 11 amount is up to 1000 parts by weight, preferably not 12 more than 500 parts by weight, more preferably up to 200 13 parts by weight.
14 Usually its thickness is at least 3 microns.
The upper limit of the thickness is not strict, but is 16 advantageously set at 100 microns for the reason stated 17 above. Preferably, the thickness is 5 to 60 microns, 18 more preferably 10 to 40 microns.
19 The semiconductive resin layer 4 laminated on the electroconductive particle-containing resin layer is 21 broken by discharging. It has a surface resistance of 22 10 to 109 ohms, preferably 103 to 107 ohms, more prefer-23 ably 104 to 1o6 ohms and a volume resistance of 11 to 24 106 ohms-cm, preferably 11 to 105 ohms-cm, more prefer-ably 102 to 104 ohms-cm.
26 The semiconductive resin layer ~ can be formed 27 by dispersing a conductivity-imparting agent in a resin 28 matrix.
29 The resin matrix forming a substrate for the semiconductive resin layer 4 may be chosen from those 31 which have been described hereinabove about the non-1 recording layer composed of an electroconductive par-2 ticle-containing resin. The thermoplastic resins are 3 especially suitable, and polyethylene, cellulose acetate 4 and polyvinyl acetal are used advantageously~ As needed, the resin may contain additives of the types 6 described hereinabove such as plasticizers and fillers 7 in the amounts described.
8 When a filler having a different conductivity g from the conductivity-imparting agent, generally having a lower conductivity than the conductivity-imparting 11 agent, is included in the semiconductive resin layer 4, 12 the breakdown of the semiconductive resin layer 4 by 13 electric discharging occurs more sharply, and a recorded ]4 image which is clearer and has a higher contrast can be obtained. Suitable fillers of this kind are fine 16 powders of inorganic substances such as magnesium oxide, 17 calcium oxide, sodium carbonate, potassium carbonate, 18 strontium carbonate, titanium oxide, barium sulfate, 19 lithopone, basic magnesium carbonate, calcium carbonate, silica, kaolin clay, and zinc oxide. They can be used 21 singly or as a mixture of two or more. Of these, 22 titanium oxide and calcium carbonate are especially 23 suitable. The average particle diameter of the filler 24 is generally 10 microns at most, preferably not more than 5 microns, more preferably 2 to 0.1 microns. The 26 amount of the filler can be varied over a wide range 27 according to the type of the resin, etc. The suitable 28 amount is generally 10 to 2,000 parts by weight, prefer-29 ably 20 to 1,000 parts by weight, more preferably 50 to 400 parts by weight, per 100 parts by weight of the 31 resin.
32 The conductivity-imparting agent to be dis-33 persed in the resin to impart semiconductivity may be 34 any material which has conductivity and gives the 1 surface resistance and volume resistance described above 2 to the resin layer. Generally, suitable conductivity-3 imparting agents have a specific resistance, measured 4 under a pressure of 50 kg/cm2, of not more than 106 ohms-cm. Examples of such a conductivity-imparting 6 agent include carbon blacks; metals such as gold, 7 silver, nickel, molybdenum, copper, aluminum, iron 8 and conductive zinc oxide (zinc oxide doped with 0.03 g to 2.0% by weight, preferably 0.05 to 1.0% by weight, based on the zinc oxide, of a different metal such as 11 aluminum, gallium, germanium, indium, tin, antimony or 12 iron); conductive metal-containing compounds such as 13 cuprous iodide, stannic oxide, and metastannic acid; and 14 zeolites. Of these, carbon blacks, silver, nickel, suprous iodide, conductive zinc oxide are preferred, 16 and carbon blacks and conductive zinc oxide are more 17 preferred. The carbon blacks which also act as a 18 coloring agent are most preferred.
19 Carbon blacks differ somewhat in conductivity according to the method of productionO Generally, 21 acetylene black, furnace black, channel black, and 22 thermal black can be used.
23 The conductivity-imparting agent is dispersed 24 usually in the form of a fine powder in the resin. The average particle diameter of the conductivty-imparting 26 agent is 10 microns at most, preferably not more than 5 27 microns, especially preferably 2 to 0.005 microns. When 28 a metal powder is used as the conductivity-imparting 29 agent, it is preferably in a microspherical, dendric or microlumpy form. Moreover, since a resin sheet 31 having the metal powder dispersed therein tends to be 32 electrically anisotropic if its particle diameter 33 exceeds 0.2 micron. ~lence, the particle size of a metal 34 powder in the above-mentioned form to be used as a 1 conductivity-imparting agent for the semiconductive 2 resin layer 4 or the conductive layer 6 should be at 3 most 0.5 micron, preferably not more than 0.2 micron, 4 more preferably 0.15 to 0.04 micron. Scale-like or needle-like powders can also be used, but should be 6 combined with powders of the above forms.
7 The amount of the conductivity-imparting agent 8 to be added to the resin can be varied over a very wide g range according to the conductivity of the conductivity-imparting agent, etc. The amount is that sufficient 11 to adjust the surface resistance and volume resistance 12 f the semiconductive resin layer 4 to the above-13 mentioned ranges. For example, carbon blacks are 14 incorporated generally in an amount of 1 to 300 parts by weight, preferably 2 to 200 parts by weight, more 16 preferably 3 to 150 parts by weight, per 100 parts by 17 weight of the resin. The other conductivity-imparting 18 agents are used generally in an amount of 3 to 500 parts 19 by weight, preferably 5 to 400 parts by weight, more preferably 10 to 300 parts by weight, per 100 parts by 21 weight of the resin.
22 The thickness of the semiconductive resin 23 layer 4 is not critical, and can be varied over a wide 24 range according to the uses of the final product, etc. Generally, its thickness is at least 2 microns, 26 preferably 3 to 50 microns, more preferably 5 to 20 27 micronS.
28 According to the present invention, the 29 conductive layer 6 is laminated on the other surface of the semiconductive resin layer 4.
31 The conductive layer 6 plays an important role 32 in performing electric discharge breakdown with high 1 accuracy by converging the current flowing through the 2 semiconductive resin layer at a point immediately 3 downward of the electric discharge recording stylus.
~ The conductive layer 6 has a surface resistance of not more than 104 ohms, preferably not more than 5 x 103 6 ohms, more preferably 10~1 to 2 x 103 ohms and a volume 7 resistance of not more than 102 ohms-cm, preferably not 8 more than 50 ohms-cm, more preferably not more than 20 g ohms-cm.
The conductive layer 6 having such resistance 11 characteristics may be a conductive resin layer com-12 prising a thermoplastic or thermosetting resin and a 13 conductivity-imparting agent dispersed in it, a vacuum-14 deposited metal layer, or a metal foil layer.
The thermoplastic or thermosetting resin that 16 can be used in the conductive resin layer can also be 17 selected from those described hereinabove in connection 18 with the non-recording layer. Of these, the thermo-19 plastic resins, especially polyethylene, cellulose acetate and polyvinyl acetal, are used advantageously.
21 The conductivity-imparting agent to be dispersed in the 22 resin may be chosen from those described above in 23 connection with the semiconductive resin layer. Carbon 24 blacks and metal powders are especially suitable~
Carbon blacks are particularly preferred over metals in 26 view of cost factors.
27 The conductivity-imparting agents are added in 28 amounts which will cause the resin layer to have the 29 electrical resistance characteristics described above.
The amounts vary greatly according to the type of the 31 conductivity-imparting agent. For example, carbon 32 blacks are used in an amount of generally at least 10 33 parts by weight, preferably 20 to 200 parts by weight, 1 more preferably 30 to 100 parts by weight; the other 2 conductivity-imparting agents especially metal powders, 3 are used in an amount of at least 50 parts by weight, 4 preferably 100 to 600 parts by weight, more preferably 150 to 400 parts by weight, both per 100 parts by weight 6 of the resin.
7 As needed, the conductive resin layer may 8 contain the aforesaid additives such as plasticiæers and g fillers in the amounts stated.
The thickness of the conductive resin layer is 11 not critical, and can be varied widely according to the 12 uses of the final products, etc. Generally, it is at 13 least 3 microns, preferably 3 to 50 microns, more 14 preferably 5 to 20 microns.
The conductive layer 6 may be a vacuum 16 deposited metal layer. Specific examples of the metal 17 are aluminum, zinc, copper, silver and goldO Of these, 18 aluminum is most suitable.
19 The thickness of the vacuum-deposited metal layer is not critical. Generally, it is at least 4 21 millimicrons, preferably 10 to 300 millimicrons, 22 more preferably 20 to 100 millimicrons. By an ordinary 23 vacuum-depositing method for metal, it can be applied to 24 one surface of the semiconductive resin layer 4.
The conductive layer 6 may also be a thin 26 metal foil, for example, an aluminum foil. It can be 27 applied to one surface of the semiconductive resin layer 28 4 by such means as bonding or plating.
29 It is understood that at least one of the layers 4 and 6 may contain a coloring substance. Useful 1 coloring substances are carbon black, inorganic and 2 organic pigments, and dyes.
3 Carbon black has superior conductivity and 4 acts both as a coloring substance and a conductivity-imparting agent as stated above. Thus, when the semi-6 conductive resin layer or the conductive resin layer 7 already contains carbon ~lack as a conductivity-impart-8 ing agent, it is not necessary to add a further coloring 9 substance. The inclusion of other suitable coloring substance is of course permissible.
11 Examples of pigments other than carbon black 12 include inorganic pigments such as nickel yellow, 13 titanium yellow, cadmium yellow, zinc yellow, ochre, 14 cadmium red, prussian blue, ultramarine blue, zinc white, lead sulfate, lithopone, titanium oxide, black 16 iron oxide, chrome orange, chrome vermilion, red iron 17 oxide, red lead and vermilion, and organic pigments of 18 the phthalocyanine, quinacridone and benzidine series 19 such as aniline black, naphthol yellow S, hanza yellow 10G, benzidine yellow, permanent yellow, Permanent 21 Orange, Benzidine Orange G, Indanthrene Brilliant Orange 22 GK, Permanent Red 4R, Brilliant Fast Scarlet, Permanent 23 Red F2R, Lake Red C, Cinquasia Red Y (Dup) (C. I. 46500), 24 Permanent Pink E (F~l) [Quido Magenta RV 6803(~AR)], and Phthalocyanine Blue (C.I. Pigment Blue 15).
Examples of useful dyes are azoic dyes, 27 anthraquinonic dyes, thionidigo dyes, quinoline dyes, 28 and indanthrene dyes.
29 The pigments and dyes described are used either alone or in combination according to the color 31 desired to be formed on a transfer recording sheet.
1 The amount of the pigment or dye can be varied 2 over a wide range according to the type, color intensity, 3 etc. of the coloring substanceO Generally, it is at 4 least 1 part by weight, preferably 2 to 1,000 parts by weight, more preferably 3 to 500 parts by weight, per 6 100 parts by weight of the resin.
7 When the pigment or dye is to be incorporated 8 in both of the semiconductive resin layer 4 and the g conductive resin layer 6, it is desirable that pigments or dyes be of an identical color or have colors of the 11 same series.
12 The composite electric discharge recording 13 material of this invention can be formed by known 14 methods, for example a melt-extrusion method, a melt-coating method, a melt-calendering method, a solution 16 casting method, an emulsion casting method or combi-17 nations of these methods.
18 The composite electric discharge recording 19 material of this invention described above is useful as an electric discharge transfer recording material or an 21 electric stencil master sheet.
22 The electric discharge transfer recording 23 mediums of the present invention are generally employed 24 by superimposing the transfer recording medium onto a recording sheet 8, e.g., cellulosic paper, a synthetic 26 paper-like sheet or a plastic sheet so that the conduc-27 tive layer 6 contacts recording sheet 8. When electric 28 discharge recording is performed by a discharge record-29 ing stylus in accordance with an ordinary method from the side of the electroconductive powder-containing 31 resin layer 2, the semiconductive resin layer 4 and the 32 conductive layer 6 are simultaneously broken by electric .~f~
1 discharging, and the broken pieces 10 are transferred to 2 the record sheet and fixed thereon, thereby achieving 3 transfer recording.
9 According to a further embodiment of the present invention, a color coupler may be put in one or 6 more transfer layers to react with a material in the 7 recording material or paper, to generate a colored 8 image, e.g., bisphenol A and leuco dye.
g It is understood that the electric discharge transfer film of this invention can be processed to any 11 desired width or length in accordance with its desired 12 use. For example, the transfer film can be used in the 13 form of a narrow tape, such as a typewriter ribbon.
14 In electric discharge recording, the semi-conductive resin layer and the conductive layer of the 16 composite electric discharge transfer recording material 17 are broken down, but the electroconductive powder-18 containing resin layer is not broken because of its 19 electric anisotropy and remains substantially unchanged.
Accordingly, dissipation of any offensive odor issued 21 at the time of electric discharge breakdown is inhibited, 22 and soot or a coloring substance such as carbon black is 23 prevented from scattering and adhering to the discharge 24 recording stylus. The troublesome inspection and maintenance of the discharge recording stylus can be 26 markedly reduced, and recording can be performed with 27 high reliability. The term "electrical anisotropy"
28 refers to the low resistance of support layer or 29 electroconductive particle containing resin layer 2 in the through direction and the high resistance of this 31 layer in the lateral direction.
1 The use of the composite electric discharge 2 recording material can afford a sharp recorded image, 3 and in electric discharge transfer recording, a transfer 4 recorded image having a high density, a natural appear-ance and a soft tone can be obtained.
6 The composite electric discharge recording 7 material of this invention can be used a plurality of 8 times.
9 The composite electric discharge recording material of this invention can be conveniently used 11 in facsimile systems, terminal recording devices in 12 electronic computers, automatic recording devices of 13 automatic measuring instruments, and various types of 14 printers, etc.
In the present specification, the terms 16 "surface resistance" and "volume resistance" is deter-17 mined in accordance with the method described by H. R.
18 Dalton in U.S. Patent 2,664,044.
19 In the detailed description of the present invention, a transfer film comprising a support layer 21 and two transfer layers is disclosed. It is understood 22 that the present invention also encompasses the use of 23 a support layer, as disclosed herein, having only one 24 or possibly more than two resin layers provided that at least one of the layers is thermally or electro-26 thermally transferable to another substrate, e.g., a 27 paper sheet.
28 The following examples further describe the 29 present invention.
A transfer sheet in accordance with this invention was prepared as follows.
A transfer sheet in accordance with this inven-tion was prepared as follows.
A stock solution (A-l) containing 27.5 grams Es-tane 5715 ~Polyurethane) sold by B. F. Goodrich Co., and 72.5 grams me-thyl ethyl ketone was mixed together and stirred until complete dissolution was achieved.
A second solution containing 10 grams of particulate graphite, sold as Micro 650 by Asbury Graphite, 90 grams resin solution, 40 grams methyl ethyl ke-tone, and 2.1 grams Byk SpecialTM sold by Mallinckrodt Chemical Company, was blended with the first solution in a chilled ~aring blender for 15 minutes and then allowed to settle for 15 minutes.
The resulting solution was coated on a release sheet with a gap coater to a dry thickness of 1.~1 mils, air dried for 5 minutes and then dried in an oven at 65C for 15 minutes.
Another solution (B) was prepared by intro-ducing 22.5 grams poly-n-butyl methacrylate, sold as ELVACITE 2044 by E. I. du Pont de Nemours & Co., and 74.4 grams TOLUSOL 25TM, sold by Shell Chemical Company, into an 8 oz. plastic bottle. The bottle was rolled on a jar null until the contents were dissolved. 7.5 grams Black Pearls L which is carbon black, sold by Cabot Corporation, and 600 grams of 1/4 stainless steel (Type 440) shot was added to the solution and the same was milled for 16 hours. The resulting solution was coated over the firs-t coating to a dry thickness of 0.5 ¦ mil using a Mayer rod (about # 22). The product was oven dried at 65C for 3 minutes.
2~
A final solution (C-l) was prepared by intro-ducing 25.0 grams Aquadag E (graphi-te dispersion, 22%
solids in water) and 75.0 grarns ethanol in an 8 oz.
bottle. The contents were stirred rapidly for 60 minutes with vortex blades. This solution was coated over the second coating (from solution B) to a dry thickness of 0~3 mil using a Mayer rod (about ~18) and oven dried at 65C for 3 minutes.
A -transfer sheet was prepared in accordance with Example 1 except that a solution (C-2) contain-ing 25.0 grams AQUABLACK 548-17TM (24% carbon black in water) or 428-238, sold by Borden Chemical Co., 2.0 grams Rhoplex P-376 (acrylic resin dispersion in water, 50% solids) and 27.0 grams water was sub-stituted for solution C-l and processed in the same manner as solution C-1.
6 2. Description of the Prior Art 7 In recent years, various systems have been 8 proposed for the rapid transmission and/or recording of g information. One such system is an electric discharge recording system.
11 The electric discharge recording system is a 12 process which comprises applying an electrical signal OL
13 several hundred volts and several watts in the form of 14 an electric voltage, and breaking a semiconductive recording layer on the surface of a recording layer by 16 electric discharge, thereby to form an image on the 17 recording layer or on a substrate superimposed on the 18 recording layer. This process is a "direct imaging"
19 process which does not require processing operations such as development and fixation, and is in widespread 21 use as a simple recording process. For example, the 22 process finds applications in facsimile systems, various 23 measuring instruments, recording meters, record displays 24 in computers, and processing of electrostencil master sheets 26 In the electric discharge recording, a dis-27 charge recording stylus is directly contacted with the 28 recording surface of an electric discharge recording 29 material. Discharging is performed through the stylus to break the recording layer, and to form an image on 31 the recording surface.
~, 1 A more recent development is disclosed by 2 Nakano et al in U.S. Patent 4,163,075 and relates to the 3 use of an electrosensitive transfer film. To record 4 with this type of film it is laid over an untreated sheet of a receiving medium, such as paper, and an 6 electric discharge stylus is moved in a regular pattern 7 across the back of the transfer film. Provision is 8 generally made to ground either one edge or the front g surface of the transfer film. When a voltage on the order of 150 to 200 volts is applied to the stylus, 11 current flows through the sheet and matter is caused to 12 be transferred to the receiving sheet, e.g., paper.
13 The film disclosed by Nakano et al in U.S.
14 Patent 4,163,075, comprises three layers, namely a film support layer and two transfer layers. The support 16 layer is composed of a metal powder-containing resin 17 layer, eOg., electrolytic copper powder having an 18 average diameter of 2 microns dispersed in a vinyl 19 chloride resin.
Numerous disadvantages appear to exist with 21 the use of the products disclosed in the Nakano et al 22 patent. For example, the use of small metal particles 23 in the support layer results in a high cost product 24 affecting the commercial success of the product. A
need therefore exists for a transfer sheet exhibiting 26 improved image quality that can be produced at a low 27 cost compared to other commercially available products~
29 It is an object of this invention to provide an electric discharge transfer film which is free from 31 the disadvantages described hereinabove.
1 According to the present invention, an elec-2 tric discharge recording material is provided which 3 comprises (a) an electrically anisotropic support 4 layer having electroconductive particles dispersed in a resin matrix wherein said electroconductive particles 6 are: (1) graphite particles having a particle size 7 between 0.1 to 20 microns, (2) carbon black particles 8 having a particle size between 25 to 500 millimicrons, g or (3) metal powders; and (b) at least one thermal or electrothermal transfer layer in the form of a resin 11 layer capable of being broken by electrical discharge 12 and transferred to a record sheet. A preferred resin 13 matrix comprises a phenoxy resin of the formula:
O = C ~ ~ O-C-C C
17 _ _ n 18 where n is about 100.
19 One embodiment of the present invention is an electric discharge recording material which comprises:
21 (a) a semiconductive resin layer capable of being 22 broken by electric discharging which has a surface 23 resistance of 105 to 1016 ohms and a volume resistance 24 of 103 to 1014 ohms-cm; (b) an electroconductive elec-trically anisotropic resin layer containing electro-26 conductive particles such as graphite, carbon black or 27 metal powders as described above, which is laminated on 28 one surface of the semiconductive resin layer (a); and 29 a conductive layer having a surface resistance of not more than 104 ohms and a volume resistance of not more 31 than 102 ohms-cm, which is laminated on the other 32 surface of the semiconductive resin layer (a).
1 Another embodiment of the present invention is 2 an electric discharge recording material which comprises 3 at least one resin layer capable of being thermally or 4 electrothermally transferable to another substrate, and an electrically anisotropic carbon black or graphite-h containing resin layer which is laminated on one surface 7 of one resin layer.
8 Still another embodiment of the present g invention is an electric discharge recording material, e.g., film, which comprises at least one resin layer 11 capable of being thermally or electrothermally trans-12 ferred to another substrate and an electrically aniso-13 tropic carbon black or graphite-containing support 14 layer. The graphite and carbon black particles exhibit particle sizes previously defined herein. The support 16 layer is laminated onto one surface of the resin layerO
17 Other objects, features and effects of this 18 invention will become more apparent from the following 19 detailed description considered with the drawings wherein:
21 Figure 1 is an expanded sectional view of the 22 transfer film of this invention.
24 The film structure, as illustrated in FIGURE
1, comprises an electrically anisotropic (unidirection-26 ally conductive) electroconductive particle-support 27 layer 2 and two transfer layers, namely layers 4 and 6.
28 When a graphite-containing resin is employed 29 as layer 2, it generally contains between 5 to 65% and preferably between 15 to 45% by weight graphite based 1 on the weight of the resin. Best results are obtained 2 when the layer contains between 25 and 35~ by weight 3 graphite, based on the weight of the resin. The par-4 ticle diameter of the graphite used in this layer is also critical to the successful practice of the ~ subject invention. Generally, the particle size is 7 generally between 0.1 to 20 microns, and preferably 8 between 0.1-5 microns, with best results being achieved g with particles between 0.1 and 1 microns.
According to an embodiment of this invention, 11 graphite particles useful in the anisotropic support 12 layer can be prepared by grinding the graphite particles 13 in the presence of water or other solvent having sub-14 stantially the same freezing and vapor pressure proper-ties as water, e.g., tertiary butyl alcohol, cyclohexane, 16 benzene, dioxane, and para-xylene. Generally~ between 17 about 70 and 80% by weight of the slurry is water or 18 solvent, as defined herein, the balance being solids, 19 namely the graphite particles. It is understood that the amount of water or solvent employed is not 21 critical and can vary over wide ranges both below 70%
22 and above 80% because the solvent or water is eventually 23 driven off in accordance with this process. Grinding 2~ takes place for a period of time sufficient to achieve substantially complete dispersion of the graphite 26 particles in the solvent or water. Generally, such 27 grinding takes place between 8 and 16 hours to achieve 28 the substantial dispersion of the graphite particles.
29 The term "substantial", as used in this context, means at least 95% of the graphite being dispersed in the 31 water or solvent with as little as possible agglomeri-32 zation of the graphite being present. Grinding is 33 generally accomplished by subjecting the slurry to a 34 ball mill, sand mill or any other clispersion technique well~known to those of ordinary skill in the art. It is particularly preferred -to reduce agglomera-tes of graphite and to obtain substantial dispersion of the graphite particles with an "ATTRITOR" , Model 01, made by Union Process Company, Dayton, Ohio.
A binding polymer is added to the graphite slurry, either during the grinding step or immediately after the grinding step for the purpose of forming a film or coating on the individual particles of graphite.
The polymer employed is to be soluble in the water or solvent of the slurry. Suitable polymers include, e.g., polyvinyl alcohol, gelatin or methyl cellulose.
Freezing of the slurry is achieved by lower-ing the temperature to a point wherein the physical state of the solvent changes from liquid to solid.
The frozen slurry is then dried, under conditions such that the water solvent present is caused to sublime, i.e., the solid is directly converted to the vapor form, without passage through the liquid state. The process results in the formation of a sub-stantial amount of undamaged polymeric coated graphite particles having a diameter of at least 0.2 microns.
By substantial amount, it is intended that a-t least 90% of the particles have a diameter of at least 0.2 microns.
Sublimation of water, or other solvents used in place of wa-ter, which exists in the solid s-tate, can be caused to change to a gaseous phase without an intermediate phase, under well-known changes in pres-sure alone, tempera-ture alone, or a change in both temperature and pressure. Generally, sublimation can be produced under the influence of a high-pressure vacuum.
It is critical that the graphite particles be dispersed in the resin in such a manner the graphi-te is ~D~Z~
not reduced in size to dust particles (under 0.1 micron).
Graphite particles are therefore dispersed in a resin, generally in a mol-ten state, by means of a high sheer blender, e.g., a Waring blender, Cowl or Greer blenders, rather than by impact grinding methods, e.g., ball milling or dispersing in an attritor. The latter methods cause the graphite particles to greak up into particles less than 0.1 micron size, adversely affect-ing the electrically anisotropic properties of the layer.
When the electroconductive particles are carbon black particles, the electrically conductive carbon-black-containing resin of layer 2 contains generally between 60 to 70% by weight carbon black.
Best results are obtained when the layer contains 65%
by weight carbon black, based on the weight of the resin and carbon black. The particle diameter of the carbon black used in this layer is also eritieal to the successful practice of the subject invention. Gener-ally, the partiele size is generally between 25 and500 millimierons, with best results being aehieved with partieles of about 350 millimierons.
Carbon blaek is available from numerous commercial sources. For the present invention, channel blacks, ~urnace blacks, and thermal blacks are useful in the practice of the invention. Examples of suit-able earbon blaeks inelude those sold under the mark T~RMAXTM
The resin whieh eonstitutes the resin matrix in whieh the elec-troeonduetive partieles of the aniso-tropie layer are dispersed may be any thermoplastic or thermosetting resin whieh has film-forming ability and eleetrieal insulation (generally having a volume resis-tanee of at least 107 ohms-em). Generally, the matrix resin preferably has a great ability to bind the elec-tro-conductive particle and can be formed into sheets or films having high mechanical strength, flexibility and high stiffness.
A preferred resin that is useful in the resin matrix, in which the electro-conductive particles are dispersed, is a phenoxy resin of the formula:
{ O \ ~ C ~ O-C-C-C n wherein n is about 100.
A suitable phenoxy resin is sold by Union Carbide Corporation under the trademark "PKH~I"
This resin has the following characteristics:
Approximate Molecular Weight 20,000 to 30,000 Specific Gravity 1.18 Melt Flow (g/10 minutes at 220C) 2.5-10 Ultimate Tensile Strength, psi 9,000-9,500 Ultimate Tensile Elongation 50-100 Softening Temperature 100C
Moisture Vapor Transmission 3.5 gms/mil/
24 hrs/100 in.
Molecular Structure As shown above Generally, the matrix resin preferably has a great ability to bind the elec-troconductive particles, e.g., graphite, carbon black or the metal powders disclosed in U. S. Patent ~,163,075 or other useful electroconductive particles that may be used. These resins can be formed into sheets or films having high mechanical strength, flexibility and high stiffnessO
1 Examples oE suitable resins that can be used 2 in this invention are thermoplastic resins such as 3 polyolefins (such as polyethylene or polypropylene), 4 polyvinyl chloride, polyvinyl acetal, cellulose acetate, polyvinyl chloride, polyvinyl acetal, cellulose acetate, 6 polyvinyl acetate, polystyrene, polymethyl acrylate, 7 polymethyl methacrylate, polyacrylonitrile, thermo-8 plastic polyesters, polyvinyl alcohol, and gelatin; and g thermosetting resins such as thermosetting polyesters, epoxy resins, and melamine resins. The thermoplastic 11 resins are preferred, and polyethylene, polyvinyl 12 acetal, cellulose acetate, and thermoplastic polyesters 13 are especially preferred.
1~ As is conventional in the art, additives such as plasticizers, fillers, lubricants, stabilizers, 16 antioxidants or mold releasing agents may be added as 17 needed to the resin in order to improve its moldability, 18 storage stability, plasticity, tackiness, lubricity, 19 etc.
Examples of the plasticizers are dioctyl 21 phthalate, dibutyl phthalate, dicapryl phthalate, 22 dioctyl adipate, diisobutyl adipate, triethylene glycol 23 di(2-ethyl butyrate), dibutyl sebacate, dioctyl azelate, 2~ and triethylhexyl phosphate, which are generally used as plasticiæers for resins. The amount of the plasticizer 26 can be varied over a wide range according, for example, 27 to the type of the resin and the type of the plasticizer 28 Generally, its amount is at most 150 parts by weight, 29 preferably up to 100 parts by weight, per 100 parts by weight of the resin. The optimum amount of the 31 plasticizer is not more than 80 parts by weight per 100 32 parts by weight of ~he resin.
1 Examples of fillers are fine powders of 2 calcium oxide, magnesium oxide, sodium carbonate, 3 potassium carbonate, strontium carbonate, zinc oxide, 4 titanium oxide, barium sulfate, lithopone, basic mag-nesium carbonate, calcium carbonate, silica, and kaolin.
6 They may be used either alone or as mixtures of two or 7 more.
8 The amount of the filler is not critical, and 9 can be varied over a wide range according to the type of the resin, the type of the filler, etc. Generally, the 11 amount is up to 1000 parts by weight, preferably not 12 more than 500 parts by weight, more preferably up to 200 13 parts by weight.
14 Usually its thickness is at least 3 microns.
The upper limit of the thickness is not strict, but is 16 advantageously set at 100 microns for the reason stated 17 above. Preferably, the thickness is 5 to 60 microns, 18 more preferably 10 to 40 microns.
19 The semiconductive resin layer 4 laminated on the electroconductive particle-containing resin layer is 21 broken by discharging. It has a surface resistance of 22 10 to 109 ohms, preferably 103 to 107 ohms, more prefer-23 ably 104 to 1o6 ohms and a volume resistance of 11 to 24 106 ohms-cm, preferably 11 to 105 ohms-cm, more prefer-ably 102 to 104 ohms-cm.
26 The semiconductive resin layer ~ can be formed 27 by dispersing a conductivity-imparting agent in a resin 28 matrix.
29 The resin matrix forming a substrate for the semiconductive resin layer 4 may be chosen from those 31 which have been described hereinabove about the non-1 recording layer composed of an electroconductive par-2 ticle-containing resin. The thermoplastic resins are 3 especially suitable, and polyethylene, cellulose acetate 4 and polyvinyl acetal are used advantageously~ As needed, the resin may contain additives of the types 6 described hereinabove such as plasticizers and fillers 7 in the amounts described.
8 When a filler having a different conductivity g from the conductivity-imparting agent, generally having a lower conductivity than the conductivity-imparting 11 agent, is included in the semiconductive resin layer 4, 12 the breakdown of the semiconductive resin layer 4 by 13 electric discharging occurs more sharply, and a recorded ]4 image which is clearer and has a higher contrast can be obtained. Suitable fillers of this kind are fine 16 powders of inorganic substances such as magnesium oxide, 17 calcium oxide, sodium carbonate, potassium carbonate, 18 strontium carbonate, titanium oxide, barium sulfate, 19 lithopone, basic magnesium carbonate, calcium carbonate, silica, kaolin clay, and zinc oxide. They can be used 21 singly or as a mixture of two or more. Of these, 22 titanium oxide and calcium carbonate are especially 23 suitable. The average particle diameter of the filler 24 is generally 10 microns at most, preferably not more than 5 microns, more preferably 2 to 0.1 microns. The 26 amount of the filler can be varied over a wide range 27 according to the type of the resin, etc. The suitable 28 amount is generally 10 to 2,000 parts by weight, prefer-29 ably 20 to 1,000 parts by weight, more preferably 50 to 400 parts by weight, per 100 parts by weight of the 31 resin.
32 The conductivity-imparting agent to be dis-33 persed in the resin to impart semiconductivity may be 34 any material which has conductivity and gives the 1 surface resistance and volume resistance described above 2 to the resin layer. Generally, suitable conductivity-3 imparting agents have a specific resistance, measured 4 under a pressure of 50 kg/cm2, of not more than 106 ohms-cm. Examples of such a conductivity-imparting 6 agent include carbon blacks; metals such as gold, 7 silver, nickel, molybdenum, copper, aluminum, iron 8 and conductive zinc oxide (zinc oxide doped with 0.03 g to 2.0% by weight, preferably 0.05 to 1.0% by weight, based on the zinc oxide, of a different metal such as 11 aluminum, gallium, germanium, indium, tin, antimony or 12 iron); conductive metal-containing compounds such as 13 cuprous iodide, stannic oxide, and metastannic acid; and 14 zeolites. Of these, carbon blacks, silver, nickel, suprous iodide, conductive zinc oxide are preferred, 16 and carbon blacks and conductive zinc oxide are more 17 preferred. The carbon blacks which also act as a 18 coloring agent are most preferred.
19 Carbon blacks differ somewhat in conductivity according to the method of productionO Generally, 21 acetylene black, furnace black, channel black, and 22 thermal black can be used.
23 The conductivity-imparting agent is dispersed 24 usually in the form of a fine powder in the resin. The average particle diameter of the conductivty-imparting 26 agent is 10 microns at most, preferably not more than 5 27 microns, especially preferably 2 to 0.005 microns. When 28 a metal powder is used as the conductivity-imparting 29 agent, it is preferably in a microspherical, dendric or microlumpy form. Moreover, since a resin sheet 31 having the metal powder dispersed therein tends to be 32 electrically anisotropic if its particle diameter 33 exceeds 0.2 micron. ~lence, the particle size of a metal 34 powder in the above-mentioned form to be used as a 1 conductivity-imparting agent for the semiconductive 2 resin layer 4 or the conductive layer 6 should be at 3 most 0.5 micron, preferably not more than 0.2 micron, 4 more preferably 0.15 to 0.04 micron. Scale-like or needle-like powders can also be used, but should be 6 combined with powders of the above forms.
7 The amount of the conductivity-imparting agent 8 to be added to the resin can be varied over a very wide g range according to the conductivity of the conductivity-imparting agent, etc. The amount is that sufficient 11 to adjust the surface resistance and volume resistance 12 f the semiconductive resin layer 4 to the above-13 mentioned ranges. For example, carbon blacks are 14 incorporated generally in an amount of 1 to 300 parts by weight, preferably 2 to 200 parts by weight, more 16 preferably 3 to 150 parts by weight, per 100 parts by 17 weight of the resin. The other conductivity-imparting 18 agents are used generally in an amount of 3 to 500 parts 19 by weight, preferably 5 to 400 parts by weight, more preferably 10 to 300 parts by weight, per 100 parts by 21 weight of the resin.
22 The thickness of the semiconductive resin 23 layer 4 is not critical, and can be varied over a wide 24 range according to the uses of the final product, etc. Generally, its thickness is at least 2 microns, 26 preferably 3 to 50 microns, more preferably 5 to 20 27 micronS.
28 According to the present invention, the 29 conductive layer 6 is laminated on the other surface of the semiconductive resin layer 4.
31 The conductive layer 6 plays an important role 32 in performing electric discharge breakdown with high 1 accuracy by converging the current flowing through the 2 semiconductive resin layer at a point immediately 3 downward of the electric discharge recording stylus.
~ The conductive layer 6 has a surface resistance of not more than 104 ohms, preferably not more than 5 x 103 6 ohms, more preferably 10~1 to 2 x 103 ohms and a volume 7 resistance of not more than 102 ohms-cm, preferably not 8 more than 50 ohms-cm, more preferably not more than 20 g ohms-cm.
The conductive layer 6 having such resistance 11 characteristics may be a conductive resin layer com-12 prising a thermoplastic or thermosetting resin and a 13 conductivity-imparting agent dispersed in it, a vacuum-14 deposited metal layer, or a metal foil layer.
The thermoplastic or thermosetting resin that 16 can be used in the conductive resin layer can also be 17 selected from those described hereinabove in connection 18 with the non-recording layer. Of these, the thermo-19 plastic resins, especially polyethylene, cellulose acetate and polyvinyl acetal, are used advantageously.
21 The conductivity-imparting agent to be dispersed in the 22 resin may be chosen from those described above in 23 connection with the semiconductive resin layer. Carbon 24 blacks and metal powders are especially suitable~
Carbon blacks are particularly preferred over metals in 26 view of cost factors.
27 The conductivity-imparting agents are added in 28 amounts which will cause the resin layer to have the 29 electrical resistance characteristics described above.
The amounts vary greatly according to the type of the 31 conductivity-imparting agent. For example, carbon 32 blacks are used in an amount of generally at least 10 33 parts by weight, preferably 20 to 200 parts by weight, 1 more preferably 30 to 100 parts by weight; the other 2 conductivity-imparting agents especially metal powders, 3 are used in an amount of at least 50 parts by weight, 4 preferably 100 to 600 parts by weight, more preferably 150 to 400 parts by weight, both per 100 parts by weight 6 of the resin.
7 As needed, the conductive resin layer may 8 contain the aforesaid additives such as plasticiæers and g fillers in the amounts stated.
The thickness of the conductive resin layer is 11 not critical, and can be varied widely according to the 12 uses of the final products, etc. Generally, it is at 13 least 3 microns, preferably 3 to 50 microns, more 14 preferably 5 to 20 microns.
The conductive layer 6 may be a vacuum 16 deposited metal layer. Specific examples of the metal 17 are aluminum, zinc, copper, silver and goldO Of these, 18 aluminum is most suitable.
19 The thickness of the vacuum-deposited metal layer is not critical. Generally, it is at least 4 21 millimicrons, preferably 10 to 300 millimicrons, 22 more preferably 20 to 100 millimicrons. By an ordinary 23 vacuum-depositing method for metal, it can be applied to 24 one surface of the semiconductive resin layer 4.
The conductive layer 6 may also be a thin 26 metal foil, for example, an aluminum foil. It can be 27 applied to one surface of the semiconductive resin layer 28 4 by such means as bonding or plating.
29 It is understood that at least one of the layers 4 and 6 may contain a coloring substance. Useful 1 coloring substances are carbon black, inorganic and 2 organic pigments, and dyes.
3 Carbon black has superior conductivity and 4 acts both as a coloring substance and a conductivity-imparting agent as stated above. Thus, when the semi-6 conductive resin layer or the conductive resin layer 7 already contains carbon ~lack as a conductivity-impart-8 ing agent, it is not necessary to add a further coloring 9 substance. The inclusion of other suitable coloring substance is of course permissible.
11 Examples of pigments other than carbon black 12 include inorganic pigments such as nickel yellow, 13 titanium yellow, cadmium yellow, zinc yellow, ochre, 14 cadmium red, prussian blue, ultramarine blue, zinc white, lead sulfate, lithopone, titanium oxide, black 16 iron oxide, chrome orange, chrome vermilion, red iron 17 oxide, red lead and vermilion, and organic pigments of 18 the phthalocyanine, quinacridone and benzidine series 19 such as aniline black, naphthol yellow S, hanza yellow 10G, benzidine yellow, permanent yellow, Permanent 21 Orange, Benzidine Orange G, Indanthrene Brilliant Orange 22 GK, Permanent Red 4R, Brilliant Fast Scarlet, Permanent 23 Red F2R, Lake Red C, Cinquasia Red Y (Dup) (C. I. 46500), 24 Permanent Pink E (F~l) [Quido Magenta RV 6803(~AR)], and Phthalocyanine Blue (C.I. Pigment Blue 15).
Examples of useful dyes are azoic dyes, 27 anthraquinonic dyes, thionidigo dyes, quinoline dyes, 28 and indanthrene dyes.
29 The pigments and dyes described are used either alone or in combination according to the color 31 desired to be formed on a transfer recording sheet.
1 The amount of the pigment or dye can be varied 2 over a wide range according to the type, color intensity, 3 etc. of the coloring substanceO Generally, it is at 4 least 1 part by weight, preferably 2 to 1,000 parts by weight, more preferably 3 to 500 parts by weight, per 6 100 parts by weight of the resin.
7 When the pigment or dye is to be incorporated 8 in both of the semiconductive resin layer 4 and the g conductive resin layer 6, it is desirable that pigments or dyes be of an identical color or have colors of the 11 same series.
12 The composite electric discharge recording 13 material of this invention can be formed by known 14 methods, for example a melt-extrusion method, a melt-coating method, a melt-calendering method, a solution 16 casting method, an emulsion casting method or combi-17 nations of these methods.
18 The composite electric discharge recording 19 material of this invention described above is useful as an electric discharge transfer recording material or an 21 electric stencil master sheet.
22 The electric discharge transfer recording 23 mediums of the present invention are generally employed 24 by superimposing the transfer recording medium onto a recording sheet 8, e.g., cellulosic paper, a synthetic 26 paper-like sheet or a plastic sheet so that the conduc-27 tive layer 6 contacts recording sheet 8. When electric 28 discharge recording is performed by a discharge record-29 ing stylus in accordance with an ordinary method from the side of the electroconductive powder-containing 31 resin layer 2, the semiconductive resin layer 4 and the 32 conductive layer 6 are simultaneously broken by electric .~f~
1 discharging, and the broken pieces 10 are transferred to 2 the record sheet and fixed thereon, thereby achieving 3 transfer recording.
9 According to a further embodiment of the present invention, a color coupler may be put in one or 6 more transfer layers to react with a material in the 7 recording material or paper, to generate a colored 8 image, e.g., bisphenol A and leuco dye.
g It is understood that the electric discharge transfer film of this invention can be processed to any 11 desired width or length in accordance with its desired 12 use. For example, the transfer film can be used in the 13 form of a narrow tape, such as a typewriter ribbon.
14 In electric discharge recording, the semi-conductive resin layer and the conductive layer of the 16 composite electric discharge transfer recording material 17 are broken down, but the electroconductive powder-18 containing resin layer is not broken because of its 19 electric anisotropy and remains substantially unchanged.
Accordingly, dissipation of any offensive odor issued 21 at the time of electric discharge breakdown is inhibited, 22 and soot or a coloring substance such as carbon black is 23 prevented from scattering and adhering to the discharge 24 recording stylus. The troublesome inspection and maintenance of the discharge recording stylus can be 26 markedly reduced, and recording can be performed with 27 high reliability. The term "electrical anisotropy"
28 refers to the low resistance of support layer or 29 electroconductive particle containing resin layer 2 in the through direction and the high resistance of this 31 layer in the lateral direction.
1 The use of the composite electric discharge 2 recording material can afford a sharp recorded image, 3 and in electric discharge transfer recording, a transfer 4 recorded image having a high density, a natural appear-ance and a soft tone can be obtained.
6 The composite electric discharge recording 7 material of this invention can be used a plurality of 8 times.
9 The composite electric discharge recording material of this invention can be conveniently used 11 in facsimile systems, terminal recording devices in 12 electronic computers, automatic recording devices of 13 automatic measuring instruments, and various types of 14 printers, etc.
In the present specification, the terms 16 "surface resistance" and "volume resistance" is deter-17 mined in accordance with the method described by H. R.
18 Dalton in U.S. Patent 2,664,044.
19 In the detailed description of the present invention, a transfer film comprising a support layer 21 and two transfer layers is disclosed. It is understood 22 that the present invention also encompasses the use of 23 a support layer, as disclosed herein, having only one 24 or possibly more than two resin layers provided that at least one of the layers is thermally or electro-26 thermally transferable to another substrate, e.g., a 27 paper sheet.
28 The following examples further describe the 29 present invention.
A transfer sheet in accordance with this invention was prepared as follows.
A transfer sheet in accordance with this inven-tion was prepared as follows.
A stock solution (A-l) containing 27.5 grams Es-tane 5715 ~Polyurethane) sold by B. F. Goodrich Co., and 72.5 grams me-thyl ethyl ketone was mixed together and stirred until complete dissolution was achieved.
A second solution containing 10 grams of particulate graphite, sold as Micro 650 by Asbury Graphite, 90 grams resin solution, 40 grams methyl ethyl ke-tone, and 2.1 grams Byk SpecialTM sold by Mallinckrodt Chemical Company, was blended with the first solution in a chilled ~aring blender for 15 minutes and then allowed to settle for 15 minutes.
The resulting solution was coated on a release sheet with a gap coater to a dry thickness of 1.~1 mils, air dried for 5 minutes and then dried in an oven at 65C for 15 minutes.
Another solution (B) was prepared by intro-ducing 22.5 grams poly-n-butyl methacrylate, sold as ELVACITE 2044 by E. I. du Pont de Nemours & Co., and 74.4 grams TOLUSOL 25TM, sold by Shell Chemical Company, into an 8 oz. plastic bottle. The bottle was rolled on a jar null until the contents were dissolved. 7.5 grams Black Pearls L which is carbon black, sold by Cabot Corporation, and 600 grams of 1/4 stainless steel (Type 440) shot was added to the solution and the same was milled for 16 hours. The resulting solution was coated over the firs-t coating to a dry thickness of 0.5 ¦ mil using a Mayer rod (about # 22). The product was oven dried at 65C for 3 minutes.
2~
A final solution (C-l) was prepared by intro-ducing 25.0 grams Aquadag E (graphi-te dispersion, 22%
solids in water) and 75.0 grarns ethanol in an 8 oz.
bottle. The contents were stirred rapidly for 60 minutes with vortex blades. This solution was coated over the second coating (from solution B) to a dry thickness of 0~3 mil using a Mayer rod (about ~18) and oven dried at 65C for 3 minutes.
A -transfer sheet was prepared in accordance with Example 1 except that a solution (C-2) contain-ing 25.0 grams AQUABLACK 548-17TM (24% carbon black in water) or 428-238, sold by Borden Chemical Co., 2.0 grams Rhoplex P-376 (acrylic resin dispersion in water, 50% solids) and 27.0 grams water was sub-stituted for solution C-l and processed in the same manner as solution C-1.
Claims (12)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An electric discharge transfer material characterized by comprising:
(a) an electrically anisotropic support layer having electroconductive particles dispersed in a resin matrix wherein said electroconductive particles are:
(1) graphite particles having a particle size between 0.1 to 20 microns, (2) carbon black particles having a particle size between 25 to 500 millimicrons, or (3) metal powders; and (b) at least one thermal or electrothermal transfer layer in the form of a resin layer capable of being broken by electrical discharge and transferred to a record sheet.
(a) an electrically anisotropic support layer having electroconductive particles dispersed in a resin matrix wherein said electroconductive particles are:
(1) graphite particles having a particle size between 0.1 to 20 microns, (2) carbon black particles having a particle size between 25 to 500 millimicrons, or (3) metal powders; and (b) at least one thermal or electrothermal transfer layer in the form of a resin layer capable of being broken by electrical discharge and transferred to a record sheet.
2. An electric discharge transfer material according to claim 1 further characterized by comprising:
(a) a semiconductive resin layer capable of being broken by electric discharging which has a surface resistance of 105 to 1016 ohms and a volume resistance of 103 to 1014 ohms-cm;
(b) an electroconductive electrically aniso-tropic resin layer containing said electroconductive particles, said electroconductive resin layer being laminated on one surface of the said semiconductive resin layer (a), and (c) a conductive layer having a surface re-sistance of not more than 104 ohms and a volume resistance of not more than 102 ohms-cm, said con-ductive layer being laminated on the other surface of the said semiconductive resin layer.
(a) a semiconductive resin layer capable of being broken by electric discharging which has a surface resistance of 105 to 1016 ohms and a volume resistance of 103 to 1014 ohms-cm;
(b) an electroconductive electrically aniso-tropic resin layer containing said electroconductive particles, said electroconductive resin layer being laminated on one surface of the said semiconductive resin layer (a), and (c) a conductive layer having a surface re-sistance of not more than 104 ohms and a volume resistance of not more than 102 ohms-cm, said con-ductive layer being laminated on the other surface of the said semiconductive resin layer.
3. An electric discharge transfer material according to claim 2 further characterized in that at least one of the semiconductive resin layer (a) and the conductive layer (c) contains a coloring substance.
4. An electric discharge transfer material according to claim 3 further characterized in that the coloring substance is carbon black.
5. An electric discharge transfer material according to claim 4 further characterized in that the semiconductive resin layer capable of being broken by electric discharging comprises a thermo-plastic or thermosetting resin and carbon black and a filler dispersed therein.
6. An electric discharge transfer material according to claim 5 further characterized in that the said electrically anisotropic resin layer com-prises between 60 to 70% by weight carbon black having a particle size between 25 and 500 milli-microns, based on the total weight of the resin and carbon black.
7. An electric discharge transfer material according to claim 5 further characterized in that the said electrically anisotropic resin layer comprises between 5 and 65% by weight graphite having a particle size between 0.1 and 20 microns, based on the weight of the resin.
8. An electric discharge transfer material according to any one of claims 6 or 7 further com-prising said resin matrix comprises a phenoxy resin of the formula:
wherein n is about 100.
wherein n is about 100.
9. A method for making an electrically aniso-tropic support layer useful in the electric discharge transfer materials characterized by comprising the steps of:
(a) grinding a slurry of graphite particles in the presence of water or solvent having freezing and vapor pressure properties similar to water for a period of time sufficient to substantially completely disperse the graphite particles in said water or solvent, (b) adding a binding polymer to said graphite slurry, either as part of step (a) or immediately after step (a), wherein said polymer is soluble in said water or solvent, (c) freezing said slurry;
(d) drying said slurry wherein said water or solvent present is caused to sublime resulting in the formation of polymeric coated graphite particles wherein at least a substantial portion of these par-ticles have a diameter of at least 0.2 microns, and (e) casting said coated graphite particles into a support layer for an electroconductive transfer film.
(a) grinding a slurry of graphite particles in the presence of water or solvent having freezing and vapor pressure properties similar to water for a period of time sufficient to substantially completely disperse the graphite particles in said water or solvent, (b) adding a binding polymer to said graphite slurry, either as part of step (a) or immediately after step (a), wherein said polymer is soluble in said water or solvent, (c) freezing said slurry;
(d) drying said slurry wherein said water or solvent present is caused to sublime resulting in the formation of polymeric coated graphite particles wherein at least a substantial portion of these par-ticles have a diameter of at least 0.2 microns, and (e) casting said coated graphite particles into a support layer for an electroconductive transfer film.
10. A method according to claim 9 further char-acterized by solvent casting said coated graphite particles into a support layer for an electroconduc-tive transfer film.
11. A method according to claim 10 further characterized in that the said water-soluble or solvent soluble binding polymer is polyvinyl alcohol, gelating or methyl cellulose.
12. A method according to any one of claims 9, 10 or 11 further characterized in that the said sol-vent is t-butyl alcohol, cyclohexane, benzene, dioxane, or p-xylene.
Applications Claiming Priority (8)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US39510282A | 1982-07-06 | 1982-07-06 | |
| US39510182A | 1982-07-06 | 1982-07-06 | |
| US395,584 | 1982-07-06 | ||
| US395,102 | 1982-07-06 | ||
| US06/395,584 US4454194A (en) | 1982-07-06 | 1982-07-06 | Lyophilization process for preparing composite particles for use in electroconductive transfer films and products produced therewith |
| US395,101 | 1982-07-06 | ||
| US06/395,103 US4482599A (en) | 1982-07-06 | 1982-07-06 | Support layer for electric discharge transfer materials |
| US395,103 | 1982-07-06 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1192046A true CA1192046A (en) | 1985-08-20 |
Family
ID=27503372
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000431885A Expired CA1192046A (en) | 1982-07-06 | 1983-07-06 | Electrosensitive transfer film |
Country Status (2)
| Country | Link |
|---|---|
| EP (1) | EP0099228A3 (en) |
| CA (1) | CA1192046A (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE68922604T2 (en) * | 1988-09-24 | 1996-02-01 | Dainippon Printing Co Ltd | Electrically conductive thermal transfer belt. |
| JP3356079B2 (en) * | 1998-10-12 | 2002-12-09 | ソニーケミカル株式会社 | Light-blocking anisotropic conductive adhesive film and liquid crystal display device |
| US6346350B1 (en) * | 1999-04-20 | 2002-02-12 | Celgard Inc. | Structurally stable fusible battery separators and method of making same |
| US6632400B1 (en) * | 2000-06-22 | 2003-10-14 | Agilent Technologies, Inc. | Integrated microfluidic and electronic components |
| US7582403B2 (en) * | 2006-07-17 | 2009-09-01 | E. I. Du Pont De Nemours And Company | Metal compositions, thermal imaging donors and patterned multilayer compositions derived therefrom |
| US8062824B2 (en) * | 2006-07-17 | 2011-11-22 | E. I. Du Pont De Nemours And Company | Thermally imageable dielectric layers, thermal transfer donors and receivers |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1545726A (en) * | 1976-07-08 | 1979-05-16 | Sekisui Chemical Co Ltd | Electric discharge recording method and material |
| US4264913A (en) * | 1976-07-08 | 1981-04-28 | Sekisui Kagaku Kogyo Kabushiki Kaisha | Electric discharge recording method and material with non-recording layer |
| US4308314A (en) * | 1978-08-04 | 1981-12-29 | Sekisui Kagaku Kogyo Kabushiki Kaisha | Electric recording material |
| US4269892A (en) * | 1980-02-04 | 1981-05-26 | International Business Machines Corporation | Polyester ribbon for non-impact printing |
| DE3218732A1 (en) * | 1981-05-20 | 1982-12-09 | Ricoh Co., Ltd., Tokyo | RIBBON FOR ELECTROTHERMAL IMPACT-FREE RECORDING |
-
1983
- 1983-07-05 EP EP83303906A patent/EP0099228A3/en not_active Withdrawn
- 1983-07-06 CA CA000431885A patent/CA1192046A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| EP0099228A3 (en) | 1985-05-15 |
| EP0099228A2 (en) | 1984-01-25 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP0008198B1 (en) | Electric recording material and method of electric recording | |
| US4163075A (en) | Electric discharge recording material | |
| EP0109295B1 (en) | Dye transfer sheets for heat-sensitive recording | |
| JPH0675999B2 (en) | Sliding layer containing granular ester wax for use in dye-donor element for thermal dye transfer | |
| EP0099227A2 (en) | Electrosensitive transfer material | |
| CA1192046A (en) | Electrosensitive transfer film | |
| US4454194A (en) | Lyophilization process for preparing composite particles for use in electroconductive transfer films and products produced therewith | |
| US4482599A (en) | Support layer for electric discharge transfer materials | |
| US4415903A (en) | Electric ink transfer recording method | |
| US4264913A (en) | Electric discharge recording method and material with non-recording layer | |
| EP0384783B1 (en) | Method of manufacturing a ribbon for non-impact printing of documents | |
| US4403232A (en) | Electrosensitive recording paper having improved recording density | |
| JPS59145257A (en) | Manufacture of non-metal electroconductive particle and discharge transfer material | |
| JPH0356676B2 (en) | ||
| JP2722191B2 (en) | Thermal transfer film | |
| JP3711641B2 (en) | Photographic paper for thermal transfer | |
| EP0310141B1 (en) | Multiple-use pressure-sensitive transfer recording media | |
| JPS61258791A (en) | Black color thermal transfer recording sheet | |
| JPH0356553B2 (en) | ||
| JPH0630970B2 (en) | Transfer type thermal recording sheet | |
| JPS6250191A (en) | Energization thermal transfer recording | |
| JPS5830157B2 (en) | discharge recording material | |
| JPH0356675B2 (en) | ||
| JPH0226786A (en) | Ink medium | |
| JPH0356554B2 (en) |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEC | Expiry (correction) | ||
| MKEX | Expiry |