US3891513A

US3891513A - Electrical coloration recording sheet

Info

Publication number: US3891513A
Application number: US383160A
Authority: US
Inventors: Akiyoshi Yasumori; Katsuichi Ohta; Makoto Kunikane; Michiharu Abe
Original assignee: Ricoh Co Ltd
Current assignee: Ricoh Co Ltd
Priority date: 1972-08-08
Filing date: 1973-07-27
Publication date: 1975-06-24
Anticipated expiration: 1992-06-24
Also published as: JPS4937650A; DE2340014A1

Abstract

A thin electrically conductive material layer is provided on an electrical coloration material layer of the sheet. Upon scanning the thin conductive material layer by a recording electrode, it is possible to produce a recorded likeness of the original on the sheet by information signals as the color image of the electrical coloration material is controlled by the signals.

Description

United States Patent n91 Yasumori et a1.

June 24, 1975 ELECTRICAL COLORATION RECORDING SH EET Inventors: Akiyoshi Yasumori; Katsuichi Ohta,

both of Yokohama} Makoto Kunikane, Tokyo; Michiharu Abe, Kawasaki, all of Japan Assignee: Ricoh Co., Ltd., Tokyo, Japan Filed: July 27, 1973 Appl. No.: 383,160

Foreign Application Priority Data Aug. 8, 1972 Japan 47-79260 US. Cl 204/2; 346/74 E; 346/76;

346/135 Int. Cl. 841m 5/20; GOld 15/34 Field of Search 204/2; 178/62; 96/1 E;

346/74 CH, 74 E, 135, 76

[56] References Cited UNITED STATES PATENTS 2,554,017 5/1951 Dalton 204/2 3,299,433 1/1967 Reis l 204/2 3.689,768 9/1972 Sato 346/135 3,786,518 1/1974 Atherton 1 346/135 3,789,425 1/1974 Matsushima 346/135 Primary Examiner- T. M. Tufariello Attorney, Agent, or Firm-Cooper, Dunham, Clark, Griffin & Moran [57] ABSTRACT 16 Claims, 2 Drawing Figures INFORMATION SIGNAL I PATENTEDJuu24 ms 3.891, 513

FIG. I PRIOR ART 'IIIIIIIIIIIIIIIIIIIIIIIIIIJ ELECTRICAL COLORATION RECORDING SHEET BACKGROUND OF THE INVENTION This invention relates to an electrical coloration recording sheet capable of electrically producing a recorded likeness of an original thereon.

in producing a recorded likeness of an original by, .g., a facsimile receiver or an output device of a com puter, it is needed to use sheets responding to electricity which are easy to handle, high in the degree of precision and low in running cost while permitting high speed production of a recorded likeness of the original to be carried out.

Heretofore, in the facsimile system, for example, it has been customary to employ an electrolytic recording process, electrical discharge recording process or an electrostatic recording process to produce a facsimile record of an original from electric signals. However, none of these processes meet the aforementioned requirements.

The electrolytic recording process employs a recording sheet produced by impregnating paper or other like material with polyhydric phenol and an anode made of iron. A voltage is impressed on the recording sheet while the latter is in moist condition to produce a brown image by electrolysis. This process has disadvantages. Since the recording sheet should be wet in operation, difficulty is experienced in handling the sheet. The use of wet sheets often leads to corrosion of parts of the apparatus. Besides, the images formed on the sheets of this type leave much to be desired in tone, contrast, resolution and longevity.

In the sparking recording process, a white colored material layer formed by applying to a carbon layer of a supporter of a recording sheet a titanium oxide mixed with a resin supporter is subjected to a discharge of high voltage so as to destroy portions of the white colored material layer and expose the underlying carbon layer, so that an image of the original can be produced on the recording sheet. Some disadvantages are associated with this process. The use of a current of high voltage makes it necessary to take special precaution in operation. The resin binder is burned when the white colored material layer is destroyed and produces odor. Portions of the white colored material layer are destroyed and adversely affect the apparatus. The recording sheet itself is fragile and difficult to handle because it consists of many layers. The images formed on the recording sheets of this type lack harmony.

The electrostatic recording process is such that a voltage is impressed as by a contact electrode on a recording sheet comprising a dielectric material layer formed on a supporter which may be paper or other like material treated to be electrically conductive so as to form on the recording sheet an electrostatic latent image which is developed into a visible image. The need to develop the latent image into a visible image entails the use of a developing device which renders the process complex in steps and prolongs the time elapsing before the visible image is produced. Moreover, the images formed by this process are not fully satisfactory in quality.

Proposals have been made to use color developing recording sheets, such as the one described in Japanese Patent Publication No. 2234l/63., which depends for their operation on the action of an electric current passed thereto. This type of recording sheets generally comprise a coloration material layer 3 disposed on a conductive material layer 2 which is provided on an insulating supporter l as shown in FIG. I. In recording an information on this type of sheets, an electrode 5 connected to one terminal of a power source 4 is maintained in contact with the conductive material layer, and a recording electrode 5 connected to the other terminal of the power source 4 is used to scan the coloration material layer 3 so as to impress a voltage on the layer 3 while controlling the passing of a current thereto by signals obtained from a fixed graphic material.

As can be seen in FIG. 1, the voltage applied to the coloration material layer 3 is oriented perpendicularly to the longitudinal surface of the coloration material layer 3. It is believed that the operation of the layer 3 to color depends on a combination of effects including oxidation and reduction caused by the movement of electrons and ions made upon the impression of voltage, the heating effect of a current or Joules heat, and the impact of thermionic emission of electrons on the color developing material layer. It is necessary to reduce the resistance offered by the layer 3 in order to obtain an image of high quality. The high resistance offered by the coloration material layer 3 to the passing of a current would interfere with the mobility of ions and electrons and the generation of Joules heat, thereby reducing the density of the color developed. When a stylus electrode is employed as a recording electrode, an image produced may be cut off in several parts and lack continuity due to high resistance.

The need to reduce the resistance of the coloration material layer has hitherto placed limits on the materials used as coloration agents and binders. This has resulted in increased cost and a narrow range of colors to choose from.

SUMMARY OF THE INVENTION This invention obviates the aforementioned disadvantages of the conventional recording sheets whose operation depends on the action of a current passed thereto. Accordingly, the invention has as its object the provision of a novel electrical coloration recording sheet comprising an electrically conductive material layer of small thickness provided on a coloration material layer which is discolored or which colors upon impression of a voltage thereon.

1n the electrical coloration recording sheet according to the invention, the voltage applied thereto is not oriented perpendicularly to be longitudinal surface of the sheet as has hitherto been the case with a similar type of conventional recording sheets, but is oriented along the plane of the longitudinal surface because the coloration material layer of the recording sheet is coated with a conductive material layer of small thickness. The operation of the coloration recording sheet according to the invention depends primarily on the heating effect produced by the resistance of the conductive material layer to the recording electrode brought into contact therewith and the impact of thermionic emission of electrons from the recording electrode on the coloration material layer. A reduction phenomenon caused to take place in the color developing material layer by the thermoelectrons breaking through the conductive material layer and impinging on the coloration material may also be a contributing factor. It is intereiting to note that the electrical coloration material layer is heated almost to its melting point by a relatively low voltage to which it is exposed. Portions of the conductive material layer are removed by melting or evaporation and perform a sort of catalytic action in coloring or discoloring the coloration material layer.

The most important feature of this invention is that any coloration material may be used regardless of its resistance value, so that a composition for forming the coloration material layer may be selected from an almost infinite range of compositions. Thus, it is possible to select and use any material which colors most satisfactorily and to select any color that is to be developed. Besides, the use of the electrical coloration sheet according to the invention offers the additional advantage of permitting the electrode to be handled readily in operation.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 schematically shows a conventional recording sheet depending for its operation on the action of a current and means used for recording information thereon; and

FIG. 2 schematically shows an electrical coloration recording sheet according to the invention and means used for recording information thereon.

DESCRIPTION OF A PREFERRED EMBODIMENT The composition of the materials used for producing an electrical coloration sheet according to the invention and the production process thereof will now be described.

As shown in FIG. 2, the electrical coloration recording sheet comprises a supporter ll, a coloration material layer 12 disposed on the supporter 11 and a thin conductive material layer 13 disposed on the coloration material layer 12.

Any material selected from the group consisting of a plastic in sheet form, glass in sheet form, cloth, paper, synthetic paper and tracing paper, can be used as a supporter l 1.

The coloration material making up the layer 12 may be a mixture of a coloration material or materials selected from the materials of group (I) and a binder or binders selected from the materials of group (ll), and such mixture preferably comprise a coloration material or materials and a binder or binders in a range of ratios by weight of 20 to l to l to 2. The mixture is kneaded as by a ball mill and applied as by a wire bar to the surface of the supporter 11 to form a layer ranging in thickness from 1 to 100p. It is to be understood that the coloration material layer l2 may be formed by vacuum evaporation of a material or materials or group (I) alone on the supporter 11.

1. Electrical coloration material:

a. Samples of metal sulfides:

ZnS, Sb,S,, ln,S;,, and the like.

b. Samples of metal oxides:

Rb 0., Cs,0;,, ZnO, Cd,O HgO, GaO, Ga lnO, TiO,SnO,, Pb O 3, V 0 Nb,0 Ta,0,,, Shop, sbgog, C110 CrO M003, W203, T60 Teoa, Mnog, R6207, RUG 0S0, C0203, C030, and the like.

c. Samples of metallic acids:

HSbO HVO Hgseog, HgTiOa, Hzsnoa, H 860 HgMOO H WO HQUO4, Hasboa, H3Sb0 H4110, HgMOOa, H Sb H TaO H5Sb05, HgTeos, H SnO Hgpbo H [SiMo O, 30 H O,

H [PMo, 0.,,,] 30 H O,

H [PW, 0 30 H 0, and the like.

d. Samples of salts of metallic acids:

The salts of the metallic acids described in (c), for

example:

K Mo0 Na Mo0 (NH4 )2M004,

( fiel v ul 4 2 e. Another metallic compounds:

CuSCN, PbSCN, and the like.

f. Therrnochemical coloration material:

Zinc stearate Diphenylcarbazol,

Iron stearate l-formyl-4-phenylsemicarbazido,

and the like.

Materials of this subgroup color by forming, e.g.,

chelate compounds by the heating effect of a current.

ll. Binders:

a. Samples of oil soluble resins:

Pliolite S -5B Styrene butadiene copolymer made by Goodyear Tire and Rubber Co.

Pliolite S 7 Same to above.

Nylon resins Styrene-methyl methacrylate Butyl acrylate Acryl resin Polyvinyl pyrrolidone Polyvinyl acetate and the like.

b. Samples of water soluble resins:

Polyvinyl alcohol (P. V. Ac.) Made by Dow Chemical Co.

Conductive polymer 261 Made by Calgon Co.

and the like.

c. Another binders:

Gelatine, Starch paste, and the like.

The thin conductive material layer 13 provided on the coloration material layer 12 may be formed by either vacuum evaporization or sputtering method on the layer 12 of a material or materials listed below or applying to its surface a mixture of a material or materials listed below with a binder material or materials listed in group (ll) above. The surface resistance of the coloration material layer 13 is set at less than 10 (0), or preferably in a range from 10 to 10 (Q). (lll) Thin conductive material layer forming materials:

a. Metals:

Fe, Co, Ni, Al, Cu, Au, Ag, Zn, Ti, In, and the like.

b. Metallic compounds:

1n,o,, SnO Cul, CuBr CuBr, Pbo,, FeS,,

and the like.

In' recording an image of an original by using information signals acting on electrical coloration recording sheet made from the various materials listed above, an electrode 15 connected to one terminal of a power source 14 is brought into contact with one comer of the thin conductive material layer 13, and a recording electrode 16 connected to the other terminal of the power source 14 is used to scan the thin conductive layer 13 so as to form an image from information on the sheet by controlling the passing of a current to the sheet by information signals.

CaMolL, PbMo0 More specifically, if a voltage is impressed on the thin conductive material layer 13 through the recording electrode 16 by an information signal, a current will flow in the thin conductive material layer 13 from the point of contact between the recording electrode l6 and layer 13 to the electrode 15. The resistance offered by the point of contact on the layer 13 is what is referred to as a contact resistance and a very high in value, so that the heat generated at the point of contact is sufficiently high to cause the corresponding portion of the coloration material layer 12 to color. At the same time, thermoelectrons are produced by the recording electrode 16 and supplied to the thin conductive material layer 13, with some of them breaking through layer 13 and invading layer 12 to cause reduction to take place on layer 12. Thus, portions of the conductive material layer 13 on which the voltage is impressed by contact with the recording electrode 16 are removed by either melting or evaporation due to the heat generated therein and perform a sort of catalytic action in a thermal coloring reaction. Thus, a recorded likeness of the original is produced on the sheet by scanning the surface of the thin conductive material layer 13 while controlling the passing of the current from the fonner to the latter by information signals. The recorded image is very clear, well defined and high in density.

Example 1 A mixture of parts of H,Mo0,. 2l-l,0, 2 parts of Pliolite S-7 (trade name) and 30 parts of toluene (the parts are all by weight) was placed in a ball mill and kneaded for fifteen minutes. Then, the mixture was applied by a wire bar to the surface of a sheet of commercially available tracing paper to form a layer thereof of about 5;]. in thickness, and dried for half an hour by exposing the layer to dry air of 100C.

An electrically conductive material layer was formed, on the electrical coloration layer formed as aforementioned, by vacuum evaporation of aluminum thereon under the pressure of l0' mmHg. The conductive material layer formed had a surface resistance of 10 0. The electrical coloration developing recording sheet produced in this way was tested by scanning its surface with Toshafax made by Tokyo Aircraft Meters Company and passing thereto an alternating current of about 100 volts to the conductive material layer. A clear black positive image of the original was produced.

Example 2 A mixture of 10 parts of ZnO, 2 parts of P.V.Ac. and 30 parts of methanol (the parts are all by weight) was placed in a ball mill and kneaded for four hours. Then, the mixture was applied by a wire bar to the surface of a sheet of commercially available high quality paper to form a layer thereof of about lOp. in thickness, and dried for half an hour at 100C.

An electrically conductive material layer was formed, on the electrical coloration material layer formed as aforementioned, by vacuum evaporation of aluminum thereon under the pressure of 10mml-lg. The conductive material layer has a surface resistance of 10 .0. The electrical coloration recording sheet produced in this way was tested by scanning its surface with the Toshafax referred to in Example 1 and passing thereto a direct current of about +75 volts. A dark brown positive image of the original was produced.

Example 3 A mixture of 10 parts of V 0 3 parts of RP 505 (made by Monsanto Company), 5 parts of water and 25 parts of CH OH (the parts are all by weight) was placed in a ball mill and kneaded for 8 hours. Then, the mixture was applied by a wire bar to the surface of a sheet of a commercially available high quality paper to form a layer thereof of about 5p. in thickness, and dried for half an hour by exposing the layer to dry air of 100C.

An electrically conductive material layer was formed, on the electrical coloration material layer formed as aforementioned, by vacuum evaporation of aluminum thereon under the pressure of l0"'mml-lg. The conductive material layer formed had a surface resistance of 10 0. The electrical coloration recording sheet produced in this way was tested by scanning its surface with the aforementioned Toshafax and passing thereto a direct current of +1000 volts to the photoconductive material layer. A clear pure black positive image of the original was produced.

Example 4 A mixture (1) of 1 part of zinc stearate, 5 parts of P.V.Ac. and 20 parts of methanol (all the parts are by weight) and a mixture (2) of 1 part of diphenylcarbazone, 10 parts of P.V.Ac. and 20 parts of methanol (all the parts are by weight) were placed in separate ball mills and kneaded for 4 hours. Then, the mixtures (l) and (2) were mixed together and applied by a wire bar to the surface of a commercially available polyester film to form a layer thereof of about 10 pin thickness, and dried for half an hour at C.

An electrically conductive material layer was formed, on the electrical coloration material layer formed as aforementioned, by vacuum evaporation of indium thereon under the pressure of 10'' mmHg. The thin conductive material layer thus formed had a surface resistance of 5 X 10 0. When it was tested by scanning its surface with the aforementioned Toshafax and passing thereto a direct current of +500 volts, a beautiful positive image was produced.

Example 5 A mixture of 5 parts of ZnO, 5 parts of ln,O 2 parts of P.V.Ac. and 30 parts of CH -,Ol-l (all the parts are by weight) was placed in a ball mill and kneaded for 8 hours. Then, the mixture was applied by a wire bar to the surface of a sheet of commercially available tracing paper to form a layer thereof of Spin thickness, and dried for 50 minutes in dry air at l00C.

A transparent Cul film of several 0 was formed, on the surface of the electrical coloration material layer thus formed, by vacuum evaporation of copper under the pressure of l0 mmHg and then by exposing the deposited material to iodine in vapor form. The thin conductive material layer or Cul film formed in this way had a surface resistance of 10 0. Tests performed by scanning the surface of the electrical coloration recording sheet with the aforementioned Toshafax and passing thereto a direct current of +300 volts showed that the sheet was capable of producing a dark brown clear positive image thereon.

Example 6 A mixture of 10 parts of (NH ),Mo O24.4H O 2 parts of crotonic acid acrylic acid ester copolymer and 30 parts of methanol was placed in a ball mill and kneaded for 10 hours. Then, the mixture was applied by a wire bar to the surface of a sheet of commercially available tracing paper to form a layer thereof of about 5 in thickness, and dried for 30 minutes in dry air at 100C.

An electrically conductive material layer was formed, on the surface of the electrical coloration material layer formed in this way, by vacuum evaporation of indium under the pressure of l""mml-lg, so that the conductive material layer formed had a surface resistance of about lOOOfl. Tests conducted by scanning the surface of the electrical coloration recording sheet to carry out recording of information showed that a clear black positive image was produced.

Example 7 A electrically conductive material layer was formed on the surface of the electrical coloration material layer formed by the same way described in Example 6, by spattering method of SnO under the pressure of l0mmHg in 95% Argon- Oxygen mixed gas. The electrically conductive material layer had a surface resistance of about 10 K0,.

As the result of the same tests as described in Example 6, a clear black positive image was produced.

What is claimed is:

1. An electrical coloration recording sheet comprising an electrical coloration material layer and a thin electrically conductive material layer formed on said electrical coloration material layer, said electrical coloration material layer made of a material which changes color but is not destroyed at a point adjacent a point of the thin electrically conductive material layer to which a selected electrical signal is applied with a re cording electrode whereby a recorded likeness of an original may be produced on said sheet by selected electric signals.

2. An electrical coloration recording sheet according to claim 1 wherein said electrical coloration material layer is formed of at least one of metallic sulfides, metallic oxides, metallic acids, metallic acid salts, other metallic compounds and thermic coloration materials.

3. An electrical coloration recording sheet according to claim 1 wherein said electrical coloration material layer is composed of an electrical coloration material or materials and a binder or binders.

4. An electrical coloration recording sheet according to claim 1 wherein said electrical coloration material or materials comprise at least one of metallic sulfides, metallic oxides, metallic acids, metallic acid salts, other metallic compounds and thermic coloration materials.

5. An electrical coloration recording sheet according to claim 3 wherein said binder or binders comprise at least one of oil-soluble resins, water-soluble resins and other binder materials.

6. An electrical coloration recording sheet according to claim 1 wherein said thin electrically conductive material layer comprises at least one of metals and metallic compounds.

7. An electrical coloration recording sheet according to claim 1 wherein said thin electrically conductive material layer is composed of a thin electrically conductive material layer forming material and at least one binder.

8. An electrical coloration recording sheet according to claim 7 wherein said thin electrically conductive material layer forming material comprises of at least one of metals and metallic compounds.

9. An electrical coloration recording sheet according to claim 7 wherein said at least one binder material comprises at least one of oil-soluble resins, watersoluble resins and other binder materials.

10. An electrical coloration recording sheet according to claim 1 wherein said electrical coloration material layer is formed by vacuum evaporation or application.

11. An electrical coloration recording sheet according to claim 1 wherein said thin electrically conductive material layer is formed by vacuum evaporation, spattering or application.

12. An electrical coloration recording sheet comprising an electrical coloration material layer and an electrically conductive material layer, one flat side of the conductive layer being disposed on the coloration layer and the other flat side of the conductive layer being exposed, said coloration layer being made of a material which changes color locally in response to the application of a selected electrical signal to an adjacent point on the exposed side of the conductive layer, said coloration layer remaining continuous after local color changes thereof.

13. A recording sheet as in claim 12 wherein the conductive layer is made of a material which destructs locally in response to the application of said electrical signal to a point thereof.

14. A recording sheet as in claim 12 wherein the col oration layer includes a material selected from the group consisting of metallic sulfides, metallic oxides, metallic acids, metallic acid salts, and further includes a binder selected from the group consisting of oilsoluble resins and water-soluble resins.

15. A method of forming an image on an electrical coloration recording sheet comprising an electric coloration material layer and an electrically conductive material layer having one side disposed on the coloration layer and the other side exposed, said method comprising the steps of:

providing a first electrode and a recording electrode;

establishing electrical contact between the exposed side of the conductive layer and the first electrode and a potential difference between the first and the recording electrode; and

contacting selected points on the exposed side of the conductive layer with the recording electrode to cause corresponding points of the coloration layer to change color without destruction of the points of the coloration layer which have changed color.

16. A method as in claim 15 wherein the step of contacting selected points of the conductive layer with the recording electrode includes destruction of said points of the conductive layer without destruction of the adjacent points of the coloration layer. ll l i

Claims

1. AN ELECTRICAL COLORATION RECORDING SHEET COMPRISING AN ELECTRICAL COLORATION MATERIAL LAYER AND A THIN ELECTRICALLY CONDUCTIVE MATERIAL LAYER FORMED ON SAID ELECTRICAL COLORATION MATERIAL LAYER, SAID ELECTRICAL COLORATION MATERIAL LAYER MADE OF A MATERIAL WHICH CHANGES COLOR BUT IS NOT DESTROYED AT A POINT ADJACENT A POINT OF THE THIN ELECTRICALLY CONDUCTIVE MATERIAL LAYER TO WHICH A SELECTED ELECTRICAL SIGNAL IS APPLIED WITH

9. An electrical coloration recording sheet according to claim 7 wherein said at least one binder material comprises at least one of oil-soluble resins, water-soluble resins and other binder materials.

14. A recording sheet as in claim 12 wherein the coloration layer includes a material selected from the group consisting of metallic sulfides, metallic oxides, metallic acids, metallic acid salts, and further includes a binder selected from the group consisting of oil-soluble resins and water-soluble resins.

15. A method of forming an image on an electrical coloration recording sheet comprising an electric coloration material layer and an electrically conductive material layer having one side disposed on the coloration layer and the other side exposed, said method comprising the steps of: providing a first electrode and a recording electrode; establishing electrical contact between the exposed side of the conductive layer and the first electrode and a potential difference between the first and the recording electrode; and contacting selected points on the exposed side of the conductive layer with the recording electrode to cause corresponding points of the coloration layer to change color without destruction of the points of the coloration layer which have changed color.

16. A method as in claim 15 wherein the step of contacting selected points of the conductive layer with the recording electrode includes destruction of said points of The conductive layer without destruction of the adjacent points of the coloration layer.