US3898672A - Electrosensitive recording member - Google Patents

Abstract

Electrosensitive recording member in which blackish pattern is electrically formed on a recording layer by sparking between a needle-like electrode (stylus) and the recording layer comprising a binder and an electrically reducible metal compound. Copper iodide (CuI) is specifically included in the recording layer to increase its electroconductivity.

Description

United States Patent Yasumori et al.

Related US. Application Data Continuation of Ser. No. 324,829, Jan. 18, 1973, abandoned.

Foreign Application Priority Data Jan, 28, 1972 Japan 47-10897 [.S. Cl. 346/135; 117/201', 204/2;

Int. Cl. G0ld 15/34 Field of Search... 346/135, 74 S, 74 SB, 74 SC; 117/201, 221', 204/2; 252/507, 518, 520

Aug. 5, 1975 [561 References Cited UNITED STATES PATENTS 2,294,149 8/1942 Kline et al. 346/135 2,940,941 6/1960 Dalton 252/520 X 3,138,547 6/1964 Clark 204/2 3,245,833 4/1966 Trevoy...v 117/201 3,263,604 8/1966 Dalton.... 346/135 X 3,516,911 6/1970 Hopps 204/2 3,684,746 8/1972 .luna et al. 252/507 Primary Examiner.loseph W. Hartary Attorney, Agent, or FirmCooper, Dunham, Clark, Griffin & Moran [57] ABSTRACT Electrosensitive recording member in which blackish pattern is electrically formed on a recording layer by sparking between a needle-like electrode (stylus) and the recording layer comprising a binder and an electrically reducible metal compound. Copper iodide (Cul) is specifically included in the recording layer to increase its electroconductivity.

6 Claims, 3 Drawing Figures ELECTROSENSITIVE RECORDING MEMBER This is a continuation of application Ser. No. 324,82) filed Jan. 18. 1973. now abandoned.

BACKGROUND OF THE INVENTION Dry recording members are well known. They are prepared by applying an electrically destructive substance on anelectroconductivc support having an electroconductivc layer such as carbon. The electrically destructive substance is. for example, a synthetic resin. In the dry recording members the elcetroconductive layer functions as one electrode, and the other electrode is a metallic needle-like electrode (stylus) which contacts the layer of electrically destructive substance. By applying a DC. or AC. voltage, for example 100 4 150V, between the two electrodes separated by the destructive substance layer, an electric current mA) flows and consequently the destructive layer is broken down and the carbon black layer appears. The needlelike electrode (stylus) is moved while contacting the electrically destructive layer. The pattern of the carbon black is formed on the support by controlled tracing of the stylus. The dry recording member is used in the field of a facsimile recording. However, dry recording members have several shortcomings. For example, l) they may not be suffieiently sensitive; (2) when the voltage is applied, an offensive odor is emitted as a result of the combustion of the electrically destructive substance; (3) they may be undesirable sparking and breakdown of the recording member caused by in-- creasing the voltage in order to speed up the recording.

Substitutes for the above described dry recording members have been proposed and disclosed, for exam ple, in U.S. Pat} Nos. 3,138,547 and No. 3,516,911. In

the proposed substitutes, the electrosensitive recording members consist essentially of a recording layer formed on an elcetroconductive support. The recording layer comprises a mixture of powder of an electrically reducible metal compound such as ZnO, SnO TiO Bi- O V 0 Sta- S or H MoO and a synthetic resin binder such as synthetic rubber or ethyl cellulose. The electroconductive support is, for example, a metallic foil or an elcetroconductive plastic film. These electrosensitive recording members may be used in the same manner as the described dry recording members. A blackish pattern is formed on the recording layer by tracing of the stylus.

An object of the present invention is to provide improved electrosensitive recording members. The recording members of the present invention are characterized by the low resistance of the recording layer. Therefore, a nonconductive support may be utilized and consequently, the recording member can be provided inexpensively. Further, vivid black patterns of high density can be formed on the recording layer.

SUMMARY OF THE INVENTION metal compound and copper iodide (Cul Cu] is an electroconductivity-increasing substance. The metal compound and Cul are uniformly dispersed in the binder. As a result. the electrosensitive recording membcrs of the invention all have an electrosensitive recording layer with a high electroconductivity. Accordingly. the electrosensitive recording members of this invention are characterized in that: (l a nonconductive support may be utilized (the use of an electroconductive support is not necessarily required), and (2) a vivid pattern ofhigh density can be formed on the electrosensitive recording layer at high recording speed by applying a relatively low voltage. A nonconductive support such as paper or plastic film is inexpensive in comparison with an elcetroconductive support such as aluminum foil or aluminum-coated paper. This is a feature of the present invention. However, an electrosensitive recording layer containing Cul in accordance with this invention may be formed on the elcetroconductive support. v

The electrically reducible metal compounds which may be used in forming an electrosensitive recording layer of the invention are as follows: zinc oxide (ZnO), cadmium oxide (CdO), barium oxide (BaO), tin oxide (SnO lead oxide (PbO, Pb O PbO titanium oxide (TiO zirconium oxide (ZrO antimony oxide (Sb O Sb O Pb O bismuth oxide (Bi O Bi O Bi O vanadium oxide (V 0 molybdenum oxide (M00 tungsten oxide (W0 cerium oxide (CeO molybclic acid (H MoO tungstic acid (H WO molybdates (Na MoO K MQO}, CaMoO PbMoO (NH )5MO7O24-4H2O, Na' Mo o l 7- H O, (NH [CrMo O ].2H O), molybdosilicic acid (H ,[SiO Mo 05, 1), molybdophosphoric acid (H PO Mo, O; ),'tungstophosphoric acid (H PO W- 0 1), cobalt oxides C0 03. C0 0 mercury oxide (HgO), chromium oxide (C50 niobium oxide (Nb O tantalum oxide (T112055), manganese oxide (MnO antimonic acid (HSbO H SbO stannic acid (SnO .xl-I O), titanic acid (H TiO H TiO vanadic acid (HVO selenic acid (H SeO bismuthate (NaBiO zinc sulfide (ZnS) and antimony sulfide 2 s)- I Among the above-cited metal compounds, ZnO, TiO V 0 H MoO H WO and (NE Mo O 4H O are preferred. i I

The following organic compounds may preferably be used as a nonconductive binder: polyvinyl alcohol, polyvinyl acetate, polyvinyl chloride, ethyl cellulose, gelatin, butadiene-styrene copolymers, vinyl acetateerotonic acid copolymers, polymethylmethacrylate, polyethylmethacrylate and the like.

Preferred solvents for use in dissolving the binder are as follows: water, ammonia water, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, eyclohexane, alcohols such as methyl alcohol and ethyl alcohol, aliphatic hydrocarbon such as petroleum solvents and isoparaffinic solvents.

Paper or plastic films are the preferred nonconductive supports. However, electroconductive supports,

' for example, metal-coated sheets such as aluminumreducible metal compound. However, the amount of Cul used may be up to 30 parts by weight perone part by weight of the metal compound.

Certain embodiments of the invention are illustrated in the accompanying drawings in which:

FIG. 1 is a cross section of one form of the invention using a paper as a nonconductive support.

FIG. 2 is a cross section of a modification of the invention using a metal-coated paper as an electroconductive support.

FIG. 3 shows the method of recording on an electrosensitive recording layer prepared in accordance with the invention.

The FIGURES show the thickness of the paper and the coating layer thereon enlarged as compared with their actual thickness, for the sake of clarity of illustration.

binder selected from amongst the above-cited organic binders is dissolved in a solvent and to this solution is added at least one of the electrically reducible metal compounds and Cul in the above-mentioned ratio. The resulting mixture is dispersed or suspended by ball milling to produce a homogeneousdispersion of the metal compound and Cul in a solution of the binder. The resulting dispersion is applied onto a surface of paper 1 by means of e.g. a wire-bar and then dried at a temperature of about 100C to form an electrosensitive recording layer 2 on the surface of the paper 1. The preferred thickness of the recording layer is from about to about 100 1.. Alternatively, as shown FIG. 2, an electrosensitive recording layer 2 may be formed on a metal-coating 3 of a metal-coated paper 1.

Referring to FIG. 3, the electrosensitive recording member thus obtained is placed on a flat plate 4 and a DC. or an A.C.-voltage of from 50 to 200V is applied to a stylus 5 and a lead wire 6 and the stylus is traced at a speed of from 400 m/min. in light contact with the recording layer 2. A current of from 5 to 200 mAmp. flows between the stylus 5 and the recording layer 2 and the passage of the current causes the metal A compound to become reduced to a dark compound in color contrast with the surrounding unreduced portions of the electrosensitive recording layer. A vivid blackish pattern is formed according to the tracings of the stylus.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The following nonlimiting examples are given by way of illustration only.

EXAMPLE 1 A dispersion for use in forming an electrosensitive recording layer was prepared from the following ingreclients:

H MuO 20g C ul lOUg Butadienestyrene 15g copolymer Toluene ml Butadiene-styrene copolymer was dissoved in toluene, and to this solution was added H MoO and Cul. This mixture was dispersed by ball milling for about 24 hours. The homogeneous dispersion thus produced was applied ontoa surface of paper by means of a wire-bar and then dried at a temperature of about 100C to obtain an electrosensitive recording member with a light yellowish recording layer 10 p. thick. The sheet resistance of this recording layer was lO fl/square. Utilizing the electrosensitive recording member thus prepared, a pattern was produced, in the manner as shown in FIG. 3, under the following conditions:

Recording device used Applied voltage Moving speed of stylus A vivid greenish black pattern having a density of l .3 was produced on the recording layer. The density was measured by means of Macbeth Densitometer RD- 400 sold by Macbeth Institute.

For comparison, a control electrosensitive recording member was prepared by the same procedure except that g of H MoO was used in place of 20g of H MoO and 100g of Cul. The sheet resistance of the recording layer thus produced was about 10 Q/square. The same procedure mentioned above was repeated to form a pattern except that a DC. voltage of 200V was applied instead of 100V. However, no pattern could be produced.

Another control electrosensitive recording member containing Cul was prepared by the above procedure except that aluminum-coated paper was utilized as a support in place of paper. The recording member thus prepared gave a blackish pattern having a density of 1.0 at a DC. voltage of 80V and stylus speed of m/min. It is apparent from this example that the products of this invention can give a vivid pattern even when the stylus is moved at a relatively high moving speed.

EXAMPLE 2 EXAMPLE l0 Electrosensitivc recording members No. 2 No. 10 were-prepared by repeating the procedure of Example 1 except that metal compounds, binders and solvents shown in the table below were used. In these Examples,

paper was used as a support.

A pattern was produced on each of the recording members No. 2 No. 10 in the same manner as Example l. and the pattern thus obtained was evaluated. The data and the results are shown in the table below:

copolymer 5 Table Continued Example Metal Cul Binder Solvent Applied Pattern Compound voltage No (g) (g) (g) (ml) (V) Color Density 4 K MoO Butadiene- Toluene D.C. Greenish Styrene Brown 0.8 20 I00 copolymer 100 200 5 H WO Vinyl Methyl D.C.

acetatealcohol Black 1 .0 20 crotonic 50 100 acid copolymcr 5 6 (NH Vinyl Methyl D.C.

acetatealcohol Black 1 .0 M0 0 20 crotonic 50 I00 4H O acid copolymer 20 5 7 V 0 Polyvinyl Water D.C.

alcohol Black 1 .3 20 5 50 100 8 ZnO Vinyl Methyl D.C. Brownish acetatealcohol black 08 20 40 crotonic 70 I00 acid copolymer l0 9 ZnO Butadiene- Toluene D.C.

I0 40 styrene 70 100 Black l .0 H MoO copolymer l0 l0 l0 TiO Butadiene- Toluene D.C. Bluish l 0 styrene black 0.7

40 copolymer 70 100 (NH4)I| 1 24 4H O 10 As is seen from the above-mentioned data, preferred electrosensitive recording members can be obtained by forming an electrosensitive recording layer containing C ul in an amount of from 1 to 10 parts by weight of C Ul per one part by weight of an electrically reducible metal compound on a nonconductive support. When said electrosensitive recording layer containing Cul is formed on an electroconductive support such as aluminum foil or aluminum-coated paper, a good pattern of high density can be produced at relatively low voltage even when the stylus is moved.

We claim:

1. Ah eleetkosefisi'tive recording member comprising a neneonduetive support and an electrosensitive recording layer formed on the support, said electrosensitive meet-ding layer containing a binder having a mixture oi an electrically reducible metal compound and copper iodide (Cul) dispersed therein; the weight ratio of mixture to hinder being from 5:1 to 10:1.

2. An electrosensitive recording member of claim 1 in which said mixture of an electrically reducible metal compound and copper iodide is a mixture of one part by weight of the electrically reducible metal compound and from I to 10 parts by weight of copper iodide.

3. An electrosensitive recording member of claim 1 in which said electrically reducible metal compound is one selected from the group consisting of ZnO, TiO V 0 H MoO H WO and (NH Mo,O .4H O.

4. An electrosensitive recording member of claim 1 wherein the nonconductive support is paper.

5. An electrosensitive recording member of claim 1 whercin the nonconductive support is a plastic.

6. An electrosensitive recording member of claim 1 in which said mixture of an electrically reducible metal compound in copper iodide is a mixture of 1 part by weight of the electrically reducible metal compound and from 1 to 10 parts by weight of copper iodide.

Claims (6)

1. AN ELECTROSENSITIVE RECORDING MEMBER COMPRISING A NONCONDUCTIVE SUPPORT AND AN ELECTROSENSITIVE RECORDEING LAYER FORMED ON THE SUPPORT, SAID ELECTROSENSITIVE RECORDING LAYER CONTAINING A BINDER HAVING A MIXTURE OF AN ELECTRICALLY REDUCIBLE METAL COMPOUND AND COPPER IODIDE (CUL) DDISPERSED THEREIN, THE WEIGHT RATIO OF MIXTURE TO BINDER BEING FROM 5:1 TO 10:1.

2. An electrosensitive recording member of claim 1 in which said mixture of an electrically reducible metal compound and copper iodide is a mixture of one part by weight of the electrically reducible metal compound and from 1 to 10 parts by weight of copper iodide.

3. An electrosensitive recording member of claim 1 in which said electrically reducible metal compound is one selected from the group consisting of ZnO, TiO2, V2O5, H2MoO4, H2WO4 and (NH4)6Mo7O24.4H2O.

4. An electrosensitive recording member of claim 1 wherein the nonconductive support is paper.

5. An electrosensitive recording member of claim 1 wherein the nonconductive support is a plastic.

6. An electrosensitive recording member of claim 1 in which said mixture of an electrically reducible metal compound in copper iodide is a mixture of 1 part by weight of the electrically reducible metal compound and from 1 to 10 parts by weight of copper iodide.

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