JPH0560857B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an electrostatic recording sheet, and in particular to a sheet that is directly printed by an electrostatic plotter used in a CAD (Computer Aided Design) system. The present invention relates to an electrostatic recording sheet that can perform various functions.

(Prior Art) It has been known that toner fogging, called lead edge fogging or background, occurs during recording in electrostatic recording sheets using insulating supports. To solve this problem, the following methods have been proposed so far.

a) A method of removing fog by insulating the developing section of an electrostatic plotter.

b) By exposing a part of the conductive layer of the recording medium, and while the recording medium is moving and recording, this exposed conductive layer contacts the paper feed roll, guide roll, developing section, etc. and is grounded. How to remove fog.

c) After cutting the recording medium to a predetermined width, apply conductive paint to both edges of the surface of the dielectric layer so as to connect it to the conductive layer at the end surface, and as in b, while the recording medium is moving, A method of removing fog by touching a part of the plotter and grounding it.

d) A method of eliminating fog by providing a through hole in the support and filling the through hole with a conductive agent so that the conductive layer is grounded through the back surface of the recording medium.

However, among these methods, a) not only requires the plotter itself to have the above-mentioned functions, but also reduces the recording density, and b) and c) are not suitable for mass supply of products with different recording widths. In addition, there are problems in d), such as the difficulty in supplying technically stable and inexpensive products, and these problems have not been sufficiently solved to date.

(Problems to be Solved by the Invention) The present invention aims to eliminate the above-mentioned drawbacks and to stably and easily supply an electrostatic recording sheet having good recording quality without fogging during recording. .

(Means for Solving the Problems) As a result of research, the present inventors found that in an electrostatic recording sheet in which a conductive layer and a dielectric layer are laminated in this order on an insulating support, there is an electrical resistance at both ends of the surface of the dielectric layer. 1×
It has been found that by providing a conductive band having a conductivity of 10 ⁵ Ω/cm or less, it is possible to prevent fogging during recording. When recording with this electrostatic recording sheet, the conductive band portion provided on the surface of the induction layer is connected to a paper feed roll, a guide roll,
By bringing the developing section into contact with the grounded plotter main body, fogging can be effectively prevented.

1 and 2 are conceptual diagrams showing the structure of the electrostatic recording sheet of the present invention, where A is an insulating support and B is a conceptual diagram showing the structure of an electrostatic recording sheet of the present invention.
indicates a conductive layer, and C indicates a dielectric layer. Conductive bands D are provided continuously on both ends of the surface of the dielectric layer C. This conductive band is considered to be capacitively coupled to the conductive layer B. The conductive band has an electrical resistance value of 1×10 ⁵
Must be less than Ω/cm. If the coating exhibits an electrical resistance value exceeding 1×10 ⁺ Ω/cm after drying, fogging during recording cannot be completely prevented. In order to keep the electrical resistance value below 1×10 ⁵ Ω/cm, the conductive band is made by using carbon black, fine metal powder such as silver, copper, aluminum, zinc, etc. in combination with an appropriate adhesive. Form. In addition to this, the conductive agent can be selected so that the electrical resistance value is 1×10 ⁵ Ω/cm or less. As the adhesive for forming the conductive band, a non-hygroscopic hydrophobic adhesive is more effective because it has less humidity change in resistance value, and commonly known polymer adhesives such as vinyl acetate, vinyl chloride, Polymers or copolymers of styrene, butadiene, acrylic esters, methacrylic esters, ethylene, acrylonitrile, etc., silicone resins, polyester resins, polyurethane resins, alkyd resins, epoxy resins, etc.
A species or two or more species may be used as appropriate. The conductive band generally has a width of 0.5 mm to 5 mm, and preferably has a width of 1 mm to 4 mm.

In the electrostatic recording sheet of the present invention, the support is an organic polymer film, ie, polyester,
In addition to polyolefin, polystyrene, polyvinyl chloride, polycarbonate, etc., synthetic paper and polyethylene laminated paper can also be used.

In addition, if a transparent or semi-transparent support is used as a conductive agent, a transparent ion conductive type conductive agent can be used as a conductive agent.
Although it is possible to obtain an electrostatic recording sheet that is capable of diazo copying, the recording quality is affected by the environment. On the other hand, by using an electron-conducting conductive agent with an average particle size of 1 μm or less and a cross-linked curing organic polymer binder, it is possible to obtain an electrostatic recording sheet that is less susceptible to environmental influences and is capable of diazocopying.

A conductive layer is formed on the support. Ion conductive conductive agents such as quaternary ammonium salts can also be used as conductive agents for forming conductive layers, but they have the disadvantage that the recording quality is easily affected by the environment, and electron conductive conductive agents can be used. A combination of the agent and a hydrophobic organic polymer material, particularly a crosslinked polymer material that becomes insoluble or poorly soluble in organic solvents after curing, is preferred. Examples of the electron-conducting conductive agent include conductive mica, zinc oxide, tin oxide, indium oxide, titanium oxide, vanadium oxide, and fine metal powder. As an adhesive for forming a conductive layer,
Hydrophobic materials are preferred, such as commonly used polymers or copolymers such as vinyl acetate, vinyl chloride, styrene, butadiene, acrylic esters, methacrylic esters, ethylene, acrylonitrile, silicone resins, polyester resins, polyurethane resins, and alkyds. Resin, epoxy resin, etc. can be used. However, it is particularly desirable to use a crosslinkable polymer material that is not affected by the environment, has excellent solvent resistance, and does not change over time. Examples of crosslinkable polymer materials include crosslinked urethane resins, acrylic resins, acrylic ester resins, methacrylic ester resins, phenolic resins, melamine resins,
Amino resins such as urea resins, alkyd resins, epoxy resins, butyral resins, organosilicon compounds,
Examples include petroleum resins and unsaturated polyesters, and one or a combination of two or more of these can be used. After coating these compositions, they are crosslinked and cured by heat treatment, UV treatment, electron beam treatment, or by adding a crosslinking agent or additives, if necessary. It is also possible to use a combination of one or more of these crosslinkable resins and one or more of the usual hydrophobic binders listed above.

A dielectric layer is formed on the conductive layer. The dielectric layer forming material consists of a dielectric resin and an inorganic or organic pigment. Examples of the dielectric resin include polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyacrylic ester, polymethacrylic ester, polystyrene, butyral resin, silicone resin, epoxy resin, polyolefin, polyurethane, polyvinyl acetal, etc. alone or One or more copolymers can be used. As an inorganic pigment,
For example, kaolin, calcium carbonate, amorphous silica, aluminum hydroxide, etc. are used, and organic pigments include polyethylene powder, polystyrene powder,
Synthetic resin powder such as polyester powder can be used.

Examples Example 1 Ion-conducting conductive agent (Chemistat 6300, manufactured by Sanyo Chemical Industries, Ltd., solid content 33%) on one side of a 75 μm thick polyester film (Lumirror #15 manufactured by Toray Industries, Inc.)
A conductive layer was obtained by applying a coating solution consisting of 60 parts by weight and 40 parts by weight of water using a Meyer bar so that the coating amount after drying was 5.5 g/m ² . Next, on top of this conductive layer, a copolymer mainly composed of polyacrylic acid ester (Himer SBA720 manufactured by Sanyo Chemical Co., Ltd., solid content 45
A dielectric layer solution consisting of 60 parts by weight of calcium carbonate, 3 parts by weight of calcium carbonate, and 37 parts by weight of toluene was coated using a Mayer bar so that the coating amount after drying was 4.5 g/m ² . Then, on both ends of the surface of this dielectric layer, 60 parts by weight of carbon black, vinyl chloride/vinyl oxide copolymer (Sevian A manufactured by Daicel Corporation, solid content 40 parts by weight)
%) and 340 parts by weight of methyl ethyl ketone was applied to a thickness of 1 μm with a width of 2 mm to obtain an electrostatic recording sheet. The electrical resistance value of this conductive band is
Under conditions of 25℃/45%RH, 3×10 ⁴ Ω/
cm. As a result of printing this electrostatic recording sheet using an electrostatic plotter (Versatech 7424),
Good records with no fog were obtained under the conditions of 25°C/45% RH.

Example 2 On one side of 75 μm thick translucent synthetic paper (YUPO TPG-75 manufactured by Oji Yuka Synthetic Paper Co., Ltd.), particles with an average particle size of 0.1 μm were coated.
10 parts by weight of conductive tin oxide (manufactured by Mitsubishi Metals Co., Ltd., T-1), two-component urethane resin (manufactured by Nippon Polyurethane Co., Ltd., Nipporan 800/1000 = 1/1, solid content 40%)
8 parts by weight, isocyanate as a curing agent (manufactured by Nippon Polyurethane Co., Ltd., Coronate L, solid content 75%) 12
A coating liquid consisting of 40 parts by weight, 40 parts by weight of ethyl acetate, and 40 parts by weight of butyl acetate was applied using a Mayer bar so that the coating amount after drying was 1.5 g/m ^{2 .}
A conductive layer was obtained by leaving it in the sun. Next, a dielectric layer was coated on this conductive layer in the same manner as in Example 1, and 60 parts by weight of carbon black and polyester resin (Vylon manufactured by Toyobo Co., Ltd., solid content 30%) were coated on both ends of the surface of this dielectric layer. ) 140 parts by weight and 300 parts by weight of methyl ethyl ketone.
An electrostatic recording sheet was obtained by coating to a thickness of . The electrical resistance value of this conductive band is 8×10 ³ Ω/cm under the conditions of 25° C./45% RH. The results of printing this electrostatic recording sheet using an electrostatic printer (Versatech 7424) were as follows: 20℃/10%RH~20℃/85
Good records with no fog were obtained under a wide range of test environment conditions including %RH.

Comparative Example 1 A conductive layer was formed on one side of a 75 μm thick polyester film (Lumirror #75 manufactured by Toray Industries, Inc.) in the same manner as in Example 1. Next, a dielectric layer coating solution prepared in the same manner as in Example 1 was applied onto this conductive layer using a Mayer bar so that the coating amount after drying was 4.5 g/m ² . Example 1 was applied to both ends of the surface of the layer.
An electrostatic recording sheet was obtained by applying the same conductive band coating liquid to a thickness of 0.4 μm with a width of 2 mm. The electrical resistance value of this conductive band is under the conditions of 25℃/45%RH.
It is 5×10 ⁵ Ω/cm. This electrostatic recording sheet
As a result of printing using an electrostatic plotter (Versatech 7424), fogging occurred under conditions of 25° C./45 RH, and good recording could not be obtained.

Comparative Example 2 On one side of translucent synthetic paper (YUPO TPG-75),
A conductive layer was obtained in the same manner as in Example 2. Next, a dielectric layer is coated on this conductive layer in the same manner as in Example 1, and the same conductive band coating liquid as in Example 2 is applied to both ends of the surface of this dielectric layer with a width of 0.3 mm. It was coated to a thickness of μm to obtain an electrostatic recording sheet capable of diazocopy. The electrical resistance value of this conductive band is 25℃/45
Under the condition of %RH, it is 1×10 ⁶ Ω/cm.
This electrostatic recording sheet was printed using an electrostatic plotter (Versatech 7424), and the result was 20℃/10%.
Fog occurred under any of the conditions of RH to 20° C./85% RH, and good records could not be obtained.

(Effects of the Invention) According to the present invention, it is possible to provide an electrostatic recording sheet capable of obtaining good recording without toner fog, which often occurs in conventional electrostatic recording sheets using an insulating support. did it.

[Brief explanation of the drawing]

1 and 2 are conceptual diagrams for explaining the structure of the electrostatic recording sheet of the present invention, with FIG. 1 being a sectional view and FIG. 2 being a plan view. A: insulating support, B: conductive layer, C: dielectric layer,
D: Conductive band.

Claims (1)

[Claims] 1. In an electrostatic recording material formed by providing a conductive layer on an insulating support and further providing a dielectric layer thereon, the electrical resistance value is 1×10 ⁵ Ω/cm at both ends of the surface of the dielectric layer.
An electrostatic recording sheet characterized by being provided with a continuous conductive band as described below.