JPS62127744A - Electrostatic recording film - Google Patents

Abstract

PURPOSE:To stably obtain high-quality image with high-speed recording by applying a specific high-polymer binder to a dielectric layer. CONSTITUTION:The high-polymer binder to be used for the dielectric layer of an electrostatic recording film laminated with an insulating film, conductive layer and dielectric layer in this order consists essentially of halogenated polyolefin contg. 60-80wt% halogen. The weight ratio of the high-polymer binder and particles forming the dielectric layer is selected preferably within a 100/0.5-100/150 range. The stability of electric discharge is poor if the weight ratio is below said range and the film strength of the dielectric layer is low and such is undesirable if the weight ratio exceeds said range. The thickness of the dielectric layer is preferably 1-20mum. The surface potential is low if the thickness is smaller than said range and the resolution is poor and such is undesirable if the thickness exceeds said range.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an electrostatic recording film that directly converts an electrical signal into an electrostatic latent image.In particular, the present invention relates to an electrostatic recording film that allows high-quality images to be obtained during high-speed recording.

(Prior Art) An electrostatic recording film is known in which an insulating film, a conductive layer, and a dielectric layer are laminated in this order.

In the electrostatic recording method, a recording voltage is applied to a multi-pin electrode head (hereinafter abbreviated as pin electrode), and an air discharge is generated in a micro gap (hereinafter abbreviated as gap) between the pin electrode and the dielectric layer of the electrostatic recording film. An electrostatic latent image is formed on the surface of the dielectric layer, and then this electrostatic latent image is developed with toner to form a visible image. In order to obtain clear images in this way, it is necessary to control the gap within an appropriate range from the Paschen curve, and for this purpose, the gap is adjusted by adding insulating particles and bringing the pin electrode into contact with a dielectric layer with appropriate irregularities. The most commonly used method is to appropriately control the In such electrostatic recording films, clear images cannot be obtained unless insulating particles are added to the dielectric layer.

In recent years, there has been an increase in recording speed and image quality (16
In order to meet the requirements for dots/mm or more, it is necessary to discharge stably and uniformly with a shorter application time and lower applied voltage.To achieve this, it is necessary to always maintain a constant gap. Appropriate unevenness is formed on the surface of the dielectric layer of the electrostatic recording film to maintain this gap constant.

The applied force type of electrostatic recording that is currently mainstream includes (a)
There are three methods: single-sided control, (b) double-sided control, and (c) same-face control. Each method has a preferred range of surface roughness of the dielectric layer, and outside this range, pixel pitching and pixel thickening may occur. , and good image quality cannot be obtained. In general, electrostatic recording films have a narrower range of preferable surface roughness of the dielectric layer than paper-based electrostatic recording papers, especially the above (c).
It is noticeable. The table below shows the preferred range of the surface roughness (Rt) of the dielectric layer when the resolution is 8 to 10 lines/mm.

Faster recording and higher image quality (16 dots/m
m or more), the application time becomes shorter, and in order to stably and uniformly discharge at a lower applied voltage to prevent discharge between adjacent pin electrodes, the preferred dielectric layer range 1. (It becomes narrower, especially for method (c)), J9, Rt must be strictly controlled, making manufacturing difficult, and it is not possible to use it for other methods and for Ak, so it is classified separately. However, the details of why the preferred range of the surface roughness (Rt) of the dielectric layer for electrostatic recording films is generally narrower than that for electrostatic recording paper are not known.

(Problems to be Solved by the Invention) An object of the present invention is to eliminate the above-mentioned drawbacks and provide an electrostatic recording film having a dielectric layer that stably provides high-quality images with high-speed recording in any application method. That is.

(Means for Solving the Problems) In order to achieve the above object, the present invention has the following configuration.That is, in an electrostatic recording film in which an insulating film, a conductive layer, and a dielectric layer are laminated in this order, The dielectric layer is composed of particles of a polymeric binder, and the polymeric binder is mainly composed of halogenated polyolefin containing 60 to 80% by weight of halogen. That is.

Many polymeric binders for dielectric layers have been known, and it is also known that halogenated resins containing halogen atoms, such as polyvinyl chloride copolymers, can be used. However, the finding that only halogenated polyolefins with a specific halogen content function particularly effectively for the purposes of the present invention is surprising and completely unknown heretofore.

The polymer binder used in the dielectric layer in the present invention is 6
It mainly consists of halogenated polyolefin containing 0 to 80% by weight of halogen. Such halogenated polyolefins are those obtained by halogenating polyolefins, and include, for example, the following.

A, halogenated polyethylene and its copolymer B, halogenated polypropylene and its copolymer C, halogenated polybutylene and its copolymer, D,
Halogenated polyimbutylene and copolymers thereof, etc., with a halogen content of 60 to 80% by weight based on the polymer composition. If the halogen content is less than this, high-quality images cannot be obtained, while if it is more than this, the polymer has low solubility in solvents and therefore cannot be used as a polymeric binder. Two or more of these may be used in combination.

Halogenated polyolefins can be produced by commonly known methods. For example, it is produced by dissolving polyolefin in a halogenated solvent, heating it, halogenating it under pressure or vapor pressure, and then going through steps such as distillation, washing, and drying. Among the halogenated polyolefins, those containing a small amount of impurities such as halogen molecules, hydrogen halide, and other halogen compounds are preferably used. If necessary, known stabilizers, antioxidants, ultraviolet absorbers, etc. may be added to the halogenated polyolefin within a range that does not impair the characteristics of the present invention. Among the halogenated polyolefins, chlorinated polyolefins are particularly preferably used from the viewpoint of ease of production.

Further, other known polymer binders may be added as necessary within a range that does not impair the characteristics of the present invention.

Examples of such polymer binders include polyester, polyester amide, polyvinyl acetal, polyvinyl chloride, poly(meth)acrylate, polyamide,
Examples include polyurethane, polycarbonate, polystyrene, polymethylpentene, alkyd resin, polyamideimide, silicone resin, fluororesin, phenol resin, epoxy resin, and copolymers thereof. 60-80
The proportion of the halogenated polyolefin containing halogen in the total polymer binder is preferably 50% by weight or more, more preferably 70% by weight or more, and if it is less than this range, In this method, the preferable range of the surface roughness (Rt) of the dielectric layer becomes narrow, and the object of the present invention cannot be achieved.

Particles are used in the dielectric layer of the present invention to form gaps. As the particles, commonly known inorganic particles or organic particles are used. Such particles have a volume resistivity of 108
It is preferably at least Ω·cm, more preferably at least 1 oloΩ·cm. Examples of such inorganic particles include metal oxides such as silicon oxide, titanium oxide, alumina, lead oxide, and zirconium oxide; salts such as calcium carbonate, barium titanate, and barium sulfate; and examples of organic particles include styrene. - Suitably selected from divinylbenzene copolymer, melamine resin, epoxy resin, phenol resin, fluororesin, etc.

These particles may be used alone or in combination of two or more. The average particle size of the above particles is generally 0.1 from the viewpoint of discharge stability.
It is preferable to select the thickness appropriately within the range of 15 μm.

In the present invention, the weight ratio of the polymer binder and particles forming the dielectric layer is preferably selected within the range of 10010.5 to 100/150. If the weight ratio is lower than this,
The stability of discharge is poor, and if it exceeds this range, the film strength of the dielectric layer will weaken, which is not preferable.

The thickness of the dielectric layer is preferably 1 to 20 μm,
If it is thinner than this, the surface potential will be low, and if it is thicker than this, the resolution will be poor, which is not preferable.

The dielectric layer may be a single layer or a plurality of layers,
Further, an intermediate layer such as an adhesive may be provided between the conductive layer and the dielectric layer.

The dielectric layer of the present invention may contain plasticizers, adhesion promoters, stabilizers, antioxidants, ultraviolet absorbers, and lubricants as necessary to the extent that they do not impair the properties of the electrostatic recording film that is the object of the present invention. In addition, conductive powder or the like may be added to prevent fogging.

Generally known methods are effectively used to add the dielectric layer. For example, it is appropriately selected from brush coating, dip coating, knife coating, roll coating, spray coating, flow coating, rotary coating (spinner, whaler, etc.), and the like.

The insulating film used in the present invention is a film made of an insulating thermoplastic resin or thermosetting resin having a well-known volume resistivity of 10 12 Ω·cm or more. The resin for this film includes polyester, polyolefin, polyamide, polyesteramide, polyether, polyimide, polyamideimide, polystyrene,
polycarbonate, poly-p-phenylene sulfide,
Polyether ester, polyvinyl chloride, poly(meth)
Acrylic acid esters and the like are preferred.

A copolymer or blend of these or a crosslinked product of these may also be used. Further, it is preferable that these resins be stretched, since mechanical strength, dimensional stability, thermal properties, optical properties, etc. are improved. Among these, polyester is preferably used. Here, the polyester is a polyester containing an aromatic dicarboxylic acid as a main acid component and an alkylene glycol as a main glycol component.

Specific examples of aromatic dicarboxylic acids include terephthalic acid,
Isophthalic acid, naphthalene dicarboxylic acid, diphenoxyethane dicarboxylic acid, diphenyl dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid, diphenyl ketone dicarboxylic acid, anthracene dicarboxylic acid, α, β-bis(2-chlorophenoxy)
Examples include ethane-4,4"-dicarboxylic acid. Among these, terephthalic acid is particularly desirable.

Specific examples of alkylene glycol include ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, and hexylene glycol.

Of course, these polyesters may be homopolyesters or copolyesters (copolymerized polyesters), and examples of copolymerized components include diethylene glycol, propylene glycol, neopentyl glycol, polyalkylene glycol, p- Diol components such as xylylene glycol, 1,4-cyclohexane dimetatool, 5-sodium sulforesorcin, adipic acid, sebacic acid, phthalic acid, isophthalic acid,
Examples include dicarboxylic acid components such as 2.6-naphthalene dicarboxylic acid and 5-sodium sulfoisophthalic acid, polyfunctional dicarboxylic acid components such as trimellitic acid and pyromellitic acid, and oxycarboxylic acid components such as oxyethoxybenzoic acid. .

The thickness of the plastic film is 10 μm to 250 μm.
! It is preferable to stay in. Roughly preferably 15μ
It is desirable that the film has a thickness of m to 150 μm. If it is thinner than this, the film will not have sufficient mechanical strength, and if it is thicker than this, the film transportability will deteriorate, which is not preferable.

These plastic films may be subjected to known surface shielding, such as corona discharge treatment, plasma radiation treatment, anchor coating, etc., to improve adhesion, if necessary.

Furthermore, in order to prevent the occurrence of scratches during running, the insulating film has a static friction coefficient of 2.0 or less, preferably 1.0.
It is preferable that it is below.

As the conductive layer of the present invention, a commonly known conductive layer is used. The surface electrical resistance is preferably 10 4 to 10 9 Ω/mouth. Such conductive layers include (1) those made of electronically conductive metal oxides, (2) those coated with ionically conductive polymer electrolytes, and (3) conductive powder and polymer binder. or coated with a layer consisting of a polymer electrolyte.

In this case, commonly known electron conductive metals, metal compounds, ion conductive polymer electrolytes, and conductive powders are used. Such a preferable composition includes AD, Cr
, Cd, Ti, Fe, Cu, In, Ni,
Pd.

Pt, Rh, Ag, Ru, w, Sn, Zr
, metals such as Ir, stainless steel, brass, N1-Cr
Examples include, but are not limited to, metal oxides such as indium oxide, tin oxide, zinc oxide, titanium oxide, vanadium oxide, ruthenium oxide, and tantalum oxide, and metal compounds such as copper iodide. These may be used alone or in combination in a combination or mixture of two or more. Further, the polymer electrolyte includes, but is not limited to, quaternary ammonium salts, sulfonate salts, polyalcohols, and the like.

These may be used alone or in combination of two or more. Such a conductive layer may be formed by plating, vacuum deposition, chemical vapor deposition, sputtering, coating, or the like. Among these, an island-shaped discontinuous metal film made of a material mainly consisting of at least one metal selected from the group consisting of Rh, Pd, Ir, pt, and Ru is used to improve uniformity of surface electrical resistance and humidity. Stability against [particularly preferred from the viewpoint of raw materials, etc. Incidentally, an island-shaped discontinuous metal film is one in which metal particles are scattered on an insulating film, and the average size is in the range of 1Q-5 to 10-2 square microns. preferable. The density of the island-shaped discontinuous metal film is preferably 15 to 50% in terms of area fraction.

A laminate of the above insulating film and a conductive layer is called a conductive film.

The preferable range of the surface electrical resistance of the conductive layer is known depending on the recording method, and generally in (a) it is 104 to 108 Ω.
/mouth, (mouth) is 107~108Ω/mouth, (c) is 1
It is said that 06 to 107 Ω/mouth is preferable.

〔Effect of the invention〕

The present invention is an electrostatic recording film in which an insulating film, a conductive layer, and a dielectric layer are laminated in this order.Since a specific polymer binder is applied to the dielectric layer, high-speed recording is possible with any application method. It was possible to stably obtain high-quality images.

In particular, in the same-surface control method (c) in which the range of surface roughness R1) of the dielectric layer is generally extremely narrow, the range of Rt that allows high-quality images to be obtained with high-speed recording can be greatly expanded. For this reason, it is necessary to greatly expand the range of grain selection in the dielectric layer, increase the range of variation in the surface roughness (Rt) of the dielectric layer, and, as a result, use a dielectric layer common to each electrostatic recording method. This made manufacturing extremely easy.

As described above, the electrostatic recording film of the present invention has excellent properties, so it can be used not only as an electrostatic recording film for hard copies, for electrostatic recording printers/plotters, and for facsimiles, but also for repeated use. The electrostatic recording film used for the master film is transfer master for copying machines, facsimile receivers, and printers, and electrophotographic process using electrostatic latent image transfer method (TES).
It is useful as a recording medium that retains a transferred electrostatic latent image using method I), and as a recording film for displays using an electrostatic recording method.

[Method for measuring characteristics] (1) Cut the surface electrical resistance conductive film to a width of 30 mm, assume two flat 11 wires perpendicular to the cut line and spaced 30rr1m apart, and Apply conductive carphone paint to the right and left sides, excluding the areas covered by the wire, and use them as electrodes. The electrical resistance between the electrodes was measured at 20'C-65%R using a Keithley electrometer (type 6100L).
The surface electrical resistance of the electrostatic recording film, measured in H and expressed in Ω/unit, was also measured in accordance with this method.

(2) Image quality An electrostatic latent image was formed on the surface of the electrostatic recording film using a multi-pin electrode head, and then the electrostatic latent image was visualized using a wet toner developer and dried to obtain a hard copy image. . Three recording methods were selected as appropriate: (a) single-sided control, (c) double-sided control, and (c) same-sided 1i1J control.

(a) Printing was performed at 16 dots/mm after each pixel, and the number of rear pixels per 100 mm was measured. 80 or less is good, 81-250
251 or more were considered poor, and 251 or more were considered poor.

(b) Printing was performed with a pixel thickness of 16 dots/mm, and the number of pixels per 100 mm was measured. 60 or less is good, 61-20
0 pieces were rated as somewhat good, and 201 or more pieces were rated as poor.

(c) Image density The solid black image area is measured as a reflection density with a Sakura microdensitometer (model PDM-5>) and the opening degree is 0.
．． A value of 7 or more was considered good, and a value of less than 0.7 was considered poor.

(3) Surface Roughness Rt) The maximum roughness measured using a stylus type surface roughness meter is 1' (cut ono 0.25 mm, measurement width 4 mm, average value of n-5!, -).

(4) Transparency Japan Precision Optical 5PHER3METHODMETER (
TYPE SEP HS>, the total light transmittance at 550 nm was measured.

(Example〕 The present invention will be explained below with reference to Examples.

The present invention is not limited to these. Note that all blended parts in the examples are based on weight.

Examples 1 to 4 Pd was sputtered between 2111111 stretched polyethylene terephthalate films (“Lumirror” manufactured by Toshiku Co., Ltd.) with a thickness of 75 μm to increase the surface electrical resistance or 1×10
1q of 7Ω/hole conductive film. A dielectric layer having the composition shown in Table 1 was coated on this conductive film (thickness after drying: 3C]/m2), and the electrostatic recording film of the present invention (
Examples 1 to 4) were obtained. These image quality evaluations are summarized in Table 1. The composition of the dielectric layer was polymer binder/calcium carbonate-100150, and Rt was changed by changing the average particle size of calcium carbonate. In addition, to prevent fogging, both are made of conductive tin oxide (100Ω・cm).
was added in an amount of 0.5 parts to 100 parts of the polymer binder.

Comparative Examples 1 to 4 Comparative Examples 1 to 5 were obtained in the same manner as in Example 1 except that the dielectric layer composition was as shown in Table 1.

Examples 1 to 1 showing electrostatic recording films of the present invention from Table 1
4 is (c) It is clear that in high-resolution image quality planning using the same plane control method, a dielectric layer Rt of 1 to 12 μm is necessary for good image quality. On the other hand, in Comparative Examples 2 to 5 using conventional polymer binders, it is clear that the preferred range of Rt is only an extremely narrow range of 1 to 3 μm.

Examples 5 to 7 Examples 5 to 7 were conducted in the same manner as in Example 3.4 and Comparative Example 1 except that the surface electrical resistance of the raw film was as shown in Table 1. The image quality evaluations 1i11i are as shown in Table 1, and all were good. Example 8.9 Example 8.9 was obtained in the same manner as in Example 4, except that the dielectric layer composition was the same as shown in Table 1.

The image quality evaluations are as shown in Table 1, and all were good.

The electrostatic recording films of Examples 1 to 9 of the present invention all had good transparency of 70% or more, and were also excellent as transparent films for CAD (interactive design) electrostatic plotters.

Comparative Example 5 Comparative Example 6 having an Rt of 12 μm was obtained in the same manner as in Example 19, except that the polymer binder was chlorinated polyethylene (chlorine: 57%). In the image quality evaluation using the same plane control method (16 dots/mm), there were many pixel distortions and the result was poor. In comparison with Example 9, in the present invention, the polymeric binder of the dielectric layer must be a halogenated polyolefin containing 60% by weight or more of halogen.

Claims (1)

[Claims] (1) In an electrostatic recording film in which an insulating film, a conductive layer, and a dielectric layer are laminated in this order, the dielectric layer is
1. An electrostatic recording film comprising a polymeric binder and particles, the polymeric binder mainly consisting of a halogenated polyolefin containing 60 to 80% by weight of halogen.