JPS63167376A - Method and device for electrostatic recording - Google Patents

Abstract

PURPOSE:To obtain a clear image prevented from the lacking of thin lines or abnormal discharge by allowing organic solvent evaporating gas to exist between an electrostatic recorder and multi-stylus electrode. CONSTITUTION:The organic solvent evaporating gas is allowed to exist between the electrostatic recorder and the multi-stylus electrode and the electrostatic recorder allows the organic solvent with 30-300 deg.C boiling point to be contained in the multi-stylus electrode with 5.0X10<-5>-1.0g/m<2> concentration at the time of forming a latent image on the recorder. For instance, hydrocarbon such as ethyl alcohol, hexyl alcohol and ethyl ether is independently or mixedly used as the organic solvent existing or contained in the electrostatic recorder. Consequently, clear recording pictures prevented from the lacking of thin lines or abnormal discharge can be obtained.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to an electrostatic recording method and an electrostatic recording method suitable for electrostatic facsimiles for high-density recording such as 400 dots/inch, electrostatic printers, electrostatic plotters, etc. It's about the body.

(Prior art) Along with advances in communication technology, electrostatic recording methods have been widely used as a recording method that simultaneously satisfies high-speed recording and high image quality. Examples of this include optical communications and computer output equipment. Examples include fax machines and printers. In particular, in recent years, electrostatic printers and electrostatic plotters capable of high-density recording have been favorably used for outputting drawings such as CAD systems for designing and drawing using computers.

The multi-needle electrode recording method most commonly used in electrostatic recording methods includes single-sided control type and double-sided control type, but in both cases, recording of about 200 dots/inch is mainly used for recording text. In terms of density, there was no problem with the discharge itself, probably because the area of each recording needle was sufficient.

However, when high-density recording of about 400 dots/inch is performed using a conventional electrostatic recording material, mainly for the purpose of recording drawings, when thin lines are drawn, normal discharge does not occur and the recording is not recorded after development. The so-called thin line-like phenomenon occurs where parts appear, and conversely, depending on the location, the discharge may be as small as 1 part of the area of each needle electrode.
0 times or more, and an abnormal discharge occurs in which points with abnormal bulges appear in the thin line after development, making it impossible to obtain good recording.

Conventionally, we focused on the relationship between the smoothness of the dielectric layer surface and recording suitability, and in order to accurately keep the distance between the multi-needle electrode and the dielectric layer surface within an appropriate range, we investigated the surface roughness of the dielectric layer, the number of unevenness, etc. Although attempts have been made to improve the control to an appropriate level, the current situation is that thin wire omissions and abnormal discharge remain unsolved.

(Problems to be Solved by the Invention) The present invention provides an electrostatic recording method and an electrostatic recording medium that can obtain clear images without thin line omission or abnormal discharge in high-density recording such as 400 dots/inch. The purpose is to

(Means for Solving the Problem) In order to achieve the above object, the present inventors have conducted extensive research and found that the above problems can be solved by causing vaporized organic solvent gas to exist between the multi-needle electrode and the electrostatic recording medium. The inventors have found that this problem can be solved, and have completed an invention consisting of the following configuration.

Particularly, the present invention is an electrostatic recording method for forming a latent image on an electrostatic recording medium using a multi-needle electrode, characterized in that an evaporated gas of an organic solvent is present between the electrostatic recording body and the multi-needle electrode. It is an electrostatic recording method that uses a multi-needle electrode to form a latent image on the electrostatic recording medium in which a dielectric layer is formed on a conductive support. At the time when the electrostatic recording material is exposed to an organic solvent having a boiling point of 30-300°C
It is an electrostatic recording material characterized by containing ~1.0 g/m2.

(Function) In the present invention, the organic solvents present or contained between the electrostatic recording material and the multi-needle electrode or in the electrostatic recording material include ethyl alcohol (79°C), hexyl alcohol (15
6°C), ethyl ether (35°C), methyl ethyl ketone (80°C), xylene (ortho 144°C, meta 13
9℃, para 138℃), toluene (111℃), or pentane (36℃), hexane (69℃), heptane (98℃), octane (126℃), decane (174℃)
), tridecane (234℃), hexadecane (287℃)
Examples include hydrocarbons such as (the number in parentheses indicates the boiling point), and these may be used alone or in combination. Note that when selecting an organic solvent, if one that dissolves a large amount of the resin used in the dielectric layer is used, the dissolved resin will adhere to the multi-needle electrode and reduce the quality of the recorded image. It is preferable that the electrostatic recording device be free of odor, have little odor, and have no adverse effect on the electrostatic recording device. Furthermore, it is desirable to use a substance that does not reduce the recorded image density, or a substance that does not deteriorate the developer by mixing with the developer, reducing the recording density or shortening the life of the developer.In general, it is a substance with weak polarity or fish-like properties, such as hydrocarbons. is preferable because it does not reduce image density and at the same time does not promote deterioration of the developer.

In the present invention, the method of making vaporized organic solvent exist between the multi-needle electrode and the electrostatic recording material includes supplying the vaporized gas directly near the multi-needle electrode, and positioning the electrostatic recording material under that atmosphere. There is a method of forming a latent image, or a method of first applying the above-mentioned organic solvent to the electrostatic recording material and causing its evaporated gas to exist between the electrostatic recording material and the multi-needle electrode.

In the latter case, if the amount of organic solvent applied is too small, most of the organic solvent will scatter before the electrostatic recording material reaches the multi-needle electrode, making it difficult to obtain a sufficient effect of eliminating thin wire omissions and abnormal discharge. If the amount of solvent applied is too large, an excessive amount of organic solvent will remain in a liquid state when forming a latent image with a multi-needle electrode, and a recorded image may not be obtained, or even if a recorded image is obtained, abnormal discharge may occur. The problem is that it increases. Therefore, the amount of organic solvent to be contained in the electrostatic recording medium is 5.0×10−' to 1.0×10 −′ at the time when the multi-needle electrode forms a latent image on the electrostatic recording medium.
Og/m" more preferably 5.OX 10-' to 1°0
A range of 'X 10-'g/m'' is desirable, and for that purpose it is necessary to pre-contain an appropriate amount of an organic solvent with an appropriate boiling point range in the electrostatic recording medium. When using organic solvents, the organic solvent may be applied in advance in a slightly larger amount than the above range, taking into account scattering, so the content should be set at 1.0.
g/m'' or more, for example, about 5 g/m''. In addition, if the boiling point of the organic solvent is too low, most of the electrostatic recording material will scatter before it reaches the multi-needle electrode, making it difficult to obtain a sufficient effect, and if the boiling point of the organic solvent is too high, it will evaporate into gas. It is difficult to obtain a sufficient recording improvement effect. Therefore, such an organic solvent has a boiling point of 30 to 300°C, more preferably 60 to 300°C.
A temperature of 280°C, most preferably 100 to 250°C is used.

Among the various organic solvents used in the present invention, saturated hydrocarbons are particularly excellent in terms of solubility in the dielectric layer, odor, influence on electrostatic recording devices and developers, and recorded image density. There are some, but among them, the boiling point is 30-30
Those with a boiling point of 60 to 280°C include, for example, those with a boiling point of 6 to 15 carbon atoms, and those with a boiling point of 100 to 250°C.
For example, saturated hydrocarbons containing various isomers having 8 to 13 carbon atoms are included.

In the present invention, by allowing vaporized gas of an organic solvent to exist between the multi-needle electrode and the electrostatic recording material, it is possible to prevent fine line omission, particularly
It is possible not only to completely eliminate missing dots during dot recording, but also to eliminate abnormal discharges that occur particularly frequently during single dot recording.The reason for this effect is not necessarily clear, but the above-mentioned evaporated gas It is speculated that this is because the discharge environment changes due to its presence.

In the present invention, the following methods are exemplified as methods for incorporating an organic solvent into an electrostatic recording material and using the evaporated gas thereof. Incidentally, when applying, transferring, and spraying an organic solvent to an electrostatic recording medium, it is usually applied to the dielectric layer surface, but it is also possible to apply the organic solvent to the back surface and then roll it up to overlap the front and back sides and transfer the organic solvent.

(1) Apply the organic solvent to be contained to the electrostatic recording medium using a bar coater, roll coater, etc., dry as necessary, and add the appropriate amount, or dilute the organic solvent with a low boiling point solvent, Apply in the same manner, dry, and remove the low boiling point solvent (method.

(2) A method in which the electrostatic recording material is sprayed with an organic solvent or a diluted solution of the organic solvent with a low boiling point solvent, and dried if necessary.

(3) A method in which a diluted solution of an organic solvent or a low boiling point solvent is applied to the surface of a roll that comes into contact with the surface of the electrostatic recording material in each manufacturing process of the electrostatic recording material, and the diluent is transferred to the electrostatic recording material.

(4) In each manufacturing process of an electrostatic recording medium, a sheet of paper, film, etc. is coated or impregnated with a diluted solution of an organic solvent or a low boiling point solvent, and the electrostatic recording medium running on the sheet is coated or impregnated with a diluted liquid using a roll or the like. A method in which an organic solvent or diluent is transferred to an electrostatic recording medium by pressing it against the electrostatic recording medium.

(5) A method in which the electrostatic recording material is exposed to a gaseous atmosphere of an organic solvent to be contained and absorbed.

In the present invention, when an evaporated gas of an organic solvent is supplied between the multi-needle electrode and the recording material from a source other than the electrostatic recording material, it is not necessarily necessary to contain the organic solvent in the recording material itself.

If the electrostatic recording device is equipped with a heating means and an electrostatic recording medium containing an organic solvent is heated, sufficient vaporized gas can be obtained even when an organic solvent with a relatively high boiling point is used.

The conductive support for forming the electrostatic recording medium may be an inorganic salt such as sodium chloride, a cationic polymer electrolyte such as polyvinylbenzyltrimethylammonium chloride, or an anionic polymer electrolyte, a surfactant, or an oxidized polymer. Impregnated or coated with metal oxide semiconductor powder such as zinc or zinc oxide treated to make it conductive, the surface resistivity is set to 105~10.
Paper, plastic film, cloth, etc. with a resistance of 10 days are used. As the resin for the dielectric layer constituting the electrostatic recording medium, methacrylic acid derivatives such as methyl methacrylate and butyl methacrylate, various polymers such as acrylic esters,
An insulating resin such as butyral resin is used, and pigments to be mixed therein include calcium carbonate, titanium oxide, amorphous silica, fired clay, and plastic pigments.

Examples of the present invention will be described below, but it goes without saying that the present invention is not limited to these Examples.

(Example) A cationic polymer electrolyte (trade name: Chemistat 6300° manufactured by Sanyo Kasei Co., Ltd.) was placed on the surface of a high-quality paper with an absolute dry weight of 3 g/m'' and 2 g on the back side of a high-quality paper with a surface area of 153 g/m2. /m2 to obtain a conductive support.

A paint prepared by mixing calcium carbonate powder with an average particle size of 5 μm and polymethyl methacrylate resin at a ratio of 1:1 was applied onto a conductive support so that the dry weight was 5 g/m', and electrostatic recording was performed. composed the body.

Electrostatic plotter EP-1 for CAD system made by Xingfeng Wide and Narrow High Matsushita Electric Transmission @
A pattern pattern was recorded using 01AI, and the image density was measured (image densitometer RD-10OR).

Manufactured by Macbeth). Furthermore, one dot of a thin line was recorded, and line omissions and abnormal discharge were visually evaluated.

Example 1 1 g 7 m of a saturated hydrocarbon mixture with a boiling point of 158 to 177°C diluted 100 times with n-hexane (trade name: 15OPARc, Shell Oil) was placed on the surface of the dielectric layer of an electrostatic recording material.
A recording test was carried out by spraying and air drying for 30 seconds to remove n-hexane (Fig. 1).

Example 2 A saturated hydrocarbon mixture (trade name: 15OPARM, Shell Oil) with a boiling point of 207 to 257°C diluted five times with n-hexane (trade name: 15OPARM, Shell Oil) was sprayed onto the surface of the dielectric layer of an electrostatic recording material. A recording test was performed after air drying for 30 seconds to remove n-hexane (Figure 2).

Example 3 A recording test was carried out in the same manner as in Example 1, except that a saturated hydrocarbon mixture with a boiling point of 115-142°C (trade name: 15OPARE, Shell Oil) was used instead of a saturated hydrocarbon mixture with a boiling point of 158-177°C. I went (Figure 3).

Example 4 Ethyl alcohol was sprayed at 0.1 g/m'' onto the dielectric surface of an electrostatic recording medium, and a recording test was immediately conducted (
Figure 4).

Example 5 Toluene was sprayed onto the surface of the dielectric layer of an electrostatic recording material.
2g/m” was sprayed and a recording test was immediately conducted (Figure 5).
.

Comparative Example 1 A recording test was carried out in the same manner as in Example 1, except that the n-hexane diluted solution of the saturated hydrocarbon mixture was not sprayed onto the electrostatic recording medium (FIG. 6).

Comparative Example 2 A recording test was immediately conducted by spraying 1.5 g/m of a saturated hydrocarbon mixture (trade name: I5OPARG, Shell Oil) with a boiling point of 158 to 177°C onto the dielectric layer of an electrostatic recording medium. (Figure 7).

The above test results are shown in Table 1. In Examples 1 to 5 according to the present invention, recordings with almost no thin line omissions or abnormal discharges were obtained, and an excellent improvement effect was observed (Figs. 1 to 5). On the other hand, in Comparative Example 1, in which the recording material did not contain an organic solvent, thin line omissions and abnormal discharge were observed (Figure 6), and in Comparative Example 2, in which an excessive amount of organic solvent was contained, abnormal discharge was noticeable, and both records were recorded. Aptitude was poor (Figure 7).

The evaluation criteria in Table 1 are as follows: Thin line omission ◎: Thin line omission is almost not observed O: Thin line omission is slightly observed ×: Thin line omission is significant, recording is poor Abnormal discharge ■ = Almost no abnormal discharge is observed No ○: Slight abnormal discharge is observed △: Abnormal discharge is observed and recording is poor. ×: Abnormal discharge is significant and recording is poor (effect). It was an excellent electrostatic recording method and recording medium that could obtain clear recorded images without thin line omissions or abnormal discharge even in the case of .

[Brief explanation of the drawing]

Figures 1, 2, and 3 are Example 1 and Example 2, respectively.
, are recording samples when one dot recording was performed by the electrostatic recording method according to the present invention in which saturated hydrocarbon was used as the organic solvent in Example 3, and FIGS. Alcohol (Example 4), l-
This is a recording sample of the present invention using luene (Example 5). Figures 6 and 7 show records obtained in the same manner when no organic solvent was used (Comparative Example 1) and when an excessive amount of organic solvent was contained in the recording medium (Comparative Example 2), respectively. This is a sample.

Claims (2)

[Claims] (1) In an electrostatic recording method in which a latent image is formed on an electrostatic recording medium using a multi-needle electrode, the electrostatic recording method is characterized in that an evaporated gas of an organic solvent is present between the electrostatic recording body and the multi-needle electrode. Recording method. (2) In an electrostatic recording material formed by forming a dielectric layer on a conductive support, the boiling point of the electrostatic recording material is 30 An electrostatic recording material characterized by containing 5.0 x 10^-^5 to 1.0 g/m^2 of an organic solvent at ~300°C.