JPH0329961A - Liquid developer for magnetography - Google Patents

Abstract

PURPOSE:To improve the dispersion stability of a magnetic toner essentially consisting of magnetic particles, coloring agent and binder and to retard the evaporation of a carrier liquid essentially consisting of a specific solvent so that visible images having high resolution are obtd. by dispersing the above- mentioned magnetic toner into the above-mentioned carrier liquid, thereby forming the developer. CONSTITUTION:This developer is formed by dispersing the magnetic toner essentially consisting of the magnetic particles, the coloring agent and the binder into the carrier liquid essentially consisting of the solvent A expressed by formula I. The carrier liquid essentially consisting of this solvent A has an alkyl group of a nonmagnetic group in the molecule and an acyl group of a polar group. The polarity of the carrier liquid can, therefore, be controlled and the dispersibility of the magnetic toner is good. The solvent A has low volatility and moderate solubility of an org. high polymer so that the high polymer dispersant suitable for the dispersion of the magnetic toner can be selected. The dispersibility of the toner is good and the evaporation of the carrier liquid is retarded. The visible image having the high resolution is thus obtd.

Description

[Detailed Description of the Invention] Industrial Application Fields The present invention relates to a liquid developer for magnetic flux graphics.
In particular, the present invention relates to a liquid developer for magnetography that has good dispersion stability of magnetic toner, extremely slow exfoliation of carrier liquid, and is capable of producing high-resolution images.

Conventional technology> Magnetography generally scans a magnetic recording medium with a magnetic material on the surface to form a magnetic latent image, and after developing this magnetic latent image with magnetic toner, pressure is applied to the transferred object. Alternatively, a visible image is obtained by electrostatically transferring and fixing. In particular, it has the advantage that a plurality of visible images can be efficiently obtained by repeating the development and transfer steps in one latent image form.

In this magnetography, the quality of the visible image, especially the resolution, is determined by the properties of the magnetic toner used.

By the way, in the electrostatic photography method, liquid developers have been developed in order to obtain high-resolution visible images, and some of them have been put into practical use. Liquid developers for electrostatic photography mainly consist of 71 colorants made of carbon blanks, organic pigments, dyes, etc., and binders made of organic polymers such as acrylic resins, phenol-modified alkint resins, and synthetic rubbers. To this, polarity control agents such as lecithin, linseed oil, metal sesoken, and higher fatty acids were added.
This is a carrier liquid in which a polymeric dispersant is dissolved. Liquid developers for electrostatic photography need to have an electrostatic charge on their surface, so the carrier liquid needs to be a solvent with high insulating properties and low dielectric constant, such as aromatic hydrocarbon, aliphatic hydrocarbon, For example, Isopar (manufactured by Exxon)
is commonly used.

These carrier liquids used in electrostatographic liquid developers have low solvent polarity and extremely high solubility (low solubility), which limits the types of polymeric dispersants that can be used and It has poor properties, is volatile, and has a problem with its odor.

It is expected that high-resolution visible images can be efficiently obtained by using a liquid developer in magnetic imaging. However, there have been very few examples of development regarding liquid developers for magfography.For example, in Japanese Patent Publication No. 50-40622, a liquid developer for electrostatic photography was developed in a magnetic printing device that uses a combination of magnetic action and electrostatic action. Used in developer; }
- There are some cases in which Yaria liquid is used as a carrier liquid for liquid developers for magnetography.

<Problems to be Solved by the Invention> The present invention has been developed by examining the composition strength of a liquid developer in conventionally known magnetography. The present invention relates to a liquid developer for magnetic graphics that has good stability, extremely slow blooming of the carrier liquid, and provides visible images with high resolution.

<Means for Solving the Problems> The present invention has been made in view of the above-mentioned current situation, and specifically, H3C-0-C1(CI.) of general r(), l-C
-O-C II. 1111 0 0 . . . Magne 1 GRAPH JTI, which is made by dispersing magnetic particles, a coloring agent, and a binder as main components in a carrier liquid whose main components are a solvent 8 represented by /Pj
．． The magnetic 1-ner has good dispersion stability, and the carrier liquid evaporates very slowly.
The present invention proposes a liquid developer for Magne I graphics that can provide high-resolution visible images.

<Detailed description of the invention> The present invention will be explained in more detail below.

What is the typical composition of the liquid developer for mag lithography invented by Kiyoshi? Night Body Polymer dispersant, magnetic toner, and dispersion aid made of organic polymers that dissolve in this carrier liquid.

The carrier liquid, which is the most important component in the present invention, must satisfy safety, low volatility, nontoxicity, and low odor, and must maintain dispersion stability of the magnetic toner. In addition, the magnetic toner does not need to have an electrostatic charge, and it does not need to be a highly insulating, low dielectric constant aliphatic hydrocarbon or aromatic hydrocarbon solvent used in conventional electrostatic photographic liquid developers. do not have.

As a result of testing various solvents to meet the above requirements, the present inventor found that the carrier liquid used in the liquid developer for mag nontography is general 2 1-13 C-○-C-(
CI. ). 1C -0 -C Ii. 1111 0 0...■
It has been found that a carrier liquid containing the solvent 8 as the main component is optimal.

The -1-Yaria liquid, which is mainly composed of solvent 8 shown in General 2, has an alkyl group, which is a nonpolar group, and an acyl group, which is a polar group, in the molecule. Therefore, the polarity of the carrier liquid can be controlled, and the dispersibility of the magnetic 1.ner is extremely good. In addition, solvent A represented by the general formula has low volatility,
Furthermore, the solubility of the organic polymer is moderate, and it is possible to select a polymer dispersant most suitable for dispersing magnetic 1.ner.

The carrier liquid described above needs to be appropriately selected depending on the composition of the magnetic toner used and the application of the magnetography used. In addition, it is also possible to use a mixture of two or more solvents represented by the general formula, mixtures of the solvent represented by the general formula (1) and higher alcohols and higher alcohol derivatives, and mixtures of the solvent represented by the general formula and polyhydric alcohols and their derivatives. When used in a carrier liquid, it is effective in controlling the volatilization rate, dissolution ability, magnetic 1, and dispersion stability of the carrier liquid.

Magnetic 1-ner mainly consists of magnetic particles, a coloring agent made of pigments and dyes, and a binder made of an organic polymer.

As the magnetic particles, commonly known magnetic materials such as iron, cohardt, chromium oxide, various ferrites such as nylon zinc ferrite, manganese zinc ferrite, etc. are used, and the particle size is determined depending on the purpose of the magnetic toner used. However, 0.01 μrn to 10 μm, preferably 0.03 μm
~1.0 μm.

Further, the colorant is not particularly specified in the present invention, and various known pigments and dyes such as those used in electrostatic photographic toners can be used. For example, acetylene filler/drug, carbon filler/drug such as chenodiene filler, nigrosine, methylene blue.
Examples include lid cyanine blue.

The binder must not be dissolved in the above-mentioned carrier liquid and must have transfer-fixing properties to the transferred material, such as urethane resin, cellulose ether resin, polyester resin, acrylic resin, methacrylic resin, styrene resin, polyolefin resin, etc. Phenol-modified alkyd resin, synthetic rubber, etc., or their polymer blends and copolymer resins, etc.
It can be selected from commonly used organic polymers.

The polymeric dispersant is appropriately determined depending on the type of carrier liquid and the type of magnetic 1-ner configured as described above. Generally, the polymer dispersant is preferably a block polymer or a copolymer polymer having a segment soluble in the carrier liquid and a segment 1 that is sparingly soluble in the carrier liquid. In particular, when the poorly soluble segment 1. has a chemical structure similar to the binder of the magnetic 1.ner, the magnetic toner can be stably dispersed. In addition, if this polymeric dispersing agent is adsorbed to the surface of the magnetic 1-toner, chemically bonded, or kneaded into the magnetic 1-toner, the steric repulsion of the polymeric dispersant stabilizes the magnetic toner. It can be dispersed into This polymer dispersant can be obtained by copolymerization, graft polymerization, or block polymerization of various monomers, but the method is not limited to these methods and various methods can be used.

Furthermore, if the magnetic materials are well dispersed in the carrier body, there is no need to add polymeric degradation stabilizers.

In addition, the separation aids are those that improve the dispersibility of the magnetic 1-ner, and include various surfactants, lower alcohols and their derivatives, metal soaps, flax, higher fatty acids, and fine silica powder. used.

Furthermore, it is also possible to add a soluble polymer to the carrier liquid to improve the transfer and fixing properties of the magnetic toner to the transferred object.

As the method for producing the liquid developer for magnetic imaging according to the present invention, a conventionally known method for producing a liquid developer for electrostatic photography can be applied. An example of the manufacturing method will be shown below.

Add the above-mentioned magnetic particles, colorant, binder, and if necessary a surfactant, and knead in a ball mill, roll mill, paint shaker, three-roll, etc. solvent in the binder. After 1 kneading, a 1 kneaded product is obtained, and the parent solvent is removed by heating or the like to obtain a 7 kneaded product. Alternatively, the kneaded material is poured into a solvent that does not dissolve the binder, and the binder is precipitated to obtain a mixture. Alternatively, the mixture is obtained after kneading with a kneader such as a kneader or three rolls while heating the magnetic spatula, colorant, binder, and, if necessary, a surfactant above the softening point of the binder. . The mixture thus obtained is subjected to dry pulverization method or 6J. A magnetic 1.ner is obtained by a wet grinding method in which the material is ground together with a solvent. As the solvent for wet grinding, the carrier liquid of the present invention may be used, or 1 to 20 parts of the parent solvent of the binder may be added.

The carrier liquid of the present invention and, if necessary, the above-mentioned polymeric dispersant, dispersion aid, and polymer soluble in the carrier liquid are added to the thus obtained Magnetic 1 to 1. A liquid developer for graphics is obtained. In addition to the methods described above, the polymer dispersant and the separation aid may be added during kneading or wet grinding, or they may be added in combination.

The concentration of [Magnetic] hener in the liquid developer for magnetography is not particularly limited, but is 0.01 wt% to 1.0 wt% with respect to the carrier liquid of the present invention. It is about Owt%. In addition, the concentration of the polymer dispersant is O. OO1wt%~
Although it is preferable to adjust Q, lwt%, it is not particularly limited and can be determined as appropriate.

<Function> In the liquid developer for magnetography according to the present invention, by considering the composition of the liquid developer, it is possible to achieve good toner dispersion stability, extremely slow blooming of the carrier liquid, and high resolution. A liquid developer for mag atonography from which a visual image can be obtained is obtained.

<Example> This will be explained in detail below using Examples.

Example 1. Binder: 75 parts by weight of styrene-acrylic acid ester copolymer resin, 10 parts by weight of Meradan resin, 5 parts by weight of chlorinated polypropylene I Colorant: 10 parts by weight Carbon black Magnetic particles Nickel zinc ferrite fine powder (average particles) After kneading 0.1 parts by weight of IO surfactant and fluorine-based surfactant in a paint shaker using methyl ethyl ketone, it was mixed with the following formula H. C101C 1 (C H Z) 2-C -0
500 ml of a carrier liquid consisting of a solvent represented by -C H I+l111 00 was added, and methyl ethylgein was ignited by heating to obtain a mixture A. This mixture A was further wet-pulverized using a paint shaker to obtain a magnetic toner having an average granule diameter of 0.36 μm.

Furthermore, after adding 500 ml of the carrier liquid in which a polymeric dispersant made of polyvinyl alcohol partially saponified with lauric acid was added, fine silica powder (particle size 0.03 μm) was added.
) 2g of dispersion aid was added to make the solid content concentration 1.5w.
A liquid developer for magnetography was obtained by adjusting with a carrier liquid so that the developer was t%.

The above-mentioned liquid developer for magnetography showed good redispersion of magnetic toner after 30 days, and expulsion of carrier liquid was 5% or less. Furthermore, a fine line of 5 μm could be developed using a wet magnetography developing machine.

Example 2. Binder - 100 parts by weight of maleic acid-modified polypropylene Colorant - 10 parts by weight Carpon blank - 1 part by weight of copper cap cyanine Mixture B was obtained by kneading with a roll.

5 parts by weight of xylene, which is a parent solvent, and 500 ml of a carrier liquid consisting of a solvent shown by the formula for the binder were added to the second mixture B, and the mixture was ground with a ball mill for 45 hours, and the average particle size was 0.6.
A magnetic toner with a diameter of 0 μm was obtained.

Furthermore, a soluble polymer is added to a polymer dispersant made of styrene-butadiene block polymer and a carrier liquid made of nitrocellulose, and the solid content is adjusted to 1.5 wt% with the carrier liquid. A liquid developer for graphics was obtained.

The above-mentioned liquid developer for magnetography showed good redispersion of magnetic toner after 30 days, and expulsion of carrier liquid was 5% or less. Furthermore, a fine line of 5 μm could be developed using a wet magnetography developing machine.

Example 3. Binder - Polyurethane resin 80 parts by weight - Eboxy resin 20 parts by weight - Vinyl chloride-vinyl acetate copolymer resin IO heavy area Colorant - Carbon plaque 10 parts by weight - Medielene blue - 1 part by weight Magnetic particles - Fine ferrite powder (average Add 500 parts by weight of ethylene glycol diethyl ether to 0.1 parts by weight of surfactant/fluorosurfactant (particle size: 0.12 μm),
Mixture C was obtained by kneading in a sand mill.

To this mixture C, 1000 ml of a carrier liquid consisting of a solvent shown by the formula was added, and the mixture was pulverized with a Santo mill, and the average particle size was 0.34μ.
A magnetic 1·ner of m was obtained.

Furthermore, a polymer dispersant consisting of a copolymer resin of lauryl methacrylate-1 and 2-hydroxyl methacrylate-1
A soluble polymer was added to a carrier liquid made of nitrocellulose, and the solid content concentration was adjusted to 1-5 wt% with the carrier liquid to obtain a liquid developer for magnetography.

The above liquid developer for magnetography showed good redispersion of the magnetic toner after 30 days, and evaporation of the carrier liquid was 5% or less. Furthermore, a fine line of 5 μm could be developed using a wet magnetography developing machine.

Effects of the Invention> The present invention is as described above, and by considering the composition of the liquid developer in a liquid developer for magnetography, the dispersion stability of the toner is good and the evaporation of the carrier liquid is extremely slow. We were able to provide a liquid developer for magnetography that can provide a high-resolution visible image.

Claims (1)

[Claims] (1) A magnetic latent image consisting of a magnetized image area and a non-magnetized non-image area is developed on a magnetic material using a liquid developer for magnetography, and is transferred and fixed onto the transfer target, resulting in a visible image. In magnetography, the liquid developer for magnetography is mixed into a carrier liquid containing solvent A as the main component represented by general formula (1) ▲Mathematical formula, chemical formula, table, etc. , a liquid developer for magnetography comprising a magnetic toner containing magnetic particles, a colorant, and a binder as main components dispersed therein.