JPH06138718A - Electrophotographic liquid developer - Google Patents

Abstract

PURPOSE:To provide the electrophotographic liquid developer which can form high-resolution images, obviates fogging and tailing of images, has an excellent color superposing characteristic and has good fixability to a body to be printed and a long life even in a development method in which a toner-on-toner system is adopted like in the case of development of a single pass system. CONSTITUTION:The resin of the electrophotographic liquid developer prepd. by dispersing toners essentially consisting of coloring agents and resin in an insulating carrier liquid consists of at least >=1 kinds of resin particles insoluble in the carrier liquid. The particles of <=0.1mum grain size occupy >=30vol.% of the entire part of these resin particles. The coloring agents are formed by coating >=1 kinds selected from pigments and dyes with the resin insoluble in the carrier liquid. In addition, the electrophotographic liquid developer contains an org. compd. soluble in the insulating liquid carrier contg. bi- to quadrivalent metals as a charge control agent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid developer for electrophotography, which is mainly used for developing an electrostatic latent image.

[0002]

2. Description of the Related Art In the field of image forming technology, methods called electrophotographic method, electrostatic recording method, electrostatic printing method and the like have been conventionally known. In these methods, a latent image by electrostatic charge is used. Is formed, and the obtained electrostatic latent image is visualized by developing it with a toner containing a colorant and a resin as main components. As a developer used for developing such an electrostatic latent image, a liquid developer in which particulate toner (toner particles) is dispersed in an insulating carrier liquid is known. In this liquid developer, In many cases, for example, when Isopar is used as the insulating carrier liquid, a clear image can be obtained when the solid content concentration in the liquid developer is low to some extent. A method of using a concentrated conc. Solution has been adopted. In this case, the toner image is developed on a material to be printed such as paper or film and is fixed by a process such as heat pressure or solvent evaporation. Further, depending on the intended use, the image is transferred again to a cloth, a film or the like, and the obtained image is utilized for costumes, advertisements and the like.

By the way, many proposals have been made for a liquid developer used for developing such an electrostatic latent image, but any of them has a problem that image fog or tailing easily occurs. Yes, none have satisfactory performance. In particular, a method called a toner-on-toner method is used in a method of forming a color image in one pass, such as a single-pass method. An image is formed by forming a subsequent electrostatic latent image and developing it on the solvent before the solvent is completely dried. Is likely to occur,
For this reason, image fogging and tailing are likely to occur,
There is a problem in that there are many places where the color overlapping property is insufficient. Therefore, there has been a demand for the development of a liquid developer having a good color superposition property in the single-pass system development.

Further, it is difficult to match the ratio of the colorant and the fixing resin consumed by the development with the ratio of the colorant and the fixing resin in the liquid developer, and the charge in the liquid developer is always constant. Since it is difficult to keep the liquid developer, the liquid developer has a life, and it is necessary to replace it with a new liquid developer after a certain number of times of use, but there is a problem that the life at this time is short.

[0005]

Therefore, the inventors of the present invention can exhibit an excellent color superimposing property even in the single-pass development, and have a good fixing property to a printing medium, and As a result of earnest research on the development of a liquid developer having a long life, by elucidating the charge retention function of the constituent components of the liquid developer, the liquid developer capable of exhibiting the charge retention function sufficiently can be obtained. The present invention has been completed by finding combinations of constituents. Therefore, the object of the present invention is to sequentially perform the subsequent formation of the electrostatic latent image and the development thereof before the solvent of the image of the preceding stage is completely dried, as in the case of the development of the single pass method. High-resolution images can be formed even in the developing method that employs a toner-on-toner method that forms images by superimposing images, and there is no image fogging or tailing, and excellent color superimposition. Another object is to provide a positively charged liquid developer for electrophotography. Another object of the present invention is to provide an excellent liquid developer for electrophotography, which has good fixability on a material to be printed and has a long life.

[0006]

That is, the present invention provides a liquid developer for electrophotography, which comprises a toner having a resin and a colorant as main components dispersed in an insulating carrier liquid. At least one type of resin particles insoluble in the carrier liquid, particles having a particle size of 0.1 μm or less account for 30% by volume or more of the entire resin particles, and the colorant is one or more types selected from pigments and dyes. Is formed by coating the insulating carrier liquid with an insoluble resin and contains an organic compound soluble in the insulating carrier liquid containing a divalent to tetravalent metal as a charge control agent. It is a developer.

In the present invention, the insulating carrier liquid is used as a liquid developer for electrophotography as a matter of course from the developing principle. And, as the insulating carrier liquid, specifically, a hydrocarbon such as hexane, a solvent known by the trade name of "ISOPER" manufactured by Esso Standard Oil Co., Ltd., silicone oil, vegetable oil, mineral oil, various synthetic oils. include electrically insulating liquid etc., preferably 10 ⁹
It is preferable to have an electric resistance of Ω · cm or more and a dielectric constant of 3.0 or less.

By the way, the role of the resin is mainly to fix the colorant to the material to be printed, and any resin having such a function may be used. Usually, a coloring agent called a flushing method or a water-containing paste of a coloring agent is put in a kneader called a flasher together with a resin solution or a resin and mixed, and then the resin solution or the resin is dried by kneading and dispersing the coloring agent at room temperature How to get rid of the solvent,
A method in which a resin and a colorant are melt-kneaded and then pulverized to form a resin for liquid developer combined with the colorant is used. Also, many known methods such as the dispersion polymerization method, which has been energetically studied by researchers of ICI, are known as the method for producing a resin for a liquid developer. Especially the dispersion polymerization method,
Since the production of fine particle polymers can be synthesized in an insulating liquid, it is also used in a method for producing a resin for a liquid developer (US Pat. No. 3,900,412). Regarding dispersion polymerization, Barrett's book, Dispersion Polymerizat
ion in Organic Media (1975) is well known. In order to obtain a high-resolution image, it is preferable that individual particles of the liquid developer are finer, and it is more preferable to utilize a dispersion polymerization method that can obtain submicron resin fine particles.

In the present invention, the role of the resin which is insoluble in the insulating carrier liquid is to fix the image after development and to retain the charge, and plays a great role in constituting the liquid developer. From the above-mentioned role, it is preferable that the minimum film forming temperature of the resin is equal to or lower than the fixing temperature, and the Tg of the resin is near the fixing temperature from the viewpoint of strength of the formed film. From such a point of view, as the resin which can be used in the present invention, an acrylic polymer or copolymer such as polymethylmethacrylate, a vinyl acetate resin such as a vinyl acetate resin or an ethylene-vinyl acetate resin or a copolymer is used. Examples thereof include polymers, styrene polymers or copolymers such as polystyrene, polyvinyltoluene and styrene-butadiene resins, and copolymers of nitrogen-containing monomers such as vinylpyrrolidone. Specifically, for example, methyl methacrylate, methyl acrylate, ethyl acrylate, propyl methacrylate, n-butyl methacrylate, iso-butyl methacrylate, vinyl acetate,
Vinyltoluene, styrene, p-chlorostyrene, divinylbenzene, diethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, dimethylaminoethyl methacrylate, acrylonitrile,
There are many resins such as vinylpyrrolidone, vinylpyridine, dimethylaminomethylmethacrylate and the like.

In view of the above-mentioned role, the resin particles formed of such an insoluble resin in the insulating carrier liquid can be used in terms of uniformization with the coloring agent and imparting high resolution. The diameter is preferably small, and the shape is preferably spherical in order to retain uniform electric charge. As a method for producing resin particles having a small particle size and a spherical shape, for example, a method such as emulsion polymerization can be adopted. The preferred method is the dispersion polymerization method. When the resin particles insoluble in the insulating carrier liquid are produced by this dispersion polymerization method, spherical resin particles cannot be obtained unless the soluble resin is present. It is necessary to use. As the resin soluble in the insulating carrier liquid used together for this purpose, a polymer or copolymer of an acrylic monomer is usually used because its polymerization is easy. Specifically, for example, lauryl methacrylate, lauryl acrylate, tridecyl methacrylate, tridecyl acrylate, stearyl methacrylate, stearyl acrylate, 2-ethylhexyl methacrylate, 2-ethylhexyl acrylate, hexyl methacrylate, octyl methacrylate, octyl acrylate, cetyl methacrylate, cetyl. Examples thereof include acrylate, vinyl laurate, vinyl stearate, nonyl methacrylate, nonyl acrylate, decyl methacrylate, cyclohexyl methacrylate and cyclohexyl acrylate. In order to produce resin particles by a dispersion polymerization method by combining a resin soluble in the insulating carrier liquid and a resin insoluble in the insulating carrier liquid, the resin soluble in the insulating carrier liquid is usually added to the insulating carrier liquid. Soluble in a solvent-insoluble polymer, after so-called graft polymerization, to form a solvent-insoluble resin particles by further polymerizing a monomer that becomes a solvent-insoluble polymer, or a monomer that becomes a resin soluble in the insulating carrier liquid There is a so-called one spot polymerization method in which a monomer that becomes an insoluble resin in the insulating carrier liquid and a monomer that becomes an insoluble resin are polymerized at the same time by utilizing a copolymerization rate ratio, and any method is the bullet. Introduced in the (Barret) book.

In the present invention, the particle size of the resin particles insoluble in the insulating carrier liquid is an important factor in relation to the colorant, and the constitution relating to this point is one of the important requirements in the present invention. ing. That is, the particle size of the resin particles is greatly involved in the integration with the colorant, and in the present invention, the ratio of fine particles having a particle size of 0.1 μm or less in the resin particles insoluble in the insulating carrier liquid is the resin particles. It is necessary to be 30% by volume or more of the whole, and preferably 50% by volume or more. As described above, when the proportion of the fine particles having a particle diameter of 0.1 μm or less is 30% by volume or more of the entire resin particles, the resin particles and the colorant particles are simultaneously fixed, and the colorant and the fixing resin consumed by the development are fixed. The ratio of the colorant and the fixing resin in the liquid developer is almost the same, and the composition in the liquid developer can always be kept constant, which is extremely stable, that is, has a long life. A liquid developer is obtained, and when it is 50% by volume or more, this action and effect are further improved.

In the present invention, the colorant must be formed by coating one or more colorants selected from pigments and dyes with a resin insoluble in the insulating carrier liquid. As the colorant used here, either a pigment or a dye can be used, but the pigment is mainly used due to its hue strength, and the dye is auxiliary used. However, in applications where an image is formed on cloth or the like by utilizing the sublimability of a dye, for example, in textile printing, only a dye is used as this colorant, and in this case, a disperse dye that is insoluble in an insulating carrier liquid. Sublimable dyes belonging to When the liquid developer of the present invention is prepared, this colorant is usually used after being pulverized into fine particles of about 0.1 to 3 μm. Examples of the colorant used in the present invention include many known colorants. Any pigment may be used as long as it exhibits a desired hue, for example, carbon black or
Examples include organic pigments such as insoluble azo pigments, soluble azo pigments, phthalocyanine pigments, isoindolinone pigments, quinacridone pigments, and perinone / perylene pigments. In addition, in combination with this pigment, for example, a dye categorized into a basic dye or an oil-soluble dye, which is modified so as to be soluble in an insulating carrier liquid, a modified solubilized insulating carrier liquid is used. It can also be used. The dye in this case does not need to be coated with a resin insoluble in the insulating carrier liquid, and exhibits a supplementary role for obtaining a desired hue and a supplementary function for imparting a charge for obtaining a desired charge.

As a method for coating the colorant with an insoluble resin in an insulating carrier liquid, various conventionally known methods can be mentioned, for example, an interfacial polymerization method, an in situ polymerization method, and a liquid method. Hardening coating method, phase separation method from aqueous solution, phase separation method from organic solution, in-liquid drying method, melt dispersion cooling method, powder bed method, air suspension coating method, electrostatic coalescence method, etc. are preferred. Is a method of treating in an insulating carrier liquid, and specifically, a resin insoluble in the carrier liquid is dispersed in the insulating carrier liquid and pulverized in the presence of a coloring agent, and the resin is simultaneously pulverized with the coloring agent. Coating method, a method of coating a colorant with a resin by a flushing method, a method of polymerizing a monomer that becomes an insoluble polymer in an insulating carrier liquid in the presence of a colorant, and coating the colorant with a resin. be able to.

The polarity of the colorant itself has a very large effect on imparting an electric charge, but by coating the colorant with a resin insoluble in the insulating carrier liquid, the polarity of the colorant becomes weaker, It makes it easy to give the desired charge,
In the present invention, a colorant formed by coating one or more selected from pigments and dyes with this insulative carrier liquid with an insoluble resin is used. By using in combination with the resin particles described above and an organic compound containing a divalent to tetravalent metal that is soluble in the insulating carrier liquid, the charge retention function is high, and the coloring agent particles are used even in the insulating carrier liquid. Since the electric charge is retained, even if a single-pass method is used in which the next electrostatic latent image is formed before the insulating carrier liquid is sufficiently dried, excellent developability is exhibited in color superimposition. The occurrence of image fogging and tailing can be prevented as much as possible. The cause of such action and effect has not been clarified at present, but the type of resin insoluble in the insulating carrier liquid,
Even if the type of the charge control agent is changed as long as it is an organic compound containing a metal having a valency of 2 to 4, which is soluble in the insulating carrier liquid, the same effect as the above can be obtained. Therefore, in the present invention, resin particles formed of a resin insoluble in the insulating carrier liquid and having a particle size of 0.1 μm or less occupies 30% by volume or more of the entire particles, and pigments and dyes are used. A charge control agent composed of a colorant particle formed by coating a selected colorant with an insoluble resin in an insulating carrier liquid, and an organic compound soluble in the insulating carrier liquid and containing a divalent to tetravalent metal. Is an essential condition, and a satisfactory image can be obtained especially when color superposition is performed by the single-pass method and the toner-on-toner method.

The organic compound containing a divalent to tetravalent metal that can be used as a charge control agent in the present invention includes Mn, Ca, Al, Zn, Zr, Cu, Fe and C in the compound.
Organic compounds containing metals such as r, Ba, Ce, Ni, Ti, Si, Sn, and Mg are applicable, and include, for example, metal naphthenates, metal octylates, lauric acid, myristic acid, palmitic acid, Fatty acid metal salts such as stearic acid and oleic acid, abietic acid metal salts, ethylenediaminetetraacetic acid metal complex salts, salts of the above metals such as alkylbenzene sulfonic acid metal salts, titanium coupling agents, silane coupling agents, etc. Can be mentioned. Further, a polymerizable organic metal compound such as a metal salt of acrylic acid, a metal salt of methacrylic acid, a metal salt of maleic acid, a metal salt of itaconic acid, a metal salt of fumaric acid, a metal salt of styrene sulfonic acid is used. It can also be used as a copolymerization component of the resin used in the present invention to impart a function as a charge control agent. Further, a dye soluble in the insulating carrier liquid may be used together for the purpose of increasing the electric charge.

[0016]

The present invention comprises a resin particle formed of a resin insoluble in the insulating carrier liquid and having a particle diameter of 0.1 μm or less occupying 30% by volume or more of the whole particle, and a pigment and a dye. A charge control agent composed of a colorant particle formed by coating a selected colorant with an insoluble resin in an insulating carrier liquid, and an organic compound soluble in the insulating carrier liquid and containing a divalent to tetravalent metal. By combining with, the charge retention ability is improved,
An image developed into an electrostatic latent image is stably retained even in the presence of an insulating carrier liquid, whereby an image with no image fog or tailing and good color superposition can be obtained.
Further, the resin particles and the colorant are integrally fixed, and the compositional change of the liquid developer is prevented as much as possible during the development, thereby improving the fixability to the printing medium and the liquid development. It is considered that the life of the agent is extended.

[0017]

EXAMPLES The present invention will be specifically described below based on Examples and Comparative Examples. In the following Examples and Comparative Examples, the particle size and particle size distribution were measured by a laser diffraction type particle size distribution measuring device.

[Preparation of Resin Solution] Preparation Example 1 Isopar G (trade name, manufactured by Esso Standard Oil Co., Ltd.) 1
To 00 parts by weight, 40 parts by weight of lauryl methacrylate (LMA) monomer and 60 parts by weight of vinyl acetate monomer were added, and further 1 part by weight of azobisisobutyronitrile (AIBN) as a polymerization catalyst was added to the above monomer, and nitrogen was added. Polymerization was performed in an atmosphere at 80 ° C. for 4 hours to prepare a 50% by weight resin solution. The average particle size of the resin particles insoluble in the obtained resin solution is 0.15 μm, and
Particles having a size of 0.1 μm or less were 31.5% by volume.

Preparation Example 2 50 parts by weight of LMA monomer and 50 parts by weight of vinyl acetate monomer were added to 100 parts by weight of Isopar G, and 1 part by weight of AIBN was added as a polymerization catalyst to the above monomers, and the mixture was heated to 80 ° C. under a nitrogen atmosphere. Was polymerized for 4 hours to prepare a 50% by weight resin solution. The average particle size of the resin particles insoluble in the obtained resin solution was 0.10 μm,
In addition, the particle size of 0.1 μm or less was 49.9% by volume.

Preparation Example 3 100 parts by weight of Isopar G were mixed with 40 parts by weight of 2-ethylhexyl methacrylate (2-EHMA) monomer and 60 parts by weight of vinyl acetate monomer, and AIBN was added to the above monomers as a polymerization catalyst at 80 ° C. under a nitrogen atmosphere. 1 weight part was added and polymerized for 4 hours to prepare a 50 weight% resin solution. The average particle size of the resin particles insoluble in the obtained resin solution was 0.10 μm or less, and the average particle size was 0.10 μm.
Particles of 1 μm or less were 63.9% by volume.

Preparation Example 4 2-EHMA monomer 5 was added to 100 parts by weight of Isopar G.
0 parts by weight and 50 parts by weight of vinyl acetate monomer were added, and further 1 part by weight of AIBN as a polymerization catalyst was added to the above monomers, and the mixture was polymerized at 80 ° C. for 4 hours in a nitrogen atmosphere.
A 0 wt% resin solution was prepared. The average particle size of the resin particles insoluble in the obtained resin solution was 0.10 μm or less, and the particles having a particle size of 0.1 μm or less accounted for 64.0% by volume.

[Preparation of Colorant Particle Dispersion] Preparation Example 5 Black colorant particles coated with 10% by weight of rosin were obtained by a flushing method using carbon black (carbon for color) as a black colorant. The colorant particles were dispersed in Isopar G and then pulverized by a wet pulverizer to prepare a colorant particle dispersion liquid containing 20% by weight of colorant particles having an average particle size of 0.3 μm.

Preparation Example 6 β-type copper phthalocyanine blue (PB.15.3) was used as a cyan colorant, and ester gum glycerin ester-modified maleic acid resin 10 was prepared by the flushing method.
Cyan colorant particles with weight percent coverage were obtained. The colorant particles were dispersed in Isopar G and then pulverized by a wet pulverizer to prepare a colorant particle dispersion liquid containing 20% by weight of colorant particles having an average particle size of 0.3 μm.

Preparation Example 7 Magenta colorant particles coated with 10% by weight of styrene-butadiene copolymer resin were obtained by a flushing method using a soluble azo-based Ca salt metal lake (PR 48.2) as a magenta colorant. It was The colorant particles are dispersed in Isopar G and then pulverized by a wet pulverizer to obtain an average particle size of 0.3.
A colorant particle dispersion containing 20% by weight of μm colorant particles was prepared.

Preparation Example 8 As a magenta colorant, dimethylquinacridone (P.
R. 122) was used to obtain magenta colorant particles coated with 10% by weight of vinyltoluene butadiene copolymer resin by a flushing method. The colorant particles are dispersed in Isopar G and then pulverized by a wet pulverizer to obtain an average particle size of 0.3 μm.
A colorant particle dispersion containing 20% by weight of m colorant particles was prepared.

Preparation Example 9 Yellow colorant particles coated with 10% by weight of rosin were obtained by a flushing method using insoluble disazo acetoacetic acid allylide (PY13) as a yellow colorant.
The colorant particles are dispersed in Isopar G and then pulverized by a wet pulverizer to obtain colorant particles 2 having an average particle size of 0.3 μm.
A colorant particle dispersion containing 0% by weight was prepared.

Preparation Example 10 Yellow colorant particles coated with 10% by weight of rosin were obtained by a flashing method using condensed azo acetoacetic acid allylide (PY95) as a yellow colorant. The colorant particles were dispersed in Isopar G and then pulverized by a wet pulverizer to prepare a colorant particle dispersion liquid containing 20% by weight of colorant particles having an average particle size of 0.3 μm.

Preparation Example 11 Using CI Disperse Black 30 as a black dye, black colorant particles coated with 5% by weight of rosin were obtained by a flashing method. The colorant particles are dispersed in Isopar G and then pulverized by a wet pulverizer to obtain an average particle size of 0.
A colorant particle dispersion containing 20% by weight of 8 μm colorant particles was prepared.

Preparation Example 12 Using CI Disperse Black 60 as a cyan dye, cyan colorant particles coated with 5% by weight of rosin were obtained by a flashing method. The colorant particles are dispersed in Isopar G and then pulverized by a wet pulverizer to obtain an average particle size of 0.8.
A colorant particle dispersion containing 20% by weight of μm colorant particles was prepared.

Preparation Example 13 Magnesium colorant particles coated with 5% by weight of rosin were obtained by a flashing method using CI Disperse Red 60 as a magenta dye. The colorant particles are dispersed in Isopar G and then pulverized by a wet pulverizer to obtain an average particle size of 0.
A colorant particle dispersion containing 20% by weight of 8 μm colorant particles was prepared.

Preparation Example 14 Using CI Disperse Yellow 76 as a yellow dye, yellow colorant particles coated with 5% by weight of rosin were obtained by a flashing method. The colorant particles are dispersed in Isopar G and then pulverized by a wet pulverizer to obtain an average particle size of 0.
A colorant particle dispersion containing 20% by weight of 8 μm colorant particles was prepared.

Example 1 Calcium abietic acid was used as the charge control agent, and the resin solutions of Preparation Examples 1 and 2 and the colorant particle dispersions of Preparation Examples 5, 6, 7 and 9 were combined to obtain a solid content concentration of 1% by weight. A liquid developer consisting of a% Isopar G solution was prepared. The respective composition ratios were 125 parts by weight of the colorant particle dispersion and 5 parts by weight of the charge control agent per 100 parts by weight of the resin solution. Using the obtained liquid developer, Nippon Steel Color Electrostatic Plotter X
Images were obtained at 2010. In each case, there was no image fogging or tailing, and good color superposition was exhibited. In addition, the toner is replenished from the concentrated liquid in proportion to the consumption of the developer, and 3
An image of 1,500 m was produced using a 6-inch wide gist. The ratio and charge of the resin particles and the colorant particles in the liquid developer after image formation were the same as before image formation.

Example 2 Calcium abietic acid was used as the charge control agent, and the resin solutions of Preparation Examples 3 to 4 and the colorant particle dispersions of Preparation Examples 5, 6, 8 and 10 were combined to obtain a solid content concentration of 1% by weight. %
A liquid developer was prepared from Isopar G solution. The respective composition ratios were 125 parts by weight of the colorant particle dispersion and 5 parts by weight of the charge control agent per 100 parts by weight of the resin solution. An image was obtained on a Nippon Steel color electrostatic plotter X2010 using the obtained liquid developer. In each case, there was no image fogging or tailing, and good color superposition was exhibited. Also, the toner is replenished from the concentrated liquid to meet the consumption of the developer,
An image of 1,500 m was produced using a 36-inch wide gist. The ratio and charge of the resin particles and the colorant particles of the liquid developer after image formation were the same as those before image formation.

Example 3 Aluminum stearate was used as the charge control agent, and the resin solutions of Preparation Examples 1 and 2 and the colorant particle dispersions of Preparation Examples 5, 6, 7 and 9 were combined in a solid content concentration of 1% by weight. %
A liquid developer was prepared from Isopar G solution. The respective composition ratios were 125 parts by weight of the colorant particle dispersion and 5 parts by weight of the charge control agent per 100 parts by weight of the resin solution. An image was obtained on a Nippon Steel color electrostatic plotter X2010 using the obtained liquid developer. In each case, there was no image fogging or tailing, and good color superposition was exhibited. Also, the toner is replenished from the concentrated liquid to meet the consumption of the developer,
An image of 1,500 m was produced using a 36-inch wide gist. The ratio and charge of the resin particles and the colorant particles of the liquid developer after image formation were almost the same as those before image formation.

Example 4 Tetraoctyl bis (ditridecyl phosphite) titanate was used as the charge control agent, and the resin solutions of Preparation Examples 3 to 4 and the colorant particle dispersions of Preparation Examples 5, 6, 8 and 10 were respectively prepared. In combination, a liquid developer comprising an Isopar G solution having a solid content concentration of 1% by weight was produced. The respective composition ratios were 125 parts by weight of the colorant particle dispersion and 5 parts by weight of the charge control agent per 100 parts by weight of the resin solution. An image was obtained on a Nippon Steel color electrostatic plotter X2010 using the obtained liquid developer. In each case, there was no image fogging or tailing, and good color superposition was exhibited. Further, the toner was replenished in accordance with the consumption of the developer from the concrete liquid, and an image of 1,500 m was formed using a 36-inch wide gist. The ratio and charge of the resin particles and the colorant particles of the liquid developer after image formation were the same as those before image formation.

Example 5 Using isopropyltriisostearoyl titanate as a charge control agent, the resin solutions of Preparation Examples 3 to 4 and Preparation Example 5,
A liquid developer comprising an Isopar G solution having a solid content concentration of 1% by weight was produced by respectively combining the colorant particle dispersion liquids of 6, 8 and 10. Each composition ratio is 125 parts by weight of the colorant particle dispersion liquid and 5 parts by weight of the charge control agent per 100 parts by weight of the resin solution.
It was part by weight. An image was obtained using a color electrostatic plotter 68444 manufactured by Calcomp, using the obtained liquid developer. In each case, there was no image fogging or tailing, and good color superposition was exhibited. Further, the toner was replenished in accordance with the consumption of the developer from the concrete liquid, and an image of 1,500 m was formed using a 36-inch wide gist. The ratio and charge of the resin particles and the colorant particles of the liquid developer after image formation were the same as those before image formation.

Example 6 Calcium abietic acid was used as the charge control agent, and the resin solutions of Preparation Examples 3 to 4 and the colorant particle dispersions of Preparation Examples 11 to 14 were combined to obtain Isopar G having a solid content concentration of 1% by weight. A liquid developer consisting of a solution was produced. Each composition ratio is such that 12 parts of the colorant particle dispersion liquid is 100 parts by weight of the resin solution.
5 parts by weight and 5 parts by weight of the charge control agent. Using the obtained liquid developer, Nippon Steel color electrostatic plotter X20
An image was obtained at 10. In each case, there was no image fogging or tailing, and good color superposition was exhibited. In addition, the toner is replenished from the concentrated liquid in proportion to the consumption of the developer,
An image of 1,500 m was produced using an inch-wide outline. The ratio and charge of the resin particles and the colorant particles of the liquid developer after image formation were the same as those before image formation.

[Preparation of Resin Solution] Preparation Example 15 100 parts by weight of Isopar G was added with 30 parts by weight of LMA monomer and 70 parts by weight of vinyl acetate monomer, and 1 part by weight of AIBN was added as a polymerization catalyst at 80 ° C. under a nitrogen atmosphere. And was polymerized for 4 hours to prepare a 50% by weight resin solution. The average particle size of the resin particles insoluble in the obtained resin solution was 0.20 μm, and
Particles having a size of 0.1 μm or less accounted for 12.2% by volume.

Preparation Example 16 2-EHMA monomer 20 in 100 parts by weight of Isopar G
1 part by weight of AIBN as a polymerization catalyst was added to the above monomer as a polymerization catalyst at 80 ° C. in a nitrogen atmosphere, and polymerization was carried out for 4 hours to prepare a 50% by weight resin solution. The average particle diameter of the resin particles insoluble in the obtained resin solution was 0.25 μm,
Further, the particles having a size of 0.1 μm or less was 5.4% by volume.

Preparation Example 17 100 parts by weight of Isopar G and 30 parts of 2-EHMA monomer
1 part by weight of AIBN as a polymerization catalyst was added to the above monomer as a polymerization catalyst at 80 ° C. in a nitrogen atmosphere, and polymerization was carried out for 4 hours to prepare a 50% by weight resin solution. The average particle size of the isopar-insoluble resin particles in the obtained resin solution was 0.17 μm, and the particles having a particle size of 0.1 μm or less was 26.2% by volume.

[Preparation of Colorant Particle Dispersion] Preparation Example 18 Carbon black (color carbon) was used as a black colorant, dispersed in Isopar G, and then pulverized by a wet pulverizer to give an average particle size of 0. 0.3 μm colorant particles 2
A colorant particle dispersion containing 0% by weight was prepared.

Preparation Example 19 β-type copper phthalocyanine blue (PB15.3) was used as a cyan colorant, dispersed in Isopar G, and then pulverized with a wet pulverizer to give an average particle diameter of 0. A colorant particle dispersion containing 20% by weight of 3 μm colorant particles was prepared.

Preparation Example 20 Soluble azo Ca salt metal lake (PR 48.2) was used as a magenta colorant, dispersed in Isopar G, and then pulverized by a wet pulverizer to obtain an average particle size. A colorant particle dispersion containing 20% by weight of 0.3 μm colorant particles was prepared.

Preparation Example 21 Insoluble disazo acetoacetic acid allylide (PY13) was used as a yellow colorant, dispersed in Isopar G, and then pulverized with a wet pulverizer to obtain an average particle diameter of 0.3 μm.
A colorant particle dispersion containing 20% by weight of m colorant particles was prepared.

Comparative Example 1 Calcium abietic acid was used as the charge control agent, and the resin solutions of Comparative Examples 15 to 17 and the colorant particle dispersions of Preparation Examples 5, 6, 7 and 9 were combined to obtain a solid content concentration of 1% by weight. A liquid developer consisting of a% Isopar G solution was prepared.
The respective composition ratios were 125 parts by weight of the colorant particle dispersion and 5 parts by weight of the charge control agent per 100 parts by weight of the resin solution. An image was obtained on a Nippon Steel color electrostatic plotter X2010 using the obtained liquid developer. In each case, a part of image fogging or tailing was observed, and good color superposition was insufficient in some areas. In addition, the toner is replenished from the concentrated liquid in proportion to the consumption of the developer, and 36-inch wide paper is used.
An image of 500 m was displayed. When the resins of Preparation Examples 15 and 16 were used, the image density was reduced from about 450 m when the image was produced, and when the resin of Preparation Example 17 was used, the image density was reduced from about 1000 m, and the resin of the liquid developer after image formation of 1500 m was obtained. As for the ratio of particles to colorant particles and the charge, the ratio of resin particles was higher than that before the image was formed, and the charge of the liquid developer was increased.

COMPARATIVE EXAMPLE 2 Aluminum stearate was used as a charge control agent, and the resin solutions of Comparative Examples 15 to 17 and the colorant particle dispersions of Comparative Examples 18 to 21 were respectively combined to produce Isopar G having a solid content concentration of 1% by weight. A liquid developer consisting of a solution was produced. The respective composition ratios were 125 parts by weight of the colorant particle dispersion and 5 parts by weight of the charge control agent per 100 parts by weight of the resin solution. Using the obtained liquid developer, Nippon Steel Color Electrostatic Plotter X
Images were obtained at 2010. In both cases, the occurrence of image fogging and tailing were partially observed, and there were some areas where good color superposition was insufficient. Further, toner was supplied from the conc liquid in proportion to the consumption of the developer, and an image of 1,500 m was formed using 36-inch wide paper. Preparation Examples 15 and 16
When using the resin of,
When the resin of Preparation Example 17 was used, the image density became low from about 800 m, and the ratio of the resin particles to the colorant particles and the charge of the liquid developer after image formation were higher than those before image formation. The resin particle ratio was high, and the charge of the developer was high.

Comparative Example 3 Tetraoctyl bis (ditridecyl phosphite) titanate was used as the charge control agent, and the resin solutions of Preparation Examples 15 to 17 and the colorant particle dispersions of Preparation Examples 18 to 21 were respectively combined to obtain a solid content. A liquid developer comprising an Isopar G solution having a concentration of 1% by weight was manufactured. Each composition ratio is the resin solution 1
The amount of the colorant particle dispersion was 125 parts by weight and the charge control agent was 5 parts by weight, based on 00 parts by weight. An image was obtained on a Nippon Steel color electrostatic plotter X2010 using the obtained liquid developer. In each case, the occurrence of image fog and trailing was observed, and the color overlay was also partially insufficient.

[0048]

According to the present invention, the charge retention ability is improved,
The developed image does not have fog or tailing, and an image with good color superimposition can be obtained. Moreover, the fixing property to the material to be printed is good, and the composition does not change even after repeated use. A liquid developer having a long life can be provided. For this reason,
The liquid developer of the present invention can exhibit excellent color superimposing properties even in single-pass development, and exhibits a long life.

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[Procedure amendment]

[Submission date] December 28, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0032

[Correction method] Change

[Correction content]

Example 1 Calcium abietic acid was used as the charge control agent, and the resin solutions of Preparation Examples 1 and 2 and the colorant particle dispersions of Preparation Examples 5, 6, 7 and 9 were combined to obtain a solid content concentration of 1% by weight. A liquid developer consisting of a% Isopar G solution was prepared. The respective composition ratios were 125 parts by weight of the colorant particle dispersion and 5 parts by weight of the charge control agent per 100 parts by weight of the resin solution. Using the obtained liquid developer, Nippon Steel Color Electrostatic Plotter X
Images were obtained at 2010. In each case, there was no image fogging or tailing, and good color superposition was exhibited. In addition, the toner is replenished from the concentrated liquid in proportion to the consumption of the developer, and 3
An image of 1,500 m was printed using a 6-inch wide paper . The ratio and charge of the resin particles and the colorant particles in the liquid developer after image formation were the same as before image formation.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0033

[Correction method] Change

[Correction content]

Example 2 Calcium abietic acid was used as the charge control agent, and the resin solutions of Preparation Examples 3 to 4 and the colorant particle dispersions of Preparation Examples 5, 6, 8 and 10 were combined to obtain a solid content concentration of 1% by weight. %
A liquid developer was prepared from Isopar G solution. The respective composition ratios were 125 parts by weight of the colorant particle dispersion and 5 parts by weight of the charge control agent per 100 parts by weight of the resin solution. An image was obtained on a Nippon Steel color electrostatic plotter X2010 using the obtained liquid developer. In each case, there was no image fogging or tailing, and good color superposition was exhibited. Also, the toner is replenished from the concentrated liquid to meet the consumption of the developer,
An image of 1,500 m was printed using 36-inch wide paper . The ratio and charge of the resin particles and the colorant particles of the liquid developer after image formation were the same as those before image formation.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0034

[Correction method] Change

[Correction content]

Example 3 Aluminum stearate was used as the charge control agent, and the resin solutions of Preparation Examples 1 and 2 and the colorant particle dispersions of Preparation Examples 5, 6, 7 and 9 were combined in a solid content concentration of 1% by weight. %
A liquid developer was prepared from Isopar G solution. The respective composition ratios were 125 parts by weight of the colorant particle dispersion and 5 parts by weight of the charge control agent per 100 parts by weight of the resin solution. An image was obtained on a Nippon Steel color electrostatic plotter X2010 using the obtained liquid developer. In each case, there was no image fogging or tailing, and good color superposition was exhibited. Also, the toner is replenished from the concentrated liquid to meet the consumption of the developer,
An image of 1,500 m was printed using 36-inch wide paper . The ratio and charge of the resin particles and the colorant particles of the liquid developer after image formation were almost the same as those before image formation.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0035

[Correction method] Change

[Correction content]

Example 4 Tetraoctyl bis (ditridecyl phosphite) titanate was used as the charge control agent, and the resin solutions of Preparation Examples 3 to 4 and the colorant particle dispersions of Preparation Examples 5, 6, 8 and 10 were respectively prepared. In combination, a liquid developer comprising an Isopar G solution having a solid content concentration of 1% by weight was produced. The respective composition ratios were 125 parts by weight of the colorant particle dispersion and 5 parts by weight of the charge control agent per 100 parts by weight of the resin solution. An image was obtained on a Nippon Steel color electrostatic plotter X2010 using the obtained liquid developer. In each case, there was no image fogging or tailing, and good color superposition was exhibited. In addition, the toner is replenished from the conc .
An image of 1,500 m was printed using paper . The ratio and charge of the resin particles and the colorant particles of the liquid developer after image formation were the same as those before image formation.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0036

[Correction method] Change

[Correction content]

Example 5 Using isopropyltriisostearoyl titanate as a charge control agent, the resin solutions of Preparation Examples 3 to 4 and Preparation Example 5,
A liquid developer comprising an Isopar G solution having a solid content concentration of 1% by weight was produced by respectively combining the colorant particle dispersion liquids of 6, 8 and 10. Each composition ratio is 125 parts by weight of the colorant particle dispersion liquid and 5 parts by weight of the charge control agent per 100 parts by weight of the resin solution.
It was part by weight. An image was obtained using a color electrostatic plotter 68444 manufactured by Calcomp, using the obtained liquid developer. In each case, there was no image fogging or tailing, and good color superposition was exhibited. Further, toner was supplied from the conc liquid in proportion to the consumption of the developer, and an image of 1,500 m was formed using 36-inch wide paper . The ratio and charge of the resin particles and the colorant particles of the liquid developer after image formation were the same as those before image formation.

[Procedure correction 6]

[Document name to be amended] Statement

[Name of item to be corrected] 0037

[Correction method] Change

[Correction content]

Example 6 Calcium abietic acid was used as the charge control agent, and the resin solutions of Preparation Examples 3 to 4 and the colorant particle dispersions of Preparation Examples 11 to 14 were combined to obtain Isopar G having a solid content concentration of 1% by weight. A liquid developer consisting of a solution was produced. Each composition ratio is such that 12 parts of the colorant particle dispersion liquid is 100 parts by weight of the resin solution.
5 parts by weight and 5 parts by weight of the charge control agent. Using the obtained liquid developer, Nippon Steel color electrostatic plotter X20
An image was obtained at 10. In each case, there was no image fogging or tailing, and good color superposition was exhibited. In addition, the toner is replenished from the concentrated liquid in proportion to the consumption of the developer,
An image of 1,500 m was printed using inch-width paper . The ratio and charge of the resin particles and the colorant particles of the liquid developer after image formation were the same as those before image formation.

Claims (2)

[Claims] 1. A liquid developer for electrophotography, comprising a toner mainly composed of a resin and a colorant dispersed in an insulating carrier liquid, wherein the resin is one or more resin particles insoluble in the insulating carrier liquid. At least 0.1 μm in size, and the particles having a particle size of 0.1 μm or less occupy 30% by volume or more of the entire resin particles, and the colorant is one or more selected from pigments and dyes and is insoluble in the insulating carrier liquid. And a liquid developer for electrophotography, comprising an organic compound soluble in the insulating carrier liquid containing a divalent to tetravalent metal as a charge control agent. 2. The liquid developer for electrophotography according to claim 1, which is used for single-pass development.