JPS63178258A - Liquid developer for electrostatic photography - Google Patents

Abstract

PURPOSE:To obtain a liq. developer having a long shelf life, superior stability and fixability and providing especially high image quality by using dispersible resin obtd. by polymerizing three kinds of specified monomers in the presence of a specified polymer as resin to be dispersed in a highly insulating hydrocarbon medium. CONSTITUTION:When resin particles are dispersed in a highly insulating hydrocarbon medium to obtain a liq. developer for electrostatic photography, dispersible resin obtd. by polymerizing a monomer which is soluble in the medium and is made insoluble by polymn., a monomer which is soluble in the medium and forms a soluble polymer, and a monomer having two or more polymerizable unsatd. double bonds in the presence of a polymer which is insoluble in the medium and has carboxy, hydroxyl or amido groups is used as the resin. A liq. developer giving a clear image with no blurry ghost ground the image and hardly causing the deterioration of image quality even after continuous use for a long period is obtd.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a liquid developer for developing electrostatic latent images in electrophotography, electrostatic recording, etc., and has excellent storage stability, stability, and fixing properties. In particular, the present invention relates to a liquid developer that can achieve high image quality.

(Prior Art) Many types of electrostatic latent image liquid developer are already known. For example, colorant pigments or dyes such as carbon black, cyanine blue, nigrosine, and oil dyes are placed in a highly insulating medium together with resins such as rosin, alkyd resins, acrylic resins, and synthetic rubbers, and mechanically processed using a ball mill, attritor, homogenizer, etc. The most common method was to disperse particles in the dispersion and further add metal soap, amines, higher fatty acids, etc. to stably impart an electric charge to the dispersed particles of the dispersion.

However, since the liquid developer prepared by this method has a large particle size distribution of dispersed particles as a developer, it generates a lot of precipitates and has poor charge stability and manufacturing stability, making it difficult to obtain stable images. It had the disadvantage of being difficult.

As described in Japanese Patent Publications Nos. 53-54029 and 57-12985, a vinyl group that can be polymerized by a polymer reaction is introduced into a precursor polymer in advance, and monomers are polymerized in the presence of this group to form a graft. There is a method of obtaining a liquid developer by producing a copolymer and coloring it with a dye.

Although this method can be said to be an excellent method, there are problems in the control and reproducibility of the introduction of vinyl groups, often accompanied by the formation of gels, and in some cases it is difficult to form dispersed particles stably.
Coarse particles with a size of 1 or more layers or fine particles with a size of 0.1 μ or less may be generated, which is not preferred in practice.

Furthermore, JP-A-59-83174 and JP-A-59-177572
No. 59-212850@, No. 59-212851, No. 60-164757M, No. 60-179751,
60-” No. 185962, No. 60-185963,
No. 60-252367, No. 61-116364, No. 61-116365, etc. are soluble in a highly insulating medium in the presence of a soluble polymer, but become insoluble when a polymer is formed. It is described that monomers are polymerized and the resulting resin dispersion is used as a liquid developer.

This method has excellent industrial production stability and dispersion stability. However, when a liquid developer using a resin obtained by this method is used to form an image on an electrostatic recording material using Coulomb force, electrostatic mutual repulsion due to the Coulomb force of the dispersed particles themselves and the concentration of the dispersion stabilizing polymer occur. A volume exclusion effect occurs in which the particles rise and repel each other. For this reason, when the effective surface potential of the electrostatic recording material decreases, it has the disadvantage that a blur-like ghost is likely to occur around the image. Furthermore, if a liquid developer using a resin obtained by this method is used continuously while being actually replenished, the solvent-soluble resin will accumulate, and depending on the type of soluble resin used, it will affect the N carrier of the dispersed particles. It also had the disadvantage of giving

Further, in order to use the developer as a developer for a printing plate in which a toner image functions as a resist layer as described below, it is desirable that the toner particles be internally crosslinked. This is because a resist layer formed by fixing and forming particles having a crosslinked structure has high resistivity, and a good printing plate can be prepared. No conventional wet type developer has satisfied all of these necessary properties.

(Objective of the Invention) The object of the present invention is to provide a liquid developer which improves the conventional drawbacks mentioned above, and which provides a clear image with no bleeding ghost in the image periphery, and which has a long lifespan. It is an object of the present invention to provide a liquid developer that exhibits little image deterioration even when used continuously for many years.

Another object of the present invention is to provide a liquid developer that provides excellent printing quality as a developer for offset lithographic printing plates using zinc oxide or organic semiconductors as photoreceptors.

Another object of the present invention is to provide a liquid developer for printing plates that has an internal crosslinking structure and exhibits strong resistivity, especially against eluents with high permeability such as benzyl alcohol and butyl diglycol.

(Structure of the Invention) The present invention relates to an electrostatographic developer containing at least resin particles dispersed in a highly insulating hydrocarbon medium.

In this case, the resin is combined with the following polymer (A>) and monomer (8) and monomer (C) in the presence of the following polymer (S).
) is a resin dispersion obtained by polymerizing a liquid developer for electrostatic photography.

Polymer (S): A polymer that is insoluble in the medium and has a carboxyl group, water Im, or amide group.

Monomer (A): A monomer that is soluble in the medium and becomes insolubilized by polymerization. Monomer (B): A monomer that is soluble in the medium and forms a soluble polymer upon polymerization.

Monomer (C) Monomer having two or more unsaturated double bonds capable of polymerization 0 The highly insulating hydrocarbon medium used in the present invention is normal paraffin hydrocarbon, isoparaffin hydrocarbon, alicyclic hydrocarbon, halogen Examples include aliphatic hydrocarbons, but from the standpoint of safety and volatility, practically preferred isoparaffinic hydrocarbon solvents such as Shell Silua 1 (manufactured by Shell Oil Co., Ltd.), Isopar 0, Isovert t, and Isopar 1. , Isopar G (Isopar is a product name of Exxon) and Ivy Solvent (manufactured by Idemitsu Petrochemical)
etc. can be used.

The structure of the resin used in the liquid developer of the present invention and the formation mechanism of the resin dispersion (hereinafter referred to as emulsion) will be explained. The polymer (S) used in the present invention that is insoluble in the solvent and has a carboxyl group, a hydroxyl group, or an amide group is referred to as a shell polymer. In addition, a monomer (A>) which is soluble in the solvent and becomes insolubilized when polymerized is the P1 polymer, and a monomer (
Let the polymer of B) be P2 polymer. The most common embodiment of the emulsion used in the present invention before the start of polymerization is the solvent, shell polymer, monomer (A> and monomer (B).
) and monomer (C) are mixed together. (
In order to control the physical properties such as 1'-m1TO of the obtained emulsion particles, each material may be added with 2
(More than one species may be used) Furthermore, in order to control heat generation during polymerization, the monomer used may be divided and added later.

The formation mechanism of emulsion particles can be broadly classified into two types. The first case is that the state before the start of the polymerization is homogeneous. In this case, the fact that the shell polymer becomes homogeneous even though it is originally insoluble in the solvent is because it dissolves in the monomer (A>) or the monomer (B).

By heating the aqueous system and adding a polymerization initiator, radicals are generated and polymerization starts. Since the P1 polymer component produced from the monomer (A) is insoluble in the solvent, the P2 polymer component soluble in the solvent is used as a protective colloid to form particles and become cloudy to produce an emulsion.

As the polymerization progresses, the shell polymer cannot be uniformly dissolved in the system because the monomer to be solubilized is consumed as a polymer. Therefore, it becomes insolubilized, but actually it is deposited on the surface of the emulsion particles formed by the P1 polymer.

Monomers having two or more polymerizable unsaturated double bonds (
When C) is added all at once before polymerization, the entire polymerization system often gels. In such a case, when emulsion particles are formed and cloudiness begins, monomer (C) is gradually added dropwise to form particles that form an internal crosslinked structure. Chestnut degree depends on the type and type of monomer (C). Also, monomer (C) and monomer (A>
The copolymerization reactivity ratio with (B) and (B) is also an important factor determining the degree of crosslinking.

The sedimentation stability of the emulsion and the particle size also depend on the type of shell polymer (2); if there is too much shell polymer, sedimentation tends to occur. However, in this case, dispersion stability can be improved by increasing the amount of monomer (B).

As mentioned above, the amount of shell polymer depends on the type and amount of monomer (A) and monomer (B) and the type of shell polymer, but it is 1% to 50% (by weight) of monomer (A>), preferably 3%. ~25% is preferred.

The particle size is determined by the amount of P2 polymer component, i.e. the charged monomer (
B) It can be changed relatively freely by ffi. The monomer (A)/monomer (B) ratio depends, of course, on the solubility and cohesiveness of the resulting polymer in the solvent, but a relatively stable emulsion can be obtained in the weight range of 98/2 to 20/80. However, a range of about 95/5 to 50/50 is suitable.

Furthermore, since the particle size most depends on the solubility parameters of the solvent and the polymer to be produced, the particle size can be controlled by selecting these factors.

Thus, the formed emulsion particles have a cross-linked core layer consisting mainly of P1 polymer inside, a shell layer consisting of a shell polymer deposited on the outside, and a main layer stabilizing the particles in the solvent at the outermost layer. It is thought that an internally crosslinked three-layer structure of a dispersed layer made of P2 polymer is formed. Of course, as can be seen from the particle formation mechanism, there are no clear interfaces between the layers, and it is presumed that each component is more localized in a three-layered state.

The degree of crosslinking of the emulsion particles affects the constant V temperature of the developed toner image. That is, in the case of particles having a high-density crosslinked structure, the constant @ temperature becomes high, which causes a practical problem. Although it depends on the type of monomer (C), monomer (A
>0.1 to 20 weight percent, preferably 0
．． 5-5% is a suitable amount.

In addition, an internally crosslinked type is preferable for dispersion stabilization.

That is, the monomer (
A good emulsion can be obtained by selecting a monomer (C) that is easy to copolymerize with A> and has a poor copolymerization with the monomer (B) that is soluble in the solvent even if a polymer is formed.

The second formation mechanism of emulsion particles is a case where the state before the start of polymerization is heterogeneous. In this case, the polymerization may be started as is, but it is preferable to add an auxiliary solvent having a relatively low boiling point to make the system homogeneous. When polymerization is started in the same way as in the first formation mechanism, the P2 polymer component is treated with a protective colloid to form a cloudy emulsion mainly composed of the P1 polymer component. If the auxiliary solvent is distilled off after the polymerization is completed, the shell polymer will be deposited on the surface of the emulsion particles. If too much co-solvent is required, a uniform emulsion may not be produced.

Examples of the auxiliary solvent include tetrahydrofuran, ethyl alcohol, -isopropyl alcohol, methyl ethyl ketone, and ethyl acetate.

The shell polymer used in the present invention must have carboxyl or hydroxyl or amide groups and be insoluble in the highly insulating hydrocarbon medium. Furthermore, since it is desirable that the monomer that becomes insolubilized in the solvent upon polymerization has soluble properties, copolymers with various compositions can be selected depending on the monomer (A> or monomer (B)) used. An embodiment of the emulsion is that the shell polymer is localized on the surface of the resulting emulsion particles.

Another way to look at it is to modify the particle surface with a polymer having a carboxyl group, a hydroxyl group, or an amide group.

Shell polymers that exhibit these properties, namely,
It is desirable that the heptamer component constituting the polymer (S) used in the present invention contains, for example, a monomer of general formula (I).

General formula CI) (R1 and R2 are H1 alkyl group, -COOR4, -CH
2COOR5, and R3, R4 and R5 represent an aliphatic group which may have a substituent. ) The monomer represented by the general formula (I) is an esterified product of an unsaturated carboxylic acid such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, etc. If it is an ester of an aliphatic group, for example, methyl or ethyl , propyl, butyl, amyl, hexyl, ethylhexyl, dodecyl, tridecyl, hexadecyl, docosanyl, hexadecenyl, oleyl, and the like. These may be substituted with halogen atoms, amino groups, alkoxy groups, etc., or may be bonded with nitrogen, oxygen, sulfur, etc. atoms.

Among the monomer components constituting the polymer (S), monomers having a carboxyl group include, for example, general formula (II)
It is expressed as

General formula (I [) CH21=CZ2-COOt-1 (Zl, Z2 is 1, methyl group, -CH2C0OH, -
Represents a COOH group. ) Examples of the monomer represented by the general formula (n) include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, and fumaric acid.

Among the heptamer components constituting the polymer (S), monomers having a hydroxyl group include, for example, the general formula % general formula (III) 1 Y2 CH=C-CO2-A-OH Yl, Yl is H or methyl The group A represents an optionally substituted hydrocarbon group, oxyethylene group, or oxypropylene group. ) The monomer represented by the general formula (I[I) is an esterified product of an unsaturated carboxylic acid such as acrylic acid, methacrylic acid, or crotonic acid, and has a hydroxyl group. For example, hydroxymethyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate,
Hydroxyoctyl methacrylate, hydroxymethyl acrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyoctyl acrylate, polyethylene glycol methacrylate,
Examples include polyethylene glycol acrylate, polypropylene glycol methacrylate, polypropylene glycol acrylate, hydroxyedyl crotonate, and the like. Alternatively, hydrogen atoms may be replaced with halogens.

Among the monomer components constituting the polymer (S), the monomer having an amide group is, for example, the general formula % formula % general formula (IV) CM Ql = CQz -CON R1Rz (Ql
, Q2 represents H or an alkyl group, and R1 and R2 represent an aliphatic group which may have a substituent.

Examples of the monomer represented by the general formula (IV) include acrylamide, methacrylamide, N-isopropylacrylamide, N-tert-butylacrylamide,
Examples include N,N-dimethylacrylamide and the like. Furthermore, as monomers having an amide group, acrylpiperidine, acrylmorpholine, acrylpyrrolidine, phenylmethacrylamide, N-anisylmethacrylamide, N-tolylmethacrylamide, N-chlorophenylacrylamide, N-nitrophenylmethacrylamide 1, N -Methacryl-α-aminoketone, N-methylolmethacrylamide and its esters, N-
Examples include β-cyanoethyl methacrylamide and diacetone acrylamide.

Monomers constituting these hand coalescing (S), ie shell polymers, have been exemplified, but since it is important for shell polymers to have a carboxyl group, hydroxyl group or amide group, the monomers that can be used are of the general formula (I ), (II
), (III), and (IV). For example, monomers listed in "Synthetic Polymers" (published by Asakura Shoten), "Kyomunshi Data Handbook" (published by Baifukan), etc. can also be used.

Further, in order to adjust the physical properties of the shell polymer, a copolymerizable monomer may be copolymerized as the third component, or a plurality of the above-mentioned polymers may be combined.

Furthermore, a plurality of polymers may be used as the shell polymer.

Shell polymers can be obtained by known polymerization methods, but in order to synthesize emulsions using shell polymers as raw materials, it is best to obtain them by solution polymerization in a solvent that is the same as or mixes well with the solvent used during emulsion synthesis. preferable. Furthermore, it is not very desirable that the shell polymer has the property of being dissolved in the solvent at high temperatures.

This is because the properties of the liquid developer depend on temperature, and particularly when the temperature rises, there is a risk that the shell polymer will be desorbed from the particles and change the physical properties of the toner particles.

Examples of copolymers of the shell polymer used in the present invention will be listed below, but the present invention is not limited thereto. The numbers in parentheses are the gravity ω ratios.

(1) n-hexyl methacrylate-1--methacrylic acid (94/6) (2) Acrylic acrylate-acrylic acid (3) Stearyl methacrylate-methacrylic acid (88/12) (4) Stearyl Methacrylate-vinyl acetate-crotonic acid (90/8/2> (5) cyclohexyl methacrylate-methacrylic acid (9515> (6) lauryl acrylate-vinyl acetate-mylene anhydride r1i (92/6/2> (7) Acryl acrylate methacrylate - methacrylic acid (4515015) (8) n-hexyl methacrylate - hydroxyethyl methacrylate (93/7) (9) 2-ethylhexyl methacrylate - hydroxyethyl acrylate (9515) )(
10) n-butyl acrylate lauryl methacrylate hydroxyethyl acrylate (40157/3> (11) stearyl methacrylate - hydroxyisopropyl methacrylate (12) ethyl methacrylate - lauryl acrylate - hydroxyethyl acrylate (10/8515> (13) ) Vinyl acetate-n-hexyl methacrylate-hydroxypropyl methacrylate (10/8
7/3) (14) Cyclohexyl methacrylate-hydroxyethyl acrylate (92/8) (15) n-hexyl methacrylate-acrylamide (96/4') (16) Stearyl methacrylate-methacrylamide (9515) ( 17) Stearyl methacrylate-N,N-dimethylacrylamide (90/10) 1B) Lauryl methacrylate-phenylacrylamide (9515) (19) n-hexyl acrylate-diacetone acrylamide (92/8) (20) Stearyl Methacrylate-1 to -N-isopropylacrylamide (85/15) A monomer used in the present invention that provides a polymer that is soluble in the solvent and becomes insolubilized when polymerized (A> is, for example, vinyl such as acetic acid, propionic acid, acetic acid, etc.) Esters Yaaryl esters. Alkyl esters such as itaconic acid, maleic acid, crotonic acid (however, polymers of long chain alkyl are solubilized, so up to 4 carbon atoms), and further substitution of acrylic acid and methacrylic acid. Lower alkyl esters and amides that may have groups.

Examples include styrene derivatives such as styrene, methylstyrene, and vinyltoluene, and those having a heterocycle such as N-vinylpyrrolidone and N-vinyloxazolidone. In order to adjust the physical properties of the obtained emulsion particles, a copolymerizable secondary monomer such as a basic monomer or a heptamer having an ether bond is used.
The components may be copolymerized.

The monomer (B) used in the present invention that gives a polymer that is soluble in the solvent and soluble even when polymerized is, for example, the following general formula (V).
It is indicated by.

General formula (V) In general formula (V), R represents an aliphatic group having 8 or more carbon atoms, and B
represents an ester group or an amide group, T1 and T2 represent a hydrogen atom, an alkyl group, -GOOR'', CH2GOOR''.

R'R'' represents an aliphatic group.

Examples of the monomer (8) include esters and amides of acrylic acid, methacrylic acid, crotonic acid, maleic acid, and itaconic acid; for example, in the case of aliphatic groups, decyl, dodecyl, tridecyl, hequinadecyl, docosanyl,
Examples include hexadecenyl and oleyl.

These may be substituted with a halogen atom, an amine group, an alkoxy group, a hydroxy group, etc., or may be bonded with atoms such as nitrogen, oxygen, sulfur, etc.

The necessary properties of the monomers (A) and (B) are that, although it is preferable that each monomer dissolves the shell polymer, it is not necessary that each monomer dissolve the shell polymer;
There is no problem if the shell polymer, monomers (A) and (B) are mixed to form a substantially homogeneous system. If the solubility is poor and a heterogeneous system is formed, an auxiliary solvent with a relatively low boiling point may be used and distilled off after the polymerization is completed.

The monomer (C) having two or more polymerizable unsaturated double viscosity molecules used in the present invention has, for example, two or more vinyl groups or allyl groups in the molecule, and monomer (A> or monomer (B ) and forms a crosslinked structure.These monomers having two or more polymerizable unsaturated double bonds are generally well known, and include, for example, the following monomers.

(a) (b) CH=C1(.

(C) CIl□=C[1 0COCII2CH20COC1l=CH2 (d> C112=Ctl OCO4CH□'') τ0COCH=CH2 (e) C1,=CH COO4CH2Ti1-OCOiC) I2ヰC00CH
=C1l.

(F) CIL □ -c [I C0NIHCH # RCOOCIL = CIL □ (H) (I> COO + CH # R 0ch = CHZ (J> CI + 2 = CC113 CC113 CC113 COOCH2CH200CC = CH2 (K) CH2 (K) CH2 (K) CIL □ -CHC112ON And "Synthetic polymer" (published by Asaji Shoten), [Polymer Data Handbook] (published by Baifukan), etc., polyfunctional monomers can also be used.
No. 549, No. 59-114550, No. 60-1859
No. 62, No. 60-185963, No. 60-249”1
No. 56, No. 60-249158, No. 60-25002
0@, No. 60-252367, No. 60-254055
No. 60-262174, No. 6'l-60713, No. 6'l-6'1171, No. 60-112161, No. 60-164757, No. 61-209460,
Monomers listed in No. 61-217069 and the like can also be used, and the monomers are not limited to the above monomers.

In order to use the emulsion obtained in the present invention as a liquid developer for electrostatic photography, the dispersed resin particles may be colored and charged. As the colorant for the dispersed particles, any colorant generally known as a colorant for liquid developers can be used. For example, oil-soluble dyes such as oil black and oil red, basic azo dyes such as Bismarck brown and chrysoidine, wool black, amide black green, and blue black H.
Acidic azo dyes such as F, direct dyes such as Congo red, anthraquinone dyes such as Sudan violet and acid blue, carbonium dyes such as auramine, malachite green, crystal violet, and Victoria blue, rhodamine dyes such as Rhodamine B, safranin,
Examples include dyes such as quinone imine dyes such as nigrosine and methylene blue. As a pigment, carbon black,
Examples include phthalocyanine blue, phthalocyanine green, washing red, and benzidine yellow.

Also, surface-treated pigments such as carbon black dyed with nigrosine, kraft carbon, silicon oxide fine powder dyed with rhodamine H, microlith blue, etc. can be used.

The simplest method for coloring the dispersed particles is to dissolve the colorant to be used in advance in a solvent, and then dropwise add and stir this colorant solution into the emulsion. In particular, coloring can be achieved well by dissolving the oil dye in an aromatic solvent such as toluene or xylene and adding it dropwise with stirring. Since the used solvent is mixed with the toner solvent, there is no need to remove it unless there is an adverse effect on quality. Alternatively, the solvent may be removed later by using a solvent system as disclosed in JP-A-57-48738.

Furthermore, as another coloring method, the coloring may be removed by adding the jq radish emulsion and the coloring agent to a dispersing machine such as a colloid mill, a ball mill, or a vibration mill and applying mechanical vibration.

With the liquid developer of the present invention, by selecting a charge control agent, a colorant, etc., it is possible to freely produce a toner having a positive charge or a j-toner having a negative charge.

The charge control agent used in the liquid developer of the present invention includes:
For example, copper oleate, cobalt naphthenate, sulfur naphthenate, manganese naphthenate, cobal 1-octylate, lecithin, sodium dioctyl sulfosuccinate, aluminum salt of sudebellite resin, etc. may be mentioned.

Also, Special Publication No. 49-26594, No. 49-26595
No., JP-A-60-'I 73558, JP-A No. 60-175
No. 060, No. 60-179750, No. 6C)-18?
No. 147, No. 60-218662, Patent Application No. 60-78
Charge control agents listed in No. 062 and the like can also be used.

The liquid developer obtained by the present invention is disclosed in Japanese Patent Publication No. 37-17162.
No. 38-6961, No. 41-2426, No. 46
-39405, JP 50-19509 @, JP 50-
No. 19510, No. 54-145538, No. 54-89
No. 801, No. 54-134632, No. 54-1980
No. 3, No. 55-105244, No. 57-161863
No. 58-76843, No. 58-76844, No. 58-'I22897, No. 5B-'118658,
No. 59-170862, No. 60-194467, No. 61-32861, No. 61-49895, No. 6'l
It can also be used for lithographic printing plates such as those described in No. 67869 and No. 61-149399@. When used for these lithographic printing plates, it must have resistivity to alkaline eluents. In the case of the liquid developer obtained according to the invention, it consists of particles internally crosslinked by the monomer (C), and the toner formed has strong alkali resistance.

We can handle all types of alkaline eluents, including weakly alkaline types based on amino alcohols, strong alkaline types using inorganic alkalis such as sodium hydroxide and potassium hydroxide, and those using penetrating agents such as benzyl alcohol. Liquid developers can be provided and give good printing plates.

Synthesis Example 1 (Synthesis of emulsion of the present invention) 40% of n-hexyl methacrylate-methacrylic acid copolymer (exemplary shell polymer (1) of the present invention) was prepared by a known solution polymerization method.
% xylene solution was obtained.

When this solution 353 was added to 11 hexane, a copolymer precipitate was obtained in the form of a slurry.

The slurry was washed and decanted several times with Hexazi,
1β equipped with NZ gas inlet pipe, thermometer, stirrer, and cooling pipe
4309 IP Solvent (manufactured by Idemitsu Petrochemical Co., Ltd.) was added to 7 J [l] of 4309.

At this stage, even if well stirred, the copolymer remains precipitated without being dissolved in the IP solvent at all.

Next, 136 g of vinyl acetate (corresponding to monomer (A)),
After adding 30 g of lauryl methacrylate (corresponding to monomer (B)) and stirring well, a uniform transparent solution was obtained. After purging with N2 gas at 80°C, 1 g of azobisisobutyronitrile (AIBN) was added as a polymerization initiator, and polymerization started, and after about 50 minutes, it started to become cloudy. At this stage, 4.1 g of divinyl adipate ( Gradually, dropwise addition of 20 g of a xylene solution in which a monomer (equivalent to monomer) was dissolved was started. Approximately 2
Although the dropping was completed in 0 minutes, the internal temperature rose to 118°C.

After the internal temperature had decreased to 80'C, heating was continued for an additional 2 hours. In order to remove the remaining vinyl acetate monomer, the inside of the reactor was distilled under reduced pressure to obtain about 25 g of distillate. The resulting white emulsion had no precipitates and almost no monomer odor. When the particle size was measured using an electron microscope, the particle size was 0.23μ, and there were almost no particle size valves 15.

Synthesis Examples 2 to 13 Emulsions with the compositions shown in the table below were synthesized by the same method as in Synthesis Example 1. Shell polymer is abbreviated as S.
The amount is expressed as solid content.

Monomer (A), monomer (B), and monomer (C) are abbreviated as A, B, and C, respectively. Furthermore, Synthesis Example 3.9.1
For 2, 20 g of methyl ethyl ketone as a co-solvent.
It was used.

(The following is a blank space) The emulsion obtained in this example had almost no precipitates and was stable without increasing the amount of precipitates even after being stored naturally for several months. The particle size of the emulsion is 1 under an electron microscope! As a result of measuring from the shadow, it was found to be about 0.15 to 0.3μ, although it differs depending on the type of emulsion. However, each emulsion showed an almost monodisperse particle size distribution, and no coarse particles or fine particles were observed, and the particle sizes were extremely uniform.

Comparative Synthesis Examples 1 to 3 Emulsions were obtained in exactly the same manner as Synthesis Example 1.5.10 except that the monomer (C) was added dropwise. (Comparative emulsions 1 to 3). These emulsions also did not generate any precipitates and were stable emulsions.

The emulsion obtained here consists of particles without an internal crosslinked structure.

Comparative Synthesis Example 4 A stearyl methacrylate-methacrylic acid copolymer (40% hexane with a weight ratio of 98/2) solution was obtained by a known solution polymerization method. This polymer solution 709 was mixed with 4503 I
When added to a 4-tube flask together with P solvent in the same manner as in Example 1, a homogeneous and transparent solution was obtained. <The wood polymer is not a shell polymer, but corresponds to a soluble polymer used in conventional technology.> Polymerization was carried out in exactly the same manner as Synthesis Example 1 except that monomer (C) was added dropwise. The internal temperature rose to 105°C. After distilling off the remaining monomers, the white emulsion had no precipitates and almost no monomer odor. The particle size was 0.2μ and there was no particle size distribution. (
Comparison emulsion 4).

The emulsion obtained here has no internal crosslinked structure and no component corresponding to the shell polymer (S).

Example 1 (Production Example of Positively Charging Liquid Developer) Into 250 g of the emulsion obtained in Synthesis Example 1, 5 g of oil black 1-(BB (manufactured by Orient Chemical Co., Ltd.) dissolved in 40 g of xylene was added). The emulsion particles were colored by dropping while applying sound waves.

Next, a xylene solution 129 of 1% aluminum salt of steverite resin was added as a charge control agent to obtain condensates (concentrations) 1 to 1.

This conctner has a total of 10j2 with Isopar G.
A positively chargeable liquid developer (P-1 toner) was obtained.

Example 2 (Example of manufacturing a negatively chargeable liquid developer) The procedure up to the coloring of the emulsion particles was carried out in exactly the same manner as in Example 1, and 0.45 tJ of sodium salt of dioctyl sulfosuccinate was added as a negatively chargeable charge control agent. , got a conctner.

(I set the total of the q conctner with Isopar G
Diluted ON, negatively charged liquid developer (N-1 toner)
I got it.

Examples 2 to 13 The emulsions obtained in Synthesis Examples 2 to 13 were produced in the same manner as in Example 1 to make positively chargeable developers.
Although the particle chargeability was slightly different, good positively chargeable liquid developers were obtained (Toners P-2 to P-13).

Example 4 The emulsions obtained in Synthesis Examples 2 to 13 were produced in the same manner as in Example 2 to make a negatively chargeable developer.
Although the particle chargeability was slightly different, good negatively chargeable liquid developers were obtained (N-2 to N-131-ners).

Comparative Example 1 (Production of Comparative Liquid Developer) Using the emulsions synthesized in Comparative Synthesis Examples 1 to 4, a liquid developer for positively charging property was obtained in exactly the same manner as in Example 1 (Comparative P-1). ~4 toner, comparison N-1 to 4 toner)
.

Example 5 The P-1 toner obtained in Example 1 and the P-2 to 13 toners obtained in Example 3 were used as liquid developers, and EP-12 (
When the electrophotographic direct printing plate LOM-111S was made using Mitsubishi Paper Industries (Tai-made direct plate making IF!) at a slightly higher fixing temperature, images with firm edges were obtained in all cases, and the printed matter using this printing plate was It also had a beautiful finish.For comparison, Comparative P-4, which was 17 in Comparative Example 1.
In the case of toner, a smudge-like ghost appeared around the image area. The image also seemed to be distorted. Prints using this printing plate were not acceptable because the pattern of the image failure appeared on the prints.

Example 6 An ε-type copper phthalocyanine pigment dispersed in an acrylic resin with a high acid value was coated on an aluminum plate that had been subjected to a hydrophilic treatment and dried to prepare a printing original plate (binder/pigment ratio =
75/25>. After the original plate was positively charged by corona charging in a dark place, image exposure was performed.

After developing with the N-1 to 13 toners obtained in Examples 2 and 4 and Comparative Example 1 and the Comparative N-1 to 4 toners, heat fixing was performed.

The following three types of eluents were used as eluents for the non-image area, and the plate was immersed for 10 seconds and then washed with water to obtain an offset printing plate.

(Left below) Eluent A 20% potassium silicate (Gyudon Kagaku M) 70gK O
+-17g tota I 1 with water! Eluent B EDTA-41-f 2g butyl diglycol 20g monoethanolamine 40y tota I with water
1 I! Eluent C EDTA-4 1
29 benzyl alcohol
159N-methylethanolamine
309 water total
As for the 111 evaluation, the condition of the image after heat fixing and the condition of the image after processing with eluents A to C is 11! I guessed it.

(Hereinafter, blank space) Comparison N-41 to N-41 (without shell polymer) caused image defects after development. Further, with Comparison No. 1 to 3 toners, a good printing plate can be obtained with eluent A, but when elution treatment of non-image areas is performed with eluent B or C, which has high permeability, the toner image is also eluted. This means that the resist property against eluent is weak. -6 N that was 1q in the present invention-
Toners 1 to 13 are formed from particles with an internal crosslinked structure, so even with a highly permeable eluent, only the toner image area remains as a beautiful image, while the non-image area is completely eluted, resulting in a printing plate. Ta.

The printing plate obtained from Eluent A with 1q produced good prints even after printing 100,000 sheets, except for the comparative N-4 toner, but the printing plate obtained from Eluent C with N1 to 131-toners. Only those with images formed could withstand printing of 100,000 sheets.

Therefore, it can be seen that the three-layer emulsion having an internal crosslinking structure of the present invention is effective as an electrophotographic wet developer.

Procedure Ne City Masa n] (Voluntary) 1. Indication of the case 1986 Patent application No. 11087 2, Name of the invention Electrostatic photographic liquid developer 3, Person making the amendment Relationship to the case Patent applicant address 3-4-2 Marunouchi, Chiyoda-ku, Tokyo Contact Address: Mitsubishi Paper Mills Co., Ltd. Patent Department, 4-1 Toganemachi-chome, Katsushika-ku, Tokyo 125 Japan, FFI (600) 2111 4. Paper subject to amendment

Claims (1)

[Scope of Claims] An electrostatographic liquid developer comprising at least resin particles dispersed in a highly insulating hydrocarbon medium, wherein the resin contains the following monomer in the presence of the following polymer (S). A liquid developer for electrostatic photography, characterized in that it is a resin dispersion obtained by polymerizing (A), monomer (B), and monomer (C). Polymer (S): A polymer that is insoluble in the medium and has a carboxyl group, a hydroxyl group, or an amide group. Monomer (A): A monomer that is soluble in the medium and becomes insolubilized by polymerization. Monomer (B): A monomer that is soluble in the medium and forms a soluble polymer upon polymerization. Monomer (C): A monomer having two or more polymerizable unsaturated double bonds.