JPS60252367A - Production of liquid developer for electrophotography - Google Patents

Abstract

PURPOSE:To obtain a titled developer which has excellent dispersion stability and provides a toner image having excellent resistance to solvent and printing by dispersing and incorporating resin particles having a surface protective layer and having internally a crosslinked structure into a hydrocarbon medium having a high insulating characteristic. CONSTITUTION:The 1st polymer (e.g.; lauryl methacrylate/methacrylic acid copolymer) which is soluble in the hydrocarbon medium having a high insulating characteristic (e.g.; normal paraffin hydrocarbon) and having a polar functional group possessing adsorptive power with the 2nd polymer is dissolved in the hydrocarbon medium. A monomer (e.g.; vinyl acetate) having a polar functional group possessing adsorptive power with the 1st polymer and addition-polymerizable multifunctional monomer (e.g.; divinyl benzene) are added to the medium and are polyermized to form the 2nd polymer particles having the low solubility with the medium and having the internal crosslinked structure. A colorant, charge adjusting agent, etc. are then added thereto, by which the intended liquid developer for electrophotography is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel manufacturing method for a liquid developer for developing electrostatic latent images, and in particular has excellent dispersion stability and excellent solvent resistance for toner images obtained after development. It provides a liquid developer that imparts.

For example, one method for obtaining a printing plate is to electrophotographically charge and expose a printing original plate on which a photoconductive layer is provided on a support, and then develop it with a liquid developer to form a toner image. After forming and fixing, the non-image yJ! 2. In the method of obtaining a printing plate by eluating (etching) a part of the toner image, the eluate is used to impart sufficient solvent resistance or resistivity (hereinafter referred to as etching resistivity) to the toner image. ◇ In order to impart such etching resist properties to a toner film, conventionally, for example, Japanese Patent Applications No. 57-4157 and No. 57-1 have been proposed.
0325, 57-21829, methods have been taken to prevent the eluate from penetrating the toner film by including styrene or the like as a copolymer component as a toner resin component. When the above-mentioned printing original plate is developed by charging and exposing it to a developer, there are disadvantages such as the capri part being difficult to completely elute during the elution process, and the edge partial pressure of the image area lacking sharpness. On the other hand, the liquid developer obtained in the present invention contains resin particles dispersed in a highly insulating medium as a basic component, and forms a crosslinked structure inside the resin particles, so that the resin particles adhere to the liquid developer. The image area resin film formed by this process becomes a crosslinked film, which prevents the eluate from penetrating during the elution process and provides good elatin and graze properties, and the resin particles themselves are crosslinked during fixing. Because of this, the particles do not melt and maintain their granularity even after the film is formed. Therefore, a film in which the particles are densely filled with light shows good etching resistance, but on the other hand, if there are gaps between the particles, the particles will not melt and form a film even after fixing. , it shows the same elution rate as the non-image area without hindering the penetration of the eluate. Therefore, the etching resist properties are influenced by the presence or absence of particle gaps, and as a result, the etching properties are extremely sharp. Therefore, the capri portion in the non-image area is eluted smoothly and the sharpness of the edge portion in the image area is increased.

Furthermore, another feature is that the image area formed by the crosslinked film according to the present invention has extremely good printing durability due to its excellent solvent resistance and the like.

The electrophotographic wet developer according to the present invention basically consists of resin particles dispersed in a highly insulating hydrocarbon medium, a dye or pigment as a coloring agent, and a charge control agent to impart a positive or negative charge to the particles. configured. One of the features of the present invention is that the resin particles have a crosslinked structure inside the particles, and a method for obtaining the resin particles having a crosslinked structure will be described below.

The resin particles having a crosslinked structure are basically composed of a solvent-soluble polymer (hereinafter referred to as a first polymer) and a solvent-insoluble polymer (hereinafter referred to as a second polymer). Solvent-soluble polymers and solvent-insoluble polymers both have relatively polar functional groups, and the interaction pressure between these functional groups causes the first polymer to be adsorbed onto the surface of the second polymer particles. , forming an adsorption protective layer that prevents agglomeration and fusion between particles. The α-functional groups that interact with each other include any one functional group selected from group (I) below, and group (
II) means a combination with any functional group selected from group II).

Group (I); (acidic group) Group (II); (basic group) -NH! , -N(OnHzn+l)g(n=l~3),
Specific examples of monomers containing functional groups belonging to Group CI) include acrylic acid, methacrylic acid, 3-vinylpropionic acid, maleic acid 01-0 alder ester, fumaric acid 01- 08 Monoalkyl ester, maleic acid, itaconic acid, crotonic acid, sulfoethyl acrylate, sulfoethyl methacrylate, sulfopropyl acrylate, sulfopropyl methacrylate, 2-methyl-3-sulfopropylacrylamide, P-hydroxystyrene, P-hydroxybenzyl acrylate , P-hydroxybenzyl methacrylate, and the like.

Examples of the 10 monomers containing functional groups belonging to group (6) include vinylamine, N,N-dimethylamine ethyl acrylate, N,N-dimethylaminoethyl methacrylate, N,N-diethylaminoethyl acrylate, and N,N-dimethylamine ethyl acrylate.
-diethylaminoethyl methacrylate, N,N-dipropylaminoethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxyglobyl acrylate, 3-hydroxypropyl acrylate, 2-hydroxy-3-chloropropyl acrylate, 1,4-butylene glycol Monoacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl methacrylate, 2-hydroxy-3-chloropropyl methacrylate, 1,4-
PETIRE/Glycol monomethacrylate, carpitol acrylate, methoxyethyl acrylate, ethoxyethyl acrylate, butoxyethyl acrylate, methoxypolyethylene glycol ac IJ L/-) (
oH.

NiOH−Ou u 4 o, n4o) nOH,, n =
l~25) Tetrahydrofurfuryl acrylate, glycine n=1~25), polypropylene glycol monomethacrylate (OH,=OOGH,)-0004OH1
lyl methacrylate, methacroxypropyltrimethoxysilane, glycidyl methacrylate, vinyl acetate,
N-vinyl-2-pyrrolidone, acrylamide, methacrylamide, N-tsrt-butylacrylamide,
N-1@rt-octylacrylamide, N-butoxymethylacrylamide, diaseptone acrylamide,
N-vinylimidazole, N-vinyl-2-methylimidazole, 4-vinylimidazole, l-vinylpyrrole, 3.5-dimethylvinylpyrazole, 4-vinylpyridine, 2-methyl-5-vinylpyridine, 9-vinylacridine , 4-vinylquinoline, 2-vinylquinoline, 01-4 alkyl vinyl ether, and the like.

The first polymer used in the present invention is, for example, a polymer that is soluble in the highly insulating hydrocarbon medium used,
In order to impart Loe bath properties to the polymer, K is selected from the above groups (
It is desirable to introduce a monomer selected from the following general formula (a) as a copolymerization component in addition to the monomer that cleaves the a functional group belonging to I) or group (6).

(8). □=7 in total X=H, OH8, Y ;OOx Or, lHx-+l(
6≦G2 )==OnH,,+1 (Z≦n≦20) =00. H,, +1 (6≦P≦20) The ratio of the monomer represented by general formula (a) to the monomer selected from group (I) or (6) is generally 0.7 in molar ratio. As mentioned above, it is preferable to achieve a value of 0.3 or less.

The highly insulating hydrocarbon medium referred to here includes, for example, normal paraffin hydrocarbons, isoparaffin hydrocarbons,
Examples include alicyclic hydrocarbons, aromatic hydrocarbons, halogenated aliphatic hydrocarbons, etc., but isoparaffinic hydrocarbons are preferred, such as Shell Silua 1 (manufactured by Shell Oil), Isopar 〇, Isopar H, Isopar K, and Isopar. L (manufactured by Futsuso Miyu), Ipeen Rubent (Idemitsu Seki Taiyu), etc. can be used.On the other hand, as a monomer that provides the second polymer constituting the dispersed particles, which is practically unethical to the above-mentioned carrier liquid. Basically, in the monomer state, it is soluble in the above-mentioned carrier solution, but when it forms a polymer, the solubility in the carrier solution decreases, and any monomer can be used as long as it has the property that the polymer precipitates.

In this case, if the monomer itself has a functional group belonging to Group (I) or Group (2), is it possible to polymerize as a single monomer to obtain dispersed particles, or in other cases? , using a monomer that does not have a functional group belonging to group (I) or (6),
In the case of forming a polymer, dispersed particles can be formed by introducing a suitable heptamer selected from group (I) or (6) as a copolymer component. Alternatively, in this case, particulate crosslinked dispersed particles can be obtained by introducing a multi-α-functional monomer as a copolymer component into the monomers forming the second polymer. At this time, it is preferable that the ratio of the multi-g bait monomer is approximately 20 mol % or less; if the multi-a-potent monomer is combined in a ratio higher than this, crosslinking between particles often progresses, resulting in dispersion. The entire system may solidify without forming particles.Specific examples of the polyfunctional monomer in the present invention include VCFi,
For example, divinylbenzene, neopanthyl glycol diacrylate, ethylene glycol diacrylate, polyethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butylene glycol diacrylate), 1,6-hexane glycol diacrylate , diglopylene glycol diacrylate, polypropylene glycol diacrylate, vinyl acrylate, 2,2-bis(4-acryloxyjethoxyphenyl)propane, 2,2-bis(4-acryloxydipropyloxyphenyl)propane, trimethylol Propane triacrylate, tetramethylolmethane triacrylate, triacryl formal, triacryloyloxyethyl phosphate, tetramethylolmethane tetraacrylate, tris (2-hydroxyethyl) in cyanur triacrylate, dibromneopentyl glycol dimethacrylate, acri methacrylate, Oleyl methacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, l,3-butylene glycol dimethacrylate, 1.
4-Butylene glycol diacrylate San glycol diacrylate, neopentyl glycol dimethacrylate, polypropylene glycol dimethacrylate, 2.2-bis(4-methacroxyethoxyphenyl)propane, 2.2-bis(4-methacroxyethoxyphenyl) ) propane, trimethylolpropane trimethacrylate, trimetacroyloxyethyl phosphate, tris(2-hydroxyethyl)incyanuric acid trimethacrylate, and the like.

Further, as the hexamers forming the second polymer, in addition to those belonging to group (1) or (6), and the above-mentioned polyfunctional monomers, examples include styrene and its derivatives, acyl sulfuric acid, 01/-(1, alkyl ester of methacrylic acid, methyl vinyl ketone, ethyl vinyl ketone,
Examples include vinyl propionate and vinyl pivalate.

The dispersed resin particles obtained in the present invention are characterized by having resin particles having an internal crosslinked structure and an adsorption protective layer adsorbed onto the surface of the particles. On the other hand, for example, dispersed particles can be formed by copolymers of multicomponent monomers and monocomponent monomers, but compared to the two-component polymer systems described above, these -component polymer systems produce particles It is difficult to control the particle size, and it is difficult to obtain particles with a particle size of, for example, lam or less and excellent dispersion stability that can withstand long-term storage.

The particle size of the internally crosslinked fractional resin particles obtained in the present invention is 0.
．． 05 μm to 5. Can be controlled arbitrarily within a range of about am,
In addition, a particle size distribution close to monodisperse can be obtained, but for practical purposes, particles with a diameter of 0.4 am or less are preferable.

In order to use the polymer dispersion obtained according to the above description as an electrophotographic liquid developer, the dispersed particles may be colored and charged. As the colorant for the dispersed particles, any general colorant (known as a colorant for wet developers can be used); examples include oil-soluble azo dyes such as oil black and oil red, and basic azo dyes such as Bismarck brown and chrysoidine. Dyes, acidic azo dyes such as Wool Black, Amido Black Green, Blue Black HP, Direct Day Black E.

Direct dyes such as Congo Red, Sutan Violet,
Examples include anthraquinone dyes such as acid blue, carbonium dyes such as auramine, malachite green, and crystal violet Victoria blue, rhodamine dyes such as rhodamine B, and kino/imine dyes such as safutunin, nigrosine, and methylene blue.

Examples of pigments include carbon black, phthalocyanine blue, phthalocyanine green, washing red, and benzidine yellow. Also, pigments with added surface treatment, such as carbon black dyed with nigrosine,
Craft carbon, silicon oxide fine powder dyed with Rhodamine B, microlith plue, etc. can also be used.

As for the method of coloring the dispersed polymer particles, there is a method in which the dye is previously dissolved in a solvent that dissolves the dye used, and this dye solution is added dropwise to the dispersed polymer liquid and stirred. In this case, it is soluble in dyes. Furthermore, it is desirable to use a bath agent with relatively insulating properties and a high boiling point as a solvent for the dye. A wet developer for electrophotography that can withstand light use can be produced without removing the solvent for the dye. Therefore, if you use a dye that has a relatively high solubility in organic solvents, such as an oil-soluble dye, and reduce the contribution of the solvent to the dye,
There is no need to remove the solvent after coloring the dispersed polymer particles.

Furthermore, in the polymer dispersion system, the adsorption functional group contained in the dispersed particles can be used as an adsorption point for the dye or
By introducing a highly functional group into the polymer, the dye or pigment adhesion (adsorption capacity) increases, making it difficult for the dye or pigment to be desorbed from the dispersed particles after coloring. 2 by introducing a functional group having
If a dye is used for coloring, when the dye solution is added to the dispersed polymer liquid as described above, the amount of solvent for the dye is small and the dye precipitates in the dispersed polymer liquid. However, the precipitated dye is molecularly adsorbed onto the polymer particles, making it possible to successfully color the polymer dispersed particles. Therefore, the solubility of the dye during coloring is no longer important, and the amount of solvent for the dye can be extremely reduced. If pigments and the like are selected, it is possible to freely produce a toner with a positive charge or a toner with a negative charge.

The charge control agent used in the wet developer of the present invention includes:
Examples include copper oleate, cobalt naphthenate, zinc nanthenate, manganese naphthenate, cobalt octylate, lecithin, sodium dioctyl sulfosuccinate, and aluminum salt of steperitrozin.

Synthesis Example 1゜L! equipped with a stirrer, thermometer and nitrogen inlet tube! In a flask, 500 g of Ivy Solvent (manufactured by Idemitsu Petrochemical Co., Ltd.) consisting of isoparaffinic hydrocarbons and lauryl methacrylate 100 # were placed.

Add methacrylic + *511 and use AI as a polymerization initiator.
Add 1 g of BN (azobisisobutyronitrile) to 80℃
Polymerization was carried out on a water bath for 5 hours to obtain a viscous polymer solution.

Then, take the product solution and transfer it into a one-noon flask equipped with a stirrer, a meter and a metal inlet tube, add 300 g of Ivy Solvent, and place it on a 70 °C water bath to form crosslinked particles. Polymerization was started by adding 10# of ethylene glycol diacrylate, 80jl of methyl methacrylate, and N,N-dimethylaminoethyl methacrylate (N,N-dimethylaminoethyl methacrylate)loI as monomers, followed by the addition of AIB No. and 6j'. After the N-combination was completed, it was cooled to room temperature and a part was observed using a scanning electron microscope.
Stable, nearly monodisperse particles with a particle diameter of 0.2 μm were obtained. Also, the product was coated on a polyester film for 12
After treatment at 0°C for 3 hours, the coated surface was observed with a scanning electron microscope, and a film that retained the particle morphology was found @r!
II was done.

For comparison, the same amount of 2-ethoxyethyl acrylate was added instead of ethylene glycol diacrylate as the multi-α-functional monomer used in Example 2 above, and the other components were kept the same, and KML synthesis was performed in the same manner. To find out whether we were able to obtain particles, we applied the product of this removal onto a polyester film and heat-treated it in the same manner as in the above example, and then observed the scratched fabric using a scanning electron microscope, but the particle shape no longer changed after heating. It was not retained and had a uniform surface.

Synthesis Example 2: Take 100.9 of the lauryl methacrylate-methacrylic copolymer solution obtained in Synthesis Example 1, add ivy solvent aooIi, and add vinyl acrylate 1
Add 2 F, 78 g of vinyl acetate and N-vinyl-2-pyrrolidone iog, and mix on a 70 °C water bath.
Polymerization was initiated by adding 6I.

The product was a milky white emulsion δ having a particle size of 0.20 μm and excellent dispersion stability.

Synthesis Example 3: 1 equipped with a stirrer, 2 thermometers, and a nitrogen inlet tube! Ivy crane pen in the flask) 500 #.

lauryl methacrylate) 80#SN, N-dimethylaminoethyl methacrylate 20.9, AIBN
ljl was added and polymerization was carried out on a water bath at 80°C for 5 hours to obtain a polymer solution.

Then take the product solution U15ON and mix it with a stirrer,
Transfer to a 1-well flask equipped with a thermometer and nitrogen inlet tube, add Ivy Solvent 300I, and place on a 70°C water bath to form crosslinked particles with vinyl acrylate 101, vinyl acetate 80#, crotonic acid io,
t′:J? and 0.9 of AIBNl as an initiator to initiate polymerization. The product was mixed with emulsion a having a particle size of 0.15 μm and excellent dispersion stability.

Synthesis Example 4゜Laurylmethacrylate-N,N obtained in Synthesis Example 3
-Dimethylaminoethyl methacrylate copolymer solution/
[Take 150#, add ivy solvent, 1.3
- Add 8 g of butylene glycol diacrylate, 70 pSN of methyl acrylate, and 12 I of N-diethylaminoethyl acrylate, and add A I B N on a water bath at 70 °C.
One batch was started by adding OBg.

The product was a stable white emulsion with a particle size of 0.25 μm.

Example 1. Preparation of original printing plate As a binder, lOg of octylharfester form of styrene maleic anhydride (acid value 165) was mixed with xylene 8
0g and butanol 2011'J? 2,5-bis(4-diethylaminophenyl)-1 as an organic photoconductive compound was dissolved in a mixed solvent of 20 g of and tetrahydrofuran.
, 3,4-oxadiazole (8 g) was dissolved, 5 d of a 1% methanol solution of ethyl violet was added as a sensitizing dye, and the remaining volume was adjusted to 150 g with xylene. The resulting photosensitive solution was coated on an anodized aluminum plate with a film thickness of 4 μm.
After coating and drying, a printing master plate was created.

Next, using the emulsion obtained in Synthesis Example 2, a liquid developer was manufactured by the following method.

Orient Chemical Co., Ltd. Oil Black HB B 1,2I
was dissolved in 15 g of xylene, 0.3 g of aluminum stearin was added thereto, and the mixture was added dropwise to the emulsion liquid 50I with stirring. The obtained colored emulsion liquid was added to Isopar G (Esso Petrochemical Company M) 3.7! It was diluted to make a liquid developer.

The printing original plate was charged, developed with the above liquid developer, and after fixing was etched with an aqueous etching solution containing benzyl alcohol and triethanolamine. A printing plate was obtained.

Example 2゜Example 1 using the white emulsion cod obtained in Synthesis Example 2
Same as samurai liquid developer. When the printing original plate shown in Example 1 was charged, exposed, developed, and etched with an aqueous etching solution containing benzyl alcohol and triethanolamine, i! j f8! The portion showed excellent resistivity, and a printing plate f was obtained.

Claims (1)

[Claims] In a method for producing an electrophotographic liquid developer comprising resin particles dispersed in a highly insulating hydrocarbon medium, a first liquid developer having a polar functional group that is soluble in the medium and capable of adsorbing an M2 polymer; A monomer mixture containing at least a monomer having a polar functional group capable of adsorbing the first polymer and an addition-polymerizable polyfunctional monomer is prepared under conditions in which the polymer is dissolved in the medium 9. A method for producing a liquid developer for electrophotography based on fractional resin particles, which is patented in that a second polymer of particles having an internal crosslinking structure and having low solubility in the medium is produced by polymerization.