JPS59212850A - Electrophotographic liquid developer - Google Patents

Abstract

PURPOSE:To enhance electrostatic charge stability, dyeability, and fixability by using an N-vinyl-heterocyclic ketone compd. as the component of a copolymer to be used for a liquid developer. CONSTITUTION:Copolymer particles A are made from (a) an additionally polymerizable compd. having basic nitrogen, (b) N-vinyl-heterocyclic ketone, (c) an additionally copolymerizable compd. excluding (a) and (b), and they are allowed to adsorb an additionally copolymerizable compd. B for a dispersing resin. A liquid developer is prepd. by mixing said copolymer A, said compd. B and a highly insulating hydrocarbon as a dispersing medium, further with a colorant dye and a charge controller. As (a) dimethylaminoethyl metachrylate, dialkylaminoethyl (meth)acrylate, etc. are usable, as (b) N-vinyl-pyrrolidone, N-vinyl- piperidone, etc. are usable, and as (c) styrene, alkyl acrylate, etc. are usable.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to a liquid developer for electrophotography and a method for producing the same. It exhibits coloring properties and fixing properties, and has various advantages such as little change in development characteristics even during long-term storage or use. As a liquid developer for electrophotography, it has been well known to use a pigment, which is adsorbed onto the pigment to stabilize the dispersion, and then diluted with the pigment in a highly insulating hydrocarbon medium using a dispersion resin. However, with this developer, the process of mechanically pulverizing the pigment takes a long time, and the primary particles of the pigment obtained in this way also tend to aggregate with each other, making it difficult to use the dispersing resin. Even when used, there is a serious drawback in that particles tend to aggregate or settle over time. Therefore, although a developer using a pigment such as carbon black has the advantage that a high image density can be easily obtained, it cannot be said to be preferable.

On the other hand, instead of dispersing the pigment, [)IJ
Fluid/column liquid developers in which a resin is dispersed in a recording medium are also known. In this type of developer, the resin surface generally has low polarity, which makes it difficult for charge control agents such as metal soap used to charge the particles to be adsorbed, and the resin particles of such charge control agents tend to deteriorate over time. Due to desorption from the surface, the amount of charge on the particles decreases, resulting in a change in development characteristics. Furthermore, adsorption of the colored dye to the particles is similarly weak, and only low-density images can be obtained. The ability of a liquid developer for electrophotography to absorb aqueous solution is obvious, and a liquid developer that has good dispersion stability, charge stability, and fixing properties, and is capable of developing a high density is desired. However, the reality is that there have been almost no liquid developers that simultaneously satisfy these various properties at a high level. 1] The purpose of the present invention is to provide the following.

As a result of intensive research, the present inventor-25- found that (A) at least the following (, I), (1)
) and ((1)) and ([1) copolymer particles soluble in the medium containing a compound having a carboxyl group. It has been found that the objects of the present invention can be achieved by an electrophotographic developer characterized by containing a copolymer, (C) a colored dye, and (1) a charge control agent. Ta.

The liquid developer of J that emits 1 (0) copolymer particles (
The 71′-converted copolymer of
Since it is adsorbed as a fat, the stability is determined to be 11 by the conventional graph l-7ij platform method, which is similar to J fat. Such a molecule +
<To produce particles, in the medium, the 2Q; l: body-soluble copolymerization +<-(It), 1) It (a), (
+3) and (C) are present and polymerized, the mono r-compounds ii, , l;, J, coj, body (C.1. As a coalesced particle, the above-mentioned (13) 159 coalesces are formed on the particle surface in a state of 'Ji, y+,'r'.

Above r'! :According to the waiting method, the (C) component of the sunalene or acrylic monomer I and the dimethelaminoethermethacrylate-1.AI are added to the medium. A developer with relatively good dispersion stability could be obtained even by using a copolymer with the (,) component. But with? Although the eε type developer has a stability of about 11/11, it has poor affinity with charge control II:1, has poor charge stability, and has a high affinity with color dyeing. Poor sex,
The image density is low, which is equal to the drawbacks of '1) Gen/Z.
) and (0 components include N such as N-hynyruvirolidone)
One of the 41i characteristics lies in the discovery that the problem can be solved by co-combining a -hinyl-heterocyclic ketone compound as a component (1), and this is because l) The carfoquinol group of the copolymer (13) is electrically intermediated with the basic nitrogen atom (a) and the endocyclic carbonyl group (ketone) of the copolymer particle (A),
11. The affinity of the intracyclic nitrogen atom (1) bonded to the hinyl group with respect to the calhoquinol group greatly improves the dispersion stability, and also increases the electron +'r:i Increased octadity of anti-smoking agents and coloring dyes,
Further improvement in charge stability and adsorption/i' dyeing t・1
It is considered that the image density is improved due to the increase in the amount.

t; ji, l, (I': 1 addition Jl'i
; The use of a synthetic compound or an N-hinyl-heteroketone compound as a dispersion resin is disclosed in, for example, Japanese Patent Publication No. 52-
2627 or Lu Gongsho 51. -1'jbO, same 5th year
1-.10465 and the like. However, all of these are used as resin components soluble in the medium for dispersing Xf color Mj materials such as carbon black, and are intended only to improve the dispersibility and stability of Face 4.1. As a component of the insoluble resin particles and as a charge control agent, the absorption A of the colored dye 1 is This is different from its use as a sex ingredient.

``i, a monovalent nitrogen-containing compound (,1)
as methylaminoetheracrylate, /
dialkylaminoethers (meth) such as noteraminoethyl acrylate V-1, diethyl-laminoegul methacrylate, and 7''-1-laminoethyl acrylate;
Acryle-1-1N-vinylimidamer, ~-vinyl-2-methylimignol, +-hinyl: yy-
1-vinylpyrol, 3,5-dimethylhinylvirazole, hinyl/danol, hinyl detrazole, 2-
7-vinyl 7-sooxyazole, 5-vinyl 1-methylthiazole, N-α-acrylogyethylimitasol, 1-β-acryloki 7-ethylindole, 2-vinylquinoline, 4-vinylquinol/, 0-hinyl acridine , 2-vinylpyridine, 1-vinylpyridine, and 2-methyl-5-vinylpyridine.

The basic nitrogen in these compounds acts as a component of the insoluble compound (Δ) between the carboxyl group of the HiJ soluble compound (11) adsorbed to the particle. phase r7. Suction R, 'f'l'lj acts as a functional group (atom), and N---Hinyl? It is thought that extremely high dispersion stability is achieved due to the addition of the strong (11 interaction), which is thought to be based on the hydrogen bond between the n-ring monoton compound and the carboxyl group.

The N-vinyl-heterocyclic ketone compound has one ring nitrogen atom bonded to a hinyl group and a carbonyl group (triton) next to the nitrogen atom. These are vinyl monomers such as uLt, N-vinyl-pyrrolidone, N-vinyl-oxanelidone, and N-hinylubiperidonna.

Component (C) of the insoluble copolymer particles (A) includes, for example, styrene and its derivatives, acrylic (52-4, or C1-C5 alkyl ester of methacrylic acid, maleic late mono-2-ethylhexyl), I/inic acid mono 1
1-octyl, 7-ethylhexyl nmarate,
Fumaric acid mono 1]-octyl, acrylonitrile,
Methacrylic acid 1. Examples include IJ-1, hydroxy/ethyl methacrylate-1, ethoxyethyl methacrylate-1, metquinethyl methacrylate, and the like.

The blending ratio of monomers (a), (1)) and (c) above can be any ratio, but the weight ratio is (, I), (
l]):(0'=1~:30:]~30:40~98 can be used as a guide.(, ]), (1)) and or<
The compounds exemplified in c) are not limited to these, and include at least one compound from each of Ushidani J), (I)) and oJ(c).
If seed compounds are used, it is not limited to terpolymer particles, but can be made into multi-component copolymer particles further north.
The medium-soluble copolymer (13) used in the present invention is:
-) An addition-polymerizable monomer having a norphogycyl group, such as acrylic acid, tuacrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, etc., is included as a copolymer component. Such a medium-active copolymer can be prepared by co-merging a monomer having a carboxyl group with an addition-polymerizable 1:mer, generally as described below. can get..

Formula (1) CI+2-(nees \211 or (ci II: 3, \'=CQOC1 711
1+l (m=6-22), 20).

Typical examples include lauryl methacrylate, 2-su/L-hegyflunotacrylate l-12-ether/
Notfu'acrylate, Stepf'Rino L methacrylate,
Vinyl stearyl ether, ">U')/L'acrylate, setermec acrylate, etc. are substituted with (
-Tegura JLru. The copolymer (No. 1) has O1' in the medium.
The monomer that is soluble and has a carboxylic group is not particularly limited, and for example, hydroquine alkyl (meth)acrylate or the like may be included as a copolymer component. It is generally preferable that the proportion of this in the copolymer (13) is about 1 to 30% by weight.

As mentioned above, the liquid developer for electrophotography of the present invention is obtained by polymerizing the soluble copolymer (13) in a highly insulating hydrocarbon medium, and in the presence of the polymer ( Although it is particularly unfavorable to produce the defective co-topolymer of (A) by copolymerizing the seven polymers of (414),
A copolymer of 1 and a copolymer of (1$) were each synthesized separately, and both of them were mixed with a common dissolving compound (r7) (in layman's terms), and the solution was mixed with Mi in a recording medium. Even if I put it down, I can still do it.

/Al used for misexplosion 1jJJ: It is an organic acid medium with high electrical insulation properties, such as 117j:
Normal paraffinic hydrocarbons, in-paraffinic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, halokenized 1
1'tf rib 1j), hydrocarbons can be used, but isoparaffinic hydrocarbons are preferable, such as shell silua 1
(/L Oil), Aitzba-G and I:/Bar If
and ``Isobar L'' (manufactured by Enono Oil) and Ivy Solvent (manufactured by Idemitsu E1 Oil) <11 can be used.

In order to use the polymer dispersion prepared in accordance with the description in Section 2 as a liquid developer for electrophotography, the dispersed particles must be
All you have to do is color it and give it a charge. As for the coloring dye of the dispersed particles, any coloring agent generally known as a coloring agent for wet type developers can be used.

For example, oil-free azo dyes such as oil black and oil red (Hismark Brown, Chryso 17), basic non-dyed books such as wool blank, timid blank green, blue black IIF, etc. Acid Aso Dye 91,
direct dyes such as Konoko Red, Sutan Violenoto, A7 Throat Blue Tachibana anthraquinone dye A1, carbonium dyes such as Auramine, Malachite Green, Crystal Violet Victoria Blue, and rhodamine J3 (l)- Dyes such as quinoneimine dyes such as damin dye, zafranin, -nigrosine, and noteren blue are exemplified.

Regarding the method for coloring dispersed polymer particles, there is a method in which the dye is dissolved in advance in a solvent that dissolves the dye used, and this dye solution is stirred under the dispersed polymer (1ζ). At this time, it is preferable that the solvent for Dye A'-1 be mixed with the isoparaffinic hydrocarbon solvent used as the medium. Furthermore, it is desirable to use a solvent with relatively insulating properties and a high υ1) point as a solvent for the dye. 1. When used,
For example, as seen in JP-A-57-18738, it is possible to produce a liquid developer that is sufficiently usable as an electrophotographic liquid developer without removing the solvent for the dye.

Therefore, using dyes that have relatively high solubility in organic solvents, such as oil bath・II: and dye I'・1.
Keeping the amount of solvent to dye small eliminates the need to remove the mi'jll after coloring the dispersed polymer particles.

The charge control agent used in the liquid developer of the present invention includes:
Examples include copper oleate, cobalt naphthenate, sodium naphthenate 1), naphthi/mantuno acid/cobalt octylate, lentene, sodium dioctyl sulfosuccinate, aluminum salt of steverytrozin, and the like.

Liquid developer of the present invention-1, charge control agent, dyeing agent 1, -5
．． The difference in selection is toner with positive charge or toner with negative charge.
It is possible to freely produce I.

Examples of the present invention are shown below.

Example 1 One stirrer, thermometer and nitrogen inlet tube (+iii 1)
In a tc1t flask, Ivy Solvent (manufactured by Idemitsu Menu Oil Co., Ltd.) 5f consisting of isoparaffinic hydrocarbons, lUP, 100 g of lauryl ivy acrylate, 57 g of acrylic acid
was added, 11 (benzoyl peroxide) was added as a polymerization initiator, and a polymer without IH1 polymerization was obtained at 5 hours on a bath at 85°C.

After that, take the product solution 1011 and add it to the stirrer, thermometer, dropping funnel, and nitrogen gas tube (jii e fi 11
Transfer to a flask, add 300f of Ivy Norchen, and add 10g of methyl methacrylate as a monomer to give an insoluble copolymer from a dropping funnel on a 70°C water bath.
A mixture of n-butyl methacrylate 757,/methylaminoethyl methacrylate-1-10&, N-hibinipyrrolidone: 37 and polymerization initiator A, 1 g of 113N (azohisinbutyronitrile): for a period of time. 1;
4 down/ko. Thereafter, under an atmosphere of 4 liters of nitrogen, 1.15 liters of nitrogen was added at 13:00, and after 4 hours of cooling, the mixture was cooled to room temperature. The product is a white colored composite resin dispersion with extremely stable dispersion. Emaru with Tsuketo
/yo/ A solution prepared by dissolving Yu'JL, Ollief 1-Chemical Co., Ltd. Oil Yerr''-(lciS5f/ in Ky7ren 2Of) was added dropwise to the liquid while stirring.Furthermore, 1g of stearin 1Ryo aluminum was added as a charge control agent. After that, it was diluted 50 times in Buoy Solvent to prepare a toner solution/ζ0 The obtained toner was a positively charged l·toner exhibiting good dispersion stability.

This toner was suitable as a liquid developer for electrophotographic offset masters using zinc oxide, exhibited sufficient fixability and high image density, and was free of lθ blur.

This effect was maintained even during long-term running development.

Reference Example Toner QJ1 was produced in exactly the same manner as in Example 1 except that N-vinylpyrrolidone was not used.It was inferior to the toner of Example 1 in both charging stability and image density.

Example 2 Ivy solvent 20Uf, styrene 40g, methyl methacrylate 30g, 1]-butyl acrylate-1 were added to 1500f of lauryl methacrylate-methacrylic acid copolymer synthesized as shown in Example 1 in 10% solution.
・25i7 dimethylaminoethyl methacrylate 10
7, N-vinylpyrrolidone 57 and AlI3N1.5
F was added, and the mixture was heated and stirred at 75° C. for 5 hours under a nitrogen atmosphere.

Thereafter, it was manufactured in the same manner as in Example 1. The same results as in Example 1 were obtained for Y4J. This toner was suitable for producing a lithographic printing plate by etching an organic photoconductor-containing photosensitive layer with an alkaline solution, and exhibited good resistivity.

Example 3 Example 2 was repeated except that N-vinylpyrrolidone in Example 2 was replaced with N-vinylpiperidone, and similar results were obtained.

Example 4 Repeat Example 1. However, /notylaminoether methacrylate was replaced with 'N-hinylpyridine. 7. Results similar to those in Example 1 were obtained.

Example 5 In place of laurylnotacrylate-1 in Example 1, K2-ethylhedylnotacrylate was used. The same results as in Example 1 were obtained.

Examples Example 2 (except that 4US was replaced with Hyctoria Blue-27 (methanol solution) and aluminum stearate was replaced with aluminum j of stehelyrosin;,, <+y)
According to Example 2.

Similar results are shown in 11).

Examples 7 to 11 Example 2 is &'is returned/this. However, basic nitrogen containing 3
Regarding the compounds, the following compounds were used. 11) Both results were similar.

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Claims (1)

[Claims] (1) A highly insulating hydrocarbon medium containing (→ copolymer particles that are substantially insoluble in the above-mentioned particles and comprising at least the following (-), (b), and (C); (B) carboxyl A liquid developer for electrophotography, characterized in that it contains a copolymer soluble in the medium containing an addition polymerizable compound having a group, (C) a colored dye, and (D) a charge control agent. .