JPS5816249A - Liquid developer for electrostatic latent image - Google Patents

Abstract

PURPOSE:To form a clear and stabilized image and to obtain a liquid developer having good shelf stability, by dispersing a resin contg. a coloring agent and a specific beta-methacryl-oxyethyl acid monomer as a composing unit in a carrier liquid. CONSTITUTION:A coloring agent and a copolymer resin contg. a monomer A expressed by a formulaI(R denotes H, CH3; n,m denote 1-3) and or a monomer B expressed by a formula II (X denotes a group expressed by formulas III, IV) as a composing unit are added and dispersed in a carrier liquid. As said copolymeric resin, such resin is used as those in which a monomer D having a glycidyl group is graft-copolymerized to a copolymer of preferably the monomer A and/or the monomer B with the monomer C expressed by the formula V[X, represents a group VI (1<=p<=20)]. beta-Methacryloxyethyl succinate etc. are used as a monomer A to be used for this purpose, and beta-methacryloxyethyl phthalate etc. are used as a monomer B.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid developer for developing electrostatic latent images.

Development of an electrostatic latent image formed on an electrophotographic photoreceptor (a photoreceptor layer is provided on a conductive support) or an electrostatic recording material (a dielectric layer is provided on a conductive support) The liquid agent used for this is generally a colorant and a resin, together with a polarity control agent if necessary, uniformly dispersed in a highly insulating carrier liquid such as paraffinic or isoparaffinic hydrocarbon. A copolymer containing an acid component such as acid, methacrylic acid, crotonic acid, maleic acid, etc. as a constituent unit is used. However, these acid components have a high solubility in water, and conversely a low solubility in the carrier, and low reactivity, making it difficult to obtain a copolymer with a uniform composition free of unreacted components. Although unreacted components can be removed by purification, such extra steps increase the cost of the product and must be avoided. For this reason, conventional liquid developers that use acid component-based copolymers as resins are particularly susceptible to the effects of moisture due to unreacted acid components, resulting in agglomeration, sedimentation, or polarity changes during storage or repeated use. The main drawback of the present invention is that performance deteriorates and clear and stable images cannot be formed. The object of the present invention is to provide a liquid developer for electrostatic latent images with excellent properties.That is, the developer of the present invention is a liquid developer for electrostatic latent images containing a colorant and a resin dispersed in a carrier liquid. The resin has the general formula I CH, = C-Coo (OH,)noco (CH
,)mCOOH (where R is H or CHs group, n and m are each an integer of 1 to 3, 0) and the general formula ■CH,=C-Coo (CH,)nocox (however, R , n are, as mentioned above, X is a copolymer resin containing as a constituent unit at least one monomer from the group consisting of monomers B represented by O. By using monomer A of general formula I or monomer B of general formula (2), which has low solubility in water and high reactivity, in place of the acid component that causes the above-mentioned drawbacks as a constituent monomer, the desired effect can be achieved. By the way, the comparison with conventional acid components is as follows.

Water bath decomposition (20°C) Reactive acrylic acid (conventional product) ω Small-sized acrylic acid (conventional product) 01) Monomer A of general formula I and or The seven squares B of the formula ■ and the general formula ■ CH, = C-Xl [R is as mentioned above, and X is -COOCPHtP+t(1
≦p≦20)] A copolymer with monomer C represented by 5- is graft-polymerized with monomer D having a glycidyl group.

2) Monomer A of general formula I and/or monomer B of general formula (1) and general two (2) CH,=C-X.

[R is as mentioned above, X2 is -COOCXHIX+1 (6
≦X≦20)] Monomer D having a glycidyl group is esterified into a copolymer with monomer E represented by As mentioned above, Y is -COOCyHty+.

(l≦y≦4), -0000, H,, +1 (1≦Atsushi≦6).

Monomer F represented by and/or general formula ■ 6-CH,=C-Z [R is as described above, 2 is -COOCH, CH, -NCc
kHxk+r)2 (1≦to≦5), -CO
A product obtained by graft polymerization of monomer G represented by OC, H, and OH.

Here, specific examples of monomer A of general formula I include β-methacryloxyethyl acid succinate, β-methacryloxyethyl acid malate, and the like.

Further, specific examples of monomer B of the general formula (2) include β-methacryloxyethyl acid phthalate and β-methacryloxyethyl acid hexahydrophthalate.

Next, specific examples of the monomer C of the general formula (3) used in the resin of 1) include stearyl, lauryl, tridecyl, 2-ethylhexyl, or hexyl ester of acrylic acid or methacrylic acid; -butyl methacrylate; cetyl methacrylate; octyl methacrylate, etc. vinyl monomers.

Examples of the monomer D having a glycidyl group used in the resin 1) or 2) include glycidyl methacrylate and glycidyl acrylate.

Next, the monomer E of the general formula (2) used in the resin of 2) is stearyl, lauryl, 2-ethylhexyl or hexyl ester of acrylic acid or methacrylic acid; t-
Examples include vinyl monomers such as butyl methacrylate; cetyl methacrylate; and octyl methacrylate.

Similarly, specific examples of the monomer F of the general formula V used in the resin 2) include methyl acrylic acid or methacrylate;
Ethyl, propyl, inzolovir, butyl or isobutyl esters: vinyl acetate: styrene; vinyltoluene;
Examples include halachlorstyrene.

Further, specific examples of the monomer G of the general formula (2) used in the resin 2] include dimethylamine or diethylamino ester of acrylic acid or methacrylic acid; hydroxy ester of acrylic acid; hydroxy ester of methacrylate; glycidyl ester of acrylate; glycidyl methacrylate ester For example,

A solution polymerization method is generally employed to produce the copolymer resin of the present invention. For example, in the case of the resin 1), monomer A of general formula (1) and/or monomer B of general formula (2) and monomer C of general formula (2) are mixed in a weight ratio of i 0.1 to 20:99.9 to 80, In the presence of a polymerization catalyst such as azobisisobutyronitrile or benzoyl peroxide in the same solvent as the carrier liquid, 7
The reaction is heated to 0 to 150°C. Then, to this reaction solution,
o, i to 20 parts by weight of monomer D having a glycidyl group to 100 parts by weight of the copolymer prepared by the above heating reaction.
70-15 in the presence of a grafting catalyst such as sulfuric acid, A-radluene sulfonic acid, or a tertiary amine compound.
The reaction may be carried out by heating to 0°C.

9- Also, when making the resin 2), monomer A of general formula I and/or monomer B of general formula (■) and monomer E of general formula (■)
and mixed at a weight ratio of 0.1 to 20:99.9 to 80,
70-15 in the presence of a polymerization catalyst in a carrier liquid and a four-glaze solvent.
Heat reaction to 0'O. Next, a monomer D having a glycidyl group was added to the reaction solution, and the copolymer 100 was added to the reaction solution.
Add 0.1 to 20 parts by weight based on part by weight, and heat the reaction mixture to 30 to 120°C in the presence of an esterification catalyst such as pyridine. Through this reaction, the copolymer is esterified, and graft active sites are formed in the esterified portion. The esterified copolymer becomes the backbone of the kraft copolymer obtained in the final step, and is obtained in a state dissolved in a solution. Furthermore, a monomer F represented by the general formula V or a monomer G represented by the general formula (2) is added to the reaction solution.

Alternatively, 1 part of 5-1001L'Ji is added to 100 parts by weight of the esterified copolymer, and 70-10-150' of these monomers are added in the presence of a polymerization catalyst such as benzoyl peroxide or azobisisobutyronitrile. The copolymer resin of the present invention can be obtained in the manner described above, but the copolymer resin of the present invention can be obtained by subjecting it to a heating reaction to form a kraft.
In the present invention, in order to improve the dispersibility of the resin and colorant, wax or polyolefin with a softening point of 60 to 130°C is added in any of the above steps, the solvent is heated to completely dissolve it, and the final step is It may be cooled. This causes the dissolved wax or polyolefin to precipitate into the liquid in the form of fine particles.

Highly insulating as a carrier liquid (electrical resistance 109Ω・m or more)
, low electric constant (dielectric constant 3 or less) petroleum-based aliphatic hydrocarbon,
Examples include n-hexane, ligroin, n-hebutane, n-pentane, isododecane, isooctane, and their halogen derivatives such as carbon tetrachloride, .dichloroethylene, and the like. Incidentally, the commercially available petroleum aliphatic hydrocarbon is Aituno e-E manufactured by Exxon.

Iso iR-Q, Aitsuno? -1. ．． Examples include Isopar H1, Isopar K, Naphtha Yo 6, and Tsurpez 100. These can be used alone or in combination.

As the coloring agent, conventionally known ones such as alkali blue, phthalocyanine green, oil blue, spirit black, cardin black, oil violet, phthalocyanine blue, benzidine yellow, methyl orange, brilliant carmine, fast red,
Examples include pigments or dyes such as methyl iolet.

The liquid developer of the present invention is prepared by adding the copolymer resin obtained as described above, 1 part by weight of this resin, 1 part by weight of colorant, and an appropriate amount of carrier liquid. (same as the non-aqueous solvent) is dispersed in a dispersing machine such as a three-roll mill, attritor, or I-lumil to obtain a concentrated toner, and then diluted with 1f4 body fluid at a constant time. A small amount of a polarity control agent may be added to the non-exploded ψ, but since the resin in the unexploded ψ has strong polarity and good dispersion stability, it is not necessary to add a polarity control agent.The present invention obtained in this way Since the visual agent uses monomer A or B as described above in the copolymer resin, the toner does not settle even after long-term storage or repeated use, and changes over time in the carrier liquid do not occur. (For example, the polarity control of the toner particles is excellent and the toner particles can be finely dispersed.) Therefore, stable and clear images can be formed at all times.

Examples of the present invention are shown below.

Example 56v of lauryl methacrylate, 4f of glycidyl methacrylate, and 0.1f of benzoyl peroxide were added to mfI of 100% of isoparaffinic hydrocarbon! After reacting at 100°C for 7 hours, the reaction solution (β-methacryloxyethyl acid succinate) 6F and 2 drops of pyridine were added and esterification was carried out at 90°C for 15 hours. with styrene lOf and benzoyl peroxide 0. OIV 3
The mixture was added over 0 minutes, and grafting was performed to obtain a copolymer resin. Next, this copolymer resin -13 = 10, Of - Dan black 2. Of, Phthalocyanine Green 0.52 and Isopar Hso,.

V and dispersed for 15 hours in a Zeel mill to obtain a concentrated toner, and this toner was further diluted 30 times with Isopar H to prepare a liquid developer for electrostatic latent images.

Comparative Example A copolymer resin was prepared in the same manner as in Example 1, except that methacrylic acid was used instead of β-methacryloxyethyl acid succinate. A liquid developer was prepared using this resin in the same manner as in the example.

Next, when each of the above-mentioned developers was placed in a commercially available wet development transfer type electrophotographic copying machine and continuous copying was performed, the product of the present invention showed no deterioration during use compared to the comparative product, and had a high density. A clear image was formed.

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Claims (1)

[Claims] 1. A liquid developer for electrostatic latent images comprising a colorant and a resin dispersed in a carrier liquid, wherein the resin has the general formula I, I C12=C-COO(CH,) n0CO (OH,)
m C00H (where RFi, H or CH, group, n and m each represent an integer of 1 to 3) Monomer A represented by
, n is a copolymer resin containing as a constituent unit at least one monomer selected from the group consisting of monomers B represented by developer.