JP2572759B2 - Toner for electrostatic image development - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial application field> The present invention relates to a toner for developing an electrostatic image used in an electronic copying machine or the like.

<Prior Art> A developer used in an electronic copying machine or the like is once adhered to an image carrier such as a photoconductor on which an electrostatic image is formed in a development process, and then is transferred to a photoconductor in a transfer process. Is transferred to the transfer paper, and is fixed on the copy paper surface in a fixing step. At that time, as a developer for developing an electrostatic image formed on the latent image holding surface, a two-component developer composed of a carrier and a toner and a one-component developer (magnetic toner) that does not require a carrier It has been known.

Conventionally, a charge controlling agent such as a nigrosine dye, a quaternary ammonium salt or the like, a carrier coating agent, and the like have been known as those which impart a charge to the developer.

<Problems to be Solved by the Invention> However, with these conventional charging agents, the charging effect is not sufficient, and copy stains due to continuous copying occur,
There is a problem that the copy quality is deteriorated.

<Means for Solving the Problems> The inventors of the present invention have conducted intensive studies to provide a high-quality electrostatic image developing toner free from copy contamination and the like. The inventors have found that these problems can be solved by incorporating an enhancer into the toner, and have reached the present invention.

That is, the gist of the present invention is at least a colorant, a resin,
And a toner for developing an electrostatic image comprising at least one charge control agent selected from the group consisting of a nigrosine dye, a quaternary ammonium salt, a polyamine resin, and an amino group-containing styrene resin, wherein the toner has the following general formula: The toner for developing electrostatic images comprises at least one kind of the charge improver represented by (I).

(In the above formula, R ₁ and R ₂ represent a hydrogen atom, an alkyl group, a phenyl group or an alkylphenyl group, and R ₃ represents a hydrogen atom, a hydroxyl group or (R ₁ and R ₂ are as described above). Hereinafter, the present invention will be described in detail.

Various known resin components can be used as the resin component of the toner of the present invention.

That is, styrene resin, styrene-acrylic resin,
Examples include addition polymerization type resins such as styrene-butadiene resin and acrylic resin, condensation polymerization type resins such as polyester resin and polyamide resin, and epoxy resin.

Among these resins, monomers for forming the addition polymerization type resin include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-ethylstyrene, 2,4- Dimethylstyrene, p
-N-butylstyrene, p-tert-butylstyrene, p
-N-hexylstyrene, pn-octylstyrene,
pn-nonylstyrene, pn-decylstyrene, p
-N-dodecylstyrene, p-methoxystyrene, p-
Styrenes such as phenylstyrene, p-chlorostyrene and 3,4-dichlorostyrene; ethylene, propylene,
Ethylenically unsaturated monoolefins such as butylene and isobutylene; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide and vinyl fluoride; vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate and vinyl butyrate Classes: methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate,
Dodecyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, α-chloromethyl acrylate, methyl methacrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, N-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylamino methacrylate Α-methylene aliphatic monocarboxylic acid esters such as ethyl and diethylaminoethyl methacrylate; acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile and acrylamide; Vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone; N-vinyl pyrrole, N-vinyl carbazole, N-vinyl isodol, N- N-vinyl compounds such as vinylpyrrolidone; monoolefin monomers such as vinylnaphthalenes;
Diolefin-based monomers such as propadiene, butadiene, isoprene, chlorobrene, pentadiene and hexadiene can be exemplified. These monomers can be used alone or in combination of two or more.

Further, as the monomer for forming the condensation polymerization type resin, ethylene glycol, triethylene glycol, 1,
2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol,
1,4-butenediol, 1,4-bis (hydroxymethyl)
Polyhydric alcohols such as cyclohexane, bisphenol A, hydrogenated bisphenol A, polyoxyethylated bisphenol A, and polyoxypropylene bisphenol A, ethylenediamine, tetramethylenediamine, bentamethylenediamine, piperazine, hexamethylenediamine, etc. Polyamines and maleic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, malonic acid, or Examples thereof include esters with acid anhydrides or lower alcohols, and polycarboxylic acids such as dimers of linoleic acid.

The colorant used in the present invention is not particularly limited as long as it is conventionally used,
Preferably, a carbon black is used.

Incidentally, the toner of the present invention contains a charge control agent as in the conventional product. Nigrosine dyes as charge control agents,
A quaternary ammonium salt, a polyamine resin, an amino group-containing styrene resin, or the like is used.

In the present invention, the toner containing the above components needs to further contain a charge improver represented by the following general formula (I).

(In the above formula, R ₁ and R ₂ represent a hydrogen atom, an alkyl group, a phenyl group or an alkylphenyl group, and R ₃ represents a hydrogen atom, a hydroxyl group or (R ₁ and R ₂ are as described above). As the alkyl group, a lower alkyl group such as a methyl group, an ethyl group, and a propyl group is preferable, and as the alkylphenyl group, a substituted phenyl group substituted with at least one of the above alkyl groups is preferable.

Specific examples of the above-described charge improver include 1,4-bis (p-toluidino) anthramonone, 1-methylamino-anthraquinone, 1- (p-toluidino) -4-hydroxyanthraquinone, and the like.

The charge improver of the present invention is preferably used as one or more of these, preferably as a mixture of the above three compounds.

The amount of the charge improver is 0.01 to 100 parts by weight of the toner.
It is preferably from 10 to 10 parts by weight, preferably from 0.1 to 5 parts by weight. If the amount of the charge improver is less than the above range, the effect of improving the chargeability is not improved, and if the amount is more than the above range, the quality of the toner is undesirably deteriorated. Further, it is preferable to treat the colorant used in the present invention with a metal salt of a carboxylic acid, since the copy quality can be further improved.

Such metal salts of carboxylic acids include formic acid, acetic acid,
Propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid,
Al, Mg, Zn, Ca, Ba of fatty acids having a linear structure such as heptadecylic acid, stearic acid, nonadecanoic acid, arachic acid, behenic acid, lignoceric acid, cerotic acid, heptacosanoic acid, montanic acid, melisylic acid, and lacceric acid Metal salts such as Pb, Pb;
Al of unsaturated fatty acids such as acrylic acid, crotonic acid, isocrotonic acid, undecylenic acid, oleic acid, elaidic acid, centreic acid, erucic acid, brassic acid, sorbic acid, linoleic acid, arachidonic acid, propiolic acid, and stearolic acid , Mg, Zn, Ca, Ba, Pb, etc .; metal salts such as abietic acid, bimalic acid, benzoic acid, and cinnamic acid; , Zn, Ca, Ba, Pb and other metal salts. As an example of a method of treating a metal salt of a carboxylic acid on the surface of a colorant, an aqueous alkali solution of a base acid is added to an aqueous suspension of the colorant, mixed, and then a metal salt solution containing a necessary metal. The metal salt of the desired carboxylic acid can be precipitated on the surface of the colorant particles by adding the carboxylic acid. Then, it may be purified, dried and crushed to adjust the particle size.

In the present invention, the metal salt of a carboxylic acid is preferably contained in an amount of about 0.5 to 25% by weight, preferably 1 to 15% by weight, based on the colorant. Further, the softening point of the metal salt of carboxylic acid is preferably in the range of 70 to 250 ° C, preferably 100 to 200 ° C. If the softening point is 70 ° C. or lower, the toner tends to aggregate and fuse during continuous use, and a filming phenomenon tends to occur on the surface of the photoconductor, which is not preferable.

In addition, additives such as a low-molecular-weight olefin polymer and finely divided silica may be included as a toner component of the present invention in order to improve fixability and fluidity.

The toner may be produced by kneading the above components in a kneader, cooling, pulverizing and classifying. Further, the toner of the present invention can be applied to a so-called one-component developer (magnetic toner) such as an encapsulated toner, a polymerized toner, and a magnetite-containing toner, in addition to a two-component developer.
The average particle size of the toner is preferably 5 to 20 μm. The carrier for forming the developer by mixing with the toner of the present invention is not particularly limited, but iron powder having an average particle diameter of 10 to 200 μm is preferable. The particle size of the iron powder is not particularly limited. In this case, a so-called coating carrier coated with a fluorine-based resin or the like can be used for the purpose of improving durability during continuous use. Further, ferrite-based or magnetite-based iron powder can also be used.

<Examples> Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof.

 In the examples, “parts” indicates “parts by weight”.

<Example 1> Were kneaded and kneaded and crushed and classified to obtain a black toner having an average particle diameter of 11 μm.

5 parts of this toner and 100 parts of a fluorine-based resin coating carrier having an average particle size of about 100 μm were mixed and stirred to prepare a developer. Next, when this developer was actually photographed by a copying machine using an organic photoconductor as a photoconductor, a white background was stained,
A clear copy with little so-called fog was obtained.

<Example 2> A toner was formed in the same manner as in Example 1 except that the amount of 1,4-bis (p-toluidino) anthraquin used was changed to 3 parts. A clear copy was obtained.

Example 3 Instead of 1,4-bis (p-toluidino) anthraquinone as a charge improver Except that 1 part of 1-methylamino-anthraquinone was used, a toner was formed in the same manner as in Example 1, and a real copy was obtained. As in Example 1, a clear copy with little fog was obtained.

Example 4 Instead of 1,4-bis (p-toluidino) anthraquinone as a charge improver A toner was formed in the same manner as in Example 1 except that 1 part of 1- (p-toluidino) -4-hydroxyanthraquinone was used.

Example 5 One part of 1,4-bis (p-toluidino) anthraquinone, 1 part of 1-methylaminoanthraquinone and a part of 1- (p-toluidino) -4-hydroxyanthraquinone are used as charge improvers. Other than the above, a toner was formed in the same manner as in Example 1, and a copy was obtained with clear fog at the place where the image was actually taken.

<Comparative Example 1> A toner was obtained in the same manner as in Example 1 except that 1,4-bis (p-toluidino) anthraquinone was not used as a charge improver, and a real copy was obtained. Was done.

<Effect of the Invention> The toner for developing an electrostatic image of the present invention is a high quality toner for developing an electrostatic image, which does not cause a copy stain or the like in continuous copying.

Claims (7)

(57) [Claims] 1. An electrostatic image comprising at least a colorant, a resin, and at least one charge control agent selected from the group consisting of a nigrosine dye, a quaternary ammonium salt, a polyamine resin, and an amino group-containing styrene resin. A toner for developing an electrostatic charge image, wherein the toner contains at least one kind of a charge improver represented by the following general formula (I). (In the above formula, R ₁ and R ₂ represent a hydrogen atom, an alkyl group, a phenyl group or an alkylphenyl group, and R ₃ represents a hydrogen atom, a hydroxyl group or (R ₁ and R ₂ are as described above). ). 2. The method according to claim 1, wherein the charge improver is used in an amount of 0.0
2. The toner according to claim 1, wherein the toner is contained in an amount of 1 to 10 parts by weight. 3. The toner according to claim 1, wherein the charge improver is 1,4-bis (p-toluidino) anthraquinone. 4. The toner according to claim 1, wherein the charge improver is 1-methylamino-anthraquinone. 5. The method of claim 1, wherein the charge improver is 1- (p-toluidino) -4.
2. The electrostatic image developing toner according to claim 1, wherein the toner is hydroxyanthraquinone. 6. A patent wherein the charge improver is a mixture of 1,4-bis (p-toluidino) anthraquinone, 1-methylamino-anthraquinone and 1- (p-toluidino) -4-hydroxyanthraquinone. The toner for developing an electrostatic image according to claim 1. 7. The toner for developing an electrostatic image according to claim 1, wherein the colorant is carbon black.