JPH05257324A - Electrophotographic toner - Google Patents

Abstract

PURPOSE:To provide the electrophotographic toner superior in compatibility with a polyester-based resin, stable in triboelectrification amount and rapid in its rising, sharp and even in its distribution, and controllable to its suitable electrification amount to the system to be used. CONSTITUTION:The polyester resin to be used is characterized by containing a charge controller of a white or substantially colorless compound excellent in the compatibility with the resin, superior in mechanical friction and impact resistance, and in stability against temperature and humidity, and represented by the formula in which each of R1 and R4 is an optionally substituted aromatic ring including a condensed ring; each of R2 and R3 is H, an alkyl, or an optionally substituted aromatic ring; M is a trivalent metal; and X<n+> is a cation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner for developing an electrostatic latent image in electrophotography, and more specifically, an electrophotographic toner using a charge control agent having excellent compatibility with a toner resin. Regarding

[0002]

2. Description of the Related Art In electrophotography, an electrostatic latent image is formed on a photoconductor made of a photoconductive substance and developed by a powder developer to be visualized, and further, heat or a solvent, and in some cases, a latent image. The method of fixing on paper with pressure is common. As such an electrophotographic developer, a two-component developer of a mixture of a toner in which a colorant, a charge control agent, a fluidizing agent, etc. are dispersed in a natural resin or a synthetic resin and a carrier of iron powder or ferrite powder is used. , A natural resin or a synthetic resin, and a colorant, a charge control agent, a fluidizing agent, and a one-component developer of a magnetic material.

The two-component type developer achieves the development by adhering the toner charged by friction with the carrier to the electrostatic latent image. As a one-component type developer, it has been conventionally used instead of the carrier. In addition, a toner that is charged by friction with a brush-shaped or plate-shaped friction member having a similar function is known, and recently, a magnetic powder has been kept in a dispersed state and has a mutual interaction with the magnetic powder. Toners that become charged by friction have become known. The photoconductor layer can be positively or negatively charged so that exposure under the original gives a positive or negative electrostatic latent image. The developing toner is kept positive or negative depending on the polarity of the electrostatic latent image.

In order to maintain the electric charge in the toner, it has been proposed to utilize the triboelectric chargeability of the resin which is the main component of the toner, but in this method, the electric charge of the toner is small and the solid surface resistance value is large. Therefore, the obtained image is easily fogged,
It becomes unclear. Therefore, in order to impart desired triboelectric charging properties to the toner, dyes and pigments that impart an electric charge, and dyes and pigments called charge control agents have been added, which have been put into practical use in the technical field today. ing.

However, dyes and pigments as charge control agents have a complicated structure and poor stability, and are decomposed or deteriorated by, for example, mechanical friction and impact, temperature and humidity changes, electrical impact and light irradiation. Therefore, the charge adjusting ability is easily lost. Further, since it is a colored substance, it has an essential defect that it cannot be used for toner having a specific hue.

Further, many of these dyes and pigments have poor compatibility with the resin for toner and thus have poor dispersibility.
When melted and kneaded and then pulverized, the components in the obtained individual toner particles become non-uniform, the charge amount on the toner surface is biased, and in some cases even particles consisting only of dyes or pigments are present. As a result, fogging occurs in the obtained image, quality is deteriorated with the number of times of copying, toner is scattered around the edge of the latent image, and carrier contamination is caused.

[0007]

SUMMARY OF THE INVENTION A general object of the present invention is to provide a new technique relating to charge control of a toner which overcomes the above problems, has excellent compatibility with a polyester resin, and is triboelectrically charged. The amount is stable and the start-up is good,
Another object of the present invention is to provide a toner having a sharp triboelectric charge amount distribution and a uniform charge amount that can be controlled to a charge amount suitable for a system used. Another object is to provide a stable chromatic color toner that reproduces a stable image that is not affected by changes in temperature and humidity. Another object of the present invention is to provide a toner having excellent long-term storage stability, maintaining initial characteristics even during continuous copying, and showing no deterioration in charging characteristics.

[0008]

The present inventors have found that among the resin components for toners, the compatibility with polyester resins is very good, and they have thermal stability up to a temperature at which melt-kneading is sufficient, and are colorless. The present invention has been completed by discovering a compound that is capable of imparting an appropriate negative charge to the toner.

That is, the present invention is a toner for electrophotography, which comprises a compound represented by the general formula <A> as a charge control agent in a polyester resin.

[0010]

[Chemical 1]

In the formula, R ₁ and R ₄ represent a substituted or unsubstituted aromatic ring (including condensed ring), R ₂ and R ₃ are hydrogen atoms,
An alkyl group, a substituted or unsubstituted aromatic ring (including a condensed ring) is shown, M is a trivalent metal, and X ^{n +} is a cation.

Regarding the compound represented by the general formula <A>,
The details will be described below. Examples of the aromatic ring of R ₁ , R ₂ , R ₃ and R ₄ include a benzene ring and a naphthalene ring, and the substituents are an alkyl group, an alkenyl group, an alkoxy group, a halogen atom, an aryl group, an aralkyl group and a nitro group. Group, amino group, cyan group, hydroxyl group, etc., and as the alkyl group of R ₂ and R ₃ , methyl group, ethyl group, n-butyl group, t-butyl group, iso-amyl group, n-dodecyl group. , N−
Examples include octadecyl group and cyclohexyl group.

Further, M is a trivalent metal such as Cr or A.
l, Fe, Co, Ti, B and the like.

Various inorganic cations and organic cations are used as X ^{n +} . The inorganic cations include hydrogen ions and metal ions, and the monovalent or divalent metal ions include Li ⁺ , Na ⁺ , K ⁺ , Mg ²⁺ , Ca ²⁺ and Z.
^Examples include n ²⁺ and Ba ²⁺ . Examples of the organic cation include ammonium ion, iminium ion, phosphonium ion and the like.

Preferred among the above organic cations are those represented by the following general formula <B>, <C>, <D> or <E>.

[0016]

[Chemical 2]

In the formula, R ₅ , R ₆ , R ₇ , R ₈ , R ₉ , R ₁₀ ,
R ₁₁ , R ₁₂ , R ₁₃ , R ₁₄ and R ₁₅ each represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, and Z ₁ and Z ₂ are each represented by The non-metallic atomic group which couple | bonds with a nitrogen atom and forms a 5-membered ring or 6-membered ring is shown.

Examples of the alkyl group include methyl group, ethyl group, n-butyl group, t-butyl group, iso-amyl group, n-dodecyl group, n-octadecyl group and cyclohexyl group. Examples of the aryl group include a phenyl group and an α-naphthyl group. These alkyl groups or aryl groups include an alkyl group, an aralkyl group, a halogen atom,
It may be substituted with various substituents such as an alkoxy group, a hydroxyl group, a cyano group and an aryl group. Examples of Z ₁ and Z ₂ include non-metal atom groups necessary for forming various heterocycles such as a pyridine ring, an isoquinoline ring, a pyrrole ring, an imidazole ring, a piperidine ring and a pyrrolidine ring.

Specific examples of the compound represented by formula <A> are shown below. The compound No. is commonly used in the examples.

[0020]

[Chemical 3]

[0021]

[Chemical 4]

[0022]

[Chemical 5]

[0023]

[Chemical 6]

[0024]

[Chemical 7]

The compound represented by the general formula <A> used as the charge control agent of the present invention is, for example, the following general formula <F>, <G> (wherein R ₁ , R ₂ ,
R ₃ and R ₄ are easily obtained by adding and reacting a compound represented by the general formula <A>.

[0026]

[Chemical 8]

The compound represented by the general formula <A> added to the toner component is generally 0.1 to 100 parts by weight of the resin.
It is 10 parts by weight, preferably 0.5 to 5 parts by weight.

As the polyester resin used in the toner of the present invention, for example, ethylene glycol, 1,2-
Propylene glycol, 1,4-butanediol, 1,4
-Butenediol, neopentyl glycol, 1,6-
Hexanediol, 3,3,5-trimethyl-2,4-pentanediol, diethylene glycol, dipropylene glycol, triethylene glycol, bisphenol A, hydrogenated bisphenol A, bisphenol A ethylene oxide adduct, bisphenol A propylene oxide adduct, Polyhydric alcohols such as glycerin, trimethylolethane and trimethylolpropane, and maleic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid, glutaconic acid, glutaric acid, phthalic acid, isophthalic acid, terephthalic acid, hexahydrophthalic acid Acid, cyclohexadicarboxylic acid, succinic acid, n-butylsuccinic acid, n
-Dodecenyl succinic acid, adipic acid, azelaic acid, sebacic acid, malonic acid, linoleic acid, 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 2 , 5,
7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,5-hexanetricarboxylic acid,
1,2,4-butanetricarboxylic acid, 1,3-dicarboxy-2-methylcarboxypropane, 1,2,7,8-octanetetracarboxylic acid and polycarboxylic acids such as their acid anhydrides A polymer obtained by condensation is used.

In addition to the above polyester resin, styrene resin, styrene-acrylic resin, styrene-butadiene resin, epoxy resin, paraffin wax, polyethylene, etc. are known in consideration of adhesiveness, storability, fluidity, crushability and the like. One or several types of the toner resins may be mixed and used. As the colorant, a large number of known dyes and pigments are used, but as particularly excellent toners for color copying, benzidine yellow, quinacdrine,
Examples thereof include copper phthalocyanine blue and copper phthalocyanine green.

The toner of the present invention is usually mixed with a carrier to provide a two-component developer, but of course it can be used as a one-component developer.

[0031]

The present invention will be described in detail below with reference to examples. In addition, "part" in an Example represents a weight part.

Example 1 100 parts of polyester resin, 6 parts of carbon black and N
The premix was prepared by uniformly premixing 2 parts of the compound shown in o.1 with a ball mill. Then, after heating, melting, kneading, cooling, coarse pulverization with a vibration mill and fine pulverization with a jet mill, a black toner having a particle size of 8 to 15 μm was obtained. 95 parts of an iron powder carrier was mixed with 5 parts of the obtained toner to prepare a developer. The initial blow-off charge amount of this developer was −23.0 μC / g, and the rising time was 29 seconds. When a toner image was formed on the commercially available selenium drum of this developer by a magnetic brush developing method, a clear image without fog was obtained. With this toner, the copy quality did not deteriorate even after 10,000 continuous copies.

Example 2 100 parts of a polyester resin, 6 parts of a yellow dye (CI Disperse Yellow 33) and 2 parts of a compound represented by No. 2 were treated in the same manner as in Example 1 to obtain a yellow toner. .. The initial blow-off charge amount of the developer prepared from the obtained yellow toner in the same manner as in Example 1 was −25.5 μC / g, and the rising time was 30 seconds. When this developer was copied in the same manner as in Example 1, a clear yellow image without fog was obtained.
With this toner, the copy quality did not deteriorate even after 10,000 continuous copies.

Example 3 100 parts of polyester resin, 8 parts of red dye (C.I. Pigment Red 12) and 2 parts of the compound represented by No. 3 were treated in the same manner as in Example 1 to obtain a red toner. The developer prepared in the same manner as in Example 1 from the obtained red toner has an initial blow-off charge amount of −31.3 μC / g and a rising time of
It was 28 seconds. When this developer was copied in the same manner as in Example 1, a clear red image without fog was obtained. With this toner, the copy quality did not deteriorate even after 10,000 continuous copies.

Example 4 100 parts of polyester resin, 6 parts of blue dye (C.I. Pigment Blue 15) and 2 parts of the compound represented by No. 4 were treated in the same manner as in Example 1 to obtain a blue toner. The developer prepared in the same manner as in Example 1 from the obtained blue toner had an initial blow-off charge amount of −32.5 μC / g and a rising time of
It was 33 seconds. When this developer was copied in the same manner as in Example 1, a clear blue image without fog was obtained. With this toner, the copy quality did not deteriorate even after 10,000 continuous copies.

Example 5 In Example 1, instead of the compound represented by No. 1, N was used.
A black toner was obtained in the same manner as in Example 1 except that the compound shown in Table 5 was used. The developer prepared from the obtained black toner in the same manner as in Example 1 had an initial blow-off charge amount of −28.9 μC / g and a rising time of 31 seconds.

Example 6 Instead of the compound represented by No. 2 in Example 2, N was used.
A yellow toner was obtained in the same manner as in Example 2 except that the compound shown in o.6 was used. The initial blow-off charge amount of the developer prepared from the obtained yellow toner in the same manner as in Example 1 was −27.2 μC / g, and the rising time was 30 seconds.

Example 7 Instead of the compound shown in No. 3 in Example 3, N was used.
A red toner was obtained in the same manner as in Example 3 except that the compound shown in o.7 was used. The developer prepared from the obtained red toner in the same manner as in Example 1 had an initial blow-off charge amount of −35.5 μC / g and a rising time of 26 seconds.

Example 8 Instead of the compound shown in No. 4 in Example 4, N was used.
A blue toner was obtained in the same manner as in Example 4 except that the compound shown in 0.8 was used. The developer prepared from the obtained blue toner in the same manner as in Example 1 had an initial blow-off charge amount of −25.1 μC / g and a rising time of 29 seconds.

Example 9 Instead of the compound represented by No. 1 in Example 1, N was used.
A black toner was obtained in the same manner as in Example 1 except that the compound represented by 0.9 was used. The developer prepared from the obtained black toner in the same manner as in Example 1 had an initial blow-off charge amount of −23.5 μC / g and a rising time of 35 seconds.

Example 10 Instead of the compound represented by No. 2 in Example 2, N was used.
A yellow toner was obtained in the same manner as in Example 2 except that the compound shown in o.10. The developer prepared from the obtained yellow toner in the same manner as in Example 1 had an initial blow-off charge amount of −31.1 μC / g and a rising time of 32 seconds.

Example 11 Instead of the compound represented by No. 3 in Example 3, N was used.
A red toner was obtained in the same manner as in Example 3 except that the compound shown in o.11. The developer prepared from the obtained red toner in the same manner as in Example 1 had an initial blow-off charge amount of −26.8 μC / g and a rising time of 27 seconds.

Example 12 Instead of the compound shown in No. 4 in Example 4, N was used.
A blue toner was obtained in the same manner as in Example 4 except that the compound shown in o.12. The developer prepared from the obtained blue toner in the same manner as in Example 1 had an initial blow-off charge amount of −30.6 μC / g and a rising time of 34 seconds.

Example 13 In Example 1, instead of the compound represented by No. 1, N
A black toner was obtained in the same manner as in Example 1 except that the compound shown in o.13 was used. A developer prepared from the obtained black toner in the same manner as in Example 1 had an initial blow-off charge amount of -31.1 μC / g and a rising time of 28 seconds.

Comparative Example 1 Example 1 was repeated except that a conventional zinc salicylate compound was used in place of the compound represented by No. 1 in Example 1.
A black toner was obtained in the same manner as in. The initial blow-off charge amount of the developer prepared from the obtained black toner in the same manner as in Example 1 was −20.5 μC / g, and the rising time was 1 minute 2 seconds. When this developer was copied in the same manner as in Example 1, remarkable fog occurred and a clear image could not be obtained.

Comparative Example 2 A red toner was obtained in the same manner as in Example 3 except that the conventional CI Solvent Red 177 was used in place of the compound represented by No. 3 in Example 3. The developer prepared in the same manner as in Example 1 from the obtained red toner had an initial blow-off charge amount of −25.3 μC / g and a rise time of 1
It was 15 minutes. When this developer was continuously copied in the same manner as in Example 1, significant image fog, toner scattering, carrier contamination, etc. were observed after 5,000 sheets.

[0047]

EFFECT OF THE INVENTION The charge control agent used in the present invention has extremely good compatibility with a polyester resin, excellent mechanical friction and impact stability, temperature and humidity stability, etc., and is white or substantially colorless. Since it does not affect the coloring of the colorant, an electrophotographic toner having a clear image and capable of continuous use (color electrophotographic toner) can be obtained.

Claims (1)

[Claims] 1. A toner for electrophotography, comprising a compound represented by the general formula <A> as a charge control agent in a polyester resin. [Chemical 1] (In the formula, R ₁ and R ₄ represent a substituted or unsubstituted aromatic ring (including a condensed ring), R ₂ and R ₃ represent a hydrogen atom, an alkyl group, a substituted or unsubstituted aromatic ring (including a condensed ring) ), M represents a trivalent metal, and X ^{n +} represents a cation.)