JP2002006541A - Electrophotographic toner and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic toner which is superior in heat- resistant stability and showing sufficient fixing performance. SOLUTION: The electrophotographic toner contains at least a resin and wax, the resin is a condensation resin, such as polyester resin or the like, and the wax is encapsulated in the toner particles and present locally close to the surface of the particles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic toner used in technical fields such as electrophotography, electrostatic recording and electrostatic printing, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, styrene resins, dry toners used for electrophotography, electrostatic recording, electrostatic printing, and the like have been used.
A toner binder such as polyester is melt-kneaded together with a coloring agent or the like and finely pulverized. These dry toners are developed and transferred onto paper or the like, and then heated and melted using a hot roll. At that time, if the temperature of the hot roll is too high, there is a problem (hot offset) that the toner is excessively melted and fused to the hot roll.

On the other hand, if the temperature of the hot roll is too low, there is a problem that the toner does not melt sufficiently and the fixing becomes insufficient. In recent years, from the viewpoint of increasing the image forming speed, saving energy, and reducing the size of copiers and the like, there has been a demand for a toner that does not have any problem with hot offset resistance and that can be fixed at a lower temperature.

[0004] Further, it is necessary to have heat resistance stability such that the toner does not aggregate during storage and at ambient temperature in the apparatus. Particularly in full-color copying machines and full-color printers, since the gloss and color mixing properties of the images are required, the toner must have a lower melt viscosity, and a sharp-melt polyester toner binder is used. ing.

[0005] Since hot offset tends to occur in such a toner, silicone oil or the like is conventionally applied to a heat roll in a full-color device. However, in this method, it is inevitable that oil adheres to copy paper, an OHP film, or the like. In particular, in OHP, there is a problem in that the color tone is deteriorated by the adhered oil. In order to solve this problem by reducing the amount of silicone oil applied, there is a general method of dispersing wax as a release agent in the toner. However, a wax having a low softening point is present on the outer surface of the toner particles. As a result, there has been a problem in heat stability.

On the other hand, in recent years, there has been an increasing need for a toner having a small particle size in order to improve image quality and improve resolution. However, since the toner obtained by the conventional pulverization method has an irregular shape, when the particle size is small, the fluidity of the powder becomes insufficient, and it becomes difficult to supply the toner to the developing device, and the transferability becomes poor. The problem of exacerbation arises. Furthermore, because of the irregular shape, the shearing force caused by stirring in the developing box causes a problem that a part of the toner particles is broken, and the generated fine powder contaminates the surface of the carrier and adversely affects the charging of the toner. .

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the conventional toner, and to provide excellent low-temperature fixability, heat resistance stability, hot offset resistance, powder fluidity and durability. It is another object of the present invention to provide a toner for electrophotography which is excellent in quality and a method for producing the same.

[0008]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, the present invention relates to an electrophotographic toner containing at least a resin and a wax, wherein the resin is a condensation resin. An electrophotographic toner characterized in that wax is included in toner particles and is localized near the surface of the particles, and is excellent in toner suitability such as low-temperature fixability, heat stability, and hot offset resistance. Having found this, the present invention has been completed.

That is, the present invention provides: An electrophotographic toner including at least a resin and a wax, wherein the resin is a condensation resin, and the wax is included in the toner particles and is localized near the surface of the particles. 2. 2. The electrophotographic toner according to claim 1, wherein the condensation resin is a polyester resin. 3. The toner for electrophotography according to claim 2, wherein the polyester resin is a polyester resin having a non-polar group in a molecule. The acid value of the polyester resin is 5-100 mgKOH
4. The toner for electrophotography according to any one of claims 1 to 3, wherein 5. The electrophotographic toner according to claim 1, wherein the toner is spherical. A method for producing a spherical toner for electrophotography, comprising: dispersing a molten resin of a wax, a condensation resin, and a pigment in high-temperature water while maintaining the molten state of the resin, cooling, and then drying. , 7. 7. The method according to claim 6, wherein the condensation resin is a polyester resin.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. In the electrophotographic toner of the present invention, the resin is a condensation resin,
The wax is included in the toner particles and is localized near the surface of the particles. This toner has excellent heat stability because wax, which is a substance having a low softening point, is included in the toner particles, and shows sufficient fixing performance because the wax is localized on the particle surface. Use of such a toner has the effect of enabling clearer and more stable printing.

The condensation resin used in the present invention refers to a resin containing a bond by a condensation reaction, and specific examples thereof include a polyester resin (A), a modified polyester resin, a urethane resin, and a urea resin. . Among them, a polyester resin or a modified polyester resin is preferable from the viewpoint of charging characteristics as a toner.
Hereinafter, a polyester resin or a modified polyester resin will be described as the condensation resin.

The modified polyester resin may be modified in the following manner: [1] a modification in which a nonpolar group is introduced into the polyester resin, [2] a modification in which a urethane bond is introduced, and [3] a urea bond. Modification, etc., to give a nonpolar group-modified polyester resin (B), a urethane-modified polyester resin (C), and a urea-modified polyester resin (D), respectively.

These modified resins are prepared by known and commonly used raw materials and production methods. Raw materials used at that time can be used without particular limitation as long as they are known and commonly used raw materials constituting these resins. As for the modified form of the polyester resin (A), [1], [2], and [3] may be used alone or in combination.

The raw material used for the polyester resin (A) used in the present invention can be any known raw material constituting the polyester resin without any particular limitation. Typical raw materials used are:
(A) a polybasic acid such as a dicarboxylic acid and a polybasic acid compound such as an anhydride thereof or a lower alkyl ester thereof; and (b) a polyhydric alcohol such as a diol.

The dicarboxylic acid serving as the component (a) includes:
Maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, oxalic acid, malonic acid, succinic acid, succinic anhydride, n-dodecenyl succinic acid and anhydride thereof,
Isododecenyl succinic acid and its anhydride, n-dodecyl succinic acid and its anhydride, isododecyl succinic acid and its anhydride, n-octyl succinic acid and its anhydride, n-octynyl succinic acid and its anhydride, n-
Aliphatic dibasic acids such as butylsuccinic acid and its anhydride, adipic acid, azelaic acid, sebacic acid, decane-1,10-dicarboxylic acid;

Phthalic acid, phthalic anhydride, tetrahydrophthalic acid and its anhydride, hexahydrophthalic acid and its anhydride, tetrabromophthalic acid and its anhydride,
Tetrachlorophthalic acid and its anhydride, hetic acid and its anhydride, hymic acid and its anhydride, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid,
Aromatic or alicyclic dibasic acids such as 2,6-naphthalenedicarboxylic acid;

Further, a carboxylic acid having three or more carboxyl groups in one molecule and a reactive derivative thereof can be used as one of the starting materials having three or more functional groups. Typical examples thereof include trimellitic acid, trimellitic anhydride, methylcyclohexentricarboxylic acid, methylcyclohexentricarboxylic anhydride, pyromellitic acid, pyromellitic anhydride and the like.

These polybasic acids or acid anhydrides may be used alone or in combination of two or more.

Further, as the above-mentioned polybasic acids, those in which a part or all of the carboxyl group is an alkyl ester, an alkenyl ester or an aryl ester can be used.

Next, typical examples of the polyhydric alcohol serving as the component (b) include ethylene glycol, 1,2,
-Propylene glycol, 1,4-butanediol,
1,5-pentanediole, 1,6-hexanediol-
, Diethylene glycol, dipropylene glycol,
Aliphatic diols such as triethylene glycol and neopentyl glycol;

Bisphenols such as bisphenol A and bisphenol F; alkylene oxide adducts of bisphenol A such as ethylene oxide adduct of bisphenol A and propylene oxide adduct of bisphenol A; Aralkylene glycols such as xylylene diglycol, cyclohexane dimethanol and hydrogenated bisphenol A; or alicyclic diols.

A compound having three or more hydroxyl groups can also be used as one of the trifunctional or higher functional raw materials, and typical examples thereof include glycerin, trimethylolethane, trimethylolpropane, sorbitol, and the like. 1,
2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol,
There are 2-methylpropanetriol, 1,3,5-trihydroxybenzene, tris (2-hydroxyethyl) isocyanurate and the like.

Further, a compound having both a hydroxyl group and a carboxyl group in one molecule, such as hydroxy acid or 6-hydroxyhexanoic acid as a trifunctional raw material component such as dimethylolpropionic acid or dimethylolbutanoic acid, or Their reactive derivatives can also be used as polyhydric alcohols.

These polyhydric alcohols may be used alone or in combination of two or more.

The non-polar group-modified polyester resin (B) used in the present invention includes (a) a polybasic acid compound such as a polybasic acid such as dicarboxylic acid and an anhydride thereof or a lower alkyl ester thereof; and b) a reaction product of a polycondensate with a polyhydric alcohol such as a diol and (c) a compound having a non-polar group. Examples of the compound having a nonpolar group as the component (c) include a monocarboxylic acid having a nonpolar group, a monoalcohol having a nonpolar group, and a monoepoxy compound having a nonpolar group. Of these, monoepoxy compounds are preferred in view of the ease of forming spherical particles. As raw materials (a) and (b)
When only (a) and / or (b) are used, they only need to be compounds having a non-polar group.

Examples of the monocarboxylic acid having a nonpolar group include aliphatic monocarboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, lauric acid, palmitic acid, stearic acid, oleic acid, coconut oil fatty acid and palm oil fatty acid;

Aromatic or alicyclic monocarboxylic acids such as benzoic acid, p-tert-butylbenzoic acid and cyclohexanecarboxylic acid;

Examples of the monoalcohol having a non-polar group include aliphatic monoalcohols such as methyl alcohol, ethyl alcohol, n-butyl alcohol, p-tert-butyl alcohol, n-dodecyl alcohol and n-octadecyl alcohol;

Aromatic or alicyclic monoalcohols such as benzyl alcohol and cyclohexanol;

Examples of the monoepoxy compound having a non-polar group include phenyl glycidyl ether, alkyl phenyl glycidyl ether, alkyl glycidyl ether, alkyl glycidyl ester, glycidyl ether of phenol alkylene oxide adduct, α-olefin oxide, and monoepoxy fatty acid alkyl ester. And the like.

Examples of the alkyl phenyl glycidyl ether include phenyl glycidyl ether, cresyl glycidyl ether, nonylphenol glycidyl ether, and butylphenol glycidyl ether. Examples of the alkyl glycidyl ether include butyl glycidyl ether and 2-ethylhexyl glycidyl ether. As a commercially available product of alkyl glycidyl ester, "Kajura E10"
(Monoglycidyl esters of branched fatty acids manufactured by Shell Chemical Company).

The glycidyl ether of an alkyl phenol or alkylene oxide adduct is, for example, a glycidyl ether of an adduct of an alkylene oxide such as ethylene oxide or propylene oxide to a lower alkyl phenol such as butyl phenol; a glycidyl ether of ethylene glycol monophenyl ether; Glycidyl ether of glycol monophenyl ether, glycidyl ether of propylene glycol monophenyl ether, glycidyl ether of polypropylene glycol monophenyl ether, glycidyl ether of propylene glycol mono (pt-butyl) phenyl ether, and ethylene glycol monononyl phenyl ether Glycidyl ether and the like. Examples of the α-olefin oxide include alpha olefin oxide-168 [product of Adeka Argas Chemical Co., Ltd., oxirane oxygen content: 5.9%], and alpha olefin oxide-124 [Adeka Gas Gas Co., Ltd. product, oxirane oxygen content] 7.7%] and the like.

The monoepoxy fatty acid ester is a compound obtained by epoxidizing an unsaturated group of an alcohol ester of an unsaturated fatty acid, and examples thereof include epoxidized butyl oleate and epoxidized octyl oleate.

These compounds having a non-polar group may be used alone or in combination of two or more.

From the viewpoint of improving the offset resistance of the electrophotographic toner, the above-mentioned (c) non-polar group-containing monoepoxy compound is further used as a raw material for the non-polar group-modified polyester resin (B). It is preferable to use a polyepoxy compound having at least two epoxy groups.

Examples of the polyepoxy compound having two or more epoxy groups include bisphenol A type epoxy resin, novolak type epoxy resin, ethylene glycol diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, and pentane. Erythritol tetraglycidyl ether, hydroquinone diglycidyl ether, semi-dry or dry fatty acid ester epoxy compounds, and the like.

The content of the compound (c) is not particularly limited, but is preferably 0.1 to 50% by weight in the polyester resin (A) in consideration of easiness of production and the like.
40% by weight is more preferred.

Examples of the urethane-modified polyester resin (C) used in the present invention include a reaction product of the polyester resin (A) or (B) with (d) a polyisocyanate compound and / or a blocked polyisocyanate compound. No. Various aromatic diisocyanates, such as tolylene diisocyanate or diphenylmethane-4,4'-diisocyanate, are typical examples of the polyisocyanate compound described above;

Meta-xylylene diisocyanate, α,
various aralkyl diisocyanates, such as α, α ′, α′-tetramethyl-meta-xylylene diisocyanate;

Such as hexamethylene diisocyanate, lysine diisocyanate, 1,3-bisisocyanatomethylcyclohexane, 2-methyl-1,3-diisocyanatocyclohexane, 2-methyl-1,5-diisocyanatocyclohexane or isophorone diisocyanate , Various aliphatic or alicyclic diisocyanates;

The polyisocyanates described above can be obtained by addition reaction with polyhydric alcohols.
Prepolymers having isocyanate groups;

Prepolymers having an isocyanurate ring obtained by cyclizing and trimerizing various polyisocyanates as described above;

Polyisocyanates having a biuret structure obtained by reacting various polyisocyanates as described above with water;

Further, a vinyl monomer having various isocyanate groups such as 2-isocyanatoethyl (meth) acrylate, 3-isopropenyl-α, α-dimethylbenzyl isocyanate or (meth) acryloyl isocyanate may be used alone. Coalescence

Alternatively, these isocyanate group-containing vinyl monomers can be copolymerized with the monomers.
(Meth) acrylic, vinyl ester, vinyl ether, aromatic vinyl or fluoroolefin-based vinyl monomers obtained by copolymerization, respectively, isocyanate group-containing acrylic copolymer and vinyl ester Various vinyl copolymers such as a copolymer or a fluoroolefin copolymer.

Particularly representative examples of the above-mentioned blocked polyisocyanate compounds include various types of polyisocyanate compounds obtained by blocking various polyisocyanate compounds as described above with various blocking agents as described below. And compounds in which isocyanate groups are regenerated by heat, such as block polyisocyanate compounds of the formula (I) and compounds containing various uretdione structures obtained by cyclizing and dimerizing isocyanate groups.

Particularly typical examples of the blocking agent used in preparing the blocked polyisocyanate compound include methanol, ethanol,
Various carbinol group-containing compounds, such as benzyl alcohol or lactate;

Various phenolic hydroxyl group-containing compounds such as phenol, salicylate or cresol; or various amides such as ε-caprolactam, 2-pyrrolidone or acetanilide;

Alternatively, various oximes such as acetone oxime or methyl ethyl ketoxime, and various active methylene compounds such as methyl acetoacetate, ethyl acetoacetate or acetylacetone may be used.

The urea-modified polyester resin (D) used in the present invention includes a reaction product of a polyester prepolymer (E) having an isocyanate group with an amine (e). Examples of the polyester prepolymer (E) having an isocyanate group include a product obtained by further reacting the polyester resin (A) or (B) having a hydroxyl group with the (d) polyisocyanate compound and / or the blocked polyisocyanate compound. Is mentioned.

The amines as component (e) include diamines (e1), triamine or higher polyamines (e2), amino alcohols (e3), aminomercaptans (e4), amino acids (e5), and amino acids e1 to e5. Those obtained by blocking a group (e6) and the like can be mentioned. Diamine (e1)
As aliphatic diamines such as ethylenediamine, tetramethylenediamine, and hexamethylenediamine;

Aromatic diamines such as phenylenediamine, diethyltoluenediamine and 4,4'diaminodiphenylmethane;

Alicyclic diamines such as 4,4'-diamino-3,3'dimethyldicyclohexylmethane, diaminecyclohexane, and isophoronediamine;

The trivalent or higher polyamine (e2) includes
Examples include diethylenetriamine and triethylenetetramine.

Examples of the amino alcohol (e3) include ethanolamine and hydroxyethylaniline.

Examples of the aminomercaptan (e4) include aminoethylmercaptan, aminopropylmercaptan and the like.

Examples of the amino acid (e5) include aminopropionic acid and aminocaproic acid.

Examples of the compounds obtained by blocking the amino groups e1 to e5 (e6) include ketimine compounds and oxazoline compounds obtained from the above amines e1 to e5 and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.). Can be

If necessary, the molecular weight of the urea-modified polyester resin (D) can be adjusted using an elongation terminator. Examples of the elongation terminator include monoamines (diethylamine, dibutylamine, butylamine, laurylamine, etc.), and those obtained by blocking them (ketimine compounds).

The polyester resin (A) and the non-polar group-modified polyester resin (B) used in the present invention can be prepared by a known and commonly used method.

That is, a method of preparing a polyester resin by polymerizing the above-mentioned raw material components, ie, the polybasic acid compounds, the polyhydric alcohols and the compound having a non-polar group, under heating in a nitrogen atmosphere is used. be able to. As the apparatus used in the polymerization, a batch-type production apparatus such as a reaction vessel equipped with a nitrogen inlet, a thermometer, a stirrer, a rectification tower, and the like can be suitably used, and an extrusion equipped with a deaeration port can be used. An apparatus, a continuous reaction apparatus, a kneader, and the like can also be used. Further, the esterification reaction can be promoted by appropriately reducing the pressure of the reaction system as required. Further, in order to accelerate the esterification reaction, a known and commonly used catalyst can be added.

In order to prepare the urethane-modified polyester resin (C) and the urea-modified polyester resin (D) used in the present invention, for example, a one-shot method, a prepolymer method or the like can be used as a known and commonly used method.

Next, the properties of the condensation resin (hereinafter referred to as polyester resin) used in the present invention will be described.

The weight-average molecular weight of the polyester resin used in the present invention is from 2,000 to 1,000 in consideration of easiness of production and fixing properties as a binder for toner.
Preferably it is 000. In this range, it is more preferable that the color toner is 5,000 to 300,000.

The hydroxyl value of the polyester resin used in the present invention is from 5 to 100 mgKOH /, considering the charging characteristics as a toner binder and the ease of forming spherical particles.
g, more preferably 7 to 70 mgKOH / g. From the same viewpoint, the polyester resin used in the present invention has an acid value of 5 to 100 m.
gKOH / g, more preferably 7-70 mgKOH / g
Is desirably within the range.

The polyester resin used in the present invention preferably has a glass transition temperature of 50 to 80 ° C. measured by a differential scanning calorimeter (DSC) in consideration of the thermal stability of the toner, and more preferably. 55-75 ° C
It is. Further, from the same viewpoint, the softening temperature of the polyester resin is preferably in the range of 70 to 180 ° C, more preferably in the range of 80 to 160 ° C.

Examples of the wax used in the present invention include various known waxes for improving low-temperature fixability and offset resistance. Examples thereof include polypropylene wax, polyethylene wax, polyamide wax, Fischer-Tropsch wax, synthetic ester wax, and various natural waxes. Among them, carnauba wax, montan ester wax, rice wax and / or Alternatively, it is preferable to use a scale insect wax.

The toner for electrophotography according to the present invention is characterized in that the wax having a low softening point is included in the toner particles and is localized near the surface of the particles.
The state where the wax is localized on the surface of the toner particles is as follows.
For example, it is shown in FIGS. 1, 2 and 3. On the other hand, when wax is mixed with the conventional toner particles, the result is as shown in FIG. 4, where the wax adheres to the outer surface of the toner particles. Therefore, the toner for electrophotography according to the present invention has an effect of being excellent in heat stability and enabling stable continuous printing, since the wax does not exist on the outer surface of the particles unlike the conventional toner.

The electrophotographic toner according to the present invention contains the above-mentioned polyester resin and wax as essential components, and may contain other components as exemplified below, if necessary.

Other components include a colorant, a magnetic material, a charge control agent, a flow control agent and the like.

Examples of the colorant include all pigments. As the pigment, for example, Hansa Yellow 10
G, Hansa Yellow G, Benzidine Yellow G, Benzidine Yellow GR, Permanent Orange, Resor Fast Orange 3GR, Permanent Orange GT
R, Vulcan Fast Orange GG, Permanent Red 4R, Fire Red, p-Chloro-o-nitroaniline Red, Brilliant Fast Scarlet, Brilliant Carmine BS, Pyrazolone Red, Risor Red, Lake Red C, Lake Red D, Brilliant Scarlet G, Permanent Red F5R, Brilliant Carmine 6B, Pigment Scarlet 3B, Rhodamine Lake (Fanal Color), Alizarin Lake, Toluidine Maroon, Permanent Bordeaux F2
R, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Media, Thioindigo Maroon, Perylene Red, Permanent Red BL, Permanent Pink E (FH) which is a quinacridone pigment, Phthalocyanine Blue, First Sky Blue, Indance Renblue RS, Pigment Green B, Naphthol Green B, Green Gold, Phthalocyanine Green, Naphthol Yellow S Lake, Quinoline Yellow Lake, Persian Orange, Peacock Blue Lake, Acid Green Lake, Para Red, Bordeaux 5
B, and pigments such as alkali blue toner aniline black and carbon black.

Examples of the magnetic material include triiron tetroxide, gamma iron oxide, various ferrite powders, and iron powders.

The charge controlling agent may be a low molecular weight compound or a high molecular weight compound as long as it can control the charging characteristics. Typical examples thereof include a nigrosine dye and a quaternary. Ammonium compounds, homopolymers or copolymers of amino group compounds,
There are organometallic complexes, chelate compounds and the like.

The flow regulator is added in order to improve the flowability of the toner. Use is made of fine powder of vinylidene fluoride, fine powder of polytetrafluoroethylene, fine powder of silica by a wet method or a dry method, or the like. Can be.

When the electrophotographic toner of the present invention has a spherical shape, the spherical shape exerts an effect that carrier contamination is less likely to occur as compared with the pulverization method, that the durability is extremely high, and that the fluidity is good. The spherical shape includes a true spherical shape, an elliptical shape, and the like, but a true spherical shape is preferable from the viewpoint of improving durability.

The particle diameter of the electrophotographic toner of the present invention is usually from 3 to 20 μm in terms of volume average particle diameter, but is preferably from 4 to 8 μm from the viewpoint of image resolution.

The average particle size of the toner in the present invention is as follows.
It refers to a value of 50% volume average particle diameter measured by Coulter Multisizer 2 (manufactured by Beckman Coulter, Inc.) which is a particle size distribution measuring device.

The method for producing an electrophotographic toner in which the polyester resin of the present invention contains the above-mentioned other components is not particularly limited, but can be suitably prepared, for example, by the following method.

That is, (1) First, a polyester kneader, a wax, a pigment, and other necessary additives, for example, a charge control agent, are charged in the same manner as in the case of the production of a pulverized toner. The mixture is melt-kneaded using an extruder and the like to produce a colored resin melt. (2) Next, this colored resin melt and an aqueous solution containing a substance that neutralizes the polar group of the polyester resin, and heated to a temperature equal to or higher than the softening point of the synthetic resin by heating and further applying pressure as necessary. And (3) finely dispersing the colored resin melt in an aqueous medium by mechanical means while maintaining the temperature of the mixture in a molten state of the synthetic resin;
(4) Immediately thereafter, an aqueous dispersion of colored resin fine particles is produced by rapid cooling, (5) the colored resin fine particles are separated from the dispersion, and (6) the separated colored resin fine particles are dried. As in the case of the conventional pulverization method toner, the colored resin fine particles are classified, and an external additive such as hydrophobic silica is added to obtain a toner.

Examples of the neutralizing agent for the polar group of the polyester resin include alkali compounds such as sodium hydroxide, potassium hydroxide and lithium hydroxide, carbonates and acetates thereof, and aqueous ammonia, methylamine and dimethyl. Amines, trimethylamine, ethylamine, diethylamine, alkylamines such as triethylamine,
Alkanolamines such as diethanolamine can be used. Among them, it is preferable to use aqueous ammonia since most of them are removed in the above-mentioned drying step and the characteristics of the toner are not affected.

Examples of the apparatus for finely dispersing by the above-mentioned mechanical means include a Menton-Gaulin high-pressure homogenizer (Golin), a continuous ultrasonic homogenizer (Nippon Seiki Co., Ltd.), a nanomizer (Nanomizer), and a microfluidizer ( Mizuho Industry Co., Ltd.), Harel homogenizer, slasher (Mitsui Mining Co., Ltd.), Cavitron (Eurotech Co., Ltd.) and the like.

A developer can be prepared by mixing and mixing a carrier with the electrophotographic toner obtained above.

[0083]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited to these examples. All parts and percentages in the examples are on a weight basis.

Example 1 A bisphenol A ethylene oxide adduct 63 was added to a reactor having a stirrer, a temperature controller, and an N ₂ gas introducing pipe.
9.9 parts, terephthalic acid 350.1 parts, Kajura E1
0 (40.0 parts of monoglycidyl ester of a branched fatty acid manufactured by Shell Chemical Co., Ltd.) and 0.3 part of dibutyltin oxide were added and stirred at 240 ° C. under a nitrogen stream. The reaction is JIS
The reaction was followed by a softening point test method (ring and ball method) in accordance with K-2207. When the softening point reached 110 ° C., the reaction was terminated, and a polyester resin (R-1) was obtained. The obtained polyester resin (R-1) is a light yellow solid and has an acid value of 1
2.3 mgKOH / g, glass transition temperature of 63.5 ° C. by DSC measurement, and polystyrene-equivalent weight average molecular weight of 12,000 by GPC (gel permeation chromatography).

94 parts of the above polyester resin (R-1) and wax (carnauba wax; manufactured by Nippon Wax Co., Ltd.)
1 part and 5 parts of carbon black (Elftex; manufactured by Cabot Corp.) were used as a colored resin kneaded material using a twin-screw continuous kneader, which was heated to 180 ° C. to obtain a colored resin melt, and 100 g of Cavitron CD1010 per minute was added. Transferred at speed.

A separately prepared aqueous medium tank was charged with 0.37% by weight diluted ammonia water obtained by diluting reagent ammonia water with ion-exchanged water, and heated to 120 ° C. with a heat exchanger at a rate of 0.2 liter per minute. At the same time as the above colored resin melt and transferred to the Cavitron. The rotation speed of the rotor is 7500 rpm, the pressure is 5 kg / cm2,
The produced slurry was cooled from 125 ° C. to 25 ° C. within 10 seconds and taken out. The toner particles were spherical. The average particle size of the toner particles was 6.2 microns as measured by Coulter Multisizer 2. The toner base particles were separated by filtration, washed with water, and dried to obtain a powdered toner base body.

The toner base particles were dry-blended with 0.2% hydrophobic silica (R-972 manufactured by Nippon Aerosil Co., Ltd.) to obtain a spherical black toner having an average particle diameter of 6.2 μm.

Application Example 1 After storing the toner obtained in Example 1 at 50 ° C. for 8 hours,
The residual ratio on the sieve wire net was measured with a 2-mesh sieve for 3 minutes. The higher the heat stability of the toner, the lower the residual ratio. As a result of the measurement, the residual ratio was 4%. 5 parts of the toner obtained in Example 1 and 95 parts of a ferrite carrier having an average particle diameter of 80 microns (electric resistance is 107 ohm-cm) were mixed in a 1-liter polybin at a rotation speed of 100 rpm for 1 hour to prepare a developer. did. When the charge amount was measured with a blow-off powder charge amount measurement device TB-200, it was -30 μm.
C / g. The developer was charged into a developing box of a commercial copying machine, and was driven by an external motor to perform a 200-hour forced stirring test (a durability simulation test in which development was not performed). After 200 hours, the charge amount was measured to be −30 μC / g. The carrier had a resistivity of 107 ohm-cm after the toner was separated by blow-off. When the average particle size of the separated toner was measured, it was 6.2 μm. Since this toner is spherical, it has been found that the toner is extremely durable and hardly causes carrier contamination.

Next, the quietness density was measured using a powder tester manufactured by Hosokawa Micron.

The quietness density is greater for toners having better fluidity. The quietness density of this toner was 0.38.

An unfixed image was picked up with a commercially available copying machine using a selenium photosensitive drum using the developer described above, and then a modified commercial printer (manufactured by Canon: LASER SHOT 406) was used.
Using the fixing device B), the surface temperature of the fixing roller is changed stepwise to capture a fixed image, and the occurrence of offset development at each surface temperature is determined by performing a peeling test using a cellophane tape on the fixed image. When the non-offset temperature region was evaluated, the fixing start temperature of this toner was 90 ° C., and an offset occurred at 145 ° C.

Comparative Example 1 94 parts of the polyester resin (R-1) synthesized in Example 1 and a wax (carnauba wax; Nippon Wax Co., Ltd.)
1 part) and 5 parts of carbon black (Elftex; manufactured by Cabot) into a colored resin kneaded product using a twin-screw continuous kneader, pulverized using a jet mill, and then classified to obtain a toner base material. I got 0.2% of hydrophobic silica (R-Nippon Aerosil Co., Ltd.)
972) was dry blended to obtain a black toner having an average particle size of 6.8 μm.

Comparative Application Example 1 After storing the toner obtained in Comparative Example 1 at 50 ° C. for 8 hours,
The mixture was sieved with a 2-mesh sieve for 3 minutes, and the residual ratio on the wire mesh was measured. As a result of the measurement, the residual ratio was 22%, and it was found that the toner was extremely poor in heat stability. 5 parts of the toner obtained in Comparative Example 1 and a ferrite carrier having an average particle size of 80 μm (electric resistance is 107 ohm cm) 9
5 parts were mixed in a 1 liter polybin at a rotation speed of 100 rpm for 1 hour to prepare a developer. When the charge amount was measured by a blow-off powder charge amount measurement device TB-200,
-32 [mu] C / g. The developer was charged into a developing box of a commercial copying machine, and was driven by an external motor to perform a 200-hour forced stirring test (a durability simulation test in which development was not performed). After 200 hours, when the charge amount was measured, it was changed to -45 C / g. When the electrical resistance of the carrier after separating the toner by blow-off was measured, it was found to be 109 ohm-cm. When the average particle diameter of the separated toner was measured, it was found to be 5.5 microns. This toner was found to be indefinite in shape and inferior in durability, excessively pulverized, and liable to cause carrier contamination.

Next, the quietness density was measured using a powder tester manufactured by Hosokawa Micron. The quietness density of this toner was 0.27. Since this toner has an irregular shape, it can be seen that the powder fluidity is inferior to the spherical toner.

An unfixed image was picked up with a commercially available copying machine using a selenium photosensitive drum using the developer described above, and then a modified commercial printer (manufactured by Canon: LASER SHOT 406) was used.
Using the fixing device B), the surface temperature of the fixing roller is changed stepwise to capture a fixed image, and the occurrence of offset development at each surface temperature is determined by performing a peeling test using a cellophane tape on the fixed image. When the non-offset temperature region was evaluated, the fixing start temperature of this toner was 100 ° C., and an offset occurred at 130 ° C.

[0096]

The toner for electrophotography according to the present invention is excellent in heat stability, low-temperature fixability and hot offset resistance, and has excellent powder fluidity and durability as compared with the toner according to the prior art. is there.

[Brief description of the drawings]

FIG. 1 shows a schematic view of the structure of the toner particles of the present invention.

FIG. 2 shows a schematic view of the structure of the toner particles of the present invention.

FIG. 3 shows a schematic view of the structure of the toner particles of the present invention.

FIG. 4 is a schematic view showing the structure of toner particles obtained by a conventional pulverization method.

[Explanation of symbols]

 1: toner particles 2: wax

Claims (7)

[Claims] 1. An electrophotographic toner containing at least a resin and a wax, wherein the resin is a condensation resin, and the wax is included in the toner particles and is localized near the surface of the particles. Electrophotographic toner. 2. The electrophotographic toner according to claim 1, wherein the condensation resin is a polyester resin. 3. The electrophotographic toner according to claim 2, wherein the polyester resin is a polyester resin having a non-polar group in a molecule. 4. The polyester resin has an acid value of 5 to 100 m.
The electrophotographic toner according to any one of claims 1 to 3, which is gKOH / g. 5. The electrophotographic toner according to claim 1, wherein the toner is spherical. 6. A method for electrophotography, comprising: dispersing a colored resin melt comprising a wax, a condensation resin and a pigment in high-temperature water while maintaining the molten state of the resin, cooling and then drying. Manufacturing method of toner. 7. The method according to claim 6, wherein the condensation resin is a polyester resin.