JP2003107798A - Electrophotographic toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide electrophotographic toners which are good in fixing stability and are excellent in offset resistance. SOLUTION: The electrophotographic toners contain a binder resin containing a polyester resin (A) of <=0.3 wt.% in gel component, 3,000 to 20,000 in the weight average molecular weight (Mw) measured by a GPC method, 1,000 to 5,000 in number average molecular weight (Mn), 2 to 10 in their ratio (Mw/Mn) and 80 to 140 deg.C in a 1/2 falling temperature in a flow tester and polyester resin (B) of <=2 wt.% in gel component, 200,000 to 2,000,000 in the weight average molecular weight (Mw) measured by a GPC method, 5,000 to 20,000 in number average molecular weight (Mn), 10 to 400 in their ratio (Mw/Mn) and 150 to 250 deg.C in a 1/2 falling temperature in a flow tester and a coloring agent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic toner having good low-temperature fixability and excellent offset resistance.

[0002]

2. Description of the Related Art Conventionally, polyester resins, polyethylene resins, epoxy resins and the like have been proposed as toner resins. Among them, polyester resins, which have a good fixing property even if the amount of heat used for fixing is small, have been attracting attention for increasing the printing processing speed. However, in the polyester resin, a part of the toner forming the image is transferred to the surface of the heat roller at the time of fixing, and the toner is retransferred to a transfer paper or the like sent next, and an offset phenomenon that stains the image is likely to occur. It has drawbacks. If the softening point and crosslink density of the polyester resin are increased to improve the offset resistance, the low temperature fixability deteriorates.

A composite crosslinked polyester obtained by reacting an epoxy compound having a valency of 2 or more with an unsaturated dibasic acid as a raw material, as a resin for an electrophotographic toner having improved low-temperature fixing property and anti-offset property. An electrophotographic toner made of a resin is described in JP-A-2000-181137. This electrophotographic toner improves the low-temperature fixability of the toner by increasing the gel content of the polyester resin as a toner raw material to a high concentration of 10% or more, and at the upper limit of the temperature region (non-offset region) where the offset phenomenon does not occur. Although an attempt has been made to raise the temperature, the upper limit temperature of the non-offset region is lowered due to the decrease of the viscosity of the polyester resin in the kneading step during toner production, and there is a limit to obtaining a toner having a high upper limit temperature of the non-offset region. Further, since the raw material polyester resin has a high gel content, special equipment is required at the time of production, and it is difficult to handle after production.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electrophotographic toner which has good low-temperature fixability and excellent offset resistance.

[0005]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that the gel content is 2% by weight or less, and the weight average molecular weight (Mw) measured by GPC (gel permeation chromatography) is 200,000 to 2,000,000, number average molecular weight (Mn) is 5,000 to 20,000, ratio (Mw / Mn) of these is 10 to 400, and 1/2 drop temperature (T1 / 2) in flow tester is 150. The polyester resin (B) having a temperature of up to 250 ° C. does not reduce the viscosity of the polyester resin in the kneading step during toner production, and a toner having a high upper limit temperature in the non-offset region can be obtained. , Gel content is less than 0.3% by weight,
Weight average molecular weight (Mw) measured by GPC method is 3,000
0-20,000, number average molecular weight (Mn) is 1,000-
5,000, the ratio (Mw / Mn) of these is 2 to 10 and the 1/2 drop temperature (T1 / 2) in the flow tester is 80 to
By using a binder resin containing a polyester resin (A) having a temperature of 140 ° C., it was found that a toner having a high upper limit temperature in the non-offset region and a good low-temperature fixability can be obtained, and the present invention is completed. It was

That is, the present invention has a gel content of 0.3% by weight or less and GPC (gel permeation chromatography).
Weight average molecular weight (Mw) measured by the method is 3,000 to 2
000, number average molecular weight (Mn) is 1,000 to 5.0
00, these ratios (Mw / Mn) are 2 to 10 and the 1/2 drop temperature (T1 / 2) in the flow tester is 80 to 140.
Polyester resin (A) which is ℃ and gel content 2% by weight
Hereinafter, the weight average molecular weight (Mw) measured by the GPC method is 2
, 000,000 to 2,000,000, number average molecular weight (M
n) is 5,000 to 20,000, and these ratios (Mw / M
n) is 10 to 400 and a binder resin containing a polyester resin (B) having a 1/2 drop temperature (T1 / 2) in a flow tester of 150 to 250 ° C., and a colorant. The present invention also provides an electrophotographic toner.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The polyester resin (A) has a gel content of 0.3% by weight or less, a weight average molecular weight (Mw) measured by a GPC method of 3,000 to 20,000, and a number average molecular weight (Mn). Is 1,000 to 5,000, and the ratio (Mw /
If the Mn) is 2 to 10 and the 1/2 drop temperature (T1 / 2) in the flow tester is 80 to 140 ° C, it can be used without limitation regardless of the production method and the raw material.

The gel content of the polyester resin (A) is preferably as small as possible, but if it is 0.3% by weight or less, the polyester resin (A) used in the present invention can be used without any problem. When the gel content exceeds 0.3% by weight, the strength of the resin becomes insufficient and the storage stability of the toner deteriorates.

The weight average molecular weight (Mw) of the polyester resin (A) measured by the GPC method is 3,000 or more and 20,0.
It must be 00 or less. Below 3000,
The strength of the resin is not sufficient, the storage stability of the toner becomes poor, and when it exceeds 20,000, the viscosity becomes high and the fixing at low temperature becomes poor, which is not preferable. Above all, 4,000
The range of 0 to 10,000 is more preferable.

The number average molecular weight (Mn) of the polyester resin (A) measured by the GPC method must be 1,000 or more and 5,000 or less. If it is less than 1000, the strength of the resin is insufficient and the storage stability of the toner is deteriorated.
If it exceeds 000, the viscosity becomes high and the fixing at low temperature becomes poor, which is not preferable. Above all, 2,000 to 4,000
Is more preferable.

The Mw / Mn of the polyester resin (A) is 2
It is necessary to be 10 but a value close to 2 is more preferable. When it exceeds 10, the viscosity becomes high and the fixing at low temperature becomes poor. Particularly, a more preferable range of Mw / Mn is 2 to 5.

It is necessary that the 1/2 drop temperature (T1 / 2) of the polyester resin (A) in the flow tester is 80 to 140 ° C. If the temperature is lower than 80 ° C., the strength of the resin is insufficient and the storage stability of the toner is deteriorated. If the temperature is higher than 140 ° C., the viscosity is high and the fixing at low temperature is deteriorated. T1 / 2
Is more preferably 80 to 120 ° C.

The polyester resin (B) has a gel content of 2% by weight or less, a weight average molecular weight (Mw) measured by GPC of 200,000 to 2,000,000, and a number average molecular weight (M).
n) is 5,000 to 20,000, and these ratios (Mw / M
If n) is 10 to 400 and the 1/2 drop temperature (T1 / 2) in the flow tester is 150 to 250 ° C., the production method,
It can be used without restriction regardless of the raw material.

The gel content of the polyester resin (B) must be 2% by weight or less. If the gel content exceeds 2% by weight, the branching or cross-linking portion of the polyester is cut during the kneading process during the toner production, and the viscosity of the resin decreases, resulting in poor balance between low-temperature fixability and offset resistance. Further, the gel content is preferably 0.2% by weight or more from the viewpoint that the fixing temperature range of the toner can be wide. Since the gel content has a good balance between low-temperature fixability and anti-offset property, and has a wide fixing temperature range of the toner, it is 0.
It is preferably from 2 to 0.7%.

The weight average molecular weight (Mw) of the polyester resin (B) measured by GPC method is 200,000 or more, 2.
It should be less than or equal to, 000,000. 200,0
When it is less than 00, the fixing property of the toner at high temperature is deteriorated,
If it exceeds 2,000,000, the viscosity of the resin decreases during the kneading process during toner production, and the maximum temperature in the non-offset region decreases, which is not preferable. Above all, from 200,000
The range of 1,000,000 is more preferable.

The number average molecular weight (Mn) of the polyester resin (B) measured by the GPC method is 5,000 or more and 20,000 or more.
It must be 0 or less. Below 5,000,
The fixing property of the toner at high temperature deteriorates, and when it exceeds 20000, the viscosity of the resin decreases in the kneading process during the toner production,
This is not preferable because the upper limit temperature of the non-offset region decreases. Especially, the range of 5,000 to 10,000 is more preferable.

The Mw / Mn of the polyester resin (B) is
It is necessary to be 10 or more and 400 or less. When it is less than 10, the fixing property of the toner at high temperature is deteriorated, and when it exceeds 400, the viscosity of the resin is lowered during the kneading process during the production of the toner,
This is not preferable because the upper limit temperature of the non-offset region decreases. Particularly, a more preferable range of Mw / Mn is 2
It is 0 to 200.

The drop temperature (T1 / 2) of the polyester resin (B) in the flow tester is 150 ° C. or higher and 250 ° C.
It must be: If it is lower than 150 ° C., the fixability of the toner at high temperature becomes poor, and if it exceeds 250 ° C., the viscosity of the resin decreases in the kneading process during toner production, and the upper limit temperature in the non-offset region lowers, which is not preferable. T1 /
2 is more preferably 160 to 230 ° C.

Next, a method for preparing the polyester resin (A) and the polyester resin (B) will be described. Various methods can be used for the preparation of the polyester resin (A) and the polyester resin (B), for example, a transesterification reaction method using a lower alkyl ester such as dicarboxylic acid methyl ester, a normal pressure dehydration reaction method, a reduced pressure dehydration reaction. Method, solution polycondensation method, solid phase polycondensation reaction method and the like. As the apparatus used at this time, a batch-type production apparatus such as a reaction vessel equipped with a nitrogen inlet, a thermometer, a stirrer, and a rectification column can be preferably used, and an extruder equipped with a degassing port A continuous reaction device, a kneader, or the like can also be used. Furthermore, in order to accelerate the esterification reaction or transesterification reaction, dibutyltin oxide, tetrabutyl titanate,
Various catalysts such as an esterification catalyst such as paratoluene sulfonic acid and a transesterification catalyst such as a lead compound, a tin compound and tetrapropyl titanate may be added.

The polyester resin (A) can be prepared, for example, by using dicarboxylic acid and diol as essential components, and using monobasic acid, monohydric alcohol and the like in combination within a range that does not impair the effects of the present invention.

The method for preparing the polyester resin (A) is, for example, dicarboxylic acid and diol as essential components, and if necessary, a monobasic acid, a monovalent alcohol and a catalyst are mixed and heated in a flask, and a nitrogen stream is supplied. Gradually 210-250 ℃
A method of performing an esterification reaction by reacting for 8 to 12 hours with stirring in the range of 1) and the like can be mentioned. The progress of the esterification reaction of the polyester resin can be confirmed by measuring the acid value or viscosity of the polyester resin. For example, the reaction end point is the polyester resin having a softening point of about 80 to 120 ° C. according to the ring and ball method. Resin (A) is obtained. The dicarboxylic acid and the diol may be mixed in a ratio such that the hydroxyl group of the diol is 0.95 to 1.05 mol with respect to 1 mol of the carboxyl group of the dicarboxylic acid.

The polyester resin (B) comprises a dicarboxylic acid and a diol as essential components, and a polyester resin obtained by using trifunctional or higher functional polybasic acids, polyhydric alcohols and epoxy compounds as a part of raw materials. Is mentioned. Trifunctional or higher polybasic acids, trifunctional or higher polyhydric alcohols and epoxy compounds are added in the range of 0.5 to 3.0% by weight based on the total amount of the raw material components. Further, a monobasic acid, a monovalent higher alcohol or the like can be used together within a range not impairing the effects of the present invention.

Among the above-mentioned polyester resins (B), a polyester resin obtained by reacting a dicarboxylic acid, a diol and a bifunctional epoxy compound is preferable in order to widen the fixing temperature range of the toner, and above all, 2 It is more preferable that the polyester resin is obtained by using raw material components having a functional epoxy compound content of 0.5 to 2.5% by weight.

Further, the polyester resin (B) is a raw material component containing 1 to 10% by weight of a monoepoxy compound having an alkyl group having 4 to 28 carbon atoms in addition to a dicarboxylic acid, a diol and a bifunctional epoxy compound. The polyester resin obtained by using is especially preferable.

The polyester resin (B) is a polyester resin obtained by reacting a dicarboxylic acid as a raw material component with a diol containing 90 mol% or more of an aliphatic diol and / or an alicyclic diol component. Preferably there is.

The polyester resin (B) can be prepared by mixing, for example, a dicarboxylic acid, a diol, trifunctional or higher polybasic acids, trifunctional or higher polyhydric alcohols, an epoxy compound and, if necessary, a catalyst in a flask. Examples of the method include a method of heating and stirring under a nitrogen stream in the range of 210 to 250 ° C. under normal pressure for 15 to 20 hours to carry out an esterification reaction. The progress of the esterification reaction can be confirmed by measuring the acid value or viscosity of the polyester resin. For example, when the softening point of the polyester resin by the ring and ball method is about 120 to 190 ° C., the reaction end point is set, and the polyester resin (B) Is obtained. Dicarboxylic acids and diols are carboxyl groups of dicarboxylic acids 1
The hydroxyl group of the diol is 0.95 to mol
It is advisable to mix them at a ratio of 1.05 mol.

Next, the raw materials used for preparing the polyester resin (A) and the polyester resin (B) will be described.
Examples of the dicarboxylic acid include maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, oxalic acid, malonic acid, succinic acid, succinic anhydride, dodecyl succinic acid, dodecyl succinic anhydride, dodecenyl succinic acid, Aliphatic dibasic acids such as dodecenyl succinic anhydride, adipic acid, azelaic acid, sebacic acid, decane-1,10-dicarboxylic acid; phthalic acid, tetrahydrophthalic acid and its anhydride, tetrabromophthalic acid and its anhydride, Tetrachlorophthalic acid and its anhydride, het acid and its anhydride, hymic acid and its anhydride, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, 2,
Aromatic or alicyclic dibasic acids such as 6-naphthalenedicarboxylic acid;

Further, as the trifunctional or higher functional polybasic acids, carboxylic acids having three or more carboxyl groups in one molecule and reactive derivatives thereof can also be used. Typical examples thereof include trimellitic acid, trimellitic anhydride, methylcyclohexene tricarboxylic acid, methylcyclohexene tricarboxylic acid anhydride, pyromellitic acid and pyromellitic dianhydride.

Further, as the above-mentioned polybasic acids such as dicarboxylic acids and trifunctional or higher functional carboxylic acids, those in which a part or all of the carboxyl groups thereof are alkyl esters, alkenyl esters or aryl esters can also be used.

As a raw material component, for example, dimethylol-
A compound having both a hydroxyl group and a carboxyl group in one molecule, such as lepropionic acid, dimethylolbutanoic acid, and 6-hydroxyhexanoic acid, or a reactive derivative thereof can also be used.

Further, as the monobasic acid, benzoic acid, p-
Examples thereof include tert-butylbenzoic acid.

The above basic acids may be used alone or in combination of two or more.

Next, as the diol, for example, ethylene glycol, 1,2-propylene glycol, 1,3-
Propanediol, 1,3-butylene glycol, 1,4-
Butylene glycol, 1,4-butanediol, 1,5
-Aliphatic diols such as pentanediol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol and neopentyl glycol; ethylene oxide of bisphenol A Adducts, bisphenol A alkylene oxide adducts such as propylene oxide adducts of bisphenol A; xylylene diglycol, 1,4-cyclohexane dimethanol, hydrogenated bisphenol A, hydrogenated bisphenol A Aralkylene glycol or alicyclic diols such as;
Etc.

As the trifunctional or higher polyhydric alcohols, compounds having three or more hydroxyl groups can also be used. For example, glycerin, trimethylolethane, trimethylolpropane, sorbitol, 1, 2, 3,6
-Hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, 2-methylpropanetriol, tris (2-hydroxyethyl) isocyanurate, etc. Examples of the alcohol include stearyl alcohol and the like.

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

Examples of the epoxy compound include bifunctional epoxy compounds such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, ethylene glycol diglycidyl ether, hydroquinone diglycidyl ether and neopentyl glycol diglycidyl ether. Of these, bisphenol A type epoxy resin and bisphenol F type epoxy resin are preferable. These may be used alone or in combination.

Examples of the monoepoxy compound having an alkyl group having 4 to 28 carbon atoms include alkyl phenyl glycidyl ether, alkyl glycidyl ether,
Examples thereof include glycidyl ester of carboxylic acid, glycidyl ether of adduct of alkylphenol alkylene oxide, and monoepoxy fatty acid alkyl ester.

Examples of the alkyl phenyl glycidyl ether include cresyl glycidyl ether, butyl phenyl glycidyl ether, nonyl phenyl glycidyl ether and the like.

Examples of alkyl glycidyl ethers include butyl glycidyl ether and 2-ethylhexyl glycidyl ether.

Examples of the glycidyl ester of carboxylic acid include nonanoic acid glycidyl ester, decanoic acid glycidyl ester, neodecanoic acid glycidyl ester,
Dodecanoic acid glycidyl ester and the like can be mentioned.

Examples of glycidyl ethers of adducts of alkylphenol alkylene oxides include glycidyl ethers of adducts of alkylene oxides such as ethylene oxide and propylene oxide with lower alkylphenols such as butylphenol. Specifically, for example, glycidyl ether of ethylene glycol monophenyl ether, glycidyl ether of polyethylene glycol monophenyl ether, glycidyl ether of propylene glycol monophenyl ether,
Examples thereof include glycidyl ether of polypropylene glycol monophenyl ether, glycidyl ether of propylene glycol mono (pt-butyl) phenyl ether, and glycidyl ether of ethylene glycol monononylphenyl ether.

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

The above-described monoepoxy compound having an alkyl group having 4 to 28 carbon atoms is preferably neodecanoic acid glycidyl ester. Further, they may be used alone or in combination of two or more kinds.

Here, in the present invention, the gel content is an insoluble content when the polyester resin (A) or the polyester resin (B) used in the present invention is dissolved in tetrahydrofuran for 24 hours. In the measurement, 250 ml of tetrahydrofuran was placed in a 300 ml glass container, and 1.5 g of finely crushed polyester resin was placed in a 500 mesh wire mesh bag (3 x 5 cm) and dissolved for 24 hours. Ask for.

The weight average molecular weight (Mw) and the number average molecular weight (Mn) of the polyester resin in the present invention are values measured by the GPC method under the conditions shown below for the components soluble in tetrahydrofuran. GPC device: Tosoh Corp. HLC-8120 GPC COLUMN: Tosoh Corp. TSK-GEL G-5000HXL G-4000HXL G-3000HXL G-2000HXL Solvent: Tetrahydrofuran solvent concentration: 0.5 wt% Flow speed: 1. 0ML / MIN

1/2 in the flow tester according to the present invention
Falling temperature (T1 / 2) is a high temperature type flow tester CF
Using T-500 (Shimadzu), load 10 kg / cm2,
Nozzle diameter 1mm, nozzle length 1mm, preheating 70 ℃
Sample rate 1.5g for 5 minutes at 6 ℃ / min
When measured and recorded as, when the height of the S-shaped curve in the plunger drop-temperature curve (softening flow local line) of the flow tester is h, it means the temperature of h / 2.

The binder resin used in the present invention is not limited as long as it contains the polyester resin (A) and the polyester resin (B), but among them, the polyester resin (A)
And the polyester resin (B) are mixed in a weight ratio (A) / (B) in the range of 30/70 to 70/30, the fixing property at low temperature is good, and the upper limit temperature of the non-offset temperature is high. Is preferable because a toner having no deterioration is obtained.

Next, the colorant used in the present invention will be described. As the colorant that can be used in the present invention, various ones can be used, and examples thereof include carbon black, nigrosine dye (CINo.50415B), aniline blue (CINo.50405), and calcooil blue (CINo.azo).
ic Blue3), Chrome Yellow (CINo.14090), Ultramarine Blue (CINo.77103), DuPont Oil Red (CINo.26105), Quinoline Yellow (CINo.4700)
5), Methylene Blue Chloride (CINo.52015), Phthalocyanine Blue (CINo.74160), Malachite Green Oxalate (CINo.74160), Malachite Green Oxalate (CINo.42000), Lamp Black (C.
I. No. 77266), Rose Bengal (CI No. 45435) and the like.

The content of the colorant is preferably in the range of 1 to 20 parts by weight with respect to 100 parts by weight of the binder resin. These colorants may be used either individually or in combination of two or more.

The toner of the present invention can be obtained by an extremely general production method regardless of a specific production method. For example, after the binder resin and the colorant are melt-kneaded at a melting point (softening point) or higher of the resin. , A method of pulverizing and classifying, and the like.

Specifically, for example, the above-mentioned binder resin and colorant and, if necessary, magnetic material, frictional charge control agent, anti-offset agent, lubricating oil, etc. are two-roll, three-roll, pressure kneader, or two. Mix by a kneading means such as a shaft extruder. At this time, the colorant and the like may be uniformly dispersed in the binder resin, and the conditions of the melt kneading are not particularly limited, but are usually 80 to 180 ° C. and 30 seconds to 2 hours. The colorant may be subjected to a flushing treatment in advance so as to be uniformly dispersed in the resin, or a masterbatch melt-kneaded with the resin at a high concentration may be used.

Then, after cooling it, it is finely pulverized by a pulverizer such as a jet mill and classified by an air classifier or the like.

[0053]

EXAMPLES The present invention will be described in detail below with reference to synthesis examples, examples and comparative examples. In the examples, "part" and "%" are based on weight unless otherwise specified.

Synthesis Example 1 [Synthesis of Polyester Resin (A)] 192 g of ethylene glycol, 324 g of neopentyl glycol, 996 g of terephthalic acid, and 1.0 g of dibutyltin oxide were placed in a glass 2-liter four-neck flask and placed under a nitrogen stream. Then, the temperature was gradually raised, and the reaction was carried out at 240 ° C. for 8 hours to obtain a polyester resin (A1) which was solid at room temperature and had an acid value of 10. Glass transition temperature (Tg) of polyester resin (A1) by differential thermal measurement (DSC) method, softening point by ring and ball method, 1/2 drop temperature (T1) by flow tester
/ 2), gel content, Mw, Mn and Mw / Mn are shown in Table 2.

Synthetic Example 2 and Synthetic Example 3 (Same as above) Polyester resin (A2) and polyester resin (A3) were synthesized in the same manner as in Synthetic Example 1 except that the raw materials were used in the formulations shown in Table 1. The measurement results are shown in Table 2 as in the case of the polyester resin (A1).

Synthesis Example 4 [Synthesis of Polyester Resin (B)] Ethylene glycol 224 was placed in a glass four-necked flask.
g, neopentyl glycol 250 g, terephthalic acid 9
96 g, Epicron 830 (Dainippon Ink and Chemicals, bisphenol F type bifunctional epoxy resin) 17 g,
Cardura E10 (Shell Japan product, neodecanoic acid glycidyl ester) (30 g) and dibutyltin oxide (1.0 g) were added, and the temperature was gradually raised under a nitrogen stream to obtain 245.
The reaction was performed at 18 ° C. for 18 hours to obtain a polyester resin (B1) which was solid at room temperature and had an acid value of 9. Polyester resin (B
1) glass transition temperature (Tg) by differential calorimetry (DSC) method, softening point by ring and ball method, 1 by flow tester
/ 2 fall temperature (T1 / 2), gel content, Mw, Mn and Mw /
Mn is shown in Table 2.

Synthetic Example 5 and Synthetic Example 6 (Same as above) Polyester resin (B2) and polyester resin (B3) were synthesized in the same manner as in Synthetic Example 1 except that the raw materials were used in the formulations shown in Table 1. Similar to the polyester resin (B1), Table 2 shows the measurement results.

[0058]

[Table 1] The abbreviations in the table are as follows. TPA: terephthalic acid IPA: isophthalic acid EG: ethylene glycol NPG: neopentyl glycol PG: propylene glycol CHDM: cyclohexanedimethanol BPA-EO: ethylene oxide 2.2 mol adduct of bisphenol A 830: Dainippon Ink and Chemicals, Inc. ) Bisphenol F type epoxy resin Epicron 830 850: Dainippon Ink and Chemicals Incorporated bisphenol A type epoxy resin Epicuron 850 CE-10: Shell Japan Co., Ltd. neodecanoic acid glycidyl ester cardura E-10

[0059]

[Table 2]

Synthesis Example 7 [Synthesis of Comparative Control Polyester Resin (b)] In the preparation of the polyester resin (B1) of Synthesis Example 4,
Instead of using 17 parts of Epicron 830, Epicron 83
Comparative polyester resin (b1) was synthesized in the same manner except that 42 parts of 0 was used. Polyester resin (b
1) glass transition temperature (Tg) by differential calorimetry (DSC) method, softening point by ring and ball method, 1 by flow tester
/ 2 fall temperature (T1 / 2), gel content, Mw, Mn and Mw /
Table 3 shows Mn.

Synthesis Example 8 (same as above) In the preparation of the polyester resin (B2) of Synthesis Example 5,
Change to use of 25 parts of Epicron 850 Epicron N-
A comparative polyester resin (b2) was synthesized in the same manner except that 25 parts of 695 (Dainippon Ink and Chemicals, Inc., cresol novolac type multifunctional epoxy resin) was used. Similar to the polyester resin (b1), Table 3 shows the measurement results.

[0062]

[Table 3]

Example 1 45 parts of polyester resin (A1) and 45 parts of polyester resin (B1) were mixed to prepare a binder resin. To this binder resin, 5 parts of carbon black MA-11 (Mitsubishi Chemical Products), 1.5 parts of Bontron E-81 (charge control agent manufactured by Orient Chemical Co., Ltd.), and 3.5 parts of Viscole 550P (polypropylene wax manufactured by Sanyo Kasei) were added. Mixing with a super mixer, and silica HDK
After adding 1 part of 3050EP (Clariant Japan product), kneading with a Henschel mixer, cooling, crushing with a jet mill and classification, a toner having an average particle diameter of 12 μm was obtained. 7 parts of the obtained toner was mixed with 93 parts of iron powder carrier to prepare a developer. Table 4 shows the measurement results of the prepared binder resin and the 1/2 drop temperature (T1 / 2) in the toner flow tester together with the mixing ratio of the polyester resin (A) and the polyester resin (B).

Examples 2 and 3 and Comparative Examples 1 and 2 A binder resin, a toner and a developer were prepared in the same manner as in Example 1 except that the polyester resin was mixed in the proportions shown in Table 4, to obtain a binder resin. The 1/2 drop temperature (T1 / 2) of the toner in the flow tester was measured. The measurement results are shown in Table 4.

[0065]

[Table 4]

Test Examples 1 to 3 and Comparative Test Examples 1 and 2 Evaluation of fixing start temperature, non-offset fixing temperature range and environmental image stability of the developers prepared in Examples 1 to 3 and Comparative Examples 1 and 2. Was performed as follows.

Evaluation of fixing start temperature and non-offset fixing temperature range 280 m after taking an unfixed image with a commercially available electronic copying machine
Using a heat roller fixing device having a speed of m / sec, the surface temperature of the heat roller was changed stepwise, and the measurement of the fixing start temperature and the presence or absence of the offset phenomenon were confirmed.

Evaluation of environmental image resistance stability When a commercially available electronic copying machine was used, continuous copying of 150,000 sheets was carried out under the conditions of a temperature of 35 ° C. and a humidity of 85%, and a clear image could not be obtained. The number of copies was evaluated.

The results of the above performance evaluations are shown in Table 5.

[0070]

[Table 5]

[0071]

As shown in Test Examples and Comparative Test Examples, the toner of the present invention shows almost no decrease in viscosity during toner production, good low-temperature fixability and offset resistance, and image stability in continuous copying. Is also good.

Continued front page    F-term (reference) 2H005 AA01 AB02 CA08 EA03 EA06                       EA07

Claims (5)

[Claims] 1. A gel content of 0.3% by weight or less, a weight average molecular weight (Mw) measured by GPC (gel permeation chromatography) of 3,000 to 20,000, and a number average molecular weight (Mn) of 1, 000 to 5,000, these ratios (Mw / Mn) are 2 to 10 and 1 in the flow tester.
A polyester resin (A) having a falling temperature (T1 / 2) of 80 to 140 ° C., a gel content of 2% by weight or less, and a weight average molecular weight (Mw) measured by a GPC method of 200,000 to 2,
, 000,000, number average molecular weight (Mn) is 5,000 to 2
000, the ratio (Mw / Mn) of these is 10 to 400
And the 1/2 drop temperature (T1 / 2) in the flow tester is 1
An electrophotographic toner comprising a binder resin containing a polyester resin (B) at 50 to 250 ° C. and a colorant. 2. The polyester resin (B) contains a dicarboxylic acid, a diol and a bifunctional epoxy compound as essential components, and the content of the bifunctional epoxy compound is 0.5.
The toner for electrophotography according to claim 1, which is a polyester resin obtained by using a raw material component of from about 2.5% by weight. 3. The polyester resin (B) is a polyester resin obtained by further using a raw material component containing 1 to 10% by weight of a monoepoxy compound having an alkyl group having 4 to 28 carbon atoms. Item 2. The electrophotographic toner according to Item 2. 4. A polyester resin (A) and a polyester resin (B) having a weight ratio (A) / (B) of 30/7.
The toner for electrophotography according to claim 1, which is used by mixing in the range of 0 to 70/30. 5. The polyester resin (B) is a polyester resin obtained by reacting a dicarboxylic acid as a raw material component with a diol containing 90 mol% or more of an aliphatic diol and / or an alicyclic diol. , Claim 1
The described electrophotographic toner.