JP2006113473A - Electrophotographic toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic toner excellent in both low-temperature fixability and storage stability, and to provide a method for manufacturing the same. <P>SOLUTION: The electrophotographic toner includes a crystalline polyester, an amorphous polyester, a colorant and a crystal-nucleation agent, 2Θ of wide-angle X-ray diffraction of which has a peak within a range of 14-26°, wherein the crystal-nucleation agent is at least one selected from the group consisting of a crystal-nucleation agent (A): a fatty acid amide whose melting point is from the melting point of the crystalline polyester to (the melting point)+100°C, a crystal-nucleation agent (B): a quinacridone compound whose average particle diameter is 1-200 nm, and a crystal-nucleation agent (C): a compound whose solubility in at least one alcohol having a content of ≥20 mol% in alcohol components as raw material monomers of the crystalline polyester is ≥0.2 wt.% at 50°C, and whose melting point is (the melting point of the crystalline polyester)+5°C or above (but the compound is neither fatty acid amide nor quinacridone compound). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electrophotographic toner used for developing a latent image formed in an electrophotographic method, an electrostatic recording method, an electrostatic printing method, and the like, and a method for producing the same.

The properties required for the toner include large low-temperature fixability and storage stability. Therefore, as an attempt for low-temperature fixability, many toners containing crystalline polyester and amorphous polyester as binder resins have been studied (see Patent Documents 1 and 2).
JP-A-1-289971 (Claim 1) JP 2000-222138 A (Claim 1)

  An object of the present invention is to provide an electrophotographic toner excellent in both low-temperature fixability and storage stability and a method for producing the same.

The present invention
[1] An electrophotographic toner comprising a crystalline polyester, an amorphous polyester, a colorant, and a crystal nucleating agent having a peak at a wide angle X-ray diffraction 2Θ in the range of 14 to 26 degrees, A nucleating agent is a crystal nucleating agent (A): a fatty acid amide having a melting point not lower than the melting point of the crystalline polyester and not higher than a melting point + 100 ° C.
Crystal nucleating agent (B): Quinacridone compound having an average particle size of 1 to 200 nm, and crystal nucleating agent (C): In the raw material monomer of the crystalline polyester, the content of alcohol in the alcohol component is 20 mol% or more. A compound whose solubility in at least one kind is 0.2% by weight or more at 50 ° C. and whose melting point is the melting point of the crystalline polyester + 5 ° C. or more (excluding fatty acid amides and quinacridone compounds)
An electrophotographic toner that is at least one selected from the group consisting of: and [2] a method for producing an electrophotographic toner according to [1] above, wherein at least the crystalline polyester and the crystal nucleating agent, The present invention relates to a method for producing an electrophotographic toner having a step of melt-kneading at a melting point of crystalline polyester + 5 ° C or higher.

  The toner for electrophotography of the present invention has an excellent effect of being excellent in both low temperature fixability and storage stability.

  As the crystalline polyester is more highly dispersed in the toner, the effect on the low-temperature fixability becomes greater. On the other hand, however, the crystalline polyester tends to collapse in the course of mixing and dispersing with amorphous polyester or the like, and the collapse of the crystalline structure can cause a decrease in the storage stability of the toner.

  Therefore, the present inventors have studied a means for highly dispersing the crystalline polyester without destroying the crystal structure in order to fully exhibit the effect of the crystalline polyester. It has been found that a crystalline chemical substance having a peak within a specific range acts as a crystal nucleating agent, and has a remarkable effect in promoting the crystallization of the crystalline polyester and suppressing the decrease in the crystallinity upon toner formation.

  Therefore, the electrophotographic toner of the present invention has a great feature in that it contains a crystal nucleating agent.

  The crystal nucleating agent in the present invention has a peak in the range of 2 to 26 of wide-angle X-ray diffraction of 14 to 26 degrees, preferably 20 to 25 degrees. Such a region is a region where the main signal of the crystalline polyester appears, and the substance in which the signal appears in this region is considered to have a crystal structure similar to that of the crystalline polyester, and thus promotes crystallization of the crystalline polyester. It is presumed to act effectively as a crystal nucleating agent.

Furthermore, from the viewpoint of further enhancing the function of promoting crystallization of crystalline polyester,
Requirement 1: having a crystal structure close to crystalline polyester,
Requirement 2: From the viewpoint of increasing the number of crystallinity, it is preferable to have fine dispersion in the crystalline polyester and Requirement 3: having a higher freezing point (melting point) than the crystalline polyester. Therefore, from these viewpoints, in the present invention,
Crystal nucleating agent (A): a fatty acid amide having a melting point not lower than the melting point of the crystalline polyester and not higher than + 100 ° C.
Crystal nucleating agent (B): Quinacridone compound having an average particle diameter of 1 to 200 nm, and crystal nucleating agent (C): Crystal nucleating agent (C): In the raw material monomer of the crystalline polyester, the content in the alcohol component is A compound having a solubility in at least one of 20 mol% or more of alcohol at 50 ° C of 0.2 wt% or more and a melting point of 5 ° C or more of the crystalline polyester (excluding fatty acid amides and quinacridone compounds)
At least one selected from the group consisting of is used as a crystal nucleating agent.

  The crystal nucleating agent (A) is a fatty acid amide having a crystal structure close to that of the crystalline polyester, and is easily melted during melt kneading, so that it can be finely dispersed in the crystalline polyester. In addition, since the melting point is higher than that of the crystalline polyester and the crystal nucleating agent crystallizes faster than the crystalline polyester, it tends to serve as a crystal nucleating agent.

  The fatty acid amide is preferably an alkylene bis fatty acid amide from the viewpoint of compatibility with the polyester. 2-8 are preferable and, as for carbon number of an alkylene group, 2-6 are more preferable. Moreover, 6-30 are preferable and, as for carbon number of the fatty acid group in fatty acid amide, 8-24 are more preferable. Suitable fatty acid amides in the present invention include ethylene bis stearic acid amide, hexamethylene bis lauric acid amide, ethylene bis lauric acid amide, hexamethylene bis stearic acid amide, etc. From the viewpoint of high crystallinity, ethylene Bisethylene bis stearamide is more preferred.

  The melting point of the fatty acid amide is not less than the melting point (Tm) ° C. and not more than (Tm + 100) ° C. of the crystalline polyester, and is preferably (Tm + 5) ° C. to (Tm + 70) ° C. from the viewpoint of dispersibility of the crystal nucleating agent and manifestation of the effect. . Furthermore, from the viewpoint of nucleating agent dispersibility, (Tm + 5) ° C. to (Tm + 40) ° C. is more preferable, and (Tm + 5) ° C. to (Tm + 30) ° C. is more preferable. On the other hand, from the viewpoint of expression of the effect of the crystal nucleating agent (easy setting of the nucleating agent), (Tm + 20) ° C. to (Tm + 70) ° C. is more preferable, and (Tm + 30) ° C. to (Tm + 60) ° C. is more preferable.

  The crystal nucleating agent (B) is a quinacridone compound having a crystal structure close to that of the crystalline polyester and having a higher freezing point than that of the crystalline polyester. The quinacridone compound does not dissolve in the crystalline polyester, but is finely dispersed in the crystalline polyester because of its small particle size.

  As the quinacridone compound, γ-type quinacridone, β-type quinacridone and the like are preferable, and β-type quinacridone is more preferable.

  The average particle size of the quinacridone compound is 1 to 200 nm, preferably 5 to 150 nm, more preferably 10 to 120 nm, and still more preferably 30 to 100 nm. Here, the average particle diameter refers to the number average particle diameter, and can be determined using, for example, a transmission electron microscope.

  The crystal nucleating agent (C) is finely dispersed in the crystalline polyester to exhibit a solubility of a specific amount or more in at least one raw material monomer of the crystalline polyester, the melting point is higher than the melting point of the crystalline polyester, Since the crystal nucleating agent crystallizes faster than the crystalline polyester, it tends to serve as a crystal nucleating agent.

  The crystal nucleating agent (C) has an alcohol component content of 20 mol% or more, preferably 40 mol% or more, more preferably 50 mol% or more, and still more preferably 60 mol% or more with respect to at least one kind of alcohol. Thus, at 50 ° C., it exhibits a solubility of 0.2% by weight or more, preferably 0.5 to 5% by weight. In addition, the solubility in this specification means the weight fraction of the solute in 100g of solutions.

  The melting point of the crystal nucleating agent (C) is not less than the melting point of the crystalline polyester + 5 (Tm + 5) ° C., preferably (Tm + 10) ° C. to (Tm + 200) ° C., more preferably (Tm + 20) ° C. to (Tm + 150) ° C.

  As the crystal nucleating agent (C), a sorbitol-based compound is preferable, and bis (p-methylbenzylidene) sorbitol is more preferable from the viewpoint of compatibility with the crystalline polyester.

  The particle size of the sorbitol-based compound is preferably 1 mm or less, and more preferably 0.5 mm or less.

  The content of the crystal nucleating agent is preferably 0.2% by weight or more from the viewpoint of exhibiting sufficient effects in the toner, and 7% by weight from the viewpoint of maintaining a high resin concentration in the toner and obtaining excellent fixability. The following is preferable, 0.4 to 5% by weight is more preferable, and 0.6 to 4% by weight is further preferable.

  The toner of the present invention contains at least a crystalline polyester and an amorphous polyester as a binder resin.

  In the present invention, “crystalline polyester” refers to a polyester having a crystallinity index of 0.6 to 1.5, preferably 0.8 to 1.2, and “amorphous polyester” refers to a crystallinity index of greater than 1.5 or 0.6. Polyester less than, preferably greater than 1.5. Here, the crystallinity index is a physical property that is an index of the degree of crystallization of the resin, and is defined by the ratio of the softening point to the maximum endothermic peak temperature (softening point / maximum endothermic peak temperature). is there. A resin having a crystallinity index exceeding 1.5 is amorphous, and a resin having a crystallinity index of less than 0.6 has low crystallinity and many amorphous portions. The degree of crystallization can be adjusted by the type and ratio of the raw material monomers, production conditions (for example, reaction temperature, reaction time, cooling rate) and the like. The highest endothermic peak temperature refers to the temperature of the peak on the highest temperature side among the observed endothermic peaks. If the maximum peak temperature is within 20 ° C from the softening point, the melting point is determined.

  Both the crystalline polyester and the amorphous polyester are obtained by using an alcohol component and a carboxylic acid component as raw material monomers and subjecting them to condensation polymerization.

  In the crystalline polyester, the alcohol component preferably contains a monomer that promotes the crystallinity of the resin, such as an aliphatic diol having 2 to 8 carbon atoms.

  Examples of the aliphatic diol having 2 to 8 carbon atoms include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, Examples include 1,7-heptanediol, 1,8-octanediol, neopentyl glycol, 1,4-butenediol, and α, ω-linear alkanediol is particularly preferable.

  From the viewpoint of high crystallinity, the content of the aliphatic diol having 2 to 8 carbon atoms is preferably 80 mol% or more, more preferably 85 mol% or more, and further preferably 90 mol% or more in the alcohol component. Furthermore, it is desirable that one aliphatic diol in them accounts for 70 mol% or more, preferably 80 to 95 mol% in the alcohol component. Among these, 1,4-butanediol is preferably contained in the alcohol component in an amount of preferably 60 mol% or more, more preferably 70 mol% or more, and even more preferably 80 mol% or more.

  As the carboxylic acid component, fumaric acid, adipic acid, oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, sebacic acid, azelaic acid, n-dodecyl succinic acid, n- Aliphatic dicarboxylic acids having 2 to 30 carbon atoms such as dodecenyl succinic acid, preferably 2 to 8; aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid; trimellitic acid And trivalent or higher polyvalent carboxylic acids such as pyromellitic acid. Among these, from the viewpoint of crystallinity, aliphatic dicarboxylic acids are preferable, and aliphatic dicarboxylic acids having 2 to 8 carbon atoms are preferable. In addition, although carboxylic acid, its anhydride, and its alkyl (C1-C3) ester are contained in a carboxylic acid component, In these, carboxylic acid is preferable.

  The content of the aliphatic dicarboxylic acid compound is preferably 70 mol% or more, more preferably 80 to 100 mol%, still more preferably 90 to 100 mol% in the carboxylic acid component.

  The molar ratio of the carboxylic acid component to the alcohol component (carboxylic acid component / alcohol component) in the crystalline polyester is preferably higher in alcohol component than in the carboxylic acid component when increasing the molecular weight of the crystalline polyester. Furthermore, from the viewpoint that the molecular weight of the polyester can be easily adjusted by distilling off the alcohol component during the reaction under reduced pressure, it is preferably 0.9 or more and less than 1, and more preferably 0.95 or more and less than 1.

  The polycondensation of the alcohol component and the carboxylic acid component in the production of the crystalline polyester can be performed, for example, in an inert gas atmosphere at a temperature of 120 to 230 ° C. using an esterification catalyst if necessary. it can. In order to increase the strength of the resin, all monomers are charged at once, or a divalent monomer is first reacted to reduce low molecular weight components, and then a trivalent or higher monomer is added and reacted. You may use the method of making it. Further, the reaction may be accelerated by reducing the pressure of the reaction system in the latter half of the polymerization.

  In order to obtain a higher molecular weight crystalline polyester, the molar ratio of the carboxylic acid component and the alcohol component is adjusted as described above, the reaction temperature is increased, the amount of the catalyst is increased, and the dehydration reaction is performed for a long time under reduced pressure. What is necessary is just to select reaction conditions, such as performing. In addition, under high power required for stirring, it is possible to produce a high-viscosity crystalline polyester having a high molecular weight. However, when producing without particularly selecting production equipment, the raw material monomer is a non-reactive low-viscosity resin. A method of reacting with a solvent is also an effective means.

  The softening point of the crystalline polyester is preferably from 70 to 140 ° C, more preferably from 105 to 130 ° C, from the viewpoint of low-temperature fixability.

  The melting point of the crystalline polyester is preferably 60 to 140 ° C., more preferably 70 to 130 ° C., and further preferably 80 to 120 ° C. from the viewpoint of fixability.

  Amorphous polyester is also obtained by polycondensation of an alcohol component and a carboxylic acid component as raw material monomers, similarly to crystalline polyester.

  The alcohol component in the amorphous polyester includes polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, etc. Formula (I):

(Wherein R is an alkylene group having 2 or 3 carbon atoms, x and y are positive numbers, and the sum of x and y is 1 to 16, preferably 1.5 to 5.0)
An aromatic diol such as an alkylene oxide adduct of bisphenol A represented by: an aliphatic diol such as ethylene glycol or propylene glycol; a trivalent or higher valent alcohol such as glycerin or pentaerythritol.

  Among the alcohol components, monomers that promote the amorphization of resins such as aromatic diols such as alkylene oxide adducts of bisphenol A are preferred, and from the viewpoint of chargeability, bisphenols represented by formula (I) are preferred. The content of the alkylene oxide adduct of A is preferably 50 mol% or more, more preferably 70 mol% or more, further preferably 90 mol% or more in the alcohol component.

  As the carboxylic acid component, aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid; oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, adipic acid, Aliphatic dicarboxylic acids such as sebacic acid, azelaic acid, n-dodecyl succinic acid and n-dodecenyl succinic acid; cycloaliphatic dicarboxylic acids such as cyclohexanedicarboxylic acid; trivalent or higher polyvalent carboxylic acids such as trimellitic acid and pyromellitic acid And anhydrides of these acids, alkyl (C1-C3) esters, and the like. Among these, aromatic carboxylic acid compounds are preferable from the viewpoint of chargeability. From the viewpoint of safety, aliphatic carboxylic acid compounds are preferred, and fumaric acid is more preferred. In addition, in this invention, a carboxylic acid compound points out dicarboxylic acid, its anhydride, and its alkyl (C1-C3) ester.

  Further, the alcohol component and the carboxylic acid component may appropriately contain a monovalent alcohol and a monovalent carboxylic acid compound from the viewpoint of adjusting the molecular weight.

  The polycondensation of the alcohol component and the carboxylic acid component in producing the amorphous polyester is performed at a temperature of 180 to 250 ° C., for example, in an inert gas atmosphere, if necessary, using an esterification catalyst. Can do.

  The softening point of the amorphous polyester is preferably 80 to 150 ° C, more preferably 85 to 145 ° C, and further preferably 90 to 140 ° C.

  The amorphous polyester is preferably composed of two kinds of amorphous polyesters having a softening point of preferably 10 ° C. or higher, more preferably 20 to 60 ° C. from the viewpoint of achieving both low-temperature fixability and offset resistance. The softening point of the low softening point polyester is preferably 80 to 120 ° C., more preferably 85 to 110 ° C. from the viewpoint of low-temperature fixability, and the softening point of the high softening point polyester is preferably from the viewpoint of offset resistance. Is 120 to 150 ° C, more preferably 130 to 145 ° C. The weight ratio of the high softening point polyester to the low softening point polyester (high softening point polyester / low softening point polyester) is preferably 20/80 to 80/20.

  The acid value of the amorphous polyester is preferably 1 to 50 mgKOH / g, more preferably 10 to 30 mgKOH / g. Further, the glass transition point is preferably 40 to 80 ° C, more preferably 50 to 70 ° C, from the viewpoints of pulverization and storage.

  The crystalline polyester and the amorphous polyester are preferably those using at least one common compound as a raw material monomer from the viewpoint of dispersibility of the crystalline polyester. Such a common compound is preferably a carboxylic acid component, fumaric acid and phthalic acid are more preferable, and fumaric acid is more preferable from the viewpoint of increasing the crystallinity of the crystalline polyester.

  The content of the crystalline polyester is preferably 3 to 40% by weight, more preferably 5 to 30% by weight, from the viewpoint of low-temperature fixability and storage stability in the toner.

  The weight ratio of crystalline polyester to amorphous polyester (crystalline polyester / amorphous polyester) is preferably from 3/97 to 50/50, more preferably from 5/95 to 35/65.

  In the present invention, a binder resin other than a polyester such as a vinyl resin, an epoxy resin, a polycarbonate, and a polyurethane may be used as the binder resin, but the total content of the polyester is 80% of the total amount of the binder resin. % By weight or more is preferable, and 90% by weight or more is more preferable.

  As the colorant, all of dyes and pigments used as toner colorants can be used, such as carbon black, phthalocyanine blue, permanent brown FG, brilliant first scarlet, pigment green B, rhodamine-B base, Solvent Red 49, Solvent Red 146, Solvent Blue 35, Quinacridone, Carmine 6B, Disazo Yellow and the like can be used alone or in combination of two or more. The toner of the present invention is a black toner, color Either toner or full color toner may be used. The content of the colorant is preferably 1 to 40 parts by weight and more preferably 3 to 10 parts by weight with respect to 100 parts by weight of the binder resin.

  Further, the raw material of the toner of the present invention includes a release agent, a charge control agent, a magnetic powder, a conductivity modifier, an extender pigment, a reinforcing filler such as a fibrous substance, an antioxidant, an anti-aging agent, and an improvement in fluidity. Additives such as agents and cleaning improvers may be used as appropriate.

  The toner of the present invention may be obtained by any conventionally known method such as a kneading and pulverizing method, an emulsion phase inversion method, or a polymerization method, but it is easy to produce and the effect of the present invention is remarkable. Therefore, a pulverized toner obtained by a kneading pulverization method is preferable. When the toner is obtained by the kneading and pulverization method, for example, a binder resin such as crystalline polyester or amorphous polyester, a colorant, and additives such as a charge control agent used as necessary are sealed. It can be manufactured by melt-kneading with a kneader or uniaxial or biaxial extruder, cooling, pulverizing, and classifying. In the emulsification phase inversion method, for example, after dissolving or dispersing the raw materials in an organic solvent, Can be made into an emulsion by adding, and then separated and classified. Further, a fluidity improver such as hydrophobic silica may be externally added to the surface of the toner as necessary.

  When the toner of the present invention is produced by the kneading and pulverization method, from the viewpoint of improving the dispersibility of the crystal nucleating agent, at least the crystalline polyester and the crystal nucleating agent are added to the melting point of the crystalline polyester + 5 (Tm + 5) ° C. As described above, it is preferable to have a step of melt-kneading at a temperature of (Tm + 10) ° C. or higher, more preferably (Tm + 20) ° C. or higher and (Tm + 100) ° C. or lower.

  In addition, raw materials such as binder resins such as crystalline polyester and amorphous polyester, crystal nucleating agents, coloring agents, and additives such as charge control agents used as needed are Henschel mixers before melt kneading. It is preferable to pre-mix uniformly with this mixer. The addition timing of the crystal nucleating agent is not particularly limited, but from the viewpoint of improving the dispersibility of the crystal nucleating agent, the crystal nucleating agent is also preferably added during the preliminary mixing of the raw materials.

The volume median particle size (D ₅₀ ) of the toner of the present invention is preferably 3 to 15 μm. In the present specification, the volume-median particle size (D ₅₀ ) means a particle size at which the cumulative volume frequency calculated by the volume fraction is 50% when calculated from the smaller particle size.

  When the toner of the present invention contains a magnetic fine powder, it is used alone as a developer, and when it does not contain a magnetic fine powder, it is used as a non-magnetic one-component developer or mixed with a carrier to develop a two-component developer. It can be used as an agent.

[Maximum endothermic peak temperature and melting point]
Using a differential scanning calorimeter (Seiko Denshi Kogyo Co., Ltd., DSC210), the temperature is raised to 200 ° C, and the sample cooled to 0 ° C at a temperature drop rate of 10 ° C / min is measured at a temperature rise rate of 10 ° C / min . Among the observed endothermic peaks, the temperature of the peak on the highest temperature side is defined as the highest endothermic peak temperature. If the maximum peak temperature is within 20 ° C. from the softening point, the melting point is set, and the peak having a difference from the softening point exceeding 20 ° C. is a peak due to glass transition.

[Glass transition point]
Using a differential scanning calorimeter (Seiko Denshi Kogyo Co., Ltd., DSC210), the temperature is raised to 200 ° C, and the sample cooled to 0 ° C at a temperature drop rate of 10 ° C / min is measured at a temperature rise rate of 10 ° C / min . If the binder resin contains an amorphous resin in addition to the crystalline polyester, or if the crystalline polyester contains an amorphous part, the peak temperature observed at a temperature lower than the maximum endothermic peak temperature or the endothermic The temperature at the intersection of the base line extension below the maximum peak temperature and the tangent line indicating the maximum slope from the peak rise to the peak apex is read as the glass transition point.

[Crystallinity index]
The crystallinity index is calculated as the degree of crystallinity from the following formula using the softening point and the maximum peak temperature of endotherm measured according to the above.
Crystallinity index = softening point / maximum endothermic peak temperature

[Softening point]
Using a Koka type flow tester (CFT-500D, manufactured by Shimadzu Corporation), a 1 g sample was heated at a heating rate of 6 ° C / min. A nozzle with a thickness of 1 mm is pushed out, thereby drawing a plunger tester's descent amount (flow value) -temperature curve, and when the height of the S-shaped curve is h, the temperature corresponding to h / 2 (resin The temperature at which half flows out) is taken as the softening point.

[Acid value]
Measured by the method of JIS K0070.

[Wide-angle X-ray diffraction]
Measuring device: Rigaku Denki Kogyo Co., Ltd., wide-angle X-ray diffractometer
X-ray tube: Cu tube 40kV-120mA
Acquisition condition: 0.01 ° / step, scan speed 1 ° / min.

Production Example 1 of Crystalline Polyester
After the raw material monomers shown in Table 1 were placed in a 5-liter four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple, and reacted at 200 ° C until no terephthalic acid particles were observed. The mixture was further reacted at 8.3 kPa for 3 hours to obtain a resin a.

Production Example 2 of Crystalline Polyester
The raw material monomers shown in Table 1, 4 g of dibutyltin oxide and 1 g of hydroquinone were placed in a 5-liter four-necked flask equipped with a nitrogen introduction tube, dehydration tube, stirrer and thermocouple, and reacted at 160 ° C for 5 hours. Then, the temperature was raised to 200 ° C. and reacted for 1 hour, and further reacted at 8.3 kPa until the desired crystallinity index was reached to obtain resin b.

Production Example 1 of Amorphous Polyester
Raw material monomers other than trimellitic anhydride shown in Table 2 and 4 g of dibutyltin oxide are placed in a 5-liter four-necked flask equipped with a nitrogen inlet tube, dehydrator tube, stirrer and thermocouple, and are heated at 230 ° C for 20 hours. After the reaction, the reaction was performed at 8.3 kPa for 1 hour. Further, trimellitic anhydride was added at 210 ° C. and reacted until the desired softening point was reached to obtain resins A and B.

Production Example 2 of Amorphous Polyester
Raw material monomers other than trimellitic anhydride shown in Table 2, 4 g of dibutyltin oxide and 1 g of hydroquinone were placed in a 5-liter four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple at 200 ° C. After reacting for 8 hours, it was reacted at 8.3 kPa for 1 hour. Further, trimellitic anhydride was added at 210 ° C. and reacted until the softening point was reached to obtain Resin C.

Production Example 3 of Amorphous Polyester
Raw material monomers other than trimellitic anhydride shown in Table 2 and 4 g of dibutyltin oxide are placed in a 5-liter four-necked flask equipped with a nitrogen inlet tube, dehydrator tube, stirrer and thermocouple, and are heated at 230 ° C for 20 hours. And then reacted at 8.3 kPa for 1 hour. Furthermore, trimellitic anhydride was added at 210 ° C. and reacted until the softening point was reached. Furthermore, after adding 912 g of resin b and stirring for 1 hour, it was made to react at 8.3 kPa for 1 hour, and resin D was obtained.

Examples 1-11, Comparative Examples 1-5
Binder resin, crystal nucleating agent, carbon black “Monarch 880” (Cabot) 4.0 parts by weight, cyan pigment “ECB-301” (Daiichi Seika) 0.3 parts by weight, charge control agent “Bontron” 1 part by weight of "S-34" (made by Orient Chemical Co., Ltd.), 2.0 parts by weight of polypropylene wax "NP-055" (made by Mitsui Chemicals) and 2.0 parts by weight of "Carnauba Wax C1" (made by Kato Yoko Co., Ltd.) using a Henschel mixer After thorough mixing, the mixture was melt kneaded using a co-rotating twin screw extruder having a total length of 1560 mm, a screw diameter of 42 mm, and a barrel inner diameter of 43 mm. The barrel set temperature was 100 ° C. (kneading temperature 120-140 ° C.), the screw rotation speed was 200 rotations / minute, the mixture supply speed was 10 kg / hour, and the average residence time was about 18 seconds.

  The obtained melt-kneaded product was cooled and coarsely pulverized, and then pulverized and classified by a jet mill to obtain a powder having a volume average particle size of 8.5 μm.

  To the obtained powder, 0.5 part by weight of hydrophobic silica “R-972” (manufactured by Nippon Aerosil Co., Ltd.) was added as an external additive and mixed with a Henschel mixer to obtain a toner.

  Only in Example 5, after melt-kneading, the obtained melt-kneaded product was kept at 50 ° C. for 7 days, and then cooled and coarsely ground.

Test Example 1 [low temperature fixability]
Toner was mounted on a copier “AR-505” (manufactured by Sharp Corporation), and an unfixed image having a solid image portion of 2 cm × 12 cm (toner adhesion amount: 0.5 mg / cm ² ) was obtained. Using a fixing machine (fixing speed: 100 mm / sec) with an improved fixing machine for the copier “AR-505” (manufactured by Sharp Corporation) that can be fixed outside the machine, the fixing temperature ranges from 90 ° C to 240 ° C. The unfixed image was fixed while gradually increasing to 5 ° C by 5 ° C.

“Unicelohan tape” (Mitsubishi Pencil Co., Ltd., width: 18 mm, JIS Z-1522) was applied to the fixed image, passed through a fixing roller set at 30 ° C., and then the tape was peeled off. The optical reflection density before and after the tape is peeled off is measured using a reflection densitometer “RD-915” (manufactured by Macbeth), and the ratio between the two (before sticking / after peeling) first exceeds 70%. The low temperature fixability was evaluated according to the following evaluation criteria with the roller temperature as the minimum fixing temperature. The results are shown in Table 3. The paper used for the fixing test is “CopyBond SF-70NA” (manufactured by Sharp Corporation, 75 g / m ² ).

〔Evaluation criteria〕
A: Minimum fixing temperature is less than 140 ° C. ○: Minimum fixing temperature is 140 ° C. or higher and lower than 150 ° C. ×: Minimum fixing temperature is 150 ° C. or higher.

Test Example 2 [Preservation]
4 g of toner was left for 48 hours in an environment of a temperature of 50 ° C. and a humidity of 80%. The state of the toner after standing was observed, and the storage stability was evaluated according to the following evaluation criteria. The results are shown in Table 3.

〔Evaluation criteria〕
(Double-circle): Aggregation is not recognized at all.
A: Almost no aggregation is observed.
X: It is lump.

The crystal nucleating agents used in Examples and Comparative Examples are as follows (2Θ values of wide angle X-ray diffraction are shown in Table 4).
Ethylene bis-stearic acid amide: Kao WAX EB (manufactured by Kao Corporation), melting point 152 ° C
γ-type quinacridone:
γ Pigment Violet No. 19 (manufactured by Dainichi Seika), average particle size 60nm
β-type quinacridone:
β Pigment Violet No. 19 (manufactured by Dainichi Seika), average particle size 60nm
Bis (p-methylbenzylidene) sorbitol:
Gerol MD (manufactured by Shin Nippon Rika), melting point 260 ° C
Solubility in 1,6-hexanediol 1.2% by weight
Hexamethylenebislauric acid amide: produced by the method described later, melting point 152 ° C.
2,2'-Methylenebis (4,6-di-t-butylphenyl) sodium phosphate:
Asahi Denka Kogyo Co., Ltd. (ADK STAB NA-11), melting point 220 ° C,
Solubility in 1,6-hexanediol solubility 0.1% by weight
Silica: Aerosil 50 (manufactured by Nippon Aerosil Co., Ltd.), average particle size 30 nm

Method for producing hexamethylenebislauric acid amide 2288 g of lauric acid is placed in a 5-liter four-necked flask equipped with a nitrogen inlet tube, a dehydrating tube, a stirrer and a thermocouple, and 700 g of hexamethylenediamine is added at 80 to 120 ° C. It was added dropwise over time. The mixture was dehydrated while being heated to 200 ° C., and after the temperature was raised, the dehydration reaction was carried out over 4 hours, followed by extraction and cooling to obtain hexamethylenebislauric acid amide.

  From the above results, it can be seen that, compared with the toner of the comparative example, all of the toners of the examples sufficiently exert the fixing effect by the crystalline polyester without impairing the storage stability.

  The toner for electrophotography of the present invention is suitably used for developing a latent image formed in electrophotography, electrostatic recording method, electrostatic printing method and the like.

Claims (7)

An electrophotographic toner comprising a crystalline polyester, an amorphous polyester, a colorant, and a crystal nucleating agent having a peak in a range of 14 to 26 degrees of 2Θ of wide-angle X-ray diffraction, wherein the crystal nucleating agent is Crystal nucleating agent (A): a fatty acid amide having a melting point of not less than the melting point of the crystalline polyester and not more than the melting point + 100 ° C.
Crystal nucleating agent (B): Quinacridone compound having an average particle size of 1 to 200 nm, and crystal nucleating agent (C): In the raw material monomer of the crystalline polyester, the content of alcohol in the alcohol component is 20 mol% or more. A compound whose solubility in at least one kind is 0.2% by weight or more at 50 ° C. and whose melting point is the melting point of the crystalline polyester + 5 ° C. or more (excluding fatty acid amides and quinacridone compounds)
An electrophotographic toner which is at least one selected from the group consisting of:   2. The electrophotographic toner according to claim 1, wherein the crystalline polyester and the amorphous polyester use at least one common compound as a raw material monomer.   The electrophotographic toner according to claim 1 or 2, wherein the content of the crystalline polyester is 3 to 40% by weight in the toner.   The toner for electrophotography according to any one of claims 1 to 3, wherein the crystal nucleating agent (A) is an alkylene (2 to 8 carbon atoms) bisfatty acid amide.   The toner for electrophotography according to claim 1, wherein the crystal nucleating agent (C) is a sorbitol compound.   The toner for electrophotography according to any one of claims 1 to 5, wherein the content of the crystal nucleating agent is 0.2 to 7% by weight in the toner.   The method for producing an electrophotographic toner according to any one of claims 1 to 6, comprising a step of melt-kneading at least the crystalline polyester and the crystal nucleating agent at a temperature of the melting point of the crystalline polyester + 5 ° C or higher. Of manufacturing toner.