JP5084482B2 - Toner for electrophotography - Google Patents

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 toner.

  From the viewpoint of low-temperature fixability of toners, a large number of toners in which a crystalline polyester excellent in low-temperature fixability is used in combination with an amorphous polyester have been studied, and low-temperature fixing is achieved by increasing the compatibility between the crystalline polyester and the amorphous polyester. It is known that the property can be improved.

However, if the compatibility between the two is too high, there is a problem that the heat-resistant storage stability and crystallinity of the toner are deteriorated. In order to solve this problem, a technique of adding a heat treatment process at a specific temperature to a toner manufacturing process has been disclosed (see Patent Documents 1 to 4).
JP 2005-308995 A JP 2006-138919 A JP 2007-72333 A JP 2006-65015 A

  According to the prior art, it is possible to improve the low-temperature fixability by increasing the compatibility between the crystalline polyester and the amorphous polyester, and to improve the heat-resistant storage stability by heat treatment. However, since these are contradictory properties, a toner having a high level of low-temperature fixability and heat-resistant storage required for high speed and high image quality in recent years has not been obtained.

  An object of the present invention is to provide an electrophotographic toner capable of achieving both low-temperature fixability and heat-resistant storage stability, and a method for producing the toner.

  As a result of repeated studies to solve the above problems, the present inventors have found that a toner for electrophotography containing a binder resin containing polyester has a specific peak temperature and a specific peak observed in differential scanning calorimetry. When the amount of heat satisfies a specific relationship, it has been found that both low-temperature fixability and heat-resistant storage stability can be achieved, and the present invention has been completed.

That is, the present invention
[1] It contains a binder resin containing polyester and has the formula (i):
2.0 ≤ T1-T2 ≤ 9.0 (i)
[In the formula, T1 indicates the maximum endothermic peak temperature (° C) in differential scanning calorimetry under the condition (A), and T2 indicates the maximum endothermic temperature (° C) in differential scanning calorimetry under the condition (B)]
And formula (ii):
Q3 / Q2 × 100 ≦ 30 (ii)
[In formula, Q2 is the maximum peak calorie (J / g) of endothermic measurement in differential scanning calorimetry under condition (B), and Q3 is the endotherm observed at T2 ± 1 (° C) in differential scanning calorimetry under condition (C). (Shows peak heat value (J / g))
Satisfying the relationship of electrophotographic toner,
Condition (A): Measurement condition from 0 ° C to 150 ° C at a temperature increase rate of 10 ° C / min (B): Measurement condition from 0 ° C to 150 ° C at a temperature increase rate of 100 ° C / min (C): Temperature increase rate of 10 ° C After heating from 0 ° C to 150 ° C at a cooling rate of 100 ° C / min, cooling from 150 ° C to 0 ° C at a cooling rate of 100 ° C / min, measuring from 0 ° C to 150 ° C at a heating rate of 100 ° C / min and [2] [1] The method for producing an electrophotographic toner according to [1], wherein the toner composition containing a polyester-containing binder resin is maintained at 40 to 80 ° C. [Step (1)] It relates to a manufacturing method.

  The toner for electrophotography of the present invention has an excellent effect that both low-temperature fixability and heat-resistant storage stability can be achieved.

The toner for electrophotography of the present invention contains a binder resin containing polyester and has the formula (i):
2.0 ≤ T1-T2 ≤ 9.0 (i)
[In the formula, T1 indicates the maximum endothermic peak temperature (° C) in differential scanning calorimetry under the condition (A), and T2 indicates the maximum endothermic temperature (° C) in differential scanning calorimetry under the condition (B)]
And formula (ii):
Q3 / Q2 × 100 ≦ 30 (ii)
[In formula, Q2 is the maximum peak calorie (J / g) of endothermic measurement in differential scanning calorimetry under condition (B), and Q3 is the endotherm observed at T2 ± 1 (° C) in differential scanning calorimetry under condition (C). (Shows peak heat value (J / g))
Condition (A): Measurement condition from 0 ° C to 150 ° C at a temperature increase rate of 10 ° C / min (B): Measurement condition from 0 ° C to 150 ° C at a temperature increase rate of 100 ° C / min (C): Temperature increase rate of 10 ° C Heats from 0 ° C to 150 ° C at / min, cools from 150 ° C to 0 ° C at a cooling rate of 100 ° C / min, and further satisfies the measurement relationship from 0 ° C to 150 ° C at a heating rate of 100 ° C / min In particular, it has a great feature. In the present specification, the “maximum endothermic peak temperature” refers to the peak temperature (° C.) of the highest endothermic peak among the observed endothermic peaks, and the “maximum endothermic heat amount” refers to the peak. Of peak heat (J / g).

  Toner having a binder resin crystal structure dispersed, for example, a toner containing crystalline polyester and amorphous polyester, for example, when differential scanning calorimetry is performed from 0 ° C. to 150 ° C. at a heating rate of 10 ° C./min, After the peak of the exothermic reaction is observed, the peak of the endothermic reaction (the peak temperature of the peak is T1 (° C.)) is observed. This is considered to be an exothermic reaction caused by the growth of binder resin crystals in the toner due to the heating accompanying the measurement, and an endothermic reaction caused by melting of the grown crystals. On the other hand, when the same toner is subjected to, for example, differential scanning calorimetry from 0 ° C. to 150 ° C. at a rate of temperature increase of 100 ° C./min, the peak of the endothermic reaction (the peak of the endothermic reaction is not observed). The peak temperature of the peak is T2 (° C.). This is because the temperature rise rate is fast, so crystal growth does not occur due to heating accompanying measurement, and the crystals themselves present in the toner are melted, and T2 (° C) is inherent in the toner. It can be regarded as the melting point of the existing crystals.

  In addition, T1 (° C.) is shifted to a higher temperature than T2 (° C.) because crystallization is promoted by heating by measurement, and has a relationship of 0 ≦ T1-T2. In general, it is already known that the melting point of a crystal decreases as the size of the crystal decreases. Therefore, the larger the difference in peak temperature observed in the above measurement, that is, T1−T2 (° C.), the smaller the size of crystals originally present in the toner. The smaller the size of the crystals present in the toner, the higher the dispersibility of the crystals in the toner, which is considered to indicate excellent low-temperature fixability. On the other hand, when T1-T2 (° C.) is small, it means that the size of crystals in the toner is large, which suggests that the toner contains large crystals and the fixability is poor. Therefore, in the present invention, 2.0 ≦ T1-T2, 2.5 ≦ T1-T2 is preferable, and 3.0 ≦ T1-T2 is more preferable.

  On the other hand, the microcrystals present in the toner have a filler effect and greatly contribute to improving the heat resistant storage stability of the toner. However, if the size of the crystal becomes too small, the filler effect is not sufficiently exhibited, and the crystal acts on the contrary as a plasticizer, thereby deteriorating the heat resistant storage stability of the toner. For this reason, when T1-T2 (° C.) is too large, it is considered that the heat-resistant storage stability is deteriorated because the crystals originally present in the toner are too small. Therefore, in the present invention, T1-T2 ≦ 9.0, T1-T2 ≦ 8.5 is preferable, T1-T2 ≦ 8.0 is more preferable, and T1-T2 ≦ 7.5 is more preferable.

From the above, the toner of the present invention has the formula (i):
2.0 ≤ T1-T2 ≤ 9.0 (i)
[In the formula, T1 indicates the maximum endothermic peak temperature (° C) in differential scanning calorimetry under the condition (A), and T2 indicates the maximum endothermic temperature (° C) in differential scanning calorimetry under the condition (B)]
Is satisfied, preferably 2.5 ≦ T1-T2 ≦ 8.0, and more preferably 3.0 ≦ T1-T2 ≦ 7.5. The conditions (A) and (B) are as follows.
Condition (A): Measured from 0 ° C. to 150 ° C. at a temperature rising rate of 10 ° C./min. Condition (B): Measured from 0 ° C. to 150 ° C. at a temperature rising rate of 100 ° C./min. It means that the toner is finely dispersed in the toner without being compatibilized. Thus, it is considered that both low-temperature fixability and heat-resistant storage stability can be realized.

The toner of the present invention is represented by the formula (ii):
Q3 / Q2 × 100 ≦ 30 (ii)
[In formula, Q2 is the maximum peak calorie (J / g) of endothermic measurement in differential scanning calorimetry under condition (B), and Q3 is the endotherm observed at T2 ± 1 (° C) in differential scanning calorimetry under condition (C). (Shows peak heat value (J / g))
Satisfies the relationship expressed by The conditions (B) and (C) are as follows.
Condition (B): From 0 ° C. to 150 ° C. at a heating rate of 100 ° C./min. Condition (C): Heating from 0 ° C. to 150 ° C. at a heating rate of 10 ° C./min, 150 at a cooling rate of 100 ° C./min. After cooling from 0 ℃ to 0 ℃, measure from 0 ℃ to 150 ℃ at a heating rate of 100 ℃ / min.

  The maximum peak calorific value of the endotherm observed when the differential scanning calorimetry is performed on the toner containing crystals under the above condition (B) is due to melting of the crystals originally present in the toner. Further, the endothermic peak calorific value observed when the differential scanning calorimetry is performed on the toner under the above condition (C) is that the crystals originally present in the toner are melted, and the newly formed crystals after cooling are melted. It is accompanied. That is, in this measurement, the crystal part of the binder resin melts due to the initial temperature rise (temperature increase rate 10 ° C./min) at the time of measurement, so the crystals originally present in the toner disappear, and after cooling In the second temperature increase measurement (temperature increase rate 100 ° C./min), an endothermic peak at T2 ± 1 (° C.) is hardly observed. Therefore, in the present invention, the toner of the present invention satisfies the relationship represented by Q3 / Q2 × 100 ≦ 30, preferably 0 ≦ Q3 / Q2 × 100 ≦ 29.0, more preferably 0 ≦ Q3 / Q2 ×. 100 ≦ 28.0, more preferably 0 ≦ Q3 / Q2 × 100 ≦ 25.0 is satisfied.

  On the other hand, even in a toner having no crystal part of the binder resin, for example, an endothermic peak due to wax may be observed as a peak having the largest endothermic amount among the observed endothermic peaks. Even if the toner is subjected to heat treatment or cooling treatment before differential scanning calorimetry as described above, such a peak does not fluctuate greatly because wax is not compatible with other binder resin components in the toner. Therefore, it is clear that Q2 (J / g) and Q3 (J / g) defined by the above formula (ii) are not significantly different and satisfy the relationship of formula (ii) There is no.

  The toner of the present invention contains a binder resin containing polyester.

  As the polyester in the present invention, it is preferable to use a crystalline polyester and an amorphous polyester in combination from the viewpoint of low-temperature fixability of the toner.

  The crystallinity of the resin is represented by the ratio between the softening point and the highest endothermic peak temperature in a differential scanning calorimeter (DSC), that is, the crystallinity index defined by the softening point / the highest endothermic peak temperature. When the ratio exceeds 1.5, the resin is amorphous. When the ratio is less than 0.6, the crystallinity is low and there are many amorphous portions. The crystallinity of the resin 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. 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. A resin less than, preferably greater than 1.5. 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 set, and the peak having a difference from the softening point exceeding 20 ° C. is a peak due to glass transition.

  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 polycondensation. In the present invention, from the viewpoint of improving the compatibility, the crystalline polyester The amorphous polyester is preferably a polyester obtained by using an alcohol component containing an aliphatic diol having 2 to 8 carbon atoms. This is because the compatibility of the monomer structures constituting the respective polyesters increases the compatibility, and even when the crystalline polyester is added, it can be finely dispersed during melting. As a result, it is presumed that even if the content of the crystalline polyester is increased, the toner has excellent fixability, and from the viewpoint of the filler effect of the crystals, the heat resistant storage stability is also improved.

  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, 1,7-heptanediol, 1,8-octanediol, neopentyl glycol and the like may be mentioned, and these may be contained alone or in admixture of two or more. Among these, from the viewpoint of promoting crystallinity, the crystalline polyester is preferably α, ω-linear alkanediol, more preferably 1,4-butanediol and 1,6-hexanediol, and 1,6 -Hexanediol is more preferred. On the other hand, in the amorphous polyester, the same aliphatic diol as that of the crystalline polyester can be used, but from the viewpoint of inhibiting the crystallinity, it is preferable to further contain a branched aliphatic diol. Of these, neopentyl glycol is more preferable.

  From the viewpoint of high crystallinity, the content of the aliphatic diol having 2 to 8 carbon atoms in the crystalline polyester is preferably 70 mol% or more, more preferably 80 mol% or more, and 85 mol% or more in the alcohol component. Is more preferable, and 90 mol% or more is more preferable. Further, when two or more kinds of aliphatic diols having 2 to 8 carbon atoms are used, one kind of the aliphatic diol in them contains 70 mol% or more, preferably 80 to 95 mol% in the alcohol component. It is desirable to occupy.

  The content of the aliphatic diol having 2 to 8 carbon atoms in the amorphous polyester is preferably 50 mol% or more in the alcohol component from the viewpoint of dispersibility of the crystalline polyester in the amorphous polyester. More preferably, mol% is more preferable, and 70-90 mol% or more is further more preferable. Among these, the content of the aliphatic diol having a branched chain is preferably 10 to 60 mol%, more preferably 20 to 50 mol% or more in the alcohol component.

  In the present invention, in addition to the aliphatic diol having 2 to 8 carbon atoms, other alcohols may be appropriately contained as long as the effects of the present invention are not impaired. Other alcohols include those represented by formula (I):

(In the formula, RO is an oxyalkylene group, R is an ethylene and / or propylene group, x and y represent the number of added moles of alkylene oxide, each being a positive number, and the average of the sum of x and y) (The value is preferably 1-16, more preferably 1-8, and even more preferably 1.5-4)
It is preferable that the alkylene oxide addition product of bisphenol A represented by these is used as an alcohol component in an amorphous polyester.

  Examples of alkylene oxide adducts of bisphenol A represented by the formula (I) include polyoxypropylene-2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene-2,2-bis (4-hydroxyphenyl) Examples thereof include alkylene (2 to 3 carbon) oxide (average number of added moles 1 to 16) adducts of bisphenol A such as propane.

  Since the amorphous polyester using the alkylene oxide adduct of bisphenol A has low compatibility with the crystalline polyester from the viewpoint of the monomer structure, the dispersibility of the crystals decreases as the amount of the crystalline polyester added increases. The low temperature fixability of the toner deteriorates. Therefore, the content of the alkylene oxide adduct of bisphenol A in the amorphous polyester is preferably from 0 to 70 mol%, preferably from 0 to 50 mol, from the viewpoint of achieving both low temperature fixability and heat resistant storage stability of the toner. % Or more is more preferable.

  The carboxylic acid compound contained in the carboxylic acid component includes 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- Aliphatic dicarboxylic acids having 2 to 30 carbon atoms, preferably 2 to 8 carbon atoms such as dodecyl succinic acid and n-dodecenyl succinic acid; Aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid; Dicarboxylic acid: Trivalent or higher polyvalent carboxylic acids such as trimellitic acid and pyromellitic acid, anhydrides of these acids, and alkyl (C1-3) esters of acids. Among these, an aliphatic dicarboxylic acid compound is preferable, and in the crystalline polyester, an aliphatic dicarboxylic acid compound having 2 to 8 carbon atoms is more preferable, and fumaric acid is more preferable from the viewpoint of crystallinity. In addition, the acids as described above, anhydrides of these acids, and alkyl esters of the acids are collectively referred to as carboxylic acid compounds in this specification.

  The content of the aliphatic dicarboxylic acid compound having 2 to 8 carbon atoms in the crystalline polyester is preferably 70 mol% or more, more preferably 80 mol% or more, further preferably 80 to 100 mol%, in the carboxylic acid component, 90 More preferred is ˜100 mol%.

  The content of the aliphatic dicarboxylic acid compound in the amorphous polyester 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 crystalline polyester preferably has an aliphatic diol having 2 to 8 carbon atoms in an amount of 80 mol% or more, more preferably 90 mol% from the viewpoint of enhancing crystallization and achieving both low temperature fixability and heat resistant storage stability of the toner. It is desirable to perform polycondensation of the alcohol component contained above and a carboxylic acid component containing an aliphatic dicarboxylic acid compound having 2 to 8 carbon atoms, preferably at least 80 mol%, more preferably at least 90 mol%.

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

  A monovalent alcohol may be appropriately contained in the alcohol component, and a monovalent carboxylic acid compound may be appropriately contained in the carboxylic acid component from the viewpoint of adjusting the molecular weight.

  Polyester is obtained by polycondensing an alcohol component and a carboxylic acid component, for example, in an inert gas atmosphere, if necessary in the presence of an esterification catalyst such as tin (II) octylate or tertiary butyl catechol. . The reaction temperature is preferably 120 to 230 ° C. in the production of crystalline polyester, and 180 to 250 ° C. in the production of amorphous polyester.

  In the production of crystalline polyester, all monomers are charged together to increase the strength of the resin, or divalent monomers are first reacted in order to reduce low molecular weight components. You may use methods, such as adding a monomer and making it react. 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 catalyst is increased, and dehydration is performed for a long time under reduced pressure. What is necessary is just to select reaction conditions, such as performing reaction. 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 total amount of the esterification catalyst in the reaction system is preferably 0.05 to 1 part by weight, more preferably 0.1 to 0.8 part by weight based on 100 parts by weight of the total amount of the alcohol component and the carboxylic acid component.

  The maximum endothermic peak temperature in the DSC measurement of the crystalline polyester is preferably 70 to 125 ° C., more preferably 80 to 125 ° C., and still more preferably 90 to 120 from the viewpoints of toner fixing property, heat resistant storage stability and durability. ° C. In the present specification, the maximum peak temperature of endotherm is measured by the method described in Examples described later.

  The softening point of the crystalline polyester is preferably from 70 to 140 ° C, more preferably from 80 to 130 ° C, and even more preferably from 105 to 130 ° C, from the viewpoint of low-temperature fixability of the toner. In the present specification, the softening point is measured by the method described in Examples described later.

  The softening point of the amorphous polyester is preferably 80 to 160 ° C, more preferably 85 to 150 ° C, and further preferably 90 to 145 ° C.

  The acid value of the amorphous polyester is preferably 1 to 60 mgKOH / g, more preferably 1 to 55 mgKOH / g, and further preferably 10 to 55 mgKOH / g. The glass transition point is preferably 40 to 80 ° C., more preferably 50 to 70 ° C., from the viewpoints of toner pulverization properties and heat-resistant storage stability. In this specification, an acid value and a glass transition point are measured by the method as described in the below-mentioned Example.

  The content of the crystalline polyester is preferably 5 to 30% by weight, more preferably 5 to 25% by weight, and further 7 to 25% by weight in the binder resin from the viewpoint of low-temperature fixability and heat-resistant storage stability of the toner. preferable.

  The content of the amorphous polyester is preferably 70 to 95% by weight and more preferably 75 to 93% by weight in the binder resin from the viewpoint of low-temperature fixability and heat-resistant storage stability of the toner.

  The weight ratio of crystalline polyester to amorphous polyester (crystalline polyester / amorphous polyester) is preferably from 3/97 to 40/60, more preferably from 5/95 to 30/70.

  In the present invention, the polyester may be a polyester modified to such an extent that the characteristics are not substantially impaired. Examples of the modified polyester include grafting and blocking with phenol, urethane, epoxy and the like by the methods described in JP-A-11-133668, JP-A-10-239903, JP-A-8-20636, and the like. And a composite resin having two or more kinds of resin units including a polyester unit.

  In the toner of the present invention, in addition to the polyester, other binder resins may be appropriately contained within a range that does not impair the effects of the present invention. Examples of other binder resins include binder resins other than polyesters such as vinyl resins, epoxy resins, polycarbonates, and polyurethanes. The total content of polyester, that is, crystalline polyester and amorphous polyester is not particularly limited, but from the viewpoint of low-temperature fixability of the toner, it is preferably 95% by weight or more, more preferably 99% by weight or more in the binder resin. preferable.

  The toner of the present invention is obtained by a production method including a step [step (1)] of holding the toner composition containing the binder resin at a specific temperature, and the method includes the step (1). There is no particular limitation as long as it does.

  In the present invention, the toner composition containing the binder resin is obtained according to a known method such as a melt-kneading method or a wet method. Specifically, in the melt-kneading method, the binder resin and, if necessary, a toner material containing a colorant and the like are mixed, melt-kneaded, and appropriately pulverized, classified, and surface-treated. At this time, a melt-kneaded product obtained by melt-kneading may be used as a toner composition, a pulverized product obtained by pulverizing a melt-kneaded product, a classified product obtained by classifying the pulverized product, or a classified product thereof. A surface-treated product obtained by surface-treating may be used as a toner composition. In the wet method, toner particles obtained by forming the toner raw material into particles in a medium such as an aqueous medium and drying can be used as a toner composition. As the wet method, an emulsion aggregation method that enables high image quality by sharpening the particle size distribution and rounding the shape is preferable. In the emulsion aggregation method, the toner raw material is emulsified in a medium such as an aqueous medium to prepare emulsion particles, and the emulsion particles are aggregated and united to form particles. Therefore, in the present invention, the toner composition is distinguished from a state in which crystalline polyester and amorphous polyester contained as polyester are simply mixed without melting.

  Hereinafter, a method for obtaining a toner composition by melt kneading will be described. The melt-kneading method includes a melt-kneading step (melt-kneading step), a pulverizing step (pulverizing step), a classification step (classifying step), and a step of surface treatment with an external additive (surface treatment step). Is preferred. In the present invention, when the melt-kneaded product obtained in the melt-kneading step is used as a toner composition, the melt-kneaded product is subjected to the step (1), followed by a pulverization step, a classification step, and a surface treatment step. In the case where the pulverized product obtained in the pulverization step is used as the toner composition, the pulverized product may be subjected to the step (1) and then subjected to the classification step and the surface treatment step. When the classified product obtained in the classification step is used as a toner composition, the surface treatment product obtained in the surface treatment step may be performed after the classified product is subjected to the step (1). When the toner composition is used, the surface-treated product can be subjected to step (1).

  In the melt-kneading step, a toner raw material containing a binder resin containing the polyester is melt-kneaded.

  In addition to the above-mentioned polyester, toner raw materials include colorants, mold release agents, charge control agents, magnetic powders, conductivity modifiers, extender pigments, reinforcing fillers such as fibrous substances, antioxidants, anti-aging agents, flow And additives such as a property improver and a cleaning property improver.

  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, Isoindoline, Disazo Yellow and the like can be used alone or in admixture of two or more. Any of black toner, color toner, and 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.

  As release agents, natural waxes such as polypropylene wax, polyethylene wax, synthetic wax such as Fischer Tropu, coal wax such as montan wax, petroleum wax such as paraffin wax, wax such as alcohol wax, carnauba wax, rice wax, etc. An ester wax may be mentioned, and these waxes may be used alone or in admixture of two or more. The content of the release agent is preferably 1 to 20 parts by weight, more preferably 1 to 10 parts by weight and further 1 to 5 parts by weight with respect to 100 parts by weight of the binder resin from the viewpoint of toner fixing properties. preferable.

  The charge control agent may be either a positively chargeable charge control agent or a negatively chargeable charge control agent, and these may be used in combination. Examples of the positively chargeable charge control agent include digrosine dyes, triphenylmethane dyes containing tertiary amines as side chains, quaternary ammonium salt compounds, polyamine resins, and imidazole derivatives. Examples of the negatively chargeable charge control agent include metal-containing azo dyes, copper phthalocyanine dyes, metal complexes of alkyl derivatives of salicylic acid, and boron complexes of benzyl acid. The content of the charge control agent is preferably 0.1 to 5.0 parts by weight and more preferably 0.2 to 4.0 parts by weight with respect to 100 parts by weight of the binder resin.

  The method of melt kneading is not particularly limited. For example, a toner material such as a binder resin containing polyester is mixed with a mixer such as a Henschel mixer, and then a closed kneader, a single or twin screw extruder, an open It can be melt-kneaded with a roll-type kneader or the like.

  From the viewpoint of improving the dispersibility of the crystalline polyester, the temperature at the time of melt kneading is preferably Tm + 5 (° C.) or more, more preferably Tm (5 ° C.) or more, assuming that the maximum endothermic temperature in DSC measurement of the crystalline polyester is Tm (° C.). Is preferably Tm + 10 (° C.) or higher, more preferably Tm + 20 (° C.) or higher, and Tm + 100 (° C.) or lower. The temperature refers to a temperature at which the temperature of the melt-kneaded product (also referred to as a toner composition) falls within the above temperature range, and Tm is substantially the same as the highest endothermic peak temperature in the DSC measurement of the toner composition. Temperature.

  When the kneading machine is melt kneaded, the rotational speed of the kneading machine increases the dispersibility of the crystalline polyester and the crystals in the toner become smaller (that is, T1-T2 (° C.) becomes larger). It is considered that the dispersibility of the conductive polyester decreases and the crystals in the toner increase (that is, T1-T2 (° C.) decreases). For this reason, in the present invention, from the viewpoint of satisfying the relationship of the above formula (i), it is preferable to adjust the rotational speed of the kneader during melt kneading. Specifically, the rotational speed of the kneading machine at the time of melt-kneading is such that when T1-T2 (° C.) is less than 2.0, in order to reduce the crystals in the toner (that is, T1-T2 (° C.) Therefore, the rotation speed of the kneading machine for melting and kneading that is set in the case of producing a toner having T1-T2 (° C.) of less than 2.0 may be set, and T1-T2 (° C.) may be increased. In the case of exceeding 9.0, in order to increase the crystal in the toner (that is, in order to reduce T1-T2 (° C.)), it was set in the case of producing a toner having T1-T2 (° C.) exceeding 9.0. What is necessary is just to make it lower than the rotation speed of the kneading machine of melt-kneading.

  Further, it is considered that the size of crystals in the toner increases when the content of the crystalline polyester is large and decreases when the content is small. However, in the present invention, it is possible to adjust the size of crystals in the toner obtained by adjusting the particle size of the polyester used for melt-kneading in accordance with the content of the crystalline polyester. There was found. Therefore, in the present invention, from the viewpoint of satisfying the relationship of the above formula (i), the melt-kneading step is performed after adjusting the particle diameter by pre-grinding (preliminary grinding) the polyester to be subjected to the melt-kneading step. Is preferred. Specifically, when the particle size of the crystalline polyester is 3 to 5 mm, the crystalline polyester and the amorphous polyester are in a weight ratio of 10/90 to 30/70 (crystalline polyester / amorphous polyester). When the particle diameter is 1 to 2 mm, the weight ratio is 20/80 to 30/70, and when the particle diameter is 20 μm, the weight ratio is 20/80 to 40/60. It is possible to contain. In addition, it is preferable that the particle diameter of the amorphous polyester used together with the crystalline polyester which has the said particle diameter is 0.5-5 mm. In the present specification, polyester having a particle size of 5 mm is a polyester having a particle size of 70% by weight or more of particles that pass through a sieve having an opening of 5 mm in all particles but does not pass through a sieve having an opening of 4 mm. 3mm polyester is a polyester in which particles that pass through a sieve with a mesh opening of 3mm but do not pass through a sieve with a mesh opening of 2mm are 70% by weight or more, and a polyester with a particle diameter of 2mm. Polyester having 70% by weight or more of particles that pass through a 2mm sieve but not through a 1mm sieve in all particles. Polyester with a particle size of 1mm is 1mm in all grains. Means a polyester having a particle diameter of less than 70% by weight but not passing through a sieve having an opening of 0.1 mm, and a polyester having a particle diameter of less than 1 mm, for example, 20 μm, has an average particle diameter of Implementation described later It means a polyester which is measured by the method described in.

  There are no particular limitations on the preliminary pulverization method. For example, a pulverization method using an atomizer, a rotoplex, or the like suitably used for coarse pulverization, a jet mill, a collision plate mill, or a rotary mechanical mill suitably used for fine pulverization. And the like.

  The maximum endothermic peak temperature in DSC measurement of the obtained melt-kneaded product is preferably 80 to 125 ° C., more preferably 90 to 120 ° C., from the viewpoints of toner fixability, heat resistant storage stability and durability. In the present specification, the maximum peak temperature of endotherm is measured by the method described in Examples described later.

  In the pulverization step, from the viewpoint of production efficiency, it is preferable to pulverize the object to be pulverized after cooling to a pulverizable hardness before pulverization.

  The pulverization of the material to be pulverized may be performed once or divided into a plurality of times, but from the viewpoint of pulverization efficiency and production efficiency, the pulverization step preferably includes a coarse pulverization step and a fine pulverization step. It is preferable to coarsely pulverize the particle size in advance until the maximum diameter is preferably 3 mm or less, more preferably 2 mm or less, and then finely pulverize the obtained coarsely pulverized product in consideration of the target toner particle size. Here, the maximum diameter of 3 mm or less means that all toner particles pass through a sieve having an opening of 3 mm. Similarly, the maximum diameter of 2 mm or less means that all toner particles pass through a sieve having an opening of 2 mm. When the pulverized product is used as a toner composition, the pulverized product obtained by either the coarse pulverization step or the fine pulverization step may be used as the toner composition, but from the viewpoint of toner productivity (that is, pulverization property). Therefore, it is preferable to use the pulverized product obtained in the coarse pulverization step as a toner composition for the step (1). In this case, the retentate obtained in the step (1) may be used for the fine pulverization step and the classification step. Good. The obtained pulverized product also includes a pulverized product obtained by subjecting the pulverized product obtained by the pulverization step to a surface treatment with an external additive or the like.

  The pulverizer used in the pulverization step is not particularly limited. For example, as a pulverizer suitably used for coarse pulverization, an atomizer, a rotoplex, etc., as a pulverizer suitably used for fine pulverization, a jet mill, a collision Examples thereof include a plate mill and a rotary machine mill.

  In the classification step, the pulverized product obtained in the pulverization step is classified, and the classification method is not particularly limited, and a known method can be used.

  In the surface treatment step, the classified product obtained in the classification step is subjected to surface treatment with an external additive or the like, but the surface treatment method is not particularly limited, and a known method can be used.

  The content of the external additive is preferably 0.01 to 10 parts by weight and more preferably 0.1 to 5 parts by weight with respect to 100 parts by weight of the additive before the addition of the external additive.

  When a pulverized product, classified product or surface-treated product is used as a toner composition, the maximum endothermic peak temperature in the DSC measurement of the toner composition is in the same range as the temperature of the melt-kneaded product obtained by the melt-kneading step. It preferably has a temperature, preferably 80 to 125 ° C, more preferably 90 to 120 ° C.

  Next, the toner composition is subjected to step (1). From the viewpoint of toner productivity, fixability, and the like, the toner composition was obtained by a melt-kneaded product obtained by a melt-kneading step or a pulverizing step. The pulverized product is preferably subjected to step (1).

  In step (1), the toner composition is held at a specific temperature. The holding temperature is preferably 80 ° C. or less, more preferably 75 ° C. or less, further preferably 70 ° C. or less, further preferably 60 ° C. or less, and further preferably 55 ° C. or less from the viewpoint of low-temperature fixability of the toner. Further, from the viewpoint of heat resistant storage stability of the toner, it is preferably 40 ° C. or higher, more preferably 45 ° C. or higher, and further preferably 48 ° C. or higher. Therefore, in the step (1), the toner composition is preferably maintained at 40 to 80 ° C, more preferably 45 to 75 ° C, and further preferably 45 to 70 ° C. From the viewpoint of low-temperature fixability of the toner, it is preferable that the holding temperature does not exceed the upper limit of the temperature range during holding.

  The holding time at the holding temperature is preferably 1 to 100 hours, more preferably 12 to 80 hours, and still more preferably 24 to 72 hours, from the viewpoint of heat resistant storage stability of the toner.

  The step (1) may further include another holding step in addition to the holding step. The other holding step is desirably a step of holding at a temperature of 50 to 85 ° C. different from the holding temperature from the viewpoint of heat-resistant storage stability of the toner.

Thus, a retained toner can be obtained. The volume-median particle size (D ₅₀ ) of the toner obtained according to the present invention is preferably 3 to 15 μm, more preferably 4 to 10 μm, and even more preferably 5 to 9 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.

  The toner obtained by the present invention can be used alone as a one-component developer, or mixed with a carrier and used as a two-component developer.

[Softening point of resin]
Using a flow tester (Shimadzu Corporation, CFT-500D), while heating a 1g sample at a heating rate of 6 ° C / min, a plunger with a load of 1.96MPa was applied and extruded from a nozzle with a diameter of 1mm and a length of 1mm. . Plot the plunger drop amount of the flow tester against the temperature, and let the softening point be the temperature at which half of the sample flows out.

[Acid value of the resin]
Measured according to the method of JIS K0070. However, only the measurement solvent was changed from the mixed solvent of ethanol and ether specified in JIS K0070 to the mixed solvent of acetone and toluene (acetone: toluene = 1: 1 (volume ratio)).

[Melting point of resin (maximum endothermic peak temperature)]
Using a differential scanning calorimeter (manufactured by TA Instruments Japan Co., Ltd., Q-100), the sample cooled from room temperature to 0 ° C at a temperature lowering rate of 10 ° C / min is left still for 1 minute, and then the temperature is raised Measure up to 150 ° C at a rate of 10 ° C / min. Among the observed endothermic peaks, the temperature at the highest temperature is defined as the highest endothermic peak temperature, and if the highest peak temperature is within 20 ° C. of the softening point, the melting point (first melting point) is determined. A peak observed at a temperature lower than the melting point represented by the maximum peak temperature and a difference within 50 ° C. from the melting point is also regarded as a melting point (second melting point).

[Glass transition point of resin]
Using a differential scanning calorimeter (manufactured by TA Instruments Japan Co., Ltd., Q-100), the sample cooled from room temperature to 0 ° C at a temperature lowering rate of 10 ° C / min is left still for 1 minute, and then the temperature is raised Measure up to 150 ° C at a rate of 10 ° C / min. Among the observed endothermic peaks, when the maximum peak temperature is above the softening point and 20 ° C, the maximum slope from the peak extension to the peak apex is below the maximum endotherm peak temperature. Is the temperature at the intersection with the tangent line. Otherwise, among the observed endothermic peaks, an extension of the baseline below the peak observed below 50 ° C. below the melting point represented by the highest endothermic peak temperature, and the peak The temperature at the point of intersection with the tangent indicating the maximum slope from the rising part to the peak apex is read as the glass transition point.

(Resin particle size (less than 1mm))
In the present specification, the particle diameter of the resin means the particle diameter of the resin at which the cumulative volume frequency calculated by the volume fraction is 50% calculated from the smaller particle diameter.
Measuring instrument: Coulter Multisizer II (Beckman Coulter, Inc.)
Aperture diameter: 100μm
Analysis software: Coulter Multisizer AccuComp version 1.19 (Beckman Coulter)
Electrolyte: Isoton II (Beckman Coulter)
Dispersion: Emulgen 109P (manufactured by Kao Corporation, polyoxyethylene lauryl ether, HLB: 13.6) 5% by weight Electrolyte dispersion condition: 10 mg of measurement sample was added to 5 mL of dispersion, and dispersed for 1 minute with an ultrasonic disperser. Thereafter, 25 mL of an electrolytic solution is added, and further dispersed with an ultrasonic disperser for 1 minute.
Measurement conditions: The dispersion is added to 100 mL of the electrolytic solution so that the particle size of 30,000 toner particles can be measured in 20 seconds, and 30,000 particles are measured. Determine the median particle size (D ₅₀ ).

[Maximum endothermic peak temperature in DSC measurement of toner]
T1 (° C): Using a differential scanning calorimeter (manufactured by TA Instruments Japan, Q-100), using indium as a standard sample, calibrating the device at a heating rate of 10 ° C / min ( After executing the calibration program, the sample cooled from room temperature to 0 ° C at a temperature drop rate of 10 ° C / min is allowed to stand still for 1 minute, and then measured from 0 ° C to 150 ° C at a temperature rise rate of 10 ° C / min. In the present invention, the above calibration (calibration program) is always performed when measuring T1 (° C.).
T2 (° C): Using a differential scanning calorimeter (manufactured by TA Instruments Japan, Q-100), using indium as a standard sample, calibrate the device at a heating rate of 100 ° C / min ( After executing the calibration program, the sample cooled from room temperature to 0 ° C at a temperature drop rate of 10 ° C / min is allowed to stand still for 1 minute, and then measured from 0 ° C to 150 ° C at a temperature increase rate of 100 ° C / min. In the present invention, the above calibration (calibration program) is always performed when measuring T2 (° C.).

[Peak calorific value of endotherm in DSC measurement of toner]
Q2 (J / g): The endothermic amount represented by the area surrounded by the endothermic peak and the straight line connecting the baseline end before the peak of the maximum endothermic peak temperature (T2 (° C)) and the baseline end after the peak of the endothermic peak. This is a value obtained by dividing the sample weight by the sample weight (mJ) per unit of sample (mg), and is automatically calculated by the calorimeter.
Q3 (J / g): The sample cooled from room temperature to 0 ° C at a temperature drop rate of 10 ° C / min is allowed to stand still for 1 minute, then heated up to 150 ° C at a temperature rise rate of 10 ° C / min, and then the temperature drop rate The sample cooled to 0 ° C at 100 ° C / min is allowed to stand still for 1 minute, and then measured from 0 ° C to 150 ° C at a rate of temperature increase of 100 ° C / min. At that time, the endothermic amount indicated by the area surrounded by the endothermic peak and the straight line connecting the baseline end before the peak of the endothermic peak temperature observed at T2 ± 1 (° C) and the baseline end after the peak of the endothermic peak. It is obtained by dividing by the sample weight.

[Volume-median particle size of toner (D ₅₀ )]
In this specification, the volume-median particle size (D ₅₀ ) of the toner means the particle size of the toner in which the cumulative volume frequency calculated by the volume fraction is 50% calculated from the smaller particle size.
Measuring instrument: Coulter Multisizer II (Beckman Coulter, Inc.)
Aperture diameter: 50μm
Analysis software: Coulter Multisizer AccuComp version 1.19 (Beckman Coulter)
Electrolyte: Isoton II (Beckman Coulter)
Dispersion: Emulgen 109P (manufactured by Kao Corporation, polyoxyethylene lauryl ether, HLB: 13.6) 5% by weight Electrolyte dispersion condition: 10 mg of measurement sample was added to 5 mL of dispersion, and dispersed for 1 minute with an ultrasonic disperser. Thereafter, 25 mL of an electrolytic solution is added, and further dispersed with an ultrasonic disperser for 1 minute.
Measurement conditions: The dispersion is added to 100 mL of the electrolytic solution so that the particle size of 30,000 toner particles can be measured in 20 seconds, and 30,000 particles are measured. Determine the median particle size (D ₅₀ ).

Production Example 1 of Crystalline Polyester
Raw material monomers shown in Table 1, 8 g of tin (II) octylate (0.5 parts by weight based on 100 parts by weight of the total amount of alcohol and carboxylic acid components) and 1 g of tertiary butyl catechol (TBC) (of alcohol and carboxylic acid components) (0.05 parts by weight with respect to 100 parts by weight in total) was 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. The temperature was raised to 200 ° C. and reacted for 1 hour. Furthermore, it was made to react at 8.3 kPa for 3 hours, and resin a and b were obtained.

Production Example 2 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 inlet tube, dehydration tube, stirrer and thermocouple, and reacted at 200 ° C until no terephthalic acid particles were observed. , 8.3 kPa for 3 hours to obtain a resin c.

Production Example 1 of Amorphous Polyester
A reflux condenser in which raw material monomers other than trimellitic anhydride shown in Table 1 and tin (II) octylate 8 g (0.5 parts by weight with respect to 100 parts by weight of the total amount of alcohol component and carboxylic acid component) were passed through cold water at room temperature. In a 5-liter four-necked flask equipped with a distillation tube, nitrogen introduction tube, dehydration tube, stirrer, and thermocouple with 98 ° C warm water at the top, and at 230 ° C under a nitrogen atmosphere The reaction was allowed to take 8 hours. Further, trimellitic anhydride shown in Table 1 was added at 210 ° C. and reacted at normal pressure (101.3 kPa) for 1 hour, and then reacted at 40 kPa until the desired softening point was reached to obtain Resin A. It was.

Production Example 2 of Amorphous Polyester
Raw material monomers other than trimellitic anhydride shown in Table 1, 10 g of tin (II) octylate (0.5 parts by weight with respect to 100 parts by weight of the total amount of alcohol component and carboxylic acid component) and 1 g of tertiary butylcatechol (TBC) (alcohol) 0.05 parts by weight with respect to 100 parts by weight of the total amount of components and carboxylic acid components) is placed in a 5-liter four-necked flask equipped with a nitrogen inlet tube, a dehydrating tube, a stirrer, and a thermocouple. And then reacted at 8.3 kPa for 1 hour. Further, trimellitic anhydride shown in Table 1 was added and reacted at normal pressure (101.3 kPa) for 1 hour, and then reacted at 40 kPa until the desired softening point was reached, to obtain Resin B.

Production Example 1 of Toner Composition
Henschel mixer containing binder resin, release agent, 4.0 parts by weight of carbon black “Regal 330” (Cabot) and 0.5 parts by weight of charge control agent “T-77” (Hodogaya Chemical) shown in Table 2. Then, toner compositions 1 to 15 (S1 to S15) were produced by the following melt-kneading process. Each binder resin is pre-pulverized by attaching a 3mm mesh (aperture: 3mm) or 1mm mesh (aperture: 1mm) screen to the rotoplex, or I-2 type crusher (Nippon Pneumatic Co., Ltd.) Used).

[Melt-kneading process]
A co-rotating twin screw extruder (Ikegai Iron Works Co., Ltd., PCM-30-30) having a total length of 1560 mm, a screw diameter of 42 mm, and a barrel inner diameter of 43 mm was used. The barrel set temperature was 90 ° C. (kneaded temperature: 120 to 140 ° C.), the mixture feed rate was 10 kg / hour, the average residence time was about 18 seconds, and the screw rotation speed was as shown in Table 2.

Examples 1 to 12 and Comparative Examples 1 to 7 (Examples 6, 8, 10, and 11 are reference examples)
Using the toner compositions shown in Table 3, toners of Examples 1 to 12 and Comparative Examples 1 to 7 were manufactured by the following steps.

[Coarse grinding process]
The toner composition was rolled with a cooling roll, cooled to 20 ° C. or lower, and then coarsely pulverized by attaching a 3 mm mesh (aperture: 3 mm) screen to the funnel plex.

[Holding process]
The coarsely pulverized toner composition was held at the temperature and time shown in Table 3 using an oven.

[Fine grinding and classification process]
The obtained retentate was pulverized with an I-2 type pulverizer (manufactured by Nippon Pneumatic Co., Ltd.) and classified to obtain toner particles (classified product) having a volume-median particle size (D ₅₀ ) of 8.5 μm.

[Surface treatment process]
To 100 parts by weight of the obtained toner particles (classified product), 0.65 parts by weight of hydrophobic silica “TS-530” (manufactured by Cabot) is added as an external additive, and mixed with a Henschel mixer, to thereby add toner. Obtained.

Test Example 1 [low temperature fixability]
The toner of each example and comparative example is mounted on a copier “AR-505” (manufactured by Sharp) and adjusted so that the toner amount is 0.5 mg / cm ² , and then the image is taken out before fixing. An unfixed image was obtained. 90 ° C using the fixing machine (fixing speed: 250 mm / sec), which was modified so that the fixing machine of the copier "AR-505" (manufactured by Sharp) can be fixed off-line. The temperature was gradually increased from 5 ° C. to 240 ° C., and a fixed image was obtained. The image fixed at each temperature is rubbed 5 times with a sand eraser with a bottom of 15mm x 7.5mm under a 500g load, and the reflection density meter "RD-915" (manufactured by Macbeth) is used to measure the optical reflection density before and after rubbing. The temperature of the fixing roll in which the ratio between the two (after rubbing / before rubbing) first exceeded 70% was defined as the minimum fixing temperature, and the low-temperature fixing property was evaluated according to the following evaluation criteria. The results are shown in Table 2. The paper used for the fixing test is a thick paper “CopyBond SF-70NA” (75 g / m ² ) manufactured by Sharp Corporation, and the lower the minimum fixing temperature, the better the low-temperature fixing property.

[Evaluation criteria for low-temperature fixability]
A: Minimum fixing temperature is less than 140 ° C B: Minimum fixing temperature is 140 ° C or more and less than 160 ° C C: Minimum fixing temperature is 160 ° C or more

Test Example 2 [Heat resistant storage stability]
In 20 mL of polybin, 4 g of the toners of the examples and comparative examples were placed and left in an environment of 50 ° C. for 48 hours. After standing, the aggregation degree was measured with a powder tester (manufactured by Hosokawa Micron Corporation) by the following method, and the heat resistant storage stability was evaluated according to the following criteria. In addition, the one where a cohesion degree is smaller shows that it is favorable heat-resistant storage stability.

<Measurement of cohesion>
Place three different sieves in the order of 250μm on the upper stage, 149μm on the middle stage, and 74μm on the lower stage on the powder tester's shaking table, put 4g of toner on it, give vibration, and measure the weight of toner remaining on each sieve To do. The measured toner weight is applied to the following equation and calculated to obtain the degree of aggregation [%].
Aggregation degree [%] = a + b + c
a = (weight of residual toner on upper stage) / 4 [g] × 100
b = (middle stage residual toner weight) / 4 [g] × 100 × (3/5)
c = (lower stage residual toner weight) / 4 [g] × 100 × (1/5)

[Evaluation criteria for heat-resistant storage stability]
A: The aggregation degree is less than 20, and the heat resistant storage stability is good.
B: The aggregation degree is 20 or more and less than 60, and the heat resistant storage stability is good.
C: The aggregation degree is 60 or more and less than 80, and the heat-resistant storage stability is slightly poor.
D: The aggregation degree is 80 or more, and the heat resistant storage stability is poor.

  From the above results, it can be seen that the toners of Examples 1 to 12 are excellent in low-temperature fixability and heat-resistant storage stability as compared with the toners of Comparative Examples 1 to 7. In particular, as in Example 1, when T1-T2 (° C.) is 5.5 ° C., the balance between the low-temperature fixability and the heat-resistant storage stability is considered to be excellent. This is presumably because the crystals are finely dispersed at the time of melting and retain the filler effect of the crystals. On the other hand, Comparative Example 1 has large crystals and the fixability deteriorates. Further, in Comparative Example 2, the microcrystalline filler effect is weak and the heat resistant storage stability is deteriorated. In Comparative Example 3, since the content of the crystalline polyester having a small particle diameter is large, the filler effect of the crystal is weak and the heat resistant storage stability is deteriorated. On the contrary, in Comparative Example 4, the content of the crystalline polyester having a large particle size is small, so that the low-temperature fixability is deteriorated. In Comparative Example 5, since the compatibility between the crystalline polyester and the amorphous polyester is lower than S1, the low-temperature fixability is deteriorated. In Comparative Example 6, since the kneading strength is too strong, the heat-resistant storage stability is deteriorated due to the refinement of crystals and the weaker filler effect. On the contrary, in Comparative Example 7, the kneading strength is too weak, so that the crystals cause poor dispersion and the low-temperature fixability deteriorates.

  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 (4)

Contains a binder resin including polyester, and has the formula (i):
2.0 ≤ T1-T2 ≤ 9.0 (i)
[In the formula, T1 indicates the maximum endothermic peak temperature (° C) in differential scanning calorimetry under the condition (A), and T2 indicates the maximum endothermic temperature (° C) in differential scanning calorimetry under the condition (B)]
And formula (ii):
Q3 / Q2 × 100 ≦ 30 (ii)
[In formula, Q2 is the maximum peak calorie (J / g) of endothermic measurement in differential scanning calorimetry under condition (B), and Q3 is the endotherm observed at T2 ± 1 (° C) in differential scanning calorimetry under condition (C). (Shows peak heat value (J / g))
To satisfy the relationship, there is provided a toner for electrophotography,
The polyester comprises an amorphous polyester obtained by polycondensing a crystalline polyester and an alcohol component containing a C 2-8 aliphatic diol and a carboxylic acid component, in the binder resin, An electrophotographic toner in which the content of the crystalline polyester is 5 to 25% by weight and the content of the amorphous polyester is 70 to 95% by weight .
Condition (A): Measurement condition from 0 ° C to 150 ° C at a temperature increase rate of 10 ° C / min (B): Measurement condition from 0 ° C to 150 ° C at a temperature increase rate of 100 ° C / min (C): Temperature increase rate of 10 ° C After heating from 0 ° C to 150 ° C at / min, cooling from 150 ° C to 0 ° C at a rate of temperature drop of 100 ° C / min, and further measuring from 0 ° C to 150 ° C at a rate of temperature rise of 100 ° C / min The crystalline polyester polycondenses an alcohol component containing 70 mol% or more of an aliphatic diol having 2 to 8 carbon atoms and a carboxylic acid component containing 70 mol% or more of an aliphatic dicarboxylic acid compound having 2 to 8 carbon atoms. The toner for electrophotography according to claim 1, which is a crystalline polyester obtained in the above manner. The toner for electrophotography according to claim 1 or 2 , wherein the alcohol component of the amorphous polyester further contains an aliphatic diol having a branched hydrocarbon group. A method for producing an electrophotographic toner according to any one of claims 1 to 3, comprising a step of melt-kneading a toner raw material containing a binder resin containing polyester, a step of pulverizing the obtained melt-kneaded product, and A method for producing an electrophotographic toner, comprising a step of maintaining the pulverized product at 40 to 80 ° C. [Step (1)].