JP2012063471A - Electrophotographic toner, developer using toner, image forming apparatus, image forming method, and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide toner comprising resin particles excellent in low temperature fixing characteristics, heat-resistant storage properties and chargeability even when polylactic acid is used, and to provide an image forming apparatus, an image forming method and a process cartridge.SOLUTION: The electrophotographic toner comprises resin particles (C) having such a structure that resin particles (A) containing a first resin (a) or a coating film (P) containing the resin (a) are adhered to the surface of a resin particle (B) containing a second resin (b). The resin (b) is linear polyester prepared by extending an oligomer having a polyhydroxycarboxylic acid skeleton obtained from a diol having an aromatic ring and a hydroxycarboxylic acid.

Description

  The present invention relates to an electrophotographic toner used for electrophotographic image formation, a developer using the toner, an image forming apparatus, an image forming method, and a process cartridge.

Conventionally, in an electrophotographic image forming apparatus, an electrostatic recording apparatus, or the like, an electrical or magnetic latent image is visualized with toner. For example, in electrophotography, an electrostatic charge image (latent image) is formed on a photoreceptor, and then the latent image is developed using toner to form a toner image. The toner image is usually transferred onto a recording medium such as paper and then fixed by a method such as heating.
The toner used for developing an electrostatic image is generally colored particles containing a colorant, a charge control agent, etc. in a binder resin, and the production method is roughly divided into a pulverization method and a suspension polymerization method. There is.

  In the pulverization method, a toner is produced by pulverizing and classifying a toner composition obtained by uniformly dispersing a colorant, a charge control agent, an offset preventing agent and the like in a thermoplastic resin by melt mixing. According to this pulverization method, a toner having some excellent characteristics can be produced, but there is a limitation in the selection of materials. For example, a toner composition obtained by melt mixing must be capable of being pulverized and classified by an economically usable apparatus. From this demand, the toner composition obtained by melt mixing must be made sufficiently brittle. When pulverizing such a toner composition, particles having a wide particle size distribution are likely to be formed. At this time, in order to obtain a copy image with good resolution and gradation, for example, fine powder having a particle size of 5 μm or less and coarse powder having a particle size of 20 μm or more must be removed by classification, yield. Is very low. In the pulverization method, it is difficult to uniformly disperse the colorant, the charge control agent and the like in the thermoplastic resin, and the obtained toner has an adverse effect on fluidity, developability, durability, image quality, and the like. There is a problem that arises.

  Therefore, in Patent Documents 1 and 2, a resin solution in which a resin synthesized in advance by a polymerization reaction is dissolved is used as a dispersion (auxiliary) agent such as a surfactant or a water-soluble resin, and a dispersion stabilizer such as inorganic fine particles and resin fine particles. There has been proposed a dissolved resin suspension method in which a toner is obtained by dispersing in an aqueous medium in the presence of water and removing the solvent by heating, decompression or the like. According to this dissolved resin suspension method, a uniform toner can be obtained without classification.

  In addition, in an electrophotographic image forming apparatus, in a fixing process by a contact heating method performed using a heating member such as a heat roller, releasability (hereinafter sometimes referred to as offset resistance) to the heating member is provided. Required. This offset resistance is solved by using a modified polyester resin in the dissolved resin suspension method (see Patent Document 3).

  By the way, most of the binder resin occupying 70% or more of the constituent components of the toner is made from petroleum resources. This is due to the problem of exhaustion of petroleum resources, large consumption of petroleum resources, and emission of carbon dioxide into the atmosphere. There are concerns about global warming. Therefore, if a plant-derived resin that grows by taking in carbon dioxide in the atmosphere is used as the binder resin, the resulting carbon dioxide will only circulate in the environment, which simultaneously raises the problem of global warming and the depletion of petroleum resources. Various toners using such plant-derived resins as binder resins have been proposed. For example, Patent Document 4 proposes using polylactic acid as a binder resin. However, when polylactic acid is used as it is as in this proposal, the concentration of the ester bond is higher than that of the polyester resin, so that the action as a thermoplastic resin is lowered during fixing. Further, since the toner becomes very hard, there is a problem that the grindability is poor and the productivity is inferior.

  Polylactic acid, which is widely available as a plant-derived resin, is synthesized by dehydration condensation of lactic acid or ring-opening polymerization of lactic acid cyclic lactide as described in Patent Documents 5 and 6. For this reason, when manufacturing a toner using polylactic acid, the dissolving resin suspension method like the said patent documents 1-3 can be used. However, since polylactic acid has high crystallinity only in the L-form or D-form, the solubility in an organic solvent is extremely low, and it is difficult to use the dissolved resin suspension method. For this reason, it is possible to improve the solubility to an organic solvent by mixing the L-form and D-form of polylactic acid to reduce crystallinity.

  On the other hand, polylactic acid is difficult to control the molecular weight and has ester bonds only through carbon atoms, so that it is difficult to achieve the physical properties necessary for the toner only with polylactic acid. On the other hand, it is conceivable to ensure the physical properties and thermal characteristics required for the toner by mixing polylactic acid and other resins as in the conventional methods. Since the compatibility and dispersibility with respect to a polyester resin and a styrene-acrylic copolymer, which are generally used for toner, are extremely poor, it is very difficult to produce a toner in this way.

  In addition, since the crystallization speed of polylactic acid is slow, it is difficult to control the crystalline state of polylactic acid in the toner produced using the dissolved resin suspension method, and the toner produced using the dissolved resin suspension method. May contain polylactic acid having high crystallinity and polylactic acid having low crystallinity. Therefore, there is a problem that the charge amount and the image density change over time due to the crystal growth of the portion having polylactic acid with low crystallinity over time.

  One of the problems with polylactic acid of L-form or D-form is that it has high crystallinity and does not melt at low temperatures. On the other hand, the above-mentioned solution for enabling low-temperature melting by racemization is low-temperature fixing. Although it is an effective means for conversion, it becomes a resin having a lower Tg than conventional petroleum-derived resins. Patent Document 7 proposes a method in which a racemic polylactic acid is used and a core shell is formed so that the toner has suitable fixing characteristics and heat-resistant storage stability. Another problem with polylactic acid is that the ester group concentration, which is hydrophilic, is high and the amount of charge is low and unstable, and it is considered that surface coating by shelling is also an effective means. However, in the case of conventional unmodified polylactic acid, because of its low Tg, if an insufficiently coated toner is present, toner aggregates are generated even in a relatively high temperature environment such as summer. . The above problem does not occur if all toner particles are sufficiently coated, but such an ideal toner can be produced in a laboratory environment where manufacturing conditions can be strictly controlled. It is fully conceivable that toner with insufficient coverage is generated under scale-up conditions on the premise of industrial mass production. In recent development of low-temperature fixing compatible toner, it has been known that when toner aggregates are generated, troubles may occur during development. Aggregates may be generated in the inside, and a solution using a method different from shelling together with shelling is desired.

  Therefore, a polylactic acid-containing toner and its related technology, which have excellent low-temperature fixing, heat-resistant storage stability, high charge amount and little change, have not yet been obtained, and further improvement and development are desired. It is.

  The present invention has been made in view of the above circumstances in the prior art. That is, even when polylactic acid is used, the present invention provides a toner, an image forming apparatus, an image forming method, and a process cartridge composed of resin particles having excellent low-temperature fixing characteristics, heat-resistant storage stability, and chargeability.

The problem is essentially due to the low Tg of the resin. As a means for solving the problem, modification of polylactic acid resin is considered as a direct method.
As a typical method considered as a means of resin modification,
(Method 1) Modification after resin synthesis (Method 2) Introduction of different materials during resin synthesis.

  There are two types of polylactic acid synthesis: lactide ring-opening polymerization and direct dehydration condensation from lactic acid monomers. From the viewpoint of physical properties, if the synthesized resin contains water, hydrolysis proceeds with long-term storage. The main reason for this is that the environmental stability of the charge amount is poor if the toner resin contains water, and that for synthesis reasons, it is difficult to synthesize high molecular weight polylactic acid by dehydration condensation. Lactide opening polymerization is generally used, and is preferred for the synthesis of toner resins.

As a modification of polylactic acid resin using lactide ring-opening polymerization, (Method 1) modification after resin synthesis is difficult. The resulting resin is a bulk solid mass, and in order to perform modification using a chemical reaction, it is necessary to perform dissolution in a solvent or pulverization sufficiently as a process, which is easy for industrial production processes. In addition, it is difficult to uniformly modify all the molecules of the resin.
Therefore, as a method for modifying polylactic acid as a resin for toner, (Method 2) introduction of different materials during resin synthesis is desirable.

If polylactic acid is not distinguished from L-form and D-form, it can be regarded as a homopolymer in which the same monomers are continuous. The following method can be considered as a method for introducing another monomer or a polymer composed of another monomer. (1) Block copolymer, (2) Graft copolymer, (3) Random copolymer.
Among the above, (1) and (2) are states in which a continuous portion of polylactic acid remains, and even if a resin having a higher Tg than that of polylactic acid, which is composed of another monomer, is introduced, The characteristic of Tg does not disappear due to the presence of lactic acid continuous sites. This is widely known as a general polymer property. The essential increase in Tg is achieved by introducing a monomer species that lowers the degree of polymerization of the lactic acid continuous site below the degree of polymerization (50 to 100 or more in repeating units) and expresses high Tg. It is necessary to eliminate the Tg property inherent to lactic acid to produce a resin in the form of random copolymer (3).

  As a result of intensive studies by the present inventors, it was difficult to obtain as a monomer component extracted from plants, and attention was paid to an aromatic ring contained in a relatively large amount in petroleum polyesters, and (I) both ends of the aromatic ring were diols. An oligomer obtained by polymerizing lactic acid using the monomer obtained as an initiator, and (II) the terminal diol portion of the obtained oligomer is extended with an extender, and the resulting linear polyester is used in the toner. Thus, the inventors have invented a toner having the desired thermophysical properties.

However, in this case as well, it is possible to solve the previous problem that polylactic acid has a low Tg, but the low chargeability due to the high ester group concentration of polylactic acid is related to the ester group part of lactic acid. Since hydrophilicity is a problem, it is not a complete solution.
However, the use of the above-mentioned resin is a method that can be used in combination with shelling by surface resin particle coating, which has been studied in the past. In the case of a resin having a low Tg, there was a problem that toner agglomerates were generated if even a small amount of particles with insufficient shelling were present. Even when toner that is insufficiently shelled is generated by the shelling, the high Tg of the resin in the core part does not generate an aggregate, and the shell part suppresses the hydrophilicity of the core part. Thus, the present inventors have invented a toner that solves the above problem.

That is, the present invention is as follows.
(1) The surface of the resin particle (B) containing the second resin (b), wherein the resin particle (A) containing the first resin (a) or the coating (P) containing the resin (a) A toner comprising resin particles (C) having a structure attached to the resin, wherein the resin (b) extends an oligomer having a polyhydroxycarboxylic acid skeleton obtained from a diol containing an aromatic ring and a hydroxycarboxylic acid. An electrophotographic toner, which is a linear polyester.
(2) The toner for electrophotography according to (1), wherein the linear polyester has a glass transition temperature of 60 ° C. or higher and 75 ° C. or lower.
(3) The toner for electrophotography according to (1) or (2), wherein the oligomer having the polyhydroxycarboxylic acid skeleton has a number average molecular weight of 2000 to 5000.
(4) The toner for electrophotography according to any one of (1) to (3), wherein the linear polyester has a number average molecular weight of 7,000 to 30,000.
(5) The electrophotographic toner according to any one of (1) to (4), wherein the total weight ratio of the aromatic ring-containing diol part to the linear polyester is 10 wt% or more and 50 wt% or less. .
(6) The polyhydroxycarboxylic acid skeleton contains a polyhydroxycarboxylic acid skeleton composed of an optically active monomer, and the polyhydroxycarboxylic acid skeleton composed of the optically active monomer has an optical purity X (%) = | X (L isomer) -X (D isomer) | [where X (L isomer) is the L isomer ratio (mol%) in terms of optically active monomer, and X (D isomer) is the D isomer ratio in terms of optically active monomer ( The toner for electrophotography according to any one of (1) to (5) above, wherein the toner represents 80% or less.
(7) The electrophotographic toner according to any one of (1) to (6), wherein the diol containing an aromatic ring is bis (2-hydroxyethyl) terephthalate (BHET).
(8) The electrophotographic toner according to any one of (1) to (7), wherein a diisocyanate compound is used as an extender when the oligomer having a polyhydroxycarboxylic acid skeleton is extended.
(9) The toner for electrophotography according to any one of (1) to (8), wherein the resin (a) is polyester.
(10) The toner for electrophotography according to any one of (1) to (9), wherein the toner contains a colorant.
(11) The toner for electrophotography according to any one of (1) to (10), wherein the toner contains a release agent.
(12) The electrophotographic toner according to any one of (1) to (11), wherein the toner contains a charge control agent.
(13) A developer using the electrophotographic toner according to any one of (1) to (12).
(14) An electrostatic latent image carrier, charging means for charging the surface of the electrostatic latent image carrier, and exposure means for exposing the charged electrostatic latent image carrier surface to form an electrostatic latent image Developing means for developing the electrostatic latent image with toner to form a visible image; transfer means for transferring the visible image to a recording medium; and fixing the transferred image transferred to the recording medium. An image forming apparatus having at least a fixing unit, wherein the toner is the electrophotographic toner according to any one of (1) to (12).
(15) A charging step for charging the surface of the electrostatic latent image carrier, an exposure step for exposing the charged electrostatic latent image carrier surface to form an electrostatic latent image, and the electrostatic latent image with toner. An image forming method comprising at least a developing step for developing a visible image by using the developing method, a transferring step for transferring the visible image to a recording medium, and a fixing step for fixing the transferred image transferred to the recording medium An image forming method, wherein the toner is the electrophotographic toner according to any one of (1) to (12).
(16) At least an electrostatic latent image carrier and development means for developing the electrostatic latent image formed on the electrostatic latent image carrier using toner to form a visible image, and forming an image A process cartridge which is detachable from an apparatus main body, wherein the toner is the electrophotographic toner according to any one of (1) to (12).

The toner of the present invention has the following effects.
A toner that is excellent in both low-temperature fixability and heat-resistant storage stability, has a large amount of charge, and has little change in charge amount over time.

It is a schematic sectional drawing of an example of the image forming apparatus of this invention. It is a schematic sectional drawing of an example of the process cartridge of this invention.

The present invention will be described in detail below.
(Resin b)
The resin particles (A) containing the first resin (a) or the coating (P) containing the resin (a) of the present invention is a surface of the resin particles (B) containing the second resin (b). In the resin particle (C) having a structure attached to the resin, the resin (b) is obtained by converting an oligomer (b1) containing a polyhydroxycarboxylic acid skeleton obtained from a diol containing an aromatic ring and a hydroxycarboxylic acid into an extender. It contains a linear polyester resin obtained by reacting together. In order to obtain a linear polyester, each of (b1) and the stretching agent needs to be bifunctional. When either one is trifunctional or more, the crosslinking reaction proceeds and a linear polyester cannot be obtained.
Linear polyesters are more suitable for toners in terms of solvent solubility and viscoelasticity than branched or network polyesters, and are advantageous in terms of ease of property control and manufacturability. is doing.

Random copolymerization is achieved by creating an oligomer obtained by polymerizing hydroxycarboxylic acid using a monomer obtained by diolation of both ends of the aromatic ring as an initiator, and extending the diol portion of both ends of the obtained oligomer using an extender. The linear polyester resin. By adopting such a structure, by introducing a monomer species which lowers the degree of polymerization of the hydroxycarboxylic acid continuous site from the degree of polymerization (50 to 100 or more in repeating units) and expresses high Tg. Further, it is possible to obtain a resin having a high Tg by eliminating the property of Tg inherent to polyhydroxycarboxylic acid.
In order to eliminate the property of Tg inherent to polyhydroxycarboxylic acid, the number average molecular weight of the oligomer is preferably 2000 to 5000. When the oligomer is, for example, Mn = 3000, considering that lactic acid is linked to both ends of the aromatic diol, on average, it repeats about 15 units on one side, and generally the properties of a polymer are expressed. Compared with the polymerization degree of 50 to 100, the Tg property of a resin composed of 100% polylactic acid does not appear. Synthesizing a short chain polylactic acid using a monomer component containing an aromatic ring as an initiator, followed by isocyanate extension is a two-step synthesis. This is a synthesis method in which it is difficult to produce a continuous part of the same monomer as compared with the above polymer synthesis, and a resin having such a configuration can realize stable thermophysical properties.

  The polyhydroxycarboxylic acid skeleton constituting (b1) has a skeleton obtained by polymerizing hydroxycarboxylic acid, and can be formed by a method of directly dehydrating condensation of hydroxycarboxylic acid or a method of ring-opening polymerization of a corresponding cyclic ester. In the case of dehydration condensation, water that cannot be dehydrated may remain in the solid block resin obtained in the synthesis word, and therefore, ring-opening polymerization of a cyclic ester is preferred as a synthesis as a toner resin.

  Examples of hydroxycarboxylic acids include aliphatic hydroxycarboxylic acids (such as glycolic acid, lactic acid, and hydroxybutyric acid), aromatic hydroxycarboxylic acids (such as salicylic acid, creosote acid, mandelic acid, burric acid, and syringic acid), or mixtures thereof. Corresponding cyclic esters include glycolide, lactide, γ-butyrolactone, 6-valerolactone and the like. Among these, from the viewpoint of the transparency and thermal characteristics of the resin particles (C), the monomer that forms the polyhydroxycarboxylic acid skeleton is preferably an aliphatic hydroxycarboxylic acid and a cyclic ester, more preferably 2 to 2 carbon atoms. 6 hydroxycarboxylic acids (including the corresponding cyclic esters), particularly preferably glycolic acid, lactic acid, glycolide, and lactide, and most preferably glycolic acid and lactic acid.

When the monomer that forms the polyhydroxycarboxylic acid skeleton is an optically active monomer such as lactic acid, the optical purity X (%) = | X (L isomer) −X (D isomer) | [where X (L Is a L-form ratio (%) in terms of optically active monomer, and X (D-form is a D-form ratio (%) in terms of optically active monomer)] is preferably 80% or less, more preferably 60% or less. Within this range, solvent solubility is improved.
Here, the method for measuring the optical purity X is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a polymer or toner having a polyester skeleton is treated with pure water, 1N sodium hydroxide and isopropyl alcohol. And then hydrolyzed by heating and stirring at 70 ° C. Subsequently, the solid content in the liquid is removed by filtration and neutralized by adding sulfuric acid to obtain an aqueous solution containing L- and / or D-lactic acid decomposed from the polyester resin. The aqueous solution was measured by a high performance liquid chromatograph (HPLC) using a chiral ligand exchange type column SUMICHILAR OA-5000 (manufactured by Sumika Chemical Analysis Co., Ltd.), and a peak area S (L ) And D-lactic acid-derived peak area S (D). The optical purity X can be determined from the peak area as follows.
X (L-form)% = 100 × S (L) / (S (L) + S (D))
X (D form)% = 100 × S (D) / (S (L) + S (D))
Optical purity X% = | X (L form) -X (D form) |
Of course, the L-form and D-form used in the raw materials are optical isomers, and the optical isomers have the same physical and chemical properties other than the optical characteristics. The reactivity is equal, and the component ratio of the monomer and the component ratio of the monomer in the polymer are the same.

When synthesizing an oligomer having a polyhydroxycarboxylic acid skeleton, as a reaction initiator, any conventionally known alcohol component can be used as long as it is an alcohol component that does not volatilize even when subjected to vacuum drying at 100 ° C. and 20 mmHg or less and polymerization heating at about 200 ° C. By using a diol component, a linear oligomer having hydroxyl groups at both ends can be obtained. In the present invention, a diol component described later is used as an initiator, Introduced into lactic acid skeleton. The diol component used is a diol having an aromatic ring, such as bis (2-hydroxyethyl) terephthalate (BHET), bis (2-hydroxypropyl) terephthalate (BHPT), bisphenols (bisphenol A, bisphenol F, bisphenol S, etc.) ) Alkylene oxide (the alkylene oxide is hereinafter abbreviated as AO, specific examples include ethylene oxide, propylene oxide, butylene oxide, etc.) and adducts thereof, and combinations thereof, preferably bis (2-hydroxy Ethyl) terephthalate (BHET) and bis (2-hydroxypropyl) terephthalate (BHPT), particularly preferably BHET.
The oligomer can be synthesized by a known method in the same manner as ordinary polyester synthesis, and the number average molecular weight of the oligomer can be adjusted by adjusting the amount of reaction initiator charged.

The diol component having an aromatic ring is added to improve the glass transition temperature of the linear polyester resin composition, and the content thereof is 10 wt% or more and 50 wt% or less in the linear polyester resin composition. Is preferred. If it is less than 10 wt%, the heat-resistant storage stability is deteriorated because the effect of increasing the Tg of the linear polyester of the present invention is not sufficiently obtained as compared with a linear resin composed of only polylactic acid. Sufficient low-temperature fixability, which is an advantage of using a polylactic acid skeleton, cannot be obtained.
The total weight ratio of the diol part in the linear polyester is basically the same as the weight ratio of the raw materials used at the time of synthesis. However, when the weight ratio is obtained from the resin after synthesis, 1H-NMR measurement is used. It can be determined from the monomer ratio calculated from the proton peak area of the polyhydroxycarboxylic acid moiety and the proton peak area of the aromatic ring moiety.

  In the present invention, the oligomer obtained from the above aromatic ring-containing diol and hydroxycarboxylic acid is polymerized with a stretching agent. As the extender, any compound having two functional groups having reactivity with a hydroxyl group can be used. Examples include isocyanate compounds, glycidyl compounds, carbodiimide compounds, vinyl compounds, and the like.

  Among them, the isocyanate compound is particularly effective because it generates a urethane bond by the reaction between the hydroxyl group and the isocyanate, and contributes to improving the rigidity of the molecular chain by the interaction between the urethane bonds. Specific examples of the isocyanate compound include conventionally known bifunctional isocyanate compounds such as isophorone diisocyanate, hexamethylene diisocyanate (abbreviation: HDI), lysine diisocyanate, xylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, and cyclohexane diisocyanate. Of these, isophorone diisocyanate (abbreviation: IPDI) is preferable from the viewpoint of reactivity and safety.

  The reaction conditions for increasing the molecular weight with an extender may be heating conditions below the boiling point of the solvent used. The amount of the extender is preferably 6 to 25 wt%, more preferably 10 to 20 wt%, based on the weight after synthesis. If the amount is less than 6 wt%, the extension may be insufficient and the desired physical properties may not be achieved. If the amount exceeds 25 wt%, the unused extender may remain in the resin and cause problems after toner preparation. .

The glass transition temperature of the resin (b) obtained by the present invention is preferably 60 ° C. or higher and 75 ° C. or lower. When the temperature is lower than 60 ° C, the storage stability is not sufficiently improved, and when the temperature exceeds 75 ° C, sufficient low-temperature fixability cannot be obtained.
The glass transition temperature can be measured as follows.
(Measurement of glass transition temperature (Tg))
Device: DSC (TA Instruments, Q2000)
What filled 5-10 mg of samples in the aluminum simple airtight bread | pan was used for the following measurement flows.
1st Heating: 30 ° C. to 220 ° C., 5 ° C./min. Hold for 1 minute after reaching 220 ° C. Cooling: Quench to −20 ° C. without temperature control, hold for 1 minute after reaching −20 ° C. 2nd Heating: −20 ° C. to 180 ° C., 5 ° C./min.
The glass transition temperature was evaluated by adopting the midpoint method in the 2nd Heating thermogram and reading the value.

  The number average molecular weight of the linear polyester obtained by the present invention is preferably 7000 or more and 30,000 or less. When the number average molecular weight exceeds 30,000, the minimum fixing temperature is deteriorated. When the number average molecular weight is less than 7,000, the maximum fixing temperature is deteriorated.

(Resin a)
The resin (a) may be any resin, and may be thermoplastic or thermosetting resin. For example, styrene-acrylic resin, vinyl resin, polyurethane resin, epoxy resin, polyester resin , Polyamide resin, polyimide resin, silicon resin, phenol resin, melamine resin, urea resin, aniline resin, ionomer resin, polycarbonate resin and the like. As the resin (a), two or more of the above resins may be used in combination. Among these, a vinyl resin, a polyester resin, a polyurethane resin, an epoxy resin and a combination thereof are preferable from the viewpoint that an aqueous dispersion of fine spherical resin particles is easily obtained, and preferably a styrene-acrylic resin or a polyester resin, More preferred is a polyester resin.

  The styrene-acrylic resin (including styrene-acrylic resin, styrene resin, and acrylic resin) is not particularly limited as long as it is composed of a styrene monomer and / or an acrylic monomer. Examples of the styrene monomer include styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, α-methyl styrene, p-ethyl styrene, 2,4-dimethyl styrene, pn-butyl styrene, p. -Tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, p-methoxy styrene, p-phenyl styrene P-chlorostyrene, 3,4-dichlorostyrene, and the like can be used. Examples of the acrylic monomer include methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, Stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methyl α-chloroacrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-methacrylate Octyl, dodecyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate α- methyl fatty monocarboxylic acid esters such as may be used.

The polyester-based resin is not particularly limited as long as it is composed of a polybasic acid and a polyhydric alcohol, and can be appropriately selected according to the purpose.
Examples of the aromatic dicarboxylic acid in the polybasic acid include terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, and biphenyldicarboxylic acid. Further, if necessary, a small amount of 5-sodium sulfoisophthalic acid or 5-hydroxyisophthalic acid can be used as long as the water resistance is not impaired. Examples of the aliphatic dicarboxylic acid include oxalic acid, (anhydrous) succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, hydrogenated dimer acid, and other saturated dicarboxylic acids, fumaric acid, (anhydrous) maleic acid, ( And unsaturated dicarboxylic acids such as itaconic acid anhydride, citraconic acid anhydride, and dimer acid. Examples of the alicyclic dicarboxylic acid include 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 2,5-norbornenedicarboxylic acid (anhydride), and tetrahydrophthalic acid (anhydrous anhydride). Etc.).

On the other hand, about a polyhydric alcohol component, C2-C10 aliphatic glycol, C6-C12 alicyclic glycol, ether bond containing glycol etc. are mentioned as glycol.
Examples of the aliphatic glycol having 2 to 10 carbon atoms include ethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 1,4-butanediol, 2-methyl-1,3-propanediol, 1 , 5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, 2-ethyl-2-butylpropanediol and the like.
Examples of the alicyclic glycol having 6 to 12 carbon atoms include 1,4-cyclohexanedimethanol.
Examples of the ether bond-containing glycol include diethylene glycol, triethylene glycol, dipropylene glycol, and glycols obtained by adding 1 to several moles of ethylene oxide or propylene oxide to two phenolic hydroxyl groups of bisphenols, for example, 2 , 2-bis (4-hydroxyethoxyphenyl) propane and the like. Polyethylene glycol, polypropylene glycol, and polytetramethylene glycol can also be used if necessary. However, since the ether structure reduces the water resistance and weather resistance of the polyester resin coating, the amount used is preferably 10% by mass or less, more preferably 5% by mass or less of the total polyhydric alcohol component.

The polyester-based resin can be synthesized by copolymerizing a tribasic or higher polybasic acid and / or a polyhydric alcohol as necessary.
Examples of the tribasic or higher polybasic acid include (anhydrous) trimellitic acid, (anhydrous) pyromellitic acid, (anhydrous) benzophenone tetracarboxylic acid, trimesic acid, ethylene glycol bis (anhydro trimellitate), glycerol tris (Anhydro trimellitate), 1,2,3,4-butanetetracarboxylic acid and the like.
Examples of the trifunctional or higher polyhydric alcohol include glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol.
The tri- or higher functional polybasic acid and / or polyhydric alcohol is copolymerized in the range of 10 mol% or less, preferably 5 mol% or less, based on the total acid component or the total alcohol component, but exceeds 10 mol%. And the high workability of the film which is an advantage of the polyester resin is not expressed.
Further, if necessary, fatty acids such as lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid and ester-forming derivatives thereof, benzoic acid, p-tert-butylbenzoic acid, cyclohexane acid, High-boiling monocarboxylic acids such as 4-hydroxyphenyl stearic acid, high-boiling monoalcohols such as stearyl alcohol and 2-phenoxyethanol, hydroxycarboxylic acids such as ε-caprolactone, lactic acid, β-hydroxybutyric acid, and p-hydroxybenzoic acid Or an ester-forming derivative thereof.

The glass transition temperature (Tg) of the resin (a) is preferably 50 ° C. to 100 ° C., more preferably 52 ° C. to 75 ° C., from the viewpoints of heat resistance during storage and stress resistance. If the Tg is lower than the temperature at which the aqueous resin dispersion is produced, the effect of preventing coalescence or preventing splitting is reduced, and the effect of improving the uniformity of particle size is reduced. In addition, Tg of resin (a) in this invention is a value calculated | required from DSC measurement or a flow tester measurement (when it cannot measure by DSC).
(DSC measurement conditions)
Device: DSC (TA Instruments, Q2000)
What filled 5-10 mg of samples in the aluminum simple airtight bread | pan was used for the following measurement flows.
1st Heating: 30 ° C. to 220 ° C., 5 ° C./min. Hold for 1 minute after reaching 220 ° C. Cooling: Quench to −20 ° C. without temperature control, hold for 1 minute after reaching −20 ° C. 2nd Heating: −20 ° C. to 180 ° C., 5 ° C./min.
The glass transition temperature was evaluated by adopting the midpoint method in the 2nd Heating thermogram and reading the value.
(Flow tester measurement conditions)
Load: 30 kg / cm ² , temperature rising rate: 3.0 ° C./min,
Die diameter: 0.50 mm, Die length: 10.0 mm

(CCA)
The toner of the present invention can contain a charge control agent in the toner as needed.
For example, nigrosine, azine dyes containing an alkyl group having 2 to 16 carbon atoms (Japanese Patent Publication No. 42-1627), basic dyes such as C.I. I. Basic Yellow 2 (C.I. 41000), C.I. I. Basic Yellow 3, C.I. I. Basic Red 1 (C.I. 45160), C.I. I. Basic Red 9 (C.I. 42500), C.I. I. Basic Violet 1 (C.I. 42535), C.I. I. Basic Violet 3 (C.I. 42555), C.I. I. Basic Violet 10 (C.I. 45170), C.I. I. Basic Violet 14 (C.I. 42510), C.I. I. Basic Blue 1 (C.I. 42025), C.I. I. Basic Blue 3 (C.I. 51005), C.I. I. Basic Blue 5 (C.I. 42140), C.I. I. Basic Blue 7 (C.I. 42595), C.I. I. Basic Blue 9 (C.I. 52015), C.I. I. Basic Blue 24 (C.I. 52030), C.I. I. Basic Blue 25 (C.I. 52025), C.I. I. Basic Blue 26 (C.I. 44045), C.I. I. Basic Green 1 (C.I. 42040), C.I. I. Basic Green 4 (C.I. 42000) and the like and lake pigments of these basic dyes, C.I. I. Solvent Black 8 (C.I. 26150), quaternary ammonium salts such as benzoylmethyl hexadecyl ammonium chloride, decyl trimethyl chloride, or dialkyl tin compounds such as dibutyl or dioctyl, dialkyl tin borate compounds, guanidine derivatives, containing amino groups Polyamine resins such as vinyl polymers, condensation polymers containing amino groups, etc. Metal complex salts of monoazo dyes described, Japanese Patent Publication No. 55-42752, Japanese Patent Publication No. 59-7385, salicylic acid, dialkylsalicylic acid, naphthoic acid, dicarboxylic acid Zn, Al, Co, Cr , Fe, etc. Metal complex, a copper phthalocyanine pigment obtained by sulfonation, organic boron salts, fluorine-containing quaternary ammonium salts, calixarene compounds, and the like. Naturally, color toners other than black should avoid the use of charge control agents that impair the desired color, and white metal salts of salicylic acid derivatives are preferably used.

  The content of the charge control agent in the toner composition is preferably 0.1 to 10 wt%, and more preferably 0.2 to 5 wt%, for example, with respect to the binder resin. If the content is less than 0.1 wt%, the required charge amount may not be obtained. If the content exceeds 10 wt%, the charge of the toner becomes too large, and the effect of the main charge control agent is reduced. In addition, the electrostatic attraction force with the developing roller may increase, leading to a decrease in toner fluidity and a decrease in image density.

(Coloring agent)
As the colorant used in the toner of the present invention, known pigments and dyes capable of obtaining toners of yellow, magenta, cyan and black colors can be used.
Examples of yellow pigments include cadmium yellow, mineral fast yellow, nickel titanium yellow, navel yellow, naphthol yellow S, Hansa Yellow G, Hansa Yellow 10G, Benzidine Yellow GR, Quinoline Yellow Lake, Permanent Yellow NCG and Tartrazine Lake. Can be mentioned.
Examples of the orange pigment include molybdenum orange, permanent orange GTR, pyrazolone orange, Vulcan orange, indanthrene brilliant orange RK, benzidine orange G, and indanthrene brilliant orange GK.
Examples of red pigments include Bengala, Cadmium Red, Permanent Red 4R, Resol Red, Pyrazolone Red, Watching Red Calcium Salt, Lake Red D, Brilliant Carmine 6B, Eosin Lake, Rhodamine Lake B, Alizarin Lake, Brilliant Carmine 3B.

Examples of purple pigments include fast violet B and methyl violet lake.
Examples of blue pigments include cobalt blue, alkali blue, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, phthalocyanine blue partially chlorinated, first sky blue, and indanthrene blue BC.
Examples of the green pigment include chrome green, chromium oxide, pigment green B, and malachite green lake.
Examples of black pigments include azine dyes such as carbon black, oil furnace black, channel black, lamp black, acetylene black, and aniline black, metal salt azo dyes, metal oxides, and composite metal oxides.
These can use 1 type (s) or 2 or more types.

  The content of the colorant in the toner material is preferably 1 to 15 wt%, and more preferably 3 to 10 wt%. If this content is less than 1 wt%, sufficient color may not be imparted to the toner, and if it exceeds 15 wt%, pigment dispersion in the toner tends to occur and a favorable coloring power cannot be obtained. In addition, the electrical characteristics of the toner may be deteriorated.

(Release agent)
As the release agent used for the toner in the present invention, all known ones can be used, and in particular, the free fatty acid type carnauba wax, polyethylene wax, montan wax and oxidized rice wax can be used alone or in combination. . The carnauba wax is preferably a microcrystalline one, having an acid value of 5 or less and a particle size of 1 μm or less when dispersed in a toner binder. The montan wax generally refers to a montan wax refined from a mineral, and like a carnauba wax, it is preferably a microcrystal and an acid value of 5 to 14 mgKOH / g. The oxidized rice wax is obtained by oxidizing rice bran wax with air, and its acid value is preferably 10 to 30 mgKOH / g. The reason is that these waxes are finely dispersed in the toner binder resin of the present invention, so that it is easy to obtain a toner excellent in offset prevention, transferability and durability as described later. These waxes can be used alone or in combination of two or more.
As other mold release agents, any conventionally known mold release agents such as solid silicone wax, higher fatty acid higher alcohol, montan ester wax, polyethylene wax and polypropylene wax can be mixed and used.

  The Tg of the release agent used in the toner of the present invention is preferably 70 to 90 ° C. If it is less than 70 ° C., the heat-resistant storage stability of the toner is deteriorated, and if it exceeds 90 ° C., the releasability at a low temperature is not expressed, the cold offset resistance is deteriorated, and the paper is wound around the fixing machine. The amount of these release agents used is 1 to 20% by mass, preferably 3 to 10% by mass, based on the toner resin component. If it is less than 1% by mass, the effect of preventing offset is insufficient, and if it exceeds 20% by mass, transferability and durability are deteriorated.

  In the resin particles (C) of the present invention, the resin particles (A) containing the first resin (a) or the coating (P) containing the resin (a) contains the second resin (b). As long as it is attached to the resin particles (B), it may be obtained by any manufacturing method.

The resin particles (C) of the present invention may be resin particles produced by any method and process, but as a method for producing resin particles, the following production method (I) or (II), etc. Is mentioned.
(I): An aqueous dispersion (W) of resin particles (A) containing resin (a) and [resin (b) or an organic solvent solution or dispersion thereof (hereinafter referred to as (O))) are mixed. And (O) is dispersed in (W) to form resin particles (B) containing (b) in (W). In this case, simultaneously with the granulation of the resin particles (B), the resin particles (A) or the coating (P) adhere to the surface of (B) to form an aqueous dispersion (X) of the resin particles (C). Built by removing.

  (II): A method of producing resin particles (C) by coating resin particles (B) containing a resin (b) prepared in advance with a coating agent (W ′) containing a resin (a). In this case, the coating agent (W ′) may be liquid, solid, or any form, and after coating with the precursor (a ′) of (a), (a ′) is reacted (a ). Further, (B) to be used may be a resin particle produced by an emulsion polymerization aggregation method, a resin particle produced by a pulverization method, or any production method. . The coating method is not limited. For example, a resin particle (B) or a dispersion of (B) prepared in advance in an aqueous dispersion (W) of resin particles (A) containing resin (a) is dispersed. And a method of sprinkling (B) the solution of (a) as a coating agent. Among these, the production method (I) is preferable.

The resin particles (C) are more preferably obtained by the following production method because the resin particles have a uniform particle size.
An aqueous dispersion (W) of resin particles (A) and (O) (resin (b) or an organic solvent solution or dispersion thereof)) are mixed, and (O) is dispersed in (W). When the resin particles (B) containing (b) are formed, the resin particles (C) are prevented from coalescing by adsorbing the resin particles (A) on the surface of the resin particles (B), In addition, (C) is less likely to be split under high shear conditions. Thereby, the particle diameter of (C) is converged to a constant value, and the effect of improving the uniformity of the particle diameter is exhibited. Therefore, the resin particles (A) have such a strength that they are not destroyed by shearing at the temperature at which they are dispersed, are not easily dissolved or swelled in water, and (b) or an organic solvent solution or dispersion thereof. A preferable characteristic is that it is difficult to dissolve in the liquid.
In addition, a colorant, a release agent, and a modified layered inorganic mineral that are toner components are included in the resin particles (B). For this reason, before mixing (W) and (O), it is dispersed in the solution of (O). The charge control agent may be included in the resin particles (B) or externally added. In the case of inclusion, it may be dispersed in the solution of (O) in the same manner as the colorant and the like, and in the case of external addition, it is externally added after the formation of the particles C.

  As for the shelled state of the toner, for example, the toner is embedded in an epoxy resin, cut into an ultrathin section of about 100 μm, stained with ruthenium tetroxide, and then observed at a magnification of 10,000 times with a transmission electron microscope (TEM). This can be confirmed by taking a picture and evaluating the picture. Since the toner base resin, WAX, pigment, and shell layer materials are different, the dyeing states are different. It can be measured by observing the outer periphery of the toner particle cross section and confirming whether or not a dyed layer different from the base resin exists on the entire circumference. When it is confirmed only on a part of the outer periphery, or when a part that is confirmed in the majority but not partially present is confirmed, it can be determined that the toner is not shelled.

(Developer)
The developer contains at least the toner of the present invention, and other components appropriately selected such as a carrier. The developer may be a one-component developer or a two-component developer. However, when it is used for a high-speed printer or the like corresponding to the recent improvement in information processing speed, the life is improved. In view of the above, the two-component developer is preferable.

(Career)
There is no restriction | limiting in particular as a carrier, Although it can select suitably according to the objective, What has a core material and the resin layer which coat | covers this core material is preferable.
There is no restriction | limiting in particular as a material of the said core material, It can select suitably from well-known things, For example, 50-90 emu / g manganese-strontium (Mn-Sr) type material, manganese-magnesium (Mn-) Mg) -based materials and the like are preferable, and highly magnetized materials such as iron powder (100 emu / g or more) and magnetite (75 to 120 emu / g) are preferable in terms of securing image density. In addition, the copper-zinc (Cu-Zn) system (30 to 80 emu / g) or the like is advantageous in that it can weaken the contact with the electrostatic latent image carrier in which the toner is in a spiked state, and is advantageous in improving the image quality. The weakly magnetized material is preferred. These may be used alone or in combination of two or more.

  The particle diameter of the core material is preferably an average particle diameter (weight average particle diameter (D50)) of 10 to 200 μm, and more preferably 40 to 100 μm. When the average particle diameter (weight average particle diameter (D50)) is less than 10 μm, in the distribution of carrier particles, the fine powder system increases, the magnetization per particle is lowered, and carrier scattering may occur. If it exceeds 200 μm, the specific surface area may decrease and toner scattering may occur, and in the case of a full color with many solid portions, reproduction of the solid portions may be particularly poor.

  The material of the resin layer is not particularly limited and can be appropriately selected from known resins according to the purpose. For example, amino resins, polyvinyl resins, polystyrene resins, halogenated olefin resins, Polyester resin, polycarbonate resin, polyethylene resin, polyvinyl fluoride resin, polyvinylidene fluoride resin, polytrifluoroethylene resin, polyhexafluoropropylene resin, copolymer of vinylidene fluoride and acrylic monomer, vinylidene fluoride And fluorinated terpolymers (triple fluorinated (multiple) copolymers) such as terpolymers of tetrafluoroethylene, vinylidene fluoride and non-fluorinated monomers, silicone resins, etc. It is done. These may be used individually by 1 type and may use 2 or more types together. Among these, a silicone resin is particularly preferable.

The silicone resin is not particularly limited and can be appropriately selected according to the purpose from generally known silicone resins. For example, a straight silicone resin consisting only of an organosilosan bond; an alkyd resin; Examples thereof include polyester resins, epoxy resins, acrylic resins, silicone resins modified with urethane resins, and the like.
Commercially available products can be used as the silicone resin. Examples of straight silicone resins include KR271, KR255, and KR152 manufactured by Shin-Etsu Chemical Co., Ltd .; SR2400, SR2406, and SR2410 manufactured by Toray Dow Corning Silicone Co., Ltd. Etc.
Commercially available products can be used as the modified silicone resin. For example, KR206 (alkyd modified), KR5208 (acryl modified), ES1001N (epoxy modified), KR305 (urethane modified) manufactured by Shin-Etsu Chemical Co., Ltd .; SR2115 (epoxy-modified), SR2110 (alkyd-modified) manufactured by Dow Corning Silicone Co., Ltd., and the like.
In addition, although a silicone resin can be used alone, it is also possible to simultaneously use a component that undergoes a crosslinking reaction, a charge amount adjusting component, and the like.

The resin layer may contain conductive powder or the like as necessary. Examples of the conductive powder include metal powder, carbon black, titanium oxide, tin oxide, and zinc oxide. The average particle diameter of these conductive powders is preferably 1 μm or less. When the average particle diameter exceeds 1 μm, it may be difficult to control electric resistance.
For example, the resin layer is prepared by dissolving the silicone resin or the like in a solvent to prepare a coating solution, and then uniformly coating the coating solution on the surface of the core material by a known coating method, drying, and baking. It can be formed by doing. Examples of the application method include an immersion method, a spray method, and a brush coating method.

There is no restriction | limiting in particular as said solvent, Although it can select suitably according to the objective, For example, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cellosolve, butyl acetate, etc. are mentioned.
The baking is not particularly limited, and may be an external heating method or an internal heating method. For example, a stationary electric furnace, a fluid electric furnace, a rotary electric furnace, a burner furnace, etc. The method of using, the method of using a microwave, etc. are mentioned.

The amount of the resin layer in the carrier is preferably 0.01 to 5.0% by mass. When the amount is less than 0.01% by mass, the uniform resin layer may not be formed on the surface of the core material. When the amount exceeds 5.0% by mass, the resin layer becomes thick. In some cases, granulation of carriers occurs, and uniform carrier particles may not be obtained.
When the developer is a two-component developer, the content of the carrier in the two-component developer is not particularly limited and may be appropriately selected depending on the intended purpose, for example, 90 to 98 mass. % Is preferable, and 93 to 97% by mass is more preferable.
In general, the mixing ratio of the toner and carrier of the two-component developer is preferably 1 to 10.0 parts by mass of toner with respect to 100 parts by mass of carrier.

<Image Forming Method and Image Forming Apparatus>
A charging process for charging the surface of the electrostatic latent image carrier, an exposure process for exposing the charged electrostatic latent image carrier surface to form an electrostatic latent image, and developing the electrostatic latent image using toner. An image forming method including at least a developing step for forming a visible image, a transferring step for transferring the visible image to a recording medium, and a fixing step for fixing the transferred image transferred to the recording medium. The toner of the present invention is used as the toner.
Furthermore, the image forming apparatus of the present invention exposes the electrostatic latent image carrier surface by exposing the latent image carrier (photoconductor), charging means for charging the surface of the electrostatic latent image carrier, and electrostatically. An exposure unit that forms a latent image; a developing unit that develops the electrostatic latent image with toner to form a visible image; a transfer unit that transfers the visible image to a recording medium; It has at least fixing means for fixing the transferred image, and includes the toner of the present invention as toner.

(Image forming device)
An outline of an image forming apparatus using the toner of the present invention will be described below.
The image forming apparatus of the present invention comprises an electrostatic latent image carrier (photosensitive member), a charging unit for charging the surface of the electrostatic latent image carrier, and the electrostatic latent image carrier surface exposed to electrostatic charge. An exposure unit that forms a latent image; a developing unit that develops the electrostatic latent image with toner to form a visible image; a transfer unit that transfers the visible image to a recording medium; It has at least fixing means for fixing the transferred image, and the toner of the present invention is used as the toner to be used.
A copying machine as an example of the electrophotographic image forming apparatus of the present invention is shown in FIG.
FIG. 1 shows an example of an internal configuration diagram of a color image forming apparatus according to an embodiment of the present invention. This specific example is a tandem indirect transfer type electrophotographic copying apparatus, but the image forming apparatus of the present invention is not limited to this specific example.

  In the figure, reference numeral 100 denotes a copying apparatus main body, 200 a paper feed table on which the copying apparatus main body 100 is mounted, 300 a scanner (reading optical system) mounted on the copying apparatus main body 100, and 400 an automatic document feeder (ADF) mounted thereon. ). An endless belt-like intermediate transfer member 10 extending in the lateral direction is provided at the center position of the copying apparatus main body 100. In the illustrated example, the intermediate transfer member is wound around three support rollers 14, 15, and 16 so as to be able to rotate and convey clockwise in the drawing. In this illustrated example, an intermediate transfer body cleaning device 17 that removes residual toner remaining on the intermediate transfer body 10 after image transfer is provided to the left of the second support roller 15 among the three support rollers. Further, among the three support rollers, the intermediate transfer member 10 stretched between the first support roller 14 and the second support roller 15 has black, yellow, magenta, and cyan along the transport direction. The tandem image forming unit 20 is configured by arranging the four image forming units 18 side by side. An exposure device 21 is further provided immediately above the tandem image forming unit 20 as shown in the figure. On the other hand, a secondary transfer device 22 is provided on the opposite side of the intermediate transfer body 10 from the tandem image forming unit 20. In the illustrated example, the secondary transfer device 22 is configured by spanning a secondary transfer belt 24, which is an endless belt, between two rollers 23, and is pressed against the third support roller 16 via the intermediate transfer body 10. The image on the intermediate transfer body 10 is transferred to a sheet. A fixing device 25 for fixing the transfer image on the sheet is provided beside the secondary transfer device 22. The fixing device 25 is configured by pressing a pressure roller 27 against a fixing belt 26 that is an endless belt. The secondary transfer device 22 described above also has a sheet transport function for transporting the image-transferred sheet to the fixing device 25. In the illustrated example, a sheet reversing device 28 for reversing the sheet so as to record images on both sides of the sheet is provided below the secondary transfer device 22 and the fixing device 25 in parallel with the tandem image forming unit 20 described above. Is provided.

  Now, when making a copy using this color electrophotographic apparatus, a document is set on the document table 30 of the automatic document feeder 400. Alternatively, the automatic document feeder 400 is opened, a document is set on the contact glass 32 of the scanner 300, and the automatic document feeder 400 is closed and pressed by it. When a start switch (not shown) is pressed, when a document is set on the automatic document feeder 400, the document is transported and moved onto the contact glass 32, and then the document is set on the other contact glass 32. Immediately, the scanner 300 is driven, and the first traveling body 33 and the second traveling body 34 travel. Then, the first traveling body 33 emits light from the light source and further reflects the reflected light from the document surface toward the second traveling body 34, and is reflected by the mirror of the second traveling body 34 and passes through the imaging lens 35. The document is placed in the reading sensor 36 and the original content is read. When a start switch (not shown) is pressed, one of the support rollers 14, 15 and 16 is rotationally driven by a drive motor (not shown), and the other two support rollers are driven to rotate, so that the intermediate transfer body 10 is moved. Rotate and convey. At the same time, the individual image forming means 18 rotates the photoconductor 40 to form black, yellow, magenta, and cyan monochrome images on each photoconductor 40.

  Then, along with the conveyance of the intermediate transfer member 10, the single color images are sequentially transferred to form a composite color image on the intermediate transfer member 10. On the other hand, when a start switch (not shown) is pressed, one of the paper feed rollers 42 of the paper feed table 200 is selectively rotated, and the sheet is fed out from one of the paper feed cassettes 44 provided in multiple stages in the paper bank 43, and the separation roller 45. Then, the sheets are separated one by one into the paper feed path 46, transported by the transport roller 47, guided to the paper feed path 48 in the copying machine main body 100, and abutted against the registration roller 49 and stopped. Then, the registration roller 49 is rotated in synchronization with the composite color image on the intermediate transfer member 10, the sheet is fed between the intermediate transfer member 10 and the secondary transfer device 22, and transferred by the secondary transfer device 22. A color image is recorded on the sheet. The image-transferred sheet is conveyed by the secondary transfer device 22 and sent to the fixing device 25. The fixing device 25 applies heat and pressure to fix the transferred image. Are discharged and stacked on the discharge tray 57. Alternatively, it is switched by the switching claw 55 and put into the sheet reversing device 28, where it is reversed and guided again to the transfer position, and an image is recorded also on the back surface, and then discharged onto the discharge tray 57 by the discharge roller 56. On the other hand, the intermediate transfer body 10 after the image transfer is removed by the intermediate transfer body cleaning device 17 to remove residual toner remaining on the intermediate transfer body 10 after the image transfer, so that the tandem image forming unit 20 can prepare for another image formation.

FIG. 2 shows a schematic configuration of a process cartridge using the developing method of the present invention. In FIG. 2, 1 indicates the entire process cartridge, 2 indicates a photosensitive member, 3 indicates a charging unit, 4 indicates a developing unit, and 5 indicates a cleaning unit.
In the present invention, a plurality of components such as the photosensitive member 2, the charging unit 3, the developing unit 4, the cleaning unit 5 and the like described above are integrally coupled as a process cartridge, and the process cartridge is configured as a copying machine. And an image forming apparatus main body such as a printer.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not limited to this. In the following description, “part” means “part by mass”.

(Manufacture of resin b)
Into a 300 mL four-necked separable flask, the materials shown in Table 1 for the oligomer raw materials are put in the number of parts shown in Table 1, the internal temperature is gradually raised to 150 ° C., and then dehydrated for 30 minutes at 10 mmHg. It was. Next, the temperature was raised to 170 ° C. under N ₂ purge, and after confirming that the system was homogenized by visual observation, 0.05 part by mass of tin 2-ethylhexanoate was added to the system to perform a polymerization reaction. . At this time, the internal temperature of the system was controlled so as not to exceed 190 ° C. After the reaction time of 2 hours, the system was again switched to the outflow line and delactideed at 190 ° C. and 10 mmHg to complete the polymerization reaction. Thereafter, the internal temperature was gradually raised to 120 ° C. After confirming the homogenization of the system under visual observation, dehydration treatment was performed at 10 mmHg for 10 min. Subsequently, the internal temperature was cooled to 50 ° C., and 50 parts by mass of dehydrated ethyl acetate was added to completely dissolve the oligomer. Thereafter, 0.02 part by mass of tin 2-ethylhexanoate was added to the system, and then the extension reaction shown in Table 1 was gradually added in the number of parts shown in Table 1 to start the extension reaction. At this time, the internal temperature of the system was controlled to be 80 to 85 ° C. After the reaction time of 4 hours had elapsed, the internal temperature was raised to 100 ° C. to remove ethyl acetate in the reaction solution, and finally the reaction solution was taken out and dried in a dryer at 120 ° C. for 3 hours to obtain resin b -1 to 18 were obtained.

The optical purities, aromatic diol weight ratios, oligomer molecular weights, and molecular weights after elongation of the resins b-1 to b-18 are as shown in Table 2.
In addition, the molecular weight of the component used by the Example and the comparative example was measured with the following method.
(Measurement of molecular weight)
Apparatus: GPC (manufactured by Tosoh Corporation), detector: RI, measurement temperature: 40 ° C,
Mobile phase: tetrahydrofuran, flow rate: 0.45 mL / min.
The molecular weight Mn, Mw, and the molecular weight distribution Mw / Mn are respectively a number average molecular weight, a weight average molecular weight, and a molecular weight measured by GPC (gel permeation chromatography) using a calibration curve prepared with a polystyrene sample having a known molecular weight as a standard. Distribution.

(Production of fine particle dispersion a1)
In a reaction vessel equipped with a stir bar and a thermometer, 600 parts of water, 135 parts of styrene, 110 parts of methacrylic acid, 50 parts of butyl acrylate, 13 parts of alkylallylsulfosuccinate sodium salt (Eleminol JS-2, manufactured by Sanyo Chemical Industries) Then, 2 parts of ammonium persulfate was charged and stirred at 400 rpm for 20 minutes, whereby a white emulsion was obtained. The system was heated to raise the system temperature to 75 ° C. and reacted for 6 hours. Further, 30 parts of a 1% ammonium persulfate aqueous solution was added, and the mixture was aged at 75 ° C. for 6 hours, and an aqueous dispersion of a vinyl resin (a copolymer of styrene-methacrylic acid monobutyl methacrylate-alkylallylsulfosuccinic acid sodium salt) [fine particle dispersion a1] was obtained. The volume average particle diameter of [fine particle dispersion a1] measured by ELS-800 was 0.09 μm. A portion of [fine particle dispersion a1] was dried to isolate the resin component, and the glass transition temperature measured by a flow tester was 76 ° C.

(Production of fine particle dispersion a2)
In a reaction vessel equipped with a stir bar and a thermometer, 600 parts of water, 120 parts of styrene, 100 parts of methacrylic acid, 55 parts of butyl acrylate, 20 parts of alkylallylsulfosuccinate sodium salt (Eleminol JS-2, manufactured by Sanyo Chemical Industries) When 1 part of ammonium persulfate was charged and stirred at 400 rpm for 20 minutes, a white emulsion was obtained. The system was heated to raise the system temperature to 75 ° C. and reacted for 6 hours. Further, 50 parts of a 1% ammonium persulfate aqueous solution was added, and the mixture was aged at 75 ° C. for 6 hours, and an aqueous dispersion of a vinyl resin (a copolymer of styrene / methacrylic acid / butyl methacrylate / alkylallylsulfosuccinate sodium salt) [fine particle dispersion a2] was obtained. The volume average particle diameter of [fine particle dispersion a2] measured by ELS-800 was 0.07 μm. A part of [fine particle dispersion a2] was dried to isolate a resin component, and the glass transition temperature was 73 ° C. as measured by a flow tester of the resin component.

(Production of fine particle dispersion a3)
A mixture comprising 1600 parts of terephthalic acid, 95 parts of isophthalic acid, 410 parts of ethylene glycol and 730 parts of neopentyl glycol was heated in an autoclave at 260 ° C. for 2.5 hours to carry out an esterification reaction. Next, 0.25 parts of germanium dioxide as a catalyst was added, the temperature of the system was raised to 280 ° C. in 30 minutes, and the pressure of the system was gradually reduced to 0.1 Torr after 1 hour. Under this condition, the polycondensation reaction was continued. After 1.5 hours, the system was brought to atmospheric pressure with nitrogen gas, the temperature of the system was lowered, and when 260 ° C was reached, 55 parts of isophthalic acid and 40 parts of trimellitic anhydride were added. The mixture was stirred at 255 ° C. for 30 minutes and discharged into a sheet. Then, after sufficiently cooling to room temperature, the mixture was pulverized with a crusher, and a [Polyester resin a3] having a mesh opening of 1 to 6 mm was obtained using a sieve. [Polyester resin a3] had an acid value of 28.5 mgKOH / g, a weight average molecular weight Mw of 11500, and a Tg of 65 ° C.
In a 2L glass container with a jacket, 200 parts of the above-mentioned [polyester resin a3], 35 parts of ethylene glycol mono-n-butyl ether, polyvinyl alcohol (Unitika Ltd. “Unitika Poval” 050G) 0.5% by weight aqueous solution (hereinafter referred to as PVA) -1) 460 parts and N, N-dimethylethanolamine (hereinafter referred to as DMEA) corresponding to 1.2 times equivalent of the total amount of carboxyl groups contained in the polyester resin were added, and this was opened in a tabletop type homo When stirring at 6,000 rpm using Disper (Special Machine Industries Co., Ltd., TK Robotics), it was confirmed that no precipitation of resin particles was observed at the bottom of the container, and it was in a completely floating state. It was done. Therefore, this state was maintained, and hot water was passed through the jacket after 10 minutes for heating. When the temperature in the container reached 68 ° C., the stirring was set at 7,000 rpm, the temperature in the container was kept at 68 to 70 ° C., and the mixture was further stirred for 20 minutes to obtain a milky white uniform aqueous dispersion. Then, cold water was poured into the jacket, cooled to room temperature while stirring at 3500 rpm, and filtered using a stainless steel filter (635 mesh, plain weave). As a result, almost no resin particles remained on the filter. The obtained fine particle dispersion had a volume average particle size of 0.09 μm. A portion of [fine particle dispersion a3] was dried to isolate the resin component, and the glass transition temperature was 69 ° C. by flow tester measurement of the resin component.

(Production of fine particle dispersion a4)
A mixture comprising 1800 parts of terephthalic acid, 90 parts of isophthalic acid, 450 parts of ethylene glycol and 700 parts of neopentyl glycol was heated in an autoclave at 260 ° C. for 2.5 hours to carry out an esterification reaction. Next, 0.25 parts of germanium dioxide as a catalyst was added, the temperature of the system was raised to 280 ° C. in 30 minutes, and the pressure of the system was gradually reduced to 0.1 Torr after 1 hour. Under this condition, the polycondensation reaction is continued. After 1.5 hours, the system is brought to atmospheric pressure with nitrogen gas, the temperature of the system is lowered, and when it reaches 260 ° C., 50 parts of isophthalic acid and 45 parts of trimellitic anhydride are added. The mixture was stirred at 255 ° C. for 30 minutes and discharged into a sheet. And after fully cooling to room temperature, this was grind | pulverized with the crusher, and the [polyester resin a4] of a 1-6 mm fraction was obtained using the sieve. [Polyester resin a4] had an acid value of 30.2 mgKOH / g, a weight average molecular weight Mw of 10300, and a Tg of 62 ° C.
In a 2 L glass container with a jacket, 200 parts of the above-mentioned [Polyester resin a4], 35 parts of ethylene glycol mono-n-butyl ether, polyvinyl alcohol (Unitika Ltd. “Unitika Poval” 050G) 0.5% by weight aqueous solution (hereinafter referred to as PVA) -1) 500 parts and N, N-dimethylethanolamine (hereinafter referred to as DMEA) corresponding to 1.2 equivalents of the total amount of carboxyl groups contained in the polyester resin were added, and this was opened in a tabletop type homo When stirring at 6,000 rpm using Disper (Special Machine Industries Co., Ltd., TK Robotics), it was confirmed that no precipitation of resin particles was observed at the bottom of the container, and it was in a completely floating state. It was done. Therefore, this state was maintained, and hot water was passed through the jacket after 10 minutes for heating. When the temperature in the container reached 68 ° C., the stirring was set at 7,000 rpm, the temperature in the container was kept at 68 to 70 ° C., and the mixture was further stirred for 20 minutes to obtain a milky white uniform aqueous dispersion. Then, cold water was poured into the jacket, cooled to room temperature while stirring at 3500 rpm, and filtered using a stainless steel filter (635 mesh, plain weave). As a result, almost no resin particles remained on the filter. The obtained fine particle dispersion had a volume average particle size of 0.11 μm. A portion of [fine particle dispersion a4] was dried to isolate the resin component, and the glass transition temperature measured by flow tester measurement of the resin component was 67 ° C.

(Adjustment of aqueous medium)
In 300 parts by mass of ion-exchanged water, 300 parts by mass of [fine particle dispersions a1 to 4] and 0.2 part by mass of sodium dodecylbenzenesulfonate are mixed and stirred to dissolve uniformly to prepare an aqueous medium phase. Media 1 to 4] were obtained.

(Production of master batch)
1,000 parts by mass of water, 530 parts by mass of carbon black (Printex 35, manufactured by Degussa) having a DBP oil absorption of 42 ml / 100 g and a pH of 9.5, and 1200 parts by mass of resin were added to a Henschel mixer (Mitsui Mining Co., Ltd.). And mixed). The resulting mixture was kneaded at 150 ° C. for 30 minutes using two rolls, then rolled and cooled, and pulverized with a pulverizer (manufactured by Hosokawa Micron Corporation) to prepare a master batch.

(Synthesis of ketimine compounds)
In a reaction vessel equipped with a stir bar and a thermometer, 30 parts by mass of isophoronediamine and 70 parts by mass of methyl ethyl ketone were charged and reacted at 50 ° C. for 5 hours to synthesize a ketimine compound. The obtained ketimine compound had an amine value of 423 mgKOH / g.

Examples 1-15, Comparative Examples 1-3
(Preparation of toner base particles)
[Resin b-1 to 18] and 80 parts by mass of ethyl acetate were added to the reaction vessel in the number of parts shown in Table 3 and stirred to prepare resin solutions 1 to 18.
Next, carnauba wax (molecular weight 1,800, acid value 2.7 mgKOH / g, penetration of 1.7 mm (40 ° C.)) and a masterbatch were charged in resin solutions 1 to 18 in parts by mass shown in Table 3. , Using a bead mill ultra visco mill (manufactured by Imex), 3 passes under the condition that the liquid feeding speed is 1 kg / hour, the disk peripheral speed is 6 m / second, and the particle diameter is filled with 80% by volume of 0.5 mm zirconia beads. Toner material liquids 1 to 18 were obtained.
Next, the aqueous media 1 to 4 are put in the container in the number of parts shown in Table 3, and the toner material liquids 1 to 1 are stirred while stirring at 12,000 rpm using a TK homomixer (manufactured by Special Machine Industries Co., Ltd.). 100 parts by mass of 18 was added and mixed for 10 minutes to obtain an emulsified slurry. Furthermore, 100 parts by mass of the emulsified slurry was charged in a Kolben equipped with a stirrer and a thermometer, and the solvent was removed at 30 ° C. for 10 hours while stirring at a stirring peripheral speed of 20 m / min, to obtain dispersion slurries 1-18.

Next, 100 parts by mass of each of the dispersion slurries 1 to 18 was filtered under reduced pressure, 100 parts by mass of ion-exchanged water was added to the obtained filter cake, and the mixture was mixed at 12,000 rpm for 10 minutes using a TK homomixer. And filtered. To the obtained filter cake, 300 parts by mass of ion-exchanged water was added, mixed for 10 minutes at 12,000 rpm using a TK homomixer, and then filtered twice. To the obtained filter cake, 20 parts of a 10% by mass aqueous sodium hydroxide solution was added, mixed at 12,000 rpm for 30 minutes using a TK homomixer, and then filtered under reduced pressure. To the obtained filter cake, 300 parts by mass of ion-exchanged water was added, mixed at 12,000 rpm for 10 minutes using a TK homomixer, and then filtered. To the obtained filter cake, 300 parts by mass of ion-exchanged water was added, mixed for 10 minutes at 12,000 rpm using a TK homomixer, and then filtered twice. After adding 20 mass parts of 10 mass% hydrochloric acid to the obtained filter cake and mixing for 10 minutes at 12,000 rpm using a TK type homomixer, the fluorine-type quaternary ammonium salt compound tergent F-310 (Neos) Was added with a 5% methanol solution so that the fluorine-based quaternary ammonium salt was equivalent to 0.1 part by mass with respect to 100 parts by mass of the solid content of the toner, stirred for 10 minutes, and then filtered. To the obtained filter cake, 300 parts by mass of ion-exchanged water was added, mixed for 10 minutes at 12,000 rpm using a TK homomixer, and then filtered twice to obtain a filter cake. Using a circulating dryer, the obtained filter cake was dried at 40 ° C. for 36 hours, and sieved with a mesh having an opening of 75 μm to prepare toner base particles 1-18.
The obtained toner base particles 1 to 18 are observed with a transmission electron microscope (TEM) at a magnification of 10,000 times, photographed, and image evaluation of the photograph to observe the outer periphery of the toner particle cross section. did. For toner base particles 1 to 17, it was confirmed that a dyed state layer different from that of the base resin was present on the entire circumference. However, for toner base particle 18, the above-mentioned different dyed state layer was on the outer periphery of the cross section of the toner particle. Only a part was confirmed.

(Production of toner)
100 parts by mass of the obtained toner base particles 1 to 18 and 1.0 part by mass of hydrophobic silica (H2000, manufactured by Clariant Japan) as an external additive were used using a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.). After 5 cycles of mixing at a peripheral speed of 30 m / sec for 30 seconds and resting for 1 minute, sieved with a mesh having an opening of 35 μm, toners 1 to 18 were produced.

(Creation of carrier)
To 100 parts by mass of toluene, 100 parts by mass of a silicone resin (organostraight silicone), 5 parts by mass of γ- (2-aminoethyl) aminopropyltrimethoxysilane, and 10 parts by mass of carbon black are added and dispersed for 20 minutes with a homomixer. To prepare a resin layer coating solution. Using a fluidized bed type coating apparatus, the resin layer coating solution was applied to the surface of 1,000 parts by mass of spherical magnetite having a volume average particle size of 50 μm to prepare a carrier.

(Create developer)
Each developer of Examples 1 to 15 and Comparative Examples 1 to 3 was prepared by mixing 5 parts by mass of each of the toners 1 to 18 and 95 parts by mass of the carrier.

The obtained toner or developer was used for evaluation as follows.
<Fixability>
As a fixing roller, an electrophotographic copying machine using a Teflon (registered trademark) roller (MF-200, manufactured by Ricoh Co., Ltd.) is used to change the temperature of the fixing belt, by changing the fixing unit. A solid image having a toner adhesion amount of 0.85 ± 0.1 mg / cm ² was formed on a paper and cardboard transfer paper type 6200 (manufactured by Ricoh Co., Ltd.) and copy printing paper <135> (manufactured by NBS Ricoh Co., Ltd.). . At this time, the lower limit temperature at which the residual ratio of the image density after rubbing the solid image with thick paper with a pad was 70% or more was defined as the minimum fixing temperature. C or higher is practical.
[Evaluation criteria for minimum fixing temperature]
A: Fixing lower limit temperature is less than 135 ° C. B: Fixing lower limit temperature is from 135 ° C. to less than 145 ° C. C: Fixing lower limit temperature is from 145 ° C. to less than 155 ° C. D: Fixing lower limit temperature is 155 ° C. or more

<Heat resistant storage stability (Penetration)>
A 50 ml glass container is filled with toner, left in a thermostatic bath at 50 ° C. for 24 hours, then cooled to 24 ° C., and the penetration (mm) is measured by a penetration test (JIS K2235-1991). The heat resistant storage stability was evaluated according to the following criteria. In addition, the greater the penetration, the better the heat-resistant storage stability. If the penetration is less than 5 mm, there is a high possibility of problems in use, and C or more is practical. is there.
〔Evaluation criteria〕
A: Needle penetration is 25 mm or more B: Needle penetration is 15 mm or more and less than 25 mm C: Needle penetration is 5 mm or more and less than 15 mm D: Needle penetration is less than 5 mm

<Charge amount distribution>
As for the charge amount distribution, the Q / d distribution (fC / μm) is measured with respect to the produced developer using a charge amount distribution measuring device (Espert Analyzer, manufactured by Hosokawa Micron Corporation), and the half width is obtained from the measured value. It was. In addition, as a measurement condition of the Espert Analyzer (E-SPART ANALYZER), the nitrogen gas flow rate was 0.3 NL / min and the gas pressure was 0.3 atm. As an index indicating the distribution of the charge amount, it is expressed by the mode (peak value) [q / d] and the distribution width (half width) at the half height position of the most frequent. It was evaluated with. C or higher is practical.
〔Evaluation criteria〕
A: Mode value 0.25 fC / μm or more and less than half value width 0.2 B: Mode value 0.20 or more and less than 0.25 fC / μm or half value width 0.2 or more and less than 0.3 C: Mode value 0 .15 or more and less than 0.20 fC / μm or half-value width 0.3 or more and less than 0.4 D: Mode value less than 0.15 fC / μm and half-width 0.4 or more

<Change in toner charge over time>
Charge amount immediately after mixing 0.6 g of toner and 19.4 g of silicone ferrite carrier (manufactured by Kanto Denka Kogyo Co., Ltd., average particle diameter: 90 μm) in a 50 ml plastic bottle and mixing for 60 seconds at 250 r / min using a ball mill Was measured using a q / m meter (manufactured by EPPING) and used as the initial charge amount. Similarly, the charge amount after shaking the plastic bottle containing the toner and the silicone ferrite carrier 300 times was defined as the charge amount with time. Thereafter, changes with time in the charge amount were evaluated according to the following evaluation criteria.
C or higher is practical.
〔Evaluation criteria〕
A: Charge amount with time is 80% or more of initial charge amount B: Charge amount with time is 70% or more and less than 80% of initial charge amount C: Charge amount with time is 60% or more and less than 70% of initial charge amount D: Time Charge amount is less than 60% of initial charge amount

  Any toner using a polylactic acid-containing resin exhibits sufficient low-temperature fixability, but none of the toners of Comparative Examples 1 to 3 are practical in terms of heat-resistant storage stability. On the other hand, the toner of the present invention using a resin modified by adding an aromatic ring-containing component to polylactic acid exhibited an effect that both low-temperature fixability and heat-resistant storage stability were compatible.

JP-A-9-319144 JP 2002-284881 A Japanese Patent No. 3640918 Japanese Patent No. 2909873 JP 7-33861 A JP 59-96123 A JP 2010-014757 A

DESCRIPTION OF SYMBOLS 1 Process cartridge 2 Photoconductor 3 Charging means 4 Developing means 5 Cleaning means 10 Intermediate transfer body 14,15,16 Support roller 17 Intermediate transfer body cleaning device 18 Image forming means 20 Tandem image forming portion 22 Secondary transfer device 24 Secondary transfer Belt 25 Fixing device 26 Fixing belt 27 Pressure roller 28 Sheet reversing device 30 Document table 32 Contact glass 33 First traveling member 34 Second traveling member 35 Imaging lens 36 Reading sensor 40 Photosensitive member 42 Paper feeding roller 43 Paper bank 44 Feeding Paper cassette 45 Separating roller 46 Paper feed path 47 Transport roller 48 Paper feed path 49 Registration roller 55 Switching claw 56 Ejection roller 57 Ejection tray 60 Charging device 61 Development device 62 Primary transfer device 64 Static elimination device 63 Photoconductor cleaning device 61 Development 86 devices Toner supply side stirring chamber 87 development side stirring chamber 68 developing sleeve 75 toner density sensor 77 doctor blade 87 second developer stirring chamber 80 partition plate 100 copying machine main body 200 paper feed table 300 scanner 400 automatic document feeder (ADF)

Claims (16)

  The resin particle (A) containing the first resin (a) or the coating (P) containing the resin (a) is attached to the surface of the resin particle (B) containing the second resin (b). A toner comprising resin particles (C) having a structure as described above, wherein the resin (b) is a straight chain obtained by extending an oligomer having a polyhydroxycarboxylic acid skeleton obtained from a diol containing an aromatic ring and a hydroxycarboxylic acid. An electrophotographic toner, characterized by being a polyester.   2. The electrophotographic toner according to claim 1, wherein the linear polyester has a glass transition temperature of 60 ° C. or higher and 75 ° C. or lower.   The electrophotographic toner according to claim 1, wherein the oligomer having the polyhydroxycarboxylic acid skeleton has a number average molecular weight of 2000 to 5000.   The toner for electrophotography according to claim 1, wherein the linear polyester has a number average molecular weight of 7,000 to 30,000.   The electrophotographic toner according to claim 1, wherein the total weight ratio of the aromatic ring-containing diol part to the linear polyester is 10 wt% or more and 50 wt% or less.   The polyhydroxycarboxylic acid skeleton contains a polyhydroxycarboxylic acid skeleton composed of an optically active monomer, and the polyhydroxycarboxylic acid skeleton composed of the optically active monomer has an optical purity X (%) = | X (L form in terms of monomer component) ) -X (D isomer) | [where X (L isomer) is the L isomer ratio (mol%) in terms of optically active monomer, and X (D isomer) is the D isomer ratio (mol%) in terms of optically active monomer). The toner for electrophotography according to claim 1, wherein the toner represents 80% or less.   7. The electrophotographic toner according to claim 1, wherein the diol containing an aromatic ring is bis (2-hydroxyethyl) terephthalate (BHET).   The electrophotographic toner according to claim 1, wherein a diisocyanate compound is used as an extender when the oligomer having a polyhydroxycarboxylic acid skeleton is extended.   The toner for electrophotography according to claim 1, wherein the resin (a) is polyester.   The electrophotographic toner according to claim 1, wherein the toner contains a colorant.   The toner for electrophotography according to claim 1, wherein the toner contains a release agent.   The toner for electrophotography according to claim 1, wherein the toner contains a charge control agent.   A developer using the electrophotographic toner according to claim 1.   An electrostatic latent image carrier, a charging unit for charging the surface of the electrostatic latent image carrier, an exposure unit for exposing the charged electrostatic latent image carrier surface to form an electrostatic latent image, and the static Developing means for developing an electrostatic latent image with toner to form a visible image; Transfer means for transferring the visible image to a recording medium; Fixing means for fixing the transferred image transferred to the recording medium; An image forming apparatus having at least the toner, wherein the toner is an electrophotographic toner according to claim 1.   A charging process for charging the surface of the electrostatic latent image carrier, an exposure process for exposing the charged electrostatic latent image carrier surface to form an electrostatic latent image, and developing the electrostatic latent image using toner. An image forming method including at least a developing step for forming a visible image, a transferring step for transferring the visible image to a recording medium, and a fixing step for fixing the transferred image transferred to the recording medium. An image forming method, wherein the toner is the electrophotographic toner according to claim 1.   The image forming apparatus main body includes at least an electrostatic latent image carrier and developing means for developing the electrostatic latent image formed on the electrostatic latent image carrier using toner to form a visible image. A process cartridge which is detachable, wherein the toner is the electrophotographic toner according to claim 1.

Images