JP6525739B2 - Magnetic toner - Google Patents

Description

  The present invention relates to toners used in imaging methods such as electrophotography, electrostatic recording and toner jet methods.

  A number of methods are known as electrophotography. In general, a photoconductive substance is used, and an electrostatic latent image is formed on an electrostatic charge image carrier (hereinafter also referred to as "photosensitive member") by various means. Next, the latent image is developed with toner to form a visible image, and if necessary, the toner image is transferred to a recording medium such as paper, and then the toner image is fixed on the recording medium by heat or pressure, etc. To get Examples of the image forming apparatus using such an electrophotographic method include a copier and a printer.

  In these printers and copiers, the transition from analog to digital advances, and the latent image is excellent in reproducibility and high resolution, and at the same time, stable image quality is required even in long-term use. Furthermore, toners with good fixability are required as energy saving measures, and improvements are made to binder resins and waxes to improve fixability.

  Here, focusing on the wax, it is generally known that the viscosity at the time of melting decreases and the fixability improves by using a large amount of the wax. On the other hand, when a large amount of wax is used, durability and storage stability tend to be poor, and conventionally, a balance between fixability, durability and storage stability has been achieved by combining with means such as external addition.

  However, such toners with improved fixability are likely to suffer from problems such as deterioration in developability and transferability as they unify and deform in a state after long-term use. The present inventors particularly considered the transferability as a problem and focused on it.

  Many techniques for improving development using crystalline polyester as a method for improving fixability have been conventionally disclosed (for example, Patent Document 1 and Patent Document 2). However, even these proposed crystalline polyester-containing toners are insufficient for maintaining the transferability deterioration associated with long-term use, and improvements are required.

JP, 2014-35506, A Patent 4571975

  An object of the present invention is to provide a magnetic toner which is excellent in fixability and excellent in transferability in long-term use.

  The aforementioned problems are solved by the present invention described below.

The toner of the present invention is a magnetic toner having magnetic toner particles containing a binder resin, crystalline polyester and a magnetic material,
The binder resin contains 70% by mass or more of a styrene acrylic resin based on the mass of the binder resin,
The crystalline polyester is
i) The melting point (Tm) is 55 ° C. or more and 90 ° C. or less,
ii) having polyester moieties and vinyl polymer moieties,
ii-1) the polyester moiety has a unit represented by the following formula (1),
ii-2) the weight average molecular weight (Mw) of the vinyl polymer moiety is 3,000 or more and 40000 or less,
A silane compound having a partial structure represented by the following formula (2) is immobilized and present on the surface of the magnetic substance,
The difference between the solubility parameter of the partial structure represented by the solubility parameter and the lower following formula units represented by the following following formula (1) (2) is 0.80 to 1.20, and wherein the .

（式（１）中、ｍは４〜１４の整数、ｎは６〜１６の整数を表す。）

(In formula (1) , m is an integer of 4-14, n represents the integer of 6-16.)

（式（２）中、Ｒは炭素数３以上の炭化水素基を表す。）

(In formula (2) , R represents a hydrocarbon group having 3 or more carbon atoms.)

  According to the present invention, it is possible to provide a magnetic toner having excellent fixability and excellent transferability in long-term use.

FIG. 1 is a schematic cross-sectional view showing an example of an image forming apparatus that can suitably use the toner of the present invention.

  First, consider the transfer process in electrophotography. In the transfer step, a transfer bias is applied to a transfer roller or the like to electrostatically attach the toner image on the latent image carrier to a medium such as paper. According to the study of the present inventors, when the magnetic substance is unevenly present (hereinafter, "locally distributed particles") in the magnetic toner particles or a large number of irregularly shaped particles and coalescent particles are found, the transferability tends to be inferior. The

  Particles having nonuniform magnetic dispersion, such as unevenly distributed particles, often have insufficient developability as well as transferability. Therefore, for example, when used for a long time in a laser beam printer without replenishment, unevenly distributed particles, irregularly shaped particles, and coalescent particles accumulate in the developing device, and the transferability tends to decrease relative to the initial stage.

  On the other hand, there is also a need to improve the fixability. Conventionally, a method of adding low melting point wax or crystalline polyester has been used to improve fixing. However, such materials often heat and melt while oozing out to the surface. During long-term use, for example, in a system in which stirring is provided in a magnetic toner carrier or a developing device, the magnetic toner locally receives heat due to rubbing with these members. At that time, due to the exudation of the low melting point material, formation of coalesced particles or deformation of the particles may occur, and also in this case, the transferability is lowered as described above.

  As a result of intensive investigations by the present inventors regarding the combination of the structure of the crystalline polyester and the magnetic material with respect to the problem of the transferability deterioration when such magnetic toner is used for a long time, the above problems can be solved in a specific combination. It came to the end and found the invention. The toner of the present invention will be described below.

The toner of the present invention is a magnetic toner having magnetic toner particles containing a binder resin, crystalline polyester and a magnetic material,
The binder resin contains 70% by mass or more of a styrene acrylic resin based on the mass of the binder resin,
The crystalline polyester is
i) The melting point (Tm) is 55 ° C. or more and 90 ° C. or less,
ii) having polyester moieties and vinyl polymer moieties,
ii-1) the polyester moiety has a unit represented by the following formula (1),
ii-2) the weight average molecular weight (Mw) of the vinyl polymer moiety is 3,000 or more and 40000 or less,
A silane compound having a partial structure represented by the following formula (2) is immobilized and present on the surface of the magnetic substance,
The difference between the solubility parameter of the partial structure represented by the solubility parameter and the lower following formula units represented by the following following formula (1) (2) is 0.80 to 1.20, and wherein the It is a thing.

（式（１）中、ｍは４〜１４の整数、ｎは６〜１６の整数を表す。）

(In formula (1) , m is an integer of 4-14, n represents the integer of 6-16.)

（式（２）中、Ｒは炭素数３以上の炭化水素基を表す。）

(In formula (2) , R represents a hydrocarbon group having 3 or more carbon atoms.)

[Crystalline polyester]
In the present invention, the fact that the resin is "crystalline" means that the resin is an endothermic peak observed in differential scanning calorimetry (DSC).

The crystalline polyester used in the present invention is
i) melting point 55-90 ° C.,
ii) having polyester moieties and vinyl polymer moieties.

  The melting point is preferably in the above range from the viewpoint of developability, fixability, and toner production stability.

  Next, the vinyl polymer portion of crystalline polyester will be described. The magnetic toner of the present invention contains a styrene acrylic resin, which is excellent in terms of material dispersibility, ease of application to various toner production methods, and development and transferability. According to the study of the present inventors, although the polyester and the styrene acrylic resin have low affinity and are difficult to be compatible with each other, the compatibility can be greatly improved by introducing a vinyl polymer site into the crystalline polyester.

  Focusing on the polyester portion, polyester has a large number of highly polar ester bonds. On the other hand, in the magnetic substance, since a silane compound having a partial structure represented by the formula (2) is immobilized on the surface, a large number of siloxane bonds are present on the surface, but the siloxane bonds also have high polarity. . Therefore, the polyester of the near polarity and the magnetic material of the present invention tend to be compatible.

  That is, since the crystalline polyester having the vinyl polymer moiety is compatible with both the styrene acrylic resin and the magnetic substance of the present invention, it functions as a dispersion aid for the magnetic substance, so that the uneven distribution of the magnetic substance as described above can be obtained. I think that I was able to suppress it.

  However, the effect on the magnetic substance dispersion was observed only in the case of the combination in which the crystalline polyester and the magnetic substance satisfy the specific conditions. The above conditions were first the relationship between the solubility parameters of the magnetic substance and the crystalline polyester, the structure of the magnetic surface, the molecular weight of the vinyl polymer moiety of the crystalline polyester, and the structure of the polyester moiety.

  First, the relationship between the solubility parameters of the magnetic substance and the crystalline polyester will be described. The specific range is that the difference between the solubility parameter of the unit represented by formula (1) and the solubility parameter of the partial structure represented by formula (2) is 0.80 or more and 1.20 or less. The unit represented by the formula (1) refers to the structure of the polyester portion. Moreover, the solubility parameter said here is obtained from the formula of Fedors mentioned later, and generally the solubility parameter is so easy to be compatible that the difference of the numerical value of each other is small. However, according to the study of the present inventors, it was found that although it is preferable that the numerical values of the crystalline polyester and the magnetic material be close, they need to be separated to some extent. It is believed that this is because the crystalline polyester of the present invention is compatible with both the styrene acrylic resin and the magnetic material, and therefore excessive interaction between the polyester moiety and the magnetic material inhibits the interaction between the vinyl polymer and the styrene acrylic. There is.

  Second, the surface structure of the magnetic substance will be described. The magnetic substance needs to have a silane compound having a partial structure represented by Formula (2) immobilized on the surface. Immobilization of the silane compound on the surface of the magnetic substance is carried out with the aim of enhancing the dispersibility in the resin by imparting hydrophobicity. When the carbon number of R is 3 or less, sufficient hydrophobicity is obtained, and it is easy to be included in toner particles even when manufactured in an aqueous medium.

  Third, the molecular weight of the vinyl polymer moiety of the crystalline polyester is described. While the vinyl polymer portion needs to have a certain length in order to exert a dispersing effect to the styrene acrylic resin, it is not effective when the length is too short. Specifically, the weight average molecular weight (Mw) had to be 3,000 to 40,000. This is a range in which the crystalline polyester not only has a sufficiently high affinity to the styrene acrylic resin, but is also in a range in which the fixability is also excellent. Furthermore, since the viscosity at the time of melting of the crystalline polyester slightly increases by bonding the vinyl polymer portion, there is a tendency to suppress the exudation when receiving local heat. The molecular weight of the vinyl polymer moiety is more preferably 4000 to 15000 from the viewpoint of fixability.

  Fourth, the polyester portion of the crystalline polyester of the present invention will be described. The polyester moiety has a unit shown in Formula (1). This indicates that the repeating unit has a structure in which a dicarboxylic acid having 4 to 14 (m = 4 to 14) methylene groups and a diol having 6 to 16 (n = 6 to 16) methylene groups are condensed. ing. In the crystalline polyester of the present invention, the structure derived from the above-mentioned repeating unit is preferably 90% by mass or more in the entire polyester part of the crystalline polyester. When the number of methylene groups in the formula (1) falls within the defined range, appropriate hydrophobicity is obtained, and the compatibility with the styrene acrylic resin is appropriate.

  Further, from the viewpoint of transferability and developability, m + n is preferably 10 to 22. By appropriately adjusting m and n within this range, the melting point of the crystalline polyester and the solubility parameter of the polyester portion can be controlled.

  Furthermore, it is also preferable that the difference between the average value of m and n in the formula (1) and the carbon number of R in the formula (2) is 2 to 6 from the viewpoint of transferability and developability.

The presence or absence of the styrene acrylic resin, and the structure and content of the crystalline polyester can be confirmed by the following method. First, tetrahydrofuran is added to the magnetic toner to dissolve most of the resin components. Here, materials other than resin, such as magnetic substances and external additives, are removed by centrifugation using a specific gravity difference. Thereafter, the tetrahydrofuran soluble component by structural analysis such as nuclear magnetic resonance spectroscopy ^{(1 H-NMR),} it is possible to know styrene-acrylic resin is contained. The resin fraction remaining in the dissolution is a mixture containing the crystalline polyester and the releasing agent as the main components, and therefore, after isolating the crystalline polyester by preparative LC, such as nuclear magnetic resonance spectroscopy ( ¹ H-NMR), etc. Structural analysis can identify the structure.

  With regard to the content of the crystalline polyester in the magnetic toner, by comparing the nuclear magnetic resonance spectroscopy analysis results of the magnetic toner itself and the crystalline polyester after separation, the peak area ratio specific to the crystalline polyester is taken. can get. From the structure of the crystalline polyester thus obtained, the solubility parameter is obtained by the calculation method described later.

  Furthermore, by separately preparing a calibration curve of the amount of vinyl polymer and peak area in nuclear magnetic resonance spectroscopy, the content of vinyl polymer in the crystalline polyester can be known from the results of nuclear magnetic resonance spectroscopy. Taking their mass ratio gives a ratio based on mass of polyester moiety of the crystalline polyester and vinyl polymer moiety.

  The solubility parameter can be controlled by the type and amount of added monomers. In order to increase the solubility parameter, it is sufficient to add a monomer having a large solubility parameter (short monomer of carbon chain), and to reduce the solubility parameter, a monomer having small solubility parameter (long monomer of carbon chain) Can be added.

  The unit represented by the above formula (1) can be obtained by condensation of a dicarboxylic acid and a diol.

  As the dicarboxylic acid, adipic acid, suberic acid, sebacic acid, dodecanedioic acid, tetradecanedioic acid, hexadecanedioic acid and the like can be used.

  As the diol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, 1,14- Tetradecanediol, 1,16-hexadecanediol and the like can be used.

  In addition, known vinyl monomers such as styrene, methyl methacrylate or n-butyl acrylate can be used for the vinyl polymer portion of the crystalline polyester of the present invention. Particularly preferably, styrene is effectively used as a site compatible with the styrene acrylic resin, and plasticity at the time of melting is more exhibited.

  In the crystalline polyester, the ratio based on the mass of the polyester moiety and the vinyl polymer moiety (polyester moiety / vinyl polymer moiety) is preferably 40/60 to 95/5, more preferably 40/60 to 80/20. . Within this range, sufficient low-temperature fixability can be obtained due to the sharp meltability which is the characteristic of the polyester portion, and at the same time, the transferability is excellent.

  The crystalline polyester in the present invention is preferably a block polymer having a polyester portion and a vinyl polymer portion.

  The polyester portion having crystallinity facilitates design for achieving both compatibility with the styrene acrylic resin and maintenance of crystallinity at the time of toner addition. Further, by having the vinyl polymer portion which is non-crystalline, it is possible to finely disperse the crystalline polyester in the styrene acrylic resin, and the low temperature fixing property is further improved. Moreover, since it takes a form in which the crystalline part and the amorphous part are connected by the main chain if it is a block polymer, the three-dimensional structure is not taken, so the dispersed state with respect to the styrene acrylic resin is uniform, and in long-term use Also excellent in transferability.

  In addition, as a definition of a block polymer, a polymer composed of a plurality of linearly connected blocks (a glossary of basic terms of polymer science by the International Pure Applied Chemistry Association Polymer Nomenclature Committee of the Polymer Society of Japan) and Yes, and the invention follows its definition.

The content of the crystalline polyester, 100 parts by mass of the binder resin Ri those other is preferably from 2.0 to 40.0 parts by weight, more preferably from 2.0 to 30.0 parts by weight. When the content of the crystalline polyester is 2.0 parts by mass or more, the fixing property and the effect on the magnetic material dispersion, which are the effects of the present invention, are improved. When the amount of the crystalline polyester is 40.0 parts by mass or less, the surface leaching amount of the crystalline polyester is suppressed, and the transferability is excellent.

  The weight average molecular weight of the crystalline polyester is preferably from 1,200 to 45,000. Within this range, it is preferable from the viewpoint of transferability and fixability, because the compatibility with the styrene acrylic resin is excellent while exhibiting the dispersing effect of the magnetic material in the magnetic toner particles.

  Although the method for producing the crystalline polyester of the present invention is not particularly limited, it is necessary to select a method for obtaining a structure in which both are chemically bonded, since it contains a polyester moiety and a vinyl polymer moiety. The preferred production method is exemplified below.

  (1) A polyester is obtained by condensation polymerization of a dicarboxylic acid and a diol. At this time, as the esterification catalyst, known esterification catalysts such as tin compounds such as dibutyltin oxide, tin dioctylate, titanium (IV) isopropoxide and the like and titanium compounds may be used. Next, a monomer having an unsaturated group and having a functional group capable of transesterification such as a carboxyl group or an ester group and a vinyl monomer such as styrene or (meth) acrylic acid are added to proceed polymerization. The desired polymer is obtained. In the case of preparation by such a manufacturing method, a graft structure is partially taken because a reaction of crosslinking polyester portions occurs during vinyl polymer production. Therefore, the present inventors refer to such crystalline polyester as a graft polymer.

  (2) A vinyl polymer of one end or both ends is a carboxylic acid or a carboxylic ester is produced, and a diol and a dicarboxylic acid are appropriately added to the vinyl polymer, and then a polycondensation reaction is allowed to proceed to obtain a target polymer. With respect to the condensation polymerization reaction, a known esterification catalyst can be used as in (1). As a known method, a method using a functional group-containing initiator or a method using a functional group-containing chain transfer agent can be mentioned for producing a vinyl polymer having one end or both ends at carboxylic acid or carboxylic acid ester. As a method of using a functional group containing initiator, for example, Koji Ishizu, "Journal of Polymer Science Part A: Polymer Chemistry", (USA), John Wiley & Sons, 1990, Vol. 28, pp. 1887-1894. As a method of using a functional group-containing chain transfer agent, for example, Toshiro Uchida, 4 others, “Journal of Polymer Science Part A: Polymer Chemistry”, (US), John Wiley & Sons, 2000, Vol. 38, 3052 -3058 pages. ]. Those prepared by such a process take the form of block polymers as described above.

  (3) A polyester is obtained as in (1). Thereafter, according to ATRP method, a polyester portion and a vinyl polymer portion block copolymer are obtained. By using so-called precise radical polymerization, it is possible to prepare a polymer in which polyester and vinyl polymer are present one block at a time in one molecule. Those prepared by such a process take the form of block polymers as described above.

  The monomer which has an unsaturated group and has a functional group which can transesterify is illustrated. Acrylic acid, fumaric acid, methacrylic acid, citraconic acid, maleic acid, 2-hydroxyethyl (meth) acrylate, glycidyl (meth) acrylate, and anhydrides of these carboxylic acids, alkyl (1 to 2 carbon atoms) esters And derivatives thereof. Among these, acrylic acid, methacrylic acid, fumaric acid, maleic acid and derivatives of these carboxylic acids are preferable from the viewpoint of reactivity.

  As a vinyl monomer, the following can be illustrated. Styrene, α-methylstyrene, α-ethylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p Ethylstyrene, 2,4-Dimethylstyrene, p-n-butylstyrene, p-tert-butylstyrene, p-n-hexylstyrene, p-n-octylstyrene, p-n-nonylstyrene, p-n-n-styrene Decylstyrene, p-n-dodecylstyrene, ethylene, propylene, butylene, isobutylene, vinyl chloride, vinylidene chloride, vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, vinyl methyl ketone, vinyl hexyl ketone, methyl isopropenyl ketone, vinyl Naphthalene, Acryloni Tolyl, methacrylonitrile, or acrylamide can be mentioned.

  As a polymerization initiator used to polymerize the vinyl polymer described above when producing a crystalline polyester, an oil-soluble initiator other than those used in the present invention can be used as long as the effects of the present invention are not impaired. Water soluble initiators can be used as appropriate. For example, as oil-soluble initiators, azo compounds such as 2,2'-azobisisobutyronitrile; t-butyl peroxy neodecanoate, t-hexyl peroxy pivalate, lauroyl peroxide, t- Peroxides such as butylperoxy 2-ethylhexanoate, t-butylperoxyisobutyrate, di-t-butylperoxyisophthalate, di-t-butyl peroxide and the like can be mentioned.

  As a water-soluble initiator, ammonium persulfate, potassium persulfate, 2,2'-azobis (N, N'-dimethylene isobutyroamidine) hydrochloride, 2,2'-azobis (2-aminodinopropane) hydrochloric acid Salt, azobis (isobutylamidine) hydrochloride, sodium 2,2'-azobisisobutyronitrile sulfonate, 2,2'-azobis {2-methyl-N- [1,1-bis (hydroxymethyl) -2 -Hydroxyethyl] propionamide}, 2,2'-azobis {2-methyl-N- [2- (1-hydroxybutyl)]-propionamide}, hydrochloride ferrous sulfate or hydrogen peroxide can be mentioned.

[Magnetic substance]
The form of the magnetic material that can be used in the present invention will be described below.

  The magnetic substance of the present invention is one in which a silane compound having a partial structure represented by Formula (2) is immobilized on the surface. This is because, in addition to the purpose of improving the dispersibility inside the toner by the interaction with the crystalline polyester of the present invention as described above, it is very preferable in the case of producing the toner in an aqueous medium.

In order to obtain a magnetic substance on which a silane compound having a partial structure represented by the formula (2) is immobilized, for example, a method of treating the surface of a magnetic substance using a silane coupling agent, a titanium coupling agent or the like is used. It can be mentioned. More preferably used is a silane coupling agent, which is represented by the general formula (I).
R _m SiY _n (I)
[In formula (I) , R represents an alkoxy group, m represents an integer of 1 to 3, Y represents a functional group such as an alkyl group, a vinyl group, an epoxy group, a (meth) acrylic group, and n represents 1 Indicates an integer from 3 to However, m + n = 4. ]

  Examples of the silane coupling agent represented by the general formula (I) include n-propyltrimethoxysilane, isopropyltrimethoxysilane, n-butyltrimethoxysilane, isobutyltrimethoxysilane, n-hexyltrimethoxysilane, n- Octyltrimethoxysilane, n-octyltriethoxysilane, n-decyltrimethoxysilane, n-hexadecyltrimethoxysilane, n-octadecyltrimethoxysilane and the like can be mentioned. In the present invention, those in which Y in the general formula (I) is an alkyl group having 3 or more carbon atoms can be preferably used. Among them, preferred is an alkyl group having 3 to 10 carbon atoms, and particularly preferred is an alkyl group having 3 to 6 carbon atoms.

  When using the said silane coupling agent, it is possible to process independently or to process it together using multiple types. When using several types together, you may process separately with each coupling agent, and you may process simultaneously.

  In the case of dry surface treatment, the magnetic powder washed, filtered and dried is treated with a coupling agent. When the surface treatment is carried out by wet method, the dried product is redispersed after completion of the oxidation reaction, or after completion of the oxidation reaction, the iron oxide body obtained by washing and filtering is not dried but in another aqueous medium. Re-disperse in water and perform the coupling process. In the present invention, both the dry method and the wet method can be appropriately selected.

  In the magnetic substance, it is preferable that the surface treatment agent be fixed on the surface of the magnetic powder to some extent. Specifically, it is preferable from the viewpoint of developability that the amount of carbon derived from the silane compound immobilized on the surface of the magnetic substance is 0.35 to 0.60% by mass on the basis of the magnetic substance.

The magnetic material of the present invention is one which has been subjected to surface treatment after producing a magnetic powder which has not been surface-treated. The magnetic substance is mainly composed of magnetic iron oxide such as triiron tetraoxide or γ-iron oxide, and may contain elements such as phosphorus, cobalt, nickel, copper, magnesium, manganese, aluminum, silicon and the like. These magnetic powders is preferably a BET specific surface area by nitrogen adsorption method is 2~30m ² / g, more preferably 3~28m ² / g. Further, those having a Mohs hardness of 5 to 7 are preferable. The shape of the magnetic powder includes polyhedrons, octahedrons, hexahedrons, spheres, needles, scaly, etc., but those with less anisotropy such as polyhedrons, octahedrons, hexahedrons, spheres etc. It is preferable for enhancing.

  The magnetic body preferably has a number average particle size of 0.10 to 0.40 μm. In general, the smaller the particle diameter of the magnetic substance, the higher the coloring power, but the magnetic substance tends to aggregate, and the uniform dispersibility of the magnetic substance in the toner becomes poor, which is not preferable.

  The number average particle diameter of the magnetic substance can be measured using a transmission electron microscope. Specifically, after the toner particles to be observed are sufficiently dispersed in the epoxy resin, a cured product obtained by curing for 2 days in an atmosphere at a temperature of 40 ° C. is obtained. The resulting cured product is used as a flaky sample by a microtome, and the particle sizes of 100 magnetic substances in the field of view are measured with a photograph of 10,000 to 40,000 magnification in a transmission electron microscope (TEM). Then, the number average particle diameter is calculated based on the equivalent diameter of the circle which is equal to the projected area of the magnetic substance. It is also possible to measure the particle size with an image analysis device.

  The magnetic material used for the toner of the present invention can be produced, for example, by the following method. An alkali such as sodium hydroxide equivalent or more equivalent to the iron component is added to the ferrous salt aqueous solution to prepare an aqueous solution containing ferrous hydroxide. Air is blown while maintaining the pH of the prepared aqueous solution at pH 7 or higher, oxidation reaction of ferrous hydroxide is performed while the aqueous solution is heated to 70 ° C. or higher, and seed crystals to be a core of magnetic iron oxide powder are first Generate

  Next, an aqueous solution containing about 1 equivalent of ferrous sulfate based on the amount of alkali added previously to the slurry liquid containing seed crystals is added. The reaction of ferrous hydroxide is advanced while blowing in air while maintaining the pH of the solution at 5 to 10 to grow magnetic iron oxide powder by using seed crystals as a core. At this time, it is possible to control the shape and magnetic properties of the magnetic substance by selecting any pH, reaction temperature and stirring conditions. As the oxidation reaction proceeds, the pH of the solution shifts to the acid side, but it is preferable not to make the pH of the solution less than 5. A magnetic material can be obtained by filtering, washing and drying the magnetic material thus obtained according to a conventional method.

  In the present invention, other colorants may be used in addition to the magnetic material. Examples of colorants that can be used in combination include magnetic and nonmagnetic inorganic compounds in addition to the above-described known dyes and pigments. Specifically, ferromagnetic metal particles such as cobalt and nickel, or alloys obtained by adding chromium, manganese, copper, zinc, aluminum, rare earth elements, etc. thereto. Particles such as hematite, titanium black, nigrosine dye / pigment, carbon black, phthalocyanine and the like can be mentioned. It is also preferable to use these after treating the surface.

The magnetic toner particles of the present invention, 100 parts by mass of the binder resin Ri those other, to contain the magnetic material of 30.0 to 80.0 parts by weight is preferable because of excellent transferability and developability.

  The content of the magnetic substance in the magnetic toner can be measured using a thermal analyzer TGA7 manufactured by Perkin Elmer. The measuring method is as follows. The toner is heated from normal temperature to 900 ° C. at a temperature rising rate of 25 ° C./min in a nitrogen atmosphere. The weight loss mass% between 100 ° C. and 750 ° C. is used as the binder resin amount, and the remaining mass is approximately used as the magnetic material amount.

  The structure of the silane compound can be confirmed, for example, as follows.

First, the magnetic substance is dispersed and stirred in styrene to wash away the silane compound not immobilized on the surface. After drying the washed magnetic substance, magnetite is dissolved by leaving it in hydrochloric acid for several days. The remaining nuclear magnetic resonance spectroscopy for the silane compound ^{(1 H-NMR, 29Si-} NMR) by structural analysis such as the structure of the silane compound can be identified, specific and solubility of R in formula (2) Parameter values can be calculated.

  In the magnetic toner of the present invention, in order to control the interaction between the crystalline polyester and the magnetic material, it is also preferable to adjust the content ratio of both. Specifically, it is preferable from the viewpoint of developability and transferability that the content of the magnetic substance and the crystalline polyester is, based on the mass, magnetic substance / crystalline polyester = 95/5 to 75/25.

  As described above, the content of the magnetic substance can be measured using a thermal analyzer TGA7 manufactured by Perkin Elmer. In addition, the content of the crystalline polyester can also be obtained by combining the isolation by preparative LC and nuclear magnetic resonance spectroscopy as described above. These numbers are used to obtain mass based ratios.

[Binder resin]
The binder resin used in the toner of the present invention contains 70% by mass or more of a styrene acrylic resin based on the total amount of the binder resin. More preferably, it is 80 mass% or more.

  The styrene acrylic resin is a copolymer of styrene and an acrylic monomer (acrylic acid, acrylic ester, methacrylic acid, methacrylic ester), and, for example, styrene-methyl acrylic copolymer, styrene-acrylic acid Ethyl copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-dimethylaminoethyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer Examples include coalescence, styrene-butyl methacrylate copolymer, styrene-dimethylaminoethyl methacrylate copolymer and the like.

  The binder resin can also be used in combination with other known resins. Other resins include polystyrenes, homopolymers of styrene such as polyvinyl toluene and their substitution products; styrene-propylene copolymers, styrene-vinyl toluene copolymers, styrene-vinyl naphthalene copolymers, styrene-vinyl methyl ether Copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester co-polymer Styrenic copolymers such as polymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl acetate, polyethylene, polypropylene, polyvinyl butyral, silicone resin, polyester resin, polyamide resin, epoxy resin, polyacrylic acid resin And the like.

  As a polymerizable monomer which forms the said styrene acrylic resin, the following can be illustrated. Examples of the styrene-based polymerizable monomer include styrene; styrene-based polymerizable monomers such as α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene and p-methoxystyrene. As an acrylic polymerizable monomer, methyl acrylate, ethyl acrylate, n-propyl acrylate, iso-propyl acrylate, n-butyl acrylate, iso-butyl acrylate, tert-butyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate And acrylic polymerizable monomers such as n-octyl acrylate and cyclohexyl acrylate. As the methacrylic polymerizable monomer, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, iso-propyl methacrylate, n-butyl methacrylate, iso-butyl methacrylate, tert-butyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate And methacrylic polymerizable monomers such as n-octyl methacrylate.

  In addition, the manufacturing method of styrene acrylic resin is not specifically limited, A well-known method can be used.

  The weight average particle size (D4) of the toner produced according to the present invention is preferably 3.0 to 12.0 μm, more preferably 4.0 to 10.0 μm. Within the above range, good fluidity can be obtained and the latent image can be faithfully developed.

  The toner of the present invention can be produced by any known method. First, in the case of manufacturing by a pulverization method, for example, a component necessary as a toner such as a binder resin, a colorant, an ester wax, a low melting point substance, a charge control agent and other additives are mixed with a Henschel mixer, a ball mill, etc. Mix thoroughly with a bowl. Thereafter, the toner material is dispersed or dissolved by melt-kneading using a heat kneader such as a heating roll, a kneader or an extruder, cooled and solidified, crushed, classified, and optionally subjected to surface treatment to obtain toner particles. be able to. The order of classification and surface treatment may be first. In the classification step, it is preferable to use a multi-division classifier in view of production efficiency.

  The pulverizing step can be carried out by a method using a known pulverizing apparatus such as a mechanical impact type or jet type. Further, it is preferable to further heat and pulverize, or to perform a process of additionally applying mechanical impact. In addition, a hot water bath method in which finely pulverized (sorted if necessary) toner particles are dispersed in hot water, a method of passing in a hot air stream, or the like may be used.

  Examples of means for applying mechanical impact force include a method using a mechanical impact crusher such as Kryptron system manufactured by Kawasaki Heavy Industries, Ltd. or a turbo mill manufactured by Turbo Kogyo Co., Ltd. Also, like a device such as Hosokawa Micron's Mechano-Fusion System or Nara Machinery Co., Ltd.'s Hybridization System, the toner is pressed against the inside of the casing by centrifugal force with the blades rotating at high speed, and the force such as compressive force or frictional force. There is a method of applying mechanical impact force to the toner.

  In order to produce the toner particles according to the present invention, although it is possible to produce by the pulverization method as described above, it is also possible to use heavy in aqueous medium like suspension polymerization method, dissolution suspension method, emulsion aggregation method. More suitable are production methods for obtaining toner particles by granulating the combined composition.

  Hereinafter, the method for producing toner particles will be described using the most preferable suspension polymerization method among the methods for producing toner particles that can be used in the present invention.

  A polymerizable monomer, a crystalline resin, a wax, and, if necessary, other additives such as a colorant and a mold release agent, which form the above-mentioned styrene acrylic resin, are added to a homogenizer, ball mill, colloid mill, ultrasonic dispersion machine It is uniformly dissolved or dispersed by a dispersing machine such as A polymerization initiator is dissolved in this to prepare a polymerizable monomer composition. Next, the polymerizable monomer composition is introduced into an aqueous medium containing a dispersion stabilizer to granulate droplets of the polymerizable monomer composition, and then polymerization is performed to produce toner particles. .

  The polymerization initiator may be added simultaneously with the addition of other additives to the polymerizable monomer, or may be mixed immediately before suspension in the aqueous medium. Also, during or immediately after granulation, a polymerization initiator can be added before starting the polymerization reaction.

  In the case of a polymerization method using an aqueous medium as in the suspension polymerization method, it is preferable to add a polar resin to the polymerizable monomer composition. By adding the polar resin, inclusion of the crystalline resin and the wax is promoted.

  When the polar resin is present in the polymerizable monomer composition droplets suspended in the aqueous medium, the polar resin is the interface between the aqueous medium and the polymerizable monomer composition droplets because of the difference in affinity to water. The polar resin is unevenly distributed on the surface of the toner particles because the toner easily migrates to the vicinity. As a result, the toner particles form a core-shell structure.

  The polar resin is preferably a polyester resin or a carboxyl-containing styrene resin. When these polar resins are unevenly distributed on the surface of toner particles to form a shell, the lubricity of the polar resin itself can be expected.

  As polyester resin, resin which carried out condensation polymerization of the acid ingredient monomer and alcohol ingredient monomer which are mentioned below can be used.

  As an acid component monomer, terephthalic acid, isophthalic acid, phthalic acid, fumaric acid, maleic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, camphoric acid Acids, cyclohexanedicarboxylic acids, and trimellitic acids.

  As an alcohol component monomer, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-bis (hydroxymethyl) And the alkylene glycols and polyalkylene glycols of cyclohexane, bisphenol A, hydrogenated bisphenol, ethylene oxide adduct of bisphenol A, propylene oxide adduct of bisphenol A, glycerin, trimethylolpropane and pentaerythritol.

  As the carboxyl group-containing styrene resin, an acrylic acid copolymer of styrene, a methacrylic acid copolymer of styrene, a maleic acid copolymer of styrene and the like are preferable, and a styrene-acrylic acid ester-acrylic acid copolymer is particularly preferable. The amount of charge can be easily controlled, which is preferable.

  The carboxyl group-containing styrenic resin more preferably contains a monomer having a primary or secondary hydroxyl group. As a specific polymer composition, styrene-2-hydroxyethyl methacrylate-methacrylic acid-methyl methacrylate copolymer, styrene-n-butyl acrylate-2-hydroxyethyl methacrylate-methacrylic acid-methacrylic acid methyl copolymer And styrene-α-methylstyrene-2-hydroxyethyl methacrylate-methacrylic acid-methacrylic acid methyl methacrylate copolymer and the like. A resin containing a monomer having a primary or secondary hydroxyl group has high polarity, and the long-term storage stability is better.

  The content of the polar resin is preferably 1.0 to 20.0 parts by mass, and more preferably 2.0 to 10.0 parts by mass with respect to 100.0 parts by mass of the binder resin.

  Known waxes may be used in the present invention. Specifically, petroleum waxes such as paraffin wax, microcrystalline wax, petrolatum and derivatives thereof, montan wax and derivatives thereof, hydrocarbon waxes and derivatives thereof by Fischer-Tropsch method, polyolefin waxes represented by polyethylene and derivatives thereof, Natural waxes such as carnauba wax and candelilla wax and derivatives thereof can be mentioned, and derivatives include oxides, block copolymers with vinyl monomers, and graft modified products. In addition, alcohols such as higher aliphatic alcohols; fatty acids such as stearic acid and palmitic acid or compounds thereof; acid amides, esters, ketones, hydrogenated castor oil and derivatives thereof, vegetable waxes, animal waxes and the like. These can be used alone or in combination.

  Among these, when using a polyolefin, a hydrocarbon wax by a Fischer-Tropsch method, or a petroleum wax, the effect of improving the developability and the transferability is further enhanced. In addition, an antioxidant may be added to these wax components as long as the charging properties of the toner are not affected. Moreover, it is preferable to use 1.0 to 30.0 mass parts of these wax components with respect to 100.0 mass parts of binder resin.

  The melting point of the wax component used in the present invention is preferably in the range of 30 to 120 ° C., more preferably in the range of 60 to 100 ° C.

  By using the wax component exhibiting the above thermal characteristics, the mold release effect is efficiently exhibited, and a sufficient fixing area is secured.

  When toner particles are obtained using a suspension polymerization method, it is preferable to use a colorant that has been subjected to a hydrophobization treatment with a substance that does not inhibit polymerization, in consideration of the polymerization inhibition property of the colorant and the aqueous phase migration property. .

  Moreover, a charge control agent can also be used as needed. As the charge control agent, known ones can be used, but a charge control agent which has a high triboelectric charging speed and can stably maintain a constant triboelectric charge amount is preferable. Furthermore, when toner particles are produced by a suspension polymerization method, a charge control agent that has low polymerization inhibition and is substantially free of a soluble matter in an aqueous medium is required.

  The charge control agent may be one that controls the toner to be negatively chargeable or one that controls to be positively chargeable. Examples of controlling the toner to be negatively chargeable include the following. Monoazo metal compounds, acetylacetone metal compounds, aromatic oxycarboxylic acids, aromatic dicarboxylic acids, metal compounds of oxycarboxylic acids and dicarboxylic acids, aromatic oxycarboxylic acids, aromatic mono and polycarboxylic acids and metal salts thereof, Anhydrides, esters, phenol derivatives such as bisphenol, urea derivatives, metal-containing salicylic acid compounds, metal-containing naphthoic acid compounds, boron compounds, quaternary ammonium salts, calixarenes, and charge control resins can be mentioned.

  Examples of charge control agents that control the toner to be positively chargeable include the following. Guanidine compounds; imidazole compounds; tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, quaternary ammonium salts such as tetrabutylammonium tetrafluoroborate, and onium salts such as phosphonium salts that are analogs thereof And their lake pigments; triphenylmethane dyes and their lake pigments (as lakeing agents, phosphotungstic acid, phosphomolybdic acid, phosphotungstic molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide, and Ferrocyanides); metal salts of higher fatty acids; charge control resins.

  The charge control agents described above can be used alone or in combination of two or more.

  Among these charge control agents, metal-containing salicylic acid type compounds are preferable, and those in which the metal is aluminum or zirconium are particularly preferable.

  The addition amount of the charge control agent is preferably 0.01 to 20.0 parts by mass, and more preferably 0.5 to 10.0 parts by mass with respect to 100.0 parts by mass of the binder resin.

  Further, as the charge control resin, it is preferable to use a polymer or copolymer having a sulfonic acid group, a sulfonic acid group or a sulfonic acid ester group. As a polymer having a sulfonic acid group, a sulfonic acid group or a sulfonic acid ester group, it is particularly preferable to contain a sulfonic acid group-containing acrylamide monomer or a sulfonic acid group-containing methacrylamide monomer in a copolymerization ratio of 2% by mass or more . More preferably, the content is 5% by mass or more in copolymerization ratio. The charge control resin preferably has a glass transition temperature (Tg) of 35 to 90 ° C., a peak molecular weight (Mp) of 10,000 to 30,000, and a weight average molecular weight (Mn) of 25,000 to 50,000. . When this charge control resin is used, preferable triboelectric charging characteristics can be imparted without affecting the thermal characteristics required for toner particles. Furthermore, since the charge control resin contains a sulfonic acid group, the dispersibility of the charge control resin itself in the dispersion of the colorant and the dispersibility of the colorant are improved, and the coloring power, transparency, and The triboelectric charging characteristics can be further improved.

  A polymerization initiator may be used to polymerize the polymerizable monomer. Examples of the polymerization initiator that can be used in the present invention include organic peroxide initiators and azo polymerization initiators. Examples of the organic peroxide initiator include the following. Benzoyl peroxide, lauroyl peroxide, di-α-cumyl peroxide, 2,5-dimethyl-2,5-bis (benzoylperoxy) hexane, bis (4-t-butylcyclohexyl) peroxydicarbonate, 1-bis (t-butylperoxy) cyclododecane, t-butylperoxymaleic acid, bis (t-butylperoxy) isophthalate, methyl ethyl ketone peroxide, tert-butyl peroxy-2-ethylhexanoate, diisopropyl Peroxy carbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide, and tert-butyl-peroxypivalate.

  As an azo polymerization initiator, 2,2'-azobis- (2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1,1'-azobis (cyclohexane-1-carbonitrile) And 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, and azobismethylbutyronitrile and the like.

  Further, as a polymerization initiator, a redox initiator in which an oxidizing substance and a reducing substance are combined can also be used. Examples of the oxidizing substance include hydrogen peroxide, inorganic peroxides of persulfates (sodium salt, potassium salt and ammonium salt) and oxidizing metal salts of tetravalent cerium salt. As the reducing substance, reducing metal salts (divalent iron salts, monovalent copper salts, and trivalent chromium salts), ammonia, lower amines (methylamines, and methylamines, and having 1 to 6 carbon atoms such as ethylamine) ), Amino compounds such as hydroxylamine, sodium thiosulfate, sodium hydrosulfite, sodium bisulfite, sodium sulfite, and reducible sulfur compounds of sodium formaldehyde sulfoxylate, lower alcohols (with 1 to 6 carbon atoms) And ascorbic acid or salts thereof, and lower aldehydes (having 1 to 6 carbon atoms).

  The polymerization initiator is selected with reference to a 10-hour half-life temperature, and is used alone or in combination. Although the addition amount of the said polymerization initiator changes with the polymerization degree made into the objective, generally 0.5-20.0 mass parts is added with respect to 100.0 mass parts of polymerizable monomers.

  It is also possible to further add and use known chain transfer agents or polymerization inhibitors in order to control the degree of polymerization.

  When the polymerizable monomer is polymerized, various crosslinking agents can also be used. As a crosslinking agent, divinylbenzene, 4,4'-divinylbiphenyl, ethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol diacrylate, diethylene glycol dimethacrylate, glycidyl acrylate, glycidyl methacrylate, trimethylolpropane triacrylate, trimethylolpropane triacrylate Mention may be made of multifunctional compounds such as methacrylates.

  As a dispersion stabilizer used when preparing an aqueous medium, the dispersion stabilizer of a well-known inorganic compound and the dispersion stabilizer of an organic compound can be used. As a dispersion stabilizer for inorganic compounds, tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate And barium sulfate, bentonite, silica, and alumina. On the other hand, dispersion stabilizers for organic compounds include polyvinyl alcohol, gelatin, methyl cellulose, methyl hydroxypropyl cellulose, ethyl cellulose, sodium salt of carboxymethyl cellulose, polyacrylic acid and salts thereof, and starch. The amount of the dispersion stabilizer used is preferably 0.2 to 20.0 parts by mass with respect to 100.0 parts by mass of the polymerizable monomer.

  When a dispersion stabilizer of an inorganic compound is used, a commercially available product may be used as it is, but the inorganic compound may be formed in an aqueous medium to obtain a dispersion stabilizer having a finer particle size. For example, in the case of tricalcium phosphate, it can be obtained by mixing an aqueous solution of sodium phosphate and an aqueous solution of calcium chloride under high stirring.

  To the toner particles, an external additive may be externally added to impart various properties to the toner. Examples of external additives for improving the flowability of toner include inorganic fine particles such as fine particles of silica, fine particles of titanium oxide, and fine particles of double oxides thereof. Among the inorganic fine particles, silica fine particles and titanium oxide fine particles are preferable. For example, the toner of the present invention can be obtained by externally adding and mixing inorganic fine particles to toner particles and adhering them to the surface of the toner particles. The external addition of the inorganic fine particles can be performed by a known method, and examples thereof include a method of performing a mixing treatment using an FM mixer (Nippon Coke Industry Co., Ltd.).

Fine silica particles include dry silica or fumed silica produced by vapor phase oxidation of silicon halide, and wet silica produced from water glass. As the inorganic fine particles, a dry silica having a small amount of silanol groups on the surface and the inside of the silica fine particles and a small amount of Na ₂ O and (SO ₃ ) _2- is preferable. In addition, it may be composite fine particles of silica and other metal oxides, which are produced by using a metal halogen compound such as aluminum chloride, titanium chloride or the like together with a silicon halogen compound in the production process of dry silica.

  The use of inorganic particles whose surface is hydrophobized can achieve adjustment of the frictional charge of toner, improvement of environmental stability, and improvement of fluidity under high temperature and high humidity conditions. Because it is preferable. When the inorganic fine particles externally added to the toner absorb moisture, the triboelectric charge amount and the fluidity of the toner are reduced, and the developability and the transferability are easily reduced.

  As a treating agent for hydrophobizing inorganic fine particles, unmodified silicone varnish, various modified silicone varnish, unmodified silicone oil, various modified silicone oil, silane compound, silane coupling agent, other organosilicon compounds, and Organic titanium compounds are mentioned. Among them, silicone oil is preferred. These treating agents may be used alone or in combination.

  The total addition amount of the inorganic fine particles is preferably 1.0 to 5.0 parts by mass, and more preferably 1.0 to 2.5 parts by mass with respect to 100.0 parts by mass of the toner particles. The external additive preferably has a particle diameter of 1/10 or less of the average particle diameter of the toner particles from the viewpoint of durability when added to the toner.

  Next, an example of an image forming apparatus which can suitably use the toner of the present invention will be specifically described with reference to FIG. In FIG. 1, reference numeral 100 denotes a photosensitive drum, around which a primary charging roller 117, a developing device 140 having a developing sleeve 102, a transfer charging roller 114, a cleaner 116, a register roller 124 and the like are provided. The photosensitive drum 100 is charged to, for example, -600 V by the primary charging roller 117 (the applied voltage is, for example, AC voltage 1.85 kVpp, DC voltage -620 Vdc). Then, exposure is performed by irradiating the photosensitive member 100 with the laser light 123 by the laser generator 121, and an electrostatic latent image corresponding to a target image is formed. The electrostatic latent image on the photosensitive drum 100 is developed with a one-component toner by the developing device 140 to obtain a toner image, and the toner image is transferred onto the transfer material by the transfer roller 114 in contact with the photosensitive member via the transfer material. Be done. The transfer material carrying the toner image is conveyed to the fixing device 126 by the conveyance belt 125 or the like and fixed on the transfer material. Further, the toner left on the photosensitive member is partially cleaned by the cleaner 116.

  In addition, although the image forming apparatus of magnetic one component jumping development was shown here, it may be used for any method of jumping development or contact development.

  Hereinafter, methods of measuring various physical properties according to the present invention will be described.

<Method of calculating solubility parameter (SP value)>
The SP value in the present invention was determined using the following Fedors equation (4). Here, the values of Δei and Δvi refer to the evaporation energy and molar volume (25 ° C.) of atoms and groups according to “Basic science of coatings”, pp. 54-57, 1986 (槇). I made it.
δi = [Ev / V] ^1/2 = [Δei / Δvi] ^1/2 equation (4)
Ev: Evaporation energy V: Molar volume Δei: Evaporation energy of an atom or atomic group of component i Δvi: Molar volume of an atom or atomic group of component i For example, hexanediol is atomic group (-OH) x 2 + (-CH ₂₎ The calculated SP value is obtained by the following equation.
δi = [Δei / Δvi] ^1/2 = [{(5220) × 2 + (1180) × 6} / {(13) × 2 + (16.1) × 6}] ^1/2
From this, the SP value (δi) is 11.95.

<Measuring method of molecular weight>
The weight average molecular weight (Mw) of the crystalline polyester is measured by gel permeation chromatography (GPC) as follows.

First, the crystalline polyester is dissolved in tetrahydrofuran (THF) at room temperature. The resulting solution is filtered through a solvent-resistant membrane filter "Misholy Disc" (manufactured by Tosoh Corp.) having a pore diameter of 0.2 μm to obtain a sample solution. The sample solution is adjusted so that the concentration of the component soluble in THF is 0.8% by mass. It measures on condition of the following using this sample solution.
Device: High-speed GPC device "HLC-8220GPC" (manufactured by Tosoh Corporation)
Column: LF-604 double eluent: THF
Flow rate: 0.6 ml / min
Oven temperature: 40 ° C
Sample injection volume: 0.020 ml
In calculating the molecular weight of the sample, standard polystyrene resin (for example, trade name "TSK standard polystyrene F-850, F-450, F-288, F-128, F-80, F-40, F-20, F- 10, F-4, F-2, F-1, A-5000, A-2500, A-1000, A-500 ", Tosoh Co., Ltd. product) The molecular weight calibration curve created using is used.

  The molecular weight of the vinyl polymer moiety of the crystalline polyester is measured by hydrolyzing the polyester moiety of the crystalline polyester.

  Specifically, 5 ml of dioxane and 1 ml of a 10% by mass aqueous potassium hydroxide solution are added to 30 mg of crystalline polyester and shaken at a temperature of 70 ° C. for 6 hours to hydrolyze the polyester portion. The solution is then dried to make a sample for measurement of molecular weight of vinyl polymer sites. The subsequent operation is performed in the same manner as the measurement of the molecular weight of the crystalline polyester.

<Method of measuring melting point of crystalline polyester>
The melting point of the crystalline polyester is measured according to ASTM D3418-82 using a differential scanning calorimeter “Q1000” (manufactured by TA Instruments).

  The temperature correction of the device detection unit uses the melting points of indium and zinc, and the heat of fusion uses the heat of fusion of indium.

  Specifically, 5 mg of crystalline polyester is precisely weighed and placed in an aluminum pan, using an empty aluminum pan as a reference, with a temperature rising rate in the measurement temperature range of 30 to 200 ° C. Measure at 10 ° C / min. In the measurement, the temperature is once raised to 200 ° C., then the temperature is lowered to 30 ° C., and then the temperature is raised again. The maximum endothermic peak of the DSC curve in the temperature range of 30 to 200 ° C. in the second temperature rising process is taken as the melting point in the DSC measurement of the crystalline polyester of the present invention.

<Method for measuring the amount of carbon derived from a silane compound immobilized on the surface of a magnetic substance>
The magnetic material used for the magnetic toner of the present invention is surface-treated with a silane compound having a hydrocarbon group. Among the treated silane compounds, components not immobilized on the surface can be removed by washing with a solvent. Therefore, the amount of silane compound immobilized on the surface of the magnetic substance can be known by accurately measuring the amount of carbon contained in the magnetic substance after the washing treatment.

  First, the magnetic substance is washed with styrene. In a 50 ml glass vial, 20 g of styrene and 1.0 g of a magnetic substance are charged, and the glass vial is set in "KM Shaker" (model: V.SX) manufactured by Iwaki Sangyo Co., Ltd. Next, the processing agent contained in the surface-treated magnetic material is eluted in styrene by shaking for 1 hour with the speed set to 50. Thereafter, the magnetic substance and styrene are separated, and the magnetic substance is sufficiently dried by a vacuum dryer.

  The amount of carbon per unit weight of the dried magnetic substance is measured using a carbon / sulfur analyzer (EMIA-320V) manufactured by HORIBA. In the measurement, for example, the sample preparation amount at the time of EMIA-320 V measurement may be 0.20 g, and a mixture of tungsten and tin may be used as a flame retardant.

  In the present invention, the amount of carbon after washing is taken as the amount of carbon derived from the silane compound immobilized on the surface of the magnetic substance.

<Method of measuring weight average particle diameter (D4)>
The weight average particle diameter (D4) of the toner is calculated as follows. As a measuring apparatus, a precise particle size distribution measuring apparatus “Coulter Counter Multisizer 3” (registered trademark, manufactured by Beckman Coulter, Inc.) having a 100 μm aperture tube and using a pore electrical resistance method is used. The setting of measurement conditions and the analysis of measurement data use the attached special software "Beckman Coulter Multisizer 3 Version 3.51" (manufactured by Beckman Coulter, Inc.). The measurement is performed with 25,000 channels of effective measurement channels.

  As the electrolytic aqueous solution used for the measurement, a solution in which special grade sodium chloride is dissolved in ion exchange water so that the concentration is 1% by mass, for example, “ISOTON II” (manufactured by Beckman Coulter, Inc.) can be used.

  In addition, before performing measurement and analysis, the setting of the dedicated software is performed as follows.

  In the "Change Standard Measurement Method (SOM)" screen of the dedicated software, set the total count number in the control mode to 50000 particles, set the number of measurements once, and the Kd value "standard particle 10.0 μm" (Beckman Coulter Set the value obtained using The threshold and noise level are automatically set by pressing the "Threshold / noise level measurement button". Also, set the current to 1600 μA, the gain to 2, and the electrolyte to ISOTON II, and check “Aperture tube flush after measurement”.

  In the dedicated soft “pulse to particle size conversion setting” screen, the bin interval is set to logarithmic particle size, the particle size bin is set to 256 particle size bin, and the particle size range is set to 2 μm to 60 μm.

  The specific measurement method is as follows.

  (1) Put 200 ml of the electrolytic aqueous solution into a 250 ml round bottom beaker for Multisizer 3 dedicated to a glass, set it on a sample stand, and stir the stirrer rod at 24 rotations / second counterclockwise. Then, dirt and air bubbles in the aperture tube are removed by the "aperture flush" function of special software.

  (2) Into a 100 ml flat bottom beaker made of glass, 30 ml of the electrolytic aqueous solution is placed. Among them, “contaminone N” (nonionic surfactant, anionic surfactant, 10% by weight aqueous solution of neutral detergent for pH 7 precision measuring instrument cleaning consisting of organic builders as a dispersing agent, Wako Pure Chemical Industries, Ltd. 0.3 ml of a diluted solution obtained by diluting 3 times) with deionized water.

  (3) Two oscillators with an oscillation frequency of 50 kHz are built in with 180 degrees of phase shift, and an ultrasonic dispersion device “Ultrasonic Dispersion System Tetora 150” (manufactured by Nikkaki Bios Co., Ltd.) having an electrical output of 120 W is prepared. Put 3.3 l of ion exchange water into the water tank of the ultrasonic disperser, and add 2 ml of Contaminone N into this water tank.

  (4) The beaker of said (2) is set to the beaker fixing hole of the said ultrasonic dispersion device, and an ultrasonic dispersion device is operated. Then, the height position of the beaker is adjusted so that the resonance state of the liquid surface of the electrolytic aqueous solution in the beaker is maximized.

  (5) While the electrolytic aqueous solution in the beaker of (4) is irradiated with ultrasonic waves, 10 mg of toner is added little by little to the aqueous electrolytic solution and dispersed. Then, ultrasonic dispersion processing is continued for another 60 seconds. In addition, in ultrasonic dispersion, the water temperature of the water tank is appropriately adjusted so as to be 10 ° C. or more and 40 ° C. or less.

  (6) In the round bottom beaker of (1) placed in the sample stand, the aqueous electrolyte solution of (5) in which the toner is dispersed using a pipette is dropped to adjust the measurement concentration to 5%. Then, measurement is performed until the number of measurement particles reaches 50,000.

  (7) The measurement data is analyzed by the dedicated software attached to the device to calculate the weight average particle diameter (D4). The “average diameter” on the “analysis / volume statistical value (arithmetic mean)” screen when the graph / volume% is set in the dedicated software is the weight average particle diameter (D4).

  Hereinafter, the present invention will be more specifically described by way of examples. The present invention is not limited by the following examples. In addition, the number of parts and% of an Example and a comparative example are all mass references | standards unless there is particular notice.

<Production of Vinyl Polymer 1>
In a reaction vessel equipped with a stirrer, a thermometer, a nitrogen introducing pipe, and a pressure reducing device, 100.0 parts by mass of xylene was heated while replacing with nitrogen, and the solution was refluxed at a liquid temperature of 140 ° C. A mixture of 100.0 parts by mass of styrene and 10.0 parts by mass of Dimethyl-2,2'-azobis (2-methylpropionate) was added dropwise to the solution over 3 hours, and after completion of the addition, the solution was stirred for 3 hours . Thereafter, xylene and residual styrene were distilled off at 160 ° C. and 1 kPa to obtain a vinyl polymer 1. Mw of the vinyl polymer 1 was 6000.

<Production of Vinyl Polymer 3 >
A vinyl polymer 3 was obtained in the same manner as the vinyl polymer 1 except that the production conditions as shown in Table 1 were changed. Physical properties of the obtained vinyl polymer 3 are shown in Table 1.

<Production of crystalline polyester 1>
The following was charged into a reaction vessel equipped with a stirrer, a thermometer, a nitrogen introducing pipe, a dewatering pipe, and a pressure reducing device, and reacted at 160 ° C. for 5 hours under a nitrogen atmosphere.
・ Vinyl polymer 1 159.1 parts by mass ・ Xylene 127.3 parts by mass ・ 1,10-decanediol 105.3 parts by mass ・ Titanium (IV) isopropoxide 0.56 parts by mass Then, 100.0 parts by mass of sebacic acid Was added and reacted at 160 ° C. for 5 hours and at 180 ° C. for 4 hours. The mixture was further reacted at 180 ° C. and 1 kPa until desired Mw was obtained, to obtain a crystalline polyester 1 as a block polymer. Physical properties of the obtained crystalline polyester 1 are shown in Table 2.

<Production of crystalline polyesters 3 to 6, 9, 15 , 16 and 21>
Crystalline polyesters 3 to 6, 9, 15 , 15 , 16 and 21 were obtained in the same manner as in the production of crystalline polyester 1 except that the raw materials and production conditions shown in Table 2 were changed. Physical properties of the obtained crystalline polyesters 3 to 6, 9, 15 , 16 and 21 are shown in Table 2.

<Production of magnetic iron oxide>
55 liters of a 4.0 mol / L sodium hydroxide aqueous solution is mixed and stirred with 50 liters of an iron sulfate first aqueous solution containing 2.0 mol / L Fe ^2+, and a ferrous salt aqueous solution containing ferrous hydroxide colloid Obtained. The aqueous solution was maintained at 85 ° C., and oxidation reaction was carried out while blowing in air at 20 L / min to obtain a slurry containing core particles.

  The obtained slurry was filtered and washed with a filter press, and then the core particles were re-dispersed in water and reslurried. To this reslurry solution, 0.20 mass% of sodium silicate in terms of silicon is added per 100 parts of core particles to adjust the pH of the slurry solution to 6.0 and stir, thereby performing magnetic oxidation with a silicon-rich surface. Iron particles were obtained. The obtained slurry was filtered and washed with a filter press, and reslurry was further performed with ion exchanged water. Ion exchange resin SK110 (made by Mitsubishi Chemical) 500g (10 mass% with respect to magnetic iron oxide) was supplied to this reslurry liquid (50 g / L of solid content), and it stirred for 2 hours, and performed ion exchange. Thereafter, the ion exchange resin was removed by filtration through a mesh, filtered and washed with a filter press, dried and crushed to obtain magnetic iron oxide having a number average diameter of 0.23 μm.

<Production of Silane Compound 1>
30 parts of iso-butyltrimethoxysilane was added dropwise to 70 parts of ion-exchanged water with stirring. Thereafter, the aqueous solution was maintained at pH 5.5 and a temperature of 40 ° C., and dispersed using a disper wing for 120 minutes at a circumferential speed of 0.46 m / s to conduct hydrolysis. Thereafter, the pH of the aqueous solution was adjusted to 7.0 and cooled to 10 ° C. to stop the hydrolysis reaction. Thus, an aqueous solution containing silane compound 1 was obtained.

<Production of Silane Compound 2>
30 parts of iso-propyltrimethoxysilane was added dropwise to 70 parts of ion-exchanged water with stirring. Thereafter, the aqueous solution was maintained at pH 4.2 and a temperature of 25 ° C., and was dispersed for 60 minutes at a circumferential speed of 0.46 m / s using a disper wing to carry out hydrolysis. Thereafter, the pH of the aqueous solution was adjusted to 7.0 and cooled to 10 ° C. to stop the hydrolysis reaction. Thus, an aqueous solution containing the silane compound 2 was obtained.

<Production of Silane Compound 3>
30 parts of n-decyltrimethoxysilane was added dropwise to 70 parts of ion-exchanged water with stirring. Thereafter, the aqueous solution was maintained at a pH of 6.1 and a temperature of 53 ° C., and dispersed using a disper wing at a circumferential speed of 0.46 m / s for 360 minutes to conduct hydrolysis. Thereafter, the pH of the aqueous solution was adjusted to 7.0 and cooled to 10 ° C. to stop the hydrolysis reaction. Thus, an aqueous solution containing the silane compound 3 was obtained.

<Production of Silane Compound 4>
30 parts of n-hexyltrimethoxysilane was added dropwise to 70 parts of ion-exchanged water with stirring. Thereafter, the aqueous solution was maintained at pH 5.7 and a temperature of 45 ° C., and was dispersed for 180 minutes at a circumferential speed of 0.46 m / s using a disper wing to conduct hydrolysis. Thereafter, the pH of the aqueous solution was adjusted to 7.0 and cooled to 10 ° C. to stop the hydrolysis reaction. Thus, an aqueous solution containing the silane compound 4 was obtained.

<Production of Silane Compound 5>
30 parts of ethyltrimethoxysilane was added dropwise to 70 parts of ion-exchanged water with stirring. Thereafter, the aqueous solution was maintained at pH 3.3 and a temperature of 10 ° C., and was dispersed for 30 minutes at a circumferential speed of 0.46 m / s using a disper wing to carry out hydrolysis. After that, the hydrolysis reaction was stopped by setting the pH of the aqueous solution to 7.0. Thus, an aqueous solution containing the silane compound 5 was obtained.

<Manufacture of magnetic body 1>
One hundred parts of the magnetic iron oxide were placed in a high speed mixer (LFS-2 manufactured by Fukae Pautech Co., Ltd.), and silane compound 1 (8.0 parts) was dropped over 2 minutes while stirring at a rotational speed of 2000 rpm. Then, it was mixed and stirred for 5 minutes. Next, in order to increase the adhesion of the silane compound, it was dried at 40 ° C. for 1 hour, and after reducing the water content, the mixture was dried at 110 ° C. for 3 hours to allow the condensation reaction of the silane compound to proceed. Thereafter, it was crushed and passed through a sieve of 100 μm mesh to obtain a magnetic substance 1. Physical properties of the magnetic substance 1 are shown in Table 3 .

<Manufacture of magnetic materials 4 and 5 >
Magnetic materials 4 and 5 were obtained in the same manner as in the manufacture of the magnetic material 1 except that the silane compound used was changed as shown in Table 3 . Physical properties of the magnetic substances 4 and 5 are shown in Table 3 .

<Production of Magnetic Toner Particles 1>
After adding 450 parts of 0.1 mol / L Na ₃ PO ₄ aqueous solution to 720 parts of ion exchange water and heating to 60 ° C., 67.7 parts of 1.0 mol / L CaCl ₂ aqueous solution is added And an aqueous medium containing a dispersion stabilizer.

・ Styrene 79.0 parts ・ n-butyl acrylate 21.0 parts ・ Divinylbenzene 0.6 parts ・ Iron complex of monoazo dye (T-77: Hodogaya Chemical Co., Ltd.) 1.5 parts ・ Magnetic substance 1 90.0 parts · Amorphous saturated polyester resin 5.0 parts (Amorphous saturated polyester resin obtained by condensation reaction of ethylene oxide and propylene oxide adduct of bisphenol A with terephthalic acid; Mw = 9500, acid value = 2.2 mg KOH /) g, glass transition temperature = 68 ° C)
The above formulation was uniformly dispersed and mixed using an attritor (manufactured by Mitsui Miike Kako Co., Ltd.) to obtain a monomer composition. This monomer composition is heated to 63 ° C., 10 parts by mass of crystalline polyester 1 listed in Table 2 and 15 parts by mass of paraffin wax (HNP-9 manufactured by Nippon Seiwa Co., Ltd.) are added and mixed therein. It dissolved.

During the aqueous medium, a monomer composition obtained by dissolving the crystalline polyester 1 and paraffin wax were charged, 60 ° C., T. under N ₂ atmosphere K. The mixture was granulated by stirring with a homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) at 12000 rpm for 10 minutes. Then, while stirring with a paddle stirring blade, 6.0 parts by mass of a polymerization initiator t-butylperoxypivalate was added, and the temperature was raised to 70 ° C. to react for 4 hours. After completion of the reaction, the suspension was heated to 100 ° C. and maintained for 2 hours. Thereafter, as a cooling step, ice was added to the suspension, and the suspension was cooled from 100 ° C. to 50 ° C. at a rate of 40 ° C./min, and then allowed to cool to room temperature. Thereafter, hydrochloric acid is added to the suspension and the dispersion stabilizer is dissolved by sufficient washing, and the resultant is filtered and dried to obtain magnetic toner particles 1. The preparation method and formulation are shown in Table 4 .

<Production of Magnetic Toner Particles 3-6 , 10 , 20 , 21 , 27 >
As shown in Table 4 , the materials and the number of added parts are changed, and the amount of the dispersion stabilizer is adjusted so that the weight average particle diameter (D4) becomes 6.0 to 9.0 μm. Magnetic toner particles 3 to 6 , 10 , 20 , 21 and 27 were obtained in the same manner as in production. Physical properties of the obtained magnetic toner particles are shown in Table 4 .

<Production of Magnetic Toner Particles 29>
The following materials were mixed in advance, melt-kneaded using a twin screw extruder, and the cooled kneaded product was roughly crushed using a hammer mill, and the obtained finely pulverized product was classified to obtain magnetic toner particles 29.
Crystalline polyester 1 100.0 parts by mass Magnetic body 1 100.0 parts by mass Iron complex of monoazo dye (T-77: manufactured by Hodogaya Chemical Co., Ltd.) 1.5 parts by mass Paraffin wax (manufactured by Nippon Seiwa Co., Ltd.) HNP-9) 5.0 parts by mass The physical properties of the magnetic toner particles 29 are shown in Table 4 .

< Production of Magnetic Toner 1 , 3 to 6 , 10 , Comparative Magnetic Toner 1 , 2, 8, 10>
100 parts by mass of magnetic toner particles 1 and 0.8 parts by mass of hydrophobic silica fine powder prepared by subjecting dry silica fine particles (primary particle diameter: 8 nm) having a BET specific surface area of 300 m ² / g (primary particle diameter: 8 nm) to hexamethyldisilazane treatment The magnetic toner 1 was obtained by mixing using a Henschel mixer (manufactured by Mitsui Miike Kako Co., Ltd.).

Also, except that the magnetic toner particles 1 are changed to the magnetic toner particles 3 to 6 , 10 , 20 , 21 and 27 , similarly, the magnetic toners 3 to 6 and 10 and the comparison magnetic toners 1 to 8 are used. I got All of the obtained magnetic toners had a weight average particle diameter (D4) of 6.0 to 9.0 μm, and in DSC measurement, an endothermic peak derived from a crystalline polyester was observed.

Examples 1 , 3 to 6 , 10, Comparative Examples 1 , 2, 8, 10>
The following evaluations were performed using the obtained toners 1 , 3 to 6 , 10 and the magnetic toners 1 , 2, 8, 10 for comparison. The evaluation results are shown in Table 5 .

[Initial developability]
As the image forming apparatus, LBP 3410 (monochrome laser beam printer, manufactured by Canon Inc.) equipped with a cartridge for LP 3410 filled with toner was used. In the evaluation of the initial developability, an image forming apparatus was left for 1 day in a normal temperature and normal humidity environment (temperature 23 ° C. and humidity 60%). As the recording paper, A4 color laser copying paper (manufactured by Canon Inc., 80 g / m ² ) was used.

Five solid images were continuously output under a normal temperature and normal humidity environment, and the image density of the obtained five solid images was measured using a Macbeth reflection densitometer (manufactured by Macbeth). The worst values of these were taken as the solid density, and the higher the solid density, the better the developability was evaluated. The evaluation results are described in Table 5 .

Fixability
As an image forming apparatus, LBP 3410 equipped with a cartridge for LP 3410 filled with toner was used. In addition, it was remodeled to enable development bias adjustment. In the evaluation of the fixability, the image forming apparatus was left for one day in a low temperature and low humidity environment (temperature 15 ° C. humidity 10%). The low temperature and low humidity environment is a more severe environment for fixing since the toner becomes cold. As a recording paper, FOX RIVER BOND paper (110 g / m ² ) which was left for 1 day in a low temperature and low humidity environment was used. This recording paper is a thick paper with relatively large surface irregularities, and is a severe paper in the evaluation of the rubbing of the printed image. The evaluation procedure is shown below.

First, a solid image was printed under a low temperature and low humidity environment using an image forming apparatus which was left under a low temperature and low humidity environment. The image density of the obtained solid image was measured using a Macbeth reflection densitometer (manufactured by Macbeth), and then the developing bias was adjusted so that the image density was 1.4 or more and 1.45 or less. Further, after standing for 1 hour in a low temperature and low humidity environment, one solid image was output with the adjusted bias setting. A weight of 55 g / cm ² was applied to silbon paper, and the obtained solid image was rubbed twice. The solid image after rubbing and the silbon paper used for rubbing were visually observed and evaluated according to the following criteria.
A: Even after rubbing, the uniformity of the image density is maintained.
B: Even after rubbing, the uniformity of the image density is maintained, but the silbon paper is slightly soiled.
C: Even after rubbing, the uniformity of the image density is maintained, but there is a clear stain on the silbon paper.
D: In the solid image after rubbing, there is a portion (non-uniform portion) where the density is low enough to be recognized when held over light.
E: A low density portion is clearly seen in the solid image after rubbing.

[Transferability evaluation]
As an image forming apparatus, LBP 3410 equipped with a cartridge for LP 3410 filled with toner was used. In the evaluation of the transferability, the image forming apparatus was left for one day under a high temperature and high humidity environment (temperature 32.5 ° C. and humidity 82.5%). A high temperature and high humidity environment is a more severe environment for transfer, since the paper contains a large amount of water, so transfer bias is less likely to occur, and transfer failure tends to occur. Further, as the recording paper, A4 color laser copying paper (manufactured by Canon Inc., 80 g / m ² ) which was left for a day under high humidity and high temperature environment was used.

  Five solid black images are output by the above-mentioned image forming apparatus, and they are ranked visually according to the following evaluation criteria, and for the part where density thinning occurs due to transfer failure, the density of ungenerated part and generated part by Macbeth reflection densitometer The differences were compared.

Thereafter, 15000 sheets of horizontal line images with a printing rate of 1% were outputted in the intermittent mode, and the above-mentioned transferability was evaluated again. When the magnetic toner is subjected to durability evaluation, there is a bias in the toner consumed at the time of development because there is a difference between particles regarding the dispersion state of the magnetic material. According to the study of the present inventors, after the endurance, since the non-uniform distribution of the magnetic substance in the toner particles (aggregation and the like in the particles is observed) tends to remain, the transferability after the endurance should be observed. The dispersion state of the magnetic material as described above can be strictly evaluated.
A: All five uniform solid images were obtained, and no transfer failure was observed.
B: A slight portion of the missing transfer (difference in density of 0.1 or less) is observed in one of five sheets.
C: In 2 to 5 out of 5 sheets, slight transfer omission (density difference 0.1 or less) part is observed, but no transfer omission exceeding the density difference 0.1 has occurred.
D: A slight transfer omission (density difference of 0.1 or less) portion is observed in six or more places out of five sheets, but no transfer omission exceeding a density difference of 0.1 has occurred.
E: A transfer loss exceeding a density difference of 0.1 has occurred.

Claims (8)

A magnetic toner having magnetic toner particles comprising a binder resin, crystalline polyester and a magnetic material,
The binder resin contains 70% by mass or more of a styrene acrylic resin based on the mass of the binder resin,
The crystalline polyester is
i) The melting point (Tm) is 55 ° C. or more and 90 ° C. or less,
ii) having polyester moieties and vinyl polymer moieties,
ii-1) the polyester moiety has a unit represented by the following formula (1),
ii-2) the weight average molecular weight (Mw) of the vinyl polymer moiety is 3,000 or more and 40000 or less,
A silane compound having a partial structure represented by the following formula (2) is immobilized and present on the surface of the magnetic substance,
The difference between the solubility parameter of the partial structure represented by the solubility parameter and the lower following formula units represented by the following following formula (1) (2) is 0.80 to 1.20,
Magnetic toner characterized by

(In formula (1) , m is an integer of 4-14, n represents the integer of 6-16.)

(In formula (2) , R represents a hydrocarbon group having 3 or more carbon atoms.) Wherein the polyester portion percentage relative to the weight of the vinyl polymer moiety (Polyester site / vinyl polymer moiety) is 40 / 60-95 / 5, the magnetic toner according to claim 1. The immobilized on the surface of the magnetic material, the amount of carbon derived from the silane compound is from 0.35 to 0.60 wt% of a magnetic substance basis, magnetic toner according to claim 1 or 2. The content of the magnetic material, said Ri binder resin 100 parts by those other, it is from 30.0 to 80.0 parts by weight, the magnetic toner according to any one of claims 1 to 3. The content of the crystalline polyester and the magnetic body, based on the weight,
Magnetic substance / Crystalline polyester = 95/5 to 75/25
The magnetic toner according to any one of claims 1 to 4, wherein The magnetic toner according to any one of claims 1 to 5, wherein the crystalline polyester is a block polymer. The content of the crystalline polyester, Ri 100 parts by weight of the binder resin person other, is from 2.0 to 40.0 parts by weight, the magnetic toner according to any one of claims 1-6. The melting point (Tm) is 56 ° C. or more and 82 ° C. or less, the weight average molecular weight (Mw) of the vinyl polymer portion is 4000 or more and 6000 or less, and the solubility parameter of the unit represented by the formula (1) and the formula The difference with the solubility parameter of the partial structure shown by (2) is 0.860 or more and 1.180 or less, and said R is a C4 or more and 10 or less hydrocarbon group. Magnetic toner according to item 1.

Images