JP2008304724A - Magnetic toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic toner which causes no electrostatic offset, excels in environmental stability and can obtain a high-density clear image with no ghost. <P>SOLUTION: The magnetic toner contains at least a binder resin and magnetic powder, wherein when the magnetic toner is dispersed in methanol, a supernatant liquid after the dispersion has an electric conductivity of 2.0-15.0 μS/cm. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a magnetic toner used in a recording method using an electrophotographic method, an electrostatic recording method, a magnetic recording method, a toner jet method, or the like.

  Many methods are known as electrophotographic methods. In general, an electrostatic latent image is formed on an electrostatic charge image carrier (hereinafter also referred to as “photoconductor”) by using a photoconductive substance 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. Is what you get. Examples of such an image forming apparatus include a copying machine and a printer.

  These printers and copiers have recently moved from analog to digital, and there is a strong demand for stable images regardless of the environment as well as excellent reproducibility of latent images and high resolution.

  Regarding the environmental stability, a toner has been proposed in which the electrical conductivity of an aqueous solution obtained by adding and stirring the toner in water is from 1 to 100 μS / cm, and can be stored for a long time in a high-temperature and high-humidity environment. It has been reported that excellent chargeability can be obtained (see Patent Document 1).

  Furthermore, many proposals have been made that define the electrical conductivity of the extract extracted with water (see Patent Documents 2 to 6), and there are few environmental differences and good chargeability and transferability can be obtained.

  However, although these toners improve the difference in toner charge amount depending on the environment, the phenomenon of uneven density called sleeve ghost cannot be solved sufficiently. A sleeve ghost is an image in which a halftone image portion is formed after a striped image portion of a black portion of a solid black image and a white portion of a solid white image. This is a phenomenon in which an afterimage of a portion appears with a low image density or an increased image density. This is because the charge amount of the toner supplied after the solid black development is different from the charge amount of the toner in the non-development portion (solid white portion), or the toner conveyance amount on the developing sleeve after the solid black development is the solid white portion. This occurs when the toner transport amount is different.

  Furthermore, in recent years, there has been a strong demand for speeding up and downsizing of copiers and printers, and a fixing unit that does not use a cleaning member has become necessary. However, when charged toner enters the roller of the fixing unit, it receives an electric field opposite to the toner holding force in the direction of the transfer material due to, for example, charge-up due to friction of the pressure roller, thereby The toner image is transferred to the fixing film (roller) side. There arises a problem of electrostatic offset, in which it is fixed on the transfer material again after one turn on the film (roller). There was room for improvement with respect to this electrostatic offset.

JP-A-7-319205 Japanese Patent Laid-Open No. 10-319624 JP 11-72949 A JP-A-11-84732 JP 2000-172007 A JP 2001-215749 A

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide a toner that is excellent in environmental stability and can obtain a clear image having a high density and no ghost. Another object of the present invention is to provide a toner that hardly causes electrostatic offset.

  As a result of diligent studies to solve the above problems, it is possible to stabilize the environment by dispersing the toner in methanol and stirring for 30 minutes so that the electrical conductivity of the supernatant liquid is 2.0 μS / cm or more and 15.0 μS / cm or less. The present inventors have found that a high-definition image that is excellent in properties and free from ghosting and scattering can be obtained.

  That is, according to the present invention, in a magnetic toner having at least a binder resin and magnetic powder, the magnetic toner is dispersed in methanol, and the electric conductivity of the supernatant after dispersion is 2.0 μS / cm or more and 15.0 μS / cm. The magnetic toner is characterized by the following.

  According to the present invention, it is possible to provide a toner that does not cause electrostatic offset, has excellent environmental stability, and can obtain a clear image having a high density and no ghost.

  As a result of the study by the present inventors, the magnetic toner is dispersed in methanol, and the electric conductivity of the supernatant after dispersion is 2.0 μS / cm or more and 15.0 μS / cm or less, more preferably 2.0 μS / cm or more and 10 or more. It was found that the sleeve ghost can be suppressed by setting the value to 0.0 μS / cm or less. For this reason, the present inventors consider as follows.

  First, by setting the electric conductivity of the supernatant after dispersing the magnetic toner in methanol to 2.0 μS / cm or more and 15.0 μS / cm or less, the toner charge rises very quickly, and after solid black development Even the supplied toner can have the same chargeability as the solid white toner.

  In order to improve the chargeability of the toner, as described in Patent Documents 1 to 6, it is important to suppress the amount of an ionic substance on the surface of the toner. Although possible, it has been difficult to improve the rising of the charge. This is because in the extract extracted with water, only the component dissolved in water can be measured, and the abundance of the low molecular weight compound having polarity present on the toner surface could not be monitored.

  Therefore, the present inventors dispersed the magnetic toner in methanol for 30 minutes, and examined the relationship between the electrical conductivity of the dispersed liquid after extraction (hereinafter abbreviated as methanol liquid) and the rising of the toner charge. It was found that the toner having a lower electrical conductivity of the methanol extract has a faster charge rise and becomes uniform. Therefore, it is important that the electrical conductivity of the methanol extract is 15.0 μS / cm or less.

  On the other hand, when the electric conductivity of the methanol extract is lower than 2.0 μS / cm, it quickly rises up in a high temperature and high humidity environment, but is easily charged up in a low temperature and low humidity environment. For this reason, a charge amount difference is generated between the solid white portion and the solid black portion, and a ghost is also generated in this case.

  Further, the fact that the electric conductivity of the methanol extract is 2.0 μS / cm or more and 15.0 μS / cm or less means that there is almost no low molecular weight compound having a polarity that prevents charging on the toner surface. In addition, the toner charge amount distribution becomes sharp, particles having a polarity opposite to that of the toner (reversal component) are less likely to be generated, and the toner is less likely to electrostatically aggregate. For this reason, good fluidity can be obtained in the developing device, particularly at the site where the developing sleeve takes in the toner, and the amount of toner transported on the developing sleeve can be stabilized even during development.

  As described above, ghosts are generated even in a high-temperature and high-humidity environment or a low-temperature and low-humidity environment due to the effect that the toner charge rises quickly and uniformly, and the toner is less likely to electrostatically aggregate and the toner conveyance amount on the developing sleeve is stable. Does not occur.

  In the present invention, the electrical conductivity of the methanol extract can be adjusted by the constituent components of the toner, ions present on the toner surface, and the like.

  Moreover, the electrical conductivity of the methanol extract in the present invention is defined as a value obtained by subtracting the electrical conductivity of methanol from the electrical conductivity of the methanol extract.

  The toner of the present invention preferably has a weight average particle diameter (D4) of 3 μm or more and 12 μm or less in order to faithfully develop finer latent image dots in order to achieve high image quality. 4 μm or more and 9 μm or less. When the weight average particle diameter (D4) is less than 3 μm, fluidity and agitation as a powder are lowered, and it becomes difficult to uniformly charge individual toner particles. On the other hand, when the weight average particle diameter (D4) is larger than 12 μm, the fog suppression is improved, but the dot reproducibility is lowered, which is not preferable.

  The magnetic toner of the present invention preferably has an average circularity of 0.950 or more. When the average circularity of the toner is 0.950 or more, the shape of the toner is spherical or close to it, and it is easy to obtain a uniform triboelectric chargeability with excellent fluidity, further improving ghost and electrostatic offset suppression. In the circularity distribution of the toner, when the mode circularity is 0.98 or more, the above action becomes more remarkable, which is more preferable.

  The magnetic toner of the present invention has a tetrahydrofuran (THF) insoluble content of a resin component, and the tetrahydrofuran insoluble content is 5.0 to 50.0 parts by mass (5.0 to 50% by mass with respect to 100 parts by mass of the resin component). 0.0 mass% or less). Due to the presence of tetrahydrofuran-insoluble matter in the magnetic toner, the strength of the magnetic toner is increased, toner deterioration is unlikely to occur during long-term use in a high-temperature environment, and a high-definition image without ghosting can be obtained even during long-term use. .

  In addition, the toner melts due to the heat received from the fixing device at the time of fixing. However, having a tetrahydrofuran insoluble content of 5.0% by mass or more and 50.0% by mass or less makes it possible to have appropriate viscoelasticity even at the time of melting. . For this reason, toner adhesion to a fixing member (for example, a film) hardly occurs even during fixing, which is preferable.

  Furthermore, since the toner of the present invention has a uniform and high charge amount as described above, it is more difficult to adhere to the fixing film (or roller) due to electrostatic repulsion. Thus, electrostatic offset is greatly improved by the synergistic effect of having an appropriate viscoelasticity at the time of melting and having a uniform and high charge amount.

  The THF-insoluble matter in the resin component of the magnetic toner can be measured as follows.

1 g of magnetic toner is precisely weighed and charged on a cylindrical filter paper, and Soxhlet extracted with 200 ml of THF for 20 hours. Thereafter, the cylindrical filter paper is taken out, vacuum-dried at 40 ° C. for 20 hours, the residue mass is measured, and calculated from the following formula. The resin component of the magnetic toner is a component obtained by removing the magnetic powder, the charge control agent, the release agent component, the external additive, and the pigment from the magnetic toner. At the time of measuring the THF-insoluble content, the THF-insoluble content based on the resin component is calculated in consideration of whether these contents are soluble or insoluble in THF.
THF insoluble content (%) = (W2-W3) / (W1-W3-W4) × 100

  Here, W1 is the mass of the magnetic toner, W2 is the mass of the residue, W3 is the mass of a component insoluble in THF other than the resin component of the magnetic toner, and W4 is the mass of a component soluble in THF other than the resin component of the magnetic toner. is there.

  The THF-insoluble content of the resin component of the magnetic toner can be arbitrarily changed depending on the combination of the initiator used, the type and amount of the crosslinking agent, and the like. It can also be adjusted by using a chain transfer agent or the like.

The magnetic toner of the present invention preferably has a residual magnetization of 2.0 Am ² / kg (emu / g) or less when magnetized with a magnetic field of 79.6 kA / m (1000 oersted), more preferably 1.7 Am. ² / kg (emu / g) or less. The magnetic toner is repeatedly taken into and discharged from the developing sleeve in the developing device, and circulates in the toner container. Here, when the residual magnetization of the toner is low, the toner circulating in the toner container is hard to be magnetically aggregated and can maintain good fluidity. In addition, since the magnetic toner of the present invention does not easily cause electrostatic aggregation as described above, it is possible to obtain very good fluidity, the toner conveyance amount on the developing sleeve is more stable, and the ghost is used even for long-term use. Improves. Therefore, in the present invention, the residual magnetization of the magnetic toner is preferably 2.0 Am ² / kg (emu / g) or less, and more preferably 1.7 Am ² / kg (emu / g). The residual magnetization of the magnetic toner of the present invention can be arbitrarily changed depending on the amount of magnetic substance contained and the residual magnetization of the magnetic substance.

In the present invention, the magnetization strength of the toner in a magnetic field of 79.6 kA / m (1000 oersted) is preferably 26.0 Am ² / kg or more and 31.0 Am ² / kg (emu / g) or less. When the magnetization strength of the toner is less than 26.0 Am ² / kg, the rising of the toner on the developing sleeve becomes unstable, and an increase in fog and image density due to the fact that the toner cannot be uniformly charged. Unevenness is caused and ghost is easily generated, which is not preferable. On the other hand, if the magnetization strength of the toner is greater than 31.0 Am ² / kg, the fog is improved, but the developing property is lowered, and the toner deteriorates significantly in long-term use. The magnetization intensity of the toner can be arbitrarily changed according to the amount of the magnetic substance contained and the magnetization intensity of the magnetic substance.

  In the present invention, the residual magnetization and the strength of magnetization of the magnetic toner are measured using an oscillating magnetometer VSM P-1-10 (manufactured by Toei Kogyo Co., Ltd.) at an external magnetic field of 79.6 kA / Measure in m. This is because the measurement is performed at a magnetic field of 79.6 kA / m (1000 oersted) because the maximum magnetic force on the developing sleeve is 700 to 1000 oersted.

The magnetic powder used in the toner of the present invention is mainly composed of magnetic iron oxide such as triiron tetroxide and γ-iron oxide, and is composed of phosphorus, cobalt, nickel, copper, magnesium, manganese, aluminum, silicon, and the like. An element such as may be included. These magnetic powders preferably have a BET specific surface area of 2 or more and 30 m ² / g or less, more preferably 3 or more and 28 m ² / g or less by a nitrogen adsorption method. Further, those having a Mohs hardness of 5 or more and 7 or less are preferable. The shape of the magnetic powder includes polyhedron, octahedron, hexahedron, spherical shape, needle shape, scale shape, etc., but those having low anisotropy such as polyhedron, octahedron, hexahedron, spherical shape, etc. It is preferable in terms of enhancement.

  The magnetic powder preferably has a volume average particle size of 0.10 μm or more and 0.40 μm or less. In general, the smaller the particle size of the magnetic powder, the higher the coloring power, but the magnetic powder tends to aggregate, and the uniform dispersibility of the magnetic powder in the toner is inferior. In addition, when the volume average particle size is less than 0.10 μm, the magnetic powder itself becomes reddish black, so that it becomes a reddish conspicuous image particularly in a halftone image, which is not preferable because it is not a high-quality image. . On the other hand, when the volume average particle diameter exceeds 0.40 μm, the coloring power of the toner is insufficient, and in the suspension polymerization method (described later), which is a preferable method for producing the toner of the present invention, uniform dispersion becomes difficult.

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

  The magnetic powder used for the toner of the present invention can be produced, for example, by the following method. An aqueous solution containing ferrous hydroxide is prepared by adding an alkali such as sodium hydroxide in an amount equivalent to or greater than the iron component to the ferrous salt aqueous solution. Air was blown in while maintaining the pH of the prepared aqueous solution at 7 or higher, and ferrous hydroxide was oxidized while the aqueous solution was heated to 70 ° C. or higher. First, seed crystals serving as the core of the magnetic iron oxide powder were formed. Generate.

  Next, an aqueous solution containing about 1 equivalent of ferrous sulfate is added to the slurry-like liquid containing seed crystals based on the amount of alkali added previously. While maintaining the pH of the solution at 5 or more and 10 or less, air is blown to promote the reaction of ferrous hydroxide, and the magnetic iron oxide powder is grown with the seed crystal as the core. At this time, it is possible to control the shape and magnetic properties of the magnetic powder by selecting an arbitrary pH, reaction temperature, and stirring conditions. As the oxidation reaction proceeds, the pH of the liquid shifts to the acidic side, but the pH of the liquid is preferably not less than 5. A magnetic powder can be obtained by filtering, washing, and drying the magnetic material thus obtained by a conventional method.

  In the present invention, when the toner is produced in an aqueous medium, it is very preferable to hydrophobize the surface of the magnetic powder. When hydrophobizing by dry process, the washed, filtered and dried magnetic powder is hydrophobized. When the hydrophobization treatment is performed in a wet manner, after the oxidation reaction is completed, the dried material is redispersed, or after the oxidation reaction is completed, the iron oxide body obtained by washing and filtering is not dried and another aqueous medium is used. It is re-dispersed in it, and the re-dispersed liquid is hydrophobized while stirring sufficiently. Among these, from the viewpoint of performing a uniform surface treatment, it is preferable to perform a hydrophobization treatment after completion of the oxidation reaction, by reslurry as it is without drying after filtration and washing.

  To wet the surface treatment of the magnetic powder, that is, to hydrophobize the magnetic powder in an aqueous medium, first, sufficiently disperse the magnetic powder in the aqueous medium so as to have a primary particle size, and do not settle or agglomerate. Stir with a stirring blade or the like. Next, an arbitrary amount of the treatment agent is added to the above dispersion, and the surface treatment is performed while hydrolysis. At this time, the surface treatment is performed while sufficiently dispersing so as not to aggregate while using a device such as a pin mill or a line mill while stirring. It is more preferable to carry out.

  Here, the aqueous medium is a medium containing water as a main component. Specific examples include water itself, water added with a small amount of surfactant, water added with a pH adjuster, and water added with an organic solvent. As the surfactant, nonionic surfactants such as polyvinyl alcohol are preferable. The surfactant is preferably added in an amount of 0.1 to 5.0 mass% with respect to water. Examples of the pH adjuster include inorganic acids such as hydrochloric acid. Examples of the organic solvent include alcohols.

Examples of the treating agent that can be used in the surface treatment of the magnetic powder in the present invention include a silane coupling agent and a titanium coupling agent. More preferably used is a silane coupling agent, which is represented by the general formula (I).
R _m SiY _n (I)
[Wherein, 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, or a (meth) acryl group, and n represents 1 to 3 The following integers are shown. However, m + n = 4. ]

  Examples of the silane compound represented by the general formula (I) include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, β- (3,4 epoxycyclohexyl) ethyltrimethoxysilane, γ- Glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltri Acetoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiet Sisilane, n-butyltrimethoxysilane, isobutyltrimethoxysilane, trimethylmethoxysilane, n-hexyltrimethoxysilane, n-octyltrimethoxysilane, n-octyltriethoxysilane, n-decyltrimethoxysilane, hydroxypropyltrimethoxy Examples thereof include silane, n-hexadecyltrimethoxysilane, and n-octadecyltrimethoxysilane.

Among these, from the viewpoint of imparting high hydrophobicity to the magnetic powder, it is preferable to use an alkyltrialkoxysilane represented by the following general formula (II).
_{C p H 2p + 1 -Si- (} OC q H 2q + 1) 3 (II)
[Wherein, p represents an integer of 2 or more and 20 or less, and q represents an integer of 1 or more and 3 or less. ]

  When p in the above formula is smaller than 2, it is difficult to sufficiently impart hydrophobicity to the magnetic powder, and when p is larger than 20, hydrophobicity is sufficient. It is unfavorable because it increases. Furthermore, when q is larger than 3, the reactivity of silane is lowered and hydrophobicity is not sufficiently performed. Therefore, p in the formula is an integer of 2 or more and 20 or less (more preferably, an integer of 3 or more and 15 or less). It is preferable to use an alkyltrialkoxysilane in which q represents an integer of 1 or more and 3 or less (more preferably, an integer of 1 or 2).

  When the silane compound is used, it can be treated alone or in combination of a plurality of types. When using several types together, you may process separately with each silane compound, and may process simultaneously.

  The total amount of the treatment agent used is preferably 0.9 to 3.0 parts by mass with respect to 100 parts by mass of the magnetic powder, and the treatment agent depends on the surface area of the magnetic powder, the reactivity of the treatment agent, and the like. It is important to adjust the amount.

The magnetic powder used in the magnetic toner of the present invention is hydrophobized with a treatment agent, and the treatment agent desorption rate obtained by the following formula (1) is preferably 3% or more and 30% or less, More preferably, it is 3% or more and 20% or less.
Desorption rate = {1- (Amount of treatment agent contained in magnetic powder after being dispersed in toluene for 60 minutes) / (Amount of treatment agent contained in magnetic powder)} × 100 (1) )

  The desorption rate indicates the ratio of the treatment agent eluted from the magnetic powder. A large value means that there is a large amount of free treatment agent (treatment agent not chemically bonded to the magnetic powder). When the toner is produced, for example, when the toner is produced by a suspension polymerization method suitable for the present invention, the free processing agent is more likely to be unevenly distributed on the toner surface because it is more hydrophilic than other toner materials. For this reason, the electric conductivity of the methanol extract of the magnetic toner tends to increase, and it is preferable that the amount of free treatment agent is small.

  On the other hand, when the amount of the treatment agent eluted from the magnetic powder is small or extremely small, the hydrophobic treatment of the magnetic powder is often insufficient, the degree of hydrophobicity of the magnetic powder is lowered, and the toner charge amount is reduced. Decreasing is not preferable. In addition, when such a magnetic powder is used, the dispersibility of the magnetic powder also deteriorates, resulting in an increase in fog.

  Therefore, in this invention, it is preferable that the removal rate of the processing agent of a magnetic powder is 3.0% or more and 30.0% or less, More preferably, it is 3.0% or more and 20.0% or less.

  In the present invention, the desorption rate of the treatment agent can be arbitrarily determined depending on the treatment agent treatment conditions (amount, temperature, pH) at the time of magnetic powder production, treatment time, cleaning method of the surface-treated magnetic powder, and drying method. It is possible to change.

  In the present invention, other colorants may be used in combination with the magnetic powder. Examples of the colorant that can be used in combination include magnetic or nonmagnetic inorganic compounds and known dyes and pigments. Specifically, for example, ferromagnetic metal particles such as cobalt and nickel, or alloys obtained by adding chromium, manganese, copper, zinc, aluminum and rare earth elements to these, particles such as hematite, titanium black, nigrosine dye / pigment , Carbon black, phthalocyanine and the like. These are also preferably used by treating the surface.

  The glass transition temperature (Tg) of the toner of the present invention is preferably 40 ° C. or higher and 70 ° C. or lower. When the glass transition temperature is less than 40 ° C., the storage stability is lowered, and the toner is liable to deteriorate during long-term use. Therefore, considering the balance between fixability, storage stability, and developability, the glass transition temperature of the toner is preferably 40 ° C. or higher and 70 ° C. or lower. For example, the glass transition point of the toner is measured with a differential scanning calorimeter, and the measurement method is performed according to ASTM D 3418-99. In the measurement, the DSC curve is measured when the sample is heated once and the history is taken, then rapidly cooled, and again heated at a rate of temperature increase of 10 ° C./min and a temperature of 30 to 200 ° C.

  The magnetic toner of the present invention preferably has a core-shell structure in order to make the charge amount distribution more uniform and to prevent ghost and electrostatic offset. Specific methods for forming the shell include embedding the fine particles for the shell in the core particles, or attaching the ultra fine particles for the shell to the core particles when the toner is produced in an aqueous medium which is a preferred production method of the present invention. The shell layer can be formed by drying and drying. In addition, in the suspension suspension method and suspension polymerization method, the acid value and hydrophilicity of the high molecular weight polymer for the shell are utilized to make the shell unevenly distributed at the interface with water, that is, near the toner surface. Is possible. Furthermore, a shell can be formed by swelling a monomer on the surface of the core particle by a so-called seed polymerization method and polymerizing the monomer.

  Examples of the high molecular weight material for the shell layer include styrene such as polystyrene and polyvinyltoluene, and homopolymers of substituted styrene; styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, Styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-dimethylaminoethyl acrylate copolymer, styrene-meta Methyl acrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-dimethylaminoethyl methacrylate copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl Ethyl ether copolymer, styrene Styrene copolymers such as vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer; polymethyl methacrylate, poly Butyl methacrylate, polyvinyl acetate, polyethylene, polypropylene, polyvinyl butyral, silicone resin, polyester resin, styrene-polyester copolymer, poly (meth) acrylate-polyester copolymer, polyamide resin, epoxy resin, polyacrylic acid resin, terpene There exist resin, a phenol resin, etc., These can be used individually or in mixture of 2 or more types. Moreover, you may introduce | transduce functional groups, such as an amino group, a carboxyl group, a hydroxyl group, a sulfonic acid group, a glycidyl group, a nitrile group, in these polymers.

  The amount of these resins added is 0.5 to 20.0 parts by mass with respect to 100 parts by mass of the core particles, and 100 parts by mass of the polymerizable monomer in the suspension polymerization method which is a production method suitable for the present invention. 1.0 to 20.0 parts by mass is preferable. If the addition amount of the polyester resin is less than the above, a sufficient addition effect cannot be obtained, and if the addition amount is more than the above, it becomes difficult to design various physical properties of the toner.

  Among these resins, polyester is particularly preferable because the above effect is greatly expressed. As the polyester resin used in the present invention, a saturated polyester resin, an unsaturated polyester resin, or both can be appropriately selected and used.

  As the polyester resin used in the present invention, a normal resin composed of an alcohol component and an acid component can be used, and both components are exemplified below.

  As alcohol components, ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexane Diol, neopentyl glycol, 2-ethyl-1,3-hexanediol, cyclohexanedimethanol, butenediol, octenediol, cyclohexenedimethanol, hydrogenated bisphenol A, and bisphenol derivatives represented by formula (I);

［式中、Ｒはエチレンまたはプロピレン基であり、ｘ，ｙはそれぞれ１以上の整数であり、かつｘ＋ｙの平均値は２以上１０以下である。］

[Wherein, R is an ethylene or propylene group, x and y are each an integer of 1 or more, and the average value of x + y is 2 or more and 10 or less. ]

  Or hydrogenated compound of formula (I), or diol of formula (II);

あるいは式（ＩＩ）の化合物の水添物のジオールが挙げられる。

Or the diol of the hydrogenated compound of the compound of a formula (II) is mentioned.

  As the divalent carboxylic acid, benzene dicarboxylic acid such as phthalic acid, terephthalic acid, isophthalic acid, phthalic anhydride or the anhydride thereof; alkyl dicarboxylic acid such as succinic acid, adipic acid, sebacic acid, azelaic acid or the anhydride, Furthermore, succinic acid substituted with an alkyl or alkenyl group having 6 to 18 carbon atoms or an anhydride thereof; unsaturated dicarboxylic acid such as fumaric acid, maleic acid, citraconic acid, itaconic acid, or an anhydride thereof.

  In addition, polyhydric alcohols such as glycerin, pentaerythritol, sorbit, sorbitan, and oxyalkylene ethers of novolac type phenol resins can be cited as the alcohol component, and trimellitic acid, pyromellitic acid, 1,2,3,4- Examples thereof include polyvalent carboxylic acids such as butanetetracarboxylic acid, benzophenonetetracarboxylic acid and anhydrides thereof.

  Among the polyester resins, the alkylene oxide adduct of bisphenol A, which is excellent in charging characteristics and environmental stability and balanced in other electrophotographic characteristics, is preferably used. In the case of this compound, the average number of added moles of alkylene oxide is preferably 2 or more and 10 or less in terms of fixability and toner durability.

  It is preferable that 45 mol% or more and 55 mol% or less of the above-mentioned polyester resin is an alcohol component, and 55 mol% or more and 45 mol% or less is an acid component.

  In the magnetic toner of the present invention, the acid value of the polyester resin is preferably 4.0 mgKOH / g or more and 8.0 mgKOH / g or less. If the acid value of the polyester resin is less than 4.0 mgKOH / g, the polyester on the toner surface is less likely to be unevenly distributed, and the effect of adding the polyester is difficult to obtain.

  On the other hand, when the acid value of the polyester resin is greater than 8.0 mgKOH / g, the environmental difference in the toner charge amount tends to be large, and ghost is likely to occur, which is not preferable. Furthermore, if the acid value of the polyester resin is high, the electric conductivity of the Metamail extract after the toner is dispersed in methanol tends to increase, such being undesirable.

  In the present invention, two or more polyester resins may be used in combination as long as the physical properties of the obtained toner particles are not adversely affected, or the physical properties may be adjusted by modification with, for example, silicone or a fluoroalkyl group-containing compound. .

  In the magnetic toner of the present invention, the number average molecular weight of the polyester resin measured by gel permeation chromatography (GPC) is 2500 or more and 5000 or less, and the ratio of the number average molecular weight of less than 1000 is 15% or less. Is preferred. If the number average molecular weight is less than 2500, the durability tends to deteriorate. On the other hand, if the number average molecular weight exceeds 5000, the developability and durability are improved, but the low temperature fixability is hindered. Further, in the molecular weight distribution, when the ratio of the number average molecular weight less than 1000 is more than 15%, a large amount of these low molecular weight polyesters are unevenly distributed on the toner surface, and the charging characteristics of the toner are deteriorated. Further, the toner, which is an essential matter of the present invention, tends to increase the electrical conductivity when extracted with methanol.

In the magnetic toner of the present invention, the polyester resin is preferably polymerized in the presence of at least one titanium-containing catalyst represented by the following general formula (I) or (II).
Ti (-X) m (-OH) n (I)
O = Ti (-X) p (-OR) q (II)
[Wherein X is a residue obtained by removing H of one OH group from mono- or polyalkanolamine having 2 to 12 carbon atoms, and other OH groups of polyalkanolamine are directly bonded to the same Ti atom. The OH group may be polycondensed in the molecule to form a ring structure, or the OH group directly bonded to another Ti atom may be polycondensed between the molecules to form a repeating structure. The degree of polymerization in the case of forming a repeating structure is 2 or more and 5 or less. R is H or an alkyl group having 1 to 8 carbon atoms which may contain 1 to 3 ether bonds. m is an integer from 1 to 4, n is an integer from 0 to 3, and the sum of m and n is 4. p is an integer from 1 to 2, q is an integer from 0 to 1, and the sum of p and q is 2. When m or p is 2 or more, each X may be the same or different. ]

  The polyester formed in the presence of at least one titanium-containing catalyst represented by the general formula (I) or (II) has a sharp molecular weight distribution, and a component having a number average molecular weight of less than 1000 is It tends to be less than 15% and is very preferable. Further, such a polyester is preferable because it can more uniformly cover the toner surface, and ghost and electrostatic offset are improved.

  The magnetic toner of the present invention preferably contains a charge control agent for improving charging characteristics. As the charge control agent, a known one can be used, and a charge control agent that has a high charging speed and can stably maintain a constant charge amount is particularly preferable. Further, when the toner is produced using a direct polymerization method, a charge control agent having a low polymerization inhibitory property and substantially free from a solubilized product in an aqueous dispersion medium is particularly preferable. Specific compounds include, as negative charge control agents, metal compounds of aromatic carboxylic acids such as salicylic acid, alkylsalicylic acid, dialkylsalicylic acid, naphthoic acid, dicarboxylic acid, metal salts or metal complexes of azo dyes or azo pigments, sulfones Examples thereof include a polymer having an acid group, a sulfonate group, a sulfonate group, or a carboxylic acid group in the side chain, a boron compound, a urea compound, a silicon compound, and a calixarene. Examples of the positive charge control agent include a quaternary ammonium salt, a polymer having the quaternary ammonium salt in the side chain, a guanidine compound, a nigrosine compound, and an imidazole compound.

  Among these, use of a polymer having any one of a sulfonic acid group, a sulfonic acid group, and a sulfonic acid ester group (hereinafter, abbreviated as a sulfonic acid polymer) makes it easy to obtain uniform chargeability and improves ghosting. Therefore, it is preferable. In particular, when these polymers are used in a suspension polymerization method capable of suitably producing the magnetic toner of the present invention, the sulfonic acid polymer is localized on the toner surface due to its hydrophilicity and polarity. For this reason, the toner has a quick rise in charge and can have a sufficient charge amount.

  The monomer having sulfur element used in the sulfonic acid polymer used in the present invention is styrene sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, 2-methacrylamide-2-methylpropane sulfonic acid, vinyl sulfone. Acid, methacrylsulfonic acid, and the like. The sulfonic acid polymer of the present invention may be a homopolymer of the above monomer or a copolymer of the above monomer and another monomer.

  However, among them, a sulfonic acid group-containing (meth) acrylamide monomer and styrene and / or styrene- (meth) acrylic acid copolymer are preferable because the chargeability of the toner becomes very good. In this case, the mass of the sulfonic acid group-containing (meth) acrylamide monomer in 100 parts by mass of the copolymer is preferably 1.0 or more and 10.0 parts by mass or less.

  As a monomer that forms a copolymer with a monomer having a sulfur element, there is a vinyl-based polymerizable monomer, and a monofunctional polymerizable monomer or a polyfunctional polymerizable monomer should be used. I can do it.

  Monofunctional polymerizable monomers include styrene; α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, 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 -Styrene derivatives such as phenylstyrene; methyl acrylate, ethyl acrylate, n-propyl acrylate, iso-propyl acrylate, n-butyl acrylate, iso-butyl acrylate, tert-butyl acrylate, n-amyl acrylate, n-hexyl acrylate, 2 -Ethylhexyl acrylate , N-octyl acrylate, n-nonyl acrylate, cyclohexyl acrylate, benzyl acrylate, dimethyl phosphate ethyl acrylate, diethyl phosphate ethyl acrylate, dibutyl phosphate ethyl acrylate, 2-benzoyloxyethyl acrylate Methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, iso-propyl methacrylate, n-butyl methacrylate, iso-butyl methacrylate, tert-butyl methacrylate, n-amyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl Methacrylate, n-nonyl methacrylate, diethyl phosphate ethyl methacrylate Methacrylic polymerizable monomers such as dibutyl phosphate ethyl methacrylate; methylene aliphatic monocarboxylic acid esters; vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl benzoate, vinyl formate; vinyl methyl ether Vinyl ether such as vinyl ethyl ether and vinyl isobutyl ether; vinyl ketone such as vinyl methyl ketone, vinyl hexyl ketone and vinyl isopropyl ketone.

  As polyfunctional polymerizable monomers, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, tripropylene glycol Diacrylate, polypropylene glycol diacrylate, 2,2′-bis (4- (acryloxydiethoxy) phenyl) propane, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol Dimethacrylate, tetraethylene glycol dimethacrylate, polyethylene glycol Dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, polypropylene glycol dimethacrylate, 2,2'-bis (4- (methacryloxy-diethoxy) phenyl) propane, 2,2′-bis (4-methacryloxy / polyethoxy) phenyl) propane, trimethylolpropane trimethacrylate, tetramethylolmethane tetramethacrylate, divinylbenzene, divinylnaphthalene, divinyl ether, and the like.

  The method for producing the sulfur-containing polymer includes bulk polymerization, solution polymerization, emulsion polymerization, suspension polymerization, ionic polymerization and the like, but solution polymerization is preferable from the viewpoint of operability.

The polymer having a sulfonic acid group is
X (SO ₃ ⁻ ) n · mY ^{k +}
(X represents a polymer site derived from the polymerizable monomer, Y + represents a counter ion, k is a valence of the counter ion, m and n are integers, and n = k × m. .)
It has the following structure. The counter ions are preferably hydrogen ions, sodium ions, potassium ions, calcium ions, ammonium ions, and more preferably hydrogen ions.

  As a method of incorporating the charge control agent into the toner as described above, a method of adding the charge control agent to the inside of the toner particles, or a suspension polymerization, a polymerizable monomer composition charge control agent is added before granulation. The method is common. During the polymerization by forming oil droplets in water, or after polymerization, seed polymerization is performed by adding a polymerizable monomer in which a charge control agent is dissolved and suspended to cover the toner surface uniformly. It is also possible. In the case where an organometallic compound is used as the charge control agent, it is also possible to introduce the compound by adding these compounds to the toner particles, and applying a shear and mixing and stirring.

  The amount of these charge control agents used is determined by the toner production method including the type of the binder resin, the presence or absence of other additives, and the dispersion method, and is not uniquely limited. When added internally, it is preferably used in the range of 0.1 to 10 parts by mass, more preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the binder resin. In addition, when externally added, the amount is preferably 0.005 parts by mass or more and 1.0 parts by mass or less, more preferably 0.01 parts by mass or more and 0.3 parts by mass or less with respect to 100 parts by mass of the toner.

  The magnetic toner of the present invention preferably has a release agent in order to improve fixability, and the amount thereof preferably contains 1 to 30% by mass with respect to the binder resin. More preferably, it is 3 mass% or more and 25 mass% or less. When the content of the release agent is less than 1% by mass, the effect of adding the release agent is not sufficient, and further, the offset suppressing effect is also insufficient. On the other hand, if it exceeds 30% by mass, the long-term storage stability is deteriorated and the dispersibility of the toner material such as the release agent and the magnetic powder is deteriorated, and the fluidity of the magnetic toner is deteriorated and the image characteristics are deteriorated. Leads to. In addition, the release agent component oozes out and the durability under high temperature and high humidity is poor. Further, since a large amount of wax is included, the toner shape tends to become distorted.

  In general, a toner image transferred onto a recording medium is then fixed on a transfer material by energy such as heat and pressure, and a semi-permanent image is obtained. At this time, heat roll type fixing is generally used. As described above, a very high-definition image can be obtained by using a toner having a weight average particle diameter of 10 μm or less. However, when a recording medium such as paper is used, the toner particles having a small particle diameter , The heat receiving from the heat fixing roller becomes insufficient, and low temperature offset is likely to occur. However, it is possible to achieve both high image quality and fixability by incorporating an appropriate amount of a release agent in the toner according to the present invention.

  Examples of the release agent usable in the magnetic toner according to the present invention include petroleum waxes such as paraffin wax, microcrystalline wax, petrolactam and derivatives thereof, montan wax and derivatives thereof, hydrocarbon waxes and derivatives thereof by Fischer-Tropsch method. Polyolefin waxes and their derivatives typified by polyethylene, natural waxes and their derivatives such as carnauba wax and candelilla wax, and the derivatives include oxides, block copolymers with vinyl monomers, and graft modified products. Furthermore, fatty acids such as higher aliphatic alcohols, stearic acid and palmitic acid, or compounds thereof, acid amide waxes, ester waxes, ketones, hydrogenated castor oil and derivatives thereof, plant waxes, animal waxes and the like can also be used.

  The measurement of the peak top temperature of the endothermic peak of such a release agent is performed according to “ASTM D 3417-99”.

  The toner of the present invention can be produced by any known method. First, when producing by a pulverization method, for example, a binder resin, a colorant, a crystalline polyester, a release agent, a charge control agent and other necessary components and other additives are added to a Henschel mixer, a ball mill, etc. Mix thoroughly with a mixer, then melt and knead using a heat kneader such as a heated roll, kneader, or extruder to disperse or dissolve the toner material, cool and solidify, grind, classify, and surface treatment as necessary To obtain toner particles. Either the classification or the surface treatment may be performed first. In the classification step, it is preferable to use a multi-division classifier in terms of production efficiency.

  The pulverization step can be performed by a method using a known pulverizer such as a mechanical impact type or a jet type. Further, in order to obtain a toner having a preferable circularity (0.950 or more) of the present invention, it is preferable to further pulverize by applying heat or to add a mechanical impact in an auxiliary manner. Further, a hot water bath method in which finely pulverized (classified as 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 type pulverizer such as a kryptron system manufactured by Kawasaki Heavy Industries, Ltd. and a turbo mill manufactured by Turbo Industry Co. There is a method of applying a mechanical impact force to the toner by a force such as a compressive force or a frictional force by pressing the toner against the inside of the casing by a centrifugal force with a blade rotating at high speed, as in a device such as a hybridization system manufactured by the manufacturer.

  The toner of the present invention can also be produced by the pulverization method as described above, but the toner particles obtained by this pulverization method are generally irregular in shape, and have an average circularity suitably used in the present invention. In order to obtain a physical property of 0.950 or more, it is necessary to perform mechanical / thermal or some special treatment, resulting in poor productivity. Therefore, the toner of the present invention is preferably produced in an aqueous medium such as a dispersion polymerization method, an association aggregation method, a dissolution suspension method, or a suspension polymerization method. In particular, the suspension polymerization method is a suitable physical property of the present invention. It is easy to satisfy and is very preferable.

  In the suspension polymerization method, a polymerizable monomer and a colorant (in addition, a polymerization initiator, a crosslinking agent, a charge control agent, and other additives as necessary) are uniformly dissolved or dispersed to form a polymerizable monomer. After preparing the composition, the polymerizable monomer composition is dispersed in a continuous layer containing a dispersion stabilizer (for example, an aqueous phase) using an appropriate stirrer, and simultaneously subjected to a polymerization reaction to obtain a desired particle size. A toner having the above is obtained. Since the toner obtained by this suspension polymerization method (hereinafter also referred to as “polymerized toner”) has individual toner particle shapes that are substantially spherical, the physical property requirement suitable for the present invention that the average circularity is 0.950 or more. It is easy to obtain a toner that satisfies the requirements. Furthermore, since the toner has a relatively uniform charge amount distribution, an improvement in image quality can be expected.

  A method for producing toner by suspension polymerization will be described below. Suspension polymerization toner is generally a component necessary as a toner such as a colorant, a crystalline polyester, a release agent, a charge control agent, and a crosslinking agent in a polymerizable monomer constituting a toner composition, that is, a binder resin. And other additives such as a polymer, a dispersant and the like, and an aqueous medium containing a dispersion stabilizer containing a polymerizable monomer composition that is uniformly dissolved or dispersed by a disperser or the like It can be produced by suspending in it and polymerizing it.

  In the production of the polymerized toner according to the present invention, examples of the polymerizable monomer constituting the polymerizable monomer composition include the following.

  Examples of the polymerizable monomer include styrene monomers such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, and p-ethylstyrene; methyl acrylate, ethyl acrylate, Acrylate esters such as n-butyl acrylate, isobutyl acrylate, n-propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, and phenyl acrylate , Methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, Methacrylic acid dimethyl aminoethyl, methacrylic acid esters such as diethylaminoethyl methacrylate; and other acrylonitrile, methacrylonitrile, and the like monomers acrylamide. These monomers can be used alone or in combination. Among the above-mentioned monomers, styrene or a styrene derivative is preferably used alone or mixed with other monomers from the viewpoint of developing characteristics and durability of the toner.

  As the polymerization initiator used in the production of the toner according to the present invention by polymerization, it is preferable to use one having a half-life of 0.5 to 30 hours during the polymerization reaction. In addition, when the polymerization initiator is added in an amount of 0.5 to 20 parts by mass with respect to the polymerizable monomer, a polymer having a maximum between 5,000 and 50,000 can be obtained. And can provide the toner with the desired strength and suitable melting characteristics.

  Specific examples of the polymerization initiator include 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1- Carbonitrile), 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile, azo or isoazo polymerization initiators such as azobisisobutyronitrile, benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxide Peroxide polymerization initiators such as oxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, t-butylperoxy 2-ethylhexanoate, t-butylperoxypivalate, etc. Can be mentioned.

  When the toner of the present invention is produced by a polymerization method, a crosslinking agent may be added, and a preferable addition amount is 0.001 to 15 parts by mass with respect to 100 parts by mass of the polymerizable monomer.

  Here, as the crosslinking agent, a compound having two or more polymerizable double bonds is mainly used, for example, an aromatic divinyl compound such as divinylbenzene, divinylnaphthalene, etc .; for example, ethylene glycol diacrylate, ethylene glycol diester Carboxylic acid ester having two double bonds such as methacrylate, 1,3-butanediol dimethacrylate, etc .; Divinyl compounds such as divinylaniline, divinyl ether, divinyl sulfide, divinyl sulfone, etc .; and having three or more vinyl groups Are used alone or as a mixture of two or more.

  In the method for producing the toner of the present invention by a polymerization method, generally, the above-described toner composition or the like is appropriately added, and uniformly dissolved or dispersed by a dispersing machine such as a homogenizer, a ball mill, a colloid mill, or an ultrasonic dispersing machine. The polymerizable monomer composition is suspended in an aqueous medium containing a dispersion stabilizer. At this time, the particle size of the obtained toner particles becomes sharper by using a high-speed disperser such as a high-speed stirrer or an ultrasonic disperser to obtain a desired toner particle size at a stretch. The polymerization initiator may be added at the same time when other additives are added to the polymerizable monomer, or may be mixed immediately before being suspended in the aqueous medium. Also, a polymerization initiator dissolved in a polymerizable monomer or solvent can be added immediately after granulation and before starting the polymerization reaction.

  After granulation, stirring may be performed using a normal stirrer to such an extent that the particle state is maintained and particle floating and sedimentation are prevented.

  When the toner of the present invention is produced, known surfactants, organic dispersants and inorganic dispersants can be used as the dispersion stabilizer. In particular, inorganic dispersants are less likely to produce harmful ultrafine powders, and because of their steric hindrance, dispersion stability is obtained, so even if the reaction temperature is changed, stability is not easily lost, and washing is easy and does not adversely affect the toner. Therefore, it can be preferably used. Examples of such inorganic dispersants include tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, phosphate polyvalent metal salts such as hydroxyapatite, carbonates such as calcium carbonate and magnesium carbonate, calcium metasuccinate, calcium sulfate, Examples thereof include inorganic salts such as barium sulfate and inorganic compounds such as calcium hydroxide, magnesium hydroxide, and aluminum hydroxide.

  As for these inorganic dispersing agents, it is desirable to use 0.2-20 mass parts with respect to 100 mass parts of polymerizable monomers. Moreover, the said dispersion stabilizer may be used independently and may use multiple types together. Furthermore, you may use 0.001 or more and 0.1 mass part or less of surfactant together.

  When these inorganic dispersants are used, they may be used as they are, but in order to obtain finer particles, the inorganic dispersant particles can be generated and used in an aqueous medium. For example, in the case of tricalcium phosphate, a sodium phosphate aqueous solution and a calcium chloride aqueous solution can be mixed under high-speed stirring to produce water-insoluble calcium phosphate, which enables more uniform and fine dispersion. At the same time, water-soluble sodium chloride salt is produced as a by-product. However, if water-soluble salt is present in the aqueous medium, dissolution of the polymerizable monomer in water is suppressed, and ultrafine toner is generated by emulsion polymerization. This is more convenient.

  Examples of the surfactant include sodium dodecylbenzene sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, sodium stearate, potassium stearate and the like.

  In the present invention, it is preferable that at least one element selected from the group consisting of magnesium, calcium, barium, and aluminum is present on the toner surface in an amount of 5 to 1000 ppm, more preferably 10 to 500 ppm. By making the total abundance of these elements on the toner surface 5 or more and 1000 ppm or less on the basis of the toner particle mass, the charge amount of the toner can be increased and dispersed in methanol, and the electric conductivity of the supernatant liquid after dispersion is increased. The image density is high due to a synergistic effect with 2.0 to 15.0 μS / cm, and a clear image with no ghost can be obtained.

  Therefore, in the present invention, it is preferable that at least one element selected from magnesium, calcium, barium, and aluminum is present on the toner surface in an amount of 5 to 1000 ppm.

  If the amount of these elements is more than 1000 ppm, the charge amount of the toner is insufficient, resulting in an increase in fog. On the other hand, if these elements are less than 5 ppm, it tends to charge up and fog is likely to increase, such being undesirable.

  When a plurality of elements among magnesium, calcium, barium, and aluminum existing on the toner surface are present, the total amount thereof needs to be 5 or more and 1000 ppm or less.

  Such an element is preferably present on the toner surface, and the amount thereof can be arbitrarily adjusted by a method of externally adding a compound containing the element or a method for washing the dispersant as described above and conditions. Is possible.

  In the present invention, magnesium, calcium, barium, and aluminum present on the toner surface are placed in a solvent that does not dissolve the toner, such as isopropanol, and treated with an ultrasonic cleaner for 10 minutes to remove external additives. It means an element that exists in the state.

  As for the abundance of these elements, after removing external additives, the above elements are quantified using a known analysis method such as fluorescent X-ray analysis or plasma emission analysis (ICP) on the toner particles. I can do it.

  In the examples described later, the measurement of each element is performed using fluorescent X-ray analysis, and the details are in accordance with JIS-KO119.

(1) Equipment used X-ray fluorescence analyzer 3080 (Rigaku Corporation)
Sample press molding machine MAEKAWA Testing Machine (manufactured by MFG Co, LTD)

(2) Preparation of calibration curve A sample is prepared by externally adding five levels of a complex compound for quantitative determination using a coffee mill. The sample is press molded using a sample press molding machine. [M] Kα peak angle (a) in the composite compound is determined from the 2θ table. Place the calibration curve sample in the X-ray fluorescence analyzer and depressurize and vacuum the data chamber. The X-ray intensity of each sample is obtained under the following conditions, and a calibration curve (weight ratio: expressed in ppm) is created.

(3) Measurement conditions Measurement potential, voltage 50 kV, 50 to 70 mA
2θ angle a
Crystal plate LiF
Measurement time 60 seconds

(4) Quantification of the above-mentioned elements in the toner particles After forming a sample by the same method as the calibration curve, the X-ray intensity is obtained under the same measurement conditions, and the content is calculated from the calibration curve.

  When there is no compound having each element of magnesium, calcium, barium, and aluminum other than the toner surface, the amount of each element is obtained by the above method, but when any of these elements is present other than the toner surface Then, the abundance of the toner surface is obtained as follows.

  First, the abundance of each element is determined by the above method: this is abundance A. Next, the toner particles excluding the external additives are stirred in concentrated nitric acid for 1 hour, thoroughly washed with pure water, dried, and the abundance of each element is determined by the above method: The amount is B.

  The abundance of each element on the toner surface can be determined by the difference between A and B, that is, (A−B).

  Even when the above elements are contained in magnetite or the like, magnetite forms a non-moving substance with concentrated nitric acid and does not elute, so the abundance only on the surface of the toner particles can be measured.

  In the step of polymerizing the polymerizable monomer, the polymerization temperature is set to 40 ° C or higher, and generally 50 ° C to 90 ° C. When the polymerization is carried out in this temperature range, the release agent to be sealed inside precipitates by phase separation, and the encapsulation becomes more complete.

  After the polymerization of the polymerizable monomer is completed, the obtained polymer particles are filtered, washed and dried by a known method to obtain toner particles.

  In addition, the magnetic toner of the present invention can be obtained by mixing the toner particles obtained as described above with inorganic fine powder as will be described later, if necessary, and adhering them to the surface of the toner particles. It is also possible to insert a classification step in the manufacturing process (before mixing the inorganic fine powder) to cut coarse powder and fine powder contained in the toner particles.

  In the present invention, it is also a preferred form that the toner has an inorganic fine powder having a number average particle diameter of 4 to 80 nm, more preferably 6 to 40 nm as a fluidizing agent. The inorganic fine powder is added to improve the fluidity of the toner and to make the charge of the toner particles uniform. However, adjustment of the charge amount of the toner, improvement of environmental stability, etc. by treatment such as hydrophobizing the inorganic fine powder. It is also a preferable form to provide the function.

  When the number average particle size of the inorganic fine powder is larger than 80 nm, or when the inorganic fine powder of 80 nm or less is not added, good toner fluidity cannot be obtained. In addition, charging to toner particles is likely to be uneven, and problems such as an increase in fog, a decrease in image density, and an increase in consumption are unavoidable. On the other hand, when the number average particle size of the inorganic fine powder is smaller than 4 nm, the agglomeration property of the inorganic fine powder is increased, and the particle size distribution having a strong agglomeration property that is difficult to be solved by the crushing treatment instead of the primary particles is wide. It tends to behave as an aggregate. Then, it is not preferable because the aggregate is developed or the image carrier or the toner carrier is damaged by the aggregate, so that an image defect is easily generated.

  In the present invention, the number average particle diameter of the inorganic fine powder is measured using a photograph of the toner magnified by a scanning electron microscope. Furthermore, it adheres to the toner surface or is free from the toner particle surface while contrasting the photograph of the toner mapped with the element contained in the inorganic fine powder by the elemental analysis means such as XMA attached to the scanning electron microscope. It can be measured by measuring 100 or more primary particles of the inorganic fine powder, and obtaining the average primary particle size based on the number, that is, the number average particle size.

Silica, titanium oxide, alumina, etc. can be used as the inorganic fine powder used in the present invention. As the fine silica powder, for example, both a so-called dry method produced by vapor phase oxidation of silicon halide or dry silica called fumed silica, and so-called wet silica produced from water glass or the like can be used. is there. Dry silica is preferred because it has few silanol groups on the surface and in the silica fine powder, and few production residues such as Na ₂ O and SO ₃ ^2- . In dry silica, it is also possible to obtain a composite fine powder of silica and other metal oxides by using other metal halogen compounds such as aluminum chloride and titanium chloride together with silicon halogen compounds in the production process, They are also included.

  The addition amount of the inorganic fine powder having a number average particle size of 4 to 80 nm is preferably 0.1 to 3.0% by mass with respect to the toner particles. The effect is not sufficient, and if it is 3.0% by mass or more, the fixing property is deteriorated. The content of the inorganic fine powder can be quantified using a calibration curve prepared from a standard sample using fluorescent X-ray analysis.

  In the present invention, it is preferable that the inorganic fine powder has been subjected to a hydrophobization treatment because the environmental stability of the toner can be improved. When the inorganic fine powder added to the toner absorbs moisture, the charge amount of the toner particles is remarkably reduced, the charge amount is likely to be non-uniform, and toner scattering is likely to occur. Treatment agents used for hydrophobizing inorganic fine powders include silicone varnishes, various modified silicone varnishes, silicone oils, various modified silicone oils, silane compounds, silane coupling agents, other organic silicon compounds, and organic titanium compounds. May be used alone or in combination of two or more.

  Among the above treatment agents, those treated with silicone oil are preferable. More preferably, the inorganic fine powder treated with the silicone oil at the same time as or after the hydrophobizing treatment with the silane compound maintains a high charge amount of toner particles even in a high humidity environment, and prevents toner scattering. Good. As a method for treating such inorganic fine powder, for example, as a first-stage reaction, a silanization reaction is performed with a silane compound and silanol groups are eliminated by chemical bonds, and then a hydrophobic reaction is performed on the surface with silicone oil as a second-stage reaction. The thin film can be formed.

The silicone oil may have a viscosity is less than 10 200,000 mm ² / s at 25 ° C., and more preferably the following 3,000 80,000mm ² / s. If it is less than 10 mm ² / s, the inorganic fine powder is not stable, and the image quality tends to deteriorate due to heat and mechanical stress. When the viscosity of the silicone oil exceeds 200,000 mm ² / s, it tends to be difficult to uniformly treat the inorganic fine powder.

  As the silicone oil used, for example, dimethyl silicone oil, methylphenyl silicone oil, α-methylstyrene modified silicone oil, chlorophenyl silicone oil, fluorine modified silicone oil and the like are particularly preferable.

  Examples of the method for treating the inorganic fine powder with silicone oil include a method of directly mixing the inorganic fine powder treated with the silane compound and the silicone oil using a mixer such as a Henschel mixer, or a method of treating the inorganic fine powder with the silicone oil. The method of spraying is mentioned. Alternatively, after dissolving or dispersing silicone oil in an appropriate solvent, an inorganic fine powder may be added and mixed to remove the solvent. A spraying method is more preferred because it produces relatively few aggregates of inorganic fine powder.

  The treatment amount of the silicone oil is 1 to 40 parts by mass, preferably 3 to 35 parts by mass with respect to 100 parts by mass of the inorganic fine powder. If the amount of silicone oil is too small, good hydrophobicity cannot be obtained, and if it is too large, problems such as fogging tend to occur.

The inorganic fine powder used in the present invention preferably has a specific surface area of 20 or more and 350 m ² / g or less, measured by the BET method by nitrogen adsorption, in order to impart good fluidity to the toner, and 25 or more and 300 m ^2. / G or less is more preferable. The specific surface area is calculated using the BET multipoint method by adsorbing nitrogen gas to the sample surface using a specific surface area measuring device Autosorb 1 (manufactured by Yuasa Ionics) according to the BET method.

The toner of the present invention has a primary particle size of more than 30 nm (preferably a specific surface area of less than 50 m ² / g), more preferably a primary particle size of 50 nm or more (preferably a specific surface area of 30 m) for the purpose of improving cleaning properties. It is also one of preferable modes to add inorganic or organic fine particles close to spherical shape (less than ² / g) to the toner particles. For example, spherical silica particles, spherical polymethylsilsesquioxane particles, spherical resin particles and the like are preferably used.

  In the toner of the present invention, other additives such as a lubricant powder such as a polyfluorinated ethylene powder, a zinc stearate powder, and a polyvinylidene fluoride powder; a cerium oxide powder, a silicon carbide powder within a range that does not substantially adversely affect the toner. An abrasive such as strontium titanate powder; a fluidity-imparting agent such as titanium oxide powder or aluminum oxide powder; an anti-caking agent; or organic fine particles and inorganic fine particles of opposite polarity can be used in small amounts as a developability improver. It is also possible to use the surface of these additives after hydrophobizing them.

  Next, a method for measuring each physical property related to the toner of the present invention will be described.

(1) Electric conductivity of magnetic toner Disperse and stir at room temperature (23.0 ° C.) for 30 minutes by dispersing 5.0 g of magnetic toner in 100 g of methanol (manufactured by Kishida Chemical Co., Ltd., special grade). Thereafter, the toner is precipitated by a magnet to obtain a supernatant. The obtained supernatant was measured with a conductivity meter (manufactured by Horiba, Ltd., ES-12).

(2) Desorption rate of magnetic powder treatment agent 1 g of magnetic powder fired at 500 ° C. was dissolved by heating in 10 ml of concentrated hydrochloric acid, and then pure water was added to make the total volume 100 ml (mother liquor). 20 ml was taken from the mother liquor, and pure water was added to make a total solution of 100 ml (for measurement). Further, 20 ml was taken from the mother liquor, a predetermined amount of a silica standard solution for atomic absorption analysis was added, and then a pure water was added to make a total amount of 100 ml (for standardization).

  Next, using an ICP emission spectrometer (Vista-PRO (trade name) manufactured by Seiko Instruments Inc.), the Si amount (mg) in the measurement solution is obtained by the standard addition method, and the Si amount (%) of the magnetic powder is calculated. did.

  Here, the Si amount of the magnetic powder subjected to the hydrophobization treatment is Si-1, and the Si amount of the magnetic powder not subjected to the hydrophobization treatment is Si-2.

  On the other hand, 20.0 g of hydrophobized magnetic powder and 13.0 g of toluene were placed in a 50 ml screw tube bottle, shaken, and then irradiated with ultrasonic waves for 60 minutes with an ultrasonic disperser. Then, after centrifuging at 2000 rpm for 15 minutes using a centrifuge, the supernatant was removed to obtain a precipitate. The obtained precipitate was dried at 90 ° C. for 1 hour, and then the Si amount (Si-3) of the magnetic powder was measured by the above method.

Here, the value obtained by subtracting Si-2 from Si-1 is the amount of the processing agent contained in the magnetic powder, and the value obtained by subtracting Si-2 from Si-3 is dispersed in toluene for 60 minutes. It becomes the amount of the processing agent contained in the magnetic powder. Using these, the desorption rate of the treatment agent is obtained by the following equation.
Desorption rate = {1- (Amount of treatment agent contained in magnetic powder after being dispersed in toluene for 60 minutes) / (Amount of treatment agent contained in magnetic powder)} × 100

(3) Average particle size and particle size distribution of toner The weight average particle size and particle size distribution of the toner of the present invention can be measured by various methods using a Coulter Counter TA-II type or Coulter Multisizer (manufactured by Coulter). It is. In the present invention, a Coulter Multisizer (manufactured by Coulter Inc.) is used, and an interface (manufactured by Nikkiki) and a PC9801 personal computer (manufactured by NEC) for outputting the number distribution and volume distribution are connected thereto. As the electrolytic solution, a 1% NaCl aqueous solution prepared using primary sodium chloride is used. As such an electrolytic solution, for example, ISOTON R-II (manufactured by Coulter Scientific Japan) can be used.

  The measurement procedure is as follows. 5 ml of a surfactant (alkylbenzene sulfonate) is added as a dispersant to 100 ml of the electrolytic solution, and 10 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment for 1 minute by an ultrasonic disperser, and the number distribution is calculated by measuring the number of toner particles having a size of 2 μm or more using the 100 μm aperture as an aperture by the Coulter multisizer. Based on this, the weight average particle diameter is determined.

(4) Average circularity and mode circularity of the toner The average circularity and the mode circularity of the toner are measured using a flow type particle image measuring device “FPIA-2100 type” (manufactured by Sysmex Corporation). Use to calculate.

  Here, the “particle projected area” is the area of the binarized toner particle image, and the “peripheral length of the particle projected image” is the length of the contour line obtained by connecting the edge points of the toner particle image. Define. The measurement uses the perimeter of the particle image when image processing is performed at an image processing resolution of 512 × 512 (pixels of 0.3 μm × 0.3 μm).

  In the present invention, the circularity is an index indicating the degree of unevenness of the toner particles, and is 1.000 when the toner particles are completely spherical. The more complicated the surface shape, the smaller the circularity. The average circularity C, which means the average value of the circularity frequency distribution, is calculated from the following equation, where ci is the circularity (center value) at the dividing point i of the particle size distribution and m is the number of measured particles.

  The mode circularity is a circularity value having the highest frequency in the circularity frequency distribution.

  In addition, “FPIA-2100”, which is a measuring apparatus used in the present invention, calculates the circularity of each particle and then calculates the average circularity and the circularity standard deviation. 0.4 to 1.0 are divided into equally divided classes every 0.01, and the average circularity and circularity standard deviation are calculated using the center value of the dividing points and the number of measured particles.

  The measurement procedure is as follows. A dispersion is prepared by dispersing 5 mg of toner in 10 ml of water in which 0.1 mg of a surfactant is dissolved, and the dispersion is irradiated with ultrasonic waves (20 kHz, 50 W) for 5 minutes. The concentration of the dispersion is 5000 or more and 20,000. The number of particles / μl or less is measured by the above apparatus, and the average circularity of a particle group having an equivalent circle diameter of 3 μm or more is obtained.

  In this measurement, the reason for measuring the circularity only for the particle group having an equivalent circle diameter of 3 μm or more is as follows. The group of particles having an equivalent circle diameter of less than 3 μm includes a group of external additives that exist independently from the toner particles. The influence of these external additives is eliminated, and the toner particles are more accurately circular. This is to obtain the degree. In order to suppress variation in circularity, the installation environment of the apparatus is controlled at 23 ° C. ± 0.5 ° C. so that the temperature inside the flow type particle image analyzer FPIA-2100 is 26 to 27 ° C. Preferably, autofocus is performed using 2 μm latex particles every 2 hours.

  Furthermore, “FPIA-2100”, which is a measuring apparatus used in the present invention, improves the magnification of the processed particle image as compared with “FPIA-1000” conventionally used for calculating the shape of the toner. Furthermore, the accuracy of toner shape measurement has been improved by improving the processing resolution of the captured image (256 × 256 → 512 × 512), thereby achieving more reliable capture of fine particles. Therefore, when it is necessary to measure the shape more accurately as in the present invention, the FPIA-2100 that can obtain information on the shape more accurately is more useful.

(5) Molecular weight measurement of polyester resin The molecular weight of the polyester resin is measured as follows. A solution in which a polyester resin is allowed to stand in THF for 24 hours at room temperature and dissolved is filtered through a solvent-resistant membrane filter having a pore diameter of 0.2 μm to obtain a sample solution, which is measured under the following conditions. In preparing the sample solution, the amount of THF is adjusted so that the concentration of the component soluble in THF is 0.4 or more and 0.6% by mass or less.
Equipment: High-speed GPC HLC8120 GPC (manufactured by Tosoh Corporation)
Column: Seven series of Shodex KF-801, 802, 803, 804, 805, 806, 807 (manufactured by Showa Denko KK)
Eluent: THF
Flow rate: 1.0 ml / min
Oven temperature: 40.0 ° C
Sample injection volume: 0.10 ml

  In calculating the molecular weight of the sample, standard polystyrene resin (TSO standard polystyrene F-850, F-450, F-288, F-128, F-80, F-40, F-20, F- manufactured by Tosoh Corporation) was used. 10, F-4, F-2, F-1, A-5000, A-2500, A-1000, A-500).

(7) Method for Measuring Acid Value of Polyester Resin The acid value of the polyester resin is measured according to JIS K1557-1970. A specific measurement method is shown below. 2.0 g of the pulverized sample is precisely weighed (W (g)). A sample is put into a 200 ml Erlenmeyer flask, 100 ml of a mixed solution of toluene / ethanol (2: 1) is added and dissolved for 5 hours. Add phenolphthalein solution as indicator. 0.1N KOH is also titrated with a burette using an alcohol solution. The amount of the KOH solution at this time is S (ml). A blank test is performed, and the amount of the KOH solution at this time is defined as B (ml).

The acid value is calculated by the following formula.
Acid value = [(SB) × f × 5.61] / W
(F: Factor of KOH solution)

(8) Confirmation of Core-Shell Structure In the present invention, confirmation of the core-shell structure of the toner is performed as follows. Specifically, after the toner is sufficiently dispersed in the ultraviolet curable acrylic resin, the acrylic resin is irradiated with ultraviolet rays and cured. After the surface of the cured product obtained using an ultramicrotome is subjected to electron staining using ruthenium tetroxide (RuO ₄ ) or, if necessary, osmium tetroxide (OsO ₄ ), diamond A flaky sample is cut out using an ultramicrotome equipped with a knife. By observing the obtained sample using a transmission electron microscope (TEM), the cross-sectional layer form of the toner is observed, and a micrograph is obtained. The core-shell structure is confirmed from the sectional photograph of the toner thus obtained (for example, a sectional photograph magnified 40,000 times).

  Next, an example of an image forming apparatus that 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, which is provided with 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. The photosensitive drum 100 is charged to, for example, −600 V by the primary charging roller 117 (applied voltages are, for example, an AC voltage of 1.85 kVpp and a DC voltage of −620 Vdc). Then, exposure is performed by irradiating the photoreceptor 100 with the laser beam 123 by the laser generator 121, and an electrostatic latent image corresponding to the target image is formed. The electrostatic latent image on the photosensitive drum 100 is developed with a one-component magnetic 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 that is in contact with the photoreceptor via the transfer material. Transcribed. The transfer material on which the toner image is placed is conveyed to the fixing device 126 by the conveying belt 125 or the like and fixed on the transfer material. In addition, toner remaining on a part of the photoconductor is cleaned by a cleaner 116.

  Although an image forming apparatus for magnetic one-component jumping development is shown here, the toner of the present invention may be a magnetic toner or a non-magnetic toner, and either a one-component development method or a two-component development development method is used. The toner used in the toner may be used. Furthermore, it may be used for any method of jumping development or contact development.

  Hereinafter, the present invention will be described more specifically with reference to production examples and examples, but these do not limit the present invention in any way.

<Examples of magnetic powder production>
In ferrous sulfate aqueous solution, l. 0 to 1.1 equivalent of caustic soda solution, P ₂ O _{5 in} an amount of 0.15% by mass in terms of phosphorus with respect to iron element, and 0.50% by mass in terms of silicon with respect to iron element Of SiO ₂ were mixed to prepare an aqueous solution containing ferrous hydroxide. The pH of the aqueous solution was 8.0, and an oxidation reaction was performed at 85 ° C. while blowing air to prepare a slurry liquid having seed crystals.

  Next, after adding ferrous sulfate aqueous solution to this slurry liquid so that it becomes 0.9 or more and 1.2 equivalent or less with respect to the initial alkali amount (sodium component of caustic soda), the slurry liquid is maintained at pH 7.6. Then, an oxidation reaction was promoted while blowing air to obtain a slurry liquid containing magnetic iron oxide. After filtration and washing, the water-containing slurry was once taken out. At this time, a small amount of water-containing sample was collected and the water content was measured. Next, the water-containing sample is put into another aqueous medium without being dried, stirred and redispersed with a pin mill while circulating the slurry, and the pH of the redispersed liquid is adjusted to about 4.8 and stirred. While adding 1.6 parts by mass of n-hexyltrimethoxysilane to 100 parts by mass of magnetic iron oxide (the amount of magnetic iron oxide was calculated by subtracting the water content from the water-containing sample), hydrolysis was performed. . Thereafter, the mixture was sufficiently stirred and dispersed with a pin mill while circulating the slurry, and the pH of the dispersion was set to 8.6 to perform a coupling treatment. The produced hydrophobic magnetic powder was filtered with a filter press, washed with a large amount of water, and then air-dried. Thereafter, drying was performed at 100 ° C. for 15 minutes and 90 ° C. for 30 minutes, and the obtained particles were crushed to obtain a magnetic powder having a volume average particle diameter of 0.23 μm. Table 1 shows the physical properties of the magnetic powder 1 obtained.

<Manufacture of magnetic powder 2>
In the production of magnetic powder 1, the amount of n-hexyltrimethoxysilane was changed to 1.0 part by mass with respect to 100 parts by mass of magnetic iron oxide, and the drying conditions were changed to 30 minutes at 100 ° C. and 60 minutes at 150 ° C. Except for this, the magnetic powder 1 was obtained in the same manner as in the production of the magnetic powder 1. Table 1 shows the physical properties of the magnetic powder 1 obtained.

<Manufacture of magnetic powder 3>
In the production of magnetic powder 1, the amount of n-hexyltrimethoxysilane was 2.8 parts by mass with respect to 100 parts by mass of magnetic iron oxide, and the drying conditions were changed to 60 ° C. for 4 hours. Magnetic powder 3 was obtained in the same manner as in the production. Table 1 shows the physical properties of the magnetic powder 3 obtained.

<Manufacture of magnetic powder 4>
In the production of the magnetic powder 1, the SiO ₂ to be added is changed to SiO ₂ in an amount of 0.30% by mass in terms of silicon element, and the P ₂ O ₅ is not added. Similarly, magnetic powder 4 was obtained. Table 1 shows the physical properties of the magnetic powder 4 thus obtained.

  The residual magnetization in the table is a value when magnetized with a magnetic field of 79.6 kA / m (1000 oersted), and the strength of magnetization is the strength of magnetization in the magnetic field of 79.6 kA / m (1000 oersted). That's it.

<Synthesis of titanium-containing catalyst A>
Into a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen introducing tube capable of bubbling in the liquid, 1617 parts by mass of titanium diisopropoxybis (triethanolaminate) and 126 parts by mass of ion-exchanged water are added, and the solution is liquid with nitrogen. Under moderate bubbling, the temperature was gradually raised to 90 ° C. and reacted (hydrolyzed) at 90 ° C. for 4 hours to obtain titanium dihydroxybis (triethanolaminate) [catalyst A].

Incidentally, -X in formula (I) is a _{-OCH 2 CH 2 N (CH 2} CH 2 OH) 2, is m = 2, n = 2.

<Synthesis of titanium-containing catalyst B>
In a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen introducing tube capable of bubbling in the liquid, 1617 parts by mass of titanium diisopropoxybis (triethanolaminate) and 126 parts by mass of ion-exchanged water are placed, and the solution is liquid with nitrogen. Under moderate bubbling, the temperature was gradually raised to 90 ° C. and reacted (hydrolyzed) at 90 ° C. for 4 hours to obtain titanium dihydroxybis (triethanolaminate). The obtained compound was heated in a nitrogen atmosphere to dehydrate the hydroxyl group to obtain a titanium-containing catalyst having a titanyl structure [Catalyst B].

Note that -X in formula (II) is a _{-OCH 2 CH 2 N (CH 2} CH 2 OH) 2, is p = 2, q = 0.

<Synthesis of polyester resin 1>
The following components were placed in a reaction vessel equipped with a cooling tube, a stirrer, and a nitrogen introduction tube, and reacted for 10 hours while distilling off the water produced at 230 ° C. under a nitrogen stream.
Bisphenol A EO 2 mol adduct 350 parts by mass Bisphenol A PO 2 mol adduct 326 parts by mass Terephthalic acid 278 parts by mass Titanium-containing catalyst A 2 parts by mass Then, the reaction is performed under reduced pressure of 5 to 20 mmHg, and the acid value becomes 2 or less. At that time, it was cooled to 180 ° C., 62 parts by mass of trimellitic anhydride was added, taken out after reaction for 2 hours under sealed at normal pressure, cooled to room temperature, pulverized, and polyester resin 1 was obtained. Table 2 shows the physical properties of the obtained resin.

<Synthesis of polyester resin 2>
In the production of the polyester resin 1, a polyester resin 2 was obtained in the same manner as the production of the polyester resin 1 except that the titanium-containing catalyst A was changed to the titanium-containing catalyst B. Table 2 shows the physical properties of the obtained resin.

<Synthesis of polyester resin 3>
In the production of polyester resin 1, polyester resin 3 was obtained in the same manner as in the production of polyester resin 1 except that trimellitic anhydride was not added. Table 2 shows the physical properties of the obtained resin.

<Synthesis of polyester resin 4>
In the production of polyester resin 1, polyester resin 4 was obtained in the same manner as in the production of polyester resin 1 except that 62 parts by mass of trimellitic anhydride was changed to 118 parts by mass. Table 2 shows the physical properties of the obtained resin.

<Synthesis of polyester resin 5>
In the production of the polyester resin 1, a polyester resin 5 was obtained in the same manner as in the production of the polyester resin 1 except that 2 parts by mass of the titanium-containing catalyst A was changed to 3.5 parts by mass. Table 2 shows the physical properties of the obtained resin.

<Synthesis of polyester resin 6>
In the production of the polyester resin 1, a polyester resin 6 was obtained in the same manner as in the production of the polyester resin 1 except that 2 parts by mass of the titanium-containing catalyst A was changed to 1.4 parts by mass. Table 2 shows the physical properties of the obtained resin.

<Synthesis of polyester resin 7>
In the production of the polyester resin 1, a polyester resin 7 was obtained in the same manner as in the production of the polyester resin 1 except that the titanium-containing catalyst A was changed to antimony. Table 2 shows the physical properties of the obtained resin.

<Synthesis of polyester resin 8>
In the production of the polyester resin 1, a polyester resin 7 was obtained in the same manner as in the production of the polyester resin 1 except that the titanium-containing catalyst A was changed to antimony. 100 parts by mass of the obtained polyester resin 7 was put into 2000 parts by mass of methanol, stirred at room temperature for 10 hours, filtered and dried to obtain polyester resin 8. Table 2 shows the physical properties of the obtained resin.

<Production of sulfonic acid group-containing polymer>
In a pressurizable reaction vessel equipped with a reflux tube, a stirrer, a thermometer, a nitrogen introduction tube, a dropping device and a decompression device, 250 parts by mass of methanol as a solvent, 150 parts by mass of 2-butanone and 100 parts by mass of 2-propanol, As a monomer, 83 parts by mass of styrene, 12 parts by mass of butyl acrylate, and 4 parts by mass of 2-acrylamido-2-methylpropanesulfonic acid (hereinafter abbreviated as AMPS) were added and heated to reflux temperature while stirring. A solution prepared by diluting 0.45 parts by mass of t-butylperoxy-2-ethylhexanoate as a polymerization initiator with 20 parts by mass of 2-butanone was added dropwise over 30 minutes, and stirring was continued for 5 hours. A solution prepared by diluting 0.28 parts by mass of butylperoxy-2-ethylhexanoate with 20 parts by mass of 2-butanone was added dropwise over 30 minutes, and the mixture was further stirred for 5 hours for polymerization.

  Thereafter, the reaction solution was put into methanol to precipitate a polymer. The obtained polymer was dried to obtain a sulfonic acid group-containing polymer.

<Manufacture of magnetic toner 1>
After adding 450 parts by mass of 0.1M Na ₃ PO ₄ aqueous solution to 720 parts by mass of ion-exchanged water and heating to 60 ° C., 67.7 parts by mass of 1.0 M CaCl ₂ aqueous solution was added to stabilize the dispersion. An aqueous medium containing the agent was obtained.

Styrene 76.0 parts by mass n-butyl acrylate 24.0 parts by mass divinylbenzene 0.53 parts by mass sulfonic acid group-containing polymer 1.0 part by mass polyester resin 1 5.0 parts by mass magnetic powder 1 90.0 mass parts The said prescription was uniformly disperse-mixed using the attritor (Mitsui Miike Kako Co., Ltd.), and the monomer composition was obtained. The monomer composition was heated to 60 ° C., and 15 parts by mass of paraffin wax (melting point: 78 ° C.) was added and dissolved therein, followed by polymerization initiator 2,2′-azobis (2,4-dimethylvalero). Nitrile) 4.5 parts by mass was dissolved.

The monomer composition was put into the aqueous medium, and granulated by stirring at 12,000 rpm for 10 minutes in a TK homomixer (Special Machine Industries Co., Ltd.) in an N ₂ atmosphere at 60 ° C. Thereafter, the reaction was carried out at 70 ° C. for 5 hours while stirring with a paddle stirring blade, and then the temperature was raised to 80 ° C. and the mixture was stirred for 2 hours. After completion of the reaction, the suspension was cooled, hydrochloric acid was added to adjust the pH to 0.8, and the mixture was stirred for 2 hours, followed by filtration. Further, the toner particles 1 were obtained by washing three times with 2000 parts by mass or more of ion-exchanged water, sufficiently ventilating, and drying.

100 parts by mass of this toner particle 1 and silica having a number average particle diameter of 12 nm are treated with hexamethyldisilazane and then with silicone oil, and a hydrophobic silica fine powder 1.0 having a BET value of 120 m ² / g after the treatment is obtained. Mass parts were mixed with a Henschel mixer (Mitsui Miike Chemical Co., Ltd.) to obtain a magnetic toner 1 having a weight average particle diameter of 7.2 μm. When the obtained toner was confirmed with a transmission electron microscope (TEM), it was confirmed that the polyester resin 1 formed a surface layer and had a core-shell structure in which paraffin wax was encapsulated. Table 3 shows the physical properties of the magnetic toner 1.

<Production Example of Magnetic Toner 2>
In the production example of magnetic toner 1, after completion of the polymerization reaction, hydrochloric acid was added to adjust the pH to 1.5, and the mixture was stirred for 2 hours and filtered. Thereafter, the magnetic toner 2 was obtained in the same manner as in the production of the magnetic toner 1 except that it was washed twice with 2000 parts by mass or more of ion exchange water. Table 3 shows the physical properties of the magnetic toner 2.

<Production Example of Magnetic Toner 3>
In the production example of magnetic toner 1, after completion of the polymerization reaction, hydrochloric acid was added to adjust pH = 3.0, and the mixture was stirred for 2 hours and filtered. Thereafter, a magnetic toner 3 was obtained in the same manner as in the production of the magnetic toner 1 except that it was washed twice with 500 parts by mass or more of ion exchange water. Table 3 shows the physical properties of the magnetic toner 3.

<Production Example of Magnetic Toner 4>
In the production of the magnetic toner 1, after completion of the polymerization reaction, hydrochloric acid was added to adjust the pH to 0.8, and the mixture was stirred for 2 hours and filtered. Thereafter, it was washed twice with 2000 parts by mass or more of ion-exchanged water and filtered. 100 parts by mass of the filtrate was put into 2000 parts by mass of a mixed solution of water / methanol = 1: 1, stirred and dispersed, and then filtered. Thereafter, a magnetic toner 4 was obtained in the same manner as in the production of the magnetic toner 1 except that it was washed three times with 2000 parts by mass or more of ion exchange water. Table 3 shows the physical properties of the magnetic toner 4.

<Production Example of Magnetic Toner 5>
In the production example of the magnetic toner 1, the magnetic toner 5 was prepared in the same manner as in the production of the toner 1 except that a chromium compound of a monoazo complex (S-34: manufactured by Hodogaya Chemical Co., Ltd.) was used instead of the sulfonic acid group-containing polymer. Obtained. Table 3 shows the physical properties of the magnetic toner 5.

<Production Example of Magnetic Toner 6>
In the production example of the magnetic toner 1, the magnetic toner 6 was obtained in the same manner as the production of the toner 1 except that the magnetic powder 2 was used instead of the magnetic powder 1. Table 3 shows the physical properties of the magnetic toner 6.

<Example of manufacturing magnetic toner 7>
In the production example of the magnetic toner 1, a magnetic toner 7 was obtained in the same manner as in the production of the toner 1 except that the magnetic powder 3 was used instead of the magnetic powder 1. Table 3 shows the physical properties of the magnetic toner 7.

<Production Example of Magnetic Toner 8>
In the production example of the magnetic toner 1, the magnetic toner 8 was obtained in the same manner as in the production of the toner 1 except that the magnetic powder 4 was used instead of the magnetic powder 1. Table 3 shows the physical properties of the magnetic toner 8.

<Production Example of Magnetic Toner 9>
Magnetic toner 9 was obtained in the same manner as in the above production example except that polyester resin 2 was used instead of polyester resin 1 in the production example of magnetic toner 1. Table 3 shows the physical properties of the magnetic toner 9.

<Production Example of Magnetic Toner 10>
A magnetic toner 10 was obtained in the same manner as in the above production example except that the polyester resin 3 was used instead of the polyester resin 1 in the production example of the magnetic toner 1. Table 3 shows the physical properties of the magnetic toner 10.

<Production Example of Magnetic Toner 11>
Magnetic toner 11 was obtained in the same manner as in the above production example except that polyester resin 4 was used instead of polyester resin 1 in the production example of magnetic toner 1. Table 3 shows the physical properties of the magnetic toner 11.

<Production Example of Magnetic Toner 12>
Magnetic toner 12 was obtained in the same manner as in the above production example except that polyester resin 5 was used in place of polyester resin 1 in the production example of magnetic toner 1. Table 3 shows the physical properties of the magnetic toner 12.

<Production Example of Magnetic Toner 13>
A magnetic toner 13 was obtained in the same manner as in the above production example except that the polyester resin 6 was used instead of the polyester resin 1 in the production example of the magnetic toner 1. Table 3 shows the physical properties of the magnetic toner 13.

<Example of production of magnetic toner 14>
A magnetic toner 14 was obtained in the same manner as in the above production example except that the polyester resin 7 was used in place of the polyester resin 1 in the production example of the magnetic toner 1. Table 3 shows the physical properties of the magnetic toner 14.

<Example of manufacturing magnetic toner 15>
In the production example of the magnetic toner 1, a magnetic toner 15 was obtained in the same manner as in the production example described above except that the polyester resin 8 was used instead of the polyester resin 1. Table 3 shows the physical properties of the magnetic toner 15.

<Example of Production of Magnetic Toner 16>
Magnetic toner 16 was obtained in the same manner as in the above production example except that magnetic powder 2 was used instead of magnetic powder 1 and polyester resin 8 was used instead of polyester resin 1 in the production example of magnetic toner 1. . Table 2 shows the physical properties of the magnetic toner 16.

<Example of manufacturing magnetic toner 17>
Magnetic toner 17 was obtained in the same manner as in the above production example except that magnetic powder 3 was used in place of magnetic powder 1 and polyester resin 7 was used in place of polyester resin 1 in the production example of magnetic toner 1. . Table 2 shows the physical properties of the magnetic toner 17.

<Example of Production of Magnetic Toner 18>
Magnetic toner 18 was obtained in the same manner as in the above production example, except that in the production example of magnetic toner 1, the amount of divinylbenzene was changed from 0.53 parts by mass to 0.10 parts by mass. Table 2 shows the physical properties of the magnetic toner 18.

<Example of manufacturing magnetic toner 19>
A magnetic toner 19 was obtained in the same manner as in the above production example, except that in the production example of the magnetic toner 1, the amount of divinylbenzene was changed from 0.53 parts by mass to 1.20 parts by mass. Table 2 shows the physical properties of the magnetic toner 19.

なお、トナー２から１９に関して、トナー１同様に透過型電子顕微鏡（ＴＥＭ）にて確認したところ、いずれのトナーもコア−シェル構造を有している事が確認された。
※１：水分散液の電気伝導度はイオン交換水１００ｇに磁性トナー５．０ｇを加え、３０分間煮沸。その後、マグネットによりトナーを沈殿させ、上澄み液を得る。得られた上澄み液を導電率計（堀場製作所社製、ＥＳ−１２）にて測定を行った値である。

As for toners 2 to 19, as in toner 1, it was confirmed with a transmission electron microscope (TEM) that it was confirmed that all toners had a core-shell structure.
* 1: The electrical conductivity of the aqueous dispersion is obtained by adding 5.0 g of magnetic toner to 100 g of ion-exchanged water and boiling for 30 minutes. Thereafter, the toner is precipitated by a magnet to obtain a supernatant. It is the value which measured the obtained supernatant liquid with the conductivity meter (Horiba Ltd. make, ES-12).

  As is apparent from the table, there is no correlation between the electrical conductivity of the aqueous dispersion and the electrical conductivity of the methanol dispersion.

<Example 1>
(Image forming device)
As the image forming apparatus, a modified LBP3410 (manufactured by Canon) was used. Here, a development bias in which an alternating electric field of 1.5 kVpp and a frequency of 2200 Hz is superimposed on a DC voltage Vdc of −430 V was used. Under this condition, the magnetic toner 1 is used, and the printing rate is set using 8-point A characters in a low temperature and low humidity environment (15 ° C., 10% RH) and in a high temperature and high humidity environment (32.5 ° C., 80% RH). An image endurance test of 3000 sheets was performed in a continuous mode with an image of 4%. As the recording medium, A4 75 g / m ² paper was used.

  As a result, there was no ghost and fog on the non-image area before and after the durability test, and a high density image could be obtained. Also, no electrostatic offset occurred in a low temperature environment. The evaluation results are shown in Table 3.

  The evaluation methods for each evaluation performed in the examples and comparative examples of the present invention and the judgment criteria thereof will be described below.

1) Image density The image density formed a solid image portion, and the density of the solid image was measured with a Macbeth reflection densitometer (manufactured by Macbeth).

2) Fog A white image was output, and the reflectance was measured using a REFECTMETER MODEL TC-6DS manufactured by Tokyo Denshoku. On the other hand, the reflectance of the transfer paper (standard paper) before white image formation was measured in the same manner. For the filters, black and magenta toners used green filters, cyan toners used amber filters, and yellow toners used blue filters. The fog was calculated from the reflectance before and after the white image output using the following formula.
Fog (reflectance) (%) = reflectance of standard paper (%)-reflectance of white image sample (%)

The determination criteria for fogging are as follows.
A: Very good (less than 1.5%)
B: Good (1.5% or more and less than 2.5% or less)
C: Normal (2.5% or more and less than 4.0% or less)
D: Poor (4% or more)

3) Ghost 10mm x 10mm solid images are placed in the first half of the image, the second half is a 2-dot 3-space halftone image, and it is judged visually how much trace of the solid image appears on the halftone image. To do.
A: Very good (ghost is not generated).
B: Good.
C: An image having no problem in practical use.
D: An image with a bad ghost level and unpreferable for practical use.

4) Electrostatic offset In a low-temperature and low-humidity environment, a plurality of solid images of 10 mm × 10 mm are put out in the first half of the image, the second half is a solid white image, and whether the latter half of the solid white image is dirty is visually checked below. Judged by the criteria of.
A: Good (no stain is generated).
B: An image having no problem in practical use.
C: An image in which a solid white portion is soiled and is not practically preferable.

<Examples 2 to 16>
The image endurance test and the fixing test were conducted in the same manner as in Example 1 except that magnetic toners 2 to 8 and 12 to 19 were used. As a result, each toner obtained an image of a level higher than the practical level before and after the durability test, and showed good fixability. The evaluation results are shown in Tables 3 and 4.

<Comparative Examples 1 to 5>
An image forming test and a fixing test were performed in the same manner as in Example 1 except that the magnetic toners 9 to 11, 20, and 21 were used. As a result, the density of the magnetic toners 9 and 10 decreased in a high temperature and high humidity environment, and the pressure roller was dirty. Although the magnetic toner 11 has good low-temperature fixability, toner fusion occurred during durability in a high-temperature and high-humidity environment. The magnetic toners 20 and 21 obtained good images through durability, but the low-temperature fixability was poor. The evaluation results are shown in Tables 3 and 4.

FIG. 2 is a schematic cross-sectional view illustrating an example of an image forming apparatus that can suitably use the toner of the present invention.

Explanation of symbols

100 Photosensitive drum (image carrier, charged body)
102 Developing sleeve (magnetic toner carrier)
114 Transfer charging roller (transfer member)
116 Cleaner 117 Primary charging roller (contact charging member)
121 Laser generator (latent image forming means, exposure device)
123 Laser light 124 Register roller 125 Conveying belt 126 Fixing device 140 Developing device 141 Stirring member

Claims (11)

  In a magnetic toner having at least a binder resin and magnetic powder, the magnetic toner is dispersed in methanol, and the electric conductivity of the supernatant after dispersion is 2.0 μS / cm or more and 15.0 μS / cm or less. Magnetic toner.   The magnetic toner according to claim 1, wherein the magnetic toner is dispersed in methanol, and the electric conductivity of the supernatant after dispersion is 2.0 μS / cm or more and 10.0 μS / cm or less.   The magnetic toner according to claim 1, wherein an average circularity of the magnetic toner is 0.950 or more. The residual magnetization when magnetized with a magnetic field of 79.6 kA / m (1000 oersted) is 2.0 Am ² / kg (emu / g) or less, according to any one of claims 1 to 3. Magnetic toner.   The magnetic toner has at least one element selected from the group consisting of magnesium, calcium, barium, and aluminum, and the total amount of the element on the toner surface is 5 or more and 1000 ppm or less based on the toner particle mass. The magnetic toner according to claim 1.   6. The magnetic toner according to claim 1, wherein the resin component of the magnetic toner has a tetrahydrofuran (THF) insoluble content of 5.0% by mass or more and 50.0% by mass or less. The magnetic powder is hydrophobized with a treatment agent, and the removal rate of the treatment agent obtained by the following formula (1) is 3% or more and 30% or less. The magnetic toner according to any one of the above.
Desorption rate = {1- (Amount of treatment agent contained in magnetic powder after being dispersed in toluene for 60 minutes) / (Amount of treatment agent contained in magnetic powder)} × 100 (1) )   The magnetic toner according to claim 1, wherein the magnetic toner has a core-shell structure.   9. The magnetic toner according to claim 8, wherein the shell layer is made of a polymer containing a polyester resin as a main component, and the acid value of the polyester resin is 4.0 mgKOH / g or more and 8.0 mgKOH / g or less. .   The number average molecular weight when the polyester resin is measured by gel permeation chromatography (GPC) is 2500 or more and 5000 or less, and the number average molecular weight is less than 1000 and the component is less than 15% of the whole polyester resin. The magnetic toner according to claim 9. 11. The polyester resin according to claim 9, wherein the polyester resin is a resin polymerized in the presence of at least one titanium-containing catalyst represented by the following general formula (I) or (II): Magnetic toner.
Ti (-X) m (-OH) n (I)
O = Ti (-X) p (-OR) q (II)
[Wherein X is a residue obtained by removing H of one OH group from mono- or polyalkanolamine having 2 to 12 carbon atoms, and other OH groups of polyalkanolamine are directly bonded to the same Ti atom. The OH group may be polycondensed in the molecule to form a ring structure, or the OH group directly bonded to another Ti atom may be polycondensed between the molecules to form a repeating structure. The degree of polymerization in the case of forming a repeating structure is 2 or more and 5 or less. R is H or an alkyl group having 1 to 8 carbon atoms which may contain 1 to 3 ether bonds. m is an integer from 1 to 4, n is an integer from 0 to 3, and the sum of m and n is 4. p is an integer from 1 to 2, q is an integer from 0 to 1, and the sum of p and q is 2. When m or p is 2 or more, each X may be the same or different. ]

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