JP2012053321A - Electrophotographic cyan toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic cyan toner containing a cyan coloring agent having durability such as light resistance and ozone resistance and showing excellent coloring power and good color reproducibility at a low lightness and a high lightness, without subjected to a pigmentation process.SOLUTION: The electrophotographic cyan toner contains a tetradentate coordination type phthalocyanine compound having Si or Ge as a central metal and a bidentate coordination type phthalocyanine compound having Mg, Ca, Mn, Fe, Co, Ni, Cu or Zn as a central metal.

Description

  The present invention relates to a cyan toner for electrophotography.

  In recent years, with the widespread use of electrophotographic color image forming apparatuses, their applications have been diversified and demands for image quality have become stricter. In copying an image such as a general photograph, catalog, or map, it is required to reproduce the image very finely and faithfully up to a minute part.

  In addition, the demand for printing an image on a display device for image processing on a CRT display or a liquid crystal display, electronic data submission, personal use, etc. is rapidly expanding, and a standard color space in this field. SRGB (“A Standard Default Color for the Internet-sRGB” by Michael Stokes, Matthew Anderson, Srinivasan Chantraskar, and Richard Mot. There is also a need to be able to.

  However, the color reproduction area in the image formed by yellow, magenta, and cyan color toners does not completely cover the color reproduction area on the computer display screen, so the color reproduction range can be expanded. It is desired.

  In addition, since electrophotographic image forming apparatuses often used for office use are required to have durability such as light resistance and ozone resistance, the selection range of cyan colorants has been particularly limited.

  Examples of cyan colorants that achieve both color reproducibility and durability include C.I. Copper phthalocyanine pigments typified by I Pigment Blue 15.3 have been widely used. However, toners using copper phthalocyanine pigments are excellent in durability, but tend to form aggregated secondary particles and have a tendency to decrease coloring power. Accordingly, as a cyan color for forming a full-color image, color reproducibility is not sufficient, and improvement in color reproducibility of high brightness (light / bright color) is particularly demanded.

  Various technical information is disclosed in order to improve the above problems.

  For example, by using a pigment dispersion technique typified by the solvent method or solvent salt milling method, a means to achieve submicron order pigment dispersion diameter by primary particles without aggregated secondary particles and improve coloring power is proposed. Has been. However, if the pigmentation step as described above is performed after the synthesis step, special mechanical equipment and energy are required for miniaturization, and thus the work load and cost are significantly increased.

  Further, technical information is disclosed that it is effective to use a copper phthalocyanine pigment in combination with another cyan pigment. For example, Patent Document 1 discloses a cyan pigment obtained by wet pulverization of copper phthalocyanine and nickel phthalocyanine in the presence of an inorganic salt and an organic solvent. And a pigment with high coloring power is obtained. Patent Document 2 discloses a phthalocyanine compound having a substituent on a central metal atom and a cyan colorant containing copper phthalocyanine in a specific ratio.

  However, as a result of detailed studies by the present inventors, a cyan toner having excellent coloring power and good color reproducibility has not been obtained even if these techniques are used.

JP 2009-151162 A JP 2009-128750 A

  The present invention has been made in view of the above problems, and its purpose is to have durability such as light resistance and ozone resistance, excellent coloring power, low brightness and high brightness without going through a pigmentation step. An object of the present invention is to provide an electrophotographic cyan toner containing a cyan colorant having good color reproducibility.

  The above object of the present invention is achieved by the following configurations.

  1. An electrophotographic cyan toner comprising a compound represented by the following general formula (1) and a compound represented by the following general formula (2).

(In the formula, M ₁ represents Si or Ge. Z ₁ and Z ₂ represent an alkyl group, an aryl group, a hydroxy group, a halogen atom, an aryloxy group, an alkoxy group, an acyloxy group, or —OSiRaRbRc (where Ra, Rb and Rc each independently, an alkyl group, an aryl group, an alkoxy group, .Z 1 represent any of the groups represented by an aryl _group), Z ₂ is selected from the same or different from each other .R ₁ to R ₈ represents a hydrogen atom, an alkyl group, an aryl group, an alkylsulfonyl group, an alkylsulfamoyl group or —SiRaRbRc (where Ra, Rb and Rc each independently represents an alkyl group, an aryl group, an alkoxy group or an aryloxy group) And R _{1 to} R ₈ may be the same as or different from each other.

(In the formula, M ₂ represents Mg, Ca, Mn, Fe, Co, Ni, Cu or Zn. R _{9 to} R ₁₆ represent a hydrogen atom, an alkyl group, an aryl group, an alkylsulfonyl group, an alkylsulfamoyl group, or -SiRaRbRc (wherein Ra, Rb, and Rc each independently represents an alkyl group, an aryl group, an alkoxy group, or an aryloxy group) R _{9 to} R ₁₆ may be the same as each other. May be different, but not all are hydrogen atoms at the same time.)
2. 2. The electrophotographic cyan toner according to 1, wherein R _{9 to} R ₁₆ in the general formula (2) are hydrogen atoms or alkyl groups having 1 to 5 carbon atoms.

3. In the general formula (2), M ₂ is Zn, Cu, electrophotographic cyan toner according to the 1 or 2, characterized in that any one of Mg.

  According to the present invention, an electrophotography comprising a cyan colorant having durability such as light resistance and ozone resistance, excellent coloring power without undergoing a pigmentation step, and good color reproducibility of low brightness and high brightness. We were able to provide cyan toner for use.

  As a result of intensive studies in view of the above problems, the present inventors have found that a cyan toner for electrophotography containing a compound represented by the general formula (1) having a specific structure and a compound represented by the general formula (2) Cyan for electrophotography containing a cyan colorant that has durability such as light resistance, ozone resistance, etc., has excellent coloring power, and has low lightness and high lightness color reproducibility without going through a pigmentation step It has been found that a toner can be obtained and has reached the present invention.

  The reason why such an effect is manifested is presumed as follows. The compound represented by the general formula (1) has a substituent on the central metal atom, and the compound represented by the general formula (2) has a substituent on the phthalocyanine ring, respectively. Therefore, compared with an unsubstituted copper phthalocyanine pigment. It is considered that the formation of aggregated secondary particles is suppressed and the dispersibility is improved. Moreover, combined use (this invention) of the compound represented by General formula (1) which has a substituent on a central metal atom, and the compound represented by General formula (2) which has a substituent on a phthalocyanine ring, Compared to the combination of the compound represented by the general formula (1) having a substituent on the central metal atom and the phthalocyanine pigment having no substituent on the phthalocyanine ring, the formation of aggregated secondary particles is similarly suppressed. It is considered that dispersibility is improved. In the latter combination, the dispersibility is poor and a pigmentation step is necessary.

  As a result, it is presumed that coloring power close to that of a dye can be obtained while maintaining durability as a pigment. In addition, the compound represented by the general formula (1) and the compound represented by the general formula (2) form a mixed crystal and a similar state at the time of toner preparation, and have a particle size as compared with the case where they are used alone. It is surmised that a smaller pigment contributes.

  The present invention is described in detail below.

  The cyan toner for electrophotography of the present invention contains a compound represented by the general formula (1) and a compound represented by the general formula (2).

[Compounds represented by general formulas (1) and (2)]
In General Formula (1) and General Formula (2), M ₁ and M _{2 each} represent a central metal atom.

Examples of the central metal atom M ₁ in the general formula (1), for example Si, can be exemplified such as Ge, particularly Si is preferred.

Examples of the central metal atom _{M 2} in the general formula (2), exemplified for example Li, Na, K, Mg, Ca, Cr, Mo, Mn, Fe, Co, Ni, Cu, Ag, Au, and Zn, etc. More preferably, Mg, Ca, Mn, Fe, Co, Ni, Cu, and Zn are preferable, and Cu, Zn, and Mg are particularly preferable.

Specific examples of Z ₁ and Z ₂ in the general formula (1) include an alkyl group, an aryl group, a hydroxy group, a halogen atom, an aryloxy group, an alkoxy group, an acyloxy group, or —OSiRaRbRc (where Ra, Rb, and Rc are Each independently represents an alkyl group, an aryl group, an alkoxy group, or an aryloxy group), and these groups may further have a substituent. Z ₁ and Z ₂ may be the same as or different from each other.

Z ₁ and Z ₂ are located in a direction perpendicular to the phthalocyanine ring from the central metal atom M ₁ . In addition, the perpendicular direction here means that it is not on the same plane with respect to the phthalocyanine ring, and it is not essential that the substituent is positioned at exactly 90 ° in the plane.

R _{1 to} R ₁₆ in the general formulas (1) and (2) are each a hydrogen atom, an alkyl group, an aryl group, an alkylsulfonyl group, an alkylsulfamoyl group, or —SiRaRbRc (where Ra, Rb, and Rc are each independently Represents an alkyl group, an aryl group, an alkoxy group, or an aryloxy group). R _{1 to} R ₁₆ may be the same as or different from each other. However, in General Formula (2), all of R _{9 to} R ₁₆ are not simultaneously hydrogen atoms. Moreover, it is preferable that the number of hydrogen atoms is 2-6 among R < ₉ > -R < ₁₆ >, Most preferably, it is 4.

  Specific examples of the substituent include an alkyl group, an aryl group, an alkylsulfonyl group, an alkylsulfamoyl group, -SiRaRbRc (wherein Ra, Rb and Rc are each independently an alkyl group, an aryl group, an alkoxy group, an aryloxy group) Group) and the like. Preferably, it is an alkyl group, and since it is important to suppress aggregation to such an extent that the coloring power is improved without deteriorating light resistance, an alkyl group having 1 to 5 carbon atoms (methyl group, ethyl group, n- Propyl group, i-propyl group, n-butyl group, t-butyl group, t-amyl group, etc.).

  The compounds represented by the general formula (1) and the general formula (2) are, for example, Shirai-Kobayashi, published by IPC Co., Ltd. “Phthalocyanine—Chemistry and Function” (P. 1-62), C. Leznoff-A. B. P. Lever co-authored by VCH and published in 'Phthalogicanes-Properties and Applications' (P. 1-54), etc., can be synthesized by combining quoted or similar methods.

  For example, it can be produced by reacting a phthalonitrile derivative with a metal derivative. Alternatively, the target product can be obtained by using an isoindolediimine derivative, a phthalic anhydride derivative, a phthalimide derivative, or the like instead of the phthalonitrile derivative.

The metal derivative is not particularly limited as long as it is a derivative containing central metal atoms M ₁ and M ₂ in general formula (1) and general formula (2). Specific examples include halides, carboxylic acid derivatives, alcohol derivatives, sulfates, nitrates and the like. The amount of the metal derivative and phthalonitrile derivative used in the synthesis is preferably in the range of 1: 2 to 1: 6 in terms of molar ratio.

  The synthesis reaction is preferably performed in the presence of a suitable solvent. As the solvent at this time, an organic solvent having a boiling point of 110 ° C. or higher is preferably used. For example, toluene, chlorobenzene, dichlorobenzene, trichlorobenzene, nitrobenzene, quinoline, chloronaphthalene, n-amyl alcohol, n-hexanol, cyclohexanol, 2-methyl-1-pentanol, 1-heptanol, 2-heptanol, 1- Examples include, but are not limited to, octanol, 2-ethylhexanol, benzyl alcohol, ethylene glycol, propylene glycol, ethoxyethanol, propoxyethanol, butoxyethanol, dimethylaminoethanol, diethylaminoethanol, sulfolane and the like. The amount of the solvent used for the synthesis can be 1 to 100 times by mass, preferably 5 to 20 times by mass, such as phthalonitrile derivatives.

  If necessary, urea or ammonium molybdate may be added. The addition amount can be 0.1 to 10 times mol, preferably 0.5 to 2 times mol, per 1 mol of the intermediate phthalonitrile derivative and the like.

  The reaction temperature is 80 to 300 ° C, preferably 110 to 230 ° C. If it is less than 80 degreeC, reaction may become extremely slow, and when it exceeds 300 degreeC, the target object may decompose | disassemble. The reaction time can be 2 to 20 hours, preferably 5 to 15 hours. If it is less than 2 hours, there are many unreacted raw materials, and if it exceeds 20 hours, the target product may be decomposed.

The compounds represented by the general formula (1) and the general formula (2) inevitably have a substituent Rn (in the general formula (1), R _{1 to} R ₈ , in the general formula (2) , R _{9 to} R ₁₆ ) may include substitution position isomers, and these substitution position isomers are regarded as the same compound without being distinguished from each other.

  Although the specific example of a compound represented by General formula (1) below is given, it is not limited to these.

  Although the specific example of a compound represented by General formula (2) below is given, it is not limited to these.

(Cyan colorant)
The cyan colorant according to the present invention is characterized by containing a compound represented by the general formula (1) and a compound represented by the general formula (2).

  The ratio mA: mB of the content of the compound represented by the general formula (1) and the compound represented by the general formula (2) is not particularly limited, but is preferably in the range of 90:10 to 50:50. This is because, in the above range, the balance of color developability in the low brightness and high brightness cyan regions is particularly excellent.

  For the purpose of adjusting the color tone, conventionally known pigments and dyes may be further used in combination. Although not limited to the following, C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 16, C.I. I. Pigment blue 60, C.I. I. And CI Pigment Green 7.

  The content of the cyan colorant is preferably 2 to 12% by mass, more preferably 4 to 8% by mass, based on the entire cyan toner particles.

(Yellow colorant)
As the yellow colorant constituting the yellow toner, conventionally known pigments and dyes can be used, and a single or a plurality of them can be selected and used as desired.

  Although a specific example is given below, it is not limited to this. Examples of the pigment include C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 155, C.I. I. Pigment yellow 156, C.I. I. Pigment yellow 180, C.I. I. And CI Pigment Yellow 185. Examples of the dye include C.I. I. Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162 and the like. The content of the yellow colorant is preferably 2 to 12% by mass, more preferably 4 to 8% by mass with respect to the entire yellow toner particles.

(Magenta colorant)
As the magenta colorant constituting the magenta toner, conventionally known pigments and dyes can be used, and a single or a plurality can be selected and used as desired.

  Although a specific example is given below, it is not limited to this. Examples of the pigment include C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 166, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. And CI Pigment Red 222. Examples of the dye include C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 122 and the like. In addition, azomethine dyes and indoaniline dyes derived from couplers such as cyclic methylene compounds such as phenol, naphthols, pyrazolone and pyrazolotriazole, and open-chain methylene compounds are also preferably used. The content of the magenta colorant is preferably 2 to 12% by mass, more preferably 4 to 8% by mass with respect to the entire magenta toner particles.

(Black colorant)
Conventionally known pigments and dyes can be used as the black colorant constituting the black toner.

  Although a specific example is given below, it is not limited to this. Examples of the pigment include carbon black such as furnace black, channel black, acetylene black, thermal black, and lamp black, and magnetic powder such as magnetite and ferrite.

  These inorganic pigments can be used alone or in combination as required. The addition amount of the pigment is 2 to 20% by mass with respect to the whole black toner, and preferably 3 to 15% by mass is selected.

  When used as a magnetic toner, the above-mentioned magnetite can be added. In this case, it is preferable to add 20 to 60% by mass in the toner from the viewpoint of imparting predetermined magnetic properties.

(Surface modifier)
The colorant (colorant particles) constituting the toner of the present invention may be surface-modified. A conventionally well-known thing can be used as a surface modifier, Specifically, a silane coupling agent, a titanium coupling agent, an aluminum coupling agent etc. can be used preferably. Examples of the silane coupling agent include alkoxysilanes such as methyltrimethoxysilane, phenyltrimethoxysilane, methylphenyldimethoxysilane, and diphenyldimethoxysilane, siloxanes such as hexamethyldisiloxane, γ-chloropropyltrimethoxysilane, vinyltrimethyl. Chlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-ureido Examples thereof include propyltriethoxysilane. Examples of titanium coupling agents include TTS, 9S, 38S, 41B, 46B, 55, 138S, and 238S, which are commercially available under the trade name “Plenact” manufactured by Ajinomoto Co., Inc., and commercial products A manufactured by Nippon Soda Co., Ltd. -1, B-1, TOT, TST, TAA, TAT, TLA, TOG, TBSTA, A-10, TBT, B-2, B-4, B-7, B-10, TBSTA-400, TTS, TOA -30, TSDMA, TTAB, TTOP and the like. Examples of the aluminum coupling agent include “Plenact AL-M” manufactured by Ajinomoto Co., Inc.

  The addition amount of these surface modifiers is preferably 0.01 to 20% by mass, more preferably 0.1 to 5% by mass with respect to the colorant.

  Examples of the method for modifying the surface of the colorant particles include a method in which a surface modifier is added to the dispersion of the colorant particles and this system is heated to react.

  The surface-modified colorant particles are collected by filtration, washed with the same solvent and filtered, and then dried.

(Silanol compound)
The toner used in the present invention preferably contains a silanol compound.

  As examples of the silanol compound, compounds described in [Chemical Formula 12] and [Chemical Formula 13] of JP-A No. 2009-265227 are preferable. The use amount and addition method in the electrophotographic cyan toner of the present invention are also the same as in JP-A-2009-265227.

  The silanol compound according to the present invention can be easily synthesized by a person having knowledge in the field according to a known method, or can be obtained as a commercial product. For example, JP-A-63-22759, JP-A-63-316789, JP-A-63-5093, JP-A-3-157388, JP-A-6-256355, JP-A-8-143581, JP-A-2002-20390, etc. Is cited as a reference.

  The content of the silanol compound is not particularly limited, but is preferably 100 to 500 ppm, and more preferably 100 to 350 ppm with respect to the electrostatic image developing toner. By setting the content of the organic silanol compound according to the present invention to 100 ppm or more, the objective effect of the present invention can be exhibited, and by setting it to 500 ppm or less, the electrostatic charge image developing toner does not become too soft, The toner storage stability is deteriorated, the fixing rate is lowered, or odor is not a problem, which is preferable.

  The addition amount in the production process of the silanol compound is preferably 100 to 350 ppm with respect to the electrostatic image developing toner, and by setting the addition amount within this range, the release agent (wax) in the toner is added. The effect of improving dispersibility can be exhibited, and the residual amount of silanol compound in the toner after drying under reduced pressure can be set within the range specified in the present invention, but is not limited thereto.

  As a method for adding the silanol compound to the toner for developing an electrostatic image, for example, in the case of a polymerization toner including a step of polymerizing the following polymerizable monomer in an aqueous medium to produce a resin, silanol Although the method of adding a compound at the time of preparation of a colorant dispersion liquid is preferable, the method of adding to a polymerizable monomer at the time of resin particle preparation is also mentioned. When the production method of the polymerization method toner is the following multistage polymerization method, a method of adding at the same time as the addition of the release agent is also mentioned.

  In the present invention, the silanol compound is quantified by a head space type gas chromatograph using a detection method used in a normal gas chromatograph such as an internal standard method. In this method, toner is sealed in an open / close container, heated at the time of thermal fixing of a copying machine, etc., and the container is filled with volatile components, and the gas in the container is quickly injected into the gas chromatograph for volatilization. In addition to measuring the amount of components, MS (mass spectrometry) is also performed.

  Below, the measuring method by a head space gas chromatograph is demonstrated in detail.

<Headspace gas chromatograph measurement method>
1. Sample collection A 0.8 g sample is collected in a 20 ml headspace vial. The sample amount is weighed to 0.01 g (necessary for calculating the area per unit mass). The vial is sealed with a septum using a dedicated crimper.
2. Heating the sample Place the sample in a 170 ° C constant temperature bath and heat for 30 minutes.
3. Setting of gas chromatographic separation conditions A column coated with silicon oil SE-30 so as to have a mass ratio of 15% and packed in a column having an inner diameter of 3 mm and a length of 3 m is used as a separation column. The separation column is attached to a gas chromatograph, and He is used as a carrier to flow at 50 ml / min. The temperature of the separation column is set to 40 ° C., and measurement is performed while the temperature is increased to 260 ° C. at 15 ° C./min. Hold for 5 minutes after reaching 260 ° C.
4). Introduction of sample The vial bottle is taken out from the thermostatic chamber, immediately 1 ml of gas generated from the sample is collected with a gas tight syringe, and this is injected into the separation column.
5). Calculation A calibration curve is prepared in advance using the silanol compound used as the internal reference substance, and the concentration of each component is determined.
6). Equipment (1) Headspace conditions Headspace device HP 7694 “Head Space Sampler” manufactured by Hewlett-Packard Company
Temperature condition transfer line: 200 ° C
Loop temperature: 200 ° C
Sample amount: 0.8 g / 20 ml vial (2) GC / MS condition GC: HP5890 manufactured by Hewlett-Packard Company
MS: HP5971 manufactured by Hewlett-Packard Company
Column: HP-624 30m x 0.25mm
Oven temperature: 40 ° C (3min) -15 ° C / min-260 ° C
Measurement mode: SIM
(Image stabilizer)
In order to improve the storage stability of the colorant, as an image stabilizer, for example, a compound described and cited on pages 10 to 13 of JP-A-8-29934 may be added. Examples include amine-based, sulfur-based, and phosphorus-based compounds.

  For the same purpose, for example, an organic ultraviolet absorber or an inorganic ultraviolet absorber may be added as an ultraviolet absorber.

  Examples of organic ultraviolet absorbers include 2- (2′-hydroxy-5′-t-butylphenyl) benzotriazole and 2- (2′-hydroxy-3 ′, 5′-di-t-butylphenyl) benzotriazole. Benzotriazole compounds such as 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octyloxybenzophenone, etc., phenyl salsylate, 4-t-butylphenyl salsylate, 2, Hydroxybenzoate systems such as 5-t-butyl-4-hydroxybenzoic acid n-hexadecyl ester, 2,4-di-t-butylphenyl-3 ', 5'-di-t-butyl-4'-hydroxybenzoate Compounds and the like.

  Examples of inorganic ultraviolet absorbers include titanium oxide, zinc oxide, cerium oxide, iron oxide, and barium sulfate. Organic ultraviolet absorbers are preferred, and ultraviolet absorbers include 50% transmittance. The wavelength of is preferably 350 to 420 nm, more preferably 360 to 400 nm. When the wavelength is lower than 350 nm, the ultraviolet blocking ability is weak, and when the wavelength is higher than 420 nm, the coloring becomes strong. Although there is no restriction | limiting in particular about addition amount, The range of 10-200 mass% is preferable with respect to a pigment | dye, and 50-150 mass% is more preferable. It is also preferable to use these in combination.

[Toner Production Method]
The method for producing the electrophotographic cyan toner of the present invention is not particularly limited. It can be prepared by a kneading method, a pulverizing method, a pulverizing method for producing a toner through a classification step, a polymerization method for polymerizing a polymerizable monomer, and simultaneously forming particles while controlling the shape and size. The polymerization method is more preferable. In this production method, a polymerizable monomer is polymerized by a suspension polymerization method to prepare resin particles, or the monomer is added in a liquid (in an aqueous medium) to which an emulsion of necessary additives is added. Emulsion polymerization or mini-emulsion polymerization is performed to prepare fine resin particles. If necessary, charge control resin particles are added, and then the resin particles are aggregated by adding a coagulant such as an organic solvent or salts. It is manufactured by the method of fusing.

<Suspension polymerization method>
As an example of the method for producing the electrophotographic cyan toner of the present invention, a charge controllable resin is dissolved in a polymerizable monomer, a colorant, if necessary, a release agent, and various polymerization initiators. A constituent material is added, and various constituent materials are dissolved or dispersed in the polymerizable monomer using a homogenizer, a sand mill, a sand grinder, an ultrasonic disperser, or the like. The polymerizable monomer in which these various constituent materials are dissolved or dispersed is dispersed in an aqueous medium containing a dispersion stabilizer using a homomixer, a homogenizer, or the like to obtain oil droplets of a desired size as an electrophotographic cyan toner. To disperse. Thereafter, the stirring mechanism is transferred to a reaction device (stirring device) which is a stirring blade described later, and the polymerization reaction is advanced by heating. After completion of the reaction, the dispersion stabilizer is removed, filtered, washed, and dried to prepare the toner of the present invention. In the present invention, the “aqueous medium” refers to a medium containing at least 50% by mass of water.

<Emulsion polymerization method>
Further, as another method for producing the electrophotographic cyan toner of the present invention, a method in which resin particles are prepared by salting out / fusion in an aqueous medium is preferable. The method is not particularly limited, and examples thereof include methods described in JP-A Nos. 5-265252, 6-329947, and 9-15904. That is, a method of salting out, agglomerating, and fusing a plurality of fine particles composed of resin particles and colorants, or dispersed particles of resin, colorants, and the like, particularly in water using an emulsifier Later, a coagulant with a critical coagulation concentration or higher is added for salting out, and at the same time, the particle size is gradually grown while forming a fused particle by heating and fusing above the glass transition temperature of the formed polymer itself, When the target particle size is reached, a large amount of water is added to stop particle size growth, and the shape is controlled by smoothing the particle surface while heating and stirring, and the particles are heated and dried in a fluid state while containing water. By doing so, the toner of the present invention can be formed. Here, a solvent that dissolves infinitely in water such as alcohol may be added simultaneously with the flocculant.

  In the method for producing the cyan toner for electrophotography of the present invention, the composite resin fine particles and the colorant particles formed through the step of polymerizing the polymerizable monomer after dissolving the crystalline substance in the polymerizable monomer are used. A salting-out / fusion method is preferably used. When the crystalline substance is dissolved in the polymerizable monomer, the crystalline substance may be dissolved and dissolved, or may be melted and dissolved.

  In addition, as a method for producing the cyan toner for electrophotography of the present invention, a step of salting out / fusing composite resin fine particles and colorant particles obtained by a multistage polymerization method is preferably used. Here, the multistage polymerization method will be described below.

(Method for producing composite resin particles obtained by multistage polymerization method)
When the multistage polymerization method is used, it is preferable that the method for producing the cyan toner for electrophotography of the present invention includes the following steps.
1: Multi-stage polymerization step 2: Salting out / fusing step of salting out / fusing composite resin particles and colorant particles to obtain toner particles 3: Filtering off the toner particles from a dispersion system of toner particles, Filtration / washing step 4 for removing the surfactant and the like from the toner particles: a drying step for drying the washed toner particles;
5: Consists of a step of adding an external additive to the dried toner particles.

  Hereinafter, each step will be described in detail.

[Multi-stage polymerization process]
The multi-stage polymerization step is a polymerization method performed to expand the molecular weight distribution of the resin particles so as to obtain a toner in which offset generation is prevented. That is, in order to form phases having different molecular weight distribution in one resin particle, the polymerization reaction is performed in multiple stages, and the obtained resin particle has a molecular weight gradient from the center of the particle toward the surface layer. It is intended to be formed. For example, a method of forming a low molecular weight surface layer by first obtaining a high molecular weight resin particle dispersion and then newly adding a polymerizable monomer and a chain transfer agent is employed.

  In the present invention, it is preferable to employ a multi-stage polymerization method of three-stage polymerization or more from the viewpoint of production stability and crushing strength of the resulting toner. Hereinafter, a two-stage polymerization method and a three-stage polymerization method, which are representative examples of the multistage polymerization method, will be described. The toner obtained by such a multistage polymerization reaction preferably has a lower molecular weight as the surface layer from the viewpoint of crushing strength.

<Two-stage polymerization method>
The two-stage polymerization method is a method for producing composite resin particles composed of a central portion (core) formed from a high molecular weight resin containing a crystalline substance and an outer layer (shell) formed from a low molecular weight resin. is there.

  This method will be described in detail. First, a crystalline substance is dissolved in a monomer to prepare a monomer solution, and the monomer solution is added to oil droplets in an aqueous medium (for example, a surfactant aqueous solution). After the dispersion, this system is polymerized (first stage polymerization) to prepare a dispersion of high molecular weight resin particles containing a crystalline substance.

  Next, a polymerization initiator and a monomer for obtaining a low molecular weight resin are added to the dispersion of the resin particles, and the monomer is polymerized in the presence of the resin particles (second stage polymerization). In this method, a coating layer made of a low molecular weight resin (monomer polymer) is formed on the surface of the resin particles.

<Three-stage polymerization method>
The three-stage polymerization method produces composite resin particles composed of a central part (core) formed from a high molecular weight resin, an intermediate layer containing a crystalline substance, and an outer layer (shell) formed from a low molecular weight resin. Is the method. The toner of the present invention exists as the composite resin particles as described above.

  This method will be specifically described. First, a dispersion of resin particles obtained by a polymerization process (first-stage polymerization) according to a conventional method is added to an aqueous medium (for example, an aqueous solution of a surfactant). In the aqueous medium, a monomer solution obtained by dissolving a crystalline substance in a monomer is dispersed in oil droplets, and then this system is polymerized (second-stage polymerization) to obtain resin particles (cores). A coating layer (intermediate layer) made of a resin (monomer polymer) containing a crystalline substance is formed on the surface of the particles, and a dispersion of composite resin particles (high molecular weight resin-intermediate molecular weight resin) is prepared. Prepare.

  Next, a polymerization initiator and a monomer for obtaining a low molecular weight resin are added to the obtained dispersion of composite resin particles, and the monomer is polymerized in the presence of the composite resin particles (third-stage polymerization). ), A coating layer made of a low molecular weight resin (monomer polymer) is formed on the surface of the composite resin particles. In the above method, the incorporation of the intermediate layer is preferable because the crystalline substance can be finely and uniformly dispersed.

  In one embodiment of the method for producing a cyan toner for electrophotography of the present invention, a polymerizable monomer is polymerized in an aqueous medium. That is, when forming resin particles (core particles) or a coating layer (intermediate layer) containing a crystalline substance, the crystalline substance is dissolved in the monomer, and the resulting monomer solution is oiled in an aqueous medium. It is a method of obtaining latex particles by dispersing in drops and adding a polymerization initiator to this system for polymerization treatment.

  The aqueous medium used in the present invention refers to a medium comprising 50 to 100% by mass of water and 0 to 50% by mass of a water-soluble organic solvent. Examples of the water-soluble organic solvent include methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, tetrahydrofuran, and the like, and an alcohol-based organic solvent that does not dissolve the obtained resin is preferable.

  As a suitable polymerization method for forming resin particles or a coating layer containing a crystalline substance, the crystalline substance is a monomer in an aqueous medium in which a surfactant having a concentration equal to or lower than the critical micelle concentration is dissolved. The monomer solution dissolved in is dispersed in oil droplets using mechanical energy to prepare a dispersion, and a water-soluble polymerization initiator is added to the resulting dispersion to cause radical polymerization in the oil droplets. A method (hereinafter referred to as “mini-emulsion method” in the present invention), and the effects of the present invention can be exhibited more preferably. In the above method, an oil-soluble polymerization initiator may be used instead of or together with the water-soluble polymerization initiator.

  According to the mini-emulsion method that mechanically forms oil droplets, unlike the usual emulsion polymerization method, there is little detachment of the crystalline substance dissolved in the oil phase, and it is sufficient in the resin particles or coating layer to be formed. Any amount of crystalline material can be introduced.

  Here, the disperser for dispersing oil droplets by mechanical energy is not particularly limited. For example, a stirring device “CLEARMIX” (M Technique (Equation Technique) equipped with a rotor that rotates at high speed is used. Co., Ltd.), ultrasonic disperser, mechanical homogenizer, manton gorin, pressure homogenizer, and the like. Moreover, as a dispersed particle diameter, 10-1000 nm is preferable, More preferably, it is 50-1000 nm, Most preferably, it is 30-300 nm.

  By giving a distribution to the dispersed particle diameter, the phase separation structure of the crystalline substance in the toner particles, that is, the ferret horizontal diameter, the shape factor, and the coefficient of variation thereof may be controlled.

  In addition, as other polymerization methods for forming resin particles or a coating layer containing a crystalline substance, known methods such as an emulsion polymerization method, a suspension polymerization method, and a seed polymerization method can be employed. These polymerization methods can also be employed to obtain resin particles (core particles) or coating layers constituting the composite resin particles that do not contain a crystalline substance.

  The particle diameter of the composite resin particles obtained in this polymerization step is in the range of 10 to 1000 nm in terms of mass average particle diameter measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.). Is preferred.

  Moreover, it is preferable that the glass transition temperature (Tg) of a composite resin particle exists in the range of 48-74 degreeC, More preferably, it is 52-64 degreeC.

  The softening point of the composite resin particles is preferably in the range of 95 to 140 ° C.

  The cyan toner for electrophotography of the present invention is obtained by fusing resin particles to the surface of the resin and colored particles by a salting-out / fusing method to form a resin layer. explain.

[Salting out / fusion process]
This salting-out / fusion step is carried out by salting out / bonding the composite resin particles and the colorant particles obtained in the multi-stage polymerization step (to cause salting-out and fusion at the same time) to form an irregular shape ( This is a step of obtaining non-spherical toner particles.

  In the present invention, salting out / fusion means that salting out (aggregation of particles) and fusion (disappearance of the interface between particles) occur simultaneously or salting out and fusion occur simultaneously. . In order to perform salting-out and fusion at the same time, it is preferable to agglomerate particles (composite resin particles, colorant particles) under a temperature condition higher than the glass transition temperature (Tg) of the resin constituting the composite resin particles. .

  In this salting-out / fusion process, internal additive particles such as charge control agents (fine particles having a number average primary particle size of about 10 to 1000 nm) may be salted out / fused together with the composite resin particles and the colorant particles. Good. The colorant particles may be surface-modified, and conventionally known ones can be used as the surface modifier.

[Aging process]
The aging step is a step subsequent to the salting-out / fusion step, and after the resin particles are fused, the temperature is kept near the melting point of the crystalline substance, preferably the melting point ± 20 ° C., and stirring is continued at a constant strength. This is a step of phase-separating the crystalline substance. In this step, it is possible to control the ferret horizontal diameter, shape factor, and variation coefficient of the crystalline material.

  Moreover, in this invention, it is preferable that the total value of the bivalent (trivalent) metal element used for a coagulant | flocculant and the monovalent | monohydric metal element added as an aggregation terminator mentioned later is 350-35000 ppm. The residual amount of metal ions in the toner can be measured by using a fluorescent X-ray analyzer “System 3270” (manufactured by Rigaku Denki Kogyo Co., Ltd.) and using a metal species of a metal salt used as a flocculant (for example, calcium chloride). It can be determined by measuring the intensity of the fluorescent X-ray emitted from the derived calcium or the like. As a specific measurement method, a plurality of toners having a known content ratio of the flocculant metal salt are prepared, each toner 5g is pelletized, the content ratio (mass ppm) of the flocculant metal salt, and the metal species of the metal salt The relationship (calibration curve) with the fluorescent X-ray intensity (peak intensity) is measured. Next, the toner (sample) whose content of the flocculant metal salt is to be measured is similarly pelletized, and the fluorescent X-ray intensity from the metal species of the flocculant metal salt is measured. Amount "can be determined.

[Filtering and washing process]
In this filtration / washing step, a filtration treatment for filtering the toner particles from the toner particle dispersion obtained in the above step, and a surfactant or salt from the filtered toner particles (cake-like aggregate). A cleaning process for removing deposits such as a depositing agent is performed. Here, the filtration method is not particularly limited, such as a centrifugal separation method, a vacuum filtration method using Nutsche or the like, a filtration method using a filter press or the like.

[Drying process]
This step is a step of drying the washed toner particles, but in the present invention, a step of drying under reduced pressure is preferred.

  Examples of the vacuum dryer used in this step include, but are not limited to, a vacuum spray dryer, a vacuum freeze dryer, and a vacuum dryer. Specifically, it is preferable to use a stationary shelf dryer, a movable shelf dryer, a fluidized bed dryer, a rotary dryer, a stirring dryer, or the like that can be decompressed.

  The conditions for drying under reduced pressure may be any temperature as long as the drying temperature is equal to or lower than the Tg of the resin used in the toner, and the degree of reduced pressure, the drying time, and the like are not particularly limited and can be set as appropriate.

  In addition, when the toner particles subjected to the drying under reduced pressure are aggregated by weak interparticle attractive force, the aggregate may be crushed. Here, as the crushing treatment apparatus, a mechanical crushing apparatus such as a jet mill, a Henschel mixer, a coffee mill, or a food processor can be used.

  The cyan toner for electrophotography of the present invention forms composite resin particles in the absence of a colorant, adds a dispersion of colorant particles to a dispersion of the composite resin particles, and combines the composite resin particles, the colorant particles, It is preferable to prepare by salting out / fusion.

  Thus, the polymerization reaction for obtaining the composite resin particles is not inhibited by preparing the composite resin particles in a system in which no colorant is present. Therefore, according to the cyan toner for electrophotography of the present invention, excellent anti-offset property is not impaired, and contamination of the fixing device and image smear due to toner accumulation are not caused.

  In addition, as a result of the polymerization reaction for obtaining the composite resin particles being reliably performed, no monomer or oligomer remains in the obtained toner particles, and the heat fixing step of the image forming method using the toner In this case, no odor is generated.

  Furthermore, since the surface characteristics of the obtained toner particles are uniform and the charge amount distribution is sharp, an image with excellent sharpness can be formed over a long period of time. According to such a toner having a uniform composition, molecular weight, and surface characteristics between toner particles, an image forming method including a fixing process using a contact heating method maintains good adhesion (high fixing strength) to an image support. However, it is possible to improve the offset resistance and the anti-winding property, and an image having an appropriate gloss can be obtained.

  Next, each component used in the toner manufacturing process will be described in detail.

(Polymerizable monomer)
As a polymerizable monomer for producing the resin (binder) used in the present invention, a hydrophobic monomer is an essential constituent, and a crosslinkable monomer is used as necessary. Moreover, it is desirable to contain at least one monomer having an acidic polar group or a monomer having a basic polar group as described below.

(1) Hydrophobic monomer As a hydrophobic monomer which comprises a monomer component, it does not specifically limit and a conventionally well-known monomer can be used. Moreover, it can be used combining 1 type (s) or 2 or more types so that the required characteristic may be satisfy | filled.

  Specifically, monovinyl aromatic monomers, (meth) acrylic acid ester monomers, vinyl ester monomers, vinyl ether monomers, monoolefin monomers, diolefin monomers , Halogenated olefin monomers and the like can be used.

  Examples of vinyl aromatic monomers include styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, p-methoxy styrene, p-phenyl styrene, p-chloro styrene, p-ethyl styrene, p. -N-butyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, 2, Examples thereof include styrene monomers such as 4-dimethylstyrene and 3,4-dichlorostyrene and derivatives thereof.

  Examples of acrylic monomers include acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl acrylate, methyl methacrylate, methyl methacrylate, methacrylic acid. Examples include butyl acid, hexyl methacrylate, 2-ethylhexyl methacrylate, ethyl β-hydroxyacrylate, propyl γ-aminoacrylate, stearyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, and the like.

  Examples of vinyl ester monomers include vinyl acetate, vinyl propionate, and vinyl benzoate.

  Examples of the vinyl ether monomer include vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, vinyl phenyl ether and the like.

  Examples of the monoolefin monomer include ethylene, propylene, isobutylene, 1-butene, 1-pentene, 4-methyl-1-pentene and the like.

  Examples of the diolefin monomer include butadiene, isoprene, chloroprene and the like.

(2) Crosslinkable monomer A crosslinkable monomer may be added to improve the properties of the resin particles. Examples of the crosslinkable monomer include those having two or more unsaturated bonds such as divinylbenzene, divinylnaphthalene, divinyl ether, diethylene glycol methacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, and diallyl phthalate.

(3) Monomer having an acidic polar group Monomers having an acidic polar group include (a) an α, β-ethylenically unsaturated compound having a carboxyl group (—COOH) and (b) a sulfone group (— Mention may be made of α, β-ethylenically unsaturated compounds having SO ₃ H).

  Examples of the α, β-ethylenically unsaturated compound (a) having a —COO group include acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, cinnamic acid, maleic acid monobutyl ester, maleic acid. Examples thereof include acid monooctyl esters and metal salts thereof such as Na and Zn.

Examples of the α, β-ethylenically unsaturated compound having a —SO ₃ H group in (b) include sulfonated styrene, its Na salt, allylsulfosuccinic acid, octyl allylsulfosuccinate, and its Na salt. .

(4) Monomer having a basic polar group As the monomer having a basic polar group, (i) 1-12 carbon atoms having an amine group or a quaternary ammonium group, preferably 2-8, particularly preferably 2. (Meth) acrylic acid esters of aliphatic alcohols, (ii) (meth) acrylic acid amides or (meth) acrylic acid amides optionally monosubstituted or disubstituted with alkyl groups of 1 to 18 carbon atoms on N, (iii) Examples thereof include a vinyl compound substituted with a heterocyclic group having N as a ring member and (iv) N, N-diallyl-alkylamine or a quaternary ammonium salt thereof. Among them, (i) aliphatic alcohol (meth) acrylic acid ester having an amine group or quaternary ammonium group is preferable as a monomer having a basic polar group.

  Examples of (meth) acrylic acid esters of aliphatic alcohols having an amine group or quaternary ammonium group (i) include dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, and the above four compounds. A quaternary ammonium salt, 3-dimethylaminophenyl acrylate, 2-hydroxy-3-methacryloxypropyltrimethylammonium salt, etc. can be mentioned.

  (Ii) (Meth) acrylic acid amide or optionally mono- or dialkyl-substituted (meth) acrylic acid amide on N includes acrylamide, N-butylacrylamide, N, N-dibutylacrylamide, piperidylacrylamide, methacrylamide, N-butylmethacrylamide, N, N-dimethylacrylamide, N-octadecylacrylamide and the like can be mentioned.

  Examples of the vinyl compound substituted with a heterocyclic group having N as a ring member in (iii) include vinylpyridine, vinylpyrrolidone, vinyl-N-methylpyridinium chloride, vinyl-N-ethylpyridinium chloride and the like.

  Examples of (iv) N, N-diallyl-alkylamine include N, N-diallylmethylammonium chloride and N, N-diallylethylammonium chloride.

(Polymerization initiator)
The radical polymerization initiator used in the present invention can be appropriately used as long as it is water-soluble. For example, persulfates (for example, potassium persulfate, ammonium persulfate, etc.), azo compounds (for example, 4,4′-azobis-4-cyanovaleric acid and its salts, 2,2′-azobis (2-amidinopropane) Salt), peroxide compounds and the like. Furthermore, the radical polymerization initiator can be combined with a reducing agent as necessary to form a redox initiator. Use of a redox initiator is preferable because the polymerization activity increases, the polymerization temperature can be lowered, and the polymerization time can be shortened.

  As the polymerization temperature, any temperature may be selected as long as it is equal to or higher than the lowest radical generation temperature of the polymerization initiator. However, it is possible to perform polymerization at room temperature or higher by using a polymerization initiator that starts at room temperature, for example, a combination of hydrogen peroxide and a reducing agent (ascorbic acid or the like).

(Surfactant)
In particular, in order to perform miniemulsion polymerization using the above-described polymerizable monomer, it is preferable to disperse oil droplets in an aqueous medium using a surfactant. The surfactant that can be used in this case is not particularly limited, and the following ionic surfactants can be given as examples of suitable compounds.

  Examples of the ionic surfactant include sulfonate (sodium dodecylbenzenesulfonate, sodium arylalkylpolyethersulfonate, 3,3-disulfonediphenylurea-4,4-diazo-bis-amino-8-naphthol- 6-sulfonate sodium, ortho-carboxybenzene-azo-dimethylaniline, 2,2,5,5-tetramethyl-triphenylmethane-4,4-diazo-bis-β-naphthol-6-sulfonate sodium, etc.) , Sulfate salts (sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, etc.), fatty acid salts (sodium oleate, sodium laurate, sodium caprate, sodium caprylate, sodium caproate, stearyl Potassium, calcium oleate and the like).

  Nonionic surfactants can also be used. Specifically, for example, polyethylene oxide, polypropylene oxide, a combination of polypropylene oxide and polyethylene oxide, ester of polyethylene glycol and higher fatty acid, alkylphenol polyethylene oxide, ester of higher fatty acid and polyethylene glycol, ester of higher fatty acid and polypropylene oxide, Examples include sorbitan esters.

  In the present invention, these surfactants are mainly used as an emulsifier during emulsion polymerization, but may be used for other steps or for other purposes.

(Molecular weight distribution of resin particles and toner)
The toner of the present invention preferably has a peak or shoulder at 100,000 to 1,000,000 and 1,000 to 50,000, and further has a peak or shoulder of 100,000 to 1,000,000, More preferably, it is present at 25,000 to 150,000 and 1,000 to 50,000.

  The molecular weight of the resin particles is both a high molecular weight component having a peak or shoulder in the region of 100,000 to 1,000,000 and a low molecular weight component having a peak or shoulder in the region of 1,000 to less than 50,000. A resin containing at least is preferable. More preferably, an intermediate molecular weight resin having a peak or shoulder at a peak molecular weight of 15,000 to 100,000 is preferably used.

  The molecular weight measurement method of the toner or resin is preferably measured by GPC (gel permeation chromatography) using THF (tetrahydrofuran) as a solvent. That is, 1.0 ml of THF is added to 0.5 to 5 mg of a measurement sample, more specifically 1 mg, and the mixture is sufficiently dissolved by stirring at room temperature using a magnetic stirrer or the like. Subsequently, after processing with a membrane filter having a pore size of 0.45 to 0.50 μm, the solution is injected into GPC. The measurement conditions of GPC are measured by stabilizing the column at 40 ° C., flowing THF at a flow rate of 1.0 ml / min, and injecting about 100 μl of a sample having a concentration of 1 mg / ml. The column is preferably used in combination with a commercially available polystyrene gel column. For example, combinations of Shodex GPC KF-801, 802, 803, 804, 805, 806, and 807 manufactured by Showa Denko KK, and TSKgel G1000H, G2000H, G3000H, G4000H, G5000H, G6000H, G7000H, and TSKguard column manufactured by Tosoh Corporation Etc. As a detector, a refractive index detector (IR detector) or a UV detector may be used. In the measurement of the molecular weight of a sample, the molecular weight distribution of the sample is calculated using a calibration curve created using monodisperse polystyrene standard particles. About 10 points may be used as polystyrene for preparing a calibration curve.

(Flocculant)
The flocculant used in the present invention is preferably selected from metal salts.

  Examples of the metal salt include monovalent metals such as alkali metal salts such as sodium, potassium and lithium, divalent metals such as alkaline earth metal salts such as calcium and magnesium, and divalent metals such as manganese and copper. Examples thereof include trivalent metal salts such as salts, iron and aluminum.

  Specific examples of these metal salts are shown below. Specific examples of the monovalent metal salt include sodium chloride, potassium chloride, lithium chloride, and divalent metal salts such as calcium chloride, zinc chloride, copper sulfate, magnesium sulfate, and manganese sulfate. Examples of the trivalent metal salt include aluminum chloride and iron chloride. These are appropriately selected according to the purpose. In general, a divalent metal salt has a smaller critical aggregation concentration (coagulation value or coagulation point) than a monovalent metal salt, and a trivalent metal salt has a smaller critical aggregation concentration.

  The critical flocculation concentration referred to in the present invention is an index related to the stability of the dispersion in the aqueous dispersion, and indicates the concentration at which flocculation occurs when a flocculant is added. This critical coagulation concentration varies greatly depending on the latex itself and the dispersant. For example, it is described in Seizo Okamura et al., Polymer Chemistry 17,601 (1960), etc., and according to these descriptions, the value can be known. As another method, a desired salt is added to the target particle dispersion at different concentrations, the ζ potential of the dispersion is measured, and the salt concentration at the point where the ζ potential changes is determined as the critical aggregation concentration. It is also possible.

  In the present invention, the polymer fine particle dispersion is treated with a metal salt so as to have a concentration equal to or higher than the critical aggregation concentration. At this time, as a matter of course, whether the metal salt is added directly or as an aqueous solution is arbitrarily selected according to the purpose. When added as an aqueous solution, the added metal salt must be equal to or higher than the critical aggregation concentration of the polymer particles with respect to the volume of the polymer particle dispersion and the total volume of the metal salt aqueous solution.

  The concentration of the metal salt as a flocculant in the present invention may be not less than the critical aggregation concentration, but is preferably 1.2 times or more, more preferably 1.5 times or more the critical aggregation concentration.

(Release agent)
The toner of the present invention is preferably a toner obtained by fusing resin particles encapsulating a release agent in an aqueous medium. Thus, the resin particles in which the release agent is encapsulated in the resin particles are salted out / fused in the aqueous medium with the colorant particles, whereby a toner in which the release agent is finely dispersed can be obtained.

  In the toner of the present invention, low molecular weight polypropylene (number average molecular weight = 1500 to 9000), low molecular weight polyethylene, and the like are preferable as the release agent, and ester compounds represented by the following formula are particularly preferable.

R ^1- (OCO-R ² ) _n
In the formula, n is an integer of 1 to 4, preferably 2 to 4, more preferably 3 to 4, particularly preferably 4. R ¹ and R ² each represents a hydrocarbon group that may have a substituent. R ¹ has 1 to 40 carbon atoms, preferably 1 to 20 carbon atoms, and more preferably 2 to 5 carbon atoms. R ² has 1 to 40 carbon atoms, preferably 16 to 30 carbon atoms, and more preferably 18 to 26 carbon atoms.

  Next, the example of a typical compound is shown below.

  The amount of the compound added is 1 to 30% by mass, preferably 2 to 20% by mass, and more preferably 3 to 15% by mass with respect to the total toner.

  The toner of the present invention is preferably prepared by encapsulating the release agent in resin particles by the miniemulsion polymerization method, and salting out and fusing together with the toner particles.

(Charge control agent)
In addition to the colorant and the release agent, a material that can impart various functions as a toner material can be added to the toner. Specific examples include charge control agents. These components can be added simultaneously with the resin particles and the colorant particles in the salting out / fusion step described above, and can be added by various methods such as a method included in the toner and a method of adding to the resin particles themselves.

  As the charge control agent, various known ones that can be dispersed in water can be used. Specific examples include nigrosine dyes, naphthenic acid or higher fatty acid metal salts, alkoxylated amines, quaternary ammonium salt compounds, azo metal complexes, salicylic acid metal salts or metal complexes thereof.

(External additive)
To the toner of the present invention, so-called external additives can be added and used for the purpose of improving fluidity and improving cleaning properties. These external additives are not particularly limited, and various inorganic fine particles, organic fine particles and lubricants can be used.

  Examples of inorganic fine particles that can be used as an external additive include conventionally known fine particles. Specifically, silica fine particles, titanium fine particles, alumina fine particles and the like can be preferably used. These inorganic fine particles are preferably hydrophobic.

  Specific examples of the silica fine particles include commercially available products R-805, R-976, R-974, R-972, R-812, R-809 manufactured by Nippon Aerosil Co., Ltd., and HVK-2150 manufactured by Hoechst Co., Ltd. , H-200, commercially available products TS-720, TS-530, TS-610, H-5, MS-5 manufactured by Cabot Corporation.

  Specific examples of the titanium fine particles include, for example, commercial products T-805 and T-604 manufactured by Nippon Aerosil Co., Ltd., and commercial products MT-100S, MT-100B, MT-500BS, and MT-600 manufactured by Teika Co., Ltd. , MT-600SS, JA-1, commercial products manufactured by Fuji Titanium Co., Ltd. TA-300SI, TA-500, TAF-130, TAF-510, TAF-510T, commercial products IT-S manufactured by Idemitsu Kosan Co., Ltd. IT-OA, IT-OB, IT-OC and the like.

  Specific examples of the alumina fine particles include commercial products RFY-C and C-604 manufactured by Nippon Aerosil Co., Ltd., and commercial products TTO-55 manufactured by Ishihara Sangyo Co., Ltd.

  Examples of the organic fine particles that can be used as the external additive include spherical fine particles having a number average primary particle diameter of about 10 to 2000 nm. Examples of the constituent material of the organic fine particles include polystyrene, polymethyl methacrylate, styrene-methyl methacrylate copolymer, and the like.

  Examples of the lubricant that can be used as an external additive include metal salts of higher fatty acids. Specific examples of such higher fatty acid metal salts include zinc stearate, aluminum stearate, copper stearate, magnesium stearate, calcium stearate, and other stearic acid metal salts; zinc oleate, manganese oleate, iron oleate, olein Oleic acid metal salts such as acid copper and magnesium oleate; palmitate metal salts such as zinc palmitate, copper palmitate, magnesium palmitate and calcium palmitate; linoleic acid metal salts such as zinc linoleate and calcium linoleate; ricinol Examples include ricinoleic acid metal salts such as zinc acid and calcium ricinoleate.

  The addition amount of the external additive is preferably about 0.1 to 5% by mass with respect to the toner.

<External additive addition process>
This step is a step of adding an external additive to the dried toner particles.

  Examples of the apparatus used for adding the external additive include various known mixing apparatuses such as a Turbuler mixer, a Henschel mixer, a Nauter mixer, and a V-type mixer.

(Toner particles)
The particle size of the toner of the present invention is preferably 3 to 10 μm, more preferably 3 to 8 μm in terms of number average particle size. In the toner production method, the particle size can be controlled by the concentration of the flocculant (salting-out agent), the amount of organic solvent added, the fusing time, and the polymer composition.

  When the number average particle diameter is 3 to 10 μm, toner particles having high adhesion force that fly and adhere to the heating member and generate offset in the fixing process are reduced, and transfer efficiency is increased and halftone The image quality is improved, and the image quality of fine lines and dots is improved.

  The number average particle diameter of the toner can be measured using a Coulter Counter TA-II, Coulter Multisizer, SLAD 1100 (Laser Diffraction Particle Size Measuring Device manufactured by Shimadzu Corporation) or the like.

  In the present invention, a Coulter Multisizer is used, and an interface (manufactured by Nikka Machine Co., Ltd.) for outputting the particle size distribution and a personal computer are connected. The aperture in the Coulter Multisizer was 100 μm, and the volume distribution of toner of 2 μm or more (for example, 2 to 40 μm) was measured to calculate the particle size distribution and average particle size.

<Preferable shape factor range of toner particles>
As for the shape factor of the toner of the present invention, 1.0 to 1.6 is 65 number% or more, preferably 1.2 to 1.6 is 65 number% or more, particularly preferably 1.2 to 1. 6 is 70% by number or more.

  The shape factor of the toner of the present invention is represented by the following formula and indicates the degree of roundness of the toner particles.

Shape factor = ((maximum diameter / 2) ² × π) / projection area Here, the maximum diameter is the distance between the parallel lines when the projected image of toner particles on a plane is sandwiched between two parallel lines. The maximum particle width. The projected area refers to the area of the projected image of the toner particles on the plane. In the present invention, this shape factor is obtained by taking a photograph in which the toner particles are magnified 2000 times with a scanning electron microscope, and then using “SCANNING IMAGE ANALYZER” (manufactured by JEOL Ltd.) based on this photograph. It was measured by performing analysis. At this time, the shape factor of the present invention was measured by the above formula using 100 toner particles.

  As the toner of the present invention, when the particle size of the toner particle is D (μm), the natural logarithm lnD is taken on the horizontal axis, and the number-based particle size distribution is divided into a plurality of classes at intervals of 0.23. In the histogram shown, the sum (M) of the relative frequency (m1) of the toner particles included in the most frequent class and the relative frequency (m2) of the toner particles included in the next most frequent class after the most frequent class is 70. % Of the toner is preferable.

  When the sum (M) of the relative frequency (m1) and the relative frequency (m2) is 70% or more, the dispersion of the particle size distribution of the toner particles becomes narrow. Therefore, selective development can be performed by using the toner in the image forming process. Can be reliably suppressed.

  In the present invention, the histogram showing the particle size distribution based on the number is a natural logarithm lnD (D: particle size of individual toner particles) having a plurality of classes (0 to 0.23: 0.23) at intervals of 0.23. 0.46: 0.46-0.69: 0.69-0.92: 0.92-1.15: 1.15-1.38: 1.38-1.61: 1.61-1. 84: 1.84 to 2.07: 2.07 to 2.30: 2.30 to 2.53: 2.53 to 2.76, and so on). This histogram was created by transferring the particle size data of the sample measured by the Coulter Multisizer to the computer via the I / O unit according to the following conditions and using the particle size distribution analysis program in the computer. is there.

〔Measurement condition〕
1: Aperture: 100 μm
2: Sample preparation method: electrolytic solution [ISOTON R-11 (manufactured by Coulter Scientific Japan)] 50-100 ml, an appropriate amount of a surfactant (neutral detergent) was added and stirred, and 10-20 mg of a measurement sample was added thereto. Add. This system is prepared by dispersing for 1 minute with an ultrasonic disperser.

  The toner of the present invention preferably has a volume-based median diameter (D50v) of 3 to 8 μm. By setting the volume-based median diameter in the above range, for example, it is possible to faithfully reproduce a very minute image of 1200 dpi (dpi; number of dots per inch (2.54 cm)) level.

  The toner of the present invention has one of the problems to be able to faithfully reproduce the color of a photographic image. By making the volume-based median diameter a small diameter level in the above range, a photographic image is formed. The dot image is miniaturized and a high-definition photographic image equivalent to or higher than the printed image is obtained. In particular, in a printing field called “on-demand printing” where a print order is received at a level of several hundred to several thousand copies, high-quality prints containing high-definition photographic images can be quickly delivered to the user.

  The volume-based median diameter (D50v diameter) of toner can be measured and calculated using a device in which a computer system for data processing is connected to Coulter Multisizer 3 (manufactured by Beckman Coulter, Inc.).

  As a measurement procedure, 0.02 g of toner is blended with 20 ml of a surfactant solution (for example, a surfactant solution obtained by diluting a neutral detergent containing a surfactant component 10 times with pure water for the purpose of dispersing the toner). After that, ultrasonic dispersion is performed for 1 minute to prepare a toner dispersion. This toner dispersion is injected into a beaker containing ISOTON II (manufactured by Beckman Coulter, Inc.) in a sample stand with a pipette until a measurement concentration of 5 to 10% is reached, and the measuring machine count is set to 2500. To do. The Coulter Multisizer 3 having an aperture diameter of 50 μm is used.

  The toner of the present invention preferably has a coefficient of variation (CV value) in the volume-based particle size distribution of 2 to 21%, more preferably 5 to 15%.

  The coefficient of variation (CV value) in the volume-based particle size distribution represents the degree of dispersion in the particle size distribution of the toner particles on the volume basis, and is defined by the following equation.

CV value (%) = (standard deviation in number particle size distribution) / (median diameter (D50v) in number particle size distribution) × 100
The smaller the CV value, the sharper the particle size distribution, and the larger the toner particle size. In other words, since toners of uniform sizes can be obtained, it is possible to reproduce fine images and fine lines required for digital image formation with higher accuracy. Further, when printing a photographic image, it is possible to create a high-quality photographic image of an image level made with printing ink or higher by using small-diameter toner having a uniform size.

  The toner of the present invention preferably has a softening point temperature (Tsp) of 70 to 110 ° C, more preferably 70 to 100 ° C. The colorant used in the toner of the present invention has a stable property that the spectrum does not change even under the influence of heat, but is added to the toner during fixing by setting the softening point in the above range. The influence of heat can be further reduced. Therefore, since image formation can be performed without imposing a burden on the colorant, it is expected that a wider and more stable color reproducibility is expressed.

  Further, by setting the softening point of the toner within the above range, the toner image can be fixed at a temperature lower than that of the prior art, and the environment-friendly image formation in which the power consumption is reduced can be realized.

The softening point of the toner can be controlled by, for example, the following methods alone or in combination. That is,
(1) The type and composition ratio of monomers used for resin formation are adjusted.
(2) The molecular weight of the resin is adjusted according to the type and amount of chain transfer agent.
(3) Adjust the type and amount of wax.

Further, the method for measuring the softening point temperature of the toner is specifically “Flow Tester CFT-500 (manufactured by Shimadzu Corporation)”, molded into a columnar shape with a height of 10 mm, and at a heating rate of 6 ° C./min. While being heated, a pressure of 1.96 × 10 ⁶ Pa is applied from the plunger, and the pressure is pushed out from a nozzle having a diameter of 1 mm and a length of 1 mm. Thereby, a curve between the plunger drop amount and temperature of the flow tester (softening flow curve) ), And the temperature at the first outflow is the melting start temperature, and the temperature for the drop of 5 mm is the softening point temperature.

  Next, a method for producing the toner of the present invention will be described.

  The toner of the present invention comprises at least a resin and particles (hereinafter also referred to as colored particles) containing a colorant represented by the general formulas (1) and (2). The method for producing the colored particles constituting the toner of the present invention is not particularly limited and can be produced by a conventional toner production method. That is, a toner manufacturing method by a so-called pulverization method in which a toner is prepared through a kneading, pulverization, and classification process, or a so-called polymerized toner in which a polymerizable monomer is polymerized and particles are formed while simultaneously controlling the shape and size. It can be produced by applying a production method (for example, an emulsion polymerization method, a suspension polymerization method, a polyester elongation method, etc.).

  When the toner of the present invention is produced by a pulverization method, it is preferable to produce the toner while maintaining the temperature of the kneaded product at 130 ° C. or lower. This is because when the temperature applied to the kneaded product exceeds 130 ° C., the colorant in the kneaded product may change in the agglomerated state due to the action of heat applied to the kneaded product, and the uniform aggregated state may not be maintained. Because. If variations occur in the aggregated state, the color tone of the produced toner varies, which may cause color turbidity.

(Developer)
The toner of the present invention may be used as a one-component developer or a two-component developer.

  When used as a one-component developer, a non-magnetic one-component developer or a magnetic one-component developer containing about 0.1 to 0.5 μm of magnetic particles in the toner can be used. be able to.

  Further, it can be mixed with a carrier and used as a two-component developer. In this case, conventionally known materials such as metals such as iron, ferrite and magnetite, and alloys of these metals with metals such as aluminum and lead can be used as the magnetic particles of the carrier. Ferrite particles are particularly preferable. The magnetic particles preferably have a volume average particle size of 15 to 100 μm, more preferably 25 to 80 μm.

  The volume average particle diameter of the carrier can be typically measured by a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by SYMPATEC) equipped with a wet disperser.

  The carrier is preferably a carrier in which magnetic particles are further coated with a resin, or a so-called resin dispersion type carrier in which magnetic particles are dispersed in a resin. The resin composition for coating is not particularly limited, and for example, olefin resin, styrene resin, styrene-acrylic resin, silicone resin, ester resin, fluorine-containing polymer resin, or the like is used. In addition, the resin for constituting the resin-dispersed carrier is not particularly limited, and a known resin can be used. For example, a styrene-acrylic resin, a polyester resin, a fluorine resin, a phenol resin, or the like is used. be able to.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

Example [Production of Cyan Toner]
(Preparation of cyan toner 1)
The following toner composition was put into a Henschel mixer (manufactured by Mitsui Miike Mining Co., Ltd.), and the peripheral speed of the stirring blade was set to 25 m / second and mixed for 5 minutes.

Polyester resin (bisphenol A-ethylene oxide adduct, terephthalic acid, trimellitic acid condensate, weight average molecular weight 20,000) 100 parts by weight Compound (1-1) 2 parts by weight Compound (2-1) 2 parts by weight Silanol Compound 1 0.05 parts by weight Release agent (pentaerythritol tetrastearate) 6 parts by weight Charge control agent (boron dibenzylate) 1 part by weight

  The mixture is kneaded with a twin-screw extrusion kneader, then coarsely pulverized with a hammer mill, then pulverized with a turbo mill pulverizer (manufactured by Turbo Kogyo Co., Ltd.), and further finely classified with an airflow classifier utilizing the Coanda effect. By carrying out, colored particles 1 having a volume-based median diameter of 5.5 μm were obtained.

  Next, the following external additives were added to the colored particles 1 and subjected to external addition treatment with a Henschel mixer (manufactured by Mitsui Miike Mining Co., Ltd.) to produce the cyan toner 1 of the present invention.

(External additive)
Silica treated with hexamethylsilazane (average primary particle size: 12 nm) 0.6 parts by mass Titanium dioxide treated with n-octylsilane (average primary particle size: 24 nm) 0.8 parts by mass Was performed under conditions of a peripheral speed of 35 m / sec, a processing temperature of 35 ° C., and a processing time of 15 minutes.

(Preparation of cyan toners 2 to 4)
Cyan toners 2 to 4 of the present invention were prepared in the same manner except that the compound and amount of the colorant compound were changed as shown in Table 1 in the production of cyan toner 1.

(Preparation of cyan toner 5)
(1) Preparation of Colorant Fine Particle Dispersion 1 11.5 parts by mass of sodium n-dodecyl sulfate was added to 160 parts by mass of ion-exchanged water, and dissolved and stirred to prepare an aqueous surfactant solution. To this surfactant aqueous solution, 2 parts by mass of compound (1-1) and 2 parts by mass of compound (2-1) are added, and 0.05 part by mass of silanol compound 1 is gradually added. Dispersion treatment was performed using Motion CLM-0.8 (manufactured by M Technique Co., Ltd.) to prepare Colorant Fine Particle Dispersion Liquid 1.

  The colorant fine particles 1 in the colorant fine particle dispersion 1 had a volume-based median diameter of 98 nm. The volume-based median diameter was measured using MICROTRAC UPA-150 (manufactured by HONEYWELL) under the following measurement conditions.

Sample refractive index 1.59
Sample specific gravity 1.05 (in terms of spherical particles)
Solvent refractive index 1.33
Solvent viscosity 0.797 (30 ° C), 1.002 (20 ° C)
0-point adjustment Ion-exchanged water was added to the measurement cell for preparation.

(2) Preparation of core part resin particles 1 Core part resin particles 1 having a multilayer structure were prepared through the following first-stage polymerization, second-stage polymerization, and third-stage polymerization.

(A) First-stage polymerization 4 parts by mass of an anionic surfactant shown below (Structural Formula 1) together with 3040 parts by mass of ion-exchanged water are charged into a reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introduction device. Then, a surfactant aqueous solution was prepared.

(Structural Formula 1) C ₁₀ H ₂₁ (OCH ₂ CH ₂ ) ₂ SO ₃ Na
A polymerization initiator solution in which 10 parts by mass of potassium persulfate (KPS) was dissolved in 400 parts by mass of ion-exchanged water was added to the surfactant aqueous solution, and the temperature was raised to 75 ° C. The resulting monomer mixture was dropped into the reaction vessel over 1 hour.

Styrene 532 parts by mass n-butyl acrylate 200 parts by mass Methacrylic acid 68 parts by mass n-octyl mercaptan 16.4 parts by mass After the above monomer mixture is added dropwise, the system is heated and stirred at 75 ° C. for 2 hours. Polymerization (first stage polymerization) was performed to prepare resin particles. Let this resin particle be resin particle A1. The weight average molecular weight of the resin particles A1 produced by the first stage polymerization was 16,500.

(B) Second stage polymerization Into a flask equipped with a stirrer, a monomer mixed solution composed of the following compounds was charged, and then paraffin wax HNP-57 (manufactured by Nippon Wax Co., Ltd.) 93.8 as a release agent. A part by mass was added and heated to 90 ° C. to dissolve. In this way, a monomer solution was prepared.

Styrene 101.1 parts by weight n-butyl acrylate 62.2 parts by weight Methacrylic acid 12.3 parts by weight n-octyl mercaptan 1.75 parts by weight On the other hand, 3 parts by weight of the anionic surfactant is dissolved in 1560 parts by weight of ion-exchanged water. An aqueous surfactant solution was prepared and heated to 98 ° C. A mechanical disperser having a circulation path after adding 32.8 parts by mass (in terms of solid content) of the resin particles A1 to the surfactant aqueous solution and further adding a monomer solution containing the paraffin wax. The mixture was mixed and dispersed for 8 hours using CLEAMIX (M Technique Co., Ltd.). An emulsified particle dispersion containing emulsified particles having a dispersed particle size of 340 nm was prepared by the mixing and dispersing.

  Next, a polymerization initiator solution in which 6 parts by mass of potassium persulfate is dissolved in 200 parts by mass of ion-exchanged water is added to the emulsified particle dispersion, and the system is polymerized by heating and stirring at 98 ° C. for 12 hours. (Second stage polymerization) was performed to prepare resin particles. Let this resin particle be resin particle A2. The weight average molecular weight of the resin particles A2 prepared by the second stage polymerization was 23,000.

(C) Third-stage polymerization A polymerization initiator solution prepared by dissolving 5.45 parts by mass of potassium persulfate in 220 parts by mass of ion-exchanged water is added to the resin particles A2 obtained by the second-stage polymerization, and the temperature is 80 ° C. Under the temperature conditions, a monomer mixture composed of the following compounds was added dropwise over 1 hour.

Styrene 293.8 parts by mass n-butyl acrylate 154.1 parts by mass n-octyl mercaptan 7.08 parts by mass After completion of the dropwise addition, the mixture was heated and stirred for 2 hours to perform polymerization (third stage polymerization). The core part resin particle 1 was produced by cooling to 28 ° C. Prepared by third stage polymerization. The weight average molecular weight of the core portion resin particles 1 was 26,800.

(3) Preparation of resin particles for shell The polymerization reaction and after the reaction were the same except that the monomer mixture used in the first stage polymerization in the preparation of the resin particles 1 for the core was changed to the following: The resin particle 1 for shells was produced by performing the above process.

Styrene 624 parts by mass 2-ethylhexyl acrylate 120 parts by mass Methacrylic acid 56 parts by mass n-octyl mercaptan 16.4 parts by mass (4) Preparation of toner 5 Cyan toner 5 of the present invention was prepared by the following procedure.

(A) Formation of core part In a reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introducing device,
Resin particle for core part 420.7 parts by mass (solid content conversion)
900 parts by mass of ion-exchanged water 200 parts by mass of the colorant particle dispersion 1 were added and stirred. After adjusting the temperature in the reaction vessel to 30 ° C., a 5 mol / liter aqueous sodium hydroxide solution was added to adjust the pH to 8-11.

  Next, an aqueous solution obtained by dissolving 2 parts by mass of magnesium chloride hexahydrate in 1000 parts by mass of ion-exchanged water was added at 30 ° C. over 10 minutes with stirring. After standing for 3 minutes, the heating was started, and the system was heated to 65 ° C. over 60 minutes to associate the particles. In this state, the particle size of the associated particles was measured using Multisizer 3 (manufactured by Coulter, Inc.), and when the volume-based median diameter of the associated particles reached 5.5 μm, 40.2 parts by mass of sodium chloride was added to the ion-exchanged water 1000 The association was stopped by adding an aqueous solution dissolved in parts by mass.

  After the association was stopped, the core portion 1 was produced by continuing the fusion by heating and stirring for 1 hour at a liquid temperature of 70 ° C. as an aging treatment.

  It was 0.912 when the average circularity of the core part 1 was measured by FPIA2000 (made by Systex).

(B) Formation of shell Next, 96 parts by mass of resin particles 1 for shell was added at 65 ° C., and 2 parts by mass of magnesium chloride hexahydrate was dissolved in 1000 parts by mass of ion-exchanged water. After adding the aqueous solution over 10 minutes, the temperature was raised to 70 ° C. and stirring was performed for 1 hour. In this way, after the shell resin particles 1 were fused to the surface of the core portion 1, an aging treatment was performed at 75 ° C. for 20 minutes to form a shell.

  Thereafter, an aqueous solution in which 40.2 parts by mass of sodium chloride was dissolved in 1000 parts by mass of ion-exchanged water was added to stop shell formation. Further, the colored particles produced by cooling to 30 ° C. at a rate of 8 ° C./min are filtered, washed repeatedly with ion exchange water at 45 ° C., and then dried with hot air at 40 ° C. Colored particles 2 having a shell were produced.

(C) External Addition Treatment The following external additive was added to the produced colored particles 2 and external addition treatment was performed with a Henschel mixer (manufactured by Mitsui Miike Mining Co., Ltd.) to produce cyan toner 5.

Silica treated with hexamethylsilazane (average primary particle size: 12 nm) 0.6 parts by mass Titanium dioxide treated with n-octylsilane (average primary particle size: 24 nm) 0.8 parts by mass Was performed under conditions of a peripheral speed of 35 m / sec, a processing temperature of 35 ° C., and a processing time of 15 minutes.

(Preparation of cyan toners 6 to 16)
Cyan toners 6 to 16 of the present invention were produced in the same manner except that the types and amounts of the compounds were changed as shown in Table 1 in the production of cyan toner 5.

(Preparation of cyan toners 17 to 21)
Cyan toners 17 to 21 of comparative examples were prepared in the same manner except that the types and amounts of the compounds were changed as shown in Table 1 in the production of cyan toner 5. However, for cyan toners 20 and 21, compounds previously pigmented according to the following were used.

Pigmentation of crude copper phthalocyanine (CI Pigment Blue 15.3) 500 parts of crude copper phthalocyanine having no substituent on the phthalocyanine ring was placed in an attritor loaded with steel beads and mechanically treated at 90 ° C. for 1 hour. Grinding was performed to obtain crude copper phthalocyanine ground by mechanical means. 400 parts of crude copper phthalocyanine and 400 parts of diethylene glycol, which were ground by the obtained mechanical means, were charged into a double-arm kneader and kneaded at 95 ° C. for 50 minutes for pigmentation. Thereafter, the kneaded product was taken out into water, sufficiently stirred, filtered and washed with water, and then the cake after filtration was dried to obtain a copper phthalocyanine pigment.

[Production of yellow, magenta, and black toner]
(Production of yellow toner)
In the production of cyan toner 5, the colorant was changed to C.I. I. A yellow toner was prepared in the same manner except that the pigment yellow 74 was used.

(Production of magenta toner)
In the production of cyan toner 5, the colorant was changed to C.I. I. A magenta toner was produced in the same manner except that the pigment red 122 was used.

(Production of black toner)
A black toner was prepared in the same manner as in the preparation of the cyan toner 5 except that the colorant was changed to carbon black “Mogal L” (manufactured by Cabot Corporation).

(Preparation of developer)
Each of the cyan toners 1 to 21 and the yellow, magenta, and black toners is mixed with a ferrite carrier having a volume average particle diameter of 60 μm coated with a silicone resin, and the cyan developer 1 to 21 having a toner concentration of 6% and the yellow developer. Agent, magenta developer, and black developer were prepared.

[Evaluation of cyan toner]
The evaluation was performed by loading a developing device in which each developer was charged into a commercially available composite printer, bizhub Pro C500 (manufactured by Konica Minolta Business Technologies, Inc.).

  Further, a belt fixing type fixing device was mounted on the printer for evaluation. Various conditions such as the surface material and surface temperature of the heating roller in the belt fixing type fixing device described above were as follows.

Fixing speed: 230mm / sec
Heat roller surface material: Polytetrafluoroethylene (PTFE)
Heating roller surface temperature: 125 ° C
<Image evaluation>
In the evaluation, the toner prepared above was loaded in the evaluation device in order, and the following items were evaluated in an environment of normal temperature and normal humidity (20 ° C., 55% RH).

Using the above-described image forming apparatus, a reflection image (an image on the paper) was prepared on the paper using the toner set containing the cyan toner of the present invention, and evaluated by the following method. The toner adhesion amount was evaluated in the range of 0.7 ± 0.05 (mg / cm ² ).

(saturation)
Using the produced cyan toner, a solid image having a hue angle of 240 degrees and a maximum saturation of lightness 40 and 70 was output in the CIELAB color space. The cyan toner 17 of the comparative example was used as a reference and evaluated according to the following criteria.

A: Saturation improvement is 20% or more B: Saturation improvement is 15% or more and less than 20% C: Saturation improvement is 10% or more and less than 15% D: Saturation improvement is less than 10% A and B are It is a level that can withstand practical use.

(Color reproducibility)
Using each of the solid image portions of yellow / magenta / cyan and R / G / B, the color gamut was measured to confirm the area expansion. The area is compared with the color gamut of the Japan color for printing as 100. An enlargement of 10% or more was designated as A, an enlargement of 10% to 10% was designated as B, a less than 5% was designated as C, and an unexpanded was designated as D. A and B are at a level that can sufficiently withstand practical use.

<Image preservation>
(Light resistance)
The image used for the saturation evaluation was irradiated with a xenon fade meter for 7 days, and the hue change of the mixed color image before and after the irradiation was evaluated. The pre-irradiation image was taken as 100%, the dye residual ratio was taken as A, 90% or more, B from 80% to less than 90%, C from 70% to less than 80%, and D, less than 70%. A and B are at a level that can sufficiently withstand practical use.

(Ozone resistance)
Under the condition that the ozone gas concentration was set to 5 ppm (25 ° C .; 60% RH), the mixed color image was exposed to ozone gas for 7 days. Hue changes were evaluated for the mixed color images before and after exposure. The image before exposure was defined as 100%, and the dye residual ratio was defined as A when the ratio was 90% or more, B as 80% or more but less than 90%, C as 70% or more but less than 80%, and D as less than 70%. A and B are at a level that can sufficiently withstand practical use.

<Workability>
The workability from the colorant compound synthesis process to the toner preparation process including the pigmentation process was evaluated. Workability was evaluated on a 10-point scale based on the time and number of processes required for 5 workers. The average score of 5 people was 10 to 9 points, the average score of 10 people was B to 9 to 8 points, and the average score of 10 people was C to be 8 points or less. A and B are at a level that can sufficiently withstand practical use.

  The evaluation results are shown in Table 1.

  From Table 1, the cyan toner of the present invention has durability such as light resistance and ozone resistance without passing through the pigmentation step, has excellent coloring power, and has good color reproducibility of low brightness and high brightness. I understand that there is.

Claims (3)

An electrophotographic cyan toner comprising a compound represented by the following general formula (1) and a compound represented by the following general formula (2).

(In the formula, M ₁ represents Si or Ge. Z ₁ and Z ₂ represent an alkyl group, an aryl group, a hydroxy group, a halogen atom, an aryloxy group, an alkoxy group, an acyloxy group, or —OSiRaRbRc (where Ra, Rb and Rc each independently, an alkyl group, an aryl group, an alkoxy group, .Z 1 represent any of the groups represented by an aryl _group), Z ₂ is selected from the same or different from each other .R ₁ to R ₈ represents a hydrogen atom, an alkyl group, an aryl group, an alkylsulfonyl group, an alkylsulfamoyl group or —SiRaRbRc (where Ra, Rb and Rc each independently represents an alkyl group, an aryl group, an alkoxy group or an aryloxy group) And R _{1 to} R ₈ may be the same as or different from each other.

(In the formula, M ₂ represents Mg, Ca, Mn, Fe, Co, Ni, Cu or Zn. R _{9 to} R ₁₆ represent a hydrogen atom, an alkyl group, an aryl group, an alkylsulfonyl group, an alkylsulfamoyl group, or -SiRaRbRc (wherein Ra, Rb, and Rc each independently represents an alkyl group, an aryl group, an alkoxy group, or an aryloxy group) R _{9 to} R ₁₆ may be the same as each other. May be different, but not all are hydrogen atoms at the same time.) 2. The cyan toner for electrophotography according to claim 1, wherein in the general formula (2), R _{9 to} R ₁₆ are a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. 3. The electrophotographic cyan toner according to claim 1, wherein in the general formula (2), M ₂ is any one of Zn, Cu, and Mg.