JP5994454B2 - Cyan toner for electrostatic image development - Google Patents

Description

  The present invention relates to an electrostatic image developing cyan toner used for electrophotographic image formation.

In the print-on-demand field for printing applications, which has been spreading in recent years due to the convenience and speed of data processing, in order to provide printed matter with higher customer satisfaction, there is a demand for an increase in the color gamut of toner used. It is growing.
In general, it is known that the expansion of the color gamut of a toner can be achieved by increasing the content of the colorant in the toner particles or increasing the dispersibility in the toner particles to obtain high saturation. (For example, see Patent Document 1 and Patent Document 2).

  However, when the content of the colorant in the toner particles is increased, the exposed portion of the colorant on the surface of the toner particles inevitably increases, and as a result, the chargeability of the toner becomes unstable, resulting in high stability. It has been found that an image cannot be formed.

  On the other hand, as a specific method for increasing the dispersibility of the colorant in the toner particles, for example, when an emulsion aggregation method is used as a toner production method, a general method for preparing a dispersion of colorant fine particles is used. There are methods of increasing the dispersion time and increasing the share (shearing force) related to dispersion by using a media dispersion method.

  However, if the fine particles of the colorant finely dispersed in the aqueous medium by increasing the dispersion time or increasing the share for dispersion as described above are aggregated with the binder resin fine particles serving as the binder resin, Due to the small dispersion diameter of the fine particles of the colorant, re-aggregation of the fine particles of the colorant is likely to occur, and eventually the dispersibility of the colorant in the finally obtained toner particles cannot be increased.

JP 2009-265227 A JP 2009-093161 A

  The present invention has been made in consideration of the above-described circumstances, and an object of the present invention is to provide cyan for electrostatic charge image development, which can obtain excellent chargeability and can develop a highly saturated cyan color. To provide toner.

The cyan toner for developing an electrostatic image of the present invention comprises cyan toner particles containing a binder resin and a cyan colorant,
The cyan colorant contains a silicon phthalocyanine compound represented by the following general formula (1).

[In the above formula, two Z are each, indicates any of the groups represented by the following formula (a) ~ formula (j), at least one Z is Formula (b), Formula (f) or It is group represented by Formula (i) . ]

  In the cyan toner for developing electrostatic images of the present invention, it is preferable that the cyan colorant contains a phthalocyanine compound other than the silicon phthalocyanine compound.

  According to the cyan toner for developing an electrostatic charge image of the present invention, by containing the silicon phthalocyanine compound represented by the general formula (1) as a cyan colorant, the silicon phthalocyanine compound has high dispersibility in the cyan toner particles. The color gamut can be expanded by being dispersed by the above, and the color gamut can be expanded, and an excellent charging property can be obtained and an image can be formed with high stability.

Hereinafter, the present invention will be specifically described.
The cyan toner for developing an electrostatic image of the present invention (hereinafter also simply referred to as “cyan toner”) includes at least a binder resin and a silicon phthalocyanine compound represented by the general formula (1) (hereinafter referred to as “specific silicon phthalocyanine”). A cyan toner particle containing a cyan colorant having a compound (also referred to as a “compound”).

[Cyan colorant]
The cyan colorant constituting the cyan toner of the present invention contains a specific silicon phthalocyanine compound.
The cyan colorant may be composed of one or more specific silicon phthalocyanine compounds, and for cyan toning, a phthalocyanine compound other than the specific silicon phthalocyanine compound (hereinafter, “ Other phthalocyanine compounds ") may also be contained, and known cyan pigments and cyan dyes other than phthalocyanine compounds may also be contained.
As a compound to be contained together with a specific silicon phthalocyanine compound, it is preferable to use other phthalocyanine compounds. This is because a specific silicon phthalocyanine compound and a phthalocyanine skeleton are common, so that the dispersibility of other phthalocyanine compounds can also be improved, and as a result, the dispersibility of the entire cyan colorant in cyan toner particles is increased. Because it can.

In the above general formula (1) representing a specific silicon phthalocyanine compound, two Z's each represent any of the groups represented by the above formula (a) to the above formula (j), and at least one Z is a formula It is preferably a group represented by (b), formula (f) or formula (i), particularly preferably at least one Z is a group represented by formula (b). .
The two Z are preferably the same as each other, but may be different.

  Examples of other phthalocyanine compounds that can be contained together with a specific silicon phthalocyanine compound include copper phthalocyanine and zinc phthalocyanine.

In the cyan colorant constituting the cyan toner of the present invention, the ratio X: Y of the content X of the specific silicon phthalocyanine compound and the content Y of the other phthalocyanine compound may be 100: 0 to 20:80. More preferably, it is 80: 20-20: 80, More preferably, it is 70: 30-30: 70.
When the ratio X: Y of the mass X of the specific silicon phthalocyanine compound and the mass Y of the other phthalocyanine compound is in the above range, the dispersibility of the other phthalocyanine compound by the specific silicon phthalocyanine compound can be improved. The effect that can be obtained can be sufficiently obtained.

  The content of the cyan colorant in the cyan toner particles constituting the cyan toner of the present invention is preferably 2 to 20% by mass and more preferably 3 to 15% by mass with respect to the cyan toner particles. When the content of the cyan colorant in the cyan toner particles is in the above range, a sufficient density can be obtained for an image formed with the cyan toner, and excellent chargeability can be ensured.

[Synthesis Method of Specific Silicon Phthalocyanine Compound]
The specific silicon phthalocyanine compound can be synthesized by a conventionally known synthesis method. Specifically, the method disclosed in JP2009-265227A can be used.

[Binder resin]
The binder resin constituting the cyan toner of the present invention is not particularly limited.
Specific examples of such binder resins include, for example, vinyl polymers such as styrene resins, acrylic resins, styrene-acrylic copolymer resins, olefin resins, polyester resins, silicone resins, amide resins, and epoxy resins. In particular, in order to improve transparency and color reproducibility of a superimposed image, a styrene-acrylic copolymer resin having a high transparency, a low melting property, and a high sharp melt property is preferable. It is mentioned in. These can be used alone or in combination of two or more.

The cyan toner of the present invention has a shell layer in which the cyan toner particles constituting the toner toner are composed of core particles containing a binder resin and a cyan colorant, and a resin containing substantially no cyan colorant covering the outer peripheral surface thereof. In this case, the resin constituting the shell layer is made of a resin different from the binder resin constituting the core particles. By constituting the cyan toner particles as having a core-shell structure, high production stability and storage stability can be obtained for the cyan toner particles.
The cyan toner particles having the core-shell structure are not limited to a form in which the shell layer completely covers the core particles, but may be those in which a part of the core particles is covered. Further, a part of the resin constituting the shell layer may form a domain or the like in the core particle. Furthermore, the shell layer may have a multilayer structure of two or more layers made of resins having different compositions.

The binder resin constituting the cyan toner of the present invention preferably has a weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) of THF soluble content of 10,000 to 50,000. Preferably it is 25,000-35,000.
When the weight average molecular weight (Mw) of the binder resin is in the above range, low-temperature fixability and fixability can be reliably obtained. On the other hand, when the weight average molecular weight (Mw) of the binder resin is excessive, the low-temperature fixability may not be sufficiently obtained. Further, when the weight average molecular weight (Mw) of the binder resin is too small, there is a possibility that the fixing separation property cannot be obtained sufficiently.

The molecular weight measurement by GPC was performed as follows. That is, using an apparatus “HLC-8220” (manufactured by Tosoh Corporation) and a column “TSKguardcolumn + TSKgelSuperHZM-M3 series” (manufactured by Tosoh Corporation), while maintaining the column temperature at 40 ° C., tetrahydrofuran (THF) was used as a carrier solvent at a flow rate of 0. Flow at 2 ml / min, and dissolve the measurement sample in tetrahydrofuran to a concentration of 1 mg / ml under a dissolution condition where treatment is performed for 5 minutes using an ultrasonic disperser at room temperature, and then treat with a membrane filter having a pore size of 0.2 μm. A sample solution is obtained, and 10 μL of this sample solution is injected into the apparatus together with the above carrier solvent, detected using a refractive index detector (RI detector), and the molecular weight distribution of the measurement sample is determined as a monodisperse polystyrene standard. Calculation is performed using a calibration curve measured using particles. As a standard polystyrene sample for calibration curve measurement, molecular weights manufactured by Pressure Chemical Co., Ltd. are 6 × 10 ² , 2.1 × 10 ³ , 4 × 10 ³ , 1.75 × 10 ⁴ , 5.1 × 10 ⁴ , 1 .1 × 10 ⁵ , 3.9 × 10 ⁵ , 8.6 × 10 ⁵ , 2 × 10 ⁶ , 4.48 × 10 ⁶ , and at least about 10 standard polystyrene samples were measured, and a calibration curve It was created. A refractive index detector was used as the detector.

[Softening point of cyan toner]
The softening point of the cyan toner of the present invention is preferably 80 to 120 ° C., more preferably 90 to 110 ° C., from the viewpoint of obtaining low temperature fixability for the cyan toner.

The softening point of cyan toner is measured by a flow tester shown below.
Specifically, first, in an environment of 20 ° C. and 50% RH, 1.1 g of cyan toner was placed in a petri dish, leveled, allowed to stand for 12 hours or more, and then a molding machine “SSP-10A” (Shimadzu Corporation) Ltd.) by 30 seconds pressed with a force of 3820kg / cm ^2, to create a molded sample of the cylindrical diameter 1 cm, then the molded sample, 24 ° C., in an environment of 50% RH, flow tester "CFT- 500D "(manufactured by Shimadzu Corporation), with a load of 196 N (20 kgf), a starting temperature of 60 ° C., a preheating time of 300 seconds, and a heating rate of 6 ° C./minute, from the hole of the cylindrical die (1 mm diameter × 1 mm) extruded from the time of preheating ends with piston diameter 1 cm, offset method temperature T _offset measured by setting the offset value 5mm at a melt temperature measurement method of temperature ramps are cyan toner It is the softening point.

[Cyan toner glass transition point]
The cyan toner of the present invention preferably has a glass transition point (Tg) of 10 to 90 ° C, more preferably 20 to 65 ° C.

Here, the glass transition point of cyan toner is measured using “Diamond DSC” (Perkin Elmer).
As a measurement procedure, 3.0 mg of a sample (cyan toner) is sealed in an aluminum pan and set in a holder. The reference used an empty aluminum pan. The measurement conditions were a measurement temperature of 0 ° C. to 200 ° C., a temperature increase rate of 10 ° C./min, a temperature decrease rate of 10 ° C./min, and heat-cool-heat temperature control. Perform analysis based on the data in Heat, draw a baseline extension before the rise of the first endothermic peak, and a tangent line indicating the maximum slope between the rise of the first peak and the peak apex, The intersection point is shown as the glass transition point.

[Cyan toner particle size]
The particle size of the cyan toner of the present invention is preferably 3 to 10 μm, and more preferably 3 to 8 μm, for example, on a volume basis median diameter. When the volume-based median diameter is in the above range, for example, a very minute dot image at a level of 1200 dpi (dpi; number of dots per inch (2.54 cm)) can be faithfully reproduced.

  The volume-based median diameter of cyan toner is measured and calculated using a measuring device in which a computer system for data processing (manufactured by Beckman Coulter) is connected to "Multisizer 3" (manufactured by Beckman Coulter). is there. Specifically, 0.02 g of cyan toner is added to 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 cyan toner). After adding and mixing, ultrasonic dispersion was performed for 1 minute to prepare a cyan toner dispersion, and this cyan toner dispersion was placed in a beaker containing “ISOTON II” (manufactured by Beckman Coulter) in the sample stand. Inject with a pipette until the displayed concentration of the measuring device is 8%. Here, a reproducible measurement value can be obtained by setting the concentration range. In the measuring apparatus, the measurement particle count is 25000, the aperture diameter is 100 μm, the frequency range is calculated by dividing the measurement range of 1 to 30 μm into 256, and the volume integrated fraction is 50 % Particle diameter is defined as the volume-based median diameter.

[Average circularity of cyan toner]
The cyan toner of the present invention has an arithmetic average value of circularity represented by the following formula (T) of 0.850 to 0.990 from the viewpoint of improving transfer efficiency for each cyan toner particle constituting the cyan toner. It is preferable that
Formula (T): Circularity = perimeter of perfect circle having projection area equivalent to particle projection image / perimeter of particle projection image

Here, the average circularity of the cyan toner particles is a value measured using “FPIA-2100” (manufactured by Sysmex).
Specifically, cyan toner particles are moistened in an aqueous surfactant solution, and ultrasonic dispersion is performed for 1 minute. After dispersion, the HPF is used in the measurement condition HPF (high magnification imaging) mode using “FPIA-2100”. Measurement is performed at an appropriate concentration of 3000 to 10,000 detections. Within this range, reproducible measurement values can be obtained.

  The cyan toner of the present invention can be used together with a yellow toner, a magenta toner, and a black toner to form a color image. Such a yellow toner, a magenta toner, and a black toner have a softening point, a glass transition, and the like. It is preferable that the toner is designed so that the point, particle size, and the like are the same as those of the cyan toner.

[Method for producing cyan toner]
Examples of the method for producing the cyan toner of the present invention include kneading / pulverization method, suspension polymerization method, emulsion polymerization method, emulsion polymerization aggregation method, miniemulsion polymerization aggregation method, encapsulation method, and other known methods. Can do. As a method for producing cyan toner, emulsion polymerization is performed from the viewpoint of production cost and production stability, considering that it is necessary to obtain cyan toner having a reduced particle size in order to achieve high image quality. It is preferable to use an agglomeration method.

  In the emulsion polymerization aggregation method, a dispersion of fine particles (hereinafter referred to as “binder resin fine particles”) made of a binder resin produced by the emulsion polymerization method and a dispersion of colorant fine particles may be used as needed. The toner particle constituent dispersions such as the release agent fine particles are mixed together and slowly agglomerated while balancing the repulsive force of the fine particle surface by pH adjustment and the agglomeration force due to the addition of an aggregating agent made of an electrolyte. In this method, toner particles are produced by performing association while controlling the average particle size and particle size distribution, and simultaneously performing shape control by fusing the fine particles by heating and stirring.

  The binder resin fine particles may have a structure of two or more layers made of binder resins having different compositions. In this case, the first resin prepared by emulsion polymerization treatment (first-stage polymerization) according to a conventional method. It is possible to employ a method in which a polymerization initiator and a polymerizable monomer are added to a fine particle dispersion, and this system is polymerized (second stage polymerization).

  The cyan toner particles having a core-shell structure are prepared by associating, aggregating and fusing the fine particles of the binder resin to form the core particles and the colorant fine particles, and then producing a core particle dispersion. It is produced by adding a fine resin particle to form a shell layer therein and aggregating and fusing the fine shell resin particle on the surface of the core particle to form a shell layer covering the surface of the core particle. be able to.

A specific example of the production process when the cyan toner of the present invention is obtained by an emulsion polymerization aggregation method is shown below.
(1) A colorant fine particle dispersion preparation step for obtaining a dispersion of colorant fine particles in which colorant fine particles containing a cyan colorant are dispersed in an aqueous medium.
(2) A polymerizable monomer solution is prepared by dissolving or dispersing cyan toner particle constituent materials such as a release agent and a charge control agent as necessary in the polymerizable monomer to form a binder resin. This is added to an aqueous medium, mechanical energy is added to form oil droplets, and then a polymerization reaction is performed in the oil droplets by radicals from a radical polymerization initiator, thereby obtaining binder resin fine particles. Resin fine particle polymerization process,
(3) Addition of an aggregating agent to an aqueous medium in which binder resin fine particles and colorant fine particles are present, and by adjusting the temperature, the salting-out progresses, and at the same time, aggregation and fusion are performed, and cyan toner particles Salting out, agglomeration, fusing process to form,
(4) A filtration and washing step for separating cyan toner particles from the aqueous medium and removing the surfactant from the cyan toner particles.
(5) a drying step of drying the washed cyan toner particles;
(6) adding an external additive to the dried cyan toner particles;
Consists of

  Here, the “aqueous medium” refers to a medium composed of 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, and tetrahydrofuran, and alcohol-based organic solvents that do not dissolve the resulting resin are preferable.

In the colorant fine particle dispersion preparation step, a specific silicon phthalocyanine compound and other phthalocyanine compound as required are added to the aqueous medium, and mechanical energy is applied thereto to cause the colorant fine particles to be added to the aqueous medium. A dispersion of dispersed colorant fine particles is prepared.
The dispersion device for dispersing oil droplets by mechanical energy is not particularly limited, and general dispersion devices such as a ball mill, an attritor and a bead mill can be used. Among these, it is preferable to use a bead mill in the present invention because the dispersion rate is high and the treatment can be performed continuously.

The colorant fine particles in the dispersion prepared in the colorant fine particle dispersion preparation step preferably have a volume-based median diameter in the range of 20 to 1,000 nm, more preferably 20 to 140 nm, particularly preferably. 30-100 nm.
The method for controlling the volume-based median diameter of the colorant fine particles can be controlled, for example, by adjusting the magnitude of the mechanical energy described above.

[Surfactant]
In the colorant fine particle dispersion preparation step and / or the binder resin fine particle polymerization step, a surfactant may be added to the aqueous medium in order to stably disperse the fine particles in the aqueous medium. As the surfactant, various conventionally known ionic surfactants can be suitably used.

Preferable specific examples of the ionic surfactant include sulfonates (sodium dodecylbenzenesulfonate, sodium arylalkylpolyethersulfonate, 3,3-disulfonediphenylurea-4,4-diazo-bis-amino-8- Sodium naphthol-6-sulfonate, ortho-carboxybenzene-azo-dimethylaniline, 2,2,5,5-tetramethyl-triphenylmethane-4,4-diazo-bis-β-naphthol-6-sulfonate Sulfate ester 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) , Potassium stearate, magnesium stearate, calcium stearate, calcium oleate) and the like.
Nonionic surfactants can also be used. Specific examples of nonionic surfactants include polyethylene oxide, polypropylene oxide, a combination of polypropylene oxide and polyethylene oxide, esters of polyethylene glycol and higher fatty acids, and alkylphenol polyethylene. Examples include oxides, esters of higher fatty acids and polyethylene glycol, esters of higher fatty acids and polypropylene oxide, sorbitan esters, and the like.

(Polymerizable monomer)
The polymerizable monomer that should form the binder resin used in the binder resin fine particle polymerization step is a polymerizable monomer that can form a desired binder resin. Examples of polymerizable monomers in the case where a coalescence is desired include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-phenylstyrene, p-ethylstyrene, 2,4- Styrene or styrene styrene such as dimethyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene Derivatives; methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, isomethacrylate Methacrylic acid ester derivatives such as chill, tert-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate; acrylic Methyl acid, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, phenyl acrylate Acrylic acid ester derivatives such as acrylic acid, methacrylic acid, itaconic acid, fumaric acid, maleic acid and the like can be used. These polymerizable monomers can be used individually by 1 type or in combination of 2 or more types.
In addition, as polymerizable monomers, divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl Polyfunctional vinyls such as glycol diacrylate can also be used. By using these polyfunctional vinyls, a binder resin having a crosslinked structure can be obtained.
Of the above polymerizable monomers, styrene, butyl acrylate, 2-ethylhexyl acrylate, and methyl methacrylate are preferably used from the viewpoint of easy adjustment of the glass transition point and chargeability. When the polyester resin is contained in the resin, methacrylic acid or acrylic acid should be used from the viewpoint that the dispersion stability of the binder resin fine particles in the aqueous medium is improved and the size of the aggregated particles by the binder resin fine particles can be easily controlled. Is also preferable.

〔Release agent〕
The release agent used when the release agent is contained in the cyan toner particles constituting the cyan toner of the present invention is not particularly limited. For example, polyolefin wax such as polyethylene wax and polypropylene wax, paraffin wax , Long chain hydrocarbon waxes such as sazole wax, dialkyl ketone waxes such as distearyl ketone, carnauba wax, montan wax, trimethylolpropane tribehenate, pentaerythritol tetramyristate, pentaerythritol tetrastearate, Pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1,18-octadecanediol distearate, tristearyl trimellitic acid, Ester waxes such as stearyl maleate, ethylenediamine behenyl amide, an amide-based waxes such as trimellitic acid tristearyl amide.
The melting point of the wax constituting the release agent is usually 40 to 160 ° C, preferably 50 to 120 ° C, more preferably 60 to 90 ° C. When the melting point of the wax constituting the release agent is in the above range, the cyan toner obtained has sufficient heat-resistant storage stability and is stable without causing a cold offset phenomenon even when fixing at a low temperature. Thus, image formation can be performed.

  As a method for incorporating a release agent into cyan toner particles, as described above, a method in which the binder resin fine particles are configured to contain a release agent, or salting out, agglomeration, and fusion forming cyan toner particles is performed. In the process, a method of adding a dispersion liquid in which release agent fine particles are dispersed in an aqueous medium and salting out, aggregating, and fusing the binder resin fine particles, the colorant fine particles, and the release agent fine particles, etc. These methods may be combined.

  The content ratio of the release agent in the cyan toner particles is preferably 1 to 30% by mass, more preferably 5 to 20% by mass in the cyan toner particles. If the release agent content is too low, a sufficient offset prevention effect may not be obtained. On the other hand, if the release agent content is too high, the resulting cyan toner may be translucent or There is a risk of low color reproducibility.

[Charge control agent]
The charge control agent used in the case where the cyan toner particles constituting the cyan toner of the present invention contain a charge control agent is a substance that can give positive or negative charge by frictional charging and is colorless. Any known positively chargeable charge control agent and negatively chargeable charge control agent can be used.
The content ratio of the charge control agent in the cyan toner particles is preferably 0.01 to 30 parts by mass, more preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the binder resin.
Examples of the method for containing the charge control agent in the cyan toner particles include the same method as the method for containing the release agent described above.

(Polymerization initiator)
As the polymerization initiator used in the binder resin fine particle polymerization step, various known polymerization initiators can be used. Specifically, as the oil-soluble polymerization initiator, 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis-4-methoxy-2, Azo or diazo polymerization initiators such as 4-dimethylvaleronitrile; benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide, dicumyl Peroxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide , 2,2-bis- (4,4-t-butylperoxycyclohexyl) propane, peroxide-based polymerization initiators such as tris- (t-butylperoxy) triazine and polymers having a peroxide in the side chain An initiator etc. are mentioned.
Examples of the water-soluble polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate; azobisaminodipropane acetate, azobiscyanovaleric acid and salts thereof, hydrogen peroxide, and the like.

[Chain transfer agent]
In the binder resin fine particle polymerization step, a commonly used chain transfer agent can be used for the purpose of adjusting the molecular weight of the binder resin. The chain transfer agent is not particularly limited, and examples thereof include mercaptans such as octyl mercaptan, dodecyl mercaptan, tert-dodecyl mercaptan, n-octyl-3-mercaptopropionic acid ester, terpinolene, carbon tetrabromide and α-methylstyrene. Dimers and the like can be used.

  The binder resin fine particles in the dispersion prepared in the binder resin fine particle polymerization step preferably have a volume-based median diameter in the range of 50 to 300 nm.

[Flocculant]
Examples of the aggregating agent used in the salting out, aggregating, and fusing processes include alkali metal salts and alkaline earth metal salts. Examples of the alkali metal constituting the flocculant include lithium, potassium and sodium, and examples of the alkaline earth metal constituting the flocculant include magnesium, calcium, strontium and barium. Of these, potassium, sodium, magnesium, calcium, and barium are preferable. In addition, examples of the counter ions (anions constituting the salt) of these alkali metals or alkaline earth metals include chloride ions, bromide ions, iodide ions, carbonate ions, sulfate ions, and the like.

(External additive)
The above cyan toner particles can constitute the cyan toner of the present invention as they are, but in order to improve fluidity, chargeability, cleaning properties, etc., the cyan toner particles have a flow which is a so-called post-treatment agent. The cyan toner of the present invention may be constituted by adding external additives such as an agent and a cleaning aid.

As the post-treatment agent, for example, inorganic oxide fine particles composed of silica fine particles, alumina fine particles, titanium oxide fine particles, etc., inorganic stearate compound fine particles such as aluminum stearate fine particles, zinc stearate fine particles, or strontium titanate, titanium Inorganic titanic acid compound fine particles such as zinc acid are listed. These can be used individually by 1 type or in combination of 2 or more types.
These inorganic fine particles are preferably subjected to surface treatment with a silane coupling agent, a titanium coupling agent, a higher fatty acid, silicone oil or the like in order to improve heat-resistant storage stability and environmental stability.

  The total amount of these various external additives added is 0.05 to 5 parts by mass, preferably 0.1 to 3 parts by mass with respect to 100 parts by mass of the cyan toner. In addition, various external additives may be used in combination.

(Developer)
The cyan toner of the present invention can be used as a magnetic or non-magnetic one-component developer, but may be mixed with a carrier and used as a two-component developer. In the case where the cyan toner of the present invention is used as a two-component developer, the carrier includes conventionally known metals such as iron, magnetic materials such as ferrite and magnetite, and alloys of these with metals such as aluminum and lead. Magnetic particles made of a material can be used, and ferrite particles are particularly preferable. Further, as the carrier, a coat carrier in which the surface of magnetic particles is coated with a coating agent such as a resin, a binder type carrier in which magnetic fine powder is dispersed in a binder resin, or the like may be used.
The coating resin constituting the coat carrier is not particularly limited, and examples thereof include olefin resins, styrene resins, styrene-acrylic resins, silicone resins, ester resins, and fluorine resins. Moreover, it does not specifically limit as resin which comprises a resin dispersion type carrier, A well-known thing can be used, For example, a styrene-acrylic-type resin, a polyester resin, a fluororesin, a phenol resin etc. can be used.

  The volume-based median diameter of the carrier is preferably 15 to 100 μm, more preferably 25 to 80 μm. The volume-based median 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.

  Preferred carriers include a coated carrier using a silicone resin, a copolymer resin (graft resin) of an organopolysiloxane and a vinyl monomer or a polyester resin as a coating resin from the viewpoint of spent resistance. Coat carrier coated with resin obtained by reacting isocyanate with copolymer resin (graft resin) of organopolysiloxane and vinyl monomer from the viewpoint of durability, environmental stability and spent resistance Are preferable.

According to the cyan toner of the present invention, by having a specific silicon phthalocyanine compound as a cyan colorant, the specific silicon phthalocyanine compound is dispersed with high dispersibility in the cyan toner particles, thereby developing a highly saturated cyan color. In addition, excellent chargeability can be obtained, and an image can be formed with high stability.
This is because the specific silicon phthalocyanine compound has a high affinity for the carboxyl group on the surface of the binder resin fine particles because the group Z present in the axial position in the general formula (1) has a carboxyl group. Therefore, it is presumed that the reaggregation of the colorant fine particles is suppressed in the salting out, agglomeration, and fusing steps when the cyan toner is produced.

  As mentioned above, although embodiment of this invention was described concretely, embodiment of this invention is not limited to said example, A various change can be added.

  Hereinafter, specific examples of the present invention will be described, but the present invention is not limited thereto.

Example 1 Cyan Toner Production Example 1
(1) Preparation of Colorant Fine Particle Dispersion Solution 90 g of sodium dodecyl sulfate was dissolved in 1600 ml of ion-exchanged water with stirring, and 0.8 g of sodium hydroxide aqueous solution 0.01 mol / l was added to this solution to adjust the pH to 7.0. . While stirring this solution, gradually add 420 g of cyan colorant: a specific silicon phthalocyanine compound [1-1] in which two Zs in the general formula (1) are groups represented by the above formula (b). Created a solution. Next, this solution was put into a fine pulverizer “SC100” (manufactured by Nippon Coke Co., Ltd.), 900 g of zirconia beads φ3 mm was further added, and the dispersion dispersion treatment was performed for 5 hours at a flow rate of about 1 kg / min. A colorant fine particle dispersion [A] in which A] is dispersed was prepared. The particle diameter of the colorant fine particles [A] in the colorant fine particle dispersion [A] was measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.). It was 110 nm.

(2) Preparation of resin fine particle dispersion for core (2-1) First stage polymerization Polyoxyethylene-2-dodecyl ether sulfate in a 5 L reaction vessel equipped with a stirrer, temperature sensor, condenser, and nitrogen inlet A surfactant solution in which 4 parts by mass of sodium was dissolved in 3040 parts by mass of ion-exchanged water was charged, and the internal temperature was raised to 80 ° C. while stirring at a stirring speed of 230 rpm under a nitrogen stream. To this surfactant solution, an initiator solution in which 10 parts by mass of a polymerization initiator (potassium persulfate: KPS) was dissolved in 400 parts by mass of ion-exchanged water was added to a temperature of 75 ° C., and then 532 parts by mass of styrene. A monomer mixture consisting of 200 parts by mass of n-butyl acrylate, 68 parts by mass of methacrylic acid, and 16.4 parts by mass of n-octyl mercaptan was added dropwise over 1 hour, and the system was heated at 75 ° C. for 2 hours. Then, polymerization (first stage polymerization) was carried out by stirring, whereby a dispersion [A1] of resin particles [A1] was prepared. The weight average molecular weight (Mw) of the resin particles [A1] was 16,500.

(2-2) Second stage polymerization (formation of intermediate layer)
In a flask equipped with a stirrer, a monomer mixture comprising 101.1 parts by mass of styrene, 62.2 parts by mass of n-butyl acrylate, 12.3 parts by mass of methacrylic acid, and 1.75 parts by mass of n-octyl mercaptan As a release agent, 93.8 parts by mass of paraffin wax “HNP-57” (manufactured by Nippon Seiwa Co., Ltd.) was added, and the mixture was heated to 90 ° C. and dissolved to prepare a monomer solution.
On the other hand, a surfactant solution in which 3 parts by mass of sodium polyoxyethylene-2-dodecyl ether sulfate was dissolved in 1560 parts by mass of ion-exchanged water was heated to 98 ° C., and the resin particles [A1 After the addition of 32.8 parts by weight of the dispersion [A1] in terms of solid content, a single amount in which the wax was dissolved by a mechanical disperser “CLEARMIX” (manufactured by M Technique Co., Ltd.) having a circulation path. The body solution was mixed and dispersed for 8 hours to prepare a dispersion containing emulsified particles having a dispersed particle size of 340 nm.
Next, an 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 this dispersion, and the system is polymerized by heating and stirring at 98 ° C. for 12 hours. Two-stage polymerization) was performed, thereby preparing a dispersion [A2] of resin particles [A2]. The weight average molecular weight (Mw) of the resin particles [A2] was 23,000.

(2-3) Third stage polymerization (formation of outer layer)
An 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 dispersion [A2] of the resin particles [A2], and styrene is added at a temperature of 80 ° C. A monomer mixed solution consisting of 293.8 parts by mass, n-butyl acrylate 154.1 parts by mass, and n-octyl mercaptan 7.08 parts by mass was added dropwise over 1 hour. After completion of the dropwise addition, polymerization (third-stage polymerization) is performed by heating and stirring for 2 hours, and then cooled to 28 ° C., whereby the core resin fine particles [1] are dispersed. Liquid [1] was prepared. The core resin fine particles [1] have a weight average molecular weight (Mw) of 26,800, a glass transition point (Tg) of 28.1 ° C., and the core resin fine particles [1] have a volume-based median diameter of 125 nm. Met.

(3) Preparation of resin fine particle dispersion for shell layer 4 parts by mass of sodium polyoxyethylene-2-dodecyl ether sulfate was added to ion-exchanged water in a 5 L reaction vessel equipped with a stirrer, temperature sensor, condenser, and nitrogen inlet. The surfactant solution dissolved in 3040 parts by mass was charged, and the internal temperature was raised to 80 ° C. while stirring at a stirring speed of 230 rpm under a nitrogen stream. To this surfactant solution, an initiator solution in which 10 parts by mass of a polymerization initiator (potassium persulfate: KPS) was dissolved in 400 parts by mass of ion-exchanged water was added to a temperature of 75 ° C., and then 624 parts by mass of styrene. A monomer mixture consisting of 120 parts by mass of butyl acrylate, 56 parts by mass of methacrylic acid, and 16.4 parts by mass of n-octyl mercaptan was dropped over 1 hour, and this system was heated and stirred at 75 ° C. for 2 hours. Thus, polymerization (first-stage polymerization) was performed, whereby a shell layer resin fine particle dispersion [1] in which the resin fine particles for the shell layer were dispersed was prepared. The resin fine particles for shell layer had a weight average molecular weight (Mw) of 16,500.

(4) Preparation of toner particles In a 5 L reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introducing device, 300 g of the resin fine particle dispersion for core [1] in terms of solid content and 1400 g of ion-exchanged water Then, a solution in which 120 g of the colorant fine particle dispersion [A] was dissolved in 120 ml of ion-exchanged water was added, the liquid temperature was adjusted to 30 ° C., and then the pH was adjusted to 8 by adding a 5N aqueous sodium hydroxide solution. Next, an aqueous solution in which 35 g of magnesium chloride was dissolved in 35 ml of ion-exchanged water was added over 10 minutes at 30 ° C. with stirring. After holding for 3 minutes, the temperature was raised and the system was heated to 75 ° C. over 60 minutes, and the particle growth reaction was continued while maintaining 75 ° C. In this state, the particle size of the associated particles was measured by “Multisizer 3” (manufactured by Beckman Coulter), and when the volume-based median diameter became 2.0 μm, the resin fine particle dispersion for shell layer [ 1] was added in terms of solid content, and the particle growth reaction was continued. When the particle size reaches 6.5 μm, an aqueous solution in which 150 g of sodium chloride is dissolved in 600 ml of ion-exchanged water is added to stop particle growth, and the mixture is heated and stirred at a liquid temperature of 75 ° C. as a fusion process. Thus, the fusion between the particles was advanced. Thereafter, the solution was cooled to 30 ° C., hydrochloric acid was added to adjust the pH to 7.0, stirring was stopped, and toner particles [1] were obtained.
The produced toner particles [1] are solid-liquid separated with a basket type centrifuge “MARK III model number 60 × 40” (manufactured by Matsumoto Kikai Co., Ltd.) to form a wet cake of the particles. The basket-type centrifuge was washed with ion exchange water at 45 ° C. until the electrical conductivity of the filtrate reached 1 μS / cm, and then transferred to “Flash Jet Dryer” (manufactured by Seishin Enterprise Co., Ltd.). It dried until it became the mass%.
To the dried toner particles [1], 1% by mass of hydrophobic silica (number average primary particle size = 12 nm, hydrophobicity = 68) and hydrophobic titanium oxide (number average primary particle size = 20 nm, hydrophobicity = 63) was added and mixed with a “Henschel mixer” (manufactured by Mitsui Miike Chemical Co., Ltd.). Thereafter, coarse particles were removed using a sieve having an opening of 45 μm to produce cyan toner [1].

[Examples 2 to 8, Comparative Examples 1 to 5: Cyan Toner Production Examples 2 to 13]
According to Table 1, the type (specific silicon phthalocyanine compound) and content of the cyan colorant were used in (1-2) Colorant fine particle dispersion step of (1) Preparation of colorant fine particle dispersion in Cyan toner production example 1. Cyan toners [2] to [13] were produced in the same manner except that the changes were made. Cyan toners [12] and [13] are for comparison.

(Preparation of developer)
Each of the cyan toners [1] to [13] is mixed with a volume-based median diameter 60 μm ferrite carrier coated with a silicone resin so that the density of the cyan toner is 6% by mass, and the developer [1 ] To [13] were prepared.

[Evaluation]
(1) Saturation Using the above developers [1] to [13], using a full color high-speed multifunction machine “bizhub PRO C6500” (manufactured by Konica Minolta Business Technologies), paper “POD gloss coat basis weight 128 g / m” ² ”(manufactured by Oji Paper Co., Ltd.), a solid monochrome image having a size of 2 cm × 2 cm was formed with a toner adhesion amount of 4.0 g / m ² . L ^* a ^* b ^* of this solid image was measured with “Spectrolina / Scan Bundle” (manufactured by Gretag Macbeth) under the following measurement conditions, and chroma C ^* was calculated and evaluated according to the following formula (C). The results are shown in Table 1.
If the saturation C ^* is 58 or more, it is determined to be an acceptable level without any practical problem.
Formula (C): Saturation C ^* = [(a ^* ) ² + (b ^* ) ² ] ^1/2
-Measurement conditions-
-Light source: D50 light source-Observation field of view: 2 °
・ Concentration: ANSI T
・ White standard: Abs
・ Filter: UV Cut
・ Measurement mode: Reflectance ・ Language: Japan

(2) Image Stability Using the above developers [1] to [13], a full color high-speed multifunction machine “bizhub PRO C6500” (manufactured by Konica Minolta Business Technologies, Inc.) is used and a low temperature and low humidity environment (temperature: 10 ° C., humidity) 15% RH) and a high-temperature and high-humidity environment (temperature 30 ° C., humidity 85% RH), after continuously forming 1,000 images with a C / W ratio of 20%, The image density and fog on the photoreceptor were visually observed and evaluated according to the following evaluation criteria.
-Evaluation criteria-
○: No decrease in image density or fogging occurred (passed).
Δ: Image density reduction and / or fogging occurred slightly, but at a level with no practical problem (pass).
X: Image density reduction and fogging occurred, and there were practical problems (failed).

As described above, according to the developers [1] to [11] containing the silicon phthalocyanine compound according to the present invention, it was confirmed that sufficient saturation and high image stability can be obtained.

Claims (2)

Consists of cyan toner particles containing a binder resin and a cyan colorant,
A cyan toner for developing electrostatic images, wherein the cyan colorant contains a silicon phthalocyanine compound represented by the following general formula (1).

[In the above formula, two Z are each, indicates any of the groups represented by the following formula (a) ~ formula (j), at least one Z is Formula (b), Formula (f) or It is group represented by Formula (i) . ]

2. The cyan toner for developing electrostatic images according to claim 1, wherein the cyan colorant contains a phthalocyanine compound other than the silicon phthalocyanine compound .