JP5673056B2 - Toner for electrostatic charge development, developer for electrostatic charge development and image forming method - Google Patents

Description

  The present invention relates to an electrostatic charge developing toner, an electrostatic charge developing developer, and an image forming method.

  In image formation by electrophotography, a toner image is generally transferred onto a medium such as transfer paper and then fixed onto the medium. Fixing methods include heat fixing, solvent fixing, and pressure fixing. Among them, the pressure fixing method that fixes only by pressure consumes less power and can be started quickly, following the high-speed fixing method. It has the advantages that the device is simple.

  An electrostatic charge having a toner containing a binder resin and a colorant in order to provide a developer for developing an electrostatic charge image that can be fixed at low temperature, has excellent storage stability and fluidity, and provides a clear and fog-free image. In the developer for image development, the binder resin is an AB type block copolymer having an A segment and a B segment, and the A segment includes a styrene monomer, an acrylic monomer, a methacrylic monomer, and a diene monomer. Having a copolymer structure having at least one monomer selected from the group consisting of: the B segment is selected from the group consisting of styrene monomers, acrylic monomers, methacrylic monomers and diene monomers A copolymer structure having at least one monomer, and the A segment and the B segment are different copolymers. Electrostatic image developer characterized by having a combined structure is disclosed (e.g., see cited references 1).

  Also provided is a toner composition that has a lower melting temperature, is fixed with lower melting energy, consumes less powder during melting, and has superior tribocharging properties that extend the life of the selected melting system To this end, a toner composition is disclosed that includes chemically bonded multi-block liquid glass resin particles and pigment particles having a glass transition temperature of about 20 to about 65 ° C. (see, for example, Reference 2).

  In addition, to provide a microcapsule toner that is fixed instantaneously by applying pressure, the fixed image is not peeled off or destroyed by external force, and the fixability does not deteriorate even when stored for a long period of time. In a microcapsule toner comprising a core material containing a fixing component and an outer shell covering the core material, the fixing component contains a resin and a micro phase consisting of a dispersed phase having a glass transition temperature of 20 ° C. or lower and a liquid continuous phase. A block copolymer and / or graft copolymer comprising two or more components having a phase separation structure and at least one component compatible with the dispersed phase and the remaining components compatible with the continuous phase. There is disclosed a microcapsule toner containing the same (for example, see Patent Document 3).

In addition, an electrostatic charge image that can be fixed at low temperature without causing an offset phenomenon or a wrapping phenomenon around a heat roller at the time of thermal contact fixing, and has little toner filming on the surface of the carrier powder or the toner holder during development. In order to provide a developing toner, a powdered electrostatic charge image developing toner comprising a colorant and a binder contains a thermoplastic elastomer as the binder, and the storage elastic modulus of the toner at 200 ° C. However, there is disclosed a toner for developing an electrostatic charge image, characterized in that it is 8.0 × 10 ^{5 to} 1.0 × 10 ⁴ (dyne / cm ² ) (for example, see Patent Document 4).

  In addition, in order to provide a resin composition for a toner excellent in low-temperature fixability, offset resistance and storage stability, a vinyl copolymer having a styrene monomer and a (meth) acrylate monomer as structural units. In the resin composition for a toner mainly composed of a polymer and a low melting crystalline compound, the vinyl copolymer comprises a low molecular weight vinyl copolymer and a high molecular weight vinyl copolymer, A resin composition for toner, wherein the low molecular weight vinyl copolymer and / or the high molecular weight vinyl copolymer contains a side chain capable of forming an aggregated structure with the low melting point crystalline compound. The thing is disclosed (for example, refer patent document 5).

  In addition, in order to provide an image forming method that can be fixed by heating at room temperature or low temperature and has high image quality and high reliability, the toner includes a block copolymer having a crystalline polyester block and an amorphous polyester block, An image forming method is disclosed in which the maximum pressure during fixing is 1 MPa or more and 10 MPa or less (see, for example, Patent Document 6).

  In addition, in order to provide a toner for developing an electrostatic charge image that can reduce the fixing energy even on thick paper while achieving both high image quality and reliability, the electrostatic charge image development obtained by aggregating resin particles having a core-shell structure is provided. The toner constituting the core and the shell is an amorphous resin, and the glass transition point of the resin constituting the core is different from the glass transition point of the resin constituting the shell by 20 ° C. or more. An electrostatic charge image developing toner is disclosed in which an acidic or basic polar group or an alcoholic hydroxyl group is contained in the resin constituting the toner (see, for example, Patent Document 7).

  In addition, in order to provide a toner for developing an electrostatic charge image that can reduce the fixing energy even on thick paper while achieving both high image quality and reliability, the electrostatic charge image development obtained by aggregating resin particles having a core-shell structure is provided. The toner constituting the core and the shell contains a polycondensation resin, and the difference between the glass transition point of the resin constituting the core and the glass transition point of the resin constituting the shell is 20 ° C. or more. A characteristic toner for developing an electrostatic image is disclosed (for example, see Patent Document 8).

  In addition, resin particles having a core-shell structure are agglomerated in order to provide an image forming method that is excellent in pressure fixing performance, hardly causes image defects due to adhesion (filming) of toner to a photoreceptor, and can provide an excellent image. Using the obtained electrostatic charge image developing, the resin constituting the core and the shell is an amorphous resin, and the glass transition temperature of the resin constituting the core and the glass transition temperature of the resin constituting the shell are 20 ° C. Unlike the above, the resin constituting the shell contains an acidic or basic polar group or an alcoholic hydroxyl group, and the fixing step is a step of fixing the transferred toner image by applying pressure without heating. An image forming method is disclosed (for example, see Patent Document 9).

JP 05-019532 A Japanese Patent Laid-Open No. 06-011891 JP 06-0119182 A Japanese Patent Application Laid-Open No. 07-271096 JP 09-138521 A JP 2007-114635 A JP 2007-310064 A JP 2007-322953 A JP 2009-53318 A

  An object of the present invention is to provide a toner for developing an electrostatic charge that can be fixed by applying pressure without heating.

  That is, the invention according to claim 1 includes an A block having a polymer structure containing a repeating unit derived from a styrenic monomer and a B block having a polymer structure having a glass transition temperature (Tg) of −10 ° C. or lower. An electrostatic charge developing toner comprising an ABA type triblock copolymer having a number average molecular weight of 50,000 to 500,000 and at least one selected from the group consisting of paraffinic oil, naphthenic oil and aromatic oil It is.

  The invention according to claim 2 is the electrostatic charge developing toner according to claim 1, wherein the B block has a polymer structure containing a repeating unit derived from a (meth) acrylic monomer.

  In the invention according to claim 3, the glass transition temperature Tg (A) of the A block and the glass transition temperature Tg (B) of the B block satisfy a relationship of Tg (A) ≧ Tg (B) + 80 ° C. The toner for developing an electrostatic charge according to claim 1 or 2.

  In the invention according to claim 4, the ratio A / B between the number average molecular weight A of the A block and the number average molecular weight B of the B block contained in the ABA type triblock copolymer is 0.4 or more and 4 or less. The electrostatic charge developing toner according to claim 1, wherein the toner is an electrostatic charge developing toner.

  A fifth aspect of the present invention is an electrostatic charge developing developer comprising the electrostatic charge developing toner according to any one of the first to fourth aspects.

The invention according to claim 6 is a latent image forming step of forming an electrostatic charge image on the surface of the latent image holding member,
A developing step of developing the electrostatic image formed on the surface of the latent image holding member with the electrostatic charge developing developer according to claim 5 to form a toner image;
A transfer step of transferring the toner image formed on the surface of the latent image carrier to the surface of the transfer target;
And a fixing step of pressure-fixing the toner image transferred to the surface of the transfer material with a maximum pressure of 1 MPa or more and 10 MPa or less.

  According to the first to fourth aspects of the invention, there is provided an electrostatic charge developing toner that can be fixed by pressure without heating.

  According to the fifth aspect of the present invention, there is provided a developer for electrostatic charge development that can be fixed by pressure without heating.

  According to the sixth aspect of the present invention, there is provided an image forming method capable of fixing by applying pressure without heating.

It is a conceptual diagram which shows the ABA type | mold triblock copolymer of this embodiment. 1 is a cross-sectional view schematically showing a basic configuration of a preferred embodiment of an image forming apparatus capable of performing an image forming method of the present embodiment.

  The electrostatic charge developing toner, electrostatic charge developing developer and image forming method of the present invention will be described in detail below.

<Toner for electrostatic charge development>
The electrostatic charge developing toner according to the exemplary embodiment (hereinafter sometimes simply referred to as “toner”) has an A block having a polymer structure containing a repeating unit derived from a styrenic monomer and a glass transition temperature (Tg) of −10. Selected from the group consisting of an ABA triblock copolymer having a B block having a polymer structure exhibiting a temperature of ℃ or less and having a number average molecular weight of 50,000 or more and 500,000 or less, paraffinic oil, naphthenic oil and aromatic oil And at least one kind.

The toner of the present exemplary embodiment can be fixed by applying pressure without heating. The mechanism of fixing by pressing is not clear, but is presumed as follows.
FIG. 1 is a conceptual diagram showing an ABA type triblock copolymer of the present embodiment. In the ABA triblock copolymer of this embodiment, A blocks are pseudo-crosslinked to form a physical crosslinked body. The A block has a polymer structure containing a repeating unit derived from a styrenic monomer, and the aromatic ring contained in the styrenic monomer is considered to contribute to the formation of a physical crosslinked product. By forming a physical crosslinked body, the ABA type triblock copolymer forms a three-dimensional network structure as shown in FIG. This physical crosslinked body does not form a chemical bond and is easily broken by pressure. When the physical crosslinked body is destroyed, the ABA type triblock copolymer becomes plastic. In the state where no pressure is applied, the ABA type triblock copolymer exhibits a hardness suitable for the toner and does not cause blocking or the like. Further, the toner according to the exemplary embodiment includes at least one so-called process oil selected from the group consisting of paraffinic oil, naphthenic oil, and aromatic oil. The process oil is incorporated in a three-dimensional network structure formed of an ABA type triblock copolymer, and the incorporated process oil does not contribute to the fluidity of the resin and is plastic to the ABA type triblock copolymer. give.
Here, in order to fix the toner image formed on the surface of the transfer medium with the toner of the present embodiment, when the toner image is pressed under pressure, the physical crosslinked body is destroyed and the ABA type triblock copolymer is destroyed. The process oil taken in the three-dimensional network structure formed in (1) is released from the network structure. Then, the discharged process oil acquires free fluidity as a liquid and reduces the viscosity reduction of the entire resin, whereby the toner image is fixed on the surface of the transfer target. At this time, part of the process oil is absorbed by the transfer target. When the pressurization is completed, the physical cross-linked product of the ABA type triblock copolymer is re-formed, and the plasticity of the toner image is lowered. As a result, it is assumed that the toner image is stably fixed on the surface of the transfer target.

  Next, each component constituting the toner of the exemplary embodiment will be described. The toner of the present exemplary embodiment contains a specific ABA type triblock copolymer, process oil, and other components such as a colorant and a release agent used as necessary.

-ABA type triblock copolymer-
The toner of this embodiment has an A block having a polymer structure containing a repeating unit derived from a styrene monomer and a B block having a polymer structure having a glass transition temperature (Tg) of −10 ° C. or less. An ABA type triblock copolymer having an average molecular weight of 50,000 or more and 500,000 or less is contained. The ABA type triblock copolymer functions as a binder resin for toner.

As the styrenic monomer serving as a base of the polymer structure contained in the A block, styrene derivatives such as styrene, O-methylstyrene, m-methylstyrene, and p-methylstyrene are used. Of these, styrene is desirable. The A block may contain a repeating unit derived from another monomer other than the styrene monomer. Examples of other monomers include acrylic acid esters such as acrylic acid and butyl acrylate, and methacrylic acid esters such as methacrylic acid and butyl methacrylate.
The ratio of the repeating unit derived from the styrene monomer and the repeating unit derived from the other monomer in the A block is preferably 70:30 to 100: 0, more preferably 75:25 to 99: 1 on a molar basis.

  In this embodiment, the B block is not particularly limited as long as it has a polymer structure in which the Tg is −10 ° C. or lower (even if the crystal structure having a melting point is T−10 ° C. or lower). For example, the polymer structure may include a repeating unit derived from a (meth) acrylic monomer, an olefin monomer, or the like. Among these, a polymer structure including a repeating unit derived from a (meth) acrylic monomer is desirable. Here, the above-mentioned “(meth) acrylic monomer” is an abbreviated notation indicating that the structure of both a methacrylic monomer and an acrylic monomer can be taken.

Specific examples of the (meth) acrylic monomer include butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, stearyl acrylate, behenyl acrylate, and the like. Among these, butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, and stearyl acrylate are preferable.
The monomers used for forming the B block may be used alone or in combination of two or more.

  The number average molecular weight of the ABA type triblock copolymer is set to 50,000 or more and 500,000 or less. If the number average molecular weight is less than 50000, the physical strength of the resin may be reduced, and problems such as toner destruction due to in-machine stress as a developer may occur. When the number average molecular weight exceeds 500,000, problems such as a decrease in fixability due to pressurization may occur. The number average molecular weight of the ABA type triblock copolymer is preferably from 50,000 to 300,000, and more preferably from 55,000 to 250000.

The number average molecular weight Mn was measured by gel permeation chromatography (GPC) under the conditions described below. At a temperature of 40 ° C., a solvent (tetrahydrofuran) is flowed at a flow rate of 1.2 ml per minute, and 3 mg of a tetrahydrofuran sample solution having a concentration of 0.2 g / 20 ml is injected as a sample weight for measurement. When measuring the molecular weight of a sample, select the measurement conditions that fall within the range in which the logarithm of the molecular weight of the prepared calibration curve and the count number are linear, using several monodisperse polystyrene standard samples. . The reliability of the measurement results was confirmed by the NBS706 polystyrene standard sample obtained under the above-described measurement conditions having a weight average molecular weight Mw = 28.8 × 10 ⁴ and a number average molecular weight Mn = 13.7 × 10 ^4. can do. Further, as the GPC column, TSK-GEL, GMH (manufactured by Tosoh Corporation), etc. satisfying the above conditions were used.

In the present embodiment, it is desirable that the glass transition temperature Tg (A) of the A block and the glass transition temperature Tg (B) of the B block satisfy the relationship of Tg (A) ≧ Tg (B) + 80 ° C. When the A block and the B block satisfy the above relationship, a desirable pressure plasticization behavior is observed when the toner image is pressure-fixed.
The relationship between Tg (A) and Tg (B) is more preferably Tg (A) ≧ Tg (B) + 60 ° C.

The glass transition temperature of A block and B block can be measured by a well-known method, for example, can be measured by the method (DSC method) prescribed | regulated to ASTMD3418-82.
The glass transition temperature by DSC of the resin is measured according to ASTM D3418 using a differential scanning calorimeter (DSC-50) manufactured by Shimadzu Corporation equipped with an automatic tangential processing system. The measurement conditions are shown below.
Sample: 3 to 15 mg, preferably 5 to 10 mg
Measurement method: Place the sample in an aluminum pan, and use an empty aluminum pan as a reference.
Temperature curve: Temperature increase I (20 ° C. to 180 ° C., temperature increase rate 10 ° C./min)
The glass transition temperature is measured from the endothermic curve measured at the time of temperature rise in the above temperature curve. The glass transition temperature is a temperature at which the differential value of the endothermic curve is maximized.

In the present embodiment, the ratio A / B between the number average molecular weight A of the A block and the number average molecular weight B of the B block contained in the ABA type triblock copolymer is preferably 0.4 or more and 4 or less. . The number average molecular weight of the A block is the total number average molecular weight of two A blocks contained in the ABA type triblock copolymer. If the ratio A / B is 0.4 or more, there is an advantage that sufficient image strength can be obtained after toner fixing. On the other hand, if the ratio A / B is 4 or less, there is an advantage that uniformity of toner fixability when pressurized is obtained.
The ratio A / B is more preferably 0.5 or more and 3.5 or less.

The ratio A / B is calculated from the number average molecular weight of the A block after polymerization and the number average molecular weight of the B block as follows.
A / B = (Number average molecular weight of A block) / (B block number average molecular weight)

The method for synthesizing the ABA type triblock copolymer is not particularly limited, but it is desirable to use living radical polymerization.
As a technique used for living radical polymerization, for example, a known technique such as NMRP (Nitroxide Mediated Radial Polymerization), ATRP (Atom Transfer Radical Polymerization, RAFT (Reversible Addition Fragmentation Transfer)) can be used.
For the living polymerization, a general polymerization method such as a homogeneous reaction such as bulk polymerization or solution polymerization or a heterogeneous reaction such as a mini-emulsion method can be applied, and the present embodiment is not limited at all. In addition, in the polymerization of the ABA type triblock structure by the living radical polymerization, when one active radical is present at the end of the polymer chain during the polymerization, the B monomer is chain-extended after the living polymerization of the A monomer. And, finally, a three-stage polymerization method in which chain extension is again performed with the A monomer, and by previously forming an adduct of a divinyl group and a living control agent used in the NMRP, ATRP, and RAFT, from both ends of the polymer during polymerization (A total of two active radicals at both ends of the polymer chain) can be polymerized, and after the B monomer is polymerized in the first stage, the A monomer is further added so that the chain extension of the A monomer from both ends of the B polymer can be achieved. Any method can be used, such as a method of manufacturing in two stages.
In the present invention, a two-stage method using a control agent adduct prepared in advance from the industrial viewpoint is particularly preferred. For confirmation of these structures, there is usually a deviation between the charged amount of the monomer and the theoretical molecular weight calculated from the polymerization initiator or the control agent and the measured value, and the deviation from the theoretical value of the molecular weight increase behavior with respect to the conversion rate by chain extension ( Usually, within 10%), molecular weight distribution information based on weight average molecular weight and number average molecular weight (usually 2 or less) can be used.

-Process oil-
The toner of this embodiment contains at least one process oil selected from the group consisting of paraffinic oil, naphthenic oil, and aromatic oil.
The process oil may be used alone or in combination of two or more.

  Specific examples of the paraffinic oil include Diana Process Oil PW series (manufactured by Idemitsu Kosan Co., Ltd.). Among these, Diana process oil PW90 is desirable.

  Specific examples of the naphthenic oil include, for example, Diana Process Oil NP series (produced by Idemitsu Kosan Co., Ltd.). Among these, Diana process oil NP23 is desirable.

  Specific examples of the aromatic oil include Diana process oil AC series. Among these, Diana process oil AC12 is desirable.

  The content of the process oil is preferably 5 parts by mass or more and 50 parts by mass or less, and more preferably 10 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the ABA type triblock copolymer.

  The process oil is preferably impregnated in an ABA type triblock copolymer. Examples of the method of impregnating the ABA type triblock copolymer with the process oil include a method in which the process oil is added to the ABA type triblock copolymer and kneaded.

-Other ingredients-
The toner according to the exemplary embodiment may include other binder resins other than the ABA triblock copolymer, a colorant, a release agent, an internal additive, a charge control agent, an inorganic powder (inorganic particles), if necessary. You may contain various components, such as an organic particle.

  Examples of other binder resins that may be used in this embodiment include polyethylene, polypropylene, polyester, polyurethane, epoxy resin, silicone resin, polyamide, and the like.

The toner of this embodiment may contain a colorant. Coloring agents include magnetic powders such as magnetite and ferrite, carbon black, aniline blue, caryl blue, chrome yellow, ultramarine blue, DuPont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, and lamp black. Rose Bengal, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 57: 1, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 17, C.I. I. Pigment blue 15: 1, C.I. I. Pigment Blue 15: 3, Pigment Green 7, Pigment Green 36, Pigment Orange 61, etc. are representative examples.
The content of the colorant is preferably 1% by mass to 30% by mass, and more preferably 3% by mass to 15% by mass.

The toner of the exemplary embodiment may contain a release agent. Examples of the release agent to be contained include low molecular weight polyolefins such as polyethylene, polypropylene, and polybutene, silicones that exhibit a softening point by heating, and olein. Fatty acid amides such as acid amides, erucic acid amides, ricinoleic acid amides, stearic acid amides, plant waxes such as carnauba wax, rice wax, candelilla wax, tree wax, jojoba oil, beeswax, etc. Mineral waxes such as natural animal waxes, montan waxes, ozokerites, ceresins, microcrystalline waxes, Fischer-Tropsch waxes, ester waxes such as fatty acid esters, montanic acid esters, carboxylic acid esters, and their modifications Such as things These release agents may be used alone or in combination of two or more.
As content of a mold release agent, 1 to 20 mass% is desirable, and 5 to 15 mass% is further more desirable.

  Examples of the internal additive include metals such as ferrite, magnetite, reduced iron, cobalt, nickel and manganese, alloys, and magnetic materials such as compounds containing these metals. Examples of the charge control agent include quaternary ammonium salt compounds, nigrosine compounds, dyes composed of complexes of aluminum, iron, chromium, and triphenylmethane pigments. The inorganic powder is added mainly for the purpose of adjusting the viscoelasticity of the toner. For example, alumina, titania, calcium carbonate, magnesium carbonate, calcium phosphate, cerium oxide, etc. All inorganic particles used as an external additive are included.

The toner according to the exemplary embodiment may include an external additive. Examples of the external additive include known inorganic particles such as silica particles, titanium oxide particles, alumina particles, cerium oxide particles, and carbon black whose surfaces have been hydrophobized, and polymer particles such as polycarbonate, polymethyl methacrylate, and silicone resin. Particles are used.
The content of the external additive is preferably 0.5% by mass or more and 20% by mass or less, and more preferably 1% by mass or more and 5% by mass or less.

The volume average particle size of the toner according to the exemplary embodiment is preferably in the range of 4 μm to 9 μm, more preferably in the range of 4.5 μm to 8.5 μm, and still more preferably in the range of 5 μm to 8 μm. . When the volume average particle size is smaller than 4 μm, the toner fluidity is lowered, and the chargeability of each particle tends to be lowered. Further, since the charge distribution is widened, fogging on the background, toner spillage from the developing device, and the like are likely to occur. On the other hand, if the particle size is less than 4 μm, scattering of the low-charged toner during fixing may not be suppressed, and cleaning performance may be extremely difficult. When the volume average particle size is larger than 9 μm, the resolution may be lowered.
Here, the volume average particle diameter is measured using Coulter Multisizer II (manufactured by Coulter), and the electrolyte is measured using ISOTON-II (manufactured by Coulter).

Furthermore, it is desirable that the toner of the present exemplary embodiment has a spherical shape with a shape factor SF1 in the range of 110 to 140. When the shape is spherical in this range, transfer efficiency and image density are improved, and a high-quality image is formed.
The shape factor SF1 is more preferably in the range of 110 to 130.

Here, the shape factor SF1 is obtained by the following equation (1).
SF1 = (ML ² / A) × (π / 4) × 100 (1)
In the above formula (1), ML represents the absolute maximum length of the toner particles, and A represents the projected area of the toner particles.

  The SF1 is quantified mainly by analyzing a microscope image or a scanning electron microscope (SEM) image using an image analyzer, and is calculated as follows, for example. That is, an optical microscope image of particles scattered on the surface of the slide glass is taken into a Luzex image analyzer through a video camera, and the maximum length and projected area of 100 particles are obtained, calculated by the above equation (1), and the average value is calculated. It is obtained by seeking.

<Toner production method>
The method for producing the toner according to the exemplary embodiment is not particularly limited, and the toner is produced by a known dry method such as a kneading / pulverizing method or a wet method such as an emulsion aggregation method or a suspension polymerization method. Among these methods, an emulsion aggregation method that can easily produce a toner having a core-shell structure is desirable. Hereinafter, a method for producing a toner by the emulsion aggregation method will be described in detail.

  In the emulsification aggregation method according to the present embodiment, the raw material constituting the toner is emulsified to form resin particles (emulsion particles), the aggregation step of forming aggregates including the resin particles, and the aggregates are fused. And a fusion step.

(Emulsification process)
For example, the resin particle dispersion may be produced by applying a shearing force to a solution obtained by mixing an aqueous medium and a binder resin with a disperser. At that time, particles may be formed by heating to lower the viscosity of the resin component. A dispersant may be used for stabilizing the dispersed resin particles.
Furthermore, if the resin is oily and dissolves in a solvent with a relatively low solubility in water, the resin is dissolved in those solvents and dispersed in water together with a dispersant and a polymer electrolyte, and then heated or decompressed. By evaporating the solvent, a resin particle dispersion is produced.

  In the present embodiment, it is preferable to use an ABA triblock copolymer impregnated with process oil as the binder resin (ABA triblock copolymer) used in the emulsification step.

Examples of the aqueous medium include water such as distilled water and ion-exchanged water; alcohols; and the like. Water is preferable.
Examples of the dispersant used in the emulsification step include water-soluble polymers such as polyvinyl alcohol, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, sodium polyacrylate, and sodium polymethacrylate; sodium dodecylbenzenesulfonate, Anionic surfactants such as sodium octadecyl sulfate, sodium oleate, sodium laurate, potassium stearate, cationic surfactants such as laurylamine acetate, stearylamine acetate, lauryltrimethylammonium chloride, amphoteric such as lauryldimethylamine oxide Ionic surfactant, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene Surfactants such as nonionic surfactants such as alkyl amines; and the like are; tricalcium phosphate, aluminum hydroxide, calcium sulfate, calcium carbonate, inorganic salts such as barium carbonate.

  Examples of the disperser used for preparing the emulsion include a homogenizer, a homomixer, a pressure kneader, an extruder, and a media disperser. As the size of the resin particles, the average particle diameter (volume average particle diameter) is desirably 1.0 μm or less, more desirably 60 nm or more and 300 nm or less, and further desirably 150 nm or more and 250 nm or less. . If it is less than 60 nm, the resin particles become stable particles in the dispersion, and thus aggregation of the resin particles may be difficult. On the other hand, if it exceeds 1.0 μm, the cohesiveness of the resin particles is improved and it becomes easy to prepare toner particles, but the particle size distribution of the toner may be widened.

  In preparing the release agent dispersion, the release agent is dispersed in water together with an ionic surfactant, a polymer electrolyte such as a polymer acid or a polymer base, and then heated to a temperature equal to or higher than the melting temperature of the release agent. Dispersion treatment is performed using a homogenizer or a pressure discharge type disperser to which a strong shearing force is applied while heating. Through the above treatment, a release agent dispersion is obtained. During the dispersion treatment, an inorganic compound such as polyaluminum chloride may be added to the dispersion. Examples of desirable inorganic compounds include polyaluminum chloride, aluminum sulfate, highly basic polyaluminum chloride (BAC), polyaluminum hydroxide, and aluminum chloride. Among these, polyaluminum chloride and aluminum sulfate are desirable. The release agent dispersion is used in the emulsion aggregation method, but the release agent dispersion may also be used when the toner is produced by suspension polymerization.

By the dispersion treatment, a release agent dispersion liquid containing release agent particles having a volume average particle diameter of 1 μm or less is obtained. In addition, the more preferable volume average particle diameter of the release agent particles is 100 nm or more and 500 nm or less.
When the volume average particle diameter is less than 100 nm, the properties of the binder resin used are affected, but generally the release agent component is hardly taken into the toner. On the other hand, if it exceeds 500 nm, the dispersion state of the release agent in the toner may be insufficient.

  For the preparation of the colorant dispersion, a known dispersion method can be used. For example, a general dispersion means such as a rotary shear type homogenizer, a ball mill having a medium, a sand mill, a dyno mill, or an optimizer can be employed. Is not to be done. The colorant is dispersed in water together with a polymer electrolyte such as an ionic surfactant, a polymer acid, or a polymer base. The volume average particle diameter of the dispersed colorant particles may be 1 μm or less, but if it is in the range of 80 nm or more and 500 nm or less, the dispersion of the colorant in the toner is preferable without impairing the cohesiveness.

(Aggregation process)
In the agglomeration step, a dispersion of resin particles, a colorant dispersion, a release agent dispersion, etc. are mixed to form a mixed solution, which is heated to agglomerate at a temperature lower than the glass transition temperature of the resin particles. Form. Aggregated particles are often formed by making the pH of the mixed solution acidic under stirring. The pH is preferably in the range of 2 to 7, and in this case, it is also effective to use a flocculant.
In the aggregation step, the release agent dispersion may be added and mixed at once with various dispersions such as a resin particle dispersion, or may be added in multiple portions.

  As the aggregating agent, a surfactant having a polarity opposite to that of the surfactant used for the dispersant, an inorganic metal salt, and a divalent or higher-valent metal complex are preferably used. In particular, the use of a metal complex is particularly desirable because the amount of the surfactant used can be reduced and the charging characteristics are improved.

As the inorganic metal salt, an aluminum salt and a polymer thereof are particularly suitable. In order to obtain a narrower particle size distribution, the valence of the inorganic metal salt is bivalent than monovalent, trivalent than bivalent, trivalent than trivalent, and tetravalent than trivalent. Inorganic metal salt polymers are more suitable.
In this embodiment, it is desirable to use a polymer of a tetravalent inorganic metal salt containing aluminum in order to obtain a narrow particle size distribution.

  Further, a toner having a structure in which the surface of the core aggregated particles is coated with a resin may be prepared by additionally adding a resin particle dispersion when the aggregated particles have a desired particle size (coating step). In this case, the release agent and the colorant are not easily exposed on the toner surface, which is desirable from the viewpoint of chargeability and developability. In the case of additional addition, a flocculant may be added or pH adjustment may be performed before additional addition.

(Fusion process)
In the fusion step, the agglomeration is stopped by raising the pH of the suspension of aggregated particles to a range of 3 to 9 under stirring conditions in accordance with the aggregation step, and the glass transition temperature of the resin is higher than the glass transition temperature. The aggregated particles are fused by heating at a temperature. Moreover, when it coat | covers with the said resin, this resin is also united and a core aggregated particle is coat | covered. The heating time may be performed to the extent that fusion is performed, and may be performed for about 0.5 hour to 10 hours.

Cool after fusion to obtain fused particles. Further, in the cooling step, crystallization may be promoted by reducing the cooling rate in the vicinity of the glass transition temperature (range of glass transition temperature ± 10 ° C.) of the resin, so-called slow cooling.
The fused particles obtained by fusing are made into toner particles through a solid-liquid separation process such as filtration and, if necessary, a washing process and a drying process.

(External addition process)
External toner additives such as fluidizing agents and auxiliaries are added to the obtained toner particles. As the external additive, the above-mentioned known particles are used.
These can be performed by, for example, a V-type blender, a Henschel mixer, a Redige mixer, or the like, and can be attached in stages. The toner of this embodiment can be obtained by externally adding the above components to the toner particles.

<Developer for electrostatic charge development>
The developer for electrostatic charge development of the present embodiment (hereinafter sometimes simply referred to as “developer”) is not particularly limited as long as it contains the toner of the present embodiment, and is a one-component developer or two-component developer. Any of the agents may be used. When used as a two-component developer, a toner and a carrier are mixed and used.
The carrier that can be used in the two-component developer is not particularly limited, and a known carrier is used. Examples thereof include magnetic metals such as iron oxide, nickel and cobalt, magnetic oxides such as ferrite and magnetite, resin-coated carriers having a resin coating layer on the surface of the core material, and magnetic dispersion carriers. Further, a resin-dispersed carrier in which a conductive material or the like is dispersed in a matrix resin may be used.

  Coating resins and matrix resins used for carriers include polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic. Examples include, but are not limited to, acid copolymers, straight silicone resins composed of organosiloxane bonds or modified products thereof, fluororesins, polyesters, polycarbonates, phenol resins, epoxy resins, and the like.

  Examples of the conductive material include metals such as gold, silver and copper, carbon black, titanium oxide, zinc oxide, barium sulfate, aluminum borate, potassium titanate, tin oxide, and carbon black, but are not limited thereto. It is not something.

Examples of the core material of the carrier include magnetic metals such as iron, nickel, and cobalt, magnetic oxides such as ferrite and magnetite, and glass beads. However, in order to use the carrier for the magnetic brush method, it is a magnetic material. May be.
The volume average particle size of the core material of the carrier is generally 10 μm or more and 500 μm or less, and may be 30 μm or more and 100 μm or less.

  In order to coat the surface of the core material of the carrier with a resin, there may be mentioned a method of coating with a coating layer forming solution in which the coating resin and, if necessary, various additives are dissolved in an appropriate solvent. The solvent is not particularly limited, and may be selected in consideration of the coating resin to be used, coating suitability, and the like.

  Specific resin coating methods include an immersion method in which the carrier core material is immersed in the coating layer forming solution, a spray method in which the coating layer forming solution is sprayed onto the surface of the carrier core material, and the carrier core material is fluidized air. And a kneader coater method in which the carrier core material and the coating layer forming solution are mixed in a kneader coater and the solvent is removed in a kneader coater.

  The mixing ratio (weight ratio) of the toner and the carrier in the two-component developer may be in the range of toner: carrier = 1: 100 to 30: 100, or in the range of 3: 100 to 20: 100. It may be.

<Image Forming Method and Image Forming Apparatus>
The image forming method of the present embodiment includes (a) a latent image forming step for forming an electrostatic charge image on the surface of the latent image holding member, and (b) an electrostatic charge image formed on the surface of the latent image holding member. A development step of developing with a developer to form a toner image, (c) a transfer step of transferring the toner image formed on the surface of the latent image holding member to the surface of the transfer target, and (d) the surface of the transfer target A fixing step of pressure-fixing the toner image transferred to the toner image at a maximum pressure of 1 MPa to 10 MPa.
The image forming apparatus according to the present embodiment also includes a latent image holding member, a latent image forming unit that forms an electrostatic charge image on the surface of the latent image holding member, and an electrostatic charge image formed on the surface of the latent image holding member. A developing means for developing a toner image by developing with a developer of a form, a transferring means for transferring the toner image formed on the surface of the latent image holding body to the surface of the transfer target, and the image transferred to the surface of the transfer target A fixing unit that pressurizes and fixes the toner image at a maximum pressure of 1 MPa to 10 MPa;

Each of the steps and means described above can be performed by known methods and means employed in conventional image forming methods and image forming apparatuses. In this embodiment, the transfer target is a final recording medium. When an intermediate transfer member is used, the toner image formed on the surface of the latent image holding member is temporarily transferred to the intermediate transfer member. After that, the toner image transferred to the transfer body and finally transferred onto the transfer body surface is fixed on the transfer body surface.
Further, the image forming method may include steps other than the above-described steps such as a cleaning step for cleaning the surface of the latent image holding member, and the image forming apparatus cleans the surface of the latent image holding member. It may include a cleaning means.

  When an electrophotographic photosensitive member is used as the latent image holding member, for example, image formation can be performed as follows. First, the surface of the electrophotographic photosensitive member is uniformly charged by a corotron charger, a contact charger or the like and then exposed to form an electrostatic charge image. Next, the toner particles are adhered to the electrostatic charge image by bringing the toner image into contact with or in proximity to a developing roll having a developer layer formed on the surface, thereby forming a toner image on the electrophotographic photosensitive member. The formed toner image is transferred onto the surface of a transfer medium such as paper using a corotron charger or the like. Further, the toner image transferred to the surface of the recording medium is fixed by a fixing device, and an image is formed on the recording medium.

  As the electrophotographic photoreceptor, generally, an inorganic photoreceptor such as amorphous silicon or selenium, an organic photoreceptor using polysilane, phthalocyanine or the like as a charge generation material or a charge transport material can be used. Therefore, an amorphous silicon photoreceptor is preferable.

<Fixing process and fixing means>
In the present embodiment, the fixing step is performed by applying pressure without heating. Further, the fixing unit does not have a heating unit.
The fixing pressure has a maximum pressure of 1 MPa or more and 10 MPa or less, more preferably 2 MPa or more and 8 MPa or less, and further preferably 3 MPa or more and 7 MPa or less.
A fixing pressure (fixing pressure) of 1 MPa or more is preferable because sufficient fixing properties can be obtained. Further, it is preferable that the pressure is 10 MPa or less because there is little occurrence of image contamination, fixing roll contamination, and paper wrapping due to occurrence of offset and the like, and the problem that the paper after fixing is bent (referred to as paper curl) hardly occurs.
As the fixing roll, a conventionally known fixing roll can be appropriately selected and used as long as the fixing pressure can be applied.
For example, a fixing roll in which a fluorine-based resin (for example, Teflon (registered trademark)), a silicone-based resin, perfluoroalkylate, etc. is coated on a cylindrical core metal can be exemplified, and in order to obtain a high fixing pressure, A fixing roll made of SUS can also be used. The fixing step is generally performed by passing a transfer medium between two rolls, but the two rolls can be formed of the same material or different materials. For example, combinations such as SUS / SUS, SUS / silicone resin, SUS / PFA, and PFA / PFA can be used.

  The pressure distribution between the fixing roll and the pressure roll can be measured by a commercially available pressure distribution measuring sensor, and specifically can be measured by a pressure measuring system between rollers manufactured by Iwata Industry Co., Ltd. In the present embodiment, the maximum pressure at the time of pressure fixing represents the maximum value in the change in pressure from the fixing nip entrance to the exit in the paper traveling direction.

In the present embodiment, the fixing step is performed without heating. Here, “fixing is performed without heating” means that no direct heating means to the fixing means is provided. Therefore, it does not prevent the temperature inside the machine from becoming higher than the environmental temperature due to heat generated by other power.
The fixing temperature is preferably 15 ° C. or higher and 50 ° C. or lower, more preferably 15 ° C. or higher and 45 ° C. or lower, and further preferably 15 ° C. or higher and 40 ° C. or lower.
It is preferable that the fixing temperature be within the above range because good fixing properties can be obtained.

<Cleaning process and cleaning means>
The image forming method of the present embodiment may further include a cleaning process for cleaning toner remaining on the surface of the latent image holding member after the transfer process, and the cleaning process may be a brush cleaning process for cleaning residual toner with a brush. preferable. In addition, the image forming apparatus of the present embodiment preferably includes a cleaning unit, and the cleaning unit is more preferably a brush cleaning unit.
A brush cleaning system with less stress on individual toners is suitable for cleaning the transfer residual toner on the photoreceptor. As an auxiliary, an elastic blade with the pressing pressure lowered may be used, but it is preferable that the main cleaning is performed by a brush.

In general, cleaning of toner remaining on the surface of the latent image holding member is performed by a cleaning blade or a cleaning brush. In this embodiment, it is preferable to clean the residual toner with a cleaning brush.
The brush cleaning process is preferable because the pressure applied to the residual toner is small and adhesion to the photoconductor does not occur. On the other hand, in the case of blade cleaning, residual toner may flow due to the stress from the cleaning blade and adhere to the photoreceptor, and filming or the like may occur.

The brush cleaning means used in the present embodiment is a toner removing member having a brush member, and takes a form according to the purpose, such as a fixed brush such as a brush, or a rotating brush used by rotating fibers arranged in a cylindrical shape. be able to. In addition, a conductive brush used by applying a voltage using conductive fibers can also be used.
Brush fibers include natural cellulose fibers, regenerated cellulose fibers such as rayon, nylon fibers, polypropylene fibers, polyester fibers, polyurethane fibers, polyolefin fibers, acrylic fibers, polyamide fibers, polyamideimide fibers, polyetheramide fibers, polyphenylene sulfide fibers, Examples thereof include polybenzimidazole fiber and polyvinyl fiber, but are not limited thereto.

  In order to impart conductivity, these fibers may be mixed with carbon black, metal oxide powder, metal powder, conductive resin, or the like. The brush of the toner removing member may be provided with a toner scraping member as necessary, and one or a plurality of toner removing members may be provided for each latent image holding member as required. As a particularly preferable form, a toner removing member in which conductive fibers are arranged in a cylindrical shape is installed adjacent to the latent image holding member, and a flicker bar for blowing toner off the brush fibers is installed adjacent to the toner removing member. An example is a form in which a toner collection container for containing the blown toner is provided.

FIG. 2 is a cross-sectional view schematically showing a basic configuration of a preferred embodiment of an image forming apparatus capable of performing the image forming method of the present embodiment. An image forming apparatus 100 shown in FIG. 2 includes an electrophotographic photosensitive member (latent image holding member) 107, a charging device 108 such as corotron or scorotron for charging the electrophotographic photosensitive member 107, and a power source 109 connected to the charging device 108. An exposure device (latent image forming means) 110 for exposing the electrophotographic photosensitive member 107 charged by the charging device 108 to form an electrostatic image, and developing the electrostatic image formed by the exposure device 110 with a developer. Then, a developing device (developing unit) 111 that forms a toner image, a transfer device (transfer unit) 112 that transfers the toner image formed by the developing device 111 to the transfer target 500, and the electrophotographic photosensitive member 107 after transfer A cleaning device 113 that removes residual toner, a static eliminator 114, and a fixing device (fixing means) 115 are provided.
Here, in FIG. 2, a cleaning device 113 is a brush cleaning device, and removes toner remaining on the electrophotographic photosensitive member 107 by a brush member. The fixing device 115 is a pressure fixing device and does not have a heating unit.

As each device in the image forming apparatus 100, any of those employed in a conventional image forming apparatus can be applied.
In the present embodiment, an image forming apparatus in which the static eliminator 114 is not provided may be used. In FIG. 2, the charging device 108 is a contact-type charging device, but may be a non-contact type charging device such as a corotron charger.

(Transfer material)
In the present embodiment, any material may be used as the transfer target. In the present embodiment, it is preferable to use a transfer sheet having a texture index of 20 or more as the transfer target. The formation index is more preferably 23 or more, and further preferably 25 or more.
For paper, it is important to reduce the unevenness of the ground in order to achieve uniform fixing of the in-paper image. By reducing the unevenness of the texture, the pressure distribution when the toner is pressure-fixed to the paper is reduced, and even with a small-diameter toner, uniform fixing is possible, and it is possible to achieve both image quality and pressure fixability. Become.
A transfer paper having a texture index of 20 or more is preferable because the texture unevenness is small, so that both image quality and pressure fixability can be achieved.

Here, the texture index is measured by the following method.
M / K Systems, Inc. A 3D sheet analyzer (M / K950) manufactured by (MKS) was used, the aperture of the analyzer was 1.5 mm in diameter, and measurement was performed using a micro formation tester (MFT). That is, a sample is mounted on a rotating drum in a 3D sheet analyzer, and a local basis weight difference in the sample is calculated by a light source mounted on the drum shaft and a photodetector mounted on the outside of the drum corresponding to the light source. Measure as light intensity difference. The measurement target range at this time is set by the diameter of the diaphragm attached to the light incident part of the photodetector. Next, the light intensity difference (deviation) is amplified, A / D converted, classified into 64 photometric basis weight classes, 1000000 data are taken in one scan, and the histogram frequency for the data is obtained. obtain. Then, the highest frequency (peak value) of the histogram is divided by the number of classes having a frequency of 100 or more out of those classified into classes corresponding to a micro basis weight of 64, and the value obtained by dividing it by 1/100 is the ground index. Calculated. The formation index FI is expressed by the following formula.
FI = ((peak value (frequency)) / (number of classes of 100 degrees or more)) × (1/100)
The texture index of the transfer paper indicates that the larger the value, the less the paper quality is uneven and the texture is better.

  In order to reduce the unevenness of the transfer paper, which is the fixing medium, a base paper screen or vortex cleaner is installed just in front of the head box of the paper machine so that the flow direction of the raw material is not constant, guar gum, Locust bean gum, mannogalactan, deacetylated karaya gum, alginate, carboxymethylcellulose, methylcellulose, hydroxyethylcellulose, etc. It is not something.

  The unevenness of formation can also be reduced by providing a coating layer on the base paper. The coating layer in the coated paper is formed to increase the smoothness, uniformity, opacity and whiteness of the transfer paper, reinforce the strength, and improve the image forming suitability of the transfer paper. The coating layer is mainly composed of a pigment, a pigment dispersant, a binder resin, and the like. As the pigment, kaolin clay, delaminated clay, Georgia clay, China clay, calcium carbonate, satin white, titanium oxide, aluminum hydroxide and the like are used. As the pigment dispersant, sodium pyrophosphate, sodium polyacrylate, sodium hexametaphosphate, sodium tripolyphosphate, sodium styrene-maleic acid copolymer, and the like are used. As the binder resin, polyvinyl alcohol, carboxymethyl cellulose, styrene butadiene latex, various starches, casein, soy protein, vinyl acetate latex, vinyl acetate-dibutyl maleate copolymer, and the like are used.

These coatings are applied to transfer paper using a roll coater, air knife coater, rod coater, cast coater, etc. after dispersion, dissolution and preparation of pigments and binders, infrared dryers, drum dryers, air cap dryers, It is dried by an air foil dryer or an air conditioner bare dryer.
The average mass ratio is around 25% pigment and 5% binder resin with respect to 70% of the base paper.

  The transfer paper used in the image forming method of the present embodiment is usually formed using wood pulp as a main raw material, and a filler is blended in the transfer paper. The filler used here is a white filler such as heavy or light calcium carbonate, talc, kaolin, clay, titanium dioxide, zeolite, white carbon, among others, since the coloring property of the coloring material is good, calcium carbonate. Is preferred. The filler is preferably blended in the range of 5% by mass to 30% by mass, more preferably 10% by mass to 25% by mass in order to increase the gap of the transfer paper and improve the opacity. A blending amount of 30% by mass or less is preferable because the transfer paper has high strength and hardly generates paper dust.

  Hereinafter, although an Example and a comparative example are given and this embodiment is described in detail in detail, this embodiment is not limited to the following examples. Unless otherwise specified, “part” and “%” are based on mass.

<Synthesis of 2-methyl-2- [N- (tert-butyl) -N- (1-diethoxyphosphoryl-2,2-dimethylpropyl) -aminoxy] -propionic acid (MBPAP)>
In a nitrogen purged glass vessel with a reflux condenser, 500 parts degassed toluene, 35.9 parts CuBr, 15.9 parts copper powder, 86.7 parts N, N, N ′, N ′, N ”-Pentamethyldiethylenetriamine was introduced and with stirring, 580 parts degassed toluene, 42.1 parts 2-bromo-2-methylpropionic acid and 78.9 parts N-tert-butyl-N— ( 1-Diethylphosphono-2,2-dimethylpropyl) nitroxide was introduced and stirred for 90 minutes at room temperature, after which the reaction medium was filtered and the toluene filtrate was washed twice with a saturated aqueous NH ₄ Cl solution. The obtained solid was washed with pentane, vacuum-dried, and 2-methyl-2- [N- (tert-butyl) -N- (1-diethoxyphosphoryl-2,2-dimethylpropyl) -aminoxy] -propyl. It was obtained acid (MBPAP).
The molar mass of the prepared MBPAP determined by mass spectrometry was 381.44 g / mol (C ₁₇ H ₃₆ NO ₆ P), which was confirmed to be the target product.

<Synthesis of divinyl adipate-MBPAP adduct (DABA)>
126 parts of MBPAP synthesized above, 28.5 parts of divinyl adipate, and 230 parts of toluene were introduced into a glass vessel with a reflux condenser tube purged with nitrogen, and the reaction was allowed to proceed at 80 ° C. for 4 hours, followed by cooling to room temperature and divinyl adipate-MBPAP. An active living dormant for triblock polymerization was prepared by adjusting adduct (DABA) and capping both ends with nitroxide groups.

<Preparation of release agent particle dispersion>
Ester wax (manufactured by NOF Corporation: WE-2, melting point 65 ° C.): 50 parts Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK): 5 parts Ion exchange water: 200 The above components were mixed, heated to 95 ° C., dispersed using a homogenizer (manufactured by IKA: Ultra Tarrax T50), then dispersed with a Manton Gorin high-pressure homogenizer (manufactured by Gorin), and an average particle size of 230 nm. A release agent particle dispersion liquid (release agent concentration: 20%) prepared by dispersing the release agent was prepared.

<Preparation of colorant particle dispersion>
Cyan pigment (Daiichi Seika Kogyo Co., Ltd., Pigment Blue 15: 3 (copper phthalocyanine)): 1,000 parts Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen R): 150 parts Ion-exchanged water: 9,000 parts or more are mixed, dissolved, and dispersed for about 1 hour using a high-pressure impact disperser Ultimateizer (manufactured by Sugino Machine Co., Ltd., HJP30006) to disperse the colorant (cyan pigment). A colorant particle dispersion was prepared. The average particle diameter of the colorant (cyan pigment) in the colorant particle dispersion was 0.15 μm, and the colorant particle concentration was 23%.

(Synthesis of ABA type triblock copolymer 1)
Add 33.8 parts of butyl acrylate monomer and 1.55 parts of the above DABA toluene solution to a glass container equipped with a reflux condenser, a nitrogen inlet pipe, and a stirrer, and mix well at 80 ° C. under a nitrogen stream. The temperature was raised and the butyl acrylate monomer was polymerized for 8 hours (Block B). When the molecular weight was measured by GPC as needed, the number average molecular weight was 53378, which was within 5% of the theoretical value of 52000, indicating good living controllability.

  Thereafter, after the temperature was lowered to 80 ° C., 66.2 parts of a styrene / acrylic acid monomer mixture (97 parts by weight of styrene, 3 parts of acrylic acid) was dropped, and the temperature was raised again to 110 ° C., and the polymerization was further continued for 8 hours. Continued chain extension (Block A). When the molecular weight of the polymer was measured, the total number average molecular weight was 158000, and the total number average molecular weight derived from the block A which is a styrene / acrylic acid copolymer obtained by subtracting the molecular weight of the block B was 104622, and the theoretical values 101970 and 5 %, With good chain extension. In this case, since the chain A is chain-extended from both ends of the block B, the total number average molecular weight is the total molecular weight of 2 units of the A block, and the number average molecular weight per A block is 52311. . Further, the ratio (A / B) of the number average molecular weight of the A block and the B block was 1.96.

The above polymer is dissolved in 225 parts of THF, taken out, dropped into methanol to reprecipitate the block copolymer, the precipitate is filtered, and further washed with methanol, followed by vacuum drying at 40 ° C. The triblock copolymer 1 was obtained.
When the triblock copolymer 1 after drying was subjected to DSC measurement, Tg derived from the A block was 103 ° C., and Tg derived from the B block was −55 ° C.

(Synthesis of ABA type triblock copolymer 2)
Triblock Copolymer 2 was the same as Triblock Copolymer 1 except that 53.8 parts of butyl acrylate monomer, 1.84 parts of DABA toluene solution, and 46.2 parts of styrene / acrylic acid monomer mixture were used. Was polymerized. The obtained total number average molecular weight was 131400 (theoretical value 130000), A block number average molecular weight 60755 (theoretical value 60108), B block number average molecular weight 70645 (theoretical value 69892), and A / B 0.86.
Furthermore, the Tg derived from the A block was 103 ° C., and the Tg derived from the B block was −55 ° C.

(Synthesis of ABA type triblock copolymer 3)
The triblock copolymer was the same as the triblock copolymer 1 except that the butyl acrylate monomer was changed to 20 parts of 2-ethylhexyl acrylate, the DABA toluene solution to 1.59 parts, and the styrene / acrylic acid monomer mixture to 80 parts. 3 was polymerized. The obtained total number average molecular weight was 153000 (theoretical value 150,000), A block number average molecular weight 122400 (theoretical value 120,000), B block number average molecular weight 30600 (theoretical value 30000), and A / B 4.0.
Furthermore, Tg derived from the A block was 103 ° C., and Tg derived from the B block was −70 ° C.

(Synthesis of ABA type triblock copolymer 4)
A triblock copolymer 1 was prepared except that the butyl acrylate monomer was changed to 27.3 parts of 2-ethylhexyl acrylate, the DABA toluene solution was changed to 4.35 parts, and the styrene / acrylic acid monomer mixture was changed to 72.8 parts. Block copolymer 4 was polymerized. The obtained total number average molecular weight was 56500 (theoretical value 55000), A block number average molecular weight 41105 (theoretical value 40014), B block number average molecular weight 15395 (theoretical value 14986), and A / B 2.67.
Furthermore, Tg derived from the A block was 103 ° C., and Tg derived from the B block was −70 ° C.

(Synthesis of ABA type triblock copolymer 5)
The triblock copolymer is the same as the triblock copolymer 1 except that the butyl acrylate monomer is changed to 33.3 parts, the DABA toluene solution is changed to 0.53 parts, and the styrene / acrylic acid monomer mixture is changed to 66.7 parts. Polymer 5 was polymerized. The total number average molecular weight obtained was 453500 (theoretical value 450,000), A block number average molecular weight 302333 (theoretical value 300000), B block number average molecular weight 151167 (theoretical value 150,000), and A / B 2.0.
Furthermore, the Tg derived from the A block was 103 ° C., and the Tg derived from the B block was −20 ° C.

(Synthesis of ABA type triblock copolymer 6)
22.5 parts of stearyl acrylate monomer / behenyl acrylate monomer mixture (20 parts of stearyl acrylate monomer, 80 parts of behenyl acrylate monomer), 1.03 parts of DABA toluene solution, 77.6 parts of styrene / acrylic acid monomer mixture The triblock copolymer 6 was polymerized in the same manner as the triblock copolymer 1 except that it was changed to. The obtained total number average molecular weight was 233000 (theoretical value 232000), A block number average molecular weight 180758 (theoretical value 179882), B block number average molecular weight 52242 (theoretical value 52018), and A / B 3.46.
Furthermore, Tg derived from the A block was 103 ° C., and Tg derived from the B block was −70 ° C.

[Example 1]
(Manufacture of toner 1)
After kneading 100 parts of the ABA type triblock copolymer 1 prepared above and 50 parts of paraffinic process oil (Diana Process Oil PW90) at 155 ° C. in a bench kneader (Irie Shokai PBV-01), kneading. To 400 parts of the resin, 8.0 parts of sorbitan sesquiolate and 120 parts of methyl ethyl ketone (MEK) in which 0.8 parts of sodium dodecylbenzenesulfonate are dissolved are added, and a reflux condenser, a stirrer, an ion-exchanged water dropping device, and a heating device are attached. Then, the mixture was thoroughly mixed at 65 ° C. Then, after heat-mixing at 65 degreeC for 1 hour, 1,000 parts ion-exchange water was dripped at the speed | rate of 1 g / min, and the phase inversion emulsification of the block copolymer resin (1) was performed. Further, the phase-inverted emulsion was cooled and MEK was removed from the emulsion under reduced pressure at 60 ° C. using an evaporator to obtain a resin particle dispersion (1).
The volume average particle diameter of the resin particles in the obtained resin particle dispersion (1) was 320 nm, and the solid content concentration was 42.5%.

<Manufacture of toner particles (1)>
Resin particle dispersion (1): 565 parts (240 parts solid content)
Colorant particle dispersion: 22.87 parts (solid content 5.3 parts)
Release agent particle dispersion: 50 parts (solid content 10 parts)
Among the raw materials, 158 parts (67 parts solids) of the resin particle dispersion (1) were left, and the raw materials were placed in a cylindrical stainless steel container and dispersed and mixed for 30 minutes while applying a shearing force at 8,000 rpm with Ultraturrax. Then, 0.14 part of a 10% nitric acid aqueous solution of polyaluminum chloride was added dropwise as a flocculant. At this time, the pH of the raw material dispersion was controlled in the range of 4.2 to 4.5. The pH was adjusted with 0.3N nitric acid or 1N aqueous sodium hydroxide as required. Thereafter, the raw material dispersion is transferred to a polymerization kettle equipped with a stirrer and a thermometer and heated to promote the growth of adhered aggregated particles at 40 ° C. When the volume average particle diameter reaches 5.0 μm, 158 parts of the separated resin particle dispersion (1) was gradually added afterwards, the temperature was raised to 50 ° C., and the particle diameter was adjusted to 6.1 μm. Further, after raising the pH to 7.5, the temperature was raised to 98 ° C. and held at 98 ° C. for 6 hours, and then the pH was gradually lowered to 6.5, then the heating was stopped and the mixture was allowed to cool. Thereafter, it was sieved with a 45 μm mesh, washed repeatedly with water and then dried with a freeze dryer to obtain toner particles (1).
As a result of measuring the particle size distribution of the final toner particles using a Coulter counter, the volume average particle size was 6.0 μm and the volume average particle size distribution was 1.22.
For the measured particle size distribution of the final toner particles, a cumulative distribution is drawn from the smaller diameter side with respect to the divided particle size range (channel), and the particle size at which the accumulation becomes 16% is defined as the volume average particle size. The particle diameter is defined as D16v, and the cumulative particle size of 50% is defined as the volume average particle diameter D50v. In accordance with this, the particle diameter that is 84% cumulative is defined as the volume average particle diameter D84v. At this time, the volume average particle size distribution (GSDv) is defined as (D84v / D16v) ^1/2 .

  This toner particle (1) was treated with 0.5% of hexamethyldisilazane-treated silica (average particle size 40 nm) as an external additive, and a titanium compound obtained by baking after treatment with 50% isobutyltrimethoxysilane in metatitanic acid ( Add 0.7% (average particle size 30 nm) (both mass ratio to toner particles), mix for 10 minutes with 75 L Henschel mixer, and then sieve with wind sieving machine Hivolta 300 (manufactured by Shin Tokyo Kikai Co., Ltd.). A toner (1) was prepared.

(Preparation of developer (1))
0.15 parts of polyvinylidene fluoride resin and 1.35 parts of a copolymer of methyl methacrylate and trifluoroethylene (polymerization ratio (mass basis)) with respect to 100 parts of ferrite core having a volume average particle diameter of 50 μm 80:20) A ferrite core was coated with a resin using a kneader apparatus to prepare a carrier. The obtained carrier and toner (1) were mixed in a ratio of 100 parts: 8 parts by a 2 liter V blender to prepare developer (1).

(Evaluation)
Using the developer (1), toner was evaluated using a DocuPrint C2425 remodeling machine manufactured by Fuji Xerox Co., Ltd. This printer uses a brush cleaner for cleaning the transfer residual toner on the photoconductor.
As for the fixing device, a two-roll type fixing device capable of adjusting the maximum fixing pressure was modified, and the image-side pressure roll was changed to a high-hardness roll in which a SUS tube was coated with Teflon (registered trademark). Further, plain paper (C2 paper manufactured by Fuji Xerox Co., Ltd.) was used as the transfer target. Fixing conditions were as shown in Table 1.
The following evaluation was performed on the fixed image. The obtained results are shown in Table 1.

-Fixed gloss unevenness-
Using a solid image (5 cm × 5 cm) adjusted to an area ratio of 95%, the uniformity of the image gloss after fixing was visually observed, and the following evaluation was performed.
<Evaluation criteria>
○: Level with no problem in practical use even though uniform gloss or slight unevenness is observed as a whole ×: Level with problem in practical use due to unevenness in image gloss

-Tape peeling-
Using a cellophane tape (“CT24”, manufactured by Nichiban Co., Ltd.) using a solid image (5 cm × 5 cm) adjusted to an area ratio of 95%, the image was peeled after closely contacting the image part with the belly of the finger. Thereafter, the presence or absence of image transfer was visually observed on the adhesive surface of the peeled tape, and the following evaluation was performed.
<Evaluation criteria>
○: Level of image transfer to the adhesive surface of the tape is not recognized, or slight transfer is observed, but there is no practical problem ×: Level of image transfer to the adhesive surface of the tape is practically problematic

-Image scratch-
A pencil scratch test based on JIS K5400 was conducted, and the following determination was made based on the pencil hardness.
<Evaluation criteria>
○: Level at which the brush hardness is H or higher and no problem at all ×: Level at which the pencil hardness is lower than H is practically problematic

[Example 2]
As in Example 1, 100 parts of ABA type triblock copolymer 2 was used instead of ABA type triblock copolymer 1, and 30 parts of paraffinic process oil (Diana process oil PW90) was used as a process oil component. Thus, a resin particle dispersion (2) was obtained. The volume average particle diameter of the resin particles in the obtained resin particle dispersion (2) was 298 nm, and the solid content concentration was 42.3%.

<Production of toner particles (2)>
As in Example 1, toner particle (2) was obtained by using resin particle dispersion (2) instead of resin particle dispersion (1). The volume average particle size was 6.1 μm, and the volume average particle size distribution was 1.25.
Further, a toner (2) was prepared in the same manner as in Example 1 except that the toner particles (1) were changed to toner particles (2), and the toner (1) was replaced with the toner (2) in the same manner as in Example 1. Thus, developer (2) was produced.
Evaluation was conducted in the same manner as in Example 1 using the developer (2) obtained. The obtained results are shown in Table 1.

[Example 3]
As in Example 1, 100 parts of ABA type triblock copolymer 3 instead of ABA type triblock copolymer 1, paraffinic process oil (Diana process oil PW90) and naphthenic process oil as process oil components A resin particle dispersion (3) was obtained using 10 parts of a mixture of Diana process oil NP23 (80 parts of PW90, 20 parts of NP23). The volume average diameter of the resin particles in the obtained resin particle dispersion (3) was 328 nm, and the solid content concentration was 42.3%.

<Manufacture of toner particles (3)>
As in Example 1, toner particle (3) was obtained by using resin particle dispersion (3) instead of resin particle dispersion (1). The volume average particle size was 6.2 μm and the volume average particle size distribution was 1.23.
Further, a toner (3) was prepared in the same manner as in Example 1 except that the toner particles (1) were changed to toner particles (3), and the toner (1) was replaced with the toner (3) in the same manner as in Example 1. Thus, developer (3) was produced.
Evaluation was conducted in the same manner as in Example 1 using the developer (3) thus obtained. The obtained results are shown in Table 1.

[Example 4]
As in Example 1, 100 parts of ABA type triblock copolymer 4 was used instead of ABA type triblock copolymer 1, and 5 parts of paraffinic process oil (Diana process oil PW90) was used as the process oil component. Thus, a resin particle dispersion (4) was obtained. The volume average diameter of the resin particles in the obtained resin particle dispersion (4) was 354 nm, and the solid content concentration was 42.5%.

<Production of toner particles (4)>
As in Example 1, toner particle (4) was obtained by using resin particle dispersion (4) instead of resin particle dispersion (1). The volume average particle size was 6.5 μm, and the volume average particle size distribution was 1.25.
Further, a toner (4) was prepared in the same manner as in Example 1 except that the toner particles (1) were changed to toner particles (4), and the toner (1) was replaced with the toner (4) in the same manner as in Example 1. Developer (4) was prepared.
Evaluation was conducted in the same manner as in Example 1 using the developer (4) thus obtained. The obtained results are shown in Table 1.

[Example 5]
As in Example 1, 100 parts of ABA type triblock copolymer 5 was used instead of ABA type triblock copolymer 1, and 50 parts of paraffinic process oil (Diana process oil PW90) was used as the process oil component. Thus, a resin particle dispersion (5) was obtained. The volume average diameter of the resin particles in the obtained resin particle dispersion (5) was 288 nm, and the solid content concentration was 42.3%.

<Manufacture of toner particles (5)>
As in Example 1, toner particle (5) was obtained by using resin particle dispersion (5) instead of resin particle dispersion (1). The volume average particle size was 6.2 μm and the volume average particle size distribution was 1.25.
Further, a toner (5) was prepared in the same manner as in Example 1 except that the toner particles (1) were changed to toner particles (5), and the toner (1) was replaced with the toner (5) in the same manner as in Example 1. Developer (5) was prepared.
Evaluation was conducted in the same manner as in Example 1 using the developer (5) thus obtained. The obtained results are shown in Table 1.

[Example 6]
As in Example 1, 100 parts of ABA type triblock copolymer 6 was used instead of ABA type triblock copolymer 1, and 50 parts of paraffinic process oil (Diana process oil PW90) was used as a process oil component. Thus, a resin particle dispersion (6) was obtained. The volume average diameter of the resin particles in the obtained resin particle dispersion (6) was 274 nm, and the solid content concentration was 42.4%.

<Manufacture of toner particles (6)>
As in Example 1, toner particle (6) was obtained by using resin particle dispersion (6) instead of resin particle dispersion (1). The volume average particle size was 6.3 μm and the volume average particle size distribution was 1.23.
Further, a toner (6) was prepared in the same manner as in Example 1 except that the toner particles (1) were changed to toner particles (6), and the toner (1) was replaced with the toner (6) in the same manner as in Example 1. Developer (6) was prepared.
Evaluation was conducted in the same manner as in Example 1 using the developer (6) thus obtained. The obtained results are shown in Table 1.

[Comparative Example 1]
100 parts of oxidized polyethylene (average molecular weight 4000, acid value 20 mgKOH / g) and 50 parts of magnetite (EPT1000 manufactured by Toda Kogyo) were melt-mixed at 140 ° C. and then pulverized by a pulverizer to obtain a powder having a volume average particle diameter of 10.5 μm. Obtained. This powder was dispersed in a mixed solution of kaolin (H kaolin, manufactured by Tsuchiya Kaolin) 2.5 parts, styrene butadiene copolymer (butadiene content 15%, 4544 manufactured by Denki Kagaku Kogyo), and xylene 250 parts, Drying was performed with a spray dryer (inlet temperature 150 ° C., outlet temperature 100 ° C.) to prepare a toner (7) having a volume average particle diameter of 13.0 μm. The obtained toner (7) was mixed with a carrier in the same manner as in Example 1 to prepare a developer (7).
Evaluation was conducted in the same manner as in Example 1 using the developer (7) thus obtained. The obtained results are shown in Table 1.

[Comparative Example 2]
In the same manner as in Example 1, 100 parts of ABA type triblock copolymer 1 was used, and a resin oil dispersion (8) was obtained without using the process oil component (excluding the bench kneader process). The volume average diameter of the resin particles in the obtained resin particle dispersion (8) was 450 nm, and the solid content concentration was 44.3%.

<Manufacture of toner particles (8)>
As in Example 1, toner particle (8) was obtained by using resin particle dispersion (8) instead of resin particle dispersion (1). The volume average particle size was 6.8 μm, and the volume average particle size distribution was 1.30.
Further, a toner (8) was prepared in the same manner as in Example 1 except that the toner particles (1) were changed to toner particles (8), and the toner (1) was replaced with the toner (8) in the same manner as in Example 1. Developer (8) was produced.
Evaluation was conducted in the same manner as in Example 1 using the developer (8) thus obtained. The obtained results are shown in Table 1.

100 Image forming apparatus 107 Electrophotographic photosensitive member (image holding member)
108 Charging Device 109 Power Supply 110 Exposure Device (Latent Image Forming Unit)
111 Developing device (developing means)
112 Transfer device (transfer means)
113 Cleaning device 114 Static eliminator 115 Fixing device (fixing means)
500 Transcript

Claims (6)

  A block having a polymer structure containing a repeating unit derived from a styrene-based monomer and a B block having a polymer structure having a glass transition temperature (Tg) of −10 ° C. or lower and a number average molecular weight of 50,000 to 500,000 An electrostatic charge developing toner comprising: an ABA triblock copolymer; and at least one selected from the group consisting of paraffinic oils, naphthenic oils and aromatic oils.   The electrostatic charge developing toner according to claim 1, wherein the B block has a polymer structure containing a repeating unit derived from a (meth) acrylic monomer.   The glass transition temperature Tg (A) of the A block and the glass transition temperature Tg (B) of the B block satisfy a relationship of Tg (A) ≧ Tg (B) + 80 ° C. 3. Toner for electrostatic charge development.   The ratio A / B between the number average molecular weight A of the A block and the number average molecular weight B of the B block contained in the ABA type triblock copolymer is 0.4 or more and 4 or less. 4. The electrostatic charge developing toner according to any one of 3 above.   An electrostatic charge developing developer comprising the electrostatic charge developing toner according to claim 1. A latent image forming step of forming an electrostatic charge image on the surface of the latent image carrier;
A developing step of developing the electrostatic image formed on the surface of the latent image holding member with the electrostatic charge developing developer according to claim 5 to form a toner image;
A transfer step of transferring the toner image formed on the surface of the latent image carrier to the surface of the transfer target;
And a fixing step of pressure-fixing the toner image transferred to the surface of the transfer medium with a maximum pressure of 1 MPa or more and 10 MPa or less.