JP2008122560A - Toner for electrostatic charge image development and method for manufacturing same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner for electrostatic charge image development and a method for manufacturing the toner by which both of low temperature fixing property and heat-resistant storage property (free from image defects such as hollow transfer, halftone irregularity and stripe defects) are made compatible and odor is not caused. <P>SOLUTION: The toner for electrostatic charge image development contains a resin prepared by copolymerizing a polymerizable monomer containing a compound expressed by general formula (1):H<SB>2</SB>C=CH-COOR, characterized in that: the composition ratio of the compound expressed by general formula (1) to the resin is 20 to 45 mass%; the volatilized amount of the compound expressed by general formula (1) is 5 ppm or less with respect to the toner for electrostatic charge image development; and the glass transition temperature of the toner is 20 to 40°C. In formula (1), R represents a 3-12C alkyl group. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrostatic charge image developing toner and a method for producing the same, and more particularly to an electrostatic charge image developing toner having a multilayer structure and a method for producing the same.

  In recent years, vigorous research has been carried out to reduce power consumption when a printer or a copier is moving. In addition, with the increasing use of printers in offices due to the penetration of the Internet environment and the expansion of usage opportunities in various forms of offices and homes due to the trend of the times such as home use of digital devices such as printers and facsimiles Reducing low-grade power and power costs is an inevitable issue. Therefore, printers and copiers are required to achieve low temperature fixing by reducing the heat and energy required for fixing to achieve the problem. As an example, a technique has been developed that can form a fixed image at a lower temperature than conventional ones using toner containing a low melting point wax (see, for example, Patent Document 1).

On the other hand, toners that can be fixed at low temperatures tend to have difficulties in thermal stability, causing image defects (transfer omission, halftone unevenness, streak failure), and blocks where toners stick to each other during storage or transportation. Phenomenon such as crystallization occurred.
JP 2001-42564 A

  In order to lower the glass transition point so that the toner melts at a low temperature, it is necessary to increase the amount of the polymerizable monomer (monomer) having a low polymer glass transition point represented by the general formula (1). Since such a monomer has low polymerization reactivity, it tends to remain as an unreacted monomer during polymerization. As a result, the residual monomer acts as a plasticizer, which may cause a problem in heat-resistant storage stability, or may cause toner agglomerates and cause image defects. In addition, if a material having a wide molecular weight distribution is used, it may be difficult to partially melt and cause fixing failure.

  The present invention has been made in view of the above problems, and an object of the present invention is to achieve both low-temperature fixability and heat-resistant storage stability (no image defects such as transfer loss, halftone unevenness, streak failure, etc.) and odor. It is an object to provide a toner for developing an electrostatic charge image that does not generate toner and a method for producing the same.

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

  1. In the toner for developing an electrostatic image containing a resin obtained by copolymerizing a polymerizable monomer containing a compound represented by the following general formula (1), the composition of the compound represented by the general formula (1) with respect to the resin The ratio is 20 to 45% by mass, the volatilization amount of the compound represented by the general formula (1) is 5 ppm or less with respect to the electrostatic image developing toner, and the glass transition point is 20 to 40 ° C. A toner for developing an electrostatic charge image.

Formula _{(1) H 2 C = CH} -COOR
(In the formula, R represents an alkyl group having 3 to 12 carbon atoms.)
2. 2. The toner for developing an electrostatic charge image according to 1 above, wherein the resin has a weight average molecular weight (Mw) of 10,000 to 50,000, a number average molecular weight (Mn) of 5,000 to 25,000, and Mw / Mn of 2 to 4. .

  3. For electrostatic image development, comprising the steps of copolymerizing a polymerizable monomer containing a compound represented by the following general formula (1) to polymerize resin particles, and aggregating and fusing the resin particles and colorant particles In the toner production method, in the polymerization step, the polymerization reaction is performed n times (where n is 2 or more), and the polymerization initiator is added in two portions. 30% by mass or more of the polymerization initiator amount is charged, and when the polymerization rate of the n-th polymerization reaction becomes 90% or more, the remaining polymerization initiator amount is charged. Toner manufacturing method.

Formula _{(1) H 2 C = CH} -COOR
(In the formula, R represents an alkyl group having 3 to 12 carbon atoms.)

  The present invention provides a toner for developing an electrostatic charge image that has both low-temperature fixability and heat-resistant storage stability (no image defects such as omission of transfer, halftone unevenness, streak failure, etc.) and no odor, and a method for producing the same. be able to.

  As a result of intensive studies, the present inventors have found that in the electrostatic charge image developing toner containing a resin obtained by copolymerizing a polymerizable monomer containing the compound represented by the general formula (1), the general formula (1) The composition ratio of the compound represented by) to the resin is 20 to 45% by mass, and the volatilization amount of the compound represented by the general formula (1) is 5 ppm or less with respect to the electrostatic image developing toner. In addition, the electrostatic charge image developing toner having a glass transition point of 20 to 40 ° C. achieves both low-temperature fixability and heat-resistant storage stability (no image defects such as transfer omission, halftone unevenness, streak failure, etc.) It has been found that an electrostatic charge image developing toner that does not generate odor can be obtained.

  Hereinafter, the present invention will be described in detail.

[Technical idea of the present invention]
In order to obtain an electrostatic charge image developing toner (hereinafter also referred to as toner) having low temperature fixability, it is necessary to lower the glass transition point (hereinafter also referred to as Tg) of the toner. For this purpose, a large amount of a polymerizable monomer having a low Tg as represented by the general formula (1) must be used.

  However, since the polymerizable monomer represented by the general formula (1) has a lower polymerization reactivity than styrene, it tends to remain as an unreacted monomer during polymerization. Furthermore, the polymerizable monomer represented by the general formula (1) has a strong odor and a high odor. In addition, toner odor is generated by heating at the time of fixing, and a plasticizer effect is brought about on the toner. The plasticizer effect referred to here is advantageous for low-temperature fixability because the toner melts at a lower temperature, but from the viewpoint of heat-resistant storage stability of the toner, the toner tends to agglomerate and the temperature becomes lower. It is necessary to store in In addition, toner agglomerates may result in image defects. By setting the polymerizable monomer having a low Tg as represented by the general formula (1) to 5 ppm or less with respect to the toner, it is possible to achieve both of them.

  In order to obtain such a toner, for example, when the polymerization reaction is performed in multiple stages, the polymerization initiator added in the initial stage of polymerization is consumed in the multiple stage reaction, and the polymerization rate during the final polymerization reaction is 90%. In this case, by adding the polymerization initiator again, it becomes possible to proceed the polymerization reaction of the polymerizable monomer represented by the general formula (1) having a low reactivity. This makes it possible to reduce the amount of residual water and reduce the amount of volatilization.

  That is, after adding the additional polymerization initiator, by maintaining the temperature for a certain time, the polymerization reaction by the added polymerization initiator is newly started, and the reaction of the polymerizable monomer remaining in the reaction system is started. Facilitate. Furthermore, after adding the polymerization initiator, by raising the polymerization temperature, all of the polymerization initiator remaining in the system is decomposed, and further, the polymerization initiator is rapidly decomposed and further unreacted. It becomes possible to accelerate the reaction of the monomer.

  Moreover, in order to promote the lowering of Tg, it is necessary to set the molecular weight low, and a method of increasing the amount of the polymerization initiator as compared with the conventional method is adopted. However, in this method, the polymerization reaction is promoted and the oligomer (2 amounts) is used. The amount of low molecular weight components such as isomers and trimers also increases, which adversely affects the heat resistant storage stability. For this reason, it is possible to proceed in a desired state by adding an additional polymerization initiator after the polymerization initiator added in the initial stage of polymerization is sufficiently consumed while suppressing the total amount of polymerization initiator.

[Compound represented by the general formula (1)]
The present invention is characterized by including a compound (monomer) represented by the following general formula (1) as a copolymer component of a resin.

Formula _{(1) H 2 C = CH} -COOR
In the formula, R represents an alkyl group having 3 to 12 carbon atoms. Specific examples of the compound include propyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, n-octyl acrylate, and 2-ethylhexyl acrylate. N-butyl acrylate and 2-ethylhexyl acrylate are preferred.

  The copolymer component of the compound (monomer) represented by the general formula (1) needs to be contained in an amount of 20 to 45% by mass, preferably 20 to 30% by mass. If it is less than 20% by mass, the low-temperature fixability is difficult, and if it exceeds 45% by mass, the heat-resistant storage stability is deteriorated.

[Monomers other than the compound represented by the general formula (1)]
As the copolymer component of the resin according to the present invention, as a monomer other than the compound represented by the general formula (1), styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, Styrene or styrene derivatives such as pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, methacryl T-butyl acid, n-octyl methacrylate, 2-ethyl methacrylate Methacrylate derivatives such as ruhexyl, stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, acrylic acid ester derivatives such as stearyl acrylate, phenyl acrylate, ethylene, propylene, isobutylene Olefins such as vinyl chloride, vinylidene chloride, vinyl bromide, vinyl fluoride, vinylidene fluoride and other halogen-based vinyls, vinyl propionate, vinyl acetate, vinyl benzoate, and other vinyl esters, vinyl methyl ether, vinyl Vinyl ethers such as ethyl ether, vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone, and vinyl hexyl ketone, N-vinyl carbazole, N-vinyl indole, N-vinyl phenyl There are N-vinyl compounds such as loridone, vinyl compounds such as vinylnaphthalene and vinylpyridine, and acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile and acrylamide. These vinyl monomers can be used alone or in combination.

  Further, it is more preferable to use a combination of monomers having an ionic dissociation group as the polymerizable monomer constituting the resin. For example, it has a substituent such as a carboxyl group, a sulfonic acid group, a phosphoric acid group as a constituent group of the monomer, specifically, acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumar Acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester, styrene sulfonic acid, allyl sulfosuccinic acid, 2-acrylamido-2-methylpropane sulfonic acid, acid phosphooxyethyl methacrylate, 3-chloro-2-acid phosphooxy And propyl methacrylate.

  Furthermore, polyfunctionality such as divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol diacrylate, etc. It is also possible to use a crosslinkable resin by using a functional vinyl.

[Toner material, etc.]
For the toner of the present invention, it is preferable to use a colorant, wax (release agent), polymerization initiator, chain transfer agent, surfactant (dispersion stabilizer) and the like.

(Coloring agent)
As the colorant used in the toner of the present invention, carbon black, a magnetic material, a dye, a pigment, and the like can be arbitrarily used. Examples of the carbon black include channel black, furnace black, acetylene black, thermal black, and lamp black. used. Magnetic materials include ferromagnetic metals such as iron, nickel and cobalt, alloys containing these metals, compounds of ferromagnetic metals such as ferrite and magnetite, alloys that do not contain ferromagnetic metals but exhibit ferromagnetism by heat treatment, For example, a kind of alloy called Heusler alloy such as manganese-copper-aluminum, manganese-copper-tin, chromium dioxide, or the like can be used.

  As the dye, C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 122, C.I. I. Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162, C.I. I. Solvent Blue 25, 36, 60, 70, 93, 95, etc. can be used, and mixtures thereof can also be used. Examples of the pigment include C.I. I. Pigment Red 5, 48: 1, 53: 1, 57: 1, 122, 139, 144, 149, 166, 177, 178, 222, C.I. I. Pigment Orange 31 and 43, C.I. I. Pigment Yellow 14, 17, 74, 93, 94, 138, 156, 158, 180, 185, C.I. I. Pigment green 7, C.I. I. Pigment Blue 15: 3, 60, etc. can be used, and a mixture thereof can also be used. The number average primary particle diameter varies depending on the type, but is preferably about 10 to 200 nm.

  As a method for adding a colorant, the polymer particles are colored by adding resin particles at the stage of agglomeration by addition of an aggregating agent. The colorant can be used by treating the surface with a coupling agent or the like.

(Wax (release agent))
Examples of the wax that can be used in the toner of the present invention include conventionally known waxes. Specifically, polyolefin waxes such as polyethylene wax and polypropylene wax, long chain hydrocarbon waxes such as paraffin wax and sazol 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, trimellit Ester waxes such as acid tristearyl and distearyl maleate, amides such as ethylenediamine dibehenyl amide and trimellitic acid tristearyl amide Box, and the like.

  The melting point of the wax is usually 40 to 160 ° C, preferably 50 to 120 ° C, more preferably 60 to 90 ° C. By setting the melting point within the above range, the heat-resistant storage stability of the toner is ensured, and stable toner image formation can be performed without causing cold offset or the like even when fixing at a low temperature. Further, the wax content in the toner is preferably 1 to 30% by mass, and more preferably 5 to 20% by mass.

  Next, the polymerization initiator, chain transfer agent and surfactant used in the toner production method will be described.

(Polymerization initiator)
The resin constituting the toner of the present invention is produced by polymerizing the aforementioned polymerizable monomer, and the following polymerization initiators (radical polymerization initiators) can be used in the present invention.

  Specifically, oil-soluble polymerization initiators include 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis ( Cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, azo- or diazo-based polymerization initiators such as azobisisobutyronitrile, benzoyl peroxide, methyl ethyl ketone peroxide Oxide, diisopropylperoxycarbonate, cumene hydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide, dicumyl peroxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, 2,2-bis- (4,4-t-butylperoxycyclohexyl) propa Tris - include polymeric initiators having a (t-butylperoxy) peroxide polymerization initiator or a peroxide such as triazine in a side chain.

  Moreover, when forming resin particles by an emulsion polymerization method, a water-soluble polymerization initiator (radical polymerization initiator) can be used. Examples of the water-soluble polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate, azobisaminodipropane acetate, azobiscyanovaleric acid and its salts, hydrogen peroxide and the like.

(Chain transfer agent)
A chain transfer agent can be used for the purpose of adjusting the molecular weight of the 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-mercaptopropionate, terpinolene, carbon tetrabromide and α-methyl. Styrene dimer or the like is used.

(Surfactant)
In addition, a dispersion stabilizer can be used to appropriately disperse the polymerizable monomer and the like in the reaction system. Dispersion stabilizers include tricalcium phosphate, magnesium phosphate, zinc phosphate, aluminum phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate , Bentonite, silica, alumina and the like. Furthermore, those generally used as surfactants such as polyvinyl alcohol, gelatin, methylcellulose, sodium dodecylbenzenesulfonate, ethylene oxide adduct, and higher alcohol sodium sulfate can be used as the dispersion stabilizer.

  The surfactant used in the present invention will be described.

  In order to perform polymerization using the above-described polymerizable monomer, it is necessary to disperse oil droplets in an aqueous medium using a surfactant. Although it does not specifically limit as surfactant which can be used in this case, The following ionic surfactant can be mentioned as an example of a suitable thing.

  Examples of ionic surfactants include sulfonates (sodium dodecylbenzenesulfonate, sodium arylalkylpolyethersulfonate, 3,3-disulfonediphenylurea-4,4-diazo-bis-amino-8-naphthol-6 Sodium sulfonate, ortho-carboxybenzene-azo-dimethylaniline, 2,2,5,5-tetramethyl-triphenylmethane-4,4-diazo-bis-β-naphthol-6-sodium sulfonate, etc.), sulfuric acid 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) Beam, calcium oleate and the like).

  Nonionic surfactants can also be used. Specifically, polyethylene oxide, polypropylene oxide, combination of polypropylene oxide and polyethylene oxide, ester of polyethylene glycol and higher fatty acid, alkylphenol polyethylene oxide, ester of higher fatty acid and polyethylene glycol, ester of higher fatty acid and polypropylene oxide, sorbitan ester Etc.

[Toner Production Method]
Next, a method for producing the toner of the present invention will be described.

  In the method for producing a toner of the present invention, a step of copolymerizing a polymerizable monomer containing the compound represented by the general formula (1) to polymerize resin particles, and aggregating and fusing the resin particles and the colorant particles After adding 30% or more of the polymerization initiator in the polymerization step, the polymerization reaction is allowed to proceed at least twice, and when the polymerization rate becomes 90% or more, the remaining polymerization initiator is added. It is the feature to throw in.

  As described above, after the polymerization initiator added at the initial stage of polymerization is sufficiently consumed, the polymerization reaction can be maintained in a preferable state by adding an additional polymerization initiator. Even after the addition of the additional polymerization initiator, gentle polymerization is maintained by maintaining the temperature for a certain period of time. Thereafter, by raising the temperature, all of the polymerization initiator remaining in the system is decomposed, and it is possible to further accelerate the reaction of unreacted monomers by rapidly decomposing the polymerization initiator. .

  If the amount of the polymerization initiator is made as usual, polymerization at the oligomer level is promoted, and as a result, the heat resistant storage stability is adversely affected. For this reason, it is possible to proceed in a desired state by adding an additional polymerization initiator after the polymerization initiator added in the initial stage of polymerization is sufficiently consumed while suppressing the total amount of polymerization initiator.

  The polymerization rate can be calculated by the method described later (measurement of the polymerization rate).

  The method for producing the toner of the present invention will be described in detail below, taking multilayer resin particles (core / shell structure particles) as an example.

For example, it is manufactured through the following steps.
(1) Dissolution / dispersion step for dissolving or dispersing the release agent in the polymerizable monomer (2) Polymerization step for preparing a dispersion of resin particles (3) Resin particles and colorant particles in an aqueous medium Aggregation and fusion step for agglomeration and fusion to obtain core particles (association particles) (4) First aging step for aging the association particles by heat energy to adjust the shape (5) In the core particle dispersion, Shell forming step of adding resin particles for shell and agglomerating and fusing the particles for shell on the surface of core particles to form colored particles of core / shell structure (6) Heating the colored particles of core / shell structure by thermal energy Second aging step for adjusting the shape of the colored particles having a core / shell structure by aging (7) Solid-liquid separation of the colored particles from the cooled colored particle dispersion and removal of the surfactant from the colored particles Washing process (8) Washed colored particles A drying step for drying Further, after the drying process if necessary,
(9) Step of adding an external additive to the dried colored particles The above steps will be described in detail later.

  When the toner of the present invention is produced, first, resin particles and colorant particles are associated and fused to produce core particles (hereinafter referred to as core particles). Next, resin particles are added to the core particle dispersion, and the resin particles are aggregated and fused on the surface of the core particles to coat the surface of the core particles to produce colored particles having a core / shell structure. As described above, the toner of the present invention is a toner having a core / shell structure in which resin particles are added to a dispersion of core particles prepared by various production methods and fused to the core particles.

  The toner of the present invention preferably has a thin shell and a constant film thickness. After the shell formation, a toner having a uniform particle size and a uniform particle size is preferable. In order to produce a toner having such a structure and shape, the core particles are made to have a uniform shape with a uniform particle size, and shell resin particles are added to the core particles to form a shell. Become. In addition, when the shell is formed, the shape of the toner is finally controlled to give an appropriate shape. For that purpose, it is most important to prepare core particles having a uniform shape with uniform particle sizes. is there. With such core particles, resin particles that form a shell are uniformly attached on the surface thereof, and as a result, toner particles having a uniform film thickness can be produced.

  The core particles constituting the toner of the present invention are produced by a production method in which resin particles and colorant particles are aggregated and fused. The shape of the core particles is controlled, for example, by controlling the heating temperature in the aggregation / fusion process and the heating temperature and time in the first aging process.

  The core part constituting the toner of the present invention can be produced, for example, by dissolving or dispersing a release agent component in a polymerizable monomer that forms a resin, and then mechanically dispersing fine particles in an aqueous medium. A method of salting out and fusing the composite resin particles and colorant particles formed through the process of polymerizing the polymerizable monomer by a polymerization method, which will be described later, is preferably used. When the release agent component is dissolved in the polymerizable monomer, the release agent component may be dissolved or melted or dissolved.

  Hereinafter, each manufacturing process of the toner according to the present invention will be described.

(1) Dissolution / dispersion step This step is a step of preparing a radical polymerizable monomer solution in which the release agent compound is dissolved in the radical polymerizable monomer and the release agent compound is mixed.

(2) Polymerization step In a preferred example of this polymerization step, a radical polymerizable monomer solution in which a wax is dissolved or dispersed in an aqueous medium containing a surfactant having a critical micelle concentration (CMC) or less is added. Then, mechanical energy is applied to form droplets, and then a water-soluble radical polymerization initiator is added to advance the polymerization reaction in the droplets. Note that an oil-soluble polymerization initiator may be contained in the droplet. In such a polymerization process, mechanical energy is imparted and forcedly emulsified (formation of droplets) is essential. Examples of the mechanical energy applying means include strong stirring such as homomixer, ultrasonic wave, and manton gorin, or ultrasonic vibration energy applying means.

  By this polymerization step, resin particles containing a wax and a binder resin are obtained. Such resin particles may be colored fine particles or non-colored fine particles. The colored resin particles can be obtained by polymerizing a monomer composition containing a colorant. In addition, when using uncolored resin particles, a dispersion of colorant particles is added to the dispersion of resin particles in the aggregation / fusion process described later to melt the resin particles and the colorant particles. Color particles can be obtained by attaching.

  The polymerization temperature may be any temperature as long as it is equal to or higher than the lowest radical generation temperature of the polymerization initiator, but for example, a range of 50 to 90 ° C. is used. However, it is also possible to perform polymerization at room temperature or higher by using a polymerization initiator that starts at room temperature, for example, a combination of hydrogen peroxide and a reducing agent (ascorbic acid).

  Since the polymerizable monomer represented by the general formula (1) generally has low reactivity and is likely to remain unreacted in the reaction system, the addition of a polymerization initiator during this polymerization step It can be controlled by the method.

  In order to reduce the unreacted polymerizable monomer, it is preferable to add the polymerization initiator again in the late stage of polymerization (polymerization rate is 90% or more). The amount added is preferably 10% by mass or more of the total amount of the polymerization initiator. Further, when the polymerization initiator has a polar group, it is desirable to reduce the amount of the polymerization initiator because there is a concern about moisture adsorption when the toner is produced. Therefore, for example, when performing a multi-stage polymerization reaction, after adding a polymerization initiator in the first stage polymerization reaction and starting the polymerization reaction, several stages of polymerization reaction are performed without additional addition of the initiator. It is preferable to add the polymerization initiator again for the reaction of the unreacted monomer in the latter stage of the polymerization reaction in the final stage.

  Furthermore, in order to promote the polymerization reaction of the unreacted monomer, it is preferable to raise the polymerization temperature.

(3) Aggregation / fusion process As a method of aggregation and fusion in the fusion process, a salting out / fusion method using resin particles (colored or non-colored resin particles) obtained in the polymerization process is preferable. . Further, in the aggregation / fusion process, the internal additive fine particles such as the release agent fine particles and the charge control agent can be aggregated and fused together with the resin particles and the colorant particles.

  The term “salting out / fusion” as used herein means that aggregation and fusion are performed in parallel, and when the particles have grown to a desired particle size, an aggregation terminator is added to stop the particle growth. The heating for controlling the particle shape according to the above is performed continuously.

  The “aqueous medium” in the agglomeration / fusion step is one in which the main component (50% by mass or more) is made of water. Examples of components other than water include organic solvents that dissolve in water, such as methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, and tetrahydrofuran.

  The colorant particles can be prepared by dispersing the colorant in an aqueous medium. The dispersion treatment of the colorant is performed in a state where the surfactant concentration is set to a critical micelle concentration (CMC) or more in water. The disperser used for the dispersion treatment of the colorant is not particularly limited, but preferably an ultrasonic disperser, a mechanical homogenizer, a pressure disperser such as a manton gorin or a pressure homogenizer, a sand grinder, a Getzmann mill, a diamond fine mill, or the like. Examples thereof include a medium type disperser. Moreover, as a surfactant used, the same thing as the above-mentioned surfactant can be mentioned. The colorant (fine particles) may be surface-modified. In the surface modification method of the colorant, the colorant is dispersed in a solvent, the surface modifier is added to the dispersion, and the system is reacted by raising the temperature. After completion of the reaction, the colorant is separated by filtration, washed and filtered with the same solvent, and dried to obtain a colorant (pigment) treated with the surface modifier.

  The salting-out / fusion method, which is a preferred agglomeration and fusion method, is a salting-out method comprising an alkali metal salt, an alkaline earth metal salt, a trivalent salt, etc. in water in which resin particles and colorant particles are present. The agent is added as an aggregating agent having a critical agglomeration concentration or more, and then the salting out is advanced by heating at a temperature equal to or higher than the glass transition point of the resin particles and higher than the melting peak temperature of the mixture. It is a process to be performed. Here, the alkali metal salt and alkaline earth metal salt which are salting-out agents include lithium, potassium, sodium and the like as the alkali metal, and magnesium, calcium, strontium, barium and the like as the alkaline earth metal. Preferably, potassium, sodium, magnesium, calcium, and barium are used.

  When agglomeration and fusion are performed by salting out / fusion, it is preferable to make the time allowed to stand after adding the salting-out agent as short as possible. The reason for this is not clear, but there is a problem that the aggregation state of the particles varies depending on the standing time after salting out, the particle size distribution becomes unstable, and the surface property of the fused toner varies. appear. Further, the temperature for adding the salting-out agent needs to be at least the glass transition point of the resin particles. The reason for this is that if the temperature at which the salting-out agent is added is equal to or higher than the glass transition point of the resin particles, the salting-out / fusion of the resin particles proceeds rapidly, but the particle size cannot be controlled. There arises a problem that particles having a particle size are generated. The range of the addition temperature is not higher than the glass transition point of the resin, but is generally 5 to 55 ° C, preferably 10 to 45 ° C.

  Further, the salting-out agent is added below the glass transition point of the resin particles, and then the temperature is raised as quickly as possible, the temperature is equal to or higher than the glass transition point of the resin particles and is equal to or higher than the melting peak temperature (° C) of the mixture. Heat to. The time until this temperature rise is preferably less than 1 hour. Further, although it is necessary to quickly raise the temperature, the rate of temperature rise is preferably 0.25 ° C./min or more. The upper limit is not particularly clear, but if the temperature is increased instantaneously, salting out proceeds rapidly, so there is a problem that particle size control is difficult, and 5 ° C./min or less is preferable. By this fusion step, a dispersion of associated particles (core particles) formed by salting out / fusion of resin particles and arbitrary fine particles is obtained.

(4) First aging step And, in the present invention, by controlling the heating temperature of the coagulation / fusion step and particularly the heating temperature and time of the first aging step, the particle size is constant and the distribution is narrow. The core particle surface is controlled so as to have a smooth but uniform shape. Specifically, the heating temperature is lowered in the aggregation / fusion process to suppress the progress of fusion between the resin particles to promote homogenization, the heating temperature is lowered in the first aging process, and the time The surface of the core particles is controlled to have a uniform shape by increasing the length.

(5) Shelling step In the shelling step, the resin particle dispersion for the shell is added to the core particle dispersion to agglomerate and fuse the resin particles for the shell onto the surface of the core particles. The resin particles are coated to form colored particles.

  Specifically, the core particle dispersion is added with a dispersion of resin particles for shells while maintaining the temperature in the above-described aggregation / fusion process and the first aging process, and it takes several hours while continuing heating and stirring. Then, the resin particles for shell are slowly coated on the surface of the core particles to form colored particles. The heating and stirring time is preferably 1 to 7 hours, particularly preferably 3 to 5 hours.

(6) Second ripening step Resin for shell which is added to a core particle after adding a terminator such as sodium chloride at the stage where colored particles have reached a predetermined particle size by shelling to stop particle growth. Heating and stirring are continued for several hours in order to fuse the particles. In the shelling step, a shell having a thickness of 100 to 300 nm is formed on the surface of the core particle. In this way, resin particles are fixed to the surface of the core particles to form a shell, and rounded and colored particles having a uniform shape are formed.

  It is possible to control the shape of the colored particles in the true sphere direction by setting the time of the second aging step longer or by setting the aging temperature higher.

(7) Cooling Step / Solid-Liquid Separation / Washing Step This step is a step of cooling (rapid cooling) the dispersion of the colored particles. As a cooling treatment condition, cooling is performed at a cooling rate of 1 to 20 ° C./min. The cooling treatment method is not particularly limited, and examples thereof include a method of cooling by introducing a refrigerant from the outside of the reaction vessel, and a method of cooling by directly introducing cold water into the reaction system.

  In this solid-liquid separation / washing step, a solid-liquid separation process for solid-liquid separation of the colored particles from the dispersion of colored particles cooled to a predetermined temperature in the above-described step, and a solid-liquid separated toner cake (in a wet state) A cleaning treatment is performed to remove deposits such as a surfactant and a salting-out agent from an aggregate obtained by agglomerating certain colored particles into a cake. Here, the filtration method is not particularly limited, such as a centrifugal separation method, a vacuum filtration method using Nutsche or the like, a filtration method using a filter press or the like.

(8) Drying step This step is a step of drying the washed cake to obtain dried colored particles. Examples of the dryer used in this step include a spray dryer, a vacuum freeze dryer, a vacuum dryer, etc., a stationary shelf dryer, a mobile shelf dryer, a fluidized bed dryer, a rotary dryer. It is preferable to use a stirring dryer or the like. The water content of the dried colored particles is preferably 5% by mass or less, and more preferably 2% by mass or less. In addition, when the dried colored particles are aggregated with weak interparticle attractive force, the aggregate may be crushed. Here, as the crushing treatment device, a mechanical crushing device such as a jet mill, a Henschel mixer, a coffee mill, a food processor, or the like can be used.

(9) External Addition Processing Step This step is a step of preparing a toner by mixing the dried colored particles with an external additive as necessary.

  As an external additive mixing device, a mechanical mixing device such as a Henschel mixer or a coffee mill can be used.

  The mass average particle diameter (dispersed particle diameter) of the composite resin particles is preferably in the range of 10 to 1000 nm, more preferably in the range of 30 to 300 nm.

  The mass average particle diameter is measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.).

[Volatilization amount of the compound represented by the general formula (1)]
In the toner of the present invention, the volatilization amount of the compound (monomer) represented by the general formula (1) is required to be 5 ppm or less, preferably 0.1 to 3 ppm with respect to the toner. When the residual amount of the monomer exceeds 5 ppm, the toner odor is generated by heating at the time of fixing as described above, and a plasticizer effect is brought about on the toner. Although it works favorably for low-temperature fixability due to the effect of a plasticizer, the toner tends to aggregate from the viewpoint of heat-resistant storage stability of the toner, and it is necessary to store it at a lower temperature. In addition, toner agglomerates may result in image defects.

  By using the toner production method of the present invention, the residual amount of monomer in the toner can be 5 ppm or less with respect to the toner.

(Quantitative method of volatiles)
The amount of volatile matter (residual monomer) in the toner can be determined by headspace gas chromatography of the copolymerized resin dispersion.

  In the headspace gas chromatography method, the toner is sealed in a container, heated to about the heat fixing temperature of the copying machine, and the gas in the container is quickly injected into the gas chromatograph while the container is full of volatile components. The volatile component is quantified while analyzing and identifying the compound.

  As a method for measuring impurities derived from resins and trace amounts of additives, a method in which a resin or toner is dissolved in a solvent and injected into a gas chromatograph is well known. In this method, impurities or impurities should be measured at the solvent peak. In order to measure the total amount of volatile components, it is preferable to apply the above headspace method. In the headspace method, it is possible to observe all peaks of volatile components by gas chromatograph, and by using an analysis method using electromagnetic interaction, volatile substances and monomers can be detected with high accuracy. Quantification can also be performed.

(Measurement condition)
1. Sample collection A 0.8 g sample is collected in a 20 ml headspace vial. Since the amount of the sample is necessary to calculate the area per mass, it is weighed to 0.01 g. Seal the vial with a septum using a dedicated crimper.

2. Heating the sample Place the vial in a 170 ° C constant temperature bath and heat for 30 minutes.

3. Setting of Gas Chromatography Separation Conditions A column coated with silicon oil SE-30 so as to have a mass ratio of 15% and packed in a column having an inner diameter of 2.5 mm and a length of 30 m is used as a separation column. The separation column is equipped with a gas chromatograph and flows at 50 ml / min as a He carrier. The temperature of the separation column is set at 40 ° C. and held for 3 minutes, and then the temperature is raised to 200 ° C. at 10 ° C./min.

4). Sample injection Remove the vial from the thermostat and immediately inject 1 ml with a gas tight syringe.

5. Calculation Monomer quantification is calculated using a calibration curve prepared in advance for each monomer.

  6). The following configuration is preferable as the apparatus.

(A) Headspace conditions Headspace device: HP7694 Head Space Sampler (manufactured by Hewlett-Packard Company)
Temperature conditions: transfer line 200 ° C, loop temperature 200 ° C
Sample amount: 0.8 g / 20 ml vial (b) GC / MS conditions GC: HP5890 (manufactured by Hewlett-Packard Company)
MS: HP5971 (manufactured by Hewlett-Packard Company)
Column: HP-624 (30 m x inner diameter 0.25 mm)
Oven temperature: initial temperature 40 ° C. (holding time 3 minutes), heating rate 10 ° C./min, ultimate temperature 200 ° C. (holding time 5 minutes)
Measurement mode: SIM (select ion monitor) mode Specific examples of volatile substances quantified by headspace gas chromatography include monomers styrene, o-methylstyrene, acrylic acid, methacrylic acid, ethyl acrylate, acrylic acid Examples include butyl, a crosslinkable monomer, n-octyl mercaptan, n-decyl mercaptan, and the like.

[Tg of toner]
The toner of the present invention needs to have a Tg of 20 to 40 ° C. When the Tg is less than 20 ° C, the heat-resistant storage stability deteriorates, and when it exceeds 40 ° C, the low-temperature fixability becomes difficult.

  In order to make Tg into the range of 20-40 degreeC, the kind and quantity of the monomer which form copolymer resin are adjusted. Propyl acrylate, propyl methacrylate, butyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, and the like are monomers that lower Tg, and styrene, methyl methacrylate, methacrylic acid, and the like are monomers that increase Tg.

  Tg can be measured by a differential scanning calorimetry method, for example, using a DSC-7 differential scanning calorimeter (Perkin Elmer) or a TAC7 / DX thermal analyzer controller (Perkin Elmer).

  As a measurement procedure, 4.5 to 5.0 mg of toner is precisely weighed to 0.01 mg, sealed in an aluminum pan (KITNO.0219-0041), and set in a DSC-7 sample holder. The reference used an empty aluminum pan. As measurement conditions, the measurement temperature is 0 to 200 ° C., the temperature increase rate is 10 ° C./min, the temperature decrease rate is 10 ° C./min, and the heat-cool-heat control is performed. went.

  Tg draws an extension line of the baseline before the rise of the first endothermic peak and a tangent line indicating the maximum inclination between the rising portion of the first endothermic peak and the peak apex, and the intersection is defined as Tg.

[Molecular weight of resin]
The resin constituting the toner of the present invention preferably has a weight average molecular weight (Mw) of 10,000 to 50,000, a number average molecular weight (Mn) of 5,000 to 25,000, and Mw / Mn of 2 to 4.

  By adjusting the kind and amount of the monomer and the molecular weight within these ranges, the toner having Tg of the present invention can be obtained. In addition, when a material having a wide molecular weight distribution is used, it becomes difficult to melt partially, and fixing failure may occur.

  The molecular weight of the resin can be measured by GPC by the following method.

  As a method for measuring the molecular weight of a resin by GPC (gel permeation chromatography), a sample is dissolved in tetrahydrofuran so as to be 1 mg / ml. As dissolution conditions, it is carried out at room temperature for 5 minutes using an ultrasonic disperser. Next, after processing with a membrane filter having a pore size of 0.2 μm, 10 μl of sample solution is injected into GPC.

  The measurement conditions for GPC are shown below.

Apparatus: HLC-8220 (manufactured by Tosoh Corporation)
Column: TSKguardcolum + TSKgelSuperHZM-M 3 series (manufactured by Tosoh Corporation)
Column temperature: 40 ° C
Solvent: Tetrahydrofuran Flow rate: 0.2 ml / min Detector: Refractive index detector (RI detector)
In the measurement of the molecular weight of a sample, the molecular weight distribution of the sample is calculated using a calibration curve measured using monodisperse polystyrene standard particles. Ten polystyrenes for calibration curve measurement were used.

(Measurement of polymerization rate)
The polymerization rate was calculated based on the area ratio of around Mw = 500 in the GPC measurement chart.

  Specifically, a part of the polymerization reaction solution was collected, immediately after solid-liquid separation and dried, and the polymerization rate of the collected resin was calculated by the following formula in the same measurement method as the molecular weight of the resin.

Polymerization rate = (Mw = total peak area of 500 or more) / (Mw = total peak area of 500 or less)
In addition, a solvent peak is not included in the peak below Mw = 500.

(Toner particle size)
As the toner particle diameter of the present invention, the median diameter (D50) on a volume basis is preferably 3 to 8 μm. This is because with this particle size, reproducibility of image quality corresponding to high image quality can be expected.

(Toner circularity)
The toner shape factor (SF-1) of the present invention is preferably 110 to 150. This is because, within the above range, it is easy to achieve both toner transportability and cleanability.

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

  When used as a one-component developer, a non-magnetic one-component developer or a magnetic one-component developer containing about 0.1 to 0.5 μm of magnetic particles in the toner can be used. be able to. Further, it can be mixed with a carrier and used as a two-component developer. In this case, conventionally known materials typified by iron-containing magnetic particles such as iron, ferrite, and magnetite can be used as the magnetic particles of the carrier, but ferrite particles or magnetite particles are particularly preferable. The volume average particle diameter of the carrier is preferably 15 to 100 μm, more preferably 20 to 80 μm.

  The median diameter D50 of the volume-based distribution of the carrier can be measured using a laser diffraction particle size distribution measuring device “HELOS” (manufactured by SYMPATEC).

  The carrier is preferably a coating carrier in which magnetic particles are further coated with a resin, or a so-called resin dispersion type carrier in which magnetic particles are dispersed in a resin. The resin composition for coating is not particularly limited, and for example, olefin resin, styrene resin, styrene-acrylic resin, silicon resin, ester resin, fluorine-containing polymer resin, or the like is used. Moreover, it does not specifically limit as resin for comprising a resin dispersion type carrier, A well-known thing can be used, For example, a styrene-acrylic-type resin, a polyester resin, a fluorine resin, a phenol resin etc. are used. be able to.

  The mixing ratio of the carrier and the toner is preferably in the range of carrier: toner = 1: 1 to 50: 1 in terms of mass ratio.

[Image Forming Method and Image Forming Apparatus Using Toner of Present Invention]
Next, an image forming method in which the toner of the present invention can be used will be described. The toner of the present invention is preferably used in, for example, a high-speed full-color image forming apparatus having a printing speed of 300 mm / sec or higher (65 sheets / min output performance in terms of A4 paper) level or higher. Specifically, a printer or the like that can create a large amount of documents on demand in a short time can be mentioned. Further, the present invention can be applied to an image forming method in which the temperature of the fixing roller is set to 150 ° C. or lower, preferably 130 ° C. or lower.

  FIG. 1 is an example of an image forming apparatus capable of using the toner of the present invention, and shows a cross-sectional view thereof.

  Each color image formed by the image forming units 9Y, 9M, 9C, and 9K is sequentially primary-transferred onto the rotating intermediate transfer body 6 by the transfer means 7Y, 7M, 7C, and 7K, and the combined color image. Is formed.

  The paper P stored in the paper feed cassette 20 as the paper feed means is fed one by one by the paper feed roller 21, is conveyed to the transfer means 7 A through the registration roller 22, and the color image is transferred onto the paper P. Is secondarily transferred.

  The paper P on which the color image has been transferred is fixed by the fixing device 17 which is a fixing device of the present invention, and is sandwiched by the paper discharge roller 25 through the transport rollers 23 and 24 which are transport means, and is discharged outside the machine. It is placed on the paper tray 26.

  FIG. 2 is a cross-sectional view showing an example of the fixing device 17 that can be used in the image forming apparatus of FIG. 1, and includes a heating roller 17a and a pressure roller 17b that contacts the heating roller 17a. In FIG. 2, T is a toner image formed on a transfer paper (image forming support) P.

  In the heating roller 17a, a coating layer 171 made of a fluororesin or an elastic body is formed on the surface of the cored bar 172, and includes a heating member 173 made of a linear heater.

  The cored bar 172 is made of metal and has an inner diameter of 10 to 70 mm. Although it does not specifically limit as a metal which comprises the metal core 172, For example, metals, such as iron, aluminum, copper, or these alloys can be mentioned.

  The thickness of the cored bar 172 is set to 0.1 to 15 mm, and is determined in consideration of the balance between the energy saving requirement (thinning) and the strength (depending on the constituent materials). For example, in order to maintain the same strength as that of a cored bar made of iron of 0.57 mm with a cored bar made of aluminum, the wall thickness needs to be 0.8 mm.

  Examples of the fluororesin constituting the coating layer 171 include PTFE (polytetrafluoroethylene) and PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer).

  The thickness of the coating layer 171 made of a fluororesin is 10 to 500 μm, preferably 20 to 400 μm. Examples of the elastic body constituting the coating layer 171 include silicone rubber and silicone sponge rubber having good heat resistance such as LTV, RTV, and HTV. The Asker C hardness of the elastic body constituting the coating layer 171 is less than 80 °, preferably less than 60 °. The thickness of the coating layer 171 made of an elastic body is 0.1 to 30 mm, preferably 0.1 to 20 mm.

  As the heating member 173, a halogen heater can be preferably used.

  The pressure roller 17 b is formed by forming a coating layer 174 made of an elastic body on the surface of the cored bar 175. The elastic body constituting the covering layer 174 is not particularly limited, and examples thereof include various soft rubbers such as urethane rubber and silicone rubber, and sponge rubber, and the silicone rubber and the silicone sponge rubber exemplified as those constituting the covering layer 174. Is preferably used. The Asker C hardness of the elastic body constituting the coating layer 174 is less than 80 °, preferably less than 70 °, and more preferably less than 60 °. The thickness of the covering layer 220 is 0.1 to 30 mm, preferably 0.1 to 20 mm.

  Although it does not specifically limit as a material which comprises the metal core 175, Metals, such as aluminum, iron, copper, or those alloys can be mentioned.

  The contact load (total load) between the heating roller 17a and the pressure roller 17b is usually 40 to 350N, preferably 50 to 300N, and more preferably 50 to 250N. This contact load is defined in consideration of the strength of the heating roller 17a (the thickness of the cored bar 110). For example, a heating roller having a cored bar made of iron of 0.3 mm should be 250 N or less. Is preferred.

Further, from the viewpoint of offset resistance and fixability, the nip width is preferably 4 to 10 mm, and the surface pressure of the nip is preferably 0.6 × 10 ^{5 to} 1.5 × 10 ⁵ Pa. .

  The image forming apparatus according to the present invention may use an induction heating type fixing device instead of the heating roll type fixing device.

  The transfer material P used in the present invention is a support for holding a toner image, and is usually called an image support, a recording material, or transfer paper. Specifically, various transfer materials such as plain paper and fine paper from thin paper to thick paper, coated printing paper such as art paper and coated paper, commercially available Japanese paper and postcard paper, plastic film for OHP, cloth, etc. However, it is not limited to these.

  EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these embodiments. In addition, the following "part" represents a "mass part".

Example << Preparation of Resin Particle 1 >>
(First polymerization)
175 g of styrene
60 g of n-butyl acrylate
Methacrylic acid 15g
n-Octyl mercaptan 7g
The monomer mixture solution was put in a 5 L stainless steel kettle equipped with a stirrer, and 100 g of pentaerythritol tetrabehenate was added thereto, heated to 70 ° C. and dissolved to prepare a monomer solution.

  On the other hand, a surfactant solution in which 2 g of sodium polyoxyethylene (2) dodecyl ether sulfate is dissolved in 1350 ml of ion-exchanged water is heated to 70 ° C., added to the monomer solution, mixed, and then mechanically dispersed having a circulation path. Dispersion was performed at 70 ° C. for 30 minutes using a machine CLEARMIX (M Technique Co., Ltd.) to prepare an emulsified dispersion.

  Next, a polymerization initiator solution in which 7.0 g of potassium persulfate was dissolved in 150 ml of ion-exchanged water was added to this emulsified dispersion, and the system was polymerized by heating and stirring at 78 ° C. for 1.5 hours. A latex was obtained. This is designated as Latex 1.

(Second polymerization (formation of outer layer))
To the latex 1 obtained as described above, an initiator solution in which 12 g of potassium persulfate is dissolved in 220 ml of ion-exchanged water is added, and under the temperature condition of 80 ° C.,
Styrene 334.4g
n-Butyl acrylate 81.9g
Methacrylic acid 38.7g
n-Octyl mercaptan 7.5g
The monomer mixture consisting of was added dropwise over 1 hour. After completion of the dropping, the polymerization is progressed while measuring the polymerization rate with GPC. When the polymerization rate reaches 90%, a polymerization initiator solution in which 2.28 g of potassium persulfate is dissolved in 75 ml of ion-exchanged water is added. The system was heated and stirred at 90 ° C. for 1 hour to complete the polymerization reaction, and then cooled to 28 ° C. to obtain a latex. This latex is referred to as resin particle 1 (core latex).

<< Preparation of Resin Particles 2 and 5 >>
As shown in Table 1, the amount of polymerization initiator in (first polymerization), the polymerizable monomer copolymerization ratio in (second polymerization), and the amount of polymerization initiator added during the preparation of resin particles 1 are as shown in Table 1. Resin particles 2 and 5 were prepared in the same manner except for the above.

<< Preparation of Resin Particles 3 and 4 >>
In the preparation of the resin particle 1, 108.75 g of styrene (first polymerization), 120 g of 2-ethylhexyl acrylate, 21.25 g of methacrylic acid, and the polymerization initiator amount was changed as shown in Table 1, ( Resin particles 3 and 4 were prepared in the same manner except that the polymerizable monomer copolymerization ratio in the second polymerization) and the amount of polymerization initiator added during the polymerization were changed as shown in Table 1.

<< Preparation of Resin Particle 6 >>
In the preparation of the resin particles 1, 193.75 g of styrene (first polymerization), 35 g of n-butyl acrylate and 21.25 g of methacrylic acid were changed, and the polymerization initiator amount was changed as shown in Table 1, ( Resin particles 6 were prepared in the same manner except that the polymerizable monomer copolymerization ratio in the second polymerization) and the amount of polymerization initiator added during the polymerization were changed as shown in Table 1.

<< Preparation of Resin Particle 7 >>
In the preparation of the resin particle 1, the styrene of (first polymerization) was 101.25 g, n-butyl acrylate was 127.5 g, methacrylic acid was 21.25 g, and the polymerization initiator amount was changed as shown in Table 1. Resin particles 7 were prepared in the same manner except that the polymerizable monomer copolymerization ratio in (second polymerization) and the amount of polymerization initiator added during the polymerization were changed as shown in Table 1.

<< Preparation of resin particles for shell >>
A surfactant solution in which 8 g of sodium dodecyl sulfate was dissolved in 3 L of ion-exchanged water was charged into a 5 L stainless steel kettle (SUS kettle) equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introducing device. The liquid temperature was raised to 80 ° C. while stirring at a stirring speed.

  To this surfactant solution, a polymerization initiator solution in which 10 g of potassium persulfate was dissolved in 200 g of ion-exchanged water was added, the temperature was adjusted to 80 ° C., and the following monomer mixture was added dropwise over 100 minutes. Polymerization was performed by heating and stirring at 80 ° C. for 2 hours to prepare resin particles for shells.

Styrene 570g
165 g of n-butyl acrylate
Methacrylic acid 70g
n-octyl mercaptan 5.5 g
<< Production of Toner 1 >>
(Preparation of Colorant Particle Dispersion 1)
90 parts of polyoxyethylene (2) sodium dodecyl ether sulfate was dissolved in 1600 parts of ion-exchanged water with stirring. While stirring this solution, 400 parts of carbon black “Regal 330” (Cabot Corporation) is gradually added, followed by a dispersion treatment using a stirring device “Claremix” (Mtechnic Co., Ltd.), and a coloring agent. A particle dispersion 1 was prepared.

(Salting out / fusion (association / fusion) process) (core formation)
Reaction vessel equipped with 420.7 parts (in terms of solid content) of resin particles 1, 900 parts of ion-exchanged water, and 200 parts of colorant particle dispersion 1, and a temperature sensor, a cooling pipe, a nitrogen introducing device, and a stirring device. And stirred. After adjusting the temperature in a container to 30 degreeC, 5 mol / liter sodium hydroxide aqueous solution was added to this solution, and pH was adjusted to 8-11.

  Next, an aqueous solution in which 2 parts of magnesium chloride hexahydrate was dissolved in 1000 parts of ion-exchanged water was added over 10 minutes at 30 ° C. with stirring. After standing for 3 minutes, the temperature was raised and the system was heated to 65 ° C. over 60 minutes. While confirming the particle diameter with the Coulter Multisizer 3, when the volume median diameter reached 6.5 μm, an aqueous solution in which 40.2 parts of sodium chloride was dissolved in 1000 parts of ion-exchanged water was added to increase the particle diameter. Further, as a ripening treatment, the fusion was continued by heating and stirring at a liquid temperature of 70 ° C. for 1 hour, whereby the core portion 1 was formed.

(Formation of shell layer (shelling operation))
Next, 96 parts of resin particles for shells were added at 65 ° C. (in terms of solid content), and an aqueous solution in which 2 parts of magnesium chloride hexahydrate was dissolved in 1000 parts of ion-exchanged water was added over 10 minutes. The temperature is raised to 70 ° C. (shelling temperature), stirring is continued for 1 hour, and the particles of the resin particles 1 for the shell layer are fused to the surface of the core portion 1, followed by aging treatment at 75 ° C. for 20 minutes. And a shell layer was formed.

  Here, 40.2 parts of sodium chloride was added, cooled to 30 ° C. under the condition of 8 ° C./min, and the generated fused particles were filtered and repeatedly washed with 45 ° C. ion-exchanged water. By drying with warm air, a toner base 1 having a volume median diameter of 6.6 μm and having a shell layer on the surface of the core was obtained.

(External additive treatment)
Toner base 1 is 1% by weight of hydrophobic silica (number average primary particle size = 12 nm, degree of hydrophobicity = 68) and 1.2% of hydrophobic titanium oxide (number average primary particle size = 20 nm, degree of hydrophobicity = 63). Toner 1 was prepared by adding a mass% and mixing with a Henschel mixer.

<< Production of Toners 2-6 >>
Toners 1 to 6 having a volume median diameter of 6.6 μm were prepared in the same manner except that the resin particles 1 were changed to resin particles 2 to 6 in the production of the toner 1.

<< Preparation of developer >>
Next, a ferrite carrier having a volume average particle diameter of 50 μm coated with a silicone resin was mixed with each of the toners prepared above, and developers 1 to 6 having a toner concentration of 6% were prepared.

<Evaluation>
The produced toner was measured and evaluated as follows.

(Quantification of residual monomer)
The amount of residual monomer in the toner was quantified by the headspace gas chromatography described above.

(Measurement of Mw and Mn of resin particles)
Mw and Mn of the binder resin of the toner were measured after removing the colorant with a membrane filter by the GPC (gel permeation chromatograph) described above.

(Create print image)
The evaluation was performed on the following items in an environment of 20 ° C. and 55% RH by sequentially loading the developer prepared above into a digital color multifunction machine bizhub PRO C500 (manufactured by Konica Minolta Business Technologies). The print is an A4 size fine paper (64 g / m ² ) of an image with a pixel rate of 10% (original image with character image 7%, human face photo, solid white image, solid black image each 1/4). )

<Low temperature fixability>
The heating roller surface temperature of the fixing device of the evaluation machine is changed so that the paper surface temperature changes within a range of 80 to 150 ° C. in increments of 10 ° C., and the toner image is fixed at each changed temperature to produce a fixed image. did. In creating the printed image, high-quality paper (80 g / m ² ) of A4 size was used.

  The fixing strength of the printed image obtained by fixing is fixed using a method in accordance with the mending tape peeling method described in Chapter 9 Section 1.4 of “Basics and Applications of Electrophotographic Technology: Electrophotographic Society”. The rate was evaluated.

Specifically, after creating a 2.54 cm square solid black print image with a toner adhesion amount of 0.6 mg / cm ² , the image density before and after peeling with a scotch mending tape (manufactured by Sumitomo 3M) was measured. The residual ratio of image density was determined as a fixing ratio.

  The transfer material (paper) surface temperature at which the fixing rate is 95% or more is defined as the minimum fixing temperature. The surface temperature of the transfer material (paper) was measured with a non-contact thermometer. The image density was measured with a reflection densitometer “RD-918” (manufactured by Macbeth).

Evaluation criteria A: Fixing is possible at a minimum fixing temperature of less than 100 ° C. ○: Fixing is possible at a minimum fixing temperature of 100 ° C. or more and less than 130 ° C. ×: Fixing is possible at a minimum fixing temperature of 130 ° C. or more.
100 half-tone images having an image density of 0.4 were printed on both sides of A4 quality fine paper (64 g / m ² ), and the occurrence of white spots due to missing transfer was visually evaluated.

Evaluation criteria ◎: No transfer omissions ○: 1 to 2 transfer omissions exist only on the back side per 100 sheets of prints, but there is no practical problem because they must be stared. △: 1 to 2 units per 50 prints There is a slight problem in practical use, and there is a problem in practical use. X: There are five or more clear transfer defects in 50 prints regardless of the front and back, and there is a problem in practical use.

<Half tone unevenness>
Using the 100th image printed in the transfer omission evaluation, the image was visually evaluated. The evaluation is as follows.

◎: Unevenness is not recognized ○: Slight unevenness is confirmed but there is no practical problem ×: Unevenness is recognized and there is practical problem <Striped defect>
After completion of evaluation of transfer omission and halftone unevenness, 10000 sheets were printed in a high-temperature and high-humidity environment (33 ° C., 80% RH), and the halftone portion of the 10,000th printed image was visually observed to check for scratches. Evaluation was performed.

◎: No scratch, no problem ○: Level of scratches, no problem in practical use △: Level of practical use in two scratches ×: Level of practical use in three or more scratches <Odor during image formation>
Ten people engaged in the light printing industry became monitors, and the odor at the fixing portion after the end of the 10,000th image of the streak defect evaluation was evaluated.

◎: 8 or more of 10 people do not care about odor ○: 6 or more of 10 people have some odor but are not uncomfortable ×: 5 or more of 10 people complain of discomfort due to odor The results of measurement and evaluation are shown in Tables 2 and 3.

  From the table, the toner of the present invention is a toner for developing an electrostatic image that has both low-temperature fixability and heat-resistant storage stability (no image defects such as transfer loss, halftone unevenness, streak failure, etc.) and does not generate odor. I understand.

FIG. 3 is a cross-sectional view of an image forming apparatus in which the toner of the present invention can be used. FIG. 3 is a cross-sectional view illustrating an example of a heating roll type fixing device. It is a sectional view showing an example of a fixing device of a type using a belt and a heating roller.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 9Y, 9M, 9C, 9K Image forming unit 6 Intermediate transfer body 17 Fixing apparatus T Toner

Claims (3)

In the toner for developing an electrostatic image containing a resin obtained by copolymerizing a polymerizable monomer containing a compound represented by the following general formula (1), the composition of the compound represented by the general formula (1) with respect to the resin The ratio is 20 to 45% by mass, the volatilization amount of the compound represented by the general formula (1) is 5 ppm or less with respect to the electrostatic image developing toner, and the glass transition point is 20 to 40 ° C. A toner for developing an electrostatic charge image.
Formula _{(1) H 2 C = CH} -COOR
(In the formula, R represents an alkyl group having 3 to 12 carbon atoms.) 2. The electrostatic charge image developing according to claim 1, wherein the resin has a weight average molecular weight (Mw) of 10,000 to 50,000, a number average molecular weight (Mn) of 5,000 to 25000, and Mw / Mn of 2 to 4. toner. For electrostatic image development, comprising the steps of copolymerizing a polymerizable monomer containing a compound represented by the following general formula (1) to polymerize resin particles, and aggregating and fusing the resin particles and colorant particles In the toner production method, in the polymerization step, the polymerization reaction is performed n times (where n is 2 or more), and the polymerization initiator is added in two portions. 30% by mass or more of the polymerization initiator amount is charged, and when the polymerization rate of the n-th polymerization reaction becomes 90% or more, the remaining polymerization initiator amount is charged. Toner manufacturing method.
Formula _{(1) H 2 C = CH} -COOR
(In the formula, R represents an alkyl group having 3 to 12 carbon atoms.)

Images