JP2010020147A - Method of producing toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of producing a core-shell structure type toner in which, when shell forming resin particles are added to a core particle dispersion liquid, the shell forming resin particles deposit uniformly on the core particle surface without causing homo aggregation, so that even shell formation is performed. <P>SOLUTION: In the method of producing the toner, when resin particles and a polyvalent metal salt are added to a core particle dispersion liquid containing at least a resin and a colorant to perform shell formation, after adding the resin particles, the polyvalent metal salt is added within 15-70% of the time required for a shell forming step. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing a toner used for electrophotographic image formation, and forms a shell by aggregating resin particles on the surface of core particles containing at least a resin and a colorant to form a core-shell structure toner. The present invention relates to a toner manufacturing method.

  In recent years, in electrophotographic image forming apparatuses, so-called low-temperature fixing technology capable of fixing a toner image at a lower temperature than before has been studied in order to reduce power consumption and realize high-speed printing. It was. One of the performances required for toners that achieve low-temperature fixing is improved meltability at low temperatures. Examples of techniques for realizing this include, for example, resins having low glass transition temperatures and softening points of toner constituent resins, There is a method of using a low melting point wax.

As described above, the toner using a resin having a low glass transition temperature and a low softening point can fix the toner image at a temperature lower than the conventional one, but it is not used because it sacrifices thermal stability. The toner has a problem called blocking where the toners stick to each other. Therefore, a core-shell structure toner has been developed in which the problem of blocking is solved by coating a thermally stable resin on the surface of particles composed of a resin having a low glass transition temperature or softening point (for example, Patent Document 1). In the core-shell toner, thermally stable resin particles are added together with an aggregating agent to a core particle dispersion made of resin that contributes to low-temperature fixing, and thermally stable resin particles adhere to the surface of the core particles and agglomerate. To form a shell.
Japanese Patent Laid-Open No. 11-231570

  When producing a toner having a core-shell structure, in the step of forming the shell, it is required that the thermally stable resin particles be uniformly adhered to the surface of the core particles without unevenness. However, since the resin constituting the core particle and the resin particle for the shell have a difference in physical properties, it is surprisingly difficult to form a uniform shell on the surface of the core particle, and the homoaggregation in which the added resin particles for the shell are aggregated The occurrence of could not be ignored. Therefore, even if an attempt is made to produce a toner having a core-shell structure, a low-temperature fixing toner that does not cause blocking when stored in a high-temperature environment cannot be stably produced because the shell is not sufficiently formed.

  An object of the present invention is to provide a toner manufacturing method capable of uniformly forming a shell on the surface of core particles without unevenness. That is, when shell-forming resin particles are added to the core particle dispersion, the shell-forming resin particles do not cause homo-aggregation under the flocculant, and can evenly adhere and agglomerate uniformly on the core particle surface. An object of the present invention is to provide a method for producing a toner.

  The present inventor has found that the above-described problem can be solved by any of the configurations described below.

The invention described in claim 1
“A method for producing a toner having a shelling step in which a resin particle and a polyvalent metal salt are added to a core particle dispersion containing at least a resin and a colorant to form a shell on the surface of the core particle. And
In the shelling step,
After the resin particles are added, the polyvalent metal salt is added during 15% to 70% of the time required for the shelling step. ].

The invention described in claim 2
The toner manufacturing method according to claim 1, wherein the metal salt is magnesium chloride. ].

The invention according to claim 3
3. The toner production method according to claim 1, wherein the toner has a glass transition temperature of 30 ° C. to 45 ° C. ].

  According to the present invention, when a toner having a core-shell structure is produced, the shell can be uniformly formed on the surface of the core particles without unevenness. That is, in the shell forming step, the resin particles for forming the shell added to the core particle dispersion can be uniformly adhered and aggregated on the surface of the core particles without causing homoaggregation by the action of the aggregating agent. became.

  Therefore, a core-shell toner with a uniform shell formed on the surface of the core particles can be reliably obtained, and it is thermally stable without causing blocking of toner particles even when stored in a high temperature environment. New low-temperature fixing toner can be provided.

  The present invention relates to a method for producing a toner comprising a step of forming a shell on the surface of a core particle by adding a resin particle for forming a shell and a polyvalent metal salt into a core particle dispersion containing at least a resin and a colorant. About.

  Hereinafter, the present invention will be described in detail.

  The present inventor has found that the effect of the present invention can be achieved by specifying the timing when the polyvalent metal salt is added after the addition of the resin particles for forming the shell. That is, at the time of forming the shell, the resin particles are added and then the shell is formed by adding a polyvalent metal salt during 15% to 70% of the time required for forming the shell. It is now possible to provide a toner having a core-shell structure with improved storability.

  The reason why a toner having both the low temperature fixability and the storage stability can be obtained by specifying the addition timing of the polyvalent metal salt as the flocculant and shelling is because the following mechanism occurs. it is conceivable that. First, after adding the resin particles for shell formation, the resin particles can be uniformly dispersed with a margin in the dispersion. The shell-forming resin particles are sufficiently uniformly dispersed in the dispersion to form a state in which many shell-forming resin particles are uniformly present around the core particle having a large particle size with the same probability. The By adding a polyvalent metal as a flocculant in this state, the shell-forming resin particles do not cause homo-aggregation between the shell-forming resin particles so that the shell-forming resin particles stick to the nearby core particles having a large particle size. It is thought that the shell can be smoothly formed by adhesion and aggregation.

  In this way, a uniform dispersion state of the shell-forming resin particles is formed in the core particle dispersion so that it is uniformly present around the core particles, and an environment in which the resin particles can uniformly adhere to the surface of the core particles uniformly. It is presumed that it can be shelled because it is formed. Therefore, when the polyvalent metal salt is added at a stage of less than 15% of the time required for shell formation, the resin particles for shell formation are not yet uniformly dispersed, so homoaggregation is likely to occur, and stable shell formation is achieved. It is thought that it can not be done. Further, when the polyvalent metal salt is added at a stage exceeding 70% of the time required for shell formation, there is not enough time for the shell forming resin particles to aggregate on the surface of the core particles, so that the shell can be sufficiently formed. It is thought that it will disappear.

  A process of forming a shell constituting the toner manufacturing method according to the present invention will be described with reference to FIG. FIG. 1 is a schematic diagram for explaining the timing of adding a polyvalent metal salt in the shelling step, and the horizontal axis in the figure represents the time axis.

  First, the “required time for the step of forming a shell” in the present invention, that is, the “shell forming step time” is from when the shell-forming resin particles are added to the core particle dispersion as shown in FIG. It means the time until the aggregation terminator is added. Here, assuming that the entire “shell forming process time” is 100%, “15% of the time required for the shell forming process” and “70% of the time required for the shell forming process” are defined as follows. The

  First, “15% of the time required for the process of forming the shell”, that is, “15% of the time for forming the shell” is based on the timing shown in FIG. 1, that is, when the resin particles for forming the shell are added. This is when 15% of the total time required for the shelling process has elapsed. Specifically, for example, when the “shelling process time” is 100 minutes, it means that 15 minutes have elapsed since the addition of the shell-forming resin particles.

  Further, “70% of the time required for the process of forming the shell”, that is, “70% of the time for forming the shell”, as shown in FIG. 1, is converted into the shell based on the addition of the resin particles for forming the shell. This refers to when 70% of the total process time has elapsed. Specifically, for example, when the “total time required for the shelling process” is 100 minutes, it means that 70 minutes have elapsed after the addition of the shell-forming resin particles.

  In the present invention, by forming a shell by adding a polyvalent metal salt within the time indicated by the dashed arrow in FIG. 1, it is possible to produce a toner that does not cause blocking in an image formation by low-temperature fixing and in a high-temperature environment. it can.

  Next, the “polyvalent metal salt” added in the shelling step will be described. As described above, in the present invention, resin particles are attached to and agglomerated on the surface of the core particles to produce a core-shell structure toner. After adding the resin particles for shell formation, 15% of the time required for the shelling process is 15%. The polyvalent metal salt which is a flocculant is added between ˜70%. Here, the “polyvalent metal salt” is a compound containing a divalent or higher valent metal atom in the structure, and is usually also called an inorganic metal salt, and the metal atom forms a compound by ionic bond. It will be.

  Some of the polyvalent metal salts used in the shelling step constituting the present invention contain a divalent metal atom called an alkaline earth metal salt. That is, from alkaline earth metal atoms such as magnesium, calcium, strontium and barium and counter ions (anions constituting the salt) such as chloride ions, bromide ions, iodide ions, nitrate ions, carbonate ions and sulfate ions. It is composed. There are also inorganic metal salts formed by bonding aluminum atoms or zinc atoms to the counter ions.

  Specific examples of the polyvalent metal salt include, for example, calcium chloride, calcium nitrate, barium chloride, magnesium chloride, magnesium sulfate, magnesium carbonate, zinc chloride, aluminum chloride, aluminum sulfate and the like. There are also called inorganic metal salt polymers such as polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. Among these, magnesium salts are preferable, magnesium chloride and magnesium sulfate are more preferable, and magnesium chloride is particularly preferable. That is, the magnesium salt is preferable because the shell-forming resin particles can be adhered and aggregated on the surface of the core particles with a small addition amount compared to other polyvalent metal salts. Among these, when magnesium chloride is used, the resin particles can be adhered and aggregated on the surface of the core particles with the smallest amount, which is particularly preferable.

  The addition amount of the polyvalent metal salt is preferably 0.5 to 20% by mass with respect to the solid content (core particles, shell-forming resin particles) in the core particle dispersion, although it varies depending on the ion concentration during the shelling step. . When the addition amount of the flocculant is 0.5 to 20% by mass, the resin particles for forming the shell can be efficiently attached and aggregated on the surface of the core particles. This is preferable because it can be reliably removed from the surface. That is, since the polyvalent metal salt is surely removed from the toner particle surface in the washing step, it is effective in stabilizing the charging property of the toner. In particular, when magnesium chloride is used, as described above, good aggregation performance can be obtained with a small addition amount, and thus a toner having more stable chargeability can be obtained.

  Next, the core-shell toner manufactured by the toner manufacturing method according to the present invention will be described. The toner produced in the present invention has a structure called a core-shell structure formed by coating a resin and forming a layer called a shell on the surface of a particle called a core made of a resin containing at least a colorant. . An example of a core-shell toner is shown in FIG. The toner T shown in FIG. 1 includes a core A made of a resin 2 containing a colorant 1 and a shell B formed by coating the resin 3 on the surface of the core A.

  The toner T shown in FIG. 1A has a structure in which the shell B completely covers the surface of the core A. The toner according to the present invention is not limited to one having a structure in which the shell B completely covers the core A as shown in FIG. 1A. For example, as shown in FIG. Includes a structure in which the core A is not completely covered and the core A is exposed in some places.

  That is, the core-shell toner in the present invention refers to a toner having a structure in which approximately 30% or more of the core surface is covered with the shell B.

  Further, in the present invention, the term “shell formation” is also used, but the resin 3 phase, which is a shell-forming resin, is added to the dispersion of core A to coat the surface of resin 3 on the surface of core A. The formation is called “shell formation”.

  For example, the toner T in FIG. 1B shows a state where the shell B covers 30% or more and less than 100%, preferably 50% or more and 95% or less of the surface of the core A. In addition, although the toner T in FIG. 1C has some unevenness on the surface of the core A, the shape of the toner T after the shell formation is rounded due to, for example, part of the shell B entering the inside of the core A. It is something that is tinged.

  The cross-sectional structure of the toner produced in the present invention and the shell coverage on the core surface can be confirmed by observing with, for example, a transmission electron microscope (TEM) or a scanning probe microscope (SPM). The scanning probe microscope (SPM) can evaluate the physical properties such as the hardness of the resin constituting the toner in addition to the observation of the sectional shape of the toner.

  A method for observing the cross-sectional structure of the toner with a transmission electron microscope (TEM) will be described. Regarding the cross-sectional structure of the toner, the method for observing the cross-sectional structure of the toner with a transmission electron microscope can observe the prepared sample from a photographed image, for example, by the following procedure.

  First, after sufficiently dispersing the toner in a room temperature curable epoxy resin, embedding and dispersing in a fine styrene powder having a particle size of about 100 nm, and then performing pressure molding to form a block containing the toner. Make it. If necessary, the prepared block is dyed with ruthenium tetroxide or osmium tetroxide if necessary, and then a microtome with diamond teeth is used to form a flake shape having a thickness of 80 to 200 nm. The sample for a measurement is produced.

  The measurement sample thus thinned is set on a transmission electron microscope (TEM), and the cross-sectional structure of the toner is photographed. At this time, the magnification of the electron microscope is preferably a magnification that allows the cross section of one toner to enter the field of view, and specifically about 10,000 times. Further, it is preferable that the number of toners to be photographed with a transmission electron microscope is at least 10 or more.

  Observation of the cross-sectional structure of the toner with a transmission electron microscope can be sufficiently handled by a model that is generally well known among those skilled in the art. For example, “LEM-2000 type (manufactured by Topcon)” And “JEM-2000FX (manufactured by JEOL Ltd.)”.

  The toner according to the present invention has a core-shell structure. When a photograph of the photographed cross-sectional structure is observed, a region where a colorant or the like is present and a region where these are not present are confirmed, and a boundary serving as an interface between the core and the shell. Can be confirmed.

  The coverage of the shell on the core surface is calculated by processing the captured image information with an image processing apparatus “Luzex F” (manufactured by Nireco) using a transmission electron microscope (TEM). That is, the area of the core region and the shell region of the photographed toner is calculated by the arithmetic processing using “Luzex F”, and the average coverage of the shell on the core surface is calculated from the cross-sectional structure photograph of at least 10 toners. Is possible.

  Further, the toner production method according to the present invention is particularly preferable as a method for producing a toner having a glass transition temperature of 30 ° C. to 45 ° C. That is, since a shell can be uniformly formed on the core surface by adding a polyvalent metal salt during 15% to 70% of the time required for the shelling process, the softness is exhibited at room temperature and the particles adhere to each other. It is possible to uniformly coat the core surface that is liable to cause a shell with a shell. As a result, even with toner using a core having a low glass transition temperature, a uniform shell is formed, so that even when stored in a high temperature and high humidity environment for a long period of time, toners do not adhere to each other, and high definition images Formation can be ensured for a long time. Further, it is possible to stably provide a toner compatible with so-called low-temperature fixing that fixes a toner image at a temperature lower than that in the past.

  The glass transition temperature of the toner can be measured using, for example, “DSC-7 differential scanning calorimeter (manufactured by Perkin Elma)” or “TAC7 / DX thermal analysis controller (manufactured by PerkinElmer)”. As a measurement procedure, first, toner 4.5 mg to 5.0 mg is precisely weighed to two digits after the decimal point, and this is enclosed in an aluminum pan (KIT No. 0219-0041) and set in a DSC-7 sample holder. . The reference uses an empty aluminum pan. The measurement conditions are a measurement temperature of −30 ° C. to 200 ° C., a temperature increase rate of 10 ° C./min, a temperature decrease rate of 10 ° C./min, and heat-cool-heat temperature control, and analysis is performed based on the data in the 2nd Heat. Do.

  For the glass transition temperature, an extension line of the baseline before the rise of the first endothermic peak and a tangent line showing the maximum inclination between the rising portion of the first endothermic peak and the peak vertex are drawn, and the intersection is shown as the glass transition temperature. .

  Next, a toner manufacturing method according to the present invention will be described.

  The present invention relates to a toner having a core-shell structure in which colored particles constituting the toner (toner base particles before external addition treatment) coat a resin on the surface of a core made of a resin containing at least a colorant to form a shell. Is produced. The toner manufacturing method according to the present invention includes a step of forming a shell on the core particle surface by adding resin particles and a polyvalent metal salt to a core particle dispersion containing at least a resin and a colorant. It has a conversion process.

  In the step of forming the shell, after the resin particles for forming the shell are added to the core particle dispersion, the polyvalent metal salt is added during 20% to 80% of the time required for the shell forming step. . The toner manufacturing method according to the present invention has the above-described configuration.

  As a method for producing a toner by forming a shell on the surface of the core particle by such a procedure, there is a toner production by a polymerization method. Toner production by polymerization is easy to form the desired toner while controlling the shape and size of the particles in the production process, so it is ideal for production of small diameter toner that can faithfully reproduce minute dot images. is there.

  Among the toner preparation methods based on this polymerization method, a method called an emulsion association method is one of the preferred methods for preparing a toner having a core-shell structure. In the emulsion association method, first, resin particles of around 120 nm are formed in advance by an emulsion polymerization method or a suspension polymerization method, and the resin particles are aggregated to form core particles. Further, a core-shell toner can be produced by agglomerating and fusing thermally stable resin particles of around 120 nm on the surface of the core particles in the shell forming step.

Hereinafter, an example of producing a toner having a core-shell structure by an emulsion association method will be described. In the emulsification association method, a toner is generally prepared through the following procedure. That is,
(1) Preparation process of resin fine particle dispersion for core formation (2) Preparation process of fine colorant particle dispersion (3) Aggregation / fusion process of resin particles for core (4) First aging process (5) Shelling process (6) Second aging step (7) Cooling step (8) Cleaning step (9) Drying step (10) External additive treatment step Hereinafter, each step will be described.

(1) Production process of resin fine particle dispersion In this process, a polymerizable monomer that forms the resin particles for the core is put into an aqueous medium and polymerized to form resin fine particles having a size of about 120 nm. It is a process. In this step, it is possible to form a resin fine particle containing a wax. In this case, the wax is dissolved or dispersed in a polymerizable monomer, and this is polymerized in an aqueous medium. Resin fine particles containing wax are formed.

(2) Colorant fine particle dispersion preparation step In this step, a colorant is dispersed in an aqueous medium to prepare a colorant fine particle dispersion having a size of about 110 nm.

(3) Aggregation and fusion process of core particles (core formation)
This step is a step of aggregating the aforementioned resin fine particles, colorant fine particles, and fine particles expressing rubber elasticity in an aqueous medium, and fusing these agglomerated particles to produce core particles. . In this step, after adding an alkali metal salt or an alkaline earth metal salt as an aggregating agent to an aqueous medium in which resin particles and colorant particles are mixed, the mixture is melted at a temperature equal to or higher than the glass transition temperature of the resin particles. Heating below the peak temperature causes the agglomeration to proceed and simultaneously fuses the resin particles.

  Specifically, the resin particles and the colorant particles produced by the above-described procedure are added to the reaction system, and a coagulant such as magnesium chloride is added to agglomerate the resin particles and the colorant particles at the same time. Particles are formed by fusing together. Then, when the particle size reaches the target size, a salt such as saline is added to stop aggregation.

(4) First aging step This step is a step of aging until the shape of the core becomes a desired shape by heat-treating the reaction system following the above-described aggregation / fusion step.

(5) Shelling step This step is a step of adding a shell-forming resin particle to the core particle dispersion subjected to the first aging step to form a shell on the core surface. In the present invention, after addition of the shell-forming resin particles, a polyvalent metal salt that is an aggregated salt is added to the core particle dispersion at a timing of 15% to 70% of the shelling process time. By adding the polyvalent metal salt at the above timing, the shell-forming resin particles can adhere and aggregate on the surface of the core particles without causing homoaggregation in the shelling step.

(6) Second aging step In this step, following the shelling step, the reaction system is heat-treated to strengthen the coating of the shell on the core surface, and until the colored particles have a desired shape. This is the process of aging.

(7) Cooling 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.

(8) Washing step This step consists of a filtration step for solid-liquid separation of the particles from the particle dispersion cooled to the predetermined temperature in the above step, and a surfactant from the particles solid-liquid separated into wet cake-like aggregates. And a cleaning step for removing deposits such as aggregating agent.

  In the washing treatment, the filtrate is washed with water until the electric conductivity of the filtrate reaches 10 μS / cm. Examples of the filtration method include a centrifugal separation method, a vacuum filtration method using Nutsche and the like, a filtration method using a filter press and the like, and are not particularly limited.

(9) Drying step This step is a step of drying the washed particles to obtain dried particles. Dryers used in this process include spray dryers, vacuum freeze dryers, vacuum dryers, etc. Among them, stationary shelf dryers, mobile shelf dryers, fluidized bed dryers, rotary dryers, A stirring dryer or the like is preferable.

  The moisture of the dried particles is preferably 5% by mass or less, and more preferably 2% by mass or less. In addition, when the dried particles are aggregated due to weak interparticle attractive force, the aggregate may be crushed. Here, as the crushing processing apparatus, a mechanical crushing apparatus such as a jet mill, a Henschel mixer, a coffee mill, or a food processor can be used.

(10) External additive treatment step This step is a step of preparing a toner by mixing the dried particles with an external additive as necessary. As an external additive mixing apparatus, a mechanical mixing apparatus such as a Henschel mixer or a coffee mill can be used.

  The toner production method by the emulsion association method is one in which the toner is produced through the above-described steps. For the reasons described above, the core-shell structure toner according to the present invention is preferably produced by the emulsion association method.

  Next, components such as a resin, a colorant, and a wax that can be used for the toner produced in the present invention will be described with specific examples.

First, as a resin that can be used in the toner according to the present invention, a polymer prepared by polymerizing a polymerizable monomer represented by a vinyl monomer as shown in the following (1) to (10): Is a typical one. That is, the resin that can be used in the toner according to the present invention can be obtained by polymerizing the following vinyl monomers alone or in combination.
(1) Styrene or styrene derivatives Styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-tert- Butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, etc. (2) Methacrylate derivatives Methyl methacrylate, methacryl Ethyl acetate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, diethyl methacrylate (3) Acrylic acid ester derivatives Methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, phenyl acrylate, and the like.
(4) Olefins Ethylene, propylene, isobutylene, etc. (5) Vinyl esters Vinyl propionate, vinyl acetate, vinyl benzoate, etc. (6) Vinyl ethers Vinyl methyl ether, vinyl ethyl ether, etc. (7) Vinyl ketones Vinyl methyl ketone, Vinyl ethyl ketone, vinyl hexyl ketone, etc. (8) N-vinyl compounds N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone, etc. (9) Vinyl compounds Vinyl naphthalene, vinyl pyridine, etc. (10) Acrylic acid or methacrylic acid Derivatives Acrylonitrile, methacrylonitrile, acrylamide, etc.

  Moreover, it is also possible to use combining the polymerizable monomer which has an ionic dissociation group as a polymerizable monomer which comprises resin. Examples of the ionic dissociation group include substituents such as a carboxyl group, a sulfonic acid group, and a phosphoric acid group. The polymerizable monomer having an ionic dissociation group has these substituents.

  Specific examples of the polymerizable monomer having an ionic dissociation group are given below.

  Acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumaric 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 phosphooxypropyl methacrylate, and the like.

  Furthermore, it is also possible to use a polyfunctional vinyl as a polymerizable monomer constituting the resin to obtain a resin having a crosslinked structure. Specific examples of the polyfunctional vinyls are listed below.

  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, and the like.

  Next, known colorants can be used for the toner prepared in the present invention. Specific colorants are shown below.

  Examples of the black colorant include carbon black such as furnace black, channel black, acetylene black, thermal black, and lamp black, and magnetic powder such as magnetite and ferrite.

Examples of the colorant for orange or yellow include the following pigments. That is,
C. I. Pigment Orange 31 and 43, C.I. I. Pigment Yellow 3, 9, 12, 13, 14, 15, 15, 35, 36, 65, 74, 83, 98, 111, 139, 153, 181 etc.

Further, as the colorant for magenta or red, there are the following pigments. That is,
C. I. Pigment Red 2, 3, 5, 6, 7, 9, 15, 16, 48: 1, 48: 3, 53: 1, 57: 1, 81: 4, 122, 123, 139, 144, 149, 166, 177, 178, 208, 209, 222, etc.

  Further, as a colorant for green or cyan, C.I. I. Pigment Blue 15, 15: 2, 15: 3, 15: 4, 16, 60, 62, 66, C.I. I. Pigment Green 7 etc.

The toner produced in the present invention may contain a wax together with a resin and a colorant. Specific examples of the wax include the following.
(1) Polyolefin waxes such as polyethylene wax and polypropylene wax (2) Long chain hydrocarbon waxes such as paraffin wax, sazol wax and microcrystalline wax (3) Dialkyl ketone waxes such as distearyl ketone (4) Carna Uba wax, montan wax, trimethylolpropane tribehenate, pentaerythritol tetramyristate, pentaerythritol tetrastearate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, behenyl behenate, glycerin tribehenate , 1,18-octadecanediol distearate, tristearyl trimellitic acid, ester waxes such as distearyl maleate (5) ethylenediamine dibe Niruamido, amide waxes such as trimellitic acid tristearyl amide.

  The melting point of the wax usable for the toner prepared in the present invention is usually 40 to 125 ° C., preferably 50 to 120 ° C., more preferably 60 to 90 ° C. In addition, any of the above waxes can be used alone, or a plurality of types can be used in combination.

  By using a wax having a melting point in the above range, the heat-resistant storage stability of the toner is ensured. Further, even when so-called low-temperature fixing in which a toner image is fixed at a fixing temperature lower than that in the past, stable image formation can be performed without causing a cold offset or the like. Further, the addition amount of the wax is preferably 1 to 30% by mass and more preferably 5 to 20% by mass with respect to the whole toner. By setting the added amount of wax within the above range, smooth separation characteristics are exhibited at the time of fixing, and the transparency of the toner image is not lowered.

  In addition, a known charge control agent can be added to the toner produced in the present invention. The charge control agent is not particularly limited, and as the negative charge control agent, a colorless, white, or light color charge control agent that does not adversely affect the color tone and translucency of the toner can be used. Specific examples of the negative charge control agent include the following. Examples include salicylic acid derivative metals, calixarene compounds, organic boron compounds, and fluorine-containing quaternary ammonium salt compounds.

  As the above-mentioned salicylic acid metal complex, for example, those described in JP-A Nos. 53-127726 and 62-145255 can be used. As the calixarene compound, for example, those described in JP-A-2-2013378 can be used. Moreover, as an organic boron compound, the thing as described in Unexamined-Japanese-Patent No. 2-221967 etc. can be used, for example. Moreover, as an organic boron compound, the thing as described in Unexamined-Japanese-Patent No. 3-1162 etc. can be used, for example. The addition amount of these charge control agents is preferably 0.1 to 10 parts by mass, and more preferably 0.5 to 5.0 parts by mass with respect to 100 parts by mass of the binder resin.

  Next, in the toner prepared in the present invention, particles such as inorganic fine particles and organic fine particles having a number average primary particle size of 40 to 800 nm are added as external additives (= external additives) in the external additive processing step described above. Thus, a toner can be produced.

  By adding the external additive, the fluidity and chargeability of the toner are improved, and the cleaning property is improved. The type of external additive is not particularly limited, and examples thereof include inorganic fine particles, organic fine particles, and lubricants listed below.

  A conventionally well-known thing can be used as an inorganic fine particle. Specifically, silica, titania, alumina, strontium titanate fine particles and the like can be preferably used. These inorganic fine particles may be hydrophobized as necessary. Specific examples of the silica fine particles include commercially available products R-805, R-976, R-974, R-972, R-812, R-809 manufactured by Nippon Aerosil Co., Ltd., HVK-2150, H manufactured by Hoechst Co., Ltd. -200, commercially available products TS-720, TS-530, TS-610, H-5, MS-5, etc. manufactured by Cabot Corporation.

  As the titania fine particles, for example, commercially available products T-805 and T-604 manufactured by Nippon Aerosil Co., Ltd., commercially available products MT-100S, MT-100B, MT-500BS, MT-600, MT-600SS, JA- 1. Commercial products TA-300SI, TA-500, TAF-130, TAF-510, TAF-510T manufactured by Fuji Titanium Co., Ltd. Commercial products IT-S, IT-OA, IT-OB, IT- manufactured by Idemitsu Kosan Co., Ltd. OC etc.

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

  As the organic fine particles, spherical organic fine particles having a number average primary particle diameter of about 10 to 2000 nm can be used. Specifically, homopolymers such as styrene and methyl methacrylate and copolymers thereof can be used.

  Further, it is possible to use a lubricant to further improve the cleaning property and the transfer property. Examples of the lubricant include metal salts of higher fatty acids such as the following. That is, salts of zinc stearate, aluminum, copper, magnesium, calcium, etc., zinc oleate, salts of manganese, iron, copper, magnesium, etc., zinc palmitate, salts of copper, magnesium, calcium, etc., linoleic acid There are salts of zinc, calcium and the like, and zinc and calcium of ricinoleic acid.

  The addition amount of these external additives and lubricants is preferably 0.1 to 10.0% by mass with respect to the whole toner. As a method for adding external additives and lubricants, there are methods using various known mixing devices such as a Turbula mixer, a Henschel mixer, a Nauter mixer, and a V-type mixer.

  The toner according to the present invention can be used as a two-component developer composed of a carrier and a toner, or as a non-magnetic one-component developer composed only of a toner.

  When the toner constituting the full-color toner kit according to the present invention is used as a two-component developer, for example, a full-color print can be created at a high speed using a tandem image forming apparatus described later. In addition, by selecting a resin or wax constituting the toner, it is possible to produce a full color print by so-called low-temperature fixing in which the paper temperature during fixing is about 100 ° C.

  In addition, carriers that are magnetic particles used when used as a two-component developer are conventionally known, for example, metals such as iron, ferrite, and magnetite, and alloys of these metals with metals such as aluminum and lead. It is possible to use materials. Among these, ferrite particles are preferable. The carrier has a volume average particle size of preferably 15 to 100 μm, more preferably 25 to 80 μm.

  The toner image formed using the toner according to the present invention is transferred onto the transfer paper P and fixed on the transfer paper P by a fixing process. The transfer paper P here is a support for holding the toner image transferred from the image carrier, and is usually called an image support, a recording material, transfer paper, or paper. Specifically, various types of transfer such as plain paper and high-quality paper from thin paper to heavy paper, coated printing paper such as art paper and coated paper, commercially available Japanese paper and postcard paper, plastic film for OHP, cloth, etc. There are materials.

Next, an image forming method performed using the toner produced in the present invention will be described. Some electrophotographic image forming methods performed using the toner produced in the present invention include, for example, the following steps. That is,
(1) Electrostatic latent image forming step for forming an electrostatic latent image on an electrostatic latent image carrier (photosensitive member) (2) Using the developer containing the toner according to the present invention, an electrostatic latent image is formed. Development process for developing a toner image by developing the electrostatic latent image formed on the image carrier (3) Transfer for transferring the toner image formed on the electrostatic latent image carrier onto a transfer body such as paper Step (4) A fixing step of fixing the toner image transferred onto the transfer body.

  In addition, you may have other processes other than the said 4 processes. For example, it is preferable to have a cleaning step of removing toner remaining on the surface of the electrostatic latent image carrier after transferring the toner image. In the transfer step, the toner image from the electrostatic latent image carrier onto the recording medium may be transferred via an intermediate transfer member.

  According to the image forming method using the toner produced in the present invention, so-called low-temperature fixing is possible. Further, by realizing the low-temperature fixing, it becomes possible to suppress the energy consumption during image formation as compared with the conventional one.

  FIG. 3 is a schematic view showing an example of an image forming apparatus that can be used when the toner according to the present invention is used as a two-component developer.

  In FIG. 3, 1Y, 1M, 1C and 1K are photosensitive members, 4Y, 4M, 4C and 4K are developing devices (developing means), 5Y, 5M, 5C and 5K are primary transfer rolls as primary transfer means, and 5A. Are secondary transfer rolls as secondary transfer means, 6Y, 6M, 6C and 6K are cleaning devices, 7 is an intermediate transfer member unit, 24 is a heat roll type fixing device, and 70 is an intermediate transfer member.

  This image forming apparatus is called a tandem color image forming apparatus, and includes a plurality of sets of image forming units 10Y, 10M, 10C, and 10K, an endless belt-shaped intermediate transfer body unit 7 as a transfer unit, and a recording member P. It has an endless belt-like paper feeding and conveying means 21 for conveying and a heat roll type fixing device 24 as a fixing means. A document image reading device SC is disposed above the main body A of the image forming apparatus.

  An image forming unit 10Y that forms a yellow image as one of the different color toner images formed on each photoconductor is arranged around a drum-shaped photoconductor 1Y as the first photoconductor and the photoconductor 1Y. The charging unit 2Y, the exposure unit 3Y, the developing unit 4Y, the primary transfer roll 5Y as the primary transfer unit, and the cleaning unit 6Y are provided. The image forming unit 10M that forms a magenta image as another different color toner image includes a drum-shaped photoconductor 1M as a first photoconductor, and a charge disposed around the photoconductor 1M. Means 2M, exposure means 3M, developing means 4M, primary transfer roll 5M as primary transfer means, and cleaning means 6M. In addition, an image forming unit 10C that forms a cyan image as one of toner images of different colors is a drum-shaped photoconductor 1C as a first photoconductor, and a charge disposed around the photoconductor 1C. Means 2C, exposure means 3C, developing means 4C, primary transfer roll 5C as primary transfer means, and cleaning means 6C.

  Further, the image forming unit 10K that forms a black image as one of the other different color toner images includes a drum-shaped photoconductor 1K as a first photoconductor, and a charge disposed around the photoconductor 1K. Means 2K, exposure means 3K, developing means 4K, primary transfer roll 5K as primary transfer means, and cleaning means 6K.

  The endless belt-like intermediate transfer body unit 7 has an endless belt-like intermediate transfer body 70 as an intermediate transfer endless belt-like second image carrier that is wound around a plurality of rolls and is rotatably supported.

  Each color image formed by the image forming units 10Y, 10M, 10C, and 10K is sequentially transferred onto the rotating endless belt-shaped intermediate transfer body 70 by the primary transfer rolls 5Y, 5M, 5C, and 5K, and is combined. A colored image is formed. A recording member P such as a sheet as a transfer material accommodated in the sheet feeding cassette 20 is fed by the sheet feeding / conveying means 21, passes through a plurality of intermediate rolls 22 A, 22 B, 22 C, 22 D, and a registration roll 23, and is secondary. A color image is transferred onto the recording member P at a time by being conveyed to a secondary transfer roll 5A as a transfer means. The recording member P to which the color image has been transferred is fixed by the heat roll type fixing device 24, is sandwiched by the paper discharge roll 25, and is placed on the paper discharge tray 26 outside the apparatus.

  On the other hand, after the color image is transferred to the recording member P by the secondary transfer roll 5A, the residual toner is removed by the cleaning unit 6A from the endless belt-shaped intermediate transfer body 70 in which the recording member P is separated by curvature.

  During the image forming process, the primary transfer roll 5K is always in pressure contact with the photoreceptor 1K. The other primary transfer rolls 5Y, 5M, and 5C are in pressure contact with the corresponding photoreceptors 1Y, 1M, 1C, and 1R, respectively, only during color image formation.

  The secondary transfer roll 5A comes into pressure contact with the endless belt-shaped intermediate transfer body 70 only when the recording member P passes through the secondary transfer roll 5A and secondary transfer is performed.

  In this manner, toner images are formed on the photoreceptors 1Y, 1M, 1C, 1R, and 1K by charging, exposure, and development, and the toner images of the respective colors are superimposed on the endless belt-shaped intermediate transfer body 70 and recorded collectively. The image is transferred to the member P and fixed by the fixing device 24 by pressure and heating. The photoreceptors 1Y, 1M, 1C, and 1K after transferring the toner image to the recording member P are cleaned with the cleaning device 6A to remove the toner remaining on the photoreceptor, and then the above charging, exposure, and development cycle. The next image formation is performed.

  The full-color image forming method using a non-magnetic one-component developer includes, for example, image formation in which the developing means 4 for the two-component developer described above is replaced with a known developing means for a non-magnetic one-component developer. This can be realized by using an apparatus.

  When the toner produced in the present invention is used in an image forming apparatus compatible with low-temperature fixing, the surface temperature of the heating member in the fixing device is in the above range, particularly less than 140 ° C., and the surface temperature of the heating member is less than 125 ° C. It is possible to set.

  Hereinafter, as a specific example of the fixing device, a fixing device using a heating roller and a fixing device including a heating roller and a pressure belt will be described. FIG. 4 is a schematic diagram illustrating an example of a fixing device using a heating roller.

  The fixing device 24 shown in FIG. 4 includes a heating roll 240 and a pressure roll 241 in contact with the heating roll 240. In FIG. 4, 246 is a separation claw, and P is a paper (transfer paper) on which a toner image is formed.

  The heating roll 240a has, for example, a coating layer 82 made of a fluororesin or an elastic body formed on the surface of the cored bar 240a, and includes a heating member 244 made of a linear heater.

  The core metal 240 is made of metal and has an inner diameter of 10 to 70 mm. Although the metal which comprises the metal core 240 is not specifically limited, For example, there exist metals, such as iron, aluminum, copper, these alloys, etc.

  The thickness of the core metal 240a is 0.1 to 15 mm, and is preferably determined in consideration of a balance between a request for energy saving (thinning) and strength (depending on constituent materials). For example, in order to maintain the same strength as a cored bar made of iron of 0.57 mm with a cored bar made of aluminum, the thickness is preferably about 0.8 mm.

  Examples of the fluororesin constituting the surface of the coating layer 240c include polytetrafluoroethylene (PTFE) and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA).

  The coating layer 240c made of a fluororesin has a thickness of 10 to 500 μm, preferably 20 to 400 μm.

  When the thickness of the coating layer 240c made of a fluororesin is less than 10 μm, the function as the coating layer cannot be sufficiently exhibited, and it becomes difficult to ensure the durability as the fixing device. On the other hand, when the thickness of the coating layer 240c exceeds 500 μm, the surface of the coating layer is easily damaged by paper powder. Since toner or the like is likely to adhere to the generated scratched part, there is a concern about the occurrence of image smearing due to this.

  Further, as the elastic body constituting the covering layer 240c, it is preferable to use silicon rubber, silicon sponge rubber, or the like having good heat resistance such as LTV, RTV, HTV and the like.

  The Asker C hardness of the elastic body constituting the coating layer 240c is less than 80 °, preferably less than 60 °.

  Moreover, 0.1-30 mm is preferable and, as for the thickness of the coating layer 240c, 0.1-20 mm is more preferable.

  As the heating member 244, a halogen heater can be preferably used.

  The pressure roll 250 is formed by forming a coating layer 250b made of an elastic body on the surface of the cored bar 250a. The elastic body constituting the covering layer 250b is not particularly limited, and includes various soft rubbers such as urethane rubber and silicon rubber, and sponge rubber, among which silicon rubber and silicon sponge rubber are preferable.

  The thickness of the coating layer 250b is preferably 0.1 to 30 mm, and more preferably 0.1 to 20 mm.

  The fixing temperature (the surface temperature of the heating roll 240) is a temperature at which the temperature of the paper can be set to around 100 ° C. during fixing, and is 70 to 180 ° C., although it depends on the fixing linear speed described later. The fixing linear velocity is preferably 80 to 640 mm / sec, and the nip width between the heating roll 240 and the pressure roll 250 is set to 8 to 40 mm, preferably 11 to 30 mm.

  The separation claw 246 is provided to prevent the sheet heat-fixed on the heating roll 240 from being wound around the heating roll.

  When using the toner produced in the present invention, it is preferable to use a fixing device having a structure capable of efficiently supplying heat supplied from the heating member to the paper. Specifically, it is preferable to use a fixing device called a belt fixing that uses a heat-resistant belt as either the heating member or the pressure member.

  FIG. 5 shows an example of a belt fixing type fixing device (a type using a belt and a heating roller). The fixing device 24 shown in FIG. 5 is a type using a belt and a heating roller in order to secure a nip width, and is pressed against the heating roller 240 via the heating roller 240, the seamless belt 241, and the seamless belt 241. The pressure pad (pressure member) 242a, the pressure pad (pressure member) 242b, and the lubricant supply member 243 constitute main parts.

  The heating roller 240 is formed of a heat-resistant elastic layer 240b and a release layer (heat-resistant resin layer) 240c around a metal core (cylindrical core) 240a, and a heat source is provided inside the core 240a. A halogen lamp 244 is arranged. The surface temperature of the heating roller 240 is measured by the temperature sensor 245, and the halogen lamp 244 is feedback-controlled by a temperature controller (not shown) based on the measurement signal so that the surface of the heating roller 240 is adjusted to a constant temperature. The seamless belt 241 is in contact with the heating roller 240 so as to be wound at a predetermined angle to form a nip portion.

  Inside the seamless belt 241, a pressure pad 242 having a low friction layer on its surface is arranged in a state of being pressed against the heating roller 240 via the seamless belt 241. The pressure pad 242 is provided with a pressure pad 242a to which a strong nip pressure is applied and a pressure pad 242b to which a weak nip pressure is applied, and is held by a holder 242c made of metal or the like.

  A belt traveling guide is attached to the holder 242c so that the seamless belt 241 slides and rotates smoothly. The belt running guide is preferably a member having a low coefficient of friction because it rubs against the inner surface of the seamless belt 241, and a member having low thermal conductivity is preferred so that heat is not easily taken from the seamless belt 241. A specific example of the material of the seamless belt 241 is, for example, polyimide.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to the following description content. In the following description, “part” means “part by mass”.

1. 1. Production of “Toners 1 to 10” 1-1. Production of “Toner 1” (1) Production of “Core Forming Resin Fine Particle 1” First, “Core Forming Resin Fine Particle 1” was produced by the following procedure.
(A) First-stage polymerization Anionic surfactant polyoxy (2) dodecyl ether sulfate sodium salt 4.0 parts by mass and ion-exchanged water in a reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introduction device 3000 parts by mass was added to prepare a surfactant solution. The surfactant solution was heated to 80 ° C. while stirring under a nitrogen stream.

  After raising the temperature to 80 ° C., an initiator aqueous solution in which 10 parts by mass of potassium persulfate (KPS) is dissolved in 400 parts by mass of ion-exchanged water is added to bring the liquid temperature to 75 ° C. Body mixed solution 1 "was added dropwise over 1 hour.

Styrene 532 parts by weight n-butyl acrylate 200 parts by weight Methacrylic acid 68 parts by weight n-octyl mercaptan 16 parts by weight After adding “monomer mixed solution 1” dropwise to the surfactant solution, the system is heated at 75 ° C. Polymerization (first stage polymerization) was carried out by heating and stirring for 2 hours to produce “resin fine particle dispersion a1”.
(B) Second-stage polymerization In a reaction vessel equipped with a stirrer, temperature sensor, cooling pipe, and nitrogen introduction device, 3.0 parts by weight of anionic surfactant polyoxy (2) dodecyl ether sulfate sodium salt and ion-exchanged water A surfactant solution was prepared by charging 3060 parts by mass. The surfactant solution was heated to 80 ° C. while stirring under a nitrogen stream.

  After the temperature rise, 35 parts by mass of the resin fine particles a1 (in terms of solid content) and a mixed liquid containing the following compound are added, and a mechanical dispersion device “CLEAMIX (M Technique Co., Ltd.)” having a circulation path is added. Was mixed and dispersed for 30 minutes to prepare an emulsified particle (oil droplet) dispersion.

Styrene 100 parts by weight n-butyl acrylate 62 parts by weight Methacrylic acid 12 parts by weight n-octyl mercaptan 1.75 parts by weight Paraffin wax “HNP-57 (manufactured by Nippon Wax Co., Ltd.)” 96 parts by weight Next, the emulsified particle dispersion An initiator aqueous solution prepared by dissolving 5 parts by mass of potassium persulfate (KPS) in 100 parts by mass of ion-exchanged water was added to the system, and the system was heated and stirred at 80 ° C. for 1 hour to perform polymerization (first reaction). Two-stage polymerization) was performed.
(C) Third-stage polymerization After the second-stage polymerization, an initiator aqueous solution prepared by dissolving 5.45 parts by mass of potassium persulfate (KPS) in 220 parts by mass of ion-exchanged water is added, and the reaction system is added. At 80 ° C., and a mixture of the following compounds was added dropwise over 1 hour.

Styrene 294 parts by mass n-butyl acrylate 155 parts by mass n-octyl mercaptan 7.1 parts by mass After completion of dropping, the mixture was heated and stirred for 2 hours to conduct polymerization (third stage polymerization), and then the reaction system was 28 ° C. The resin fine particles were produced by cooling to a low temperature. The obtained resin fine particles are referred to as “core-forming resin fine particles 1”.

  The formed “core-forming resin fine particles 1” had a weight average molecular weight of 21,600, a mass average particle diameter of 170 nm, and a glass transition temperature of 43.5 ° C.

(2) Production of “core-forming resin fine particles 2” In the production of “core-forming resin fine particles 1”, the addition amount of the compound used in the first stage polymerization was changed as follows.

Styrene 511 parts by mass n-butyl acrylate 226 parts by mass Methacrylic acid 68 parts by mass n-octyl mercaptan 16 parts by mass The addition amount of the compound used in the second stage polymerization was changed as follows.

Styrene 98 parts by weight n-butyl acrylate 71 parts by weight Methacrylic acid 12 parts by weight n-octyl mercaptan 1.75 parts by weight Paraffin wax “HNP-57 (manufactured by Nippon Wax Co., Ltd.)” 96 parts by weight Further, used in the third stage polymerization The addition amount of the compound was changed as follows.

Styrene 287 parts by mass n-butyl acrylate 174 parts by mass n-octyl mercaptan 7.1 parts by mass The “core-forming resin fine particles 2” were formed by processing under the same conditions except for the above-mentioned changes. The formed “core forming resin fine particles 2” had a weight average molecular weight of 22,800, a mass average particle diameter of 165 nm, and a glass transition temperature of 28.7 ° C.
(3) Production of “shell forming resin fine particle dispersion” Prepared at the time of the first stage polymerization of “core forming resin fine particles 1” in a reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introducing device. The same surfactant solution was prepared. While this surfactant solution was stirred at a stirring speed of 230 rpm under a nitrogen stream, the internal temperature was raised to 80 ° C. Thereafter, an initiator solution prepared by dissolving 10 parts by mass of potassium persulfate (KPS) in 400 parts by mass of ion-exchanged water is added to the surfactant solution, and the liquid temperature is set to 80 ° C. The body mixed solution "was added dropwise over 2 hours.

And it superposed | polymerized by heating and stirring process at 80 degreeC over 2 hours, and produced "resin fine particle 1 dispersion liquid for shell formation." The monomer mixed solution is
Styrene 624 parts by mass 2-ethylhexyl acrylate 120 parts by mass Methacrylic acid 56 parts by mass n-octyl mercaptan (NOM) 16.4 parts by mass.

  The formed “shell-forming resin particles 1” had a weight average molecular weight of 23,800, a mass average particle diameter of 120 nm, and a glass transition temperature of 86.7 ° C.

(4) Preparation of “Colorant Dispersion 1” A solution prepared by stirring and dissolving 90 parts by weight of sodium dodecyl sulfate in 1600 parts by weight of ion-exchanged water was stirred, and carbon black “Regal 330R ( 420 parts by mass of “Cabot Corporation” was gradually added. Subsequently, a dispersion process was performed using a stirrer “CLEARMIX (M Technique Co., Ltd.)” to prepare “Colorant Dispersion Liquid 1”.

(5) "Aggregation / fusion process (formation of cores 1 and 2)"
In a reaction vessel equipped with a stirrer, temperature sensor, cooling pipe, nitrogen introduction device,
"Core-forming resin fine particles 1" 360.6 parts by mass (solid content conversion)
Ion-exchanged water 1100 parts by mass “Colorant Dispersion 1” 200 parts by mass (in terms of solid content)
The liquid temperature was adjusted to 30 ° C. Thereafter, a 5 mol / liter aqueous sodium hydroxide solution was added to adjust the pH to 10.0.

  The reaction system was allowed to stir, and in this state, an aqueous solution prepared by dissolving 60 parts by mass of magnesium chloride hexahydrate in 60 parts by mass of ion-exchanged water was added to the reaction system over 10 minutes. After the addition, the mixture was allowed to stand for 3 minutes, and then the temperature increase was started. The system was heated to 80 ° C. over 60 minutes, and the particles were agglomerated while maintaining the temperature at 80 ° C. to grow the particles. In this state, the particle size of the aggregated particles was measured using “Multisizer 3 (manufactured by Beckman Coulter)”. When the volume-based median system (D50) reached 6.5 μm, an aqueous solution obtained by dissolving 40 parts by mass of sodium chloride in 160 parts by mass of ion-exchanged water was added to the reaction system to stop particle growth.

  Further, the temperature of the reaction system was set to 70 ° C. for 3 hours, and the particles were continuously fused by heating and stirring, and an aging treatment was performed to form a dispersion of “core 1”. The average circularity of “Core 1” was measured by “FPIA 2100 (manufactured by Sysmex Corporation)” and found to be 0.905.

  The same procedure was used except that 360.6 parts by mass (in terms of solid content) of “core forming resin fine particles 2” was used instead of “core forming resin fine particles 1” used in the preparation of “core 1”. Thus, “Core 2” was formed. The average circularity of “Core 2” was 0.905, which is the same as “Core 1”.

(6) “Shelling process”
Next, to the dispersion of “core 1”,
"Shell-forming resin fine particles 1" 44 parts by mass (solid content conversion)
Was added.

  In this state, after stirring for 13 minutes while raising the temperature of the reaction system to 80 ° C., an aqueous solution in which 30 parts by mass of magnesium chloride hexahydrate was dissolved in 1000 parts by mass of ion-exchanged water was applied for 3 minutes. Added.

  After the above magnesium chloride hexahydrate is added, stirring is continued for 74 minutes in this state to fuse the “shell-forming resin particles 1” to the surface of the “core 1” and further ripen to form a shell. Went.

  Further, an aging treatment was performed by adding an aqueous solution in which 150 parts by mass of sodium chloride was dissolved in 600 parts by mass of ion-exchanged water. When the average circularity reached 0.940, the condition was 30 ° C. under the condition of 8 ° C./min. To “colored particles 1 having a core-shell structure”. The formed “colored particles 1” had a glass transition temperature of 45.5 ° C.

(7) “Washing process”
The produced colored particles are subjected to solid-liquid separation with a basket-type centrifuge “MARK III model number 60 × 40 (manufactured by Matsumoto Kikai Co., Ltd.)” to prepare a “colored particle 1” wet cake, and the wet cake is subjected to 40 ° C. The ion-exchanged water was added for washing. The solid-liquid separation and washing by the basket type centrifugal separator were repeated until the electric conductivity of the filtrate reached 5 μS / cm or less.

(8) "Drying process"
The wet cake prepared when the electrical conductivity of the filtrate was 5 μS / cm or less was crushed, and the water content was reduced to 0.5 mass% using “flash jet dryer (manufactured by Seishin Enterprise Co., Ltd.)”. Drying treatment was performed to obtain “colored particles 1” having a core-shell structure. The shell coverage on the “colored particle 1” surface was evaluated and found to be 98%.

(9) External Addition Treatment By adding the following external additives to the produced “colored particle 1” and performing external addition treatment with a Henschel mixer (made by Mitsui Miike Mining Co., Ltd.), “toner 1” having a core-shell structure is produced. did.

Silica treated with hexamethylsilazane (average primary particle size 12 nm)
0.6 part by mass n-octylsilane-treated titanium dioxide (average primary particle size 24 nm)
0.8 parts by mass The external addition treatment by the Henschel mixer was performed under the conditions of a peripheral speed of the stirring blade of 35 m / second, a treatment temperature of 35 ° C., and a treatment time of 15 minutes. By the above procedure, “toner 1” having a core-shell structure was produced.

1-2. Production of “Toners 2 to 10” In the “shelling step” in the production of “Toner 1”, 44 parts by mass (in terms of solid content) of “Shell-forming resin fine particles 1” was added, and magnesium chloride 6 An aqueous solution in which 30 parts by mass of hydrate was dissolved in 1000 parts by mass of ion-exchanged water was added over 3 minutes. Stirring was continued for 67 minutes after the addition, and “Toner 2” was produced by carrying out processing under the same conditions and procedures as the others. Further, 45 minutes after adding “shell forming resin fine particles 1”, the magnesium chloride hexahydrate aqueous solution was added over 3 minutes, and stirring was continued for 42 minutes after the addition. “Toner 3” was prepared by carrying out the process according to the procedure. Furthermore, 65 minutes after adding “shell forming resin fine particles 1”, the magnesium chloride hexahydrate aqueous solution was added over 3 minutes, and stirring was continued for 22 minutes after the addition. “Toner 4” was prepared by carrying out the process according to the procedure.

  In addition, after adding 72 minutes after adding “shell forming resin fine particles 1”, the magnesium chloride hexahydrate aqueous solution was added over 3 minutes, and stirring was continued for 15 minutes after the addition. “Toner 5” was prepared by carrying out the process according to the procedure. Further, after adding “shell forming resin fine particles 1” 10 minutes later, the magnesium chloride hexahydrate aqueous solution was added over 3 minutes, and stirring was continued for 77 minutes after the addition. “Toner 6” was prepared by carrying out the process according to the procedure. Furthermore, at the same time as the addition of “shell forming resin fine particles 1”, the magnesium chloride hexahydrate aqueous solution was added over 3 minutes, and stirring was continued for 87 minutes after the addition. As a result, “Toner 7” was produced.

  Also, in the “shelling step”, the “core 2” dispersion was used in place of the “core 1” dispersion, and 44 parts by mass (in terms of solid content) of “shell forming resin fine particles 1” were added thereto. After 45 minutes, an aqueous solution in which 35 parts by mass of magnesium sulfate heptahydrate was dissolved in 1000 parts by mass of ion-exchanged water was added over 3 minutes, and stirring was continued for 42 minutes to form a shell. Other than that, “Toner 8” was produced by carrying out the process under the same conditions and procedures as “Toner 1”. Further, in the production of “Toner 8”, instead of 35 parts by mass of magnesium sulfate heptahydrate, an aqueous solution in which 10 parts by mass of aluminum chloride hexahydrate was dissolved in 1000 parts by mass of ion-exchanged water was taken over 3 minutes. Except for the addition, the same procedure was followed to produce “Toner 9”. Further, in the production of “Toner 8”, after adding “shell forming resin fine particles 1” 10 minutes later, an aqueous solution obtained by dissolving 35 parts by mass of magnesium sulfate heptahydrate in 1000 parts by mass of ion-exchanged water 3 Added over a minute and continued stirring for 77 minutes to form a shell. Otherwise, “Toner 10” was prepared by carrying out the treatment under the same conditions and procedures. “Toners 2 to 10” were produced as described above. The production conditions of the produced “Toners 1 to 10” are shown in Table 1 below.

3. Evaluation experiment (1) Evaluation experiment 1 (Evaluation of storage performance)
For “Toners 1 to 10” produced by the above procedure, the toner aggregation rate was calculated by the following method, and the heat-resistant storage stability was evaluated. In addition, what used "toner 1-4, 8, 9" which formed the shell on the conditions which satisfy | fill the structure of this invention was made into "Examples 1-6", and a shell was used on the conditions which remove | deviate from the structure of this invention. The formed “Toners 5-7, 10” were used as “Comparative Examples 1-4”.

<Heat resistant storage>
0.5 g of the produced toner is put into a 10 ml glass bottle with an inner diameter of 21 mm, the lid is closed, shaken 600 times at room temperature with a tap denser KYT-2000 (manufactured by Seishin Enterprise), and then at 55 ° C. and 35 with the lid removed. It was left for 2 hours in an environment of% RH. Next, place the toner on a 48-mesh (mesh 350 μm) sieve, taking care not to crush the toner aggregates, set the powder tester (manufactured by Hosokawa Micron), and fix it with a press bar and knob nut. After adjusting the vibration strength to a feed width of 1 mm and applying vibration for 10 seconds, the ratio (mass%) of the amount of toner remaining on the sieve was measured.

  The toner aggregation rate is a value calculated by the following formula.

Toner aggregation rate (mass%)
= (Residual toner mass on sieve (g) /0.5 (g)) × 100
A toner aggregation rate of less than 15% by mass was determined to be acceptable, and a toner aggregation of less than 10% by mass was determined to have extremely good heat-resistant storage stability.

(2) Evaluation experiment 2 (Evaluation of low-temperature fixability)
The “toners 1 to 10” were mixed with a ferrite carrier having a volume average particle diameter of 60 μm coated with a silicone resin to prepare “two-component developers 1 to 10” with a toner concentration of 6%.

  Each of the produced “two-component developers 1 to 10” is filled in a developing device, and the developing device is mounted on a commercially available monochrome digital printer “bizhub Pro 1050 (manufactured by Konica Minolta Business Technologies, Inc.)”. Was evaluated. As the fixing device, the belt fixing type fixing device shown in FIG. 5 is used, and the surface temperature of the belt is changed as described later. The presence or absence of charge and the charge rising property were evaluated.

<Low temperature fixability>
The fixable temperature was calculated by the following procedure to evaluate the low temperature fixability. The fixable temperature is a fixing temperature at which the fixing rate is 90% or more.

Specifically, in a normal temperature and normal humidity (20 ° C., 50% RH) environment, the surface temperature of the fixing belt was changed from 100 to 160 ° C. in increments of 5 ° C., and a solid image of 2.5 cm square (toner adhesion amount 0). .3 mg / m ² ) print was produced. The fixing rate of each produced solid image was measured by a mending tape peeling method, a fixing temperature at which the fixing rate was 90% or more was determined, and the temperature was evaluated as a fixable temperature.

Hereinafter, the mending tape peeling method will be described.
(A) The absolute reflection density D ₀ of the toner image produced under the setting conditions where the toner adhesion amount of the solid black image of 2.5 cm square on the transfer paper is 0.3 mg / m ² is measured.
(B) “Mending tape (manufactured by Sumitomo 3M: No.810-3-12)” is lightly applied to the toner image.
(C) Rub the tape over 3.5 times with a pressure of 1 kPa.
(D) The tape is peeled off under the conditions of a peel angle of 180 ° and a peel strength of 2N.
(E) measuring the absolute reflection density _{D 1} of the post-peeling.
(F) from the absolute reflection density _{D 0} and _{D 1,} to calculate a retention rate. The fixing rate is the following formula: fixing rate (%) = (D ₁ / D ₀ ) × 100
It is calculated from. The absolute reflection density was measured using a reflection densitometer “RD-918 (manufactured by Macbeth)”. Those having a fixable temperature of less than 150 ° C. were accepted, and those having a fixable temperature of less than 130 ° C. were evaluated as excellent.

<Evaluation of density unevenness>
The image forming apparatus performs 3000 continuous prints in a room temperature and humidity environment (20 ° C., 50% RH), and halftone images on the 1000th, 2000th, and 3000th prints are printed. Visual observation was performed and evaluation was performed according to the following criteria. Only ◎ and ○ were accepted. That is,
◎: Halftone image with no density unevenness and uniform image ○: Halftone image has slight density unevenness but no problem in practical use ×: Halftone image has uneven density and practically problematic Level that becomes.

<Evaluation of charging start-up performance>
In a low-temperature and low-humidity environment (10 ° C, 20% RH), continuous printing of 3000 sheets per day is continued for 5 days, and a halftone image on the first printed material is visually observed to sweep over the image. The occurrence of streak-like image defects called was visually observed. The number of times image defects were confirmed in 5 days was evaluated, and a case where the occurrence of streak-like image defects was 2 times or less was regarded as acceptable.

  The results are shown in Table 2.

  As shown in Table 2, in “Examples 1 to 6” using a toner in which a shell is formed under the conditions satisfying the constituent requirements of the present invention, the toner aggregation rate is less than 15%, and the toner is used in a harsh environment. It was confirmed that the occurrence of blocking was not a concern even when stored. Good storage performance was obtained, and no contamination due to tacking was observed even when the toner images were rubbed with each other. Also, when continuous printing was performed, there was no problem in density unevenness or charge rise performance, and it was considered that satisfactory image formation performance and charge rise performance were obtained as a result of sufficient shell formation on the toner particle surface. It is done. On the other hand, in “Comparative Examples 1 to 4” using a toner having a shell formed under conditions deviating from the constituent requirements of the present invention, the toner aggregation rate as obtained in “Examples 1 to 6” cannot be obtained. It became difficult to store. In addition, density unevenness was likely to occur when continuous printing was performed, and stable charge rising performance could not be obtained. Thus, a clear difference in performance is seen between “Examples 1 to 6” and “Comparative Examples 1 to 4”. By forming the shell under conditions that satisfy the configuration of the present invention, a good core-shell structure is obtained. It was confirmed that a toner was obtained.

It is a schematic diagram explaining the polyvalent metal salt addition timing performed by this invention. FIG. 4 is a schematic diagram illustrating an example of a cross-sectional structure of a core-shell structured toner. 1 is a schematic view showing an example of a two-component development tandem type full-color image forming apparatus in which a toner produced in the present invention can be used. It is a schematic diagram showing an example of a fixing device using a heating roller. It is a schematic diagram showing an example of a belt fixing type fixing device.

Explanation of symbols

1 (1Y, 1M, 1C, 1K) photoconductor (electrostatic latent image carrier)
2 (2Y, 2M, 2C, 2K) Charging means 3 (3Y, 3M, 3C, 3K) Exposure means 4 (4Y, 4M, 4C, 4K) Developing means 5 (5Y, 5M, 5C, 5K, 5A) Transfer roll 6 (6Y, 6M, 6C, 6K) Cleaning device 7 Intermediate transfer member unit 10 (10Y, 10M, 10C, 10K) Image forming unit 24 Heat roll type fixing device 70 Intermediate transfer member A Core B Shell T Toner

Claims (3)

A method for producing a toner comprising a shelling step of adding a resin particle and a polyvalent metal salt to a core particle dispersion containing at least a resin and a colorant to form a shell on the surface of the core particle. ,
In the shelling step,
After the resin particles are added, the polyvalent metal salt is added during 15% to 70% of the time required for the shelling step. The toner manufacturing method according to claim 1, wherein the metal salt is magnesium chloride. The toner production method according to claim 1, wherein the toner has a glass transition temperature of 30 ° C. to 45 ° C.

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