Resin particle, toner, toner storage unit, developer, and image forming apparatus

Abstract

To provide a resin particle that has a small environmental load and can provide a toner excellent in charge stability and low temperature fixability.SOLUTION: A resin particle contains a binder resin and an organic compound having a sulfonic group, and has a core-shell structure. When the secondary ion intensity derived from the sulfonic group at t (nm) from the outermost surface of the surface of the resin particle is defined as I (t) in depth profile measurement of the surface of the resin particle by time-of-flight type secondary ion mass spectrometry, the following formulas (1) and (2) are satisfied within a range of 0<t<100. Formula (1) I(100)<I(t)<I(0). Formula (2) 0.005<I(100).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to resin particles, toner, a toner storage unit, a developer, and an image forming apparatus. [Background technology]

[0002] In recent years, from the viewpoint of reducing the burden on the environment, recycled toners have been studied, in which plant-derived resins or recycled polyethylene terephthalate are used as binder resins. However, in today's world where high speed is strongly required, there is a strong demand for recycled toner that is excellent in both charging stability and low temperature fixability.

[0003] Known technologies relating to various additives for improving the chargeability, durability, and storage stability of toners include a toner in which the structure of the charge control agent or the amount of charge control agent present in the toner matrix is ​​specified (see Patent Document 1), a toner in which the structural unit of a monomer containing either a sulfonic acid group or a sulfonate salt group is specified (see Patent Document 2), and a toner in which the surface acid value of a resin, which is a dispersion stabilizer on the matrix surface, is specified in order to control adhesion to the surface of the polyester resin (see Patent Document 3), and the like, and have achieved some degree of effectiveness. However, recycled toner requires further improvements in performance, and in particular, there is a demand for technology that allows for more precise control of the structure of the binder resin. Summary of the Invention [Problem to be solved by the invention]

[0004] If an organic compound having a sulfo group (hereinafter also referred to as "sulfo component") is present in excess, which affects charge stability, the viscoelasticity increases, sharp melting properties are suppressed, and low-temperature fixability is impaired. Therefore, in order to achieve both charge stability and low-temperature fixability of the toner, it is necessary to arrange the sulfo component in the base material at an appropriate gradient. In the present invention, both charge stability and low-temperature fixability are ensured by appropriately stacking the sulfo component.

[0005] In the conventional technology, the shell derived from sulfo was uniform, and it was difficult to control the arrangement of the sulfo component in the resin particles. The sulfo component should be laminated such that it is most present on the outermost surface of the core and gradually decreases from the outermost surface toward the inside with a certain gradient. If the amount of the sulfo component present at a depth of 100 nm from the outermost surface of the core is too small compared to the outermost surface of the core, or if the amount of the sulfo component present at a depth of 100 nm from the outermost surface of the core is more than the amount of the sulfo component present at a depth of 20 nm, the charge stability will decrease. <000G043>

[0006] An object of the present invention is to provide resin particles capable of obtaining toner with a small environmental load, excellent charge stability, and excellent low-temperature fixing property.

Means for Solving the Problem

[0007] The present invention is as described below. Resin particles having a core-shell structure, containing a binder resin and an organic compound having a sulfo group, In the depth profile measurement of the resin particle surface by time-of-flight secondary ion mass spectrometry, when the secondary ion intensity derived from the sulfo group at t (nm) from the outermost surface of the resin particle surface is defined as I (t), Resin particles characterized by satisfying the following formulas (1) and (2) in the range of 0 < t < 100. I (100) < I (t) < I (0) Formula (1) 0.005 < I (100) Formula (2)

Effect of the Invention

[0008] According to the present invention, the above-mentioned various problems in the prior art can be solved, and resin particles capable of obtaining toner with a small environmental load, excellent charge stability, and excellent low-temperature fixing property can be provided.

Brief Description of the Drawings

[0009] [Figure 1]FIG. 1 is a schematic diagram showing an example of an image forming apparatus according to the present invention. [Figure 2] FIG. 2 is a schematic diagram showing an example of a process cartridge according to the present invention. MODE FOR CARRYING OUT THE INVENTION

[0010] [Resin Particles] The resin particles of the present invention are resin particles containing matrix particles containing a binder resin and an organic compound having a sulfo group, and have the following configuration. In the depth profile measurement of the resin particle surface by time-of-flight secondary ion mass spectrometry, when the secondary ion intensity derived from the sulfo group at t (nm) from the outermost surface of the resin particle surface is I (t), In the range of 0 < t < 100, the resin particles are characterized by satisfying the following formulas (1) and (2). I(100) < I(t) < I(0) Formula (1) 0.005 < I(100) Formula (2) The above formula (1) means that the sulfo component is most present on the outermost surface of the resin particles, and the above formula (2) means that a sulfo component of a certain level or more is present in a region close to the center away from the resin particle surface.

[0011] Further, the resin particles of the present invention have a core-shell structure in which a shell layer adheres to the surface of the core layer. In this case, the emulsion aggregation method is optimal as a method for producing resin particles in which a shell derived from a sulfo component is laminated on the core surface in an arbitrary gradient. This is because it is easy to control the lamination gradient in the shell film such as the compatibility parameters of the core and the shell and the aggregation and fusion temperatures. Hereinafter, the "resin particles" may be referred to as "toner" or "toner particles".

[0012] An example of an organic compound having a sulfo group is a sulfonic acid group-containing copolymer. The vinyl aromatic hydrocarbon used in the production of the sulfonic acid group-containing copolymer is a compound (monomer) having a structure in which a vinyl group is bonded to an aromatic hydrocarbon. Specific examples include styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, 2-propylstyrene, 3-propylstyrene, 4-propylstyrene, 2-isopropylstyrene, 3-isopropylstyrene, 4-isopropylstyrene, 2-chlorostyrene, 3-chlorostyrene, 4-chlorostyrene, 2-methyl-α-methylstyrene, 3-methyl-α-methylstyrene, 4-methyl-α-methylstyrene, 2-ethyl-α-methylstyrene, 3-ethyl-α-methylstyrene, 4-ethyl-α-methylstyrene, 2-propyl-α-methylstyrene, 3-propyl-α-methylstyrene, 4-propyl-α-methylstyrene, 2-isopropyl-α-methylstyrene, 3-isopropyl propyl-α-methylstyrene, 4-isopropyl-α-methylstyrene, 2-chloro-α-methylstyrene, 3-chloro-α-methylstyrene, 4-chloro-α-methylstyrene, 2,3-dimethylstyrene, 3,4-dimethylstyrene, 2,4-dimethylstyrene, 2,6-dimethylstyrene, 2,3-diethylstyrene, 3,4-diethylstyrene, 2,4-diethylstyrene, 2,6-diethylstyrene, 2-methyl-3-ethylstyrene, 2-methyl-4-ethylstyrene, 2-chloro-4-methylstyrene Examples of vinyl aromatic hydrocarbons include styrene, 2,3-dimethyl-α-methylstyrene, 3,4-dimethyl-α-methylstyrene, 2,4-dimethyl-α-methylstyrene, 2,6-dimethyl-α-methylstyrene, 2,3-diethyl-α-methylstyrene, 3,4-diethyl-α-methylstyrene, 2,4-diethyl-α-methylstyrene, 2,6-diethyl-α-methylstyrene, 2-ethyl-3-methyl-α-methylstyrene, 2-methyl-4-propyl-α-methylstyrene, and 2-chloro-4-ethyl-α-methylstyrene. These vinyl aromatic hydrocarbons can be used either alone or in combination of two or more.

[0013] <Core-shell structure> The resin particles have a core-shell structure consisting of a core layer and a shell layer. The shell resin constituting the shell layer is preferably amorphous polyester resin A described below, and the amorphous polyester resin contained in the core layer is preferably amorphous polyester resin B described below. The shell layer preferably contains an organic compound having a sulfo group.

[0014] (Amorphous polyester resin A) A linear polyester resin is preferred, and an unmodified polyester resin is also preferred, as the amorphous polyester resin A. The amorphous polyester resin A is a polyester resin soluble in tetrahydrofuran (THF) and chloroform. The unmodified polyester resin is a polyester resin obtained using a polyhydric alcohol and a polycarboxylic acid or a derivative thereof, and is a polyester resin that has not been modified with an isocyanate compound or the like.

[0015] (Amorphous polyester resin B) A linear polyester resin is preferred, and an unmodified polyester resin is also preferred, as the amorphous polyester resin B. The amorphous polyester resin B is a polyester resin soluble in tetrahydrofuran (THF) and chloroform. It is preferable that the amorphous polyester resin B does not contain a urethane bond or a urea bond. By using a plant-derived component or a component derived from recycled resin in at least one of the polyhydric alcohol and the polycarboxylic acid or a derivative thereof, the amorphous polyester resin B can be an environmentally friendly component.

[0016] [Method of manufacturing resin particles] The resin particles of the present invention can be produced, for example, by the following emulsion polymerization aggregation method. a. Oil phase preparation process: A process for preparing an oil phase by dissolving or dispersing binder resin, colorant, crosslinking component, wax, etc. in an organic solvent. b. Phase inversion emulsification step: A step of adding water to the oil phase to invert the phase from a water-in-oil dispersion to an oil-in-water dispersion c. Solvent removal step: a step of removing the organic solvent from the oil-in-water dispersion to obtain a fine particle dispersion. d. Aggregation step: a step of aggregating the fine particles in the fine particle dispersion to obtain aggregated particles e.: A step of forming a shell on the surface of the aggregated particles f.: A step of fusing the shell-forming aggregated particles g.: Annealing the fused aggregated particles as needed h.: ​​Particle washing and drying process Each of the above steps and the materials used in each step will be described below.

[0017] <Oil phase preparation process> First, an oil phase is prepared by dissolving or dispersing a binder resin, a colorant, a crosslinking component, a wax, etc. in an organic solvent. The oil phase can be prepared by gradually adding the binder resin, the colorant, etc. to an organic solvent while stirring, and dissolving or dispersing them. Known dispersing devices can be used, for example, a dispersing machine such as a bead mill or a disk mill. The materials used in the oil phase preparation step will be described below.

[0018] <Binder resin> As the binder resin, the above-mentioned amorphous polyester resin B can be used, and amorphous polyester resins that are advantageous for low-temperature fixing are preferred, and linear polyester resins are particularly preferred, with unmodified polyester resins being more preferred.

[0019] The unmodified polyester resin is a polyester resin obtained using a polyhydric alcohol and a polycarboxylic acid or a derivative thereof, such as a polycarboxylic acid, a polycarboxylic acid anhydride, or a polycarboxylic acid ester, and is not modified with an isocyanate compound or the like.

[0020] The amorphous polyester resin preferably does not contain a urethane bond or a urea bond. The amorphous polyester resin preferably contains a dicarboxylic acid component as a constituent, and the dicarboxylic acid component preferably contains 50 mol % or more of terephthalic acid. This is advantageous in terms of heat-resistant storage stability.

[0021] The amorphous polyester resin used in the present invention is preferably a biomass-derived resin synthesized using plant-derived monomers, preferably propylene glycol as the plant-derived alcohol monomer and terephthalic acid or succinic acid as the acid component. There are no particular limitations on these, and there are no limitations as long as the component is derived from a plant.

[0022] In the present invention, it is preferable to use a recycled resin as the binder resin. The recycled resin used in this invention is made by processing recycled materials, such as PET (polyethylene terephthalate) and PBT (polybutylene terephthalate), into flakes. These materials have a weight-average molecular weight (Mw) of approximately 30,000 to 100,000. However, there are no restrictions on the molecular weight distribution, composition, manufacturing method, or form of use of the PET and PBT. Furthermore, recycled materials are not required; off-specification fiber waste or pellets can also be used. By adjusting the ratio of recycled PET used during polyester resin synthesis, the environmental friendliness and toner quality can be adjusted.

[0023] Examples of the polyhydric alcohol include diols. Examples of the diol include alkylene (carbon number 2 to 3) oxide (average number of added moles 1 to 10) adducts of bisphenol A such as polyoxypropylene(2.2)-2,2-bis(4-hydroxyphenyl)propane and polyoxyethylene(2.2)-2,2-bis(4-hydroxyphenyl)propane; ethylene glycol, propylene glycol; hydrogenated bisphenol A, and alkylene (carbon number 2 to 3) oxide (average number of added moles 1 to 10) adducts of hydrogenated bisphenol A. These may be used alone or in combination of two or more.

[0024] Examples of the polycarboxylic acid include dicarboxylic acids. Examples of the dicarboxylic acid include adipic acid, phthalic acid, isophthalic acid, terephthalic acid, fumaric acid, maleic acid; and succinic acids substituted with an alkyl group having 1 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms, such as dodecenylsuccinic acid and octylsuccinic acid.

[0025] Among these, succinic acid, a saturated aliphatic acid derived from plants, is preferred. Being plant-derived can enhance carbon neutrality. Saturated aliphatic groups have the effect of enhancing the recrystallization properties of crystalline polyester resins, increasing the aspect ratio of the crystalline polyester resins and improving low-temperature fixability. These may be used alone or in combination of two or more.

[0026] Furthermore, for the purpose of adjusting the acid value and hydroxyl value, the amorphous polyester resin B may contain at least one of a trivalent or higher carboxylic acid and a trivalent or higher alcohol at the end of the resin chain. Examples of the trivalent or higher carboxylic acid include trimellitic acid, pyromellitic acid, and acid anhydrides thereof. Examples of the trihydric or higher alcohol include glycerin, pentaerythritol, and trimethylolpropane.

[0027] The molecular weight of the amorphous polyester resin B is not particularly limited and can be appropriately selected depending on the purpose. As measured by GPC (gel permeation chromatography), the weight average molecular weight (Mw) is preferably 3,000 or more and 10,000 or less. The number average molecular weight (Mn) is preferably 1,000 or more and 4,000 or less. The Mw / Mn ratio is preferably 1.0 to 4.0.

[0028] When the molecular weight is equal to or greater than the lower limit, it is possible to prevent the toner from decreasing in heat-resistant storage stability and durability against stress such as stirring in a developing machine. When the molecular weight is equal to or less than the upper limit, the viscoelasticity of the toner when melted can be prevented from increasing, and the low-temperature fixability can be prevented from decreasing.

[0029] The weight average molecular weight (Mw) is more preferably 4,000 or more and 7,000 or less. The number average molecular weight (Mn) is more preferably 1,500 or more and 3,000 or less. The Mw / Mn ratio is more preferably 1.0 or more and 3.5 or less.

[0030] The acid value of the amorphous polyester resin B is not particularly limited and can be appropriately selected depending on the purpose. It is preferably 1 mgKOH / g or more and 50 mgKOH / g or less, and more preferably 5 mgKOH / g or more and 30 mgKOH / g or less. When the acid value is 1 mgKOH / g or more, the toner tends to be negatively charged, and further, when fixed to paper, the affinity between the paper and the toner is improved, thereby improving low-temperature fixability. When the acid value is 50 mgKOH / g or less, it is possible to suppress a decrease in charging stability, particularly charging stability against environmental fluctuations. The hydroxyl value of the amorphous polyester resin B is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 5 mgKOH / g or more.

[0031] The glass transition temperature (Tg) of the amorphous polyester resin B is preferably 40° C. or higher and 80° C. or lower, more preferably 50° C. or higher and 70° C. or lower. When the glass transition temperature is 40° C. or higher, the toner has sufficient heat-resistant storage stability and durability against stress such as stirring in a developing machine, and also has good filming resistance. When the glass transition temperature is 80° C. or lower, the toner is sufficiently resistant to deformation due to heat and pressure during fixation, The low-temperature fixability is improved.

[0032] The molecular structure of the amorphous polyester resin B can be confirmed by NMR measurement using a solution or a solid, as well as by X-ray diffraction, GC / MS, LC / MS, IR measurement, etc. -1 and 990±10cm -1 One method is to detect amorphous polyester resins that do not have absorption due to olefin δCH (out-of-plane bending vibration).

[0033] The content of the amorphous polyester resin B is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 50 to 90 parts by weight, and more preferably 60 to 80 parts by weight, relative to 100 parts by weight of the toner. When the content is 50 parts by weight or more, the dispersibility of the pigment and release agent in the toner can be prevented from deteriorating, and the occurrence of image fogging and distortion can be suppressed. When the content is 90 parts by weight or less, the contents of the crystalline polyester resin C and amorphous polyester resin A can be prevented from decreasing, and a decrease in low-temperature fixability can be suppressed. When the content is within the above-mentioned more preferred range, it is advantageous in that both high image quality and low-temperature fixability are excellent.

[0034] (shell resin) The shell resin is preferably the amorphous polyester resin B, and preferably does not contain plant-derived materials. Alternatively, the amorphous polyester resin A may be an organic compound having a sulfo group. Examples of polyhydric alcohols include diols. Examples of diols include alkylene (carbon number 2-3) oxide (average number of added moles 1-10) adducts of bisphenol A, such as polyoxypropylene (2.2)-2,2-bis(4-hydroxyphenyl)propane and polyoxyethylene (2.2)-2,2-bis(4-hydroxyphenyl)propane; hydrogenated bisphenol A; and alkylene (carbon number 2-3) oxide (average number of added moles 1-10) adducts of hydrogenated bisphenol A. These may be used alone or in combination of two or more. Examples of polycarboxylic acids include dicarboxylic acids, such as adipic acid, phthalic acid, isophthalic acid, terephthalic acid, fumaric acid, and maleic acid. Furthermore, examples of components containing a sulfo group include sodium 5-sulfoisophthalate.

[0035] (crystalline resin) It is preferable to add a crystalline resin to the toner of the present invention in order to improve low-temperature fixability. The crystalline resin may be added to either the core layer or the shell layer, but is preferably added to the core layer. The crystalline resin is not particularly limited as long as it has crystallinity, and can be appropriately selected according to the purpose. For example, polyester resin, polyurethane resin, polyurea resin, polyamide resin, polyether resin, vinyl resin, modified crystalline resin, etc. can be mentioned. These may be used alone or in combination of two or more. The crystalline polyester will be explained below.

[0036] (crystalline polyester resin) Crystalline polyester resins are obtained from polyhydric alcohols and polycarboxylic acids such as polycarboxylic acids, polycarboxylic anhydrides, and polycarboxylic esters, or derivatives thereof. Note that, in the present invention, the crystalline polyester resin refers to a resin obtained using a polyhydric alcohol and a polycarboxylic acid such as polycarboxylic acids, polycarboxylic anhydrides, and polycarboxylic esters, or derivatives thereof, as described above, and modified polyester resins, such as prepolymers and resins obtained by subjecting the prepolymers to crosslinking and / or elongation reactions, do not fall under the category of crystalline polyester resins.

[0037] <<Polyhydric alcohol>> The polyhydric alcohol is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include diols and trihydric or higher alcohols. Examples of the diol include saturated aliphatic diols. Examples of the saturated aliphatic diol include linear saturated aliphatic diols and branched saturated aliphatic diols. Among these, linear saturated aliphatic diols are preferred, and linear saturated aliphatic diols having 2 to 12 carbon atoms are more preferred. If the saturated aliphatic diol is branched, the crystallinity of the crystalline polyester resin may decrease, resulting in a lower melting point. Furthermore, if the saturated aliphatic diol has more than 12 carbon atoms, it may be difficult to obtain a practical material.

[0038] Examples of the saturated aliphatic diol include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, 1,14-eicosanedecanediol, etc. Among these, ethylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, and 1,12-dodecanediol are preferred in terms of the high crystallinity and excellent sharp melt properties of the crystalline polyester resin. Examples of the trihydric or higher alcohol include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, etc. These may be used alone or in combination of two or more.

[0039] <<Polycarboxylic Acids>> The polycarboxylic acid is not particularly limited and can be appropriately selected depending on the purpose. Examples include dicarboxylic acids and tricarboxylic or higher carboxylic acids. Examples of the dicarboxylic acid include saturated aliphatic dicarboxylic acids such as oxalic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, and 1,18-octadecanedicarboxylic acid; and aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, naphthalene-2,6-dicarboxylic acid, malonic acid, and mesaconic acid. Further examples include anhydrides of these compounds and lower (C1 to C3) alkyl esters of these compounds. Among these, plant-derived saturated aliphatic fatty acids having 12 or less carbon atoms are preferred from the viewpoint of carbon neutrality.

[0040] Examples of the trivalent or higher carboxylic acid include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, etc., as well as anhydrides thereof and lower (C1 to C3) alkyl esters thereof, etc. These may be used alone or in combination of two or more.

[0041] The crystalline polyester resin is preferably composed of a linear saturated aliphatic dicarboxylic acid having 4 to 12 carbon atoms and a linear saturated aliphatic diol having 2 to 12 carbon atoms. This results in high crystallinity and excellent sharp melting properties, allowing for excellent low-temperature fixability. One method for controlling the crystallinity and softening point of the crystalline polyester resin is to design and use a non-linear polyester obtained by condensation polymerization of a trivalent or higher polyhydric alcohol such as glycerin as the alcohol component or a trivalent or higher polycarboxylic acid such as trimellitic anhydride as the acid component during polyester synthesis.

[0042] The molecular structure of the crystalline polyester resin of the present invention can be confirmed by NMR measurement of a solution or a solid, as well as X-ray diffraction, GC / MS, LC / MS, IR measurement, etc., but it can be easily confirmed by infrared absorption spectroscopy at 965±10 cm -1 Or 990±10cm -1 Examples include those that have absorption based on the δCH (out-of-plane bending vibration) of olefins.

[0043] Regarding the molecular weight, from the viewpoint that those with a sharp molecular weight distribution and a low molecular weight have excellent low-temperature fixability, and that a large amount of low-molecular-weight components deteriorates heat-resistant storage stability, extensive research has revealed that, in the molecular weight distribution by GPC of the o-dichlorobenzene soluble fraction, the peak position in a molecular weight distribution diagram with the horizontal axis being log(M) and the vertical axis being weight % is in the range of 3.5 to 4.0, the half-width of the peak is 1.5 or less, the weight average molecular weight (Mw) is 3,000 to 30,000, the number average molecular weight (Mn) is 1,000 to 10,000, and Mw / Mn is 1 to 10. It is further preferred that the weight average molecular weight (Mw) is 5,000 to 15,000, the number average molecular weight (Mn) is 2,000 to 10,000, and Mw / Mn is 1-5.

[0044] From the viewpoint of affinity between paper and resin, the acid value of the crystalline polyester resin is preferably 5 mgKOH / g or more to achieve the desired low-temperature fixability, and more preferably 7 mgKOH / g or more to prepare fine particles by phase inversion emulsification, while 45 mgKOH / g or less is preferred to improve hot offset resistance. Furthermore, the hydroxyl value of the crystalline polymer is preferably 0 mgKOH / g or more and 50 mgKOH / g or less, more preferably 5 mgKOH / g or more and 50 mgKOH / g or less, to achieve the desired low-temperature fixability and good charging characteristics.

[0045] (coloring agent) Known dyes and pigments can be used as colorants, for example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, ochre, yellow lead, titanium yellow, polyazo yellow, oil yellow, Hansa yellow (GR, A, RN, R), pigment yellow L, benzidine yellow (G, GR), permanent yellow (NCG), Balkan fast yellow (5G, R), tartrazine lake, quinoline yellow lake, anthrazan yellow BGL, isoindolinone yellow -, red iron oxide, red lead, vermilion lead, cadmium red, cadmium mercury red, antimony vermilion, permanent red 4R, para red, faise red, parachlor orthonitroaniline red, Lithol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmine BS, permanent red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belcan Fast Rubin B, Brilliant Scarlet G, Lithol Rubin GX, permanent red F5R, Brilliant Carmine 6B, POG Mentos Scarlet 3B, Bordeaux 5B, Toluidine Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thioindigo Red B, Thioindigo Maroon, Oil Red, Quinacridone Red, Pyrazolone Red, Polyazo Red, Chrome Vermilion, Benzidine Orange, Perinone Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkaline Blue Lake, Peacock Blue Lake, Victoria Blue Lake, Metal-free Phthalocyanine Blue, Phthalocyanine Blue, Fast Sky Blue, Indanthrene Blue (RS, BC), Indigo, Ultramarine, Prussian Blue, Anthraquinone Blue, Fast Violet B, Methyl Violet Lake, Cobalt Purple, Manganese Purple, Dioxane Violet, Anthraquinone Violet, Chrome Green, Zinc Green, Chromium Oxide, Pyridian, Emerald Green, Pigment Green B, Naphthol Green B, Green Gold, Acid Green Lake, Malachite Green Lake,Phthalocyanine green, anthraquinone green, titanium oxide, zinc oxide, lithopone, and mixtures thereof can be used.

[0046] (organic solvent) The organic solvent is preferably volatile and has a boiling point of less than 100°C, which facilitates subsequent removal of the organic solvent. Examples of such organic solvents include toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, ethyl acetate, methyl ethyl ketone, methyl isobutyl ketone, methanol, ethanol, and isopropyl alcohol, which can be used alone or in combination. When the resin to be dissolved or dispersed in the organic solvent is a resin having a polyester skeleton, it is preferable to use an ester-based solvent such as methyl acetate, ethyl acetate, or butyl acetate, or a ketone-based solvent such as methyl ethyl ketone or methyl isobutyl ketone, as these solvents have high solubility. Among these, methyl acetate, ethyl acetate, and methyl ethyl ketone are particularly preferred, as they are easy to remove from the solvent. A charge control agent or the like may be added to the oil phase.

[0047] (Charge control agent) Any known charge control agent can be used, such as nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxyamines, quaternary ammonium salts (including fluorine-modified quaternary ammonium salts), alkylamides, phosphorus simple substance or compounds, tungsten simple substance or compounds, fluorine-based activators, metal salicylate, and metal salts of salicylic acid derivatives. Specifically, these include the nigrosine dye Bontron 03, the quaternary ammonium salt Bontron P-51, the metal-containing azo dye Bontron S-34, the oxynaphthoic acid metal complex E-82, the salicylic acid metal complex E-84, and the phenol condensate E-89 (all manufactured by Orient Chemical Industry Co., Ltd.), the quaternary ammonium salt molybdenum complexes TP-302 and TP-415 (both manufactured by Hodogaya Chemical Co., Ltd.), the quaternary ammonium salt Copy Charge PSY VP2038, the triphenylmethane derivative Copy Blue PR, and the quaternary ammonium salt Copy Charge NEG VP2036 and Copy Charge NX. Examples of suitable charge control agents include VP434 (manufactured by Hoechst), LRA-901, the boron complex LR-147 (manufactured by Nippon Carlit), copper phthalocyanine, perylene, quinacridone, azo pigments, and other polymeric compounds having functional groups such as sulfonic acid groups, carboxyl groups, and quaternary ammonium salts. The charge control agent may be used in an amount that allows the agent to exhibit its performance without interfering with fixability, etc., and is contained in the toner in an amount of 0.5 to 5% by mass, and preferably 0.8 to 3% by mass.

[0048] (wax) The wax is not particularly limited and can be appropriately selected depending on the purpose, but a low-melting release agent with a melting point of 50° C. to 120° C. is preferred. The low-melting release agent, when dispersed in the resin, effectively acts as a release agent between the fixing roller and the toner interface, thereby improving hot offset resistance even in an oil-less system (where a release agent such as oil is not applied to the fixing roller).

[0049] Suitable examples of release agents include waxes. Examples of waxes include natural waxes such as plant-based waxes (e.g., carnauba wax, cotton wax, Japan wax, and rice wax); animal-based waxes (e.g., beeswax and lanolin); mineral waxes (e.g., ozokerite and cerusine); and petroleum waxes (e.g., paraffin, microcrystalline wax, and petrolatum). In addition to these natural waxes, synthetic hydrocarbon waxes (e.g., Fischer-Tropsch wax and polyethylene wax); synthetic waxes (e.g., esters, ketones, and ethers); and other synthetic waxes. Other examples include fatty acid amides (e.g., 12-hydroxystearic acid amide, stearic acid amide, phthalimide anhydride, and chlorinated hydrocarbons); low-molecular-weight crystalline polymer resins (e.g., polyacrylate homopolymers or copolymers such as poly-n-stearyl methacrylate and poly-n-lauryl methacrylate) (e.g., n-stearyl acrylate-ethyl methacrylate copolymers); and crystalline polymers having long alkyl groups in their side chains. These may be used alone or in combination of two or more.

[0050] From the viewpoint of carbon neutrality, vegetable waxes are preferred. The melting point of the wax is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 50°C to 120°C, more preferably 60°C to 90°C. A melting point of 50°C or higher can prevent the wax from adversely affecting heat-resistant storage stability, while a melting point of 120°C or lower can effectively prevent the problem of cold offset during low-temperature fixing. The melt viscosity of the wax, measured at a temperature 20°C higher than the melting point of the wax, is preferably 5 cps to 1,000 cps, more preferably 10 cps to 100 cps. A melt viscosity of 5 cps or higher can prevent a decrease in release properties, while a melt viscosity of 1,000 cps or lower can fully exhibit the effects of hot offset resistance and low-temperature fixability. The wax content in the toner is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 0% to 40% by mass, more preferably 3% to 30% by mass. A content of 40% by mass or lower can prevent a decrease in toner fluidity.

[0051] <Phase inversion emulsification process> Next, the oil phase obtained in the oil phase preparation step is subjected to phase inversion emulsification. In the present invention, the oil phase is neutralized with an alkali such as sodium hydroxide or aqueous ammonia, and then Ion-exchanged water is added to the mixture, and the water-in-oil dispersion is inverted to an oil-in-water dispersion by phase inversion emulsification.

[0052] <Solvent removal process> To remove the organic solvent from the resulting oil-in-water dispersion, a method can be employed in which the temperature of the entire system is gradually increased while being stirred, and the organic solvent in the droplets is completely evaporated and removed. Alternatively, the obtained oil-in-water dispersion can be sprayed into a dry atmosphere while stirring to completely remove the organic solvent from the droplets. Alternatively, the oil-in-water dispersion can be depressurized while stirring to evaporate and remove the organic solvent. The latter two methods can be used in combination with the first method.

[0053] The drying atmosphere into which the oil-in-water dispersion is sprayed generally includes air, nitrogen, carbon dioxide, heated combustion gas, etc., and in particular, various air streams heated to a temperature equal to or higher than the boiling point of the highest boiling point solvent used. The desired quality can be obtained sufficiently by short-term treatment using a belt dryer, rotary kiln, etc. By the above method, a colored particle dispersion can be obtained.

[0054] <Agglomeration process> Next, the resulting colored particle dispersion is agitated to aggregate until the desired particle size is reached. To aggregate, existing methods such as adding a flocculant or adjusting the pH can be used. When adding a flocculant, it may be added directly, but it is preferable to use an aqueous solution of the flocculant, as this can prevent localized high concentrations. It is also preferable to add the flocculant gradually while monitoring the particle size of the flocculated particles. The temperature of the dispersion during aggregation is preferably near the Tg of the resin used. If the liquid temperature is too low, aggregation does not proceed very well, resulting in poor efficiency, while if the liquid temperature is too high, the aggregation rate increases, resulting in the generation of coarse particles and a deterioration in particle size distribution. When the target particle size is reached, aggregation is stopped by adding a salt or chelating agent with a low ionic valence, adjusting the pH, lowering the temperature of the dispersion, or adding a large amount of aqueous medium to dilute the concentration. By the above method, a dispersion of aggregated particles can be obtained.

[0055] In the aggregation step, a wax may be added as a release agent, or a crystalline resin may be added to improve low-temperature fixability. In this case, a dispersion of wax dispersed in an aqueous medium or a dispersion of a crystalline resin may be prepared, and these may be mixed with the fine particle dispersion and then aggregated to obtain aggregated particles in which the wax or crystalline resin is uniformly dispersed. The flocculant will be explained below.

[0056] (flocculant) Known flocculants can be used, such as metal salts of monovalent metals such as sodium and potassium, metal salts of divalent metals such as calcium and magnesium, and metal salts of trivalent metals such as iron and aluminum.

[0057] <Shelling process> The shell forming step is a step of forming a shell layer on the aggregated particles obtained in the aggregation step. The method for forming the shell layer is not particularly limited and can be appropriately selected depending on the purpose. For example, there is a method in which spherical particles having a desired particle size are produced in the fusion step, the shell resin is added, and the aggregation step and the fusion step described below are repeated to form a shell layer.

[0058] <Fusing process> The resulting aggregated particles are then fused by heat treatment to reduce irregularities and to form spherical particles. Fusion can be achieved by heating the dispersion of the colored aggregated particles while stirring. The temperature of the dispersion is preferably near a temperature above the Tg of the resin used.

[0059] <Cleaning and drying process> The toner particle dispersion obtained by the above method contains sub-materials such as aggregating salts in addition to the toner particles, so washing is carried out to extract only the toner particles from the dispersion. Methods for washing toner particles include centrifugal separation, vacuum filtration, and filter press, but are not particularly limited in the present invention. Either method will yield a cake of toner particles, but if the toner particles cannot be sufficiently washed in one operation, the obtained cake may be dispersed again in an aqueous solvent to form a slurry, and the process of extracting the toner particles by either of the above methods may be repeated. Alternatively, if washing is performed by vacuum filtration or filter press, a method may be adopted in which the aqueous solvent is passed through the cake to wash away the secondary materials that are engulfed in the colored resin particles. The aqueous solvent used for this washing is water or a mixed solvent of water and an alcohol such as methanol or ethanol, but considering the cost and the environmental load due to wastewater treatment, it is preferable to use water.

[0060] Since the washed toner particles contain a large amount of the aqueous medium, only the toner particles can be obtained by removing the aqueous medium through drying. As a drying method, a dryer such as a spray dryer, a vacuum freeze dryer, a reduced pressure dryer, a stationary shelf dryer, a movable shelf dryer, a fluidized bed dryer, a rotary dryer, an agitator dryer, etc. It is preferable that the dried toner particles are finally dried until the moisture content is less than 1%. Furthermore, if the colored resin particles after drying are in the form of soft agglomerates and cause inconvenience during use, they may be crushed using a device such as a jet mill, a Henschel mixer, a super mixer, a coffee mill, an Oster blender, or a food processor to loosen the soft agglomerates.

[0061] (Annealing process) In particular, when a crystalline resin is added, annealing after fusion causes phase separation between the amorphous resin and the crystalline resin, improving fixability. Specifically, this can be achieved by storing the toner at a temperature near its Tg for 10 hours or more.

[0062] (External addition process) Toner particles obtained in the present invention may be added or mixed with inorganic fine particles, polymeric fine particles, cleaning aids, etc. in order to provide them with fluidity, chargeability, cleaning properties, etc. Specific mixing methods include applying an impact force to the mixture with blades rotating at high speed, or throwing the mixture into a high-speed air current, accelerating it, and causing the particles or composite particles to collide with an appropriate collision plate. Examples of equipment include an Ang Mill (manufactured by Hosokawa Micron Corporation), a modified I-type Mill (manufactured by Nippon Pneumatic Co., Ltd.) with reduced grinding air pressure, a Hybridization System (manufactured by Nara Machinery Works), a Kryptron System (manufactured by Kawasaki Heavy Industries, Ltd.), and an automatic mortar.

[0063] (external additives) The primary particle diameter of the inorganic fine particles is preferably 5 nm or more and 2 μm or less, and more preferably 5 nm or more and 500 nm or less. 2 / g or more 500m 2 The proportion of the inorganic fine particles used is preferably 0.01% by mass or more and 5% by mass or less of the toner.

[0064] Specific examples of inorganic fine particles include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, chromium oxide, cerium oxide, penguin, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride.

[0065] Examples of polymeric fine particles include polymer particles made of polystyrene, methacrylate ester or acrylate ester copolymers obtained by soap-free emulsion polymerization, suspension polymerization, or dispersion polymerization, polycondensation systems such as silicone, benzoguanamine, or nylon, and thermosetting resins.

[0066] Such fluidizing agents can be surface-treated to increase their hydrophobicity and prevent deterioration of flow properties and charging properties even under high humidity. Examples of preferred surface treatment agents include silane coupling agents, silylating agents, silane coupling agents having a fluorinated alkyl group, organic titanate coupling agents, aluminum coupling agents, silicone oils, and modified silicone oils.

[0067] Examples of cleaning improvers for removing the developer remaining on the photosensitive member or primary transfer medium after transfer include fatty acid metal salts such as zinc stearate, calcium stearate, and stearic acid, and polymer fine particles produced by soap-free emulsion polymerization of, for example, polymethyl methacrylate fine particles, polystyrene fine particles, etc. The polymer fine particles preferably have a relatively narrow particle size distribution and a volume average particle size of 0.01 to 1 μm.

[0068] [Measurement method] In the present invention, "depth profile measurement of the resin particle surface by time-of-flight secondary ion mass spectrometry" is defined as the following measurement. <Depth profile evaluation> The negative ion depth profile of the pelletized resin particles was measured using a time-of-flight secondary ion mass spectrometer (abbreviated as ToF-SIMS: model name: TOF-SIMS IV manufactured by ION-TOF) under the following conditions. Primary ion: Bi 3++ ,Accelerating voltage 30kV, probe current 0.2pA, 150um square scanning Secondary ions: negative ions collected, 4 scans / cycle integration Sputtering: Ar+, accelerating voltage 2kV, probe current 50nA, 40sec / cycle SO3 at the sputtering time t seconds obtained (-) The secondary ion intensity I(t) was determined. The sputtering rate is calculated using a standard sample. The relationship between sputtering time and depth is that a PMMA film can be removed by 30 nm in 100 seconds. This sputtering rate is converted into depth from the sputtering time on the horizontal axis of the depth profile.

[0069] (Separation of toner base particles from toner) The above measurement can also be carried out using toner base particles from which additives have been removed as follows. Add 5.00 g of surfactant and 300 mL of distilled water to a 500 mL beaker and dissolve. Then, dilute to 1,000 mL to obtain a surfactant solution. As the surfactant, Drywell (manufactured by Fujifilm Corporation) is used. 3.75 g of toner is added to 50 mL of this surfactant solution and dispersed uniformly. This toner dispersion is irradiated with ultrasonic waves for 100 seconds using an ultrasonic homogenizer (trade name: homogenizer, model VCX750, CV33, manufactured by SONICS & MATERIALS) at a frequency of 20 kHz and an output of 40 W. The amount of energy applied at this time is calculated from the product of the output and the irradiation time (40W x 100 seconds = 4kJ). At this time, the toner dispersion is cooled as needed so that the temperature does not rise above 40°C. The obtained dispersion is suction filtered using filter paper (product name: Qualitative Filter Paper (No. 2, 110 mm), manufactured by Advantec Toyo Co., Ltd.), washed twice again with ion-exchanged water, filtered under reduced pressure to remove any free additives, and then dried in a dryer for at least 1 hour to obtain toner base particles as a sample for measurement. This operation is carried out multiple times to obtain the required amount.

[0070] (Developer storage unit) The developer containing unit in the present invention refers to a unit that contains developer in a unit having a function of containing developer. The developer accommodating unit may be in the form of a developer container, a developing device, or a process cartridge. The developer container refers to a container that contains a developer. The developing device is a device that contains a developer and has a means for developing. The process cartridge is a unit that integrates at least an image carrier and a developing unit and is detachable from an image forming apparatus. At least one of a charging unit, an exposing unit, and a cleaning unit may be integrated with the image carrier and the developing unit.

[0071] (Image forming device) Next, one embodiment of a method for forming an image using the image forming apparatus of the present invention will be described with reference to Fig. 1. Although a printer is shown as an example of the image forming apparatus of this embodiment, the image forming apparatus is not particularly limited as long as it is capable of forming an image using toner in a copier, facsimile, multifunction machine, or the like. The image forming apparatus 200 includes a paper feed section 210 , a conveying section 220 , an image forming section 230 , a transfer section 240 , and a fixing unit 250 . The paper feed section 210 includes a paper feed cassette 211 in which the paper P to be fed is stacked, and a paper feed roller 212 that feeds the paper P stacked in the paper feed cassette 211 one sheet at a time.

[0072] The conveying section 220 includes a roller 221 that conveys the paper P fed by the paper feed roller 212 toward the transfer section 240, a pair of timing rollers 222 that hold the leading end of the paper P conveyed by the roller 221 and wait, sending the paper to the transfer section 240 at a predetermined timing, and a paper discharge roller 223 that discharges the paper P with the fixed color toner image onto a paper discharge tray 224.

[0073] The image forming unit 230 includes, spaced apart from each other from left to right in the drawing, an image forming unit 180Y that forms an image using a developer containing yellow toner, an image forming unit 180C that uses a developer containing cyan toner, an image forming unit 180M that uses a developer containing magenta toner, an image forming unit 180K that uses a developer containing black toner, chargers 232Y, 232C, 232M, and 232K, and an exposure unit 233. The exposure unit 233 includes a light source 233a and polygon mirrors 233bY, 233bC, 233bM, and 233bK. The exposure unit 233 also includes toner bottles 234Y, 234M, 234C, and 234K, sub-hoppers 160Y, 160M, 160C, and 160K, and cleaners 236Y, 236M, 236C, and 236K. In addition, when referring to any image forming unit among the image forming units (Y, C, M, K), In this case, it is called an image forming unit.

[0074] The developer contains toner and carrier. The four image forming units (Y, C, M, K) have substantially the same mechanical configuration, except for the developer used in each.

[0075] The transfer unit 240 includes a drive roller 241 and a driven roller 242, an intermediate transfer belt 243 that can rotate counterclockwise in the figure as the drive roller 241 is driven, primary transfer rollers (244Y, 244C, 244M, 244K) that are arranged opposite photosensitive drums 231Y, 231C, 231M, and 231K, respectively, across the intermediate transfer belt 243, and secondary opposing rollers 245 and 246 that are arranged opposite each other across the intermediate transfer belt 243 at the position where the toner image is transferred to paper.

[0076] The fixing unit 250 has a heater installed inside and is equipped with a fixing belt 251 that heats the paper P, and a pressure roller 252 that forms a nip by rotatably applying pressure to the fixing belt 251. This applies heat and pressure to the color toner image on the paper P, fixing the color toner image. The paper P with the fixed color toner image is discharged to a paper discharge tray 224 by a paper discharge roller 223, completing the series of image formation processes.

[0077] (Process cartridge) The process cartridge according to the present invention is molded to be detachably mountable to various image forming apparatuses, and includes at least an electrostatic latent image carrier that carries an electrostatic latent image, and developing means that develops the electrostatic latent image carried on the electrostatic latent image carrier with the developer of the present invention to form a toner image. The process cartridge may further include other means, if necessary.

[0078] The developing means includes at least a developer container that contains the developer of the present invention and a developer carrier that carries and transports the developer contained in the developer container. The developing means may further include a regulating member or the like for regulating the thickness of the developer carried.

[0079] Figure 2 shows an example of a process cartridge according to the present invention. The process cartridge 110 includes a photoreceptor drum 10, a corona charger 58, a developing device 40, a transfer roller 80, and a cleaning device 90. L is a laser beam, and 95 is a sheet P.

Example

[0080] Hereinafter, the present invention will be further described with reference to examples, but the present invention is not limited to the following examples. In the following description, "parts" and "%" represent "parts by mass" and "mass%", respectively.

[0081] <Production of Resin Particles 1-7> (Synthesis of Amorphous Polyester Resin) Into a four-necked flask equipped with a nitrogen inlet tube, a dehydrating tube, a stirrer, and a thermocouple, bisphenol A ethylene oxide 2 mol adduct, bisphenol A propylene oxide 2 mol adduct, terephthalic acid, and adipic acid were charged such that the molar ratio of bisphenol A propylene oxide 2 mol adduct to bisphenol A ethylene oxide 2 mol adduct (bisphenol A propylene oxide 2 mol adduct / bisphenol A ethylene oxide 2 mol adduct) was 60 / 40, the molar ratio of terephthalic acid to adipic acid (terephthalic acid / adipic acid) was 97 / 3, and the molar ratio of hydroxyl group to carboxyl group OH / COOH was 1.3. The reaction was carried out at normal pressure and 230 °C for 8 hours with titanium tetraisopropoxide (500 ppm with respect to the resin component). After further reacting for 4 hours under a reduced pressure of 10 mmHg to 15 mmHg, trimellitic anhydride was added to the reaction vessel to a proportion of 1 mol% with respect to the total resin component, and the reaction was carried out at 180 °C, normal pressure, for 3 hours to obtain [amorphous polyester resin-1].

[0082] <Introduction of PET> Flaky recycled PET was mixed such that the solid content of recycled PET in 100 parts of [amorphous polyester resin-1] was the number of parts shown in Table 2 when mixing the materials for [synthesis of amorphous polyester resin] above. The numerical values of PET in Table 2 are the number of parts in 100 parts of amorphous polyester resin.

[0083] <Preparation of wax dispersion> To 720 parts of ion-exchanged water, 180 parts of ester wax (WE-11, manufactured by NOF Corporation, synthetic wax made from plant-derived monomers, melting point 67°C) and 17 parts of an anionic surfactant (Neogen SC, sodium dodecylbenzenesulfonate, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) were added. The mixture was dispersed in a homogenizer while heated to 90°C, to obtain [Wax Dispersion-1].

[0084] <Preparation of pigment masterbatch> 1,200 parts of water, 500 parts of carbon black (Printex 35, manufactured by Dexa) [DBP oil absorption = 42 mL / 100 mg, pH = 9.5], and 500 parts of [amorphous polyester resin-1] were added and mixed in a Henschel mixer (manufactured by Nippon Coke and Engineering Co., Ltd.). The mixture was kneaded using two rolls at 150°C for 30 minutes, then rolled and cooled, and pulverized in a pulverizer to obtain [pigment masterbatch-1].

[0085] <Preparation of oil phase> 200 parts of [Wax Dispersion-1], 750 parts of [Amorphous Polyester Resin-1], and 100 parts of [Pigment Masterbatch-1] were placed in a container and mixed at 5,000 rpm for 60 minutes using a TK Homomixer (manufactured by Primix Corporation) to obtain [Oil Phase 1]. [Oil phase 2] was prepared in the same manner as [Oil phase 1], except that the amount of [Wax dispersion liquid-1] was changed to 190 parts and the amount of [Amorphous polyester resin-1] was changed to 760 parts. [Oil phase 3] was prepared in the same manner as [Oil phase 1], except that the amount of [Wax dispersion liquid-1] was changed to 210 parts and the amount of [Amorphous polyester resin-1] was changed to 740 parts. The blending ratio of each component in [Oil Phase 1] to [Oil Phase 3] is shown in Table 1. The numerical values ​​of the blending ratios are in parts.

[0086] [Table 1]

[0087] <Preparation of aqueous phase> 990 parts of water, 20 parts of sodium dodecyl sulfate, and 90 parts of ethyl acetate were mixed and stirred to obtain [aqueous phase 1].

[0088] <Emulsification> 700 parts of [Oil Phase 1] were stirred at 8,000 rpm using a TK Homomixer, and 20 parts of 28% aqueous ammonia were added. After mixing for 10 minutes, 1,200 parts of [Aqueous Phase 1] were gradually added dropwise to obtain [Emulsified Slurry 1]. [Emulsified slurry 2] was prepared in the same manner as [Oil phase 1], except that [Oil phase 1] was changed to [Oil phase 2]. [Emulsified slurry 3] was prepared in the same manner as [Oil phase 1], except that [Oil phase 1] was changed to [Oil phase 3].

[0089] <Solvent removal> [Emulsified slurry 1] was placed in a container equipped with a stirrer and a thermometer, and the solvent was removed at 30°C for 180 minutes, yielding [solvent-removed slurry 1]. [Desolvated slurry 2] was prepared in the same manner as [Desolvated slurry 1], except that [Emulsified slurry 1] was changed to [Emulsified slurry 2]. [Desolvated Slurry 3] was prepared in the same manner as [Desolvated Slurry 1], except that [Emulsified Slurry 1] was changed to [Emulsified Slurry 3].

[0090] <Preparation of shell emulsion> (Production of Shell Resin 1) A 5L four-neck flask equipped with a nitrogen inlet tube, dehydration tube, stirrer, and thermocouple was charged with 22 parts ethylene glycol, 18 parts glycerol, 80 parts terephthalic acid, 99 parts trimellitic anhydride, and 12.3 parts sodium 5-sulfoisophthalate. Tetrabutyl orthotitanate (1000 ppm relative to the total monomer amount) was added as a condensation catalyst. The mixture was heated to 230°C over 2 hours under a nitrogen stream and reacted for 5 hours while distilling off the resulting water. The mixture was then reacted for 4 hours under a reduced pressure of 5 to 15 mmHg. After cooling to 180°C, [Shell Resin 1] was obtained. The SP value was 10.8 (cal / cm). 3 )1 / 2 It was.

[0091] (Production of Shell Resin 2) A 5L four-neck flask equipped with a nitrogen inlet tube, dehydration tube, stirrer, and thermocouple was charged with 22 parts ethylene glycol, 18 parts glycerol, 80 parts terephthalic acid, 99 parts trimellitic anhydride, and 9.8 parts sodium 5-sulfoisophthalate. Tetrabutyl orthotitanate (1000 ppm relative to the total monomer amount) was added as a condensation catalyst. The mixture was heated to 230°C over 2 hours under a nitrogen stream and reacted for 5 hours while distilling off the resulting water. The mixture was then reacted for 4 hours under a reduced pressure of 5 to 15 mmHg and cooled to 180°C, yielding [Shell Resin 2]. The SP value was 10.5 (cal / cm). 3 ) 1 / 2 It was.

[0092] Here, the SP value means the solubility parameter according to the Fedors method, which is a value δ calculated based on the following formula described in [Robert F. Fedors, Polymer Engineering and Science, 14, 147-154]. Fedors' formula: δ = (ΣΔei / ΣΔvi) 1 / 2 where Δei is the evaporation energy of atoms and atomic groups (cal / mol), Δvi is the molar volume (cm 3 / mol).

[0093] (Preparation of Shell Emulsion) While stirring 400 parts of the [shell resin 1] solution in a TK homomixer at 8,000 rpm, 5.9 parts of 28% aqueous ammonia were added to achieve a neutralization rate of 100%, and after mixing for 10 minutes, 600 parts of an aqueous phase was gradually added dropwise to emulsify the [shell resin 1] in a phase-inversion manner. Furthermore, the phase inversion emulsified shell resin 1 was subjected to solvent removal using an evaporator to obtain [shell emulsion 1]. [Shell Emulsion 2] was prepared in the same manner as [Shell Emulsion 1], except that [Shell Resin 2] was subjected to phase inversion emulsification instead of [Shell Resin 1].

[0094] <Aggregation and shell formation process> 100 parts of [solvent-removed slurry 1] and 300 parts of ion-exchanged water were placed in a container and stirred for 1 minute. Next, 100 parts of a 3% magnesium chloride solution was added dropwise, and the mixture was stirred for an additional 5 minutes, and then the temperature was raised to 55° C. When the particle size reached 5.0 μm, 18 parts of [Shell Emulsion 1] was added, and 15 parts of a 3% aqueous magnesium chloride solution was added dropwise.The mixture was stirred for an additional 10 minutes, and then the temperature was raised to 65° C. and the mixture was stirred for 30 minutes. The flocculation step was completed by adding 50 parts of sodium chloride, and [flocculated slurry 1] was obtained.

[0095] <Fusion> [Agglomerated Slurry 1] was heated to 70° C. while stirring, and cooled when the desired average circularity of 0.957 was reached, to obtain [Dispersed Slurry 1].

[0096] <Washing and drying> 100 parts of [Dispersion Slurry 1] was filtered under reduced pressure, and then the following operations (1) to (4) were carried out twice to obtain [Filter Cake 1]. (1) 100 parts of ion-exchanged water was added to the filter cake, and the mixture was mixed with a TK homomixer (at 12,000 rpm for 10 minutes), followed by filtration. (2): 100 parts of a 10% aqueous sodium hydroxide solution is added to the filter cake of (1), After mixing with a TK homomixer (at 12,000 rpm for 30 minutes), the mixture was filtered under reduced pressure. (3): Add 100 parts of 10% hydrochloric acid to the filter cake of (2), The mixture was mixed in a TK homomixer (at 12,000 rpm for 10 minutes) and then filtered. (4): 300 parts of ion-exchanged water is added to the filter cake of (3), Mix using a TK homomixer (at 12,000 rpm for 10 minutes) and then filter. [Filter cake 1] was dried in a circulating air dryer at 45°C for 48 hours and sieved through a mesh with 75 µm openings to obtain [resin particles 1].

[0097] <External additive processing process> 100 parts of [Resin particles 1] and 2.0 parts of hydrophobic silica (HDK-2000, manufactured by Clariant) as an external additive were mixed in a Henschel mixer, and passed through a 500 mesh sieve to obtain [Toner 1]. The physical properties of the resin particles are shown in Table 3.

[0098] [Resin Particles 1] to [Resin Particles 7] were prepared in the same manner as [Resin Particles 1], except that the types and amounts of solvent-removed slurry and shell emulsion added, and the heating temperatures in the aggregation, shell formation, and fusion processes were changed as shown in Table 2. Next, [Resin Particles 1] to [Resin Particles 7] were treated with external additives in the same manner as [Resin Particles 1] to obtain [Toner 1] to [Toner 7].

[0099] <Production of Resin Particles 8> <Emulsification / solvent removal> 1,200 parts of [Water Phase 1] was added to a container containing [Oil Phase 1] and mixed for 20 minutes at 13,000 rpm using a TK Homomixer to obtain [Emulsified Slurry 4]. [Emulsified Slurry 4] was then placed in a container equipped with a stirrer and a thermometer, and the solvent was removed at 30°C for 8 hours to obtain [Desolvated Slurry 4].

[0100] <Washing and drying> 100 parts of [solvent-removed slurry 4] was filtered under reduced pressure, and then the following operations (1) to (4) were carried out twice to obtain [filter cake 8]. (1) 100 parts of ion-exchanged water was added to the filter cake, and the mixture was mixed with a TK homomixer (at 12,000 rpm for 10 minutes), followed by filtration. (2): 100 parts of a 10% aqueous sodium hydroxide solution is added to the filter cake of (1), After mixing with a TK homomixer (at 12,000 rpm for 30 minutes), the mixture was filtered under reduced pressure. (3): Add 100 parts of 10% hydrochloric acid to the filter cake of (2), The mixture was mixed in a TK homomixer (at 12,000 rpm for 10 minutes) and then filtered. (4): 300 parts of ion-exchanged water is added to the filter cake of (3), Mix using a TK homomixer (at 12,000 rpm for 10 minutes) and then filter. The [filter cake 8] was dried in a circulating air dryer at 45° C. for 48 hours and sieved through a mesh with 75 μm openings to obtain [resin particles 8].

[0101] <External additive processing process> 100 parts of [Resin particles 8] and 2.0 parts of hydrophobic silica (HDK-2000, manufactured by Clariant) as an external additive were mixed in a Henschel mixer, and the mixture was passed through a 500 mesh sieve to obtain [Toner 8].

[0102] <Production of Resin Particles 9> <Emulsification / solvent removal> 1,200 parts of [Water Phase 1] was added to the vessel containing [Oil Phase 3], and mixed with a TK Homomixer at a rotation speed of 13,000 rpm for 20 minutes to obtain [Emulsified Slurry 5]. [Emulsified Slurry 5] was placed in a container equipped with a stirrer and a thermometer, and the solvent was removed at 30° C. for 8 hours, yielding [Desolvated Slurry 5].

[0103] <Washing and drying> 100 parts of [solvent-removed slurry 5] was filtered under reduced pressure, and then the following operations (1) to (4) were carried out twice to obtain [filter cake 9]. (1) 100 parts of ion-exchanged water was added to the filter cake, and the mixture was mixed with a TK homomixer (at 12,000 rpm for 10 minutes), followed by filtration. (2): 100 parts of a 10% aqueous sodium hydroxide solution is added to the filter cake of (1), After mixing with a TK homomixer (at 12,000 rpm for 30 minutes), the mixture was filtered under reduced pressure. (3): Add 100 parts of 10% hydrochloric acid to the filter cake of (2), The mixture was mixed in a TK homomixer (at 12,000 rpm for 10 minutes) and then filtered. (4): 300 parts of ion-exchanged water is added to the filter cake of (3), Mix using a TK homomixer (at 12,000 rpm for 10 minutes) and then filter. [Filter cake 9] was dried in a circulating air dryer at 45° C. for 48 hours and sieved through a mesh with 75 μm openings to obtain [resin particles 9].

[0104] <External additive processing process> 100 parts of [Resin particles 9] and 2.0 parts of hydrophobic silica (HDK-2000, manufactured by Clariant) as an external additive were mixed in a Henschel mixer, and the mixture was passed through a 500 mesh sieve to obtain [Toner 9].

[0105] Using these toners, the low temperature fixability and charging stability were evaluated. The results are shown in Table 3.

[0106] [Evaluation method] <Low temperature fixability> Composite resin particles are applied to the paper surface at a density of 0.8 mg / cm 2 Place evenly so that it looks like this. In this case, the powder is placed on the paper surface using a printer without a thermal fixing device. Other methods may be used as long as they can uniformly apply the powder at the above weight density. The paper was fixed to the pressure roller at a fixing speed (heating roller peripheral speed) of 213 mm / sec and a fixing pressure (pressure roller pressure) of 10 kg / cm. 2 The temperature at which cold offset occurs (MFT) was measured when the paper was passed through the above conditions. The lower the temperature at which cold offset occurs, the better the low-temperature fixability. A and B were considered acceptable, and C and D were considered unacceptable. [Cold offset evaluation criteria] Rank Minimum fixing temperature A: Below 130℃ B: Over 130℃ and below 135℃ C: Over 135℃ but below 140℃ D: Over 140℃

[0107] <Charging stability> The developer was set in a modified commercially available digital full-color printer (imagioNeo C455), and a running evaluation was performed on 300,000 sheets of an image chart with a 50% image area in monochrome mode.The charge stability was then evaluated based on the change in the charge amount of the carrier after this running, in accordance with the evaluation criteria. The amount of change in charge amount was as follows: That is, the container was conditioned in an open system for at least 30 minutes in an environment with a temperature of 23°C and a relative humidity of 50% (M / M environment), and then 6,000 g of the initial carrier and 0.452 g of resin particles were added to a stainless steel container, which was then sealed and operated for 5 minutes at 150 using a shaker (YS-LD, manufactured by Yayoi Co., Ltd.), shaking approximately 1,100 times to prepare a frictionally charged sample. The charge amount of the sample measured using the blow-off method (TB-200 manufactured by Toshiba Chemical Co., Ltd.) was defined as Q1, and the charge amount of the carrier obtained by removing the resin particles in the developer after running using a blow-off device was measured using the same method and defined as Q2. The amount of change in charge amount was determined as the absolute value (|Q1-Q2|) of the difference between charge amount Q1 and charge amount Q2. (Evaluation criteria) A: The amount of change in charge is less than 10 μc / g. B: The amount of change in charge amount is 10 μc / g or more and less than 15 μc / g. C: The amount of change in charge amount is 15 μc / g or more and less than 20 μc / g. D: The amount of change in charge is 20 μc / g or more.

[0108] [Table 2]

[0109] [Table 3]

[0110] The present invention includes, for example, the following aspects. (1) Resin particles having a core-shell structure containing a binder resin and an organic compound having a sulfo group, In the measurement of the depth profile of the resin particle surface by time-of-flight secondary ion mass spectrometry, when the secondary ion intensity derived from a sulfo group at t (nm) from the outermost surface of the resin particle surface is I (t), In the range of 0 < t < 100, it is characterized by satisfying the following formulas (1) and (2) Resin particles. I(100) < I(t) < I(0) Formula (1) 0.005 < I(100) Formula (2) (2) In the measurement of the depth profile of the secondary ions on the surface of the resin particles, When the secondary ion intensity derived from the sulfo group contained in the resin particles at t = 100 is I(100), When the secondary ion intensity derived from the sulfo group contained in the resin particles at t = 20 is I(20), The resin particles according to (1) above, which satisfy the following formula (3). I(100) < I(20) Formula (3) (3) The resin particles according to (1) or (2) above, wherein the binder resin contains recycled resin or biomass-derived resin. (4) The resin particles according to (3) above, wherein the recycled resin is polyethylene terephthalate (PET) and / or polybutylene terephthalate (PBT). (5) The resin particles according to any one of (1) to (4) above, which are produced by an emulsion polymerization aggregation method. (6) The resin particles according to any one of (1) to (5) above, further containing a colorant and a release agent. (7) A toner characterized in that an external additive is added to the resin particles according to any one of (1) to (6) above. (8) A toner container unit characterized by containing the toner according to (7) above. (9) A developer characterized by containing the toner according to (7) above and a carrier. (10) An electrostatic latent image carrier, Electrostatic latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier, a developing means having a toner for developing the electrostatic latent image formed on the electrostatic latent image carrier to form a visible image, An image forming apparatus, wherein the toner is the toner described in (7) above. [Explanation of symbols]

[0111] 10 Photosensitive drum 40 Developer 58 Corona charger 80 Transfer roller 90 Cleaning Device 110 Process cartridge 160Y Sub Hopper (Yellow) 160C Sub Hopper (Cyan) 160M Sub Hopper (Magenta) 160K Sub Hopper (Black) 180Y Image Forming Unit (Yellow) 180C Image Forming Unit (Cyan) 180M Image Forming Unit (Magenta) 180K Image Forming Unit (Black) 210 Paper feed section 211 Paper cassette 212 Paper feed roller 220 Conveyor 221 Laura 222 Timing roller 223 Paper ejection roller 224 Paper output tray 230 Image creation section 231Y Photoconductor drum (yellow) 231C Photoconductor drum (cyan) 231M Photoconductor Drum (Magenta) 231K Photoconductor Drum (Black) 232Y Charger (Yellow) 232C Charger (cyan) 232M Charger (Magenta) 232K Charger (Black) 233 Exposure device 233a light source 233bY Polygon Mirror (Yellow) 233bC Polygon Mirror (Cyan) 233bM Polygon Mirror (Magenta) 233bK Polygon Mirror (Black) 234Y Toner Bottle (Yellow) 234C Toner Bottle (Cyan) 234M Toner Bottle (Magenta) 234K Toner Bottle (Black) 236Y Cleaning Device (Yellow) 236C Cleaner (cyan) 236M Cleaner (Magenta) 236K Cleaner (Black) 240 Transcription Unit 241 Drive roller 242 driven roller 243 Intermediate transfer belt 244 Primary transfer roller 244Y Primary Transfer Roller (Yellow) 244C Primary transfer roller (cyan) 244M Primary Transfer Roller (Magenta) 244K Primary Transfer Roller (Black) 245 Secondary opposing roller 246 Secondary transfer roller 250 Fixing unit 251 Fixing belt 252 pressure roller L Laser P paper [Prior art documents] [Patent documents]

[0112] [Patent Document 1] JP 2019-090900 A [Patent Document 2] Japanese Patent Application Laid-Open No. 2008-233175 [Patent Document 3] Japanese Patent Application Laid-Open No. 2012-137730

Claims

1. Resin particles having a core-shell structure, containing a binder resin and an organic compound having a sulfo group, In a depth profile measurement of a resin particle surface by time-of-flight secondary ion mass spectrometry, when the intensity of secondary ions derived from sulfo groups at a distance t (nm) from the outermost surface of the resin particle surface is defined as I(t), The following formulas (1) and (2) are satisfied in the range of 0<t<100: Resin particles. I(100)<I(t)<I(0) Formula (1) 0.005<I(100) Equation (2)

2. In measuring the depth profile of secondary ions on the surface of the resin particles, The secondary ion intensity derived from the sulfo group contained in the resin particles at t=100 is defined as I(100), When the secondary ion intensity derived from the sulfo group contained in the resin particles at t=20 is I(20), The resin particles according to claim 1, which satisfy the following formula (3): I(100)<I(20) Equation (3)

3. The resin particles according to claim 1 or 2, wherein the binder resin contains a recycled resin or a biomass-derived resin.

4. The resin particles according to claim 3, wherein the recycled resin is polyethylene terephthalate (PET) and / or polybutylene terephthalate (PBT).

5. 3. The resin particles according to claim 1, wherein the resin particles are produced by an emulsion polymerization flocculation method.

6. The resin particles according to claim 1 or 2, further comprising a colorant and a release agent.

7. 7. A toner comprising the resin particles according to claim 6 and an external additive added thereto.

8. A toner storage unit containing the toner according to claim 7.

9. A developer comprising the toner according to claim 7 and a carrier.

10. an electrostatic latent image carrier; an electrostatic latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier; a developing means having a toner for developing the electrostatic latent image formed on the electrostatic latent image carrier to form a visible image, 8. An image forming apparatus, wherein the toner is the toner according to claim 7.

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