JP6825554B2 - toner - Google Patents

Description

The present invention relates to toner.

A toner containing a plurality of toner particles including a core and a shell layer covering the surface of the core is known (see, for example, Patent Document 1). By covering the core of the toner particles with a shell layer, the heat-resistant storage stability of the toner can be improved.

Japanese Unexamined Patent Publication No. 2004-294469

However, it is difficult to obtain a toner having excellent hot offset resistance while suppressing the aggregation of the toner during storage only by the technique disclosed in Patent Document 1.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a toner having excellent hot offset resistance while suppressing aggregation of the toner during storage.

The toner according to the present invention contains a plurality of toner particles including a core and a shell layer that partially covers the surface of the core. The core contains a binder resin and a plurality of release agent domains. The binding resin includes a polyester resin. The acid value of the release agent constituting the release agent domain is 4 mgKOH / g or less. The dispersion diameter of the release agent domain is 300 nm or more and 700 nm or less. The shell layer contains a monomer polymer containing at least a compound represented by the following formula (1).

In the formula (1), R ¹ represents a hydrogen atom or an alkyl group which may have a substituent.

According to the present invention, it is possible to provide a toner having excellent hot offset resistance while suppressing the aggregation of the toner during storage.

It is a figure which shows an example of the cross-sectional structure of the toner particle contained in the toner which concerns on this invention.

Hereinafter, preferred embodiments of the present invention will be described. If the evaluation results (values indicating the shape, physical properties, etc.) of the powder (more specifically, toner particles, etc.) are not specified, a considerable number of average particles are selected from the powder. It is the number average of the values measured for each of the average particles. Unless otherwise specified, the measured value of the medium volume diameter (D ₅₀ ) of the powder is based on the Coulter principle (pore electrical resistance method) using "Coulter Counter Multisizer 4" manufactured by Beckman Coulter Co., Ltd. It is the median diameter measured based on. The average number of powders, unless otherwise specified, is the average number of circles of primary particles (diameter of a circle having the same area as the projected area of the primary particles) measured using a scanning electron microscope. The value. The number average primary particle diameter of the powder is, for example, the average number of circle-equivalent diameters of 100 primary particles. Further, the chargeability means the chargeability in triboelectric charging unless otherwise specified. The strength of positive charging (or the strength of negative charging) in triboelectric charging can be confirmed by a well-known charging train or the like. For example, the toner is triboelectrically charged by mixing with a standard carrier (anionic: N-01, cationic: P-01) provided by the Imaging Society of Japan and stirring. The surface potential of the measurement target is measured with, for example, KFM (Kelvin probe force microscope) before and after triboelectric charging, and it is shown that the measurement target having a larger change in potential before and after triboelectric charging has stronger chargeability.

The softening point (Tm) is a value measured using a high-grade flow tester (“CFT-500D” manufactured by Shimadzu Corporation) unless otherwise specified. In the S-curve (horizontal axis: temperature, vertical axis: stroke) measured by the heightened flow tester, the temperature that becomes "(baseline stroke value + maximum stroke value) / 2" becomes Tm (softening point). Equivalent to. The endothermic curve (vertical axis: heat flow (DSC signal)) measured using a differential scanning calorimeter (“DSC-6220” manufactured by Seiko Instruments Inc.) unless otherwise specified, is the measured value of the melting point (Mp). , Horizontal axis: temperature) is the temperature of the maximum endothermic peak. This endothermic peak appears due to the melting of the crystallization site. Unless otherwise specified, the measured acid value is a value measured according to "JIS (Japanese Industrial Standards) K0070-1992".

Hereinafter, the compound and its derivative may be collectively referred to by adding "system" after the compound name. When the polymer name is represented by adding "system" after the compound name, it means that the repeating unit of the polymer is derived from the compound or its derivative. In addition, acrylic and methacrylic may be collectively referred to as "(meth) acrylic". In addition, acrylonitrile and methacrylonitrile may be collectively referred to as "(meth) acrylonitrile". The "main component" of a material, unless otherwise specified, means the component most abundant in the material on a mass basis.

<Toner>
The toner according to this embodiment can be suitably used for developing an electrostatic latent image, for example, as a positively charged toner. The toner of the present embodiment is a powder containing a plurality of toner particles (particles having a configuration described later). The toner may be used as a one-component developer. Further, the toner and the carrier may be mixed using a mixing device (for example, a ball mill) and used as a two-component developer.

The toner according to the present embodiment includes a plurality of toner particles including a core and a shell layer that partially covers the surface of the core. The core contains a binder resin and multiple release agent domains. The toner particles may further include an external additive. When the toner particles further include an external additive, the toner particles include a toner mother particle having a core and a shell layer, and an external additive. The external additive adheres to the surface of the toner matrix particles. If it is not necessary, the external additive may be omitted. When the external additive is omitted, the toner mother particles correspond to the toner particles.

If necessary, the core may contain an internal additive (more specifically, a colorant, a charge control agent, a magnetic powder, etc.) in addition to the binder resin and the release agent domain. Further, the binding resin in the core contains a polyester resin. The acid value of the release agent constituting the release agent domain is 4 mgKOH / g or less. The dispersion diameter of the release agent domain is 300 nm or more and 700 nm or less. The method for measuring the dispersion diameter of the release agent domain is the same method as in Examples described later or an alternative method thereof.

The shell layer contains a monomer polymer containing at least a compound represented by the following formula (1) (hereinafter, may be referred to as compound (1)).

In formula (1), R ¹ represents a hydrogen atom or an alkyl group which may have a substituent. The alkyl group includes a linear alkyl group, a branched chain alkyl group, and a cyclic alkyl group. Preferably, R ¹ represents a hydrogen atom, a methyl group, an ethyl group, or an isopropyl group.

By providing the toner according to the present embodiment with the above-mentioned configuration, it is possible to improve the hot offset resistance while suppressing the aggregation of the toner during storage. The reason is presumed as follows.

In the toner according to the present embodiment, since the binder resin in the core contains a polyester resin, a carboxyl group is relatively contained in the region where the binder resin is exposed in the surface region of the core before the shell layer is formed. There are many. On the other hand, since the acid value of the release agent constituting the release agent domain is 4 mgKOH / g or less, the carboxyl group of the region where the release agent domain is exposed in the surface region of the core before forming the shell layer The number is relatively small. Therefore, when the shell layer is composed of a polymer of a monomer containing at least the compound (1), the oxazoline group of the compound (1) is formed in the region where the binder resin is exposed rather than the region where the release agent domain is exposed. It becomes easier to react with the surface of the core. Therefore, the shell layer preferentially covers the region where the binder resin is exposed over the region where the release agent domain is exposed. In addition, since the dispersion diameter of the release agent domain is 300 nm or more, for example, at least a part of the surface region of the core where the release agent domain exists is not covered with the shell layer. As a result, when the toner is fixed, the mold release agent exudes from the region not covered by the shell layer, and it is considered that the mold release property of the toner is improved. Therefore, according to the toner according to the present embodiment, the hot offset resistance can be improved.

Further, in the toner according to the present embodiment, since the dispersion diameter of the release agent domain is 700 nm or less, the exudation of the release agent from the core during storage tends to be suppressed. Therefore, according to the toner according to the present embodiment, it is possible to suppress the aggregation of toner particles due to, for example, exudation of the release agent during storage.

The dispersion diameter of the release agent domain can be adjusted in the toner manufacturing method described later, for example, by changing the melt-kneading conditions in the melt-kneading step of the toner material. For example, when the toner material is melt-kneaded using a screw extruder, the dispersion diameter of the release agent domain can be adjusted by changing the screw rotation speed of the screw extruder.

[Structure of toner particles]
Hereinafter, the configuration of the toner particles contained in the toner according to the present embodiment will be described with reference to FIG. FIG. 1 is a diagram showing an example of a cross-sectional structure of toner particles contained in the toner according to the present embodiment. For ease of explanation, a case where the toner particles 1 shown in FIG. 1 are toner particles without an external additive will be described.

As shown in FIG. 1, the toner particles 1 include a core 2 and a shell layer 3 that partially covers the surface of the core 2. The core 2 contains a binder resin 21 and a plurality of release agent domains 22.

The binding resin 21 contains a polyester resin. The acid value of the release agent constituting the release agent domain 22 is 4 mgKOH / g or less. The dispersion diameter of the release agent domain 22 is 300 nm or more and 700 nm or less (hereinafter, may be referred to as a specific range). The shell layer 3 contains a monomeric polymer containing at least compound (1).

In the toner particles 1, at least a part of the surface region of the core 2 in which the mold release agent domain 22 is present is not covered with the shell layer 3. That is, at least a part of the region 2A is exposed without the release agent domain 22 being covered with the shell layer 3. As a result, when the toner is fixed, the release agent contained in the release agent domain 22 exudes from the exposed region 2A, so that the release property of the toner is enhanced, and as a result, the hot offset resistance can be improved. it can. Further, normally, when the shell layer is provided, the exudation of the release agent from the core is suppressed, but since the toner particles 1 exude from the exposed region 2A of the release agent, even if the shell layer 3 is provided. , Hot offset resistance can be improved.

Of the surface area of the core 2, the area ratio occupied by the exposed area 2A in which the release agent domain 22 is not covered by the shell layer 3 (hereinafter, may be referred to as the exposed area ratio of the release agent domain). In order to further improve the hot offset resistance, it is preferably 10% or more. Further, in order to further suppress the aggregation of the toner during storage, the exposed area ratio of the release agent domain is preferably 20% or less, and more preferably 18% or less. The method for measuring the exposed area ratio of the release agent domain is the same method as in the examples described later or an alternative method thereof. The exposed area ratio of the release agent domain can be adjusted by changing the dispersion diameter of the release agent domain 22.

In order to obtain a toner suitable for image formation, the thickness of the shell layer 3 is preferably 1 nm or more and 400 nm or less. The thickness of the shell layer 3 can be measured by analyzing a TEM (transmission electron microscope) image of a cross section of the toner particle 1 using commercially available image analysis software (for example, "WinROOF" manufactured by Mitani Shoji Co., Ltd.). .. If the thickness of the shell layer 3 is not uniform in one toner particle 1, two straight lines orthogonal to each other at substantially the center of the cross section of the toner particle 1 are drawn at four places evenly separated (specifically, they are drawn. The thickness of the shell layer 3 is measured at each of the four points where the two straight lines intersect the shell layer 3, and the arithmetic mean of the obtained four measured values is the evaluation value of the toner particle 1 (shell layer 3). Thickness). The boundary between the core 2 and the shell layer 3 can be confirmed, for example, by selectively dyeing only the shell layer 3 of the core 2 and the shell layer 3. When the boundary between the core 2 and the shell layer 3 is unclear in the TEM image, the feature included in the shell layer 3 in the TEM image is obtained by combining TEM and electron energy loss spectroscopy (EELS). The boundary between the core 2 and the shell layer 3 can be clarified by mapping the elements.

In order to obtain a toner suitable for image formation, the volume median diameter (D ₅₀ ) of the toner particles 1 is preferably 4 μm or more and 9 μm or less.

The toner according to this embodiment may contain toner particles other than the toner particles 1. In the toner according to the present embodiment, in order to further suppress the aggregation of the toner during storage and further enhance the hot offset resistance, the total content of the toner particles 1 in all the toner particles is 80% by mass or more. Is more preferable, 90% by mass or more is more preferable, and 100% by mass is particularly preferable.

Although an example of toner particles contained in the toner according to the present embodiment has been described above with reference to FIG. 1, the present invention is not limited thereto. For example, the toner particles contained in the toner according to the present invention may include an external additive (not shown). For example, the toner particles 1 shown in FIG. 1 are used as toner mother particles, and the toner particles having an external additive (a plurality of external agent particles) attached to the surface of the toner mother particles are the toner particles contained in the toner according to the present invention. May be.

[Elements of toner particles]
Next, the elements of the toner particles contained in the toner according to the present embodiment will be described.

(Bundling resin)
In the core, the binder resin occupies most of the components (for example, 80% by mass or more). Therefore, it is considered that the properties of the binder resin have a great influence on the properties of the entire core. By using a plurality of types of resins in combination as the binder resin, the properties of the binder resin (more specifically, acid value, Tm, etc.) can be adjusted.

In order to enhance the reactivity of compound (1) with the oxazoline group, the acid value of the binder resin contained in the core is preferably 10 mgKOH / g or more. Further, in order to easily adjust the dispersion diameter of the release agent domain within the above specific range, the acid value of the binder resin is preferably 40 mgKOH / g or less.

The binding resin contains a polyester resin. In order to enhance the dispersibility of the release agent domain and further improve the hot offset resistance of the toner, a non-crystalline polyester resin is preferable as the polyester resin.

Further, it is preferable that the core further contains a crystalline polyester resin in addition to the non-crystalline polyester resin as the polyester resin. When the core contains a non-crystalline polyester resin and a crystalline polyester resin as the binder resin, it is possible to improve the low temperature fixability of the toner while increasing the dispersibility of the release agent domain. This makes it possible to improve the low temperature fixability of the toner while further improving the hot offset resistance of the toner. In this case, the mixing ratio of the non-crystalline polyester resin and the crystalline polyester resin is not particularly limited, and is, for example, in the range of 1 part by mass or more and 30 parts by mass or less of the crystalline polyester resin with respect to 100 parts by mass of the non-crystalline polyester resin. It may be mixed with.

In order for the core to have an appropriate sharp melt property, it is preferable that the core contains a crystalline polyester resin having a crystallinity index of 0.90 or more and 1.20 or less as a binder resin. The crystallinity index of the polyester resin can be adjusted by changing the type or amount (blending ratio) of the material for synthesizing the polyester resin. The crystallinity index of the resin corresponds to the ratio (Tm / Mp) of the softening point (Tm: unit ° C.) of the resin to the melting point (Mp: unit ° C.) of the resin. For non-crystalline resins, it is often not possible to measure a definite Mp. Therefore, a resin whose endothermic peak cannot be clearly determined in the endothermic curve measured by using a differential scanning calorimeter may be determined to be a non-crystalline resin.

The polyester resin is obtained by polycondensing one or more polyhydric alcohols and one or more polyvalent carboxylic acids. Examples of the alcohol for synthesizing the polyester resin include divalent alcohols (more specifically, diols, bisphenols, etc.) as shown below, and trihydric or higher alcohols. Examples of the carboxylic acid for synthesizing the polyester resin include a divalent carboxylic acid and a trivalent or higher carboxylic acid as shown below. An anhydride of the polyvalent carboxylic acid may be used instead of the polyvalent carboxylic acid.

Preferable examples of diols are ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 2-butene-1,4. -Diol, 1,5-pentanediol, 2-penten-1,5-diol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, 1,4-benzenediol, polyethylene glycol, polypropylene Examples include glycol and polytetramethylene glycol.

Preferable examples of bisphenols include bisphenol A, hydrogenated bisphenol A, bisphenol A ethylene oxide adduct, and bisphenol A propylene oxide adduct.

Preferable examples of trihydric or higher alcohols are sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butane. Triol, 1,2,5-pentanetriol, glycerol, diglycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolethane, and 1,3,5- Examples include trihydroxymethylbenzene.

Preferable examples of divalent carboxylic acids include maleic acid, fumaric acid, succinic acid, succinic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, adipic acid, sebacic acid, succinic acid, malonic acid. , 1,10-decandicarboxylic acid, succinic acid, alkyl succinic acid (more specifically, n-butyl succinic acid, isobutyl succinic acid, n-octyl succinic acid, n-dodecyl succinic acid, isododecyl succinic acid, etc.), And alkenyl succinic acid (more specifically, n-butenyl succinic acid, isobutenyl succinic acid, n-octenyl succinic acid, n-dodecenyl succinic acid, isododecenyl succinic acid and the like).

Preferable examples of trivalent or higher valent carboxylic acids are 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1, 2,4-Butantricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxy-2-methyl-2-methylenecarboxypropane, 1,2,4-cyclohexanetricarboxylic acid, tetra (methylenecarboxyl) Examples include methane, 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid, and empole trimeric acid.

Suitable polyhydric alcohols for synthesizing non-crystalline polyester resins include plant-derived 1,2-propanediol and bisphenol (more specifically, bisphenol A ethylene adduct adduct, bisphenol A propylene oxide adduct). Etc.).

Plant-derived 1,2-propanediols can be produced, for example, by using chemical synthesis, fermentation methods, or a combination of these methods. In one example of a method for producing a plant-derived 1,2-propanediol, glycerin is obtained by hydrolyzing plant biomass containing saccharides such as glucose. Subsequently, a plant-derived 1,2-propanediol is obtained by reacting glycerin with hydrogen. As the vegetable biomass, for example, one or more vegetable fats and oils selected from the group consisting of soybean oil, coconut oil, palm oil, castor oil, and cacao oil can be used. As a method for hydrolyzing plant biomass, a chemical method using an acid or a base may be adopted, a biological method using an enzyme or a microorganism may be adopted, or another method may be adopted. May be good.

Suitable polyvalent carboxylic acids for synthesizing non-crystalline polyester resins include aromatic dicarboxylic acids (more specifically, terephthalic acid and the like) and unsaturated dicarboxylic acids (more specifically, fumaric acid and the like). ).

In order to easily adjust the dispersion diameter of the release agent domain to the above-mentioned specific range while increasing the reactivity of the compound (1) with the oxazoline group, the non-crystalline polyester resin is a plant-derived 1,2- A monomer polymer containing propanediol and terephthalic acid is preferred.

Suitable polyhydric alcohols for synthesizing crystalline polyester resins include α, ω-alkanediols (more specifically, 1,4-butanediol, 1,6-hexane) having 4 or more and 8 or less carbon atoms. Diol, etc.). Suitable polyvalent carboxylic acids for synthesizing crystalline polyester resins include α, ω-alkanedicarboxylic acids (more specifically) having 4 or more and 12 or less carbon atoms (including carbon atoms of two carboxyl groups). , Succinic acid, sebacic acid, 1,10-decandicarboxylic acid, etc.).

In order to easily adjust the dispersion diameter of the release agent domain to the above specific range while enhancing the reactivity of the compound (1) with the oxazoline group, 1,6-hexanediol and 1 are used as the crystalline polyester resin. , 10-Decandicarboxylic acid-containing monomeric polymers are preferred.

The core may contain a resin other than the polyester resin as the binding resin. As the resin other than the polyester resin, a thermoplastic resin other than the polyester resin is preferable. Examples of thermoplastic resins other than polyester resins include styrene resins, (meth) acrylic acid ester resins, olefin resins (more specifically, polyethylene resins, polypropylene resins, etc.), and vinyl resins (more specifically). , Vinyl chloride resin, polyvinyl alcohol, vinyl ether resin, N-vinyl resin, etc.), polyamide resin, and urethane resin. Further, a copolymer of each of these resins, that is, a copolymer in which an arbitrary repeating unit is introduced into the above resin (more specifically, a styrene- (meth) acrylic acid ester resin, a styrene-butadiene resin, etc.) ) Can also be used as a binding resin for the core. In order to enhance the reactivity between the oxazoline group of the compound (1) and the binder resin, the content of the polyester resin is preferably 80% by mass or more, preferably 90% by mass or more, based on the total amount of the binder resin. It is more preferable, and it is particularly preferable that it is 100% by mass.

(Colorant)
The core may contain a colorant. As the colorant, a pigment or dye known according to the color of the toner can be used. In order to form a high-quality image using the toner, the amount of the colorant is preferably 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the binder resin.

The core may contain a black colorant. An example of a black colorant is carbon black. Further, the black colorant may be a colorant that has been toned to black using a yellow colorant, a magenta colorant, and a cyan colorant.

The core may contain a color colorant. Examples of the color colorant include a yellow colorant, a magenta colorant, and a cyan colorant.

As the yellow colorant, for example, one or more compounds selected from the group consisting of condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and arylamide compounds can be used. Examples of the yellow colorant include C.I. I. Pigment Yellow (3,12,13,14,15,17,62,74,83,93,94,95,97,109,110,111,120,127,128,129,147,151,154,155 168, 174, 175, 176, 180, 181, 191 and 194), Naphthol Yellow S, Hansa Yellow G, and C.I. I. Bat yellow can be mentioned.

The magenta colorant is selected from the group consisting of, for example, condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. More than one compound can be used. Examples of the magenta colorant include C.I. I. Pigment Red (2, 3, 5, 6, 7, 19, 23, 48: 2, 48: 3, 48: 4, 57: 1, 81: 1, 122, 144, 146, 150, 166, 169, 177 , 184, 185, 202, 206, 220, 221 and 254).

As the cyan colorant, for example, one or more compounds selected from the group consisting of copper phthalocyanine compounds, anthraquinone compounds, and base dye lake compounds can be used. Examples of the cyan colorant include C.I. I. Pigment Blue (1, 7, 15, 15: 1, 15: 2, 15: 3, 15: 4, 60, 62, and 66), Phthalocyanine Blue, C.I. I. Bat Blue, as well as C.I. I. Acid blue can be mentioned.

(Release agent domain)
The core contains multiple release agent domains. The release agent constituting the release agent domain is not particularly limited as long as it is a release agent having an acid value of 4 mgKOH / g or less. In order to further suppress the aggregation of toner during storage and further enhance the hot offset resistance, the amount of the release agent domain should be 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the binder resin. It is preferable to have.

Examples of the release agent constituting the release agent domain include aliphatic hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, polyolefin copolymer, polyolefin wax, microcrystallin wax, paraffin wax, and Fishertropch wax; Oxide of aliphatic hydrocarbon wax such as polyethylene oxide wax, block copolymer of polyethylene oxide wax; plant wax such as candelilla wax, carnauba wax, wood wax, jojoba wax, rice wax; mitsuro, lanolin, whale Animal waxes such as wax; Mineral waxes such as ozokelite, selecin, petrolatum; Ester wax containing fatty acid esters such as montanic acid ester wax and Custer wax as main components; Wax in which part or all of fatty acid esters are deoxidized (wax For example, deoxidized carnauba wax) can be preferably used. In the present embodiment, one type of release agent may be used alone, or a plurality of types of release agents may be used in combination.

As the release agent constituting the release agent domain, paraffin wax is preferable in order to easily adjust the acid value to 4 mgKOH / g or less. In order to improve the compatibility between the binder resin and the release agent, a compatibilizer may be added to the core.

(Charge control agent)
The core may contain a charge control agent. The charge control agent is used, for example, for the purpose of improving the charge stability or charge rise characteristics of the toner. The charge rising characteristic of the toner is an index of whether or not the toner can be charged to a predetermined charge level in a short time.

By including a negatively charged charge control agent in the core, the anionic property of the core can be strengthened. Further, by incorporating a positively charged charge control agent into the core, the cationic property of the core can be strengthened.

Examples of positively charged charge control agents include pyridazine, pyrimidine, pyrazine, 1,2-oxazine, 1,3-oxazine, 1,4-oxazine, 1,2-thiazine, 1,3-thiazine, 1, 4-thiazine, 1,2,3-triazine, 1,2,4-triazine, 1,3,5-triazine, 1,2,4-oxadiazine, 1,3,4-oxadiazine, 1,2,6- Oxaziazine, 1,3,4-triazinezine, 1,3,5-triazineazine, 1,2,3,4-tetrazine, 1,2,4,5-tetrazine, 1,2,3,5-tetrazine, 1, Adin compounds such as 2,4,6-oxatriazine, 1,3,4,5-oxatriazine, phthalazine, quinazoline, quinoxalin; azinefast red FC, azinefast red 12BK, azine violet BO, azine brown 3G, azine light Direct dyes such as brown GR, azine dark green BH / C, azine deep black EW, azine deep black 3RL; acidic dyes such as niglosin BK, niglocin NB, niglocin Z; metal salts of naphthenic acid; higher organic carboxylic acids Metal salts; alkoxylated amines; alkylamides; benzyldecylhexylmethylammonium chloride, decyltrimethylammonium chloride, 2- (methacryloyloxy) ethyltrimethylammonium chloride, dimethylaminopropylacrylamide, quaternary ammonium chloride salts, etc. Be done. Only one of these charge control agents may be used, or two or more of these charge control agents may be used in combination. In order to provide a positively chargeable toner having excellent charge stability, it is preferable to use a quaternary ammonium salt as a charge control agent.

An example of a negatively charged charge control agent is an organometallic complex which is a chelate compound. As the organometallic complex, for example, an acetylacetone metal complex, a salicylic acid-based metal complex, and salts thereof are preferable.

The content of the charge control agent is preferably 0.1 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the binder resin in order to improve the charge stability.

(Magnetic powder)
The core may contain magnetic powder. Examples of the material of the magnetic powder include ferromagnetic metals (more specifically, iron, cobalt, nickel, etc.) and their alloys, ferromagnetic metal oxides (more specifically, ferrite, magnetite, chromium dioxide, etc.). , And a material that has been subjected to a ferromagnetization treatment (more specifically, heat treatment or the like). In the present embodiment, one kind of magnetic powder may be used alone, or a plurality of kinds of magnetic powder may be used in combination.

(Shell layer)
The shell layer contains a monomeric polymer containing at least compound (1). As the polymer constituting the shell layer, a polymer obtained by copolymerizing the compound (1) with another vinyl compound may be used. The vinyl compound is a compound having a vinyl group (CH ₂ = CH-) or a group in which hydrogen in the vinyl group is substituted (more specifically, ethylene, propylene, butadiene, vinyl chloride, (meth) acrylic). Acid, methyl (meth) acrylate, (meth) acrylonitrile, styrene, etc.). The vinyl compound can be additive-polymerized by the carbon-carbon double bond (C = C) contained in the vinyl group or the like to become a polymer (resin).

As the other vinyl compound, one or more vinyl compounds selected from the group consisting of (meth) acrylic acid alkyl esters which may have a substituent on the alkyl group and styrene-based monomers are preferable.

Examples of the acrylic acid alkyl ester that may have a substituent on the alkyl group include a compound represented by the following formula (2) (hereinafter, may be referred to as compound (2)).

In formula (2), R ² represents an alkyl group which may have a substituent. The alkyl group includes a linear alkyl group, a branched chain alkyl group, and a cyclic alkyl group. As the alkyl group, an alkyl group having 1 to 8 carbon atoms is preferable. When R ² represents an alkyl group having a substituent, a hydroxyl group is preferable as the substituent of the alkyl group. As R ² , methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, 2-ethylhexyl group, hydroxyethyl group, hydroxypropyl group, and hydroxybutyl group are preferable.

Examples of the methacrylic acid alkyl ester that may have a substituent on the alkyl group include a compound represented by the following formula (3) (hereinafter, may be referred to as compound (3)).

In formula (3), R ³ represents an alkyl group which may have a substituent. The alkyl group includes a linear alkyl group, a branched chain alkyl group, and a cyclic alkyl group. As the alkyl group, an alkyl group having 1 to 8 carbon atoms is preferable. When R ³ represents an alkyl group having a substituent, a hydroxyl group is preferable as the substituent of the alkyl group. As R ³ , methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, 2-ethylhexyl group, hydroxyethyl group, hydroxypropyl group, and hydroxybutyl group are preferable.

In order to further suppress the aggregation of toner during storage, the shell layer preferably contains a polymer obtained by copolymerizing compound (1) with at least one of compound (2) and compound (3).

The compound (1) forms a repeating unit represented by the following formula (1-1) (hereinafter, referred to as a repeating unit (1-1)) by addition polymerization. R ¹ in formula (1-1) has the same meaning as R ¹ in the formula (1).

The repeating unit (1-1) has an unopened ring oxazoline group. The unopened oxazoline group has a cyclic structure and exhibits strong positive chargeability. The unopened oxazoline group easily reacts with the carboxyl group, the aromatic sulfanyl group, and the aromatic hydroxyl group. For example, when the repeating unit (1-1) in the shell layer reacts with the carboxyl group of the polyester resin in the core, the oxazoline group is ring-opened as shown in the following formula (1-2), and the core and the shell layer are separated from each other. An amide ester bond is formed between them. By forming such a bond, the bond between the core and the shell layer is strengthened, and the detachment of the shell layer from the core is suppressed. Incidentally, R ¹ in formula (1-2) has the same meaning as R ¹ in the formula (1). * In the following formula (1-2) represents a portion connected to an atom in the polyester resin contained in the core.

The shell layer preferably contains a vinyl resin having a repeating unit (1-1) and a repeating unit represented by the formula (1-2) (hereinafter, referred to as a repeating unit (1-2)). .. Hereinafter, the vinyl resin having the repeating unit (1-1) and the repeating unit (1-2) may be referred to as vinyl resin A. The molar ratio of the repeating unit (1-1) and the repeating unit (1-2) in the vinyl resin A can be adjusted, for example, by changing the amount of the ring-opening agent used, which will be described later, in the shell layer forming step.

Since the oxazoline group (unopened ring) has strong positive chargeability, when the shell layer contains vinyl resin A, it is possible to provide a positively chargeable toner having excellent charging characteristics. As a material for forming the shell layer containing the vinyl resin A, for example, an oxazoline group-containing polymer aqueous solution (“Epocross (registered trademark) WS series” manufactured by Nippon Shokubai Co., Ltd.) can be used. Of these, "Epocross WS-300" contains a copolymer of 2-vinyl-2-oxazoline (a type of compound (1)) and methyl methacrylate. In addition, "Epocross WS-700" contains a copolymer of 2-vinyl-2-oxazoline, methyl methacrylate and butyl acrylate.

(External agent)
The toner particles may further include an external additive (a plurality of external agent particles). As a method of externalizing the external additive, for example, the toner particles 1 shown in FIG. 1 are used as the toner matrix particles, and the toner matrix particles (powder) and the external additive particles (powder) are stirred together. Then, a method of adhering the external additive particles to the surface of the toner mother particles can be mentioned.

In order to fully exert the function of the external additive while suppressing the detachment of the external agent particles from the shell layer, the amount of the external additive (when using multiple types of external agent particles, they are used. The total amount of the external additive particles) is preferably 0.5 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the toner mother particles.

Inorganic particles are preferable as the external additive particles, and silica particles and particles of metal oxides (more specifically, alumina, titanium oxide, magnesium oxide, zinc oxide, strontium titanate, barium titanate, etc.) are particularly preferable. preferable. In the present embodiment, one type of external additive particles may be used alone, or a plurality of types of external agent particles may be used in combination.

In order to improve the fluidity of the toner, it is preferable to use inorganic particles (powder) having an average number of primary particle diameters of 5 nm or more and 500 nm or less as the external additive particles.

The external additive particles may be surface-treated. For example, when silica particles are used as the external additive particles, the surface of the silica particles may be imparted with hydrophobicity and / or positive chargeability by a surface treatment agent. Examples of the surface treatment agent include a coupling agent (more specifically, a silane coupling agent, a titanate coupling agent, an aluminate coupling agent, etc.), a silazane compound (more specifically, a chain silazane compound, etc.). Cyclic silane compounds and the like) and silicone oils (more specifically, dimethyl silicone oils and the like) can be mentioned. As the surface treatment agent, a silane coupling agent and a silazane compound are particularly preferable. Preferable examples of the silane coupling agent include silane compounds (more specifically, methyltrimethoxysilane, aminosilane, etc.). Preferable examples of the silazane compound include HMDS (hexamethyldisilazane). When the surface of the silica substrate (untreated silica particles) is treated with a surface treatment agent, a large number of hydroxyl groups (-OH) present on the surface of the silica substrate are partially or wholly derived from the surface treatment agent. Substituted with a functional group. As a result, silica particles having a functional group derived from the surface treatment agent (specifically, a functional group having a stronger hydrophobicity and / or positive charge than the hydroxyl group) on the surface can be obtained.

[Toner manufacturing method]
Hereinafter, a suitable method for producing the toner according to the present embodiment will be described.

(Core manufacturing method)
Examples of the method for producing the core include an agglutination method and a pulverization method.

The agglutination method includes, for example, an agglutination step and a coalescence step. In the agglomeration step, fine particles containing the components constituting the core are agglomerated in an aqueous medium to form agglomerated particles. In the coalescence step, the components contained in the agglomerated particles are coalesced in an aqueous medium to form a core. In addition, the agglutination method tends to increase the environmental load because a large amount of chemical wastewater is generated.

Next, the pulverization method will be described. According to the pulverization method, the core can be produced relatively easily and the production cost can be reduced. In addition, the crushing method does not have a step of generating a large amount of chemical wastewater, so that the environmental load can be reduced. When the core is manufactured by the crushing method, the core manufacturing step includes, for example, a melt-kneading step and a crushing step. The core manufacturing step may further include a mixing step prior to the melt kneading step. Further, the core manufacturing step may further include at least one of a pulverization step and a classification step after the pulverization step.

In the mixing step, for example, a binder resin, a release agent having an acid value of 4 mgKOH / g or less, and an internal additive added as needed are mixed to obtain a mixture. In the melt-kneading step, the toner material is melted and kneaded to obtain a melt-kneaded product. As the toner material, for example, a mixture obtained in a mixing step is used. An example of a melt-kneading device that can be used in the melt-kneading step is a screw extruder (more specifically, a twin-screw extruder or the like). When a melt-kneaded product is obtained by a screw extruder, the dispersion diameter of the release agent domain contained in the obtained core can be adjusted to the above-mentioned specific range by changing the screw rotation speed of the screw extruder. In the pulverization step, the obtained melt-kneaded product is cooled to, for example, room temperature (25 ° C.) and then pulverized to obtain a pulverized product (core). When it is necessary to reduce the diameter of the pulverized product obtained in the pulverization step, a step of further pulverizing the pulverized product (fine pulverization step) may be carried out. Further, when the particle size of the pulverized product is made uniform, a step of classifying the obtained pulverized product (classification step) may be carried out. By the above steps, a core which is a pulverized product is obtained.

(Method of forming shell layer)
Subsequently, the core and the shell material (for example, an oxazoline group-containing polymer aqueous solution) are added to an aqueous medium (for example, ion-exchanged water).

The shell material (eg, an oxazoline group-containing polymer dissolved in an aqueous medium) adheres to the surface of the core in liquid. In order to uniformly adhere the shell material to the surface of the core, it is preferable to highly disperse the core in the liquid containing the shell material. In order to highly disperse the core in the liquid, the liquid may contain a surfactant, or the liquid may be agitated using a stirrer.

Subsequently, while stirring the liquid containing the shell material and the like, the temperature of the liquid is adjusted at a predetermined speed (for example, 0.1 ° C./min or more and 3 ° C./min or less) to a predetermined holding temperature (for example, 50 ° C. or more and 85 ° C. or less). Raise to below). During this temperature rise, a ring-opening agent (for example, an acetic acid aqueous solution) and / or a shell material (for example, an oxazoline group-containing polymer aqueous solution) for opening the oxazoline group of the shell material may be added. Further, after the temperature rise is completed (after reaching the holding temperature), a ring-opening agent (for example, an acetic acid aqueous solution) and / or a shell material (for example, an oxazoline group-containing polymer aqueous solution) may be added.

After the temperature rise is completed, the temperature of the liquid is kept at the above-mentioned holding temperature for a predetermined time (for example, 30 minutes or more and 4 hours or less) while stirring the liquid. It is considered that the reaction (immobilization of the shell layer) proceeds between the core and the shell material while the temperature of the liquid is kept high (or during the temperature rise). For example, the oxazoline group of the shell material reacts with the functional group existing on the surface of the binder resin constituting the core to open the ring, and an amide ester bond is formed between the core and the shell layer. As described above, in the present embodiment, the release agent having an acid value in a specific range is used, and the dispersion diameter of the release agent domain is adjusted to a specific range. Therefore, for example, in the surface region of the core, at least a part of the region where the release agent domain exists is exposed without being covered with the shell layer. The result is a dispersion of toner matrix particles comprising a core and a shell layer that partially covers the surface of the core.

After forming the shell layer, for example, aqueous ammonia is used to neutralize the dispersion of toner matrix particles. Subsequently, the dispersion of the toner matrix particles is cooled to, for example, room temperature (25 ° C.). Subsequently, for example, a Büchner funnel is used to filter the dispersion of toner matrix particles. As a result, the toner mother particles are separated from the liquid (solid-liquid separation), and a wet cake-like toner mother particles are obtained.

Subsequently, the toner mother particles are washed. Subsequently, the washed toner matrix particles are dried. After that, if necessary, the toner matrix particles and the external additive are mixed using a mixer (for example, an FM mixer manufactured by Nippon Coke Industries Co., Ltd.) to attach the external additive to the surface of the toner matrix particles. You may. The toner mother particles may be used as the toner particles without adhering the external additive to the toner mother particles. In this way, a toner containing a large number of toner particles is produced.

Hereinafter, examples of the present invention will be described. First, a method for measuring the acid value of the polyester resin and the release agent will be described.

<Measurement of acid value>
5 g of the sample was dissolved in 50 mL of tetrahydrofuran, several drops of an ethanol solution of phenolphthalein as an indicator were added, and then titration was performed with a 0.1 mol / L potassium hydroxide aqueous solution. As the sample, a binder resin, a release agent RA, a release agent RB, and a release agent RC, which will be described later, were used, respectively. Regarding the binder resin, 4.2 g of non-crystalline polyester resin PA (non-crystalline polyester resin synthesized by the method described later) and 0.8 g of crystalline polyester resin PB, depending on the mass ratio in the core described later. A sample mixed with (a crystalline polyester resin synthesized by a method described later) was used. The acid value (unit: mgKOH / g) is calculated from the amount of potassium hydroxide aqueous solution required to reach the end point and the mass of the sample subjected to titration, starting from the point where the color of the sample solution changes from colorless to purple. Calculated.

<Synthesis of binding resin>
[Preparation of plant-derived 1,2-propanediol]
First, palm oil, which is a vegetable oil, was hydrolyzed to obtain glycerin. Specifically, palm oil and an aqueous sodium hydroxide solution (concentration: 10% by mass) in an amount twice the amount required for completely saponifying the palm oil were added to the reaction vessel. Subsequently, the contents of the container were heated at a temperature of 150 ° C. to completely saponify palm oil (vegetable oil and fat). The glycerin aqueous solution was separated from the contents of the container after saponification, and the obtained glycerin aqueous solution was distilled. The distilled glycerin was treated with activated carbon to purify the glycerin.

Next, 200 g of ethylene glycol and 76 g of cupric nitrate trihydrate were added into a reaction vessel equipped with a reflux condenser. Subsequently, the contents of the container were stirred while heating at a temperature of 80 ° C. for 2 hours, 52 g of tetraethoxysilane was added dropwise, and the mixture was stirred while heating at a temperature of 80 ° C. for 2 hours. Then, after dropping 18 g of water into the container, the contents of the container were stirred at a temperature of 80 ° C. for 3 hours to obtain a precipitate in the container. The obtained precipitate was dried at a temperature of 120 ° C. and then fired in air at a temperature of 400 ° C. for 2 hours to obtain a copper / silica catalyst (copper content: 50% by mass). An aqueous solution containing 29.8 mg of tetraammine platinum (II) nitrate [Pt (NH ₃ ) ₄ (NO ₃ ) ₂ ] 29.8 mg was added to 3 g of the obtained copper / silica catalyst, and the mixture was dried by a rotary evaporator. The obtained solid is dried at a temperature of 120 ° C. and then fired in air at a temperature of 400 ° C. for 2 hours to obtain a copper-platinum / silica catalyst having a copper content of 50% by mass (mass ratio: Cu / Pt / Si = 50). /0.5/17) was obtained.

Subsequently, 2 g of the obtained copper-platinum / silica catalyst and 200 g of glycerin (purified glycerin) obtained in the above procedure were added to an iron autoclave having a capacity of 500 mL with a stirrer, and the air in the autoclave was replaced with hydrogen. did. Subsequently, the temperature inside the autoclave was raised to 230 ° C., and hydrogen gas (temperature 25 ° C.) was introduced into the autoclave at an introduction amount of 5 L / min, while the pressure was 2 MPa and the temperature was 230 ° C. The material of the above was reacted for 7 hours to obtain a reaction product (liquid). The obtained reaction product was purified by a conventional method to obtain a plant-derived 1,2-propanediol.

[Synthesis of non-crystalline polyester resin PA]
A 5-L volume flask equipped with a stirrer (“SM-104” sold by AS ONE Corporation), a nitrogen introduction tube, a thermocouple, a dehydration tube, and a rectification column was used as a reaction vessel. In this reaction vessel, 1142 g (alcohol component) of plant-derived 1,2-propanediol prepared as described above, 1743 g of terephthalic acid (carboxylic acid component), and 4 g of tin (II) dioctanoate (condensation catalyst). And added. While removing the water produced by the reaction, the contents of the container were reacted at a temperature of 230 ° C. for 15 hours under atmospheric pressure in a nitrogen atmosphere. Then, the pressure in the container was reduced to 8.3 kPa, and the contents of the container were reacted for another 1 hour under the conditions of a pressure of 8.3 kPa and a temperature of 230 ° C.

Subsequently, the pressure in the container was returned to atmospheric pressure, the temperature in the container was lowered to 180 ° C., and then 288 g of trimellitic anhydride was added into the container. Then, the temperature inside the container was raised to 210 ° C. at a rate of 10 ° C./hour. Subsequently, the contents of the container were reacted under atmospheric pressure at a temperature of 210 ° C. for another 10 hours. Subsequently, the pressure inside the container was reduced to 20 kPa, and the contents of the container were reacted for another 1 hour under the conditions of a pressure of 20 kPa and a temperature of 210 ° C. After completion of the reaction, the contents of the container were taken out and cooled to obtain a non-crystalline polyester resin PA.

[Synthesis of crystalline polyester resin PB]
1320 g of 1,6-hexanediol (alcohol component) and 1,10-decandicarboxylic acid in a 5 L 4-neck flask equipped with a thermometer (thermocouple), dehydration tube, nitrogen introduction tube, and stirrer. 2300 g (acid component), 4 g of dibutyltin oxide (condensation catalyst), and 3 g of hydroquinone (polymerization inhibitor) were added. Subsequently, the flask contents were reacted at a temperature of 200 ° C. and atmospheric pressure for 5 hours while removing the water produced by the reaction. Next, the contents of the flask were reacted for 1 hour under the conditions of a reduced pressure atmosphere (pressure 1.3 kPa) and a temperature of 200 ° C. After completion of the reaction, the contents of the flask were taken out and cooled. As a result, a crystalline polyester resin PB having a softening point (Tm) of 90 ° C., a melting point (Mp) of 75 ° C., and a crystallinity index (Tm / Mp) of 1.20 was obtained.

In the preparation of the core CA-1 described later, the acid value of the binder resin obtained by mixing 100 parts by mass of the non-crystalline polyester resin PA and 20 parts by mass of the crystalline polyester resin PB was 14 mgKOH / g. ..

<Making toner TA-1>
[Preparation of core CA-1]
Using an FM mixer (“FM-20B” manufactured by Nippon Coke Industries Co., Ltd.), 100 parts by mass of non-crystalline polyester resin PA, 20 parts by mass of crystalline polyester resin PB, and 10 parts by mass of mold release agent RA. (Nippon Seiwa Co., Ltd. paraffin wax "HNP-5"), 5 parts by mass of colorant (carbon black: Mitsubishi Chemical Industries, Ltd. "MA-100"), and 1 part by mass of charge control agent (4th grade) Ammonium salt: "BONTRON (registered trademark) P-51" manufactured by Orient Chemical Industries Co., Ltd.) was mixed. Subsequently, the obtained mixture was melt-kneaded using a twin-screw extruder (“PCM-30” manufactured by Ikegai Co., Ltd.) under the conditions of a material supply speed of 100 g / min, a screw rotation speed of 150 rpm, and a cylinder temperature of 140 ° C. .. Then, the obtained melt-kneaded product was cooled. Subsequently, the cooled melt-kneaded product was coarsely pulverized using a pulverizer (“Rotoplex®” manufactured by Hosokawa Micron Corporation). Subsequently, the obtained coarsely pulverized product was finely pulverized using a pulverizer (“Turbo Mill RS type” manufactured by Freund Turbo Co., Ltd.). Subsequently, the obtained finely pulverized product was classified using a classification machine (classification machine using the Coanda effect: "Elbow Jet EJ-LABO type" manufactured by Nittetsu Mining Co., Ltd.). As a result, a core CA-1 having a median volume diameter (D ₅₀ ) of 7.0 μm was obtained.

[Shell layer forming process]
Using a free mode mixer (“FM-10” manufactured by Nikko Co., Ltd.), 100 parts by mass of core CA-1 and 1 part by mass of oxazoline group-containing polymer aqueous solution in terms of solid content under the condition of a rotation speed of 120 rpm. ("Epocross WS-300" manufactured by Nikko Co., Ltd.) and 99 parts by mass of ion-exchanged water were mixed for 20 minutes. After putting the obtained mixture in a flask equipped with a thermometer and a stirring blade, ion-exchanged water was added to the flask so that the solid content concentration in the mixture was 20% by mass. Next, the temperature inside the flask was raised to 60 ° C. at a rate of 0.5 ° C./min while stirring the contents of the flask at a rotation speed of 120 rpm. After the temperature inside the flask reaches 60 ° C., 1 part by mass of an aqueous acetic acid solution (concentration: 1% by mass) is added, and the contents of the flask are stirred at a rotation speed of 120 rpm for 1 hour while keeping the temperature inside the flask at 60 ° C. Continued to stir.

Subsequently, an aqueous ammonia solution (concentration: 1% by mass) was added into the flask to adjust the pH of the contents of the flask to 7. Subsequently, the contents of the flask were cooled to a temperature of 25 ° C. to obtain a dispersion containing toner matrix particles.

[Washing process]
The dispersion liquid of the toner mother particles obtained as described above was filtered (solid-liquid separation) using a Büchner funnel to obtain a wet cake-shaped toner mother particles. Then, the obtained wet cake-like toner matrix particles were redispersed in ion-exchanged water and then filtered using a Büchner funnel. Further, redispersion and filtration were repeated 5 times to wash the toner matrix particles.

[Drying process]
Subsequently, the toner matrix particles were dried under the conditions of a hot air temperature of 45 ° C. and a blower air volume of 2 m ³ / min using a continuous surface modifier (“Coatmizer (registered trademark)” manufactured by Freund Sangyo Co., Ltd.). .. As a result, a powder of toner mother particles was obtained.

[External process]
Using an FM mixer (“FM-10B” manufactured by Nippon Coke Industries Co., Ltd.), 100 parts by mass of toner mother particles and 1.2 parts by mass of silica particles (Japan) under the conditions of a rotation speed of 3000 rpm and a jacket temperature of 20 ° C. "AEROSIL® RA-200H" manufactured by Aerosil Co., Ltd., dry silica particles surface-modified with trimethylsilyl group and amino group, number average primary particle size: 12 nm), and 0.8 parts by mass of conductive titanium oxide particles. (“EC-100” manufactured by Titanium Industry Co., Ltd., substrate: titanium oxide particles, coating layer: Sb-doped SnO ₂ film, medium volume diameter (D ₅₀ ): 0.35 μm) were mixed for 2 minutes. As a result, the external additive (silica particles and conductive titanium oxide particles) was adhered to the surface of the toner mother particles. Subsequently, the obtained powder was sieved using a sieve of 300 mesh (opening 48 μm). As a result, a positively charged toner TA-1 containing a large number of toner particles was obtained.

<Making toner TA-2>
In the shell layer forming step, a large number of toner particles were formed by the same procedure as for producing the toner TA-1, except that the core CA-2 of 100 parts by mass was used instead of the core CA-1 of 100 parts by mass. A positively charged toner TA-2 containing the same was obtained. The core CA-2 was obtained by the same procedure as that for producing the core CA-1, except that the screw rotation speed of the twin-screw extruder was set to 100 rpm.

<Manufacturing of toner TA-3>
In the shell layer forming step, a large number of toner particles were formed by the same procedure as for producing the toner TA-1, except that the core CA-3 of 100 parts by mass was used instead of the core CA-1 of 100 parts by mass. A positively charged toner TA-3 containing the same was obtained. Core CA-3 is core CA-3, except that 10 parts by mass of release agent RB (paraffin wax "PARACOHL-5001" manufactured by Nippon Seiro Co., Ltd.) is used instead of 10 parts by mass of release agent RA. It was obtained by the same procedure as in the preparation of 1.

<Manufacturing of toner TA-4>
In the shell layer forming step, a large number of toner particles were formed by the same procedure as for producing the toner TA-1, except that the core CA-4 of 100 parts by mass was used instead of the core CA-1 of 100 parts by mass. A positively charged toner TA-4 containing the mixture was obtained. Core CA-4 is a core CA-4, except that the screw rotation speed of the twin-screw extruder is 100 rpm and 10 parts by mass of the release agent RB is used instead of 10 parts by mass of the release agent RA. It was obtained by the same procedure as in the production of 1.

<Manufacturing of toner TB-1>
In the shell layer forming step, a large number of toner particles were formed by the same procedure as in the production of toner TA-1, except that 100 parts by mass of core CB-1 was used instead of 100 parts by mass of core CA-1. A positively charged toner TB-1 containing the mixture was obtained. The core CB-1 was obtained by the same procedure as that for producing the core CA-1, except that the screw rotation speed of the twin-screw extruder was 170 rpm.

<Making toner TB-2>
In the shell layer forming step, a large number of toner particles were formed by the same procedure as in the production of toner TA-1, except that 100 parts by mass of core CB-2 was used instead of 100 parts by mass of core CA-1. A positively charged toner TB-2 containing the mixture was obtained. Core CB-2 has core CA-, except that the screw rotation speed of the twin-screw extruder is 70 rpm and 10 parts by mass of mold release agent RB is used instead of 10 parts by mass of mold release agent RA. It was obtained by the same procedure as in the production of 1.

<Manufacturing of toner TB-3>
In the shell layer forming step, a large number of toner particles were formed by the same procedure as for producing the toner TA-1, except that the core CB-3 of 100 parts by mass was used instead of the core CA-1 of 100 parts by mass. A positively charged toner TB-3 containing the same was obtained. For the core CB-3, the screw rotation speed of the twin-screw extruder was set to 100 rpm, and instead of 10 parts by mass of the release agent RA, 10 parts by mass of the release agent RC (paraffin wax manufactured by Nippon Seiro Co., Ltd.) It was obtained by the same procedure as that for producing the core CA-1, except that NPS-6010 ”) was used.

<Manufacturing of toner TB-4>
In the shell layer forming step, a large number of toner particles were formed by the same procedure as in the production of toner TA-1, except that 100 parts by mass of core CB-4 was used instead of 100 parts by mass of core CA-1. A positively charged toner TB-4 containing the mixture was obtained. Core CB-4 has core CA-, except that the screw rotation speed of the twin-screw extruder is 70 rpm and 10 parts by mass of mold release agent RC is used instead of 10 parts by mass of mold release agent RA. It was obtained by the same procedure as in the production of 1.

<Manufacturing of toner TB-5>
In the shell layer forming step, a large number of toner particles were formed by the same procedure as for producing the toner TA-1, except that the core CB-5 of 100 parts by mass was used instead of the core CA-1 of 100 parts by mass. A positively charged toner TB-5 containing the same was obtained. The core CB-5 was obtained by the same procedure as that for producing the core CA-1, except that 10 parts by mass of the release agent RC was used instead of 10 parts by mass of the release agent RA.

<Manufacturing of toner TB-6>
In the shell layer forming step, a large number of toner particles were formed by the same procedure as for producing the toner TA-1, except that the core CB-6 of 100 parts by mass was used instead of the core CA-1 of 100 parts by mass. A positively charged toner TB-6 containing the same was obtained. Core CB-6 has core CA-, except that the screw rotation speed of the twin-screw extruder is 170 rpm and 10 parts by mass of mold release agent RC is used instead of 10 parts by mass of mold release agent RA. It was obtained by the same procedure as in the production of 1.

<Measurement method and evaluation method>
[Dispersion diameter of mold release agent domain]
After the toner to be evaluated is sufficiently dispersed in a photocurable epoxy resin (“Aronix (registered trademark) LCR D-800” manufactured by Toa Synthetic Co., Ltd.), it is irradiated with ultraviolet rays at a temperature of 40 ° C. 2 Allowed to cure for days. After curing, a slice of 250 μm in thickness was prepared by cutting the obtained cured product using a microtome set with a diamond knife. The obtained flakes were stained by exposing them to vapor of an aqueous ruthenium tetroxide solution (concentration: 0.5% by mass) on a copper mesh for 10 minutes. A cross section of the dyed flakes was photographed with a scanning electron microscope (“JSM-7401F” manufactured by JEOL Ltd.) at a magnification of 5000 times. The cross-sectional photographed image was analyzed by image analysis software (“WinROOF” manufactured by Mitani Shoji Co., Ltd.), and the dispersion diameter (diameter) of the release agent domain contained in the toner particles in the cross-sectional photographed image was measured. When the cross section of the release agent domain was not a perfect circle, the diameter equivalent to the circle (the diameter of the circle having the same area as the projected area of the release agent domain) was used as the measured value of the dispersion diameter. The dispersion diameters of 100 release agent domains in the cross-sectional image were measured, and the average number of the obtained 100 measured values was the measured value of the toner to be evaluated (dispersion diameter of the release agent domain). And said. The results are shown in Table 1. In Table 1, the "dispersion diameter" represents the dispersion diameter of the release agent domain.

[Content of mold release agent on the surface layer of toner particles]
After putting 1 g of the toner to be evaluated and 20 mL of hexane in a container, these were stirred with a stirrer for 10 minutes, and the release agent on the surface layer of the toner particles was eluted into hexane and then filtered. Then, the whole amount of the solid matter after filtration was dried in a dryer at a temperature of 40 ° C. for 12 hours. Using a differential scanning calorimeter (“DSC-6220” manufactured by Seiko Instruments Inc.), the total amount of dried solids (toner after elution with hexane) is measured from a temperature of 20 ° C to a temperature rise rate of 10 ° C / min. The operation of raising the temperature to 150 ° C. and then quenching from 150 ° C. to 20 ° C. at a temperature lowering rate of 10 ° C./min was repeated twice, and the DSC curve was measured. From the heat of fusion of the DSC curve measured in the second operation, the heat capacity of the release agent in the toner after elution with hexane was calculated. Separately, the heat capacity of the release agent in the toner was calculated in the same manner for 1 g of the toner to be evaluated that was not eluted with hexane. Then, after obtaining the exposure amount of the release agent on the surface layer of the toner particles (the amount eluted with hexane) from the difference in the heat capacity of the release agent before and after elution with hexane and the specific heat of the release agent used, the amount with respect to 1 g of the toner The ratio (mass%) of the exposure amount of the release agent on the surface layer of the toner particles was calculated. The obtained calculated value was used as the content of the release agent on the surface layer of the toner particles. The results are shown in Table 1. When the content of the release agent on the surface layer of the toner particles is 3% by mass or more and 10% by mass or less, the aggregation of the toner during storage is suppressed and the hot offset resistance tends to be excellent.

[Ratio of exposed area of mold release agent domain]
The toner matrix particles used to prepare the toner to be evaluated were exposed on a copper mesh in the steam of an aqueous ruthenium tetroxide solution (concentration: 0.5% by mass) for 10 minutes for staining. Subsequently, the surface of the dyed toner matrix particles was photographed at a magnification of 50,000 times using a transmission electron microscope (TEM) (“JSM-6700F” manufactured by JEOL Ltd.). The obtained TEM image (surface photographed image of the toner matrix particles) was analyzed using image analysis software (“WinROOF” manufactured by Mitani Shoji Co., Ltd.) to measure the exposure area ratio of the release agent domain. Specifically, in the TEM image (surface photographed image of the toner matrix particles), the ratio of the area where the release agent domain was exposed without being covered by the shell layer was measured in the surface area of the core. For each of the 100 toner mother particles in the TEM image, the exposed area ratio of the release agent domain was measured, and the average number of the obtained 100 measured values was the measured value of the toner to be evaluated (release). The ratio of the exposed area of the agent domain). The results are shown in Table 1. When the exposed area ratio of the release agent domain is 10% or more and 20% or less, the agglutination of the toner during storage tends to be suppressed and the hot offset resistance tends to be excellent. The exposed area ratio of the release agent domain can also be measured by observing and analyzing the surface of the toner matrix particles after removing the external additive from the toner to be evaluated in the same manner as described above.

[Toner cohesion]
20 g of the toner to be evaluated was placed in a polyethylene container having a capacity of 20 mL, and a stress of 0.01 kgf / mm ² was applied to the toner. Then, with a stress of 0.01 kgf / mm ² applied to the toner in the container, the container was allowed to stand in a constant temperature bath set at 25 ° C. for 3 hours. After standing for 3 hours, the toner was taken out from the constant temperature bath and used as the evaluation toner.

The obtained evaluation toner was placed on a sieve having a known mass of 200 mesh (opening 75 μm). Then, the mass of the sieve containing the evaluation toner was measured, and the mass of the toner on the sieve (the mass of the toner before sieving) was obtained. Subsequently, the above sieve is set in the powder characteristic evaluation device (“Powder Tester (registered trademark)” manufactured by Hosokawa Micron Co., Ltd.), and the sieve is vibrated for 30 seconds under the condition of Leostud scale 5 according to the manual of the powder property evaluation device. The evaluation toner was sieved. After sieving, the mass of the toner that did not pass through the sieve (toner remaining on the sieve) was measured. Then, based on the mass of the toner before sieving and the mass of the toner after sieving (the mass of the toner that did not pass through the sieving), the degree of toner aggregation (unit: mass%) was obtained according to the following formula. It was. The results are shown in Table 1.
Toner cohesion = 100 x mass of toner after sieving / mass of toner before sieving

If the toner agglutination degree is 20% by mass or less, it is evaluated as "the toner agglutination during storage is suppressed (good)", and if the toner agglutination degree is more than 20% by mass, "the toner during storage is suppressed". Aggregation is not suppressed (not good) ".

[Hot offset resistance]
100 parts by mass of a carrier for a developer (carrier for a printer "FS-C5200DN" manufactured by Kyocera Document Solutions Co., Ltd.) and 5 parts by mass of a toner to be evaluated are mixed for 30 minutes using a ball mill to prepare a two-component developer. Prepared.

As the evaluation machine, a printer equipped with a Roller-Roller type heating and pressurizing type fixing device (an evaluation machine in which the fixing temperature can be changed by modifying "FS-C5250DN" manufactured by Kyocera Document Solutions Co., Ltd.) was used. The two-component developer containing the toner to be evaluated prepared as described above was put into the developing apparatus for black of the evaluation machine, and the toner to be evaluated was put into the toner container for black of the evaluation machine.

In an environment of temperature 23 ° C. and humidity 50% RH, the amount of toner loaded on the evaluation sheet (Mondy's "ColorCopy (registered trademark)", A4 size, basis weight 90 g / m ² ) using the above evaluation machine. A black solid image (specifically, an unfixed toner image) having a size of 25 mm × 25 mm was formed under the condition of 3 mg / cm ² . Subsequently, the evaluation sheet on which the image was formed was passed through the fixing device of the evaluation machine. At this time, while raising the fixing temperature of the fixing device by 2 ° C. from 150 ° C., the presence or absence of hot offset was visually confirmed for each fixing temperature, and the maximum temperature at which hot offset did not occur (maximum fixing temperature) was measured. The presence or absence of hot offset was determined based on whether or not there was dirt (dirt that appears at each rotation cycle of the fixing roller) due to the adhesion of toner to the fixing roller on the evaluation paper. The results are shown in Table 1.

When the maximum fixing temperature was 200 ° C. or higher, it was evaluated as "high hot offset resistance (good)", and when the maximum fixing temperature was less than 200 ° C., it was evaluated as "low hot offset resistance (not good)". ..

In the toners TA-1 to TA-4, the core of the toner particles contained a polyester resin. As shown in Table 1, the acid value of the release agent contained in each core of the toners TA-1 to TA-4 was 4 mgKOH / g or less. As shown in Table 1, the dispersion diameter of the release agent domain contained in each core of the toners TA-1 to TA-4 was 300 nm or more and 700 nm or less. In the toners TA-1 to TA-4, the shell layer of the toner particles contained a monomer polymer containing the compound (1).

As shown in Table 1, the toners TA-1 to TA-4 had a toner cohesion degree of 20% by mass or less. Therefore, the toners TA-1 to TA-4 suppressed the aggregation of the toner during storage. As shown in Table 1, the toners TA-1 to TA-4 had a maximum fixing temperature of 200 ° C. or higher. Therefore, the toners TA-1 to TA-4 were excellent in hot offset resistance.

As shown in Table 1, the acid value of the release agent contained in each core of the toners TB-3 to TB-6 exceeded 4 mgKOH / g. As shown in Table 1, the dispersion diameter of the release agent domain contained in each core of the toners TB-1 and TB-6 was less than 300 nm. As shown in Table 1, the dispersion diameter of the release agent domain contained in each core of the toners TB-2 and TB-4 exceeded 700 nm.

As shown in Table 1, the toner TB-2 had a toner cohesion degree of more than 20% by mass. Therefore, the toner TB-2 did not suppress the aggregation of the toner during storage. As shown in Table 1, the toners TB-1 and TB-3 to TB-6 had a maximum fixing temperature of less than 200 ° C. Therefore, the toners TB-1 and TB-3 to TB-6 had low hot offset resistance.

From the above results, it was shown that the toner according to the present invention can improve the hot offset resistance while suppressing the aggregation of the toner during storage.

The toner according to the present invention can be used for forming an image in, for example, a multifunction device or a printer.

1 Toner particle 2 Core 3 Shell layer 21 Bending resin 22 Release agent domain

Claims (7)

A toner containing a plurality of toner particles including a core and a shell layer that partially covers the surface of the core.
The core contains a binder resin and a plurality of release agent domains.
The binding resin contains a polyester resin and contains
The acid value of the release agent constituting the release agent domain is 4 mgKOH / g or less.
The dispersion diameter of the release agent domain is 300 nm or more and 700 nm or less.
The shell layer contains a monomer polymer containing at least a compound represented by the following formula (1) .
Of the surface area of the core, the area ratio of the area where the release agent domain is not covered by the shell layer and is exposed is 10% or more and 20% or less.
The release agent constituting the release agent domain is a toner , which is a paraffin wax .

(In the above formula (1), R ¹ represents a hydrogen atom or an alkyl group which may have a substituent.) The toner according to claim 1, wherein the acid value of the binder resin is 10 mgKOH / g or more and 40 mgKOH / g or less. The toner according to claim 1 or 2 , wherein the binder resin contains a non-crystalline polyester resin as the polyester resin. The toner according to claim 3 , wherein the non-crystalline polyester resin is a polymer of a monomer containing 1,2-propanediol and terephthalic acid derived from a plant. The toner according to claim 3 or 4 , wherein the binder resin further contains a crystalline polyester resin as the polyester resin. The toner according to claim 5 , wherein the crystalline polyester resin is a polymer of a monomer containing 1,6-hexanediol and 1,10-decandicarboxylic acid. The toner according to any one of claims 1 to 6 , which is a positively charged toner.

Images