JP6935323B2 - Toner manufacturing method - Google Patents

Description

The present invention relates to a method for producing toner used for developing a latent image formed by an electrophotographic method, an electrostatic recording method, an electrostatic printing method, or the like.

As the alcohol component of the polyester resin used as the binder resin for toner, the use of so-called non-bis alcohols such as 1,2-propanediol has been studied in place of the alkylene oxide adduct of bisphenol A, which has been widely used in the past. There is.

Patent Document 1 has two or more secondary carbon atoms to which hydroxyl groups are bonded as an electrophotographic toner having excellent storage stability as well as image density under high temperature and high humidity while satisfying excellent low temperature fixability. It contains an alcohol component containing an aliphatic polyhydric alcohol (alcohol A) and at least one succinic acid derivative selected from alkyl (9 to 14 carbon atoms) succinic acid and alkenyl (9 to 14 carbon atoms) succinic acid. An electrophotographic toner containing a binder resin, which is a polycondensation resin obtained by polycondensing a carboxylic acid component, is disclosed.

In Patent Document 2, since the additive is excellent in uniform dispersibility on the surface of the matrix particles and the amount of free additive is small, the charge amount of the developer does not change, and toner filming on the photoconductor does not occur. Further, as a method for producing an electrophotographic toner in which toner filming does not occur on the developer holding member, at least the binder resin, the colorant and the mold release agent are melt-kneaded, cooled, and then pulverized and classified to obtain the parent particles. In the method for producing a toner, in which at least one or more kinds of additives are mixed to obtain a toner, the mixing of the additives comprises a two-step mixing step, and the first-step mixing step is a mother body after the classification. The particles and a part of the additive are mixed, and all the remaining additives are added and mixed in the second-stage mixing step, and the toner is mixed with respect to the parent particle measured by the ultrasonic vibration method. A method for producing an electrophotographic toner is disclosed, wherein the release rate of the additive is 1 to 7%.

Patent Document 3 describes, as a method for producing an electrostatic charge image developing toner that suppresses fog and photoconductor scratches, a method for producing an electrostatic charge image developing toner composed of toner matrix particles containing at least a binder resin and an external additive. And
Step 1: The step of mixing the toner mother particles and the external additive A, and the step 2: further mixing with the external additive B are included, and the binder resin contains polyester A having a furan ring and is an external additive. A is a hydrophobic silica particle having an average particle diameter of 20 to 80 nm and a carbon content of 2.6 to 6.0% by weight, and external agent B is a hydrophobic silica particle having an average particle diameter of 6 nm or more and less than 20 nm. A method for producing a toner for developing an electrostatic charge image in which the difference between the average particle size of the external additive B and that of the external additive B is 10 nm or more is disclosed, and 1,2-propanediol is used for the polyester A.

Japanese Unexamined Patent Publication No. 2010-107669 Japanese Unexamined Patent Publication No. 2011-2557 Japanese Unexamined Patent Publication No. 2013-205609

Although the toner described in Patent Document 1 has good low-temperature fixability, further improvement in durability is desired.

The present invention relates to a method for producing a toner having excellent low temperature fixability and durability.

The present invention is a method for producing a toner, which comprises an external addition step of mixing toner particles containing at least a binder resin and a colorant with an external additive, wherein the binder resin is a hydroxyl group bonded to a secondary carbon atom. Polyester obtained by polycondensing an alcohol component containing an aliphatic diol having 3 or more and 5 or less carbon atoms and a carboxylic acid component containing a succinic acid derivative substituted with a hydrocarbon group having 8 or more and 20 or less carbon atoms. It contains a resin, and the external addition step consists of at least two steps, and the first step is expressed by the formula (1):

The present invention relates to a method for producing toner, which is carried out under the condition that the stirring Froude number (Fr) calculated from is 200 or more and 550 or less.

By the method of the present invention, a toner having excellent low temperature fixability and durability can be obtained.

The present invention is a method for producing a toner, which comprises an externalizing step of mixing toner particles with an external additive, and is an aliphatic having a hydroxyl group bonded to a secondary carbon atom having 3 to 5 carbon atoms as a binder resin. This is a method for obtaining a toner having excellent low-temperature fixability and durability by performing an external addition step in multiple steps under predetermined conditions using a polyester resin obtained by using a diol.

When the present inventors observed the state of the toner containing the polyester resin using 1,2-propanediol after printing resistance, the outside of the toner surface was compared with the case where the alkylene oxide adduct of bisphenol A was used. It was found that there was a large difference in the amount of the adduct attached. Therefore, as a result of investigating that the toner particles before external addition aggregated due to moisture absorption and the adhesive force of the external addition agent was weakened, a highly hydrophobic succinic acid derivative was used for the carboxylic acid component of the polyester resin. As a result, the absorption of moisture by the toner particles is suppressed, and by performing the external addition step in multiple stages, the aggregation of the toner particles can be sufficiently suppressed by the external addition step of the first stage, and the aggregation of the toner particles can be sufficiently suppressed in the second and subsequent stages. The adhesive force of the external additive added in the external addition process was strengthened, and the durability of the toner could be improved.

The toner particles may be produced by any conventionally known method such as a melt-kneading method, an emulsification phase inversion method, or a polymerization method, but from the viewpoint of productivity and dispersibility of the colorant, the melt-kneading method is used. Grinding toner is preferable. Therefore, the toner particles in the present invention are preferably produced by a method including a kneading step of melt-kneading the binder resin and the colorant and a crushing step of pulverizing the obtained kneaded product.

The kneading step is a step of melt-kneading at least the binder resin and the colorant.

The binder resin is an alcohol component containing an aliphatic diol having 3 to 5 carbon atoms having a hydroxyl group bonded to a secondary carbon atom, and a succinic acid derivative substituted with a hydrocarbon group having 8 to 20 carbon atoms. It contains a polyester resin obtained by polycondensing with the contained carboxylic acid component.

In the alcohol component, examples of the aliphatic diol having a hydroxyl group bonded to a secondary carbon atom and having 3 or more and 5 or less carbon atoms include 1,2-propanediol, 1,2-butanediol, 1,3-butanediol, and 2. , 3-Butanediol and the like, and among these, 1,2-propanediol is preferable from the viewpoint of low-temperature fixability.

The content of an aliphatic diol having a hydroxyl group bonded to a secondary carbon atom and having 3 or more and 5 or less carbon atoms is 40 mol% or more, preferably 50 mol, in the alcohol component from the viewpoint of low temperature fixability and heat storage stability. % Or more, more preferably 55 mol% or more, still more preferably 60 mol% or more, and 100 mol% or less, preferably 95 mol% or less, more preferably 90 mol% or less, still more preferably 85 mol% or less. Is.

From the viewpoint of low-temperature fixability and heat-resistant storage, the alcohol component preferably contains an α, ω-linear alkanediol having 2 or more and 4 or less carbon atoms as a short-chain aliphatic diol.

Examples of α, ω-linear alkanediol having 2 or more and 4 or less carbon atoms include ethylene glycol, 1,3-propanediol, and 1,4-butanediol. Among these, from the viewpoint of low-temperature fixability. , 1,4-Butanediol is preferred.

The content of α, ω-linear alkanediol having 2 or more and 4 or less carbon atoms is preferably 5 mol% or more, more preferably 10 mol% or more, still more preferably 15 mol% or more, and more preferably 15 mol% or more in the alcohol component. From the viewpoint of storage stability, it is preferably 50 mol% or less, more preferably 45 mol% or less, still more preferably 40 mol% or less.

In addition, the molar ratio of an aliphatic diol having a hydroxyl group bonded to a secondary carbon atom and having a carbon number of 3 to 5 and an α, ω-linear alkane diol having a carbon number of 2 to 4 is (bonded to a secondary carbon atom). The aliphatic diol / α, ω-linear alkanediol) having a hydroxyl group is preferably 50/50 or more, more preferably 55/45 or more, still more preferably 60/40 or more, from the viewpoint of heat storage stability. From the viewpoint of low temperature fixability, it is preferably 95/5 or less, more preferably 90/10 or less, and further preferably 85/15 or less.

Examples of other alcohol components include aromatic diols such as alkylene oxide adducts of bisphenol A, aliphatic diols having 6 or more carbon atoms, and trihydric or higher alcohols such as glycerin.

The hydrocarbon group in the succinic acid derivative substituted with a hydrocarbon group contained in the carboxylic acid component is preferably an alkyl group or an alkenyl group. Therefore, specific examples of the succinic acid derivative substituted with a hydrocarbon group include dodecyl succinic acid, dodecenyl succinic acid, tetrapropenyl succinic acid, decenyl succinic acid, their acid anhydrides, and alkyl having 1 or more and 3 or less carbon atoms. Esters and the like can be mentioned. Among them, dodecenyl succinic acid, tetrapropenyl succinic acid, or acid anhydrides thereof are preferable, and dodecenyl succinic anhydride is more preferable, from the viewpoint of heat-resistant storage stability.

From the viewpoint of hydrophobicity, the number of carbon atoms of the hydrocarbon group in the succinic acid derivative is 8 or more, preferably 10 or more, more preferably 12 or more, and 20 or less, preferably 18 or less, more preferably. Is 16 or less.

Therefore, the succinic acid derivative is selected from the group consisting of succinic acid substituted with an alkyl group having 10 or more and 18 or less carbon atoms and succinic acid substituted with an alkenyl group having 10 or more and 18 or less carbon atoms from the viewpoint of hydrophobicity. At least one or two or more are preferable, and at least selected from the group consisting of succinic acid substituted with an alkyl group having 12 or more and 16 or less carbon atoms and succinic acid substituted with an alkenyl group having 12 or more and 16 or less carbon atoms. One type or two or more types are more preferable.

The content of the succinic acid derivative is preferably 3 mol% or more, more preferably 5 mol% or more, still more preferably 10 mol% or more, and heat-resistant storage stability in the carboxylic acid component from the viewpoint of hydrophobicity. From the viewpoint, it is preferably 50 mol% or less, more preferably 40 mol% or less, still more preferably 30 mol% or less, still more preferably 25 mol% or less.

Examples of the divalent carboxylic acid compound other than the succinic acid derivative include, for example, a dicarboxylic acid having 3 or more and 30 or less carbon atoms, more preferably 3 or more and 20 or less carbon atoms, and further preferably 3 or more and 10 or less carbon atoms. Examples thereof include acid anhydrides thereof and derivatives such as alkyl esters having 1 or more and 3 or less carbon atoms. Specifically, an aromatic dicarboxylic acid compound or an aliphatic dicarboxylic acid compound is preferable, and an aromatic dicarboxylic acid compound is more preferable from the viewpoint of durability. Examples of the aromatic dicarboxylic acid include phthalic acid, isophthalic acid, terephthalic acid and the like, and among these, terephthalic acid is preferable. Examples of the aliphatic dicarboxylic acid include fumaric acid, maleic acid, succinic acid, glutaric acid, adipic acid, sebacic acid and the like. In the present specification, the carboxylic acid compound includes an ester of a carboxylic acid, a carboxylic acid and an alcohol having 1 or more and 3 or less carbon atoms, and an acid anhydride.

The content of the aromatic dicarboxylic acid compound is preferably 40 mol% or more, more preferably 60 mol% or more in the carboxylic acid component from the viewpoint of durability and heat storage stability, and from the viewpoint of low temperature fixability. Therefore, it is preferably 95 mol% or less, more preferably 85 mol% or less.

Examples of the trivalent or higher carboxylic acid compound include a trivalent or higher carboxylic acid having 4 or more and 30 or less carbon atoms, more preferably 4 or more and 20 or less carbon atoms, and further preferably 4 or more and 10 or less carbon atoms. Examples thereof include acid anhydrides thereof and derivatives such as alkyl esters having 1 or more and 3 or less carbon atoms. Specifically, 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, 1,2,4,5-benzenetetracarboxylic acid (pyromellitic acid) or theirs. Examples thereof include acid anhydrides, and from the viewpoint of improving durability and charge stability, 1,2,4-benzenetricarboxylic acid (trimellitic acid) or an acid anhydride thereof is preferable, and 1,2,4-benzenetricarboxylic acid is preferable. Acid anhydrides (trimellitic anhydride) are more preferred.

The content of the trivalent or higher carboxylic acid compound is preferably 0.5 mol% or more, more preferably 1 mol% or more, and low-temperature fixability in the carboxylic acid component from the viewpoint of durability and heat storage stability. From the above viewpoint, it is preferably 15 mol% or less, more preferably 10 mol% or less.

The alcohol component may contain a monovalent alcohol, and the carboxylic acid component may contain a monovalent carboxylic acid compound as appropriate.

The equivalent ratio (COOH group / OH group) of the carboxylic acid component to the alcohol component in the polyester resin is preferably 0.6 or more, more preferably 0.7 or more, still more preferably 0.75 or more, and preferably 1.2 or less, more preferably. Is less than or equal to 1.15.

The polyester resin preferably contains, for example, an alcohol component and a carboxylic acid component in an inert gas atmosphere, preferably in the presence of an esterification catalyst, and if necessary, in the presence of an esterification co-catalyst, a polymerization inhibitor, or the like. It can be produced by polycondensation at a temperature of 130 ° C. or higher, more preferably 170 ° C. or higher, and preferably 250 ° C. or lower, more preferably 240 ° C. or lower.

Examples of the esterification catalyst include tin compounds such as dibutyltin oxide and tin (II) 2-ethylhexanoate, and titanium compounds such as titanium diisopropyrate bistriethanol aminated, and tin compounds are preferable. The amount of the esterification catalyst used is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, and preferably 1.5 parts by mass or less, based on 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. It is preferably 1 part by mass or less. Examples of the esterification co-catalyst include gallic acid and the like. The amount of the esterification co-catalyst used is preferably 0.001 part by mass or more, more preferably 0.01 part by mass or more, and preferably 0.5 part by mass or less, based on 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. More preferably, it is 0.1 part by mass or less. Examples of the polymerization inhibitor include t-butylcatechol and the like. The amount of the polymerization inhibitor used is preferably 0.001 part by mass or more, more preferably 0.01 part by mass or more, and preferably 0.5 part by mass or less, based on 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. It is preferably 0.1 parts by mass or less.

In the present invention, the polyester resin may be a polyester resin modified to such an extent that its characteristics are not substantially impaired. Examples of the modified polyester resin include grafting and blocking with phenol, urethane, epoxy and the like by the methods described in JP-A-11-133668, JP-A-10-239903, JP-A-8-20636 and the like. Examples of the modified polyester resin include a modified polyester resin, and among the modified polyester resins, a urethane-modified polyester resin obtained by urethane-extending the polyester resin with a polyisocyanate compound is preferable.

The softening point of the polyester resin is preferably 110 ° C. or higher, more preferably 120 ° C. or higher from the viewpoint of storage stability, and preferably 150 ° C. or lower, more preferably 140 ° C. or lower from the viewpoint of low-temperature fixability. Is.

The glass transition temperature of the polyester resin is preferably 40 ° C. or higher, more preferably 50 ° C. or higher from the viewpoint of storage stability, and preferably 80 ° C. or lower, more preferably 70 ° C. or higher from the viewpoint of low temperature fixability. It is as follows.

From the viewpoint of hygroscopicity, the acid value of the polyester resin is preferably 20 mgKOH / g or less, more preferably 15 mgKOH / g or less.

As the binder resin, other known resins other than the polyester resin, such as other polyester resins, vinyl resins such as styrene-acrylic resin, epoxy resins, polycarbonates, polyurethanes, etc., as long as the effects of the present invention are not impaired. The resin may be used in combination, but the content of the polyester resin is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, still more preferably 100% by mass. ..

As the colorant, dyes, pigments, magnetic substances and the like used as colorants for toner can be used. For example, carbon black, phthalocyanine blue, permanent brown FG, brilliant first scarlet, pigment green B, rhodamine-B base, solvent red 49, solvent red 146, solvent blue 35, quinacridone, carmin 6B, isoindoline, disazoero, etc. .. In the present invention, the toner particles may be either black toner or color toner.

The amount of the colorant used is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and preferably 40 parts by mass with respect to 100 parts by mass of the binder resin from the viewpoint of improving the image density of the toner. Parts or less, more preferably 20 parts by mass or less, still more preferably 10 parts by mass or less.

In addition to binder resins and colorants, as raw materials for melt-kneading, mold release agents, charge control agents, magnetic powders, fluidity improvers, conductivity modifiers, reinforcing fillers such as fibrous substances, antioxidants, etc. Additives such as a cleanability improver may be used.

As the release agent, hydrocarbon waxes such as polypropylene wax, polyethylene wax, polypropylene polyethylene copolymer wax, microcrystallin wax, paraffin wax, Fishertropch wax, and sazole wax and their oxides; carnauba wax, montane. Waxes and ester waxes such as deoxidized waxes and fatty acid ester waxes; fatty acid amides, fatty acids, higher alcohols, fatty acid metal salts and the like can be mentioned, and these can be used alone or in combination of two or more. Among these, carnauba wax is preferable from the viewpoint of durability.

The melting point of the release agent is preferably 60 ° C. or higher, more preferably 70 ° C. or higher from the viewpoint of toner transferability, and preferably 160 ° C. or lower, more preferably 150 ° C. or higher from the viewpoint of low temperature fixability. It is as follows.

The amount of the release agent used is preferably 0.5 parts by mass or more with respect to 100 parts by mass of the binder resin from the viewpoint of low temperature fixability and offset resistance of the toner and dispersibility in the binder resin. It is preferably 1 part by mass or more, and preferably 10 parts by mass or less, more preferably 8 parts by mass or less, and further preferably 7 parts by mass or less.

The charge control agent is not particularly limited, and may contain either a positive charge control agent or a negative charge control agent.

Positive charge control agents include niglosin dyes such as "niglosin base EX", "oil black BS", "oil black SO", "bontron N-01", "bontron N-04", and "bontron N-07". , "Bontron N-09", "Bontron N-11" (all manufactured by Orient Chemical Industry Co., Ltd.), etc .; Triphenylmethane dyes containing tertiary amines as side chains, quaternary ammonium salt compounds, for example. "Bontron P-51" (manufactured by Orient Chemical Industry Co., Ltd.), cetyltrimethylammonium bromide, "COPY CHARGE PX VP435" (manufactured by Clariant), etc .; (Manufactured), etc .; imidazole derivatives such as "PLZ-2001", "PLZ-8001" (all manufactured by Shikoku Kasei Kogyo Co., Ltd.), etc .; styrene-acrylic resin, for example "FCA-701PT" (Fujikura Kasei Co., Ltd.) (Manufactured) and the like.

As the negative charge control agent, metal-containing azo dyes such as "Varifast Black 3804", "Bontron S-31", "Bontron S-32", "Bontron S-34", and "Bontron S-36" (Above, manufactured by Orient Chemical Industry Co., Ltd.), "Eisenspiron Black TRH", "T-77" (manufactured by Hodoya Chemical Industry Co., Ltd.), etc .; Metal compounds of benzylic acid compounds, for example, "LR-" 147 ”,“ LR-297 ”(above, manufactured by Nippon Carlit Co., Ltd.); metal compounds of salicylic acid compounds, for example,“ Bontron E-81 ”,“ Bontron E-84 ”,“ Bontron E-88 ”,“ Bontron E-304 "(above, manufactured by Orient Chemical Industry Co., Ltd.)," TN-105 "(manufactured by Hodoya Chemical Industry Co., Ltd.), etc .; copper phthalocyanine dye; quaternary ammonium salt, for example," COPY CHARGE NX VP434 " (Manufactured by Clariant), nitroimidazole derivatives, etc .; organic metal compounds and the like can be mentioned.

From the viewpoint of the charge stability of the toner, the amount of the charge control agent used is preferably 0.01 part by mass or more, more preferably 0.2 part by mass or more, and preferably 10 parts by mass with respect to 100 parts by mass of the binder resin. Parts or less, more preferably 5 parts by mass or less, still more preferably 3 parts by mass or less, still more preferably 2 parts by mass or less.

The raw materials to be subjected to melt-kneading containing at least the binder resin and the colorant may be subjected to kneading at once or divided and subjected to kneading, but they may be mixed in advance with a mixer such as a Henschel mixer or a ball mill and then kneaded. It is preferable to supply it to the machine.

The melt kneading can be performed by using a known kneader such as a closed kneader, a single-screw or two-screw extruder, or an open roll type kneader.

After melt-kneading, it is preferable that the kneaded product is appropriately cooled until it reaches a hardness that can be pulverized, and a pulverization step and, if necessary, a classification step are performed to obtain toner particles. Here, cooling means cooling the kneaded product to 0 ° C. or higher and 50 ° C. or lower, or cooling the kneaded product to a glass transition temperature or lower of the binder resin in the kneaded product.

The pulverization step is a step of pulverizing the obtained kneaded product to obtain toner particles. The kneaded product may be pulverized at once or stepwise to a desired particle size, but from the viewpoint of efficient and more uniform pulverization, it may be performed in two stages of coarse pulverization and fine pulverization. preferable.

Examples of the crusher used for coarse crushing include a hammer mill, an atomizer, and a Rohtoplex.

In coarse pulverization, it is preferable to pulverize until the maximum diameter becomes 3 mm or less. For a pulverized product having a maximum diameter of 3 mm or less, the kneaded product is appropriately roughly pulverized until the particle size is 0.05 mm or more and 3 mm or less, and then passed through a sieve having a mesh opening of 3 mm to obtain a pulverized product that has passed through the sieve. Can be done.

Examples of the pulverizer used for pulverization include a fluidized bed type jet mill, a jet mill such as a collision plate type jet mill, and a rotary mechanical type mill. Among these, a fluidized bed type jet mill and a collision plate type jet mill are preferable, and a collision plate type jet mill is more preferable, from the viewpoint of pulverization efficiency.

The degree of fine pulverization is preferably adjusted as appropriate according to the particle size of the target toner.

Examples of the classifying machine used in the classifying process include an air flow type classifying machine, an inertial type classifying machine, and a sieve type classifying machine.

_{The volume median particle diameter (D 50} ) of the toner particles before the external addition step is preferably 3 μm or more, more preferably 4 μm or more, and preferably 15 μm or less, more preferably 10 μm or less. In the present specification, the volume median particle size (D ₅₀ ) means a particle size in which the cumulative volume frequency calculated by the volume fraction is 50% calculated from the smaller particle size.

Subsequently, an external addition step of mixing the obtained toner particles with the external additive is performed.

Examples of the external additive include inorganic fine particles such as silica, alumina, titania, zirconia, tin oxide, and zinc oxide, and organic fine particles such as resin particles such as melamine-based resin fine particles and polytetrafluoroethylene resin fine particles. Two or more types may be used together. Among these, silica is preferable, and from the viewpoint of toner transferability, hydrophobic silica that has been hydrophobized is more preferable.

Examples of the hydrophobizing agent for hydrophobizing the surface of silica particles include hexamethyldisilazane (HMDS), dimethyldichlorosilane (DMDS), silicone oil, octylliethoxysilane (OTES), methyltriethoxysilane, and cyclic. Examples thereof include silazane, aminosilane, and octylsilane.

The average particle size of the external additive is preferably 6 nm or more, more preferably 8 nm or more, and preferably 200 nm or less, more preferably 150 nm or less, and further, from the viewpoint of toner chargeability, fluidity, and transferability. It is preferably 100 nm or less.

The external additive used may be one type, but it is preferable to combine two or more types having different average particle sizes.
For example, from the viewpoint of chargeability and fluidity, an external additive having an average particle size of preferably 6 nm or more, more preferably 8 nm or more, and preferably 30 nm or less, more preferably 15 nm or less is preferable.
From the viewpoint of transferability, an external additive having a thickness of 20 nm or more, more preferably 30 nm or more, and preferably 60 nm or less, more preferably 50 nm or less is preferable.
From the viewpoint of supply cassoulet, an external additive having a concentration of 40 nm or more, more preferably 60 nm or more, and preferably 200 nm or less, more preferably 150 nm or less, still more preferably 100 nm or less is preferable.

It is preferable to adjust the particle size and the amount of the external additive to be used according to the effect of each particle size and the target coating rate. The coverage of the toner obtained by the present invention with an external additive is preferably 70% or more, more preferably 80% or more, still more preferably 90% or more, still more preferably, from the viewpoint of improving durability and preventing supply blurring. Is 100% or more, and from the viewpoint of low temperature fixability, it is preferably 200% or less, more preferably 150% or less, still more preferably 130% or less. In the present invention, the coverage is a theoretical value calculated from the mathematical formula described in Examples described later using the average particle size and the amount of the external additive, and adheres to the toner particles after external addition. It is different from the coverage with the external additive.

The total amount of the external additive used (the amount of the external additive used in the entire external addition process) is preferably adjusted according to the target coverage, but it improves durability and prevents supply scraping. From the viewpoint, it is preferably 1 part by mass or more, more preferably 2 parts by mass or more, still more preferably 3 parts by mass or more, and preferably 10 parts by mass or less, more preferably 7 parts by mass or more with respect to 100 parts by mass of the toner particles. It is not more than parts by mass, more preferably 5 parts by mass or less.

A mixer such as a Henschel mixer can be used for mixing the toner particles and the external additive, but in the present invention, the external additive is divided and externally added to the toner particles in at least two steps. The external addition step is performed, and the first step is carried out under the condition that the number of stirring fluids is within a predetermined range. The number of agitated Froude numbers is given by Equation (1) :.

Although it is calculated from, the aggregation of toner particles can be suppressed by performing the first step with a strong stirring force, and the external additive added in the second and subsequent steps is attached to the toner particles. It is possible to significantly strengthen the wearing power.

The agitated Froude number (Fr) in the first step is 200 or more, preferably 300 or more, more preferably 400 or more, and the burial of the external additive from the viewpoint of strengthening the adhesive force of the external additive. From the viewpoint of preventing the above, it is 550 or less, preferably 530 or less, and more preferably 520 or less.

The average particle size of the external additive used in the first step is preferably 6 nm or more, more preferably 8 nm or more from the viewpoint of preventing the embedding of the external additive, and imparts fluidity to the toner. From the viewpoint of suppressing particle aggregation, it is preferably 100 nm or less, more preferably 50 nm or less, still more preferably 20 nm or less, still more preferably 10 nm or less.

The amount of the external additive used in the first step is preferably adjusted according to the target coverage. The coverage of the toner particles by the external additive in the first step is preferably 10% or more, more preferably 15% or more, still more preferably 20% or more from the viewpoint of preventing the burial of the external additive. Then, from the viewpoint of imparting fluidity, it is preferably 60% or less, more preferably 45% or less, still more preferably 35% or less, still more preferably 30% or less.

The amount of the external additive used in the first step is preferably adjusted according to the target coverage, but from the viewpoint of preventing the external additive from being buried, 100 parts by mass of the toner particles is used. It is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, still more preferably 0.15 parts by mass or more, and preferably 5 parts by mass or less from the viewpoint of imparting fluidity and suppressing aggregation of toner particles. It is more preferably 3 parts by mass or less, further preferably 1 part by mass or less, still more preferably 0.5 parts by mass or less.

The amount of the external additive used in the first step is preferably 1.5% by mass or more, more preferably 2.5% by mass or more, still more preferably 3% by mass or more, based on the total amount used in the external addition step. It is more preferably 4% by mass or more, and preferably 75% by mass or less, more preferably 60% by mass or less, still more preferably 40% by mass or less, still more preferably 20% by mass or less, still more preferably 10% by mass or less. Is.

An external additive other than the external additive used in the first stage is mixed with the toner particles in the external addition steps of the second and subsequent stages. The external addition step may be carried out in multiple steps of three or more steps, but from the viewpoint of production efficiency, it is preferable to carry out in two steps.

The mixing conditions of the second and subsequent steps are not particularly limited, but the number of stirring fluids is preferably 200 or more, more preferably 300 or more, still more preferably 400 or more, and preferably 400 or more, as in the first step. Is 550 or less, more preferably 530 or less, still more preferably 520 or less.

The toner obtained by the method of the present invention can be used as a one-component developing toner or as a two-component developing agent by mixing with a carrier.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples. The physical properties of the resin and the like were measured by the following methods.

[Resin softening point]
Using the flow tester "CFT-500D" (manufactured by Shimadzu Corporation), while heating a 1 g sample at a heating rate of 6 ° C / min, a load of 1.96 MPa was applied by a plunger, and the diameter was 1 mm and the length was 1 mm. Push out from the nozzle. The amount of plunger drop of the flow tester is plotted against the temperature, and the temperature at which half of the sample flows out is used as the softening point.

[Resin glass transition temperature]
Using the differential scanning calorimeter "Q-20" (manufactured by TA Instruments Japan Co., Ltd.), weigh 0.01 to 0.02 g of the sample in an aluminum pan, raise the temperature to 200 ° C, and then use that temperature. Cool to 0 ° C at a temperature lowering rate of 10 ° C / min. Next, the sample is heated at a heating rate of 10 ° C./min, and the endothermic peak is measured. The temperature at the intersection of the extension of the baseline below the maximum peak temperature of heat absorption and the tangent line indicating the maximum slope from the rising portion of the peak to the peak of the peak is defined as the glass transition temperature.

[Acid value of resin]
Measure based on the method of JIS K 0070. However, only the measurement solvent is changed from the mixed solvent of ethanol and ether specified in JIS K0070 to the mixed solvent of acetone and toluene (acetone: toluene = 1: 1 (volume ratio)).

[Melting point of mold release agent]
Using the differential scanning calorimeter "DSC Q20" (manufactured by TA Instruments Japan Co., Ltd.), weigh 0.01 to 0.02 g of the sample in an aluminum pan, and heat up to 200 ° C at a temperature rise rate of 10 ° C / min. The temperature is raised and cooled from that temperature to -10 ° C at a temperature lowering rate of 5 ° C / min. Next, the sample is heated to 180 ° C. at a heating rate of 10 ° C./min and measured. The maximum peak temperature of the endothermic observed from the melted endothermic curve obtained there is taken as the melting point of the mold release agent.

[Volume medium particle size of toner particles (D ₅₀ )]
Measuring machine: Coulter Multisizer II (manufactured by Beckman Coulter Co., Ltd.)
Aperture diameter: 100 μm
Analysis software: Coulter Multisizer AccuComp version 1.19 (manufactured by Beckman Coulter Co., Ltd.)
Electrolyte: Isoton II (manufactured by Beckman Coulter Co., Ltd.)
Dispersion solution: Emulgen 109P (manufactured by Kao Co., Ltd., polyoxyethylene lauryl ether, HLB (griffin): 13.6) was dissolved in an electrolytic solution to adjust to 5% by mass. Was added and dispersed with an ultrasonic disperser (machine name: US-1, manufactured by SND Co., Ltd., output: 80 W) for 1 minute, then 25 mL of the electrolytic solution was added, and the mixture was further added to the ultrasonic disperser. Disperse for 1 minute to prepare a sample dispersion.
Measurement conditions: To 100 mL of the electrolytic solution, add the sample dispersion so that the particle size of 30,000 particles can be measured in 20 seconds, measure 30,000 particles, and measure the volume from the particle size distribution. Determine the medium particle size (D ₅₀ ).

[Average particle size of external additive]
The average particle size refers to the number average particle size, and the particle size (average value of major axis and minor axis) of 500 particles is measured from a scanning electron microscope (SEM) photograph and used as the average value of the numbers.

[Coverage of external additive]
Calculate from the following formula.
Coverage (%) = √3 / 2π × (D ・ ρt) / (d ・ ρs) × C × 100
(In the formula, D is the volume median particle size (D ₅₀ ) (μm) of the toner particles before the external addition step, d is the average particle size (μm) of the external additive, ρt is the specific gravity of the toner particles, and ρs is the outside. Specific gravity of additive, C indicates the mass ratio of toner particles to external additive (external / toner particles))
The total coverage of the external additives shall be the sum of the coverage calculated for each external additive. In all the examples and comparative examples, the specific gravity of the toner particles is 1.2 and the specific density of silica is 2.2.

Resin production example 1
Place the raw material monomers other than trimellitic anhydride and the esterification catalyst shown in Table 1 in a 10 L four-necked flask equipped with a thermometer, a stainless stir bar, a flow-down condenser and a nitrogen introduction tube, and place them in a nitrogen atmosphere. After raising the temperature to 180 ° C. in a mantle heater, the temperature was raised to 230 ° C. over 5 hours. Then, the reaction was carried out at 230 ° C. and 8.0 kPa for 1 hour, cooled to 210 ° C., and trimellitic anhydride shown in Table 1 was added. After the reaction was carried out at normal pressure for 1 hour, the reaction was carried out at 40 kPa until a desired softening point was reached to obtain polyester resins (PES-1, PES-2). Table 1 shows the physical characteristics of the obtained resin.

Resin production example 2
Place the raw material monomers other than trimellitic anhydride shown in Table 1, the esterification catalyst, and the polymerization inhibitor into a 10 L four-necked flask equipped with a thermometer, a stainless stir bar, a flow-down condenser, and a nitrogen introduction tube. The temperature was raised to 230 ° C. in a mantle heater in a nitrogen atmosphere, and the reaction was carried out for 5 hours. Then, the reaction was carried out at 230 ° C. and 8.0 kPa for 1 hour, cooled to 210 ° C., and trimellitic anhydride shown in Table 1 was added. After the reaction was carried out at normal pressure for 1 hour, the reaction was carried out at 40 kPa until a desired softening point was reached to obtain a polyester resin (PES-3). Table 1 shows the physical characteristics of the obtained resin.

Examples 1, 3 to 8 and Comparative Examples 3, 5 (Examples 5 and 6 are reference examples)
100 parts by mass of binder resin shown in Table 2, 5.0 parts by mass of colorant "REGAL 330R" (manufactured by Cabot Specialty Chemicals, Inc.), mold release agent "NP-055" (manufactured by Mitsui Chemicals, Inc., polypropylene) Wax, melting point: 146 ° C) 1.0 part by mass, and charge control agent "Bontron E-304" (manufactured by Orient Chemical Industry Co., Ltd.) 1.0 part by mass are mixed for 1 minute using a Henshell mixer, and then under the conditions shown below. It was melt-kneaded.

A biaxially rotating twin-screw extruder "PCM-30" (manufactured by Ikegai Co., Ltd., shaft diameter 2.9 cm, shaft cross-sectional area 7.06 cm ² ) was used. The operating conditions are barrel set temperature 100 ℃, shaft rotation speed 200r / min (peripheral speed of shaft rotation 0.30m / s), mixture supply speed 10kg / h (mixture supply amount per unit cross-sectional area of shaft 1.42kg / h).・ It was ^{cm 2).}

The obtained resin kneaded product is cooled, roughly crushed by a crusher "Rotoplex" (manufactured by Hosokawa Micron Co., Ltd.), and a coarsely crushed product having a medium volume particle size of 2 mm or less is prepared using a sieve having a mesh size of 2 mm. Obtained. The obtained coarse pulverized product is finely pulverized by adjusting the pulverization pressure so that the volume median particle diameter is 6.5 μm using a collision plate type jet mill crusher IDS-2 type (manufactured by Nippon Pneumatic Co., Ltd.). bottom. The obtained finely pulverized material is classified using a DSX-2 type airflow classifier (manufactured by Nippon Pneumatic Co., Ltd.) by adjusting the static pressure (internal pressure) so that the volume median particle size is 7.5 μm. To obtain toner particles.

The external additive (first stage) shown in Table 2 was added to 100 parts by mass of the obtained toner particles, and a peripheral speed of 32 m was used using a Henschel mixer (manufactured by Nippon Coke Industries Co., Ltd., diameter of stirring blade 0.206 m). / s (Mixed at a rotation speed of 3000 r / min for 3 minutes. Next, the external additive (second stage) shown in Table 2 was further added, and a peripheral speed of 32 m / s (rotation speed 3000 r / min) was used using a Henschel mixer. Was mixed for 3 minutes to obtain toner.

Example 2
Toner was added in the same manner as in Example 1 except that the external additive (first stage) shown in Table 2 was added and mixed at a peripheral speed of 23 m / s (rotation speed 2100 r / min for 3 minutes) using a Henschel mixer. Obtained.

Comparative Examples 1 and 2
Add the external additive (first stage) shown in Table 2 to 100 parts by mass of the toner particles, mix for 3 minutes at a peripheral speed of 32 m / s (rotation speed 3000 r / min) using a Henschel mixer, and outside the second stage. Toner was obtained in the same manner as in Example 1 except that the addition step was not performed.

Comparative Example 4
Toner was added in the same manner as in Example 1 except that the external additive (first stage) shown in Table 2 was added and mixed at a peripheral speed of 16 m / s (rotation speed 1500 r / min for 3 minutes) using a Henschel mixer. Obtained.

Reference example 1
Add the external additive (first stage) shown in Table 2 to 100 parts by mass of the toner particles, mix for 3 minutes at a peripheral speed of 32 m / s (rotation speed 3000 r / min) using a Henschel mixer, and outside the second stage. Toner was obtained in the same manner as in Comparative Example 5 except that the addition step was not performed.

Test Example 1 [Low temperature fixability]
The printer "HL-2040" (manufactured by Brother Industries, Ltd.), which was modified to take unfixed images, was filled with toner and a 2 cm square solid image was printed. Using an external fixing device modified from "OKI MICROLINE 3010" (manufactured by Oki Data Corporation), the temperature of the fixing roll is raised by 5 ° C from 100 ° C to 230 ° C at a rotation speed of 180 mm / s. This unfixed image was fixed at each temperature to obtain a fixed image. The images obtained at each fixing temperature are rubbed 5 times with a sand eraser (ER-502R, manufactured by Lion Office Products Co., Ltd.) under a load of 400 g, and the image density before and after rubbing is measured with the image density measuring device "Gretag SPM50". Measured using (Gretag Macbeth), the temperature at which the image density ratio before and after rubbing ([image density after rubbing / image density before rubbing] x 100) first exceeds 90% is set as the minimum fixing temperature, and the temperature is low. It was used as an index of fixability. The smaller the value, the better the low temperature fixability. The results are shown in Table 2.

Test Example 2 [Durability]
50 g of toner was mounted on a non-magnetic one-component developing device "HL-2040" (manufactured by Brother Industries, Ltd.), and an A4 size solid black image was printed in an environment of 25 ° C. and 50% humidity. Next, after printing 500 sheets at a printing rate of 1%, a solid black image of A4 size was printed again. J paper (trade name, manufactured by Fuji Xerox Co., Ltd.) was used as the printing medium. "Gretag SPM50" (manufactured by Gretag Macbeth) is used to set _{the image density (ID 1} ) of the central part 5 cm from the bottom of the initial black solid image _{and the image density (ID 2} ) of the central part 5 cm from the bottom after printing 500 sheets. The difference in image density between the two was confirmed. When the difference in image density exceeds 0.4, printing is terminated with the number of printed sheets as supply blurring, and when it does not exceed 0.4, another 500 sheets are printed and printed until supply blurring occurs. The larger the number of prints, the better the durability. The results are shown in Table 2.

From the above results, the toners obtained in Examples 1 to 8 have good low-temperature fixability and durability.
On the other hand, in Comparative Example 1 in which the external addition step was performed in one step, the durability was insufficient, which is presumed to be due to insufficient adhesion of the external additive in the one-step external addition. , As in Comparative Example 2, when the amount of the external additive used is increased, the durability is improved, but the low temperature fixability is deteriorated, and even if the external addition step is performed in two steps as in Comparative Example 4. If the stirring Froude number is too small, the durability will be poor. Further, in Comparative Example 3 using the polyester resin which does not use the succinic acid derivative, both the low temperature fixability and the durability are deteriorated.
Further, from the comparison between Comparative Example 5 and Reference Example 1, when the polyester resin using the alkylene oxide adduct of bisphenol A was used, both the low temperature fixability and the durability were good in the one-step externaling step. While toner is obtained, the durability is rather deteriorated by performing the external addition process in multiple stages. This is because the toner particles containing the polyester resin using the alkylene oxide adduct of bisphenol A are difficult to aggregate, so that the external additive adheres to the toner particles moderately in the one-step externalizing step, whereas it adheres to the toner particles in two steps. It is presumed that this is due to the excessive embedding of the external additive. Therefore, the effect of the present invention in which durability is improved by performing the external addition step in multiple steps is a polyester resin using an aliphatic diol having a hydroxyl group bonded to a secondary carbon atom such as 1,2-propanediol. It can be seen that this is an effect peculiar to the toner using.

The toner obtained by the method of the present invention is suitably used for developing a latent image formed by an electrostatic charge image developing method, an electrostatic recording method, an electrostatic printing method, or the like.

Claims (4)

A method for producing a toner, which comprises an external addition step of mixing toner particles containing at least a binder resin and a colorant with an external additive, wherein the binder resin has a number of carbon atoms having a hydroxyl group bonded to a secondary carbon atom. Contains a polyester resin obtained by polycondensing an alcohol component containing an aliphatic diol of 3 or more and 5 or less and a carboxylic acid component containing a succinic acid derivative substituted with a hydrocarbon group having 8 or more and 20 or less carbon atoms. , The external addition process consists of at least two steps, and the first step is expressed by the formula (1):

Are performed by the conditions stirring Froude number (Fr) is 200 or more 550 or less calculated from an average particle size of the external additive to be used in the first stage of the process is 6nm or more 20nm or less, production of the toner Method. An external additive according to the coverage of the toner particles after the first stage process is 10% or more and 60% or less, the production method of toner of claim 1 Symbol placement. The method for producing a toner according to claim 1 or 2 , wherein the coverage of the obtained toner with an external additive is 70% or more and 200% or less. The toner particles according to any one of claims 1 to 3 , wherein the toner particles are obtained by a method including a kneading step of melt-kneading the binder resin and the colorant and a crushing step of crushing the obtained kneaded product. Production method.