JP7443993B2 - Method for producing carbon black-containing toner for electrostatic image development - Google Patents

Description

The present disclosure relates to an electrostatic image developing toner (hereinafter sometimes simply referred to as "toner") used for developing an electrostatic latent image in electrophotography, electrostatic recording, electrostatic printing, and the like. ), and particularly relates to a method for producing a carbon black-containing toner for developing electrostatic images.

In image forming devices such as electrophotographic devices, electrostatic recording devices, and electrostatic printing devices, a desired image is created by developing an electrostatic latent image formed on a photoreceptor with toner for developing an electrostatic image. Image forming methods are widely practiced and applied to copying machines, printers, facsimile machines, and multifunctional devices equipped with these functions.

In recent years, there has been an increasing need for color image forming apparatuses using electrophotography, such as multifunction devices, facsimiles, and printers. In color printing, images such as photographs that require high resolution and clear color tone reproduction are also printed, and therefore there is a need for color toners that can provide image characteristics that can correspond to this. In addition, for such toners, there are various issues such as environmental stability from the perspective of preventing image quality deterioration due to changes in the environment such as temperature and humidity, printing durability from the perspective of reducing printing costs, and from the perspective of reducing power consumption. Various printing performances are required, such as low-temperature fixability.
In order to meet the above requirements, a spherical toner with a small particle size is suitable because it can achieve both good transferability and dot reproducibility, and a polymerization method has been proposed as a method for producing the toner. Conventional pulverization methods have low yields and consume a lot of energy for pulverization, especially when producing toner with small particle sizes, whereas polymerization methods have high yields and do not require a pulverization step. Energy consumption is low, and spherical toner can be easily produced.

Methods for producing toner by polymerization (hereinafter referred to as "polymerized toner") include suspension polymerization, emulsion polymerization, and dispersion polymerization. In the suspension polymerization method, first, a polymerizable monomer, a colorant, and other additives are mixed as necessary to form a polymerizable monomer composition, which is then added to an aqueous system containing a dispersion stabilizer. Disperse in a dispersion medium. Next, droplets of the polymerizable monomer composition are formed by applying a high shear to the aqueous dispersion medium in which the polymerizable monomer composition is dispersed using a high-speed stirrer or the like. Thereafter, the aqueous dispersion medium in which the droplet-formed polymerizable monomer composition is dispersed is polymerized in the presence of a polymerization initiator, and colored resin particles are obtained through filtration with a filter material, washing, and drying. Further, external additives such as inorganic fine particles are mixed with the colored resin particles to obtain a polymerized toner.
In this way, when obtaining colored resin particles by the polymerization method, the conventional pulverization method is It has the great advantage of being able to form spherical colored resin particles with a small particle size and a sharper particle size distribution.
However, in recent years, demands for high resolution and high image quality have become higher and higher.

When producing a toner containing carbon black as a colorant by a polymerization method, the polymerizable monomer composition is It is necessary to disperse carbon black finely and uniformly in the material. Unless carbon black is finely and uniformly dispersed at the stage of preparing the polymerizable monomer composition, a toner in which carbon black is finely and uniformly dispersed cannot be obtained.

As a general problem with toners, it is necessary to disperse the colorant finely and uniformly, but if carbon black cannot be finely and uniformly dispersed, since carbon black is a conductive material, charging characteristics may vary between individual toner particles. There is a problem in that variations occur and the entire toner cannot be triboelectrically charged uniformly. Further, depending on the content or type of carbon black, the image characteristics of the toner may not be able to reach the target level, such as the image density not being increased or fogging or hollow spots occurring easily.
The above-mentioned problem tends to be noticeable when a black toner is produced using carbon black, and is particularly noticeable when a toner is produced by increasing the amount of carbon black in order to obtain a clear black image.

However, since carbon black has poor dispersibility, it is difficult to efficiently obtain a polymerizable monomer composition in which carbon black is finely and uniformly dispersed.
Polymerizability that finely and uniformly disperses carbon black by performing dispersion treatment using a media-type dispersion machine and coexisting media particles that promote shearing motion in a mixture of polymerizable monomer and carbon black. A monomer composition can be obtained relatively efficiently.

Patent Document 1 discloses that a polymerizable monomer mixture containing a polymerizable monomer and a colorant is auxiliary dispersed using a high shear force stirring device that does not use media particles, and then a media type dispersion machine is used. A step of preparing a dispersion polymerizable monomer mixture by dispersing the dispersion polymerizable monomer mixture, and then granulating a dispersion polymerizable monomer composition containing the dispersion polymerizable monomer mixture in an aqueous dispersion medium. A method for producing a polymerized toner is described.

On the other hand, Patent Document 2 discloses a rotor in which a plurality of protrusions are arranged in an annular manner so that slits are formed between the protrusions in a colorant dispersion step, and the rings formed by the protrusions are formed in multiple stages on a concentric circle. A monomer composition containing at least a colorant and a polymerizable monomer is dispersed using a dispersing machine in which a stator having a similar shape and a stator are installed coaxially so as to maintain a constant interval and mesh with each other. A toner characterized in that the colorant is dispersed by passing in a centrifugal direction between the stator and the rotor, which rotates at a peripheral speed of 30 to 60 m/s at the outer circumference of the rotor. The manufacturing method is described.

JP2006-235206A Japanese Patent Application Publication No. 2006-201543

However, when dispersion treatment is performed for a long time by applying strong shear force using media particles in order to sufficiently disperse carbon black, fragments of media particles are mixed into the polymerizable monomer composition due to abrasion of the media particles. However, fragments of the media particles are incorporated into the toner, causing variations in chargeability between production lots. Therefore, it may not be possible to guarantee the target level of image characteristics such as image density, fogging, and voids.
Although the method of Patent Document 1 can shorten the time required for dispersion processing using a media-type disperser, the use of a media-type disperser cannot be completely avoided. In addition, in order to disperse the colorant in the polymerizable monomer mixture, it is necessary to use two devices: a stirring device that does not use media particles and a media-type dispersion machine, so the efficiency of the dispersion process is poor and the equipment The cost will also be high.
It cannot be said that the method of Patent Document 2 provides sufficient dispersibility of the colorant compared to a dispersion treatment using a media type dispersion machine. In Example 10 of Patent Document 2, after performing the above-described dispersion treatment on a monomer composition containing carbon black as a colorant, when further performing auxiliary dispersion using a media type dispersion machine, This shows that the image density and fog evaluation of toner containing carbon black are improved compared to the case where auxiliary dispersion using a media-type dispersion machine is not performed.

The problem of the present disclosure is to make carbon black polymerizable by a dispersion treatment without using media particles in a polymerization method including a step of preparing a polymerizable monomer composition containing carbon black as a polymerizable monomer and a colorant. An object of the present invention is to provide a method for producing a toner containing carbon black, which provides excellent image characteristics by dispersing the toner in a monomer.

According to the present disclosure, preparing a polymerizable monomer composition containing at least a polymerizable monomer, a colorant, and a charge control agent;
A step of granulating the polymerizable monomer composition in an aqueous dispersion medium to prepare a suspension in which droplets of the polymerizable monomer composition are dispersed;
A method for producing a toner, comprising a step of forming colored resin particles by subjecting the suspension to a polymerization reaction, the method comprising:
In the step of preparing the polymerizable monomer composition, the polymerizable monomer mixture containing at least a polymerizable monomer, carbon black as a colorant, and a charge control resin as a charge control agent is added with a comb-shaped Using a dispersing machine having a combination of a rotor and a stator, which are rings, arranged concentrically, dispersion processing is performed with the circumferential speed of the outer peripheral end of the rotor within a range of 15 m/s or more and 60 m/s or less. , a method for producing a carbon black-containing toner for developing electrostatic images is provided.

In one embodiment of the present disclosure, the content of the carbon black in the polymerizable monomer composition is 8 parts by mass or more and 15 parts by mass or less with respect to 100 parts by mass of the polymerizable monomer.

In one embodiment of the present disclosure, the charge control resin is a styrene acrylic polymer containing a quaternary ammonium base-containing (meth)acrylate monomer unit, and the quaternary ammonium base-containing (meth)acrylate in the styrene acrylic polymer is The copolymerization ratio of monomer units is 0.1% by mass or more and 3.0% by mass or less.

In one aspect of the present disclosure, in the step of preparing the polymerizable monomer composition, the polymerizable monomer mixture is introduced into the disperser and then discharged from the disperser, which is repeated and circulated. performs distributed processing.

In one embodiment of the present disclosure, the carbon black has an absorption amount of dibutyl phthalate of 40 mL/100 g or more and 100 mL/100 g or less.

In one embodiment of the present disclosure, the method for producing a carbon black-containing toner for developing an electrostatic image according to the present disclosure is a method for producing a black toner containing carbon black.

In one embodiment of the present disclosure, in the step of preparing the polymerizable monomer composition, dispersion is performed using only a dispersing machine having a combination of a rotor and a stator, both of which are comb-shaped rings, arranged concentrically. Perform processing.

In one embodiment of the present disclosure, in the step of preparing the suspension, the polymerizable monomer is dispersed using a disperser having a combination of a rotor and a stator, both of which are comb-shaped rings, arranged concentrically. The body composition is granulated in an aqueous dispersion medium.

According to the method for producing a carbon black-containing toner for developing electrostatic images of the present disclosure as described above, carbon black can be dispersed in a polymerizable monomer by a dispersion treatment that does not use media particles. It is possible to provide a carbon black-containing toner that provides image characteristics.

FIG. 1 is a perspective view schematically showing an example of a disperser used in the manufacturing method of the present disclosure. FIG. 2 is a cross-sectional view schematically showing an example of an apparatus including a disperser used in the manufacturing method of the present disclosure.

The method for producing a carbon black-containing toner for developing electrostatic images of the present disclosure includes the steps of preparing a polymerizable monomer composition containing at least a polymerizable monomer, a colorant, and a charge control agent;
A step of granulating the polymerizable monomer composition in an aqueous dispersion medium to prepare a suspension in which droplets of the polymerizable monomer composition are dispersed;
A method for producing a toner, comprising a step of forming colored resin particles by subjecting the suspension to a polymerization reaction, the method comprising:
In the step of preparing the polymerizable monomer composition, the polymerizable monomer mixture containing at least a polymerizable monomer, carbon black as a colorant, and a charge control resin as a charge control agent is added with a comb-shaped Using a dispersing machine that has a combination of a rotor and a stator, which are rings, arranged concentrically (in this disclosure, this may be referred to as a "comb tooth type coaxial ring dispersing machine"), the outer periphery of the rotor is It is characterized in that dispersion processing is performed with the circumferential speed of the end portion within a range of 15 m/s or more and 60 m/s or less.

In the production method of the present disclosure, in the step of preparing a polymerizable monomer composition, a polymerizable monomer mixture containing at least a polymerizable monomer, carbon black as a coloring agent, and a charge control resin as a charge control agent is added. After dispersing carbon black in a polymerizable monomer by performing a dispersion treatment using a comb-shaped coaxial ring type dispersing machine, by further adding additives such as a mold release agent as necessary. , preparing a polymerizable monomer composition.
Since the comb tooth type coaxial ring type disperser does not use media particles, when dispersing the polymerizable monomer mixture using the comb tooth type coaxial ring type disperser, avoid contamination with media particle fragments. be able to. However, compared to dispersion processing using a media-type dispersion machine, dispersion processing using a comb-tooth type coaxial ring dispersion machine is difficult to sufficiently disperse carbon black, especially when carbon black is used as a colorant. is difficult. Furthermore, if the circumferential speed of the rotor is increased too much in order to sufficiently disperse carbon black using a comb-shaped coaxial ring type dispersing machine, the pressure loss may increase, or the carbon black in the polymerizable monomer mixture may become too large. Separation may occur, resulting in the disadvantage that carbon black is not sufficiently dispersed.
To address this problem, in the present disclosure, carbon black is dispersed in a polymerizable monomer mixture in the presence of a charge control resin under specific conditions using a comb-shaped coaxial ring type disperser. Black can be sufficiently dispersed.
The reason why dispersibility is sufficiently improved by dispersing carbon black in the presence of a charge control resin has not been elucidated, but carbon black easily adsorbs to the charge control resin in the form of fine particles. The carbon black adsorbed on the polymerizable monomer has good affinity with the polymerizable monomer and is easily dispersed in the polymerizable monomer, so that the uniform dispersion of the carbon black is maintained, and the uniform dispersion of the charge control resin is also improved. It is thought that as a result of maintaining dispersion, the charging uniformity of the obtained toner is improved, and printing characteristics such as printing durability and image density are improved.

Hereinafter, a method for manufacturing a carbon black-containing toner for developing an electrostatic image of the present disclosure and a carbon black-containing toner for developing an electrostatic image obtained by the manufacturing method of the present disclosure will be described. The method for producing a carbon black-containing toner for developing an electrostatic image according to the present disclosure preferably further includes a step of attaching an external additive to the surface of the obtained colored resin particles after obtaining the colored resin particles.
In addition, in the present disclosure, "~" in a numerical range means that the numerical values described before and after it are included as a lower limit value and an upper limit value.
Furthermore, in the present disclosure, (meth)acrylate represents each of acrylate and methacrylate, and (meth)acrylic represents each of acrylic and methacrylic.

1. Method for Manufacturing Colored Resin Particles In the method for manufacturing a carbon black-containing toner for developing electrostatic images of the present disclosure, (1) a polymerizable monomer composition containing at least a polymerizable monomer, a colorant, and a charge control agent; (2) granulating the polymerizable monomer composition in an aqueous dispersion medium to prepare a suspension in which droplets of the polymerizable monomer composition are dispersed; 3) Colored resin particles are obtained by a method including a step of forming colored resin particles by subjecting the suspension to a polymerization reaction. In the manufacturing method of the present disclosure, the steps up to obtaining colored resin particles further include other steps different from the steps (1) to (3) above, to the extent that the effects of the manufacturing method of the present disclosure are not impaired. It may be

(1) Step of preparing a polymerizable monomer composition In the manufacturing method of the present disclosure, the step of preparing a polymerizable monomer composition includes at least a polymerizable monomer, carbon black as a colorant, and a charge control agent. A polymerizable monomer mixture containing a charge control resin is subjected to a dispersion treatment using a comb-shaped coaxial ring type dispersion machine, and then other additives are added as necessary to increase the polymerizability. This is a step of preparing a monomer composition.
Hereinafter, each component contained in the polymerizable monomer composition prepared by this step and the dispersion treatment performed in this step will be explained.

(Polymerizable monomer)
In the present disclosure, a polymerizable monomer refers to a monomer having a polymerizable functional group. The polymerizable monomer is polymerized by a polymerization reaction of the suspension, which will be described later, and becomes a binder resin in the toner.
The polymerizable monomer contained in the polymerizable monomer composition preferably contains a monovinyl monomer as a main component.
Examples of monovinyl monomers include styrene; styrene derivatives such as vinyltoluene and α-methylstyrene; acrylic acid and methacrylic acid; methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, and 2-acrylic acid. - Acrylic esters such as ethylhexyl and dimethylaminoethyl acrylate; methacrylic esters such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, and dimethylaminoethyl methacrylate; acrylonitrile , and nitrile compounds such as methacrylonitrile; amide compounds such as acrylamide and methacrylamide; and olefins such as ethylene, propylene, and butylene. These monovinyl monomers can be used alone or in combination of two or more. Among these, styrene, styrene derivatives, and acrylic esters or methacrylic esters are preferably used as monovinyl monomers.

The content of the monovinyl monomer contained in the polymerizable monomer composition is not particularly limited, but from the viewpoint of improving the dispersibility of carbon black, the monovinyl monomer in 100 parts by mass of the polymerizable monomer is The content is preferably 90 parts by mass or more, more preferably 95 parts by mass or more.

Moreover, the polymerizable monomer composition may further contain a crosslinkable polymerizable monomer (crosslinkable monomer) as a polymerizable monomer. A crosslinkable polymerizable monomer refers to a monomer having two or more polymerizable functional groups. By using any crosslinkable polymerizable monomer together with the monovinyl monomer, the hot offset resistance and storage stability of the toner can be improved.
Examples of crosslinkable polymerizable monomers include aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene, and derivatives thereof; alcohols having two or more hydroxyl groups such as ethylene glycol dimethacrylate and diethylene glycol dimethacrylate; Ester compounds in which two or more carboxylic acids having carbon-carbon double bonds are ester-bonded; other divinyl compounds such as N,N-divinylaniline and divinyl ether; compounds having three or more vinyl groups; etc. can be mentioned. These crosslinkable polymerizable monomers can be used alone or in combination of two or more.
When the polymerizable monomer composition contains a crosslinkable polymerizable monomer, the content of the crosslinkable polymerizable monomer is usually 0.1 to 5 parts by mass based on 100 parts by mass of the monovinyl monomer. Parts by weight, preferably 0.3 to 2 parts by weight.

The polymerizable monomer composition may further contain a macromonomer as a polymerizable monomer. When a macromonomer is used as part of the polymerizable monomer, the resulting toner has a good balance between storage stability and low-temperature fixability. The macromonomer has a polymerizable carbon-carbon unsaturated double bond at the end of its molecular chain, and is a reactive oligomer or polymer having a number average molecular weight of usually 1,000 to 30,000. The macromonomer is preferably one that provides a polymer having a higher Tg than the glass transition temperature (hereinafter sometimes referred to as "Tg") of a polymer obtained by polymerizing a monovinyl monomer.
When the polymerizable monomer composition contains a macromonomer, the content of the macromonomer is preferably 0.03 to 5 parts by mass, more preferably 0.05 to 1 part by mass, based on 100 parts by mass of monovinyl monomer. Part by mass.

(colorant)
The manufacturing method of the present disclosure is a method of manufacturing a toner containing carbon black as a colorant, and is typically a method of manufacturing a black toner.
As the carbon black, any known carbon black can be used, and there is no particular limitation, and for example, various carbon blacks such as furnace black, thermal lamp black, acetylene black, channel black, etc. can be used.
Although not particularly limited, carbon black having a primary particle size of 20 nm or more and 40 nm or less is preferably used.
In the present disclosure, these carbon blacks can be used alone or in combination of two or more.

The carbon black used in the present disclosure preferably has a dibutyl phthalate (DBP) absorption amount of 40 to 100 mL/100 g, more preferably 50 to 90 mL/100 g, and still more preferably 60 to 80 mL/100 g or more. When the DBP absorption amount of carbon black is at least the above lower limit, the dispersibility of carbon black is improved, and when it is at most the above upper limit, the coloring power of the toner is improved.
Note that the DBP absorption amount of carbon black is measured in accordance with "How to determine oil absorption amount" of ISO4656 (JIS K6217-4:2008).

In the polymerizable monomer composition, the content of carbon black is not particularly limited, but is preferably 8.0 parts by mass or more and 15.0 parts by mass or less with respect to 100 parts by mass of the polymerizable monomer. Preferably it is 9.0 parts by mass or more and 13.0 parts by mass or less, more preferably 10.0 parts by mass or more and 12.5 parts by mass or less. When the carbon black content is at least the above lower limit value, the coloring power of the toner can be improved and an image with high image density can be formed, and on the other hand, the carbon black content is at least the above upper limit value. As a result, it is possible to suppress the deterioration of the dispersibility of carbon black and the deterioration of the charging uniformity of the colored resin particles, and it is possible to form an image in which the occurrence of fog is suppressed.
In addition, in the present disclosure, when calculating the content of carbon black with respect to 100 parts by mass of the polymerizable monomer, the content of each polymerizable monomer contained in the polymerizable monomer composition and the calculated carbon The black content is a value rounded to the first decimal place according to Rule B of JIS Z8401:1999.
In order to obtain clear black images, it is necessary to increase the carbon black content to within the above range, but in conventional toner manufacturing methods, if the carbon black content is within the above range, the carbon black In some cases, the dispersion of the image becomes non-uniform, resulting in deterioration of image characteristics. On the other hand, according to the manufacturing method of the present disclosure, the dispersibility of carbon black can be improved, so even if the content of carbon black is within the above range, deterioration of image characteristics can be suppressed, and image characteristics can be suppressed. It is possible to obtain excellent clear black images.

In the present disclosure, the polymerizable monomer composition may further contain other colorants other than carbon black as a coloring agent, as long as the effects of the production method of the present disclosure are not impaired. Other colorants are not particularly limited, and known colorants used in toners can be used.
When the polymerizable monomer composition contains a colorant other than carbon black, the content of carbon black in 100 parts by mass of the colorant in the polymerizable monomer composition is preferably 80 parts by mass. The amount is more preferably 90 parts by mass or more, still more preferably 95 parts by mass or more. The colorant may consist only of carbon black.
In addition, when the polymerizable monomer composition contains a colorant other than carbon black, the content of the colorant different from carbon black is as follows: It is preferably 10 parts by mass or less, more preferably 5 parts by mass or less.

(Charge control agent)
The polymerizable monomer composition contains a charge control resin as a charge control agent. As the charge control resin, both positive charge control resin and negative charge control resin are preferably used.

Examples of the positive charge control resin include JP-A-63-60458, JP-A-3-175456, JP-A-3-243954, JP-A-11-15192, and International Publication No. 2017/170278. A quaternary ammonium (salt) group-containing copolymer produced according to the description can be preferably used, and among them, a quaternary ammonium base-containing (meth)acrylate described in International Publication No. 2017/170278 etc. Styrene acrylic polymers containing monomer units are preferred.
Furthermore, examples of the positive charge control resin that can be used in the manufacturing method of the present disclosure include known polyamine resins that are used as positive charge control resins.

The preferred styrene acrylic polymer containing a quaternary ammonium base-containing (meth)acrylate monomer unit contains at least a vinyl aromatic hydrocarbon monomer unit and a quaternary ammonium base-containing (meth)acrylate monomer unit. It may also contain a (meth)acrylate monomer unit that does not contain a quaternary ammonium base.
Examples of quaternary ammonium base-containing (meth)acrylate monomers include N,N,N-trimethyl-N-(2-methacryloxyethyl)ammonium chloride (DMC: dimethylaminoethylmethyl methacrylate), N- Examples include benzyl-N,N-dimethyl-N-(2-methacryloxyethyl)ammonium chloride (DML: dimethylaminoethylbenzyl methacrylate). These monomers can be used alone or in combination of two or more.
The styrene-acrylic polymer containing the quaternary ammonium base-containing (meth)acrylate monomer unit used in the present disclosure has a copolymerization ratio of the quaternary ammonium base-containing (meth)acrylate monomer unit of 0.1 to 3. Preferably, it is 0% by mass. The copolymerization ratio of the quaternary ammonium base-containing (meth)acrylate monomer unit is more preferably 0.3 to 2.5% by mass, and even more preferably 0.5 to 2.0% by mass.

A vinyl aromatic hydrocarbon monomer is a compound (monomer) having a structure in which a vinyl group is bonded to an aromatic hydrocarbon, such as styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene. , 4-methylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, 2-propylstyrene, 3-propylstyrene, 4-propylstyrene, 2-isopropylstyrene, 3-isopropylstyrene, 4-isopropylstyrene , 2-chlorostyrene, 3-chlorostyrene, 4-chlorostyrene, 2-methyl-α-methylstyrene, 3-methyl-α-methylstyrene, 4-methyl-α-methylstyrene, 2-ethyl-α-methyl Styrene, 3-ethyl-α-methylstyrene, 4-ethyl-α-methylstyrene, 2-propyl-α-methylstyrene, 3-propyl-α-methylstyrene, 4-propyl-α-methylstyrene, 2-isopropyl -α-methylstyrene, 3-isopropyl-α-methylstyrene, 4-isopropyl-α-methylstyrene, 2-chloro-α-methylstyrene, 3-chloro-α-methylstyrene, 4-chloro-α-methylstyrene , 2,3-dimethylstyrene, 3,4-dimethylstyrene, 2,4-dimethylstyrene, 2,6-dimethylstyrene, 2,3-diethylstyrene, 3,4-diethylstyrene, 2,4-diethylstyrene, 2,6-diethylstyrene, 2-methyl-3-ethylstyrene, 2-methyl-4-ethylstyrene, 2-chloro-4-methylstyrene, 2,3-dimethyl-α-methylstyrene, 3,4-dimethyl -α-methylstyrene, 2,4-dimethylstyrene, 2,6-dimethyl-α-methylstyrene, 2,3-diethyl-α-methylstyrene, 3,4-diethyl-α-methylstyrene, 2,4- Diethyl-α-methylstyrene, 2,6-diethyl-α-methylstyrene, 2-ethyl-3-methyl-α-methylstyrene, 2-methyl-4-propyl-α-methylstyrene, 2-chloro-4- Examples include ethyl-α-methylstyrene.
Examples of (meth)acrylate monomers without a quaternary ammonium base include methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, and n-amyl acrylate. , isoamyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, hydroxypropyl acrylate, lauryl acrylate, and other acrylic acid esters; methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, methacrylic acid Methacrylic acid esters such as n-butyl, isobutyl methacrylate, n-amyl methacrylate, isoamyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, hydroxypropyl methacrylate, and lauryl methacrylate; and the like.

A styrene acrylic polymer containing a quaternary ammonium base-containing (meth)acrylate monomer unit can be produced, for example, according to the description in International Publication No. 2017/170278. That is, (a) a vinyl aromatic hydrocarbon monomer, a vinyl monomer such as a (meth)acrylate monomer that does not contain a quaternary ammonium base, and a (meth)acrylate monomer containing a quaternary ammonium base; (b) a method obtained by reacting the copolymer obtained in (a) above with para-toluenesulfonic acid, methanesulfonic acid, etc.; and (c) a method obtained by copolymerizing the above vinyl monomer. and a dialkylaminoalkyl (meth)acrylate monomer to produce a copolymer obtained by quaternizing the nitrogen atom of the dialkylaminoalkyl group with a quaternizing agent. I can do it.

Examples of dialkylaminoalkyl (meth)acrylate monomers include dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, dipropylmethylaminoethyl (meth)acrylate, dibutylaminoethyl (meth)acrylate, and the like. It will be done.
Examples of the quaternizing agent include halogenated organic compounds such as methyl chloride, methyl bromide, ethyl chloride, ethyl bromide, benzyl chloride, and benzyl bromide; methyl sulfonic acid alkyl ester, ethyl sulfonic acid alkyl ester, propyl sulfonic acid alkyl ester , sulfonic acid alkyl esters such as benzenesulfonic acid alkyl ester and para-toluenesulfonic acid alkyl ester; and the like.

As the styrene acrylic polymer containing a quaternary ammonium base-containing (meth)acrylate monomer unit, a commercially available product may be used. As a commercially available product of the styrene acrylic polymer, for example, FCA-676P (trade name, manufactured by Fujikura Kasei Co., Ltd., Tg: 73 °C, weight average molecular weight (Mw): 19,500), FCA-592P (trade name, manufactured by Fujikura Kasei Co., Ltd., Tg: 82°C, weight average molecular weight (Mw): 12,000), FCA-700P (trade name, manufactured by Fujikura Kasei Co., Ltd.), etc. in which the copolymerization ratio of the quaternary ammonium base-containing acrylate monomer is 0.5% by mass), etc. can be mentioned.

In the present disclosure, when a positively chargeable charge control agent is used as the charge control agent, a positively chargeable charge control agent different from the charge control resin may be further contained. Examples of the positively chargeable charge control agent different from the charge control resin include nigrosine dye (azine compound), quaternary ammonium salt, triaminotriphenylmethane compound, imidazole compound, and the like. Commercially available products may be used as these positively chargeable charge control agents. Examples of commercially available nigrosine dyes include the BONTRON (registered trademark) N series manufactured by Orient Chemical Industry Co., Ltd., the NIGROSINE BASE series manufactured by Orient Chemical Industry Co., Ltd., and the NUBIAN (registered trademark) BLACK series. can. Commercially available quaternary ammonium salts include, for example, BONTRON (registered trademark) P series manufactured by Orient Kagaku Kogyo Co., Ltd., COPY CHARGE NX VP434 and COPY CHARGE NEG VP2036 manufactured by Clariant. Examples of commercially available triaminotriphenylmethane compounds include COPY BLUE PR manufactured by Clariant.

In the present disclosure, when a positively chargeable charge control agent is used as the charge control agent, the content of the positive charge control resin in 100 parts by mass of the charge control agent contained in the polymerizable monomer composition is particularly preferably as described above. The content of the styrene acrylic polymer containing the quaternary ammonium base-containing (meth)acrylate monomer unit is preferably 80 parts by mass or more, more preferably 90 parts by mass or more, and 95 parts by mass or more. More preferably, the positively chargeable charge control agent may consist only of the above-mentioned preferred styrene-acrylic polymer.

Further, in the present disclosure, when a positively chargeable charge control agent is used as the charge control agent, the content of the charge control agent in the polymerizable monomer composition is as follows with respect to 100 parts by mass of the polymerizable monomer: The amount is preferably 0.1 to 15.0 parts by weight, more preferably 1.0 to 14.0 parts by weight, and even more preferably 2.0 to 13.0 parts by weight.
In addition, in the present disclosure, when a positively chargeable charge control agent is used as the charge control agent, the styrene acrylic polymer containing the quaternary ammonium base-containing (meth)acrylate monomer unit in the polymerizable monomer composition is The content is preferably 0.1 to 15.0 parts by weight, more preferably 1.0 to 14.0 parts by weight, and 2.0 parts by weight based on 100 parts by weight of the polymerizable monomer. More preferably, the amount is 13.0 parts by mass.

In the present disclosure, when a styrene acrylic polymer containing a quaternary ammonium base-containing (meth)acrylate monomer unit is used as the charge control agent, the content of the styrene acrylic polymer based on 100 parts by mass of the polymerizable monomer (parts by mass) and the copolymerization ratio (% by mass) of the quaternary ammonium base-containing (meth)acrylate monomer unit in the styrene-acrylic polymer is preferably 1.5 to 7.5, More preferably 4.0 to 7.0, still more preferably 5.0 to 6.5.

Examples of the negative charge control resin include sulfonic acid (salt) group-containing copolymers produced according to the descriptions in JP-A-1-217464, JP-A-3-15858, and International Publication No. 2015/80272. Coalescence can be preferably used, and in particular, vinyl aromatic hydrocarbon monomer units and (meth)acrylate monomer units described in International Publication No. 2015/80272, etc., and sulfonic acid group-containing (meth) A sulfonic acid group-containing polymer containing an acrylamide monomer unit is preferred. In addition, in the sulfonic acid group-containing polymer, the sulfonic acid group also includes its salt (sulfonic acid group).

Examples of the sulfonic acid group-containing (meth)acrylamide monomer used in the preferred sulfonic acid group-containing polymer include 2-acrylamide-2-methylpropanesulfonic acid, 2-acrylamide-n-butanesulfonic acid, and 2-acrylamide. -2-phenylpropanesulfonic acid, 2-acrylamido-2,2,4-trimethylpentanesulfonic acid and the like. These monomers can be used alone or in combination of two or more.
The sulfonic acid group-containing polymer containing a vinyl aromatic hydrocarbon monomer unit, a (meth)acrylate monomer unit, and a sulfonic acid group-containing (meth)acrylamide monomer unit used in the present disclosure has a sulfonic acid group. The copolymerization ratio of the (meth)acrylamide monomer unit contained is preferably 0.8 to 4.0% by mass, more preferably 1.0 to 3.5% by mass, and 1.5 to 3% by mass. More preferably, it is .0% by mass. When the copolymerization ratio of the sulfonic acid group-containing (meth)acrylamide monomer unit is at least the above lower limit, a sufficient effect of imparting negative chargeability can be obtained, and when it is at most the above upper limit, dispersion stability can be improved. The uniformity of the particle size of the colored resin particles can be improved. Further, by setting the copolymerization ratio of the sulfonic acid group-containing (meth)acrylamide monomer unit within the above range, deterioration of the environmental stability of image quality can be suppressed.

Examples of the vinyl aromatic hydrocarbon monomer used in the preferred sulfonic acid group-containing polymer include those similar to the vinyl aromatic hydrocarbon monomers used in the styrene-acrylic polymer described above.
Examples of the (meth)acrylate monomer used in the above-mentioned preferable sulfonic acid group-containing polymer include those similar to the (meth)acrylate monomers without a quaternary ammonium base used in the above-mentioned styrene-acrylic polymer. I can do it.
In the sulfonic acid group-containing polymer containing a vinyl aromatic hydrocarbon monomer unit, a (meth)acrylate monomer unit, and a sulfonic acid group-containing (meth)acrylamide monomer unit used in the present disclosure, the vinyl aromatic The copolymerization ratio (based on mass) of the hydrocarbon monomer and (meth)acrylate monomer is not particularly limited, but from the viewpoint of heat-resistant storage stability, low-temperature fixability, and dispersibility, it is usually 99:1 to 1. The ratio is 50:50, preferably 95:5 to 70:30.
The preferred sulfonic acid group-containing polymer can be produced, for example, according to the description in International Publication No. 2015/80272.

In the present disclosure, when a negatively chargeable charge control agent is used as the charge control agent, a negatively chargeable charge control agent different from the charge control resin may be further contained. Examples of the negatively chargeable charge control agent different from the charge control resin include azo dyes containing metals such as Cr, Co, Al, and Fe, metal salicylate compounds, and metal alkyl salicylate compounds. Commercially available products may be used as these negatively chargeable charge control agents. Commercially available azo dyes include, for example, BONTRON (registered trademark) S series manufactured by Orient Chemical Industry Co., Ltd., Eizenspiron Black TRH manufactured by Hodogaya Chemical Industry Co., Ltd., and salicylic acid metal compounds. Alternatively, commercially available metal alkyl salicylate compounds include, for example, the product name BONTRON (registered trademark) E series manufactured by Orient Chemical Industry Co., Ltd.

In the present disclosure, when a negatively chargeable charge control agent is used as the charge control agent, the content of the negative charge control resin in 100 parts by mass of the charge control agent contained in the polymerizable monomer composition is particularly preferably as described above. The content of a sulfonic acid group-containing polymer containing a vinyl aromatic hydrocarbon monomer unit, a (meth)acrylate monomer unit, and a sulfonic acid group-containing (meth)acrylamide monomer unit is 80 parts by mass or more. The amount is preferably 90 parts by mass or more, even more preferably 95 parts by mass or more, and the negatively chargeable charge control agent consists only of the above-mentioned preferred sulfonic acid group-containing polymer. Good too.

Further, in the present disclosure, when a negatively chargeable charge control agent is used as the charge control agent, the content of the charge control agent in the polymerizable monomer composition is as follows with respect to 100 parts by mass of the polymerizable monomer: The amount is preferably 0.1 to 8.0 parts by weight, more preferably 0.2 to 7.0 parts by weight, and even more preferably 0.3 to 6.5 parts by weight.
Further, in the present disclosure, when a negatively chargeable charge control agent is used as the charge control agent, a vinyl aromatic hydrocarbon monomer unit and a (meth)acrylate monomer unit in the polymerizable monomer composition, The content of the sulfonic acid group-containing polymer containing the sulfonic acid group-containing (meth)acrylamide monomer unit is preferably 0.1 to 8.0 parts by weight based on 100 parts by weight of the polymerizable monomer. The amount is preferably 0.2 to 7.0 parts by weight, more preferably 0.3 to 6.5 parts by weight.

In the present disclosure, a sulfonic acid group-containing polymer containing a vinyl aromatic hydrocarbon monomer unit, a (meth)acrylate monomer unit, and a sulfonic acid group-containing (meth)acrylamide monomer unit is used as the charge control agent. When used, the content (parts by mass) of the sulfonic acid group-containing polymer relative to 100 parts by mass of the polymerizable monomer, and the copolymerization of the sulfonic acid group-containing (meth)acrylamide monomer unit in the sulfonic acid group-containing polymer. The product with the ratio (mass%) is preferably 0.4 to 32.0, more preferably 0.7 to 24.5, and even more preferably 0.9 to 19.5.

The charge control resin used in the manufacturing method of the present disclosure preferably has a weight average molecular weight (Mw) of 2,000 to 50,000, more preferably 4,000 to 40,000, and more preferably 6,000 to 50,000. 35,000 is most preferred. If the weight average molecular weight of the charge control resin is less than 2,000, offset may occur, and if it exceeds 50,000, fixing performance may deteriorate. In the present disclosure, the weight average molecular weight (Mw) of a polymer can be determined in terms of polystyrene by GPC using a sample dissolved in tetrahydrofuran (THF).
Further, the glass transition temperature of the charge control resin used in the manufacturing method of the present disclosure is preferably 40 to 80°C, more preferably 45 to 75°C, and still more preferably 45 to 70°C. If the glass transition temperature is less than 40°C, the storage stability of the toner may deteriorate, and if it exceeds 80°C, the fixability may deteriorate.

The polymerizable monomer composition preferably contains a release agent from the viewpoint of improving the releasability of the toner from the fixing roll during fixing. The mold release agent is not particularly limited as long as it is generally used as a mold release agent for toners, and examples thereof include polyolefin waxes such as low molecular weight polyethylene, low molecular weight polypropylene, and low molecular weight polybutylene; candelilla, carnauba, etc. Natural waxes such as , rice, wood wax, and jojoba; Petroleum waxes such as paraffin, microcrystalline, and petrolatum; Mineral waxes such as montan, ceresin, and ozokerite; Synthetic waxes such as Fischer-Tropsch wax; Pentaerythritol tetramyristate, Pentaerythritol esters such as pentaerythritol tetrapalmitate, pentaerythritol tetrastearate, and pentaerythritol tetralaurate; and dipentaerythritol hexamyristate, dipentaerythritol hexapalmitate, and dipentaerythritol hexalaurate. Examples include polyhydric alcohol ester compounds such as pentaerythritol ester. These mold release agents may be used alone or in combination of two or more.
The content of the mold release agent is preferably 0.1 to 30 parts by weight, more preferably 1 to 20 parts by weight, based on 100 parts by weight of the polymerizable monomer.

The polymerizable monomer composition preferably contains a molecular weight regulator. The molecular weight regulator is not particularly limited as long as it is generally used as a molecular weight regulator for toners, and examples thereof include t-dodecylmercaptan, n-dodecylmercaptan, n-octylmercaptan, and 2,2, Mercaptans such as 4,6,6-pentamethylheptane-4-thiol; tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, N,N'-dimethyl-N,N'-diphenylthiuram disulfide, N, Thiuram disulfides such as N'-dioctadecyl-N,N'-diisopropylthiuram disulfide; and the like. These molecular weight regulators may be used alone or in combination of two or more.
When the polymerizable monomer composition contains a molecular weight regulator, the content of the molecular weight regulator is usually 0.01 to 10 parts by mass, preferably 0.01 to 10 parts by mass, based on 100 parts by mass of the polymerizable monomer. It is 1 to 5 parts by mass.

(Distributed processing)
The manufacturing method of the present disclosure includes, in the step of preparing a polymerizable monomer composition, a polymerizable monomer mixture containing at least a polymerizable monomer, carbon black as a colorant, and a charge control resin as a charge control agent. Dispersion processing is performed using a dispersing machine (comb-tooth coaxial ring type dispersion machine) having a combination of a rotor and a stator, both of which are comb-tooth rings, arranged concentrically.
In addition, in the process of preparing the polymerizable monomer composition, mixing and stirring performed separately from the dispersion treatment, such as preliminary dispersion treatment performed before the dispersion treatment and auxiliary dispersion treatment performed after the dispersion treatment, etc. Alternatively, it may include a step of performing a dispersion process.

Hereinafter, in the description of the dispersion machine used in this step, the mixed liquid that undergoes the dispersion treatment will be referred to as a "dispersion liquid."
FIG. 1 is a perspective view schematically showing an example of a disperser used in the manufacturing method of the present disclosure. FIG. 1 shows a state in which parts including a rotor 4, a stator 5, and a drive shaft 6 are separated to make it easier to understand the characteristics of the disperser used in this process. The disperser shown in FIG. 1 has a combination of a rotor 4 and a stator 5, both of which are comb-shaped rings, arranged concentrically, and the rotor 4 is rotated at high speed by driving a drive shaft 6. , the dispersion liquid is passed from the inside of the rotor 4 to the outside of the stator 5, and the dispersion liquid is stirred in the gap between the rotor 4 and the stator 5. In the disperser shown in FIG. 1, a combination of a rotor 4 and a stator 5 is arranged in one step along the axial direction of a drive shaft 6, and is concentrically arranged outward from the center of the drive shaft 6. It is arranged in three stages at the top.
FIG. 2 is a cross-sectional view schematically showing an example of an apparatus including a disperser used in the manufacturing method of the present disclosure. The apparatus shown in FIG. 2 includes a tank 1 for storing a dispersion liquid and a disperser 2. The disperser 2 shown in FIG. 2 has a combination of a rotor 4 and a stator 5, both of which are comb-shaped rings, arranged concentrically in a casing, and the rotor 4 is driven by a drive shaft 6. The dispersion liquid is circulated from the inside of the rotor 4 to the outside of the stator 5 by rotating at high speed, and the dispersion liquid is stirred in the gap between the rotor 4 and the stator 5. In the disperser 2 shown in FIG. 2, a combination of a rotor 4 and a stator 5 is arranged in three stages along the axial direction of the drive shaft 6, and the combinations are arranged in three stages from the center side of the drive shaft 6 toward the outside. They are arranged concentrically in two or three stages.
The rotor and stator included in the disperser used in the manufacturing method of the present disclosure include, for example, a plurality of annularly arranged protrusions and slits formed between the protrusions. The width of the slit portion is not particularly limited, but may be, for example, within a range of 0.05 to 6 mm. By setting the width of the slit portion within the above range, pressure loss can be suppressed and stirring can be performed with sufficient energy.
Note that the combination of a rotor and a stator refers to a combination of a rotor and a stator that are arranged to mesh with each other at regular intervals. In addition, the combination of the rotor and stator is arranged concentrically in multiple stages from the center side of the drive shaft toward the outside, which means that the rotor and stator have multiple protrusions and slits between the protrusions. This means that the rings formed by the parts are arranged concentrically in multiple stages. In each combination of rotor and stator arranged in multiple stages along the axial direction of the drive shaft, the rings of the rotor and stator are concentrically arranged in multiple stages from the center side of the drive shaft to the outside. It may be arranged in
If the combination of rotor and stator is arranged concentrically in multiple stages from the center of the drive shaft to the outside, the width of the slit becomes narrower from the center of the drive shaft to the outside. It is preferable that the rotor and stator are arranged in such a manner that the rotor and the stator are arranged in this order.
In the dispersion machine used in the manufacturing method of the present disclosure, the combination of the rotor and the stator is arranged in two or more stages in the direction of movement of the dispersion, as shown in FIGS. 1 and 2. or may be arranged in one step. From the viewpoint of narrowing the particle size distribution of the colored resin particles obtained, it is preferable that combinations of rotors and stators are arranged in multiple stages in the direction of travel of the dispersion. Above all, it is preferable that the combination of the rotor and the stator is arranged concentrically in two or three stages outward from the center of the drive shaft.
In the above-mentioned dispersing machine, the number of teeth of the rotor and stator is appropriately selected depending on the particle size of the toner to be manufactured, and although there is no particular limitation, the combination of the rotor and stator is If the rotor and stator are arranged at multiple stages along It is preferable. For example, the combination of the rotor and stator in the dispersion machine is arranged in three stages from the inlet side to the outlet side of the dispersion liquid, in the order of coarse teeth, medium teeth, and fine teeth. , 3 stages in the order of medium teeth, 3 stages in the order of coarse teeth, fine teeth, fine teeth, 2 stages in the order of coarse teeth, middle teeth, and 2 stages in the order of coarse teeth, fine teeth. It is preferable that

In the production method of the present disclosure, when dispersing the polymerizable monomer mixture, the peripheral speed of the outer peripheral end of the rotor of the dispersing machine is set to 15 to 60 m/s, preferably 20 to 50 m/s, More preferably, the speed is 25 to 40 m/s. Note that in the present disclosure, the circumferential speed of the outer peripheral end of the rotor may be simply referred to as "the circumferential speed of the rotor." By setting the circumferential speed of the rotor of the above-mentioned dispersing machine to the above-mentioned lower limit value or more, the dispersion process is performed with sufficient energy to easily disperse carbon black, and the carbon black is uniformly distributed before carbon black agglomeration occurs. can be dispersed into On the other hand, since the circumferential speed of the rotor of the dispersion machine is below the above upper limit, pressure loss due to the circumferential speed of the rotor being too high and separation of carbon black in the polymerizable monomer mixture are suppressed. Therefore, carbon black can be easily dispersed uniformly. Furthermore, by setting the circumferential speed of the rotor of the dispersion machine to be equal to or less than the upper limit value, it is possible to partially inhibit the polymerization reaction from proceeding due to a rise in temperature, and thus it is also possible to prevent deterioration of the fixability of the toner.

In addition, in the step of preparing the polymerizable monomer composition, the dispersion treatment may be performed by repeatedly circulating the polymerizable monomer mixture by introducing it into the dispersion machine and then discharging it from the dispersion machine. is preferred. For example, by using a device as shown in Figure 2, in which the above-mentioned disperser is connected to a tank for storing a dispersion liquid, the polymerizable monomer mixture is introduced from the tank into the disperser, stirred in the disperser, and then , and can be repeatedly circulated by discharging it into a tank. In the apparatus shown in Fig. 2, the dispersion liquid injected into tank 1 is supplied from tank 1 to disperser 2, stirred by disperser 2, and then discharged to tank 1, which is repeated to circulate within the apparatus. do. In the apparatus shown in FIG. 2, the dispersion liquid in the tank 1 is supplied to the dispersion machine 2 through the dispersion liquid inflow path 7 through an inner nozzle (not shown). The disperser 2 has three combinations of rotors 4 and stators 5 arranged in three stages along the axial direction of the drive shaft 6 in the casing. A cooling jacket 3 is provided on the inner wall of the casing. In the dispersion machine 2, the rotor 4 is rotated at high speed by driving the drive shaft 6, and the dispersion liquid is distributed from the inside of the rotor 4 to the outside of the stator 5, and the dispersion liquid is distributed in the gap between the rotor 4 and the stator 5. The dispersion is stirred and passed through the gap between the outermost comb teeth of the rotor 4 and the outermost comb teeth of the stator 5, and is made to flow downstream. The dispersion liquid stirred by the disperser 2 is returned to the tank 1 via the dispersion liquid circulation path 8. The dispersion liquid that has been circulated within the apparatus until reaching a desired number of circulations is discharged through the dispersion liquid discharge path 9 and used for the next step.
The method for feeding the dispersion liquid is not particularly limited, and examples thereof include a method using a liquid feeding pump. Moreover, the internal pressure of the disperser can be adjusted by adjusting the flow rate of the dispersion liquid discharged from the disperser. The internal pressure of the disperser is preferably 0.01 to 15 MPa, more preferably 0.05 to 10 MPa, and still more preferably 0.1 to 5 MPa. By setting the internal pressure of the disperser within the above range, carbon black can be efficiently dispersed while suppressing the generation of bubbles due to cavitation.

Note that the disperser shown in FIGS. 1 and 2 is a horizontal type in which the drive shaft extends in the horizontal direction, but the disperser used in the manufacturing method of the present disclosure is not limited to this, and the drive shaft extends in the direction of gravity. It may be a vertical type that extends along the .
In the manufacturing method of the present disclosure, a commercially available comb-shaped coaxial ring type disperser can be used. Commercially available devices equipped with a comb-shaped coaxial ring type disperser include horizontal multi-purpose machines such as Milder (trade name) manufactured by Pacific Kiko Co., Ltd. and Cavitron (trade name) manufactured by Eurotech Co., Ltd. Examples include a staged inline dispersion machine, a vertical multistage inline dispersion machine such as an inline dispersion machine manufactured by IKA (for example, DISPAX-REACTOR (registered trademark) DRS (trade name), etc.), and the like. Since all of these commercially available devices have a tank for storing the dispersion liquid, the polymerizable monomer mixture can be circulated to perform the dispersion treatment.

In the manufacturing method of the present disclosure, in the step of preparing a polymerizable monomer composition, the polymerizable monomer mixture is introduced into the above-mentioned dispersion machine and then discharged from the above-mentioned dispersion machine. It is preferable to carry out the dispersion treatment with the number of circulation calculated by formula (I) being preferably 8 to 30 times, more preferably 8 to 26 times, even more preferably 9 to 20 times.
Formula (I)
Number of circulation = {flow rate of dispersion liquid (liters/min) x processing time (minutes)}/amount of dispersion liquid (liters)
Here, the number of circulations means the number of times the dispersion liquid circulates within the dispersion machine. That is, by multiplying the flow rate (liters/min) of the dispersion liquid in the dispersion machine by the processing time (minutes) by the dispersion machine, the total throughput processed by the dispersion machine can be obtained. The number of circulations of the dispersion liquid can be calculated by dividing this total throughput by the dispersion liquid preparation amount (liters).
By setting the number of circulations within the above range, it is possible to improve the dispersibility of carbon black, improve the charging uniformity of the toner, increase the density of the image, and suppress fogging.

In the production method of the present disclosure, in the step of preparing a polymerizable monomer composition, the product of the circumferential speed (m/s) of the rotor of the disperser and the number of circulations calculated by the above formula (I) is further provided. Performing the dispersion treatment at (rotor circumferential speed (m/s) x number of circulations) preferably 300 to 600, more preferably 320 to 570, still more preferably 330 to 550, even more preferably 340 to 550. is preferred.
By setting the product of the circumferential speed (m/s) of the rotor of the dispersion machine and the circulation number calculated by the above formula (I) within the above range, the dispersibility of carbon black is improved and the toner is charged uniformly. It is possible to improve image quality, increase image density, and suppress fogging.
Further, in the manufacturing method of the present disclosure, the peripheral speed of the rotor of the disperser is 25 to 40 m/s, and the product of the peripheral speed (m/s) of the rotor of the disperser and the number of circulations is 340 m/s. ˜550 is particularly preferable.

In the manufacturing method of the present disclosure, the dispersion treatment using a comb-shaped coaxial ring type dispersion machine performed in the step of preparing the polymerizable monomer composition is a dispersion treatment performed using only the dispersion machine. , is preferable because it improves the dispersibility of carbon black, improves the charging uniformity of the toner, increases the density of images, and suppresses fogging.
In addition, in the manufacturing method of the present disclosure, if mixing, stirring, or dispersion treatment such as preliminary dispersion treatment or auxiliary dispersion treatment is performed separately from the dispersion treatment using a comb-tooth coaxial ring type dispersion machine, the mixing, stirring Alternatively, the dispersion treatment may be carried out without using a comb-shaped coaxial ring type disperser, but it is preferably carried out using a comb-shaped coaxial ring type disperser. Moreover, in this step, it is preferable not to use a media type disperser. In this process, if dispersion treatment or stirring treatment is performed using media particles, media fragments may be mixed into the toner particles due to abrasion of the media particles, resulting in a significant decrease in charging characteristics. This may cause variations in charging characteristics, resulting in insufficient image density or fogging.

The polymerizable monomer mixture to be subjected to the above dispersion treatment contains at least a polymerizable monomer, carbon black, and a charge control resin among the components contained in the polymerizable monomer composition obtained by this step. good.
Since the above dispersion process is a process for dispersing carbon black in the polymerizable monomer, the entire amount of carbon black to be contained in the toner is contained in the polymerizable monomer mixture to which the above dispersion process is performed. It is preferable that the This improves the dispersion stability of carbon black in the toner and improves the charging uniformity of the toner, thereby improving image characteristics.
In addition, in the polymerizable monomer mixture to be subjected to the above-mentioned dispersion treatment, the content of components different from the polymerizable monomer, carbon black, and charge control resin is determined from the viewpoint of suppressing a decrease in the dispersibility of carbon black. It is preferably 1 part by mass or less, more preferably 0.1 part by mass or less, per 100 parts by mass of the polymerizable monomer.

(2) Step of preparing a suspension In the step of preparing a suspension, the polymerizable monomer composition obtained in the above-mentioned step is granulated in an aqueous dispersion medium, and the polymerizable monomer composition is This is a process of preparing a suspension in which droplets of a substance are dispersed.

The aqueous dispersion medium used in this step contains at least an aqueous medium. In the present disclosure, an aqueous medium refers to a medium containing water as a main component.
The aqueous dispersion medium preferably contains a dispersion stabilizer. Examples of dispersion stabilizers include sulfates such as barium sulfate and calcium sulfate; carbonates such as barium carbonate, calcium carbonate, and magnesium carbonate; phosphates such as calcium phosphate; metals such as aluminum oxide and titanium oxide. Oxides; metal hydroxides such as aluminum hydroxide, magnesium hydroxide, and ferric hydroxide; inorganic compounds such as; water-soluble polymers such as polyvinyl alcohol, methyl cellulose, and gelatin; anionic surfactants; Examples include organic compounds such as nonionic surfactants; amphoteric surfactants; These dispersion stabilizers can be used alone or in combination of two or more.
Among the above-mentioned dispersion stabilizers, inorganic compounds, particularly colloids of sparingly water-soluble metal hydroxides, are preferred. By using an inorganic compound, especially a colloid of a poorly water-soluble metal hydroxide, the particle size distribution of the colored resin particles can be narrowed, and the amount of dispersion stabilizer remaining after washing can be reduced, resulting in an advantageous result. The resulting toner can reproduce images clearly and has excellent environmental stability.

In this step, when the polymerizable monomer composition is granulated in an aqueous dispersion medium, a polymerization initiator is added to the mixture of the polymerizable monomer composition and an aqueous dispersion medium to Preferably, droplet formation of the monomer composition is carried out. The polymerization initiator may be added after the polymerizable monomer composition is dispersed in the aqueous dispersion medium and before droplet formation; It may also be added to the polymer composition.
Examples of polymerization initiators include persulfates such as potassium persulfate and ammonium persulfate: 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis(2-methyl-N-(2- hydroxyethyl)propionamide), 2,2'-azobis(2-amidinopropane) dihydrochloride, 2,2'-azobis(2,4-dimethylvaleronitrile), and 2,2'-azobisisobutyronitrile Azo compounds such as di-t-butyl peroxide, benzoyl peroxide, t-butylperoxy-2-ethylhexanoate, t-butylperoxydiethyl acetate, t-hexylperoxy-2-ethylbutanoate , diisopropylperoxydicarbonate, di-t-butylperoxyisophthalate, and t-butylperoxyisobutyrate. These polymerization initiators can be used alone or in combination of two or more.
Among these polymerization initiators, organic peroxides are preferred because they can reduce residual polymerizable monomers and improve the printing durability of toner. Among organic peroxides, peroxy esters are preferable because they have good initiator efficiency and can reduce residual polymerizable monomers, and non-aromatic peroxy esters, that is, peroxy esters that do not have an aromatic ring, are more preferable. .

In this process, the above polymerizable monomer composition is granulated in an aqueous dispersion medium using a comb-shaped coaxial ring type dispersion machine, which improves the dispersibility of carbon black and improves the uniformity of toner charging. This is preferable from the viewpoint of improving image density, increasing image density, and suppressing fog. That is, in this step, the dispersion treatment for forming droplets of the polymerizable monomer composition in an aqueous dispersion medium is preferably performed using the above-mentioned dispersion machine, and it is not possible to perform the dispersion treatment using only the above-mentioned dispersion machine. More preferred.
As the comb-tooth coaxial ring type dispersion machine used in this step, the same one as the comb-tooth coaxial ring dispersion machine used for the dispersion treatment in the step of preparing the polymerizable monomer composition can be used. .
In addition, in this step, a preferred form of the comb-shaped coaxial ring type dispersion machine used for granulating the above-mentioned polymerizable monomer composition in an aqueous dispersion medium is such that the above-mentioned polymerizable monomer composition is This is the same as the preferred form in the preparation process.
In addition, preferable conditions such as the circumferential speed of the rotor, the number of circulations, and the product of the circumferential speed of the rotor (m/s) and the number of circulations in granulation using a comb-tooth type coaxial ring disperser are also as described above. The preferred conditions are the same as those in the process of preparing the polymerizable monomer composition.

In addition, in the suspension preparation process, mixing, stirring, or dispersion treatment performed for purposes other than granulation of the polymerizable monomer composition may be performed using a comb-shaped coaxial ring type dispersion machine. Alternatively, it may be carried out without using a comb-shaped coaxial ring type disperser. In this step, it is preferable not to use a media type disperser. In this step, if granulation, mixing, stirring, or dispersion treatment is performed using media particles, problems similar to those that may occur in the step of preparing the polymerizable monomer composition described above may occur.

(3) Step of forming colored resin particles This step is a step of forming colored resin particles by subjecting the suspension obtained in the above-mentioned step to a polymerization reaction. For example, the suspension can be subjected to a polymerization reaction by heating the suspension to the polymerization temperature of the polymerizable monomer.
The polymerization temperature in the above polymerization reaction is preferably 50°C or higher, more preferably 60 to 95°C. Further, the reaction time for polymerization is preferably 1 to 20 hours, more preferably 2 to 15 hours.

In the manufacturing method of the present disclosure, a toner may be prepared by directly adding an external additive to the colored resin particles obtained by subjecting the suspension to a polymerization reaction, but by subjecting the suspension to a polymerization reaction, It is preferable to use the resulting colored resin particles as a core layer, and to obtain so-called core-shell type (or also referred to as "capsule type") colored resin particles by forming a shell layer different from the core layer on the outer side of the core layer. Core-shell type colored resin particles have a core layer made of a substance with a low softening point coated with a substance with a higher softening point to achieve a balance between lowering the fixing temperature and preventing aggregation during storage. be able to.

There are no particular limitations on the method for producing core-shell type colored resin particles using colored resin particles obtained by subjecting the suspension to a polymerization reaction, and conventionally known methods can be used to produce them. An in situ polymerization method or a phase separation method is preferred from the viewpoint of production efficiency.

A method for producing core-shell colored resin particles using an in situ polymerization method will be described below.
A polymerizable monomer for forming a shell layer (hereinafter sometimes referred to as a polymerizable monomer for shell) and a polymerization initiator are added to an aqueous dispersion medium in which colored resin particles are dispersed. By polymerizing, core-shell type colored resin particles can be obtained.

As the polymerizable monomer for the shell, the same polymerizable monomers as mentioned above can be used. Among these, it is preferable to use monomers such as styrene, acrylonitrile, and methyl methacrylate, which can yield a polymer having a Tg of over 80° C., either alone or in combination of two or more.

Polymerization initiators used in the polymerization of the polymerizable monomer for the shell include persulfate metal salts such as potassium persulfate and ammonium persulfate; 2,2'-azobis(2-methyl-N-(2-hydroxyethyl)); water-soluble polymerization initiators such as 2,2′-azobis-(2-methyl-N-(1,1-bis(hydroxymethyl)2-hydroxyethyl)propionamide); Agents can be mentioned. These can be used alone or in combination of two or more. The amount of the polymerization initiator is preferably 0.1 to 30 parts by weight, more preferably 1 to 20 parts by weight, based on 100 parts by weight of the polymerizable monomer for shell.

The polymerization temperature of the shell layer is preferably 50°C or higher, more preferably 60 to 95°C. Further, the reaction time for polymerization of the shell layer is preferably 1 to 20 hours, more preferably 2 to 15 hours.

(4) Washing, filtration, dehydration, and drying process In the manufacturing method of the present disclosure, the aqueous dispersion of colored resin particles is washed, filtered, dehydrated, and dried to remove the dispersion stabilizer according to a conventional method. It is preferable to have a step of obtaining dried colored resin particles by carrying out the step. These washing, filtration, dehydration, and drying operations are preferably repeated several times as necessary.

As for the above-mentioned cleaning method, when an inorganic compound is used as a dispersion stabilizer, it is preferable to dissolve the dispersion stabilizer in water and remove it by adding acid or alkali to the aqueous dispersion of colored resin particles. . When a poorly water-soluble inorganic hydroxide colloid is used as a dispersion stabilizer, it is preferable to add an acid to adjust the pH of the colored resin particle aqueous dispersion to 6.5 or less. As the acid to be added, inorganic acids such as sulfuric acid, hydrochloric acid, and nitric acid, and organic acids such as formic acid and acetic acid can be used. Sulfuric acid is preferred.

The method of dehydration and filtration is not particularly limited, and various known methods can be used. Examples include centrifugal filtration, vacuum filtration, pressure filtration, and the like. Further, the drying method is not particularly limited, and various methods can be used.

2. Basic properties of colored resin particles The volume average particle diameter (Dv) of colored resin particles is preferably 5.0 to 8.0 μm, more preferably 6.0 to 7.5 μm. If the Dv of the colored resin particles is at least the above lower limit, the fluidity of the toner will improve, it will be easy to maintain excellent transferability, and high image density will be maintained; if it is below the above upper limit, the image will be Resolution can be improved.

Further, the ratio of the volume average particle diameter (Dv) to the number average particle diameter (Dn) (Dv/Dn) of the colored resin particles is preferably 1.00 to 1.20, more preferably 1.00 to 1.20. 00 to 1.18, more preferably 1.00 to 1.15. If Dv/Dn is 1.2 or less, transferability, image density, and resolution can all be maintained at high levels. The volume average particle size and number average particle size of the colored resin particles can be measured using, for example, a particle size analyzer (trade name: Multisizer, manufactured by Beckman Coulter).

The average circularity (Ca) of the colored resin particles is preferably from 0.97 to 1.00, more preferably from 0.98 to 1.00, from the viewpoint of image reproducibility. When the average circularity of the colored resin particles is 0.97 or more, fine line reproducibility of printing is excellent.
Here, circularity is defined as a value obtained by dividing the perimeter of a circle having the same projected area as the particle image by the perimeter of the projected image of the particle. The average circularity (Ca) is used as a simple method to quantitatively express the shape of particles, and is an index indicating the degree of unevenness of colored resin particles. The average circularity (Ca) shows 1 when the colored resin particles are perfectly spherical, and becomes a smaller value as the surface shape of the colored resin particles becomes more complex.
The average circularity (Ca) is determined by the following formula for calculating average circularity.

In the above formula, n is the number of particles whose circularity Ci was determined.
In the above formula, Ci is the circularity of each particle calculated by the following circularity calculation formula based on the circumferential length measured for each particle of the particle group with an equivalent circle diameter of 0.6 to 400 μm.
Calculation formula for circularity:
Circularity (Ci)=Perimeter of a circle equal to the projected area of a particle/Perimeter of a projected image of a particle In the above formula, fi is the frequency of particles with circularity Ci.
The circularity and average circularity can be measured using a flow type particle image analyzer "FPIA-3000" manufactured by Sysmex Corporation.

According to the manufacturing method of the present disclosure, the absolute value of the blow-off charge amount of the colored resin particles can be preferably set to 40 to 80 μc/g, more preferably 43 to 70 μc/g, and even more preferably can be between 45 and 65 μc/g.
Note that the blow-off charge amount of the colored resin particles is a value obtained by measuring the amount of triboelectric charge when the colored resin particles are mixed with carrier particles based on a blow-off method. As the carrier particles, it is preferable to use standard carrier EF-60 (product name, manufactured by Powder Tech, Mn-Mg-Sr-Fe system, spherical, without resin coating, particle size 60 nm). It is preferable to use a powder charge amount measuring device to measure the amount of charge, and for example, MODEL231TO Q/mMETER (model: manufactured by Trek Japan) can be preferably used.
In the present disclosure, the blow-off charge amount of the colored resin particles is the average value of each measurement value of 10 samples of the colored resin particles. Here, as the sample of colored resin particles, a predetermined amount of dried colored resin particles can be used. Further, the smaller the standard deviation of the average value of the blow-off charge amounts in the 10 samples of colored resin particles, the more excellent the colored resin particles are in charging uniformity. The standard deviation of the average value is preferably less than 6.0, more preferably less than 3.0.

3. External Addition Treatment Step The manufacturing method of the present disclosure preferably further includes a step of attaching an external additive to the surface of the colored resin particles. By including this step, the toner obtained by the manufacturing method of the present disclosure can be a one-component toner (developer) in which an external additive is attached to the surface of colored resin particles. Note that the one-component toner may be further mixed and stirred with carrier particles to form a two-component developer.

The external addition treatment step of adhering the external additive to the surface of the colored resin particles can be performed, for example, by mixing and stirring the colored resin particles together with the external additive.
The stirrer that performs the external addition treatment is not particularly limited as long as it is a stirring device that can attach the external additive to the surface of the colored resin particles, and examples include Henschel mixer (trade name, manufactured by Mitsui Mining Co., Ltd.), FM mixer. (:Product name, manufactured by Nippon Coke Industries Co., Ltd.), Super Mixer (:Product name, manufactured by Kawada Seisakusho Co., Ltd.), Q Mixer (:Product name, manufactured by Nippon Coke Industries Co., Ltd.), Mechano Fusion System (:Product name, manufactured by Hosokawa Micron Co., Ltd.) ), and a stirrer capable of mixing and stirring, such as Mechano Mill (trade name, manufactured by Okada Seiko Co., Ltd.).

As the external additive, one having an appropriate material and particle size can be selected from various inorganic fine particles and organic fine particles. External additives include, for example, inorganic fine particles such as silica, titanium oxide, aluminum oxide, zinc oxide, tin oxide, calcium carbonate, calcium phosphate, and cerium oxide; organic fine particles such as polymethyl methacrylate resin, silicone resin, and melamine resin. ; etc. Among these, inorganic fine particles are preferred, and among the inorganic fine particles, at least one kind of fine particles selected from silica and titanium oxide are preferred, and silica fine particles are particularly preferred.
In addition, although these external additives can be used individually, it is preferable to use two or more types in combination. Among these, it is preferable to use two or more types of silica fine particles having different particle sizes in combination.

The amount of the external additive added is usually 0.05 to 6 parts by weight, preferably 0.2 to 5 parts by weight, per 100 parts by weight of the colored resin particles. When the amount of the external additive added is at least the above lower limit value, it is possible to suppress the generation of transfer residue, and when it is below the above upper limit value, fogging can be suppressed.

4. Carbon black-containing toner for developing electrostatic images According to the manufacturing method of the present disclosure, when left for 24 hours in a normal temperature and normal humidity (N/N) environment with a temperature of 23° C. and a relative humidity of 50%, the amount of toner is 0.5 mg/ cm ² , 5% image density, it is possible to obtain a toner in which the image density of the black solid print on the 10th sheet is 1.20 or more, which is a more preferable implementation. In this embodiment, a toner having an image density of 1.30 or more can be obtained.

According to the manufacturing method of the present disclosure, both of a high temperature and high humidity (H/H) environment with a temperature of 35° C. and a relative humidity of 80% and a low temperature and low humidity (L/L) environment with a temperature of 10° C. and a relative humidity of 20% can be used. Also, it is possible to obtain a toner with a fog value of less than 1.6 after a printing durability test with 1,000 sheets of continuous printing and after a printing durability test with 10,000 sheets of continuous printing, which is more preferable. In the embodiment, it is possible to obtain a toner having the above-mentioned fog value of less than 0.8.
The printing durability test is conducted in the same manner as the printing durability test in Examples described later, and the fog value is determined in the same manner as the fog value in Examples described later.

The present disclosure will be described in more detail below with reference to Examples and Comparative Examples, but the present disclosure is not limited to these Examples. Note that parts and percentages are based on mass unless otherwise specified.

(Synthesis Example 1: Synthesis of sulfonic acid group-containing polymer (1))
In a 3 L reaction vessel, 900 parts of toluene, 83 parts of styrene, 14.5 parts of 2-ethylhexyl acrylate, 2.5 parts of 2-acrylamido-2-methylpropanesulfonic acid, and 2,2'-azobis(2,4- 2.4 parts of dimethylvaleronitrile) were added, and a copolymerization reaction was carried out at 80° C. for 8 hours while stirring. After the reaction was completed, the solvent was removed by freeze-drying to obtain a sulfonic acid group-containing polymer (1) having a weight average molecular weight of 18,000 and a glass transition temperature of 56.2°C. The copolymerization ratio of the sulfonic acid group-containing (meth)acrylamide monomer unit (2-acrylamide-2-methylpropanesulfonic acid unit) in the sulfonic acid group-containing polymer (1) was 2.5% by mass.

[Example 1]
(1) Step of preparing a polymerizable monomer composition The polymerizable monomers include 75 parts of styrene, 25 parts of butyl acrylate, and a polymethacrylate macromonomer (manufactured by Toagosei Kagaku Kogyo Co., Ltd., trade name "AA6") ) 1.5 parts, 12 parts of carbon black (DBP absorption: 66 mL/100 g, manufactured by Mitsubishi Chemical Corporation) as a coloring agent, and 1.0 mass % of quaternary ammonium base-containing acrylate monomer unit as a charge control resin. Polymerization by mixing 6.0 parts of styrene-acrylic polymer (styrene/acrylic resin, trade name: FCA-676P, manufactured by Fujikura Kasei Co., Ltd., Tg: 73°C, weight average molecular weight (Mw): 19,500) A mixture of monomers was obtained.
The obtained polymerizable monomer mixture was circulated 18 times at a rotor peripheral speed of 28 m/s using a comb-shaped coaxial ring type disperser (1) (manufactured by Eurotech, trade name: Cavitron). Dispersion processing was performed under the following conditions. In addition, in the above-mentioned disperser (1), the width of the slit portion of the rotor and stator is 0.05 to 6 mm, and the combination of the rotor and stator is arranged in one step along the axial direction of the drive shaft. The drive shaft was arranged in three concentric stages outward from the center of the drive shaft. In addition, the above-mentioned disperser (1) is arranged so that the slit width of the rotor and stator on the outside of the drive shaft is narrower than the slit width of the rotor and stator on the center side of the drive shaft. A combination with a stator was placed.

While stirring 118.3 parts of the polymerizable monomer mixture after dispersion treatment with a stirrer, 20 parts of pentaerythritol tetrastearate as a mold release agent, 1.0 part of tetraethylthiuram disulfide as a molecular weight regulator, and a crosslinking monomer were added. A polymerizable monomer composition was prepared by adding 0.8 parts of divinylbenzene and stirring for 10 minutes.

(2) Step of preparing a suspension On the other hand, add sodium hydroxide (alkali metal A dispersion of magnesium hydroxide colloid (poorly water-soluble metal hydroxide colloid) was prepared by gradually adding an aqueous solution in which 5 parts of hydroxide) was dissolved under stirring.

While stirring the magnesium hydroxide colloidal dispersion obtained above with a stirrer, the above polymerizable monomer composition was added, and after stirring for 10 minutes, t-butylperoxy-2-ethylbutyl as a polymerization initiator was added. Further, 5 parts of a rate (manufactured by Kayaku Akzo Co., Ltd., trade name "Trigonox 27") was added, and using the above-mentioned dispersing machine (1), high speed The polymerizable monomer composition was granulated by shear stirring to obtain a suspension in which droplets of the polymerizable monomer composition were dispersed.

(3) Step of forming colored resin particles A suspension in which droplets of the polymerizable monomer composition are dispersed is put into a reactor equipped with a stirring blade, and the temperature is raised to 90°C while stirring. A polymerization reaction was carried out. After the polymerization conversion rate reached almost 100%, the polymerization temperature was kept as it was, and 3 parts of methyl methacrylate, which is a polymerizable monomer for the shell, and 2,2'-azobis [2 0.1 part of -methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide] (manufactured by Wako Pure Chemical Industries, Ltd., trade name "VA086") was added, and the temperature was further heated at 90°C. The mixture was kept for 3 hours and then cooled with water to obtain an aqueous dispersion of colored resin particles having a core-shell structure. The pH of the resulting aqueous dispersion was 9.5.

(4) Washing, filtration, dehydration, and drying process While stirring the aqueous dispersion of colored resin particles obtained above, add sulfuric acid until the pH becomes 6 or less, and continue stirring at 25°C for 10 minutes. Acid cleaning was performed using Thereafter, water was separated by filtration, and then 500 parts of ion-exchanged water was added to form a slurry again, followed by stirring for 10 minutes to perform water washing. After repeating filtration, dehydration, and water washing several times, the colored resin particles were separated by filtration to obtain wet colored resin particles (1). The wet colored resin particles (1) were placed in a dryer and dried at a temperature of 40° C. for 3 days.

(5) External addition treatment step To 100 parts of the dried colored resin particles (1), 1 part of hydrophobically treated silica fine particles (manufactured by Cabot, product name: TG820F, number average primary particle diameter: 7 nm) and hydrophobic 1 part of treated silica fine particles (manufactured by Nippon Aerosil Co., Ltd., product name: NEA50, number average primary particle size: 35 nm) were added and mixed using a Henschel mixer to form the non-magnetic one-component toner of Example 1. Obtained.

[Examples 2 to 4]
In Example 1, in the above "(1) Step of preparing a polymerizable monomer composition", the conditions of the dispersion treatment by the above dispersing machine (1) were changed to the circumferential speed of the rotor and the number of circulations shown in Table 1. Except for the changes, colored resin particles (2) to (4) of Examples 2 to 4 were obtained in the same manner as in Example 1, and the colored resin particles (2) to (4) were treated with the above-described particles of Example 1. By carrying out the same external addition treatment as in "(5) External addition treatment step," non-magnetic one-component toners of Examples 2 to 4 were obtained.

[Example 5]
In Example 1, in the above "(1) Step of preparing a polymerizable monomer composition", quaternary ammonium base-containing acrylate monomer units were used as the charge control resin in place of 6.0 parts of FCA-676P. Styrene acrylic polymer (styrene/acrylic resin, trade name: FCA-592P, manufactured by Fujikura Kasei Co., Ltd., Tg: 82°C, weight average molecular weight (Mw): 12,000) containing 2.0% by mass 2.5 The colored resin particles (5) of Example 5 were obtained in the same manner as in Example 1, except that the colored resin particles (5) were subjected to the above-mentioned "(5) External addition treatment step" of Example 1. A non-magnetic one-component toner of Example 5 was obtained by carrying out the same external addition treatment as described in .

[Example 6]
In Example 1, in the above "(1) Step of preparing a polymerizable monomer composition", quaternary ammonium base-containing acrylate monomer units were used as the charge control resin in place of 6.0 parts of FCA-676P. The procedure was carried out in the same manner as in Example 1, except that 13.0 parts of styrene-acrylic polymer (styrene/acrylic resin, trade name: FCA-700P, manufactured by Fujikura Kasei Co., Ltd.) containing 0.5% by mass was used. The colored resin particles (6) of Example 6 were obtained, and by subjecting the colored resin particles (6) to the same external addition treatment as in the above "(5) External addition treatment step" of Example 1, a non-magnetic single component was obtained. The toner of Example 6 was obtained.

[Example 7]
In Example 1, the procedure was carried out in the same manner as in Example 1, except that the amount of carbon black added was changed from 12 parts to 14 parts in the above "(1) Step of preparing a polymerizable monomer composition". The colored resin particles (7) of Example 7 were obtained, and by subjecting the colored resin particles (7) to the same external addition treatment as in the above "(5) External addition treatment step" of Example 1, a non-magnetic single component was obtained. The toner of Example 7 was obtained.

[Example 8]
In Example 1, the sulfonic acid group-containing polymer obtained in Synthesis Example 1 was used in place of 6.0 parts of FCA-676P as the charge control resin in the above "(1) Step of preparing a polymerizable monomer composition". (1) Except for using 6.0 parts, the colored resin particles (8) of Example 8 were obtained in the same manner as in Example 1, and the colored resin particles (8) were added to the above "( 5) External addition treatment step'' to obtain a non-magnetic one-component toner of Example 8.

[Comparative example 1]
In Example 1, in the above "(1) Step of preparing a polymerizable monomer composition", a media type dispersion machine was used instead of the above dispersion machine (1) (manufactured by Eurotech, trade name: Cavitron). The colored resin particles (C1) of Comparative Example 1 were prepared in the same manner as in Example 1, except that a certain dispersing machine (2) (manufactured by Shinmaru Enterprises, product name: DYNO-MILL, KDL-PILOT type) was used. and subjected the colored resin particles (C1) to the same external addition treatment as in the above "(5) External addition treatment step" of Example 1 to obtain a non-magnetic one-component toner of Comparative Example 1. .

[Comparative Examples 2-3]
In Example 1, in the above-mentioned "(1) Step of preparing a polymerizable monomer composition", the conditions of the dispersion treatment by the above-mentioned disperser (1) were changed to the circumferential speed of the rotor and the number of circulations shown in Table 1. Except for the changes, colored resin particles (C2) to (C3) of Comparative Examples 2 to 3 were obtained in the same manner as in Example 1, and the colored resin particles (C2) to (C3) were treated with the above-described particles of Example 1. By performing the same external addition treatment as in "(5) External addition treatment step," non-magnetic one-component toners of Comparative Examples 2 and 3 were obtained.

[Comparative example 4]
In Example 1, in the above "(1) Step of preparing a polymerizable monomer composition", 6.0 parts of FCA-676P as a charge control resin was not added to the polymerizable monomer mixture, and the dispersion was carried out. 6.0 parts of FCA-676P as a charge control resin was added to the treated polymerizable monomer mixture together with a mold release agent, a molecular weight regulator, and a crosslinking monomer, and further dispersed using the above-mentioned dispersing machine (1). Colored resin particles (C4) of Comparative Example 4 were obtained in the same manner as in Example 1, except that the treatment conditions were changed to the circumferential speed of the rotor and the number of circulation shown in Table 1. C4) was subjected to the same external addition treatment as in the above-mentioned "(5) External addition treatment step" of Example 1 to obtain a non-magnetic one-component toner of Comparative Example 4.

[Comparative example 5]
In Example 1, in the above "(1) Step of preparing a polymerizable monomer composition," BONTRON (registered), which is a positively chargeable charge control agent, was used in place of 6.0 parts of charge control resin FCA-676P. Colored resin particles (C5) of Comparative Example 5 were obtained in the same manner as in Example 1, except that 2.0 parts of trademark) N-21 (product name, manufactured by Orient Chemical Industry Co., Ltd., azine compound) was used. Then, the colored resin particles (C5) were subjected to the same external addition treatment as in the above-mentioned "(5) External addition treatment step" of Example 1, thereby obtaining a non-magnetic one-component toner of Comparative Example 5.

[Comparative example 6]
In Example 1, in the above "(1) Step of preparing a polymerizable monomer composition", a cyan colorant (manufactured by Dainippon Ink and Chemicals, trade name "FASTOGEN Blue GCTF") was used instead of 12 parts of carbon black. Comparative Example 6 was carried out in the same manner as in Example 1, except that the conditions for the dispersion treatment by the dispersion machine (1) were changed to the circumferential speed of the rotor and the number of circulations shown in Table 1. A comparative example of a non-magnetic single component was obtained by obtaining colored resin particles (C6) and subjecting the colored resin particles (C6) to the same external addition treatment as in the above "(5) External addition treatment step" of Example 1. 6 toner was obtained.

[Comparative Example 7]
In Example 1, in the above "(1) Step of preparing a polymerizable monomer composition", a cyan colorant (manufactured by Dainippon Ink and Chemicals, trade name "FASTOGEN Blue GCTF") was used instead of 12 parts of carbon black. ''), the conditions for the dispersion treatment using the dispersion machine (1) were changed to the circumferential speed of the rotor and the number of circulations shown in Table 1, and the polymerizable monomer mixture was further added with a charge control resin. Without adding 6.0 parts of FCA-676P, 6.0 parts of FCA-676P as a charge control resin was added to the polymerizable monomer mixture after dispersion treatment along with a mold release agent, a molecular weight regulator, and a crosslinking monomer. The colored resin particles (C7) of Comparative Example 7 were obtained in the same manner as in Example 1, except that the above "(5) External addition treatment step" of Example 1 was added to the colored resin particles (C7). A non-magnetic one-component toner of Comparative Example 7 was obtained by carrying out the same external addition treatment.

[evaluation]
The DBP absorption amount of the carbon black used in each example was measured in accordance with "How to determine oil absorption amount" of ISO4656 (JIS K6217-4:2008).
The number of cycles of dispersion treatment performed on the polymerizable monomer mixture in each example was calculated using the above formula (I).
The following measurements and evaluations were performed on the dried colored resin particles and toners produced in each Example and each Comparative Example. The measurement results and evaluation results are shown in Table 1.

(1) Volume average particle size of colored resin particles The volume average particle size of the colored resin particles was measured using a particle size measuring device (manufactured by Beckman Coulter, trade name: Multisizer). The measurement using this multisizer was carried out under the following conditions: aperture diameter: 100 μm, dispersion medium: Isoton II (trade name), concentration 10%, and number of particles measured: 100,000.
Specifically, about 0.1 g of dried colored resin particles was weighed, placed in a beaker, and 0.1 mL of a surfactant aqueous solution (manufactured by Fujifilm, trade name: Drywell) was added as a dispersant. Further, 10 to 30 mL of Isoton II was added to the beaker, and the mixture was dispersed for 3 minutes using a 20 W (Watt) ultrasonic dispersion machine, and then measured using the above-mentioned particle size measuring machine.

(2) Blow-off charge amount and charge uniformity of colored resin particles 0.25 g of colored resin particles after drying and ferrite carrier (EF-60 (: product name, manufactured by Powder Tech Co., Ltd., Mn-Mg-Sr-Fe system, Spherical shape, no resin coating, particle size 60 nm)) was placed in a glass container with a volume of 30 mL (inner dimensions: bottom diameter 30 mm, height 50 mm), and stirred at 160 rpm for 30 minutes using a roller stirrer. The triboelectrification treatment was performed in an environment of 23° C. and 50% relative humidity. 0.2 g of the mixture of colored resin particles and ferrite carrier after the triboelectric charging treatment was put into a Faraday gauge, and nitrogen gas was charged using a blow-off powder charge measuring device (Model: MODEL231TO Q/mMETER, manufactured by Trek Japan). Blow-off was performed for 30 seconds at a pressure of 0.098 MPa, and the blow-off charge amount (μC/g) of the colored resin particles was measured.
The above measurement was performed once for each of 10 samples for each Example or Comparative Example (N=10), and the average value and standard deviation of each measurement value were determined. The average value was taken as the blow-off charge amount of the colored resin particles, and the charge uniformity of the colored resin particles was evaluated based on the standard deviation according to the following evaluation criteria.
(Charging uniformity evaluation criteria)
A: Standard deviation is less than 3.0 B: Standard deviation is 3.0 or more and less than 6.0 C: Standard deviation is 6.0 or more

(3) Image density For the toners obtained in Examples 1 to 7 and Comparative Examples 1 to 7, a commercially available non-magnetic one-component development type positively charged toner printer (printing speed: 20 sheets/min) was used. After filling the toner cartridge of the developing device with toner, printing paper was set and left for 24 hours in a normal temperature and normal humidity (N/N) environment with a temperature of 23° C. and a relative humidity of 50%. Thereafter, the amount of toner supplied onto the developing roll during solid printing was fixed at one point at 0.5 mg/cm ² , and continuous printing was performed at an image density of 5%. Solid black printing (100% image density) was performed on the 10th sheet of printing paper, and the image density was measured using a Macbeth type reflection type image density measuring device.
Regarding the toner obtained in Example 8, in the image density measurement method of Examples 1 to 7 and Comparative Examples 1 to 7 described above, a commercially available non-magnetic one-component development method was used instead of the above-mentioned positively charged toner printer. Image density was measured in the same manner as in Examples 1 to 7 and Comparative Examples 1 to 7, except that a negatively charged toner printer (printing speed: 20 sheets/min) was used.
Evaluation was made according to the following evaluation criteria based on the measured value of image density.
(Image density evaluation criteria)
A: Image density is 1.30 or more B: Image density is 1.20 or more and less than 1.30 C: Image density is less than 1.20

(4) Fog The following printing was performed under a high temperature, high humidity (H/H) environment with a temperature of 35°C and a relative humidity of 80%, and under a low temperature and low humidity (L/L) environment with a temperature of 10°C and a relative humidity of 20%. A durability test was conducted.
(Printing durability test)
For the toners obtained in Examples 1 to 7 and Comparative Examples 1 to 7, a commercially available non-magnetic one-component development system positively charged toner printer (printing speed: 20 sheets/min) was used, and the toner cartridge of the developing device was used. After filling with toner, printing paper was set, and after being left for 24 hours under a predetermined environment, continuous printing was performed at 5% image density under the same environment. After the 1,000th continuous print (initial period) and after the 10,000th sheet (after durability), solid white printing was performed, and printing was stopped in the middle of the solid white printing. After development, the toner in the non-image area on the photoreceptor was peeled off with an adhesive tape, and the adhesive tape was attached to a new printing paper. The color tone of the new printing paper to which the adhesive tape was attached was measured using a Macbeth type reflection type image density measuring device, and each color tone was expressed as coordinates in Lab space.
Regarding the toner obtained in Example 8, in the color tone measurement methods of Examples 1 to 7 and Comparative Examples 1 to 7 described above, a commercially available non-magnetic one-component developing type printer was used instead of the above-mentioned positively charged toner printer. Initial and post-durability color tones were measured in the same manner as in Examples 1 to 7 and Comparative Examples 1 to 7, except that a negatively charged toner printer (printing speed: 20 sheets/min) was used. expressed as the coordinates of
The color tone of the printing paper to which an unused adhesive tape was attached was measured using a Macbeth-type reflection type image density measuring device, and the color tone expressed as coordinates in Lab space was used as a reference sample.
The color difference ΔE between the color tone of the measurement sample using the toner of Example or Comparative Example and the color tone of the reference sample was calculated as a fog value, and evaluated according to the following evaluation criteria. A smaller fog value indicates less fog.
(Fog evaluation criteria)
A: Fog value (ΔE) is less than 0.8 B: Fog value (ΔE) is 0.8 or more and less than 1.6 C: Fog value (ΔE) is 1.6 or more

In Table 1, "CB" means carbon black and "cyan" means cyan colorant. Moreover, "macromonomer" means polymethacrylic acid ester macromonomer (manufactured by Toagosei Kagaku Kogyo Co., Ltd., trade name "AA6"), and "crosslinkable monomer" means divinylbenzene.

[Consideration]
In Comparative Example 1, in the process of preparing the polymerizable monomer composition, a media-type dispersion machine was used instead of a comb-teeth type coaxial ring-type dispersion machine, so the charging uniformity of the colored resin particles was poor. When an image was formed, fogging was likely to occur both initially and after durability under both the H/H environment and the L/L environment. In Comparative Example 1, it is considered that media fragments were mixed into the toner particles, resulting in a decrease in charging characteristics and a decrease in image characteristics.
In Comparative Example 2, in the process of preparing the polymerizable monomer composition, the peripheral speed of the rotor of the dispersion machine exceeded 60 m/s, so the amount of blow-off charge of the colored resin particles was insufficient, and the image When formed, the image density was insufficient, and fogging was likely to occur after durability in both H/H and L/L environments. In Comparative Example 2, it is thought that the dispersion of carbon black was insufficient due to pressure loss caused by the peripheral speed of the rotor of the dispersion machine being too high, resulting in a decrease in charging characteristics and a decrease in image characteristics. It will be done.
In Comparative Example 3, in the step of preparing the polymerizable monomer composition, the peripheral speed of the rotor of the dispersion machine was less than 15 m/s, so the amount of blow-off charge of the colored resin particles was insufficient, and the image When formed, the image density was insufficient, and fogging was likely to occur after durability in both H/H and L/L environments. In Comparative Example 3, it is thought that the dispersion of carbon black was insufficient due to insufficient energy due to the peripheral speed of the rotor of the dispersion machine being too slow, resulting in a decrease in charging characteristics and a decrease in image characteristics. It will be done.
In Comparative Example 4, in the step of preparing the polymerizable monomer composition, the dispersion treatment was performed without adding the charge control resin to the polymerizable monomer mixture, and the charge control resin was added after the dispersion treatment, so that the colored resin The blow-off charge amount of the particles is insufficient, the charging uniformity of the colored resin particles is poor, and when an image is formed, the image density is insufficient, and both under H/H environment and L/L environment. Also, initial fogging and fogging after durability were likely to occur. In Comparative Example 4, it is thought that the dispersion of carbon black was performed in the absence of a charge control agent, resulting in insufficient dispersion of carbon black, resulting in a decrease in charging characteristics and a decrease in image characteristics. .
In Comparative Example 5, in the step of preparing a polymerizable monomer composition, an azine compound (BONTRON (registered trademark) N-71) as a charge control agent was added to the polymerizable monomer mixture instead of the charge control resin. As a result, the amount of blow-off charge of the colored resin particles was insufficient, the uniformity of charge of the colored resin particles was poor, and when an image was formed, it was difficult to carry out under the H/H environment. Fog was likely to occur after durability in both the L/L and L/L environments. In Comparative Example 5, dispersion of carbon black was performed in the presence of a charge control agent different from the charge control resin, and as a result, the dispersion of carbon black was insufficient, resulting in decreased charging characteristics and image characteristics. It is thought that this has decreased.

In Comparative Examples 6 and 7, a cyan colorant was used instead of carbon black as a colorant. In Comparative Example 6, the charge control resin was added during the dispersion treatment, and in Comparative Example 7, the charge control resin was added after the dispersion treatment. As a result, there was almost no difference between the evaluation results of Comparative Examples 6 and 7, and the charging uniformity of the colored resin particles was poor, and when forming an image, it was found that both under H/H environment and L/L environment. Also, initial fogging and fogging after durability were likely to occur. This revealed that when the colorant does not contain carbon black, even if the colorant is dispersed in the presence of a charge control resin, the effect of improving image characteristics cannot be obtained. For colorants different from carbon black, it is difficult to obtain the dispersibility improvement effect of a charge control resin, so even if dispersion treatment is performed in the presence of a charge control resin, the dispersibility of the colorant will not improve, and the colorant's dispersibility will not improve. It is estimated that there was almost no difference in the evaluation results of Comparative Examples 6 and 7 because the dispersion state was the same when the dispersion treatment was performed in the presence of the charge control resin and when the charge control resin was added after the dispersion treatment. be done.

On the other hand, in Examples 1 to 8, in the step of preparing a polymerizable monomer composition, a polymerizable monomer containing at least a polymerizable monomer, carbon black as a coloring agent, and a charge control resin as a charge control agent was used. The carbon black was dispersed in the polymerizable monomer by performing a dispersion treatment on the mixture using a comb-shaped coaxial ring type dispersing machine at a rotor peripheral speed of 15 to 60 m/s. In Examples 1 to 8, the amount of blow-off charge of the colored resin particles was sufficient, the charge uniformity was excellent, the image density was good when an image was formed, and it was found that the amount of blow-off charge of the colored resin particles was sufficient, the image density was good when an image was formed, and the amount of blow-off charge was sufficient, the charge uniformity was excellent, the image density was good when an image was formed, and Fog was also less likely to occur. As described above, in Examples 1 to 8, images with excellent image characteristics could be formed by dispersing carbon black in the polymerizable monomer through dispersion treatment without using media particles.

1 Tank 2 Dispersion machine (casing)
3 Cooling jacket 4 Rotor 5 Stator 6 Drive shaft 7 Dispersion liquid inflow path 8 Dispersion liquid circulation path 9 Dispersion liquid discharge path

Claims (7)

preparing a polymerizable monomer composition containing at least a polymerizable monomer, a colorant, and a charge control agent;
A step of granulating the polymerizable monomer composition in an aqueous dispersion medium to prepare a suspension in which droplets of the polymerizable monomer composition are dispersed;
A method for producing a toner, comprising a step of forming colored resin particles by subjecting the suspension to a polymerization reaction, the method comprising:
In the step of preparing the polymerizable monomer composition, the composition contains at least a polymerizable monomer, carbon black as a colorant, and a charge control resin as a charge control agent , and the charge control resin contains a quaternary ammonium base-containing ( A styrene acrylic polymer containing a meth)acrylate monomer unit, wherein the copolymerization ratio of the quaternary ammonium base-containing (meth)acrylate monomer unit in the styrene acrylic polymer is 0.1% by mass or more and 3.0% by mass. % or less , a dispersing machine having a combination of a rotor and a stator, both of which are comb-shaped rings, are arranged concentrically, and the circumferential speed of the outer peripheral end of the rotor is A method for producing a carbon black-containing toner for developing an electrostatic image, the method comprising carrying out a dispersion treatment at a speed of 15 m/s or more and 60 m/s or less. The electrostatic charge according to claim 1, wherein the content of the carbon black in the polymerizable monomer composition is 8 parts by mass or more and 15 parts by mass or less with respect to 100 parts by mass of the polymerizable monomer. A method for producing a carbon black-containing toner for image development. In the step of preparing the polymerizable monomer composition, the dispersion treatment is performed by repeatedly circulating the polymerizable monomer mixture by introducing it into the dispersion machine and then discharging it from the dispersion machine. Item 3. The method for producing a carbon black-containing toner for developing electrostatic images according to item 1 or 2 . The method for producing a carbon black-containing toner for developing electrostatic images according to any one of claims 1 to 3 , wherein the carbon black has an absorption amount of dibutyl phthalate of 40 mL/100 g or more and 100 mL/100 g or less. The method for producing a carbon black-containing toner for developing an electrostatic image according to any one of claims 1 to 4 , which comprises producing a black toner containing carbon black. 1. In the step of preparing the polymerizable monomer composition, the dispersion treatment is performed using only a dispersing machine having a combination of a rotor and a stator, both of which are comb-shaped rings, arranged concentrically. 5. The method for producing a carbon black-containing toner for developing electrostatic images according to any one of items 5 to 5 . In the step of preparing the suspension, the polymerizable monomer composition is dispersed into an aqueous dispersion medium using a disperser having a combination of a rotor and a stator, both of which are comb-shaped rings, arranged concentrically. The method for producing a carbon black-containing toner for developing an electrostatic image according to any one of claims 1 to 6 , wherein the toner is granulated in a toner containing carbon black.

Images