WO2011105243A1

WO2011105243A1 - Magenta toner

Info

Publication number: WO2011105243A1
Application number: PCT/JP2011/053029
Authority: WO
Inventors: 龍史太田
Original assignee: 日本ゼオン株式会社
Priority date: 2010-02-26
Filing date: 2011-02-14
Publication date: 2011-09-01
Also published as: JP5641040B2; JPWO2011105243A1

Abstract

Provided is a magenta toner combining high light-fastness and high image density. The magenta toner contains magenta colored resin granules containing a binder resin and magenta pigments. C.I. pigment red 31 and C.I. pigment red 269 are contained as the magenta pigments.

Description

Magenta toner

The present invention relates to a magenta toner having both high light resistance and high image density.

In an image forming apparatus such as an electrophotographic apparatus or an electrostatic recording apparatus, an electrostatic latent image formed on a photoreceptor is first developed with toner. Next, the formed toner image is transferred onto a transfer material such as paper as necessary, and then fixed by various methods such as heating, pressurization, or solvent vapor.
In such image forming apparatuses, digital full-color copiers and digital full-color printers have been put into practical use. A digital full-color copying machine separates a color image original with blue, green, and red filters, and then converts an electrostatic latent image having a dot diameter of 20 to 70 μm corresponding to the original color original into yellow, magenta, Development is performed using cyan and black toners, and a full-color image is formed using a subtractive color mixing effect.

In recent years, the demand for higher image quality and higher definition of this full-color image has been increasing. In particular, in order to improve color reproducibility, it is desired that printing can be performed with a hue equivalent to printing with ink. Conventionally, a quinacridone colorant, a thioindigo colorant, a xanthene colorant, a monoazo colorant, a perylene colorant, a diketopyrrolopyrrole colorant, and the like are used alone or in combination for the magenta toner. It has been known. Among these, from the viewpoint of excellent weather resistance, heat resistance, and transparency, use of a quinacridone colorant in combination with another magenta colorant has been studied.

Patent Document 1 proposes a magenta toner in which a quinacridone colorant and a monoazo colorant are used in combination. I. Pigment red 122, C.I. I. Pigment violet 19 and C.I. I. A magenta toner containing CI Pigment Red 150 is disclosed.

On the other hand, studies have been made to use two or more monoazo colorants, which are other magenta colorants, without using quinacridone colorants.
In Patent Document 2, C.I. I. Pigment red 31 and C.I. I. Magenta toner containing CI Pigment Red 150, and C.I. I. Pigment red 150 and C.I. I. A magenta toner containing CI Pigment Red 269 is disclosed.

JP 2003-202706 A JP 2005-107147 A

The magenta toner disclosed in Patent Document 1 has improved light resistance as compared with other pigments, but tends to decrease the image density. Therefore, it is necessary to use a large amount of the pigment, and therefore the cost is high. On the other hand, the magenta toner disclosed in Patent Document 2 tends to decrease the light resistance although the image density is improved.
Further, the magenta toner disclosed in the above-mentioned Patent Document 1 or Patent Document 2 is such that the toner is ejected from the toner cartridge after being left at a high temperature, or the durability under a high-temperature and high-humidity environment is poor. There was also a problem with print quality.
The present invention has been accomplished in view of the above circumstances, and an object thereof is to provide a magenta toner having both high light resistance and high image density.

The magenta toner of the present invention is a magenta toner containing magenta colored resin particles containing a binder resin and a magenta pigment. I. Pigment red 31 and C.I. I. Pigment Red 269 is contained.

The magenta toner having such a configuration is C.I. I. Pigment red 31 and C.I. I. Since both pigment red 269 is contained, both high light resistance and high image density can be achieved.

In the present invention, when the total content of the magenta pigment is 100% by mass, the C.I. I. Pigment Red 31 is contained in an amount of 5 to 40% by mass, and C.I. I. The content ratio of Pigment Red 269 is preferably 60 to 95% by mass.

The magenta toner having such a configuration is C.I. I. Pigment red 31 and C.I. I. Since each pigment red 269 is contained in an appropriate ratio, both high light resistance and high image density can be achieved.

In the present invention, as the magenta pigment, C.I. I. Pigment Red 150 and C.I. when the total content of the magenta pigment is 100% by mass. I. It is preferable that the content rate of the pigment red 150 is 35 mass% or less.

Magenta toner having such a configuration is further described in C.I. I. Since the pigment red 150 is contained at an appropriate ratio, the image density can be further increased.

In the present invention, the magenta pigment is preferably a solid solution pigment.

In the present invention, it is preferable to contain 100 parts by mass of the binder resin and 1 to 10 parts by mass of the magenta pigment.

In the present invention, the magenta colored resin particles may further contain a charge control resin.

In the present invention, the magenta colored resin particles preferably have a core-shell structure.

The magenta toner of the present invention is C.I. I. Pigment red 31 and C.I. I. Since both pigment red 269 is contained, both high light resistance and high image density can be achieved.

Hereinafter, the production method of magenta colored resin particles and the magenta colored resin particles obtained by the production method will be described in order.

1. Production method of magenta colored resin particles Generally, the production method of colored resin particles is largely divided into dry methods such as a pulverization method and wet methods such as an emulsion polymerization aggregation method, a dispersion polymerization method, a suspension polymerization method, and a dissolution suspension method. A wet method is preferable because a toner excellent in printing characteristics such as fine line reproducibility is easily obtained. Among the wet methods, a polymerization method such as an emulsion polymerization aggregation method, a dispersion polymerization method, and a suspension polymerization method is preferable because a toner having a relatively small particle size distribution on the order of microns can be easily obtained. The turbid polymerization method is more preferable.

The emulsion polymerization aggregation method is a method for producing colored resin particles by polymerizing emulsified polymerizable monomers to obtain a resin fine particle emulsion and aggregating it with a colorant dispersion or the like. The dissolution suspension method produces droplets of a solution in which toner components such as a binder resin and a colorant are dissolved or dispersed in an organic solvent in an aqueous medium, and the organic solvent is removed to produce colored resin particles. It is a method to do. In the present invention, the above-mentioned known methods can be used.

The magenta colored resin particles of the present invention can be produced by employing a wet method or a dry method. When the colored resin particles are produced by employing the (A) suspension polymerization method which is preferable among the wet methods or the typical (B) pulverization method among the dry methods, the following process is performed.

(A) Suspension polymerization method (A-1) Preparation step of polymerizable monomer composition First, polymerizable monomers, magenta pigments, charge control agents, and other release agents if necessary The polymerizable monomer composition is prepared by mixing and dissolving the additive. The mixing at the time of preparing the polymerizable monomer composition is performed using, for example, a media type dispersing machine.

In the present invention, the polymerizable monomer means a monomer having a polymerizable functional group, and the polymerizable monomer is polymerized to become a binder resin. A monovinyl monomer is preferably used as the main component of the polymerizable monomer. Examples of the monovinyl monomer include styrene; styrene derivatives such as vinyl toluene and α-methylstyrene; acrylic acid and methacrylic acid; methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, acrylic acid 2 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; acrylamide And amide compounds such as methacrylamide; olefins such as ethylene, propylene, and butylene; and the like. These monovinyl monomers can be used alone or in combination of two or more.
Of the monovinyl monomers, styrene, styrene derivatives, acrylic acid esters, and methacrylic acid esters are preferably used.

In order to improve the storage stability (blocking resistance) of the toner as a part of the polymerizable monomer, it is preferable to use any crosslinkable polymerizable monomer together with the monovinyl monomer. A crosslinkable polymerizable monomer refers to a monomer having two or more polymerizable functional groups. Examples of the crosslinkable polymerizable monomer include aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene, and derivatives thereof; ethylenically unsaturated carboxylic acid esters such as ethylene glycol dimethacrylate and diethylene glycol dimethacrylate; N , N-divinylaniline, and divinyl compounds such as divinyl ether; compounds having three or more vinyl groups such as trimethylolpropane trimethacrylate and dimethylolpropane tetraacrylate; These crosslinkable polymerizable monomers may be used alone or in combination of two or more.
In the present invention, it is desirable to use the crosslinkable polymerizable monomer in a proportion of usually 0.1 to 5 parts by mass, preferably 0.3 to 2 parts by mass with respect to 100 parts by mass of the monovinyl monomer. .

Further, as a part of the polymerizable monomer, it is preferable to use an arbitrary macromonomer together with the monovinyl monomer in order to improve the balance between the storage stability of the toner and the low-temperature fixability. The macromonomer means a reactive oligomer or polymer having a polymerizable carbon-carbon unsaturated bond at the end of the molecular chain and having a number average molecular weight (Mn) of usually 1,000 to 30,000. . As the macromonomer, it is preferable to use an oligomer or polymer having a Tg higher than the glass transition temperature (Tg) of a polymer (binder resin) obtained by polymerizing a polymerizable monomer.
In the present invention, the proportion of the macromonomer is usually 0.01 to 10 parts by weight, preferably 0.03 to 5 parts by weight, and more preferably 0.1 to 2 parts by weight with respect to 100 parts by weight of the monovinyl monomer. It is desirable to use in.

As the magenta pigment, C.I. is a kind of monoazo pigment. I. Pigment red 31 and C.I. I. Pigment Red 269 is used.
The monoazo pigment has a molecular skeleton as shown in the following general formula (1).

(In the general formula (1), R ¹ to R ³ each represents a substituent selected from the group consisting of a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a nitro group, an anilide, and a sulfamoyl group. R ⁴ Represents a substituent selected from the group consisting of a hydroxyl group, an amino group, and the substituents shown below, wherein R ⁵ to R ⁸ in the substituents shown below are a hydrogen atom, a halogen atom, and an alkyl group, respectively. And a substituent selected from the group consisting of an alkoxy group and a nitro group.)

C. I. The chemical structure of Pigment Red 31 (hereinafter sometimes referred to as PR-31) is represented by the following formula (2).

C. I. The chemical structure of Pigment Red 269 (hereinafter sometimes referred to as PR-269) is represented by the following formula (3).

The magenta toner of the present invention is P.I. R-31 and P.I. Since R-269 is contained together, both high light resistance and high image density can be achieved. P.P. R-31 and P.I. By using R-269 together, ejection after being left at high temperature is suppressed, and the durability performance in a high temperature and high humidity (H / H) environment is improved.

When the total content of the magenta pigment is 100% by mass, P.I. The content of R-31 is 5 to 40% by mass; The content of R-269 is preferably 60 to 95% by mass. P. When the content ratio of R-31 is less than 5% by mass, it is difficult to keep the image density high. P. When the content ratio of R-269 is less than 60% by mass, high light resistance may not be maintained.
When the total content of the magenta pigment is 100% by mass, P.I. The content of R-31 is 5 to 35% by mass; The content of R-269 is particularly preferably 65 to 95% by mass. The content of R-31 is 10 to 35% by mass; More preferably, the content of R-269 is 65 to 90% by mass.

As a magenta pigment, C.I. I. It is preferable to use CI Pigment Red 150. C. I. The chemical structure of Pigment Red 150 (hereinafter sometimes referred to as PR-150) is represented by the following formula (4).

In the present invention, as a magenta pigment, P.I. By using R-150, a higher image density can be realized.
When the total content of the magenta pigment is 100% by mass, P.I. The content of R-150 is preferably 35% by mass or less. P. Assuming that the content of R-150 exceeds 35% by mass, P.I. Since the content ratio of R-150 is too high, P.I. The content of R-269 may be kept low, and as a result, high light resistance may not be maintained.
P. In the case of using R-150, when the total content of magenta pigment is 100% by mass, P.I. R-31, P.I. R-269 and P.I. The content ratios of R-150 are more preferably 5 to 35% by mass, 60 to 90% by mass and 5 to 30% by mass, respectively, and 10 to 30% by mass, 60 to 80% by mass and 10 to 30% by mass, respectively. % Is more preferable.

The magenta pigment is preferably a solid solution pigment.
A solid solution refers to a solid in which another substance enters a substance irregularly in units of atoms and molecules.
Since two or more types of monoazo magenta pigments are solid solutions in the magenta pigment toner, different monoazo magenta pigments can be mixed from a molecular unit to a microcrystalline unit. Therefore, the coexistence effect based on the interaction between different monoazo magenta pigments gives a color developability that is higher than the original color developability of the individual monoazo magenta pigments, or different monoazo magenta pigments mutually produce pigment crystals. By suppressing the growth of the toner particles, it can be presumed that desirable color developability is imparted to the toner particles, for example, because the pigment particles have a shape suitable for use as a toner.

In the present invention, the magenta pigment is preferably contained in an amount of 1 to 10 parts by mass with respect to 100 parts by mass of the binder resin. If this amount is small, the image density may be low, and conversely if it is large, the fixability may be lowered. Therefore, in the present invention, the magenta pigment is preferably used in a ratio of preferably 1 to 10 parts by mass with respect to 100 parts by mass of the monovinyl monomer.

As another additive, a release agent is preferably used in order to improve the releasability of the toner from the fixing roll.
The release agent is not particularly limited as long as it is generally used as a release agent for toner. For example, polyolefin waxes such as low molecular weight polyethylene, low molecular weight polypropylene, and low molecular weight polybutylene; candelilla, carnauba Natural waxes such as wax, rice, 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 hexami State, dipentaerythritol hexa palmitate, and polyhydric alcohol ester compounds such as dipentaerythritol esters such as dipentaerythritol hexa laurate; and the like. These release agents may be used alone or in combination of two or more.
In the present invention, it is desirable to use the release agent at a ratio of usually 0.1 to 30 parts by weight, preferably 1 to 20 parts by weight, with respect to 100 parts by weight of the monovinyl monomer. If this amount is small, sufficient releasability may not be obtained. Conversely, if the amount is large, toner preservability may be reduced.

As other additives, a positively or negatively chargeable charge control agent can be used to improve the chargeability of the toner.
The charge control agent is not particularly limited as long as it is generally used as a charge control agent for toner, but among charge control agents, the compatibility with the polymerizable monomer is high, and stable chargeability. (Charge stability) can be imparted to the toner particles, and therefore a positively or negatively chargeable charge control resin is preferable. Further, from the viewpoint of obtaining a positively chargeable toner, a positively chargeable charge control resin is preferable. More preferably used.
Examples of positively chargeable charge control agents include nigrosine dyes, quaternary ammonium salts, triaminotriphenylmethane compounds and imidazole compounds, polyamine resins as charge control resins that are preferably used, and quaternary ammonium group-containing copolymers. Examples thereof include a polymer and a quaternary ammonium base-containing copolymer.
Examples of negatively chargeable charge control agents include azo dyes containing metals such as Cr, Co, Al, and Fe, salicylic acid metal compounds and alkylsalicylic acid metal compounds, and sulfonic acids as charge control resins that are preferably used. Examples thereof include a group-containing copolymer, a sulfonate group-containing copolymer, a carboxylic acid group-containing copolymer, and a carboxylate group-containing copolymer.
In the present invention, it is desirable to use the charge control agent in a proportion of usually 0.01 to 10 parts by mass, preferably 0.03 to 8 parts by mass with respect to 100 parts by mass of the monovinyl monomer. If the addition amount of the charge control agent is less than 0.01 parts by mass, fog may occur. On the other hand, when the addition amount of the charge control agent exceeds 10 parts by mass, printing stains may occur.

It is preferable to use a molecular weight modifier as another additive.
The molecular weight regulator is not particularly limited as long as it is generally used as a molecular weight regulator for toners. For example, t-dodecyl mercaptan, n-dodecyl mercaptan, n-octyl mercaptan, 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, And thiuram disulfides such as N′-dioctadecyl-N, N′-diisopropylthiuram disulfide; These molecular weight modifiers may be used alone or in combination of two or more.
In the present invention, it is desirable to use the molecular weight adjusting agent in a proportion of usually 0.01 to 10 parts by mass, preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the monovinyl monomer.

(A-2) Suspension step for obtaining a suspension (droplet formation step)
The polymerizable monomer composition obtained through the above-described (A-1) polymerizable monomer composition preparation step is suspended in an aqueous dispersion medium and suspended (polymerizable monomer composition dispersion). Liquid). Here, the suspension means that droplets of the polymerizable monomer composition are formed in an aqueous dispersion medium. Dispersion treatment for forming droplets is, for example, an in-line type emulsifying disperser (manufactured by Ebara Manufacturing Co., Ltd., trade name: Ebara Milder), a high-speed emulsifying / dispersing machine (manufactured by Special Machine Industries Co., Ltd., trade name: TK , Homomixer MARK II type) and the like, which can be vigorously stirred.

In the present invention, it is preferable to use a dispersion stabilizer in the aqueous dispersion medium in order to improve the particle diameter control and the circularity of the colored resin particles in the formation of droplets.
The aqueous dispersion medium may be water alone, but can also be used in combination with a solvent that is soluble in water, such as lower alcohol and lower ketone.

Examples of the dispersion stabilizer 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 and metal compounds such as metal hydroxides such as aluminum hydroxide, magnesium hydroxide, and ferric hydroxide; water-soluble polymer compounds such as polyvinyl alcohol, methyl cellulose, and gelatin; anionic surfactants , Organic polymer compounds such as nonionic surfactants and amphoteric surfactants;

Among the above dispersion stabilizers, a dispersion stabilizer containing a colloid of a hardly water-soluble metal hydroxide (a hardly water-soluble inorganic compound) that is soluble in an acid solution is preferably used. The dispersion stabilizers can be used alone or in combination of two or more.
The addition amount of the dispersion stabilizer is preferably 0.1 to 20 parts by mass, more preferably 0.2 to 10 parts by mass with respect to 100 parts by mass of the polymerizable monomer.

Examples of the polymerization initiator used for the polymerization of the polymerizable monomer composition include inorganic persulfates such as potassium persulfate and ammonium persulfate; 4,4′-azobis (4-cyanovaleric acid), 2 2,2′-azobis (2-methyl-N- (2-hydroxyethyl) propionamide), 2,2′-azobis (2-amidinopropane) dihydrochloride, 2,2′-azobis (2,4-dimethylvalero) Nitrile), and azo compounds such as 2,2′-azobisisobutyronitrile; di-t-butyl peroxide, benzoyl peroxide, t-butyl peroxy-2-ethylhexanoate, t-hexyl peroxy -2-Ethylhexanoate, t-butyl peroxypivalate, diisopropyl peroxydicarbonate, di-t-butyl peroxy Sofutareto, and t- butyl organic peroxides such as peroxy isobutyrate; and the like. Among these, an organic peroxide is preferably used. When an organic peroxide is used, a toner with less odor and excellent image quality can be obtained.

The polymerization initiator may be added directly to the polymerizable monomer composition, and after the polymerizable monomer composition is dispersed in an aqueous dispersion medium containing a dispersion stabilizer, before droplet formation. It may be added at this stage.
The addition amount of the polymerization initiator is preferably 0.1 to 20 parts by mass, more preferably 0.3 to 15 parts by mass, and more preferably 1.0 to 10 parts by mass with respect to 100 parts by mass of the monovinyl monomer. More preferably, it is part by mass. If this amount is small, the fixability may be reduced, and conversely if it is large, the preservability may be reduced.

(A-3) Polymerization step A desired suspension (water system containing droplets of a polymerizable monomer composition) obtained by the step (A-2) of obtaining a suspension (droplet formation step). The dispersion medium) is heated to initiate polymerization, and an aqueous dispersion of colored resin particles is obtained.
The polymerization temperature in the present invention is preferably 50 ° C. or higher, more preferably 60 to 98 ° C. Further, the polymerization time in the present invention is preferably 1 to 20 hours, more preferably 2 to 15 hours.
In addition, in order to perform the polymerization in a state where the droplets of the polymerizable monomer composition are stably dispersed, the step (A-2) for obtaining the suspension (droplet formation step) also in this polymerization step. Subsequently, the polymerization reaction may be allowed to proceed while performing a dispersion treatment by stirring.

In the present invention, a colored resin particle obtained by the polymerization step is used as a core layer, and a so-called core-shell type (or “capsule type”) colored resin obtained by forming a shell layer different from the core layer on the outer side thereof. It is preferable to use particles.
The core-shell type colored resin particles provide a balance between lowering the fixing temperature of toner and preventing aggregation during storage by coating a core layer made of a material having a low softening point with a material having a higher softening point. Can be taken.

The method for producing the core-shell type colored resin particles is not particularly limited and can be produced by a conventionally known method. An in situ polymerization method and a phase separation method are preferable from the viewpoint of production efficiency.

A method for producing core-shell type colored resin particles by in situ polymerization will be described below.
By adding a polymerizable monomer (shell polymerizable monomer) for forming a shell layer and a shell polymerization initiator to an aqueous dispersion medium in which colored resin particles are dispersed, and performing polymerization. Core-shell type colored resin particles can be obtained.

As the polymerizable monomer for the shell, the same polymerizable monomers as those described above can be used. Among them, it is preferable to use monomers such as styrene and methyl methacrylate, which can produce a polymer having a Tg exceeding 80 ° C., alone or in combination of two or more.

Examples of the polymerization initiator for shell used for the polymerization of the polymerizable monomer for shell include potassium persulfate and persulfates such as ammonium persulfate; 2,2′-azobis (2-methyl-N- (2-hydroxyethyl) And water-soluble azo compounds such as 2,2′-azobis- (2-methyl-N- (1,1-bis (hydroxymethyl) 2-hydroxyethyl) propionamide)); An agent can be mentioned.
The addition amount of the polymerization initiator for shell used in the present invention is preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass with respect to 100 parts by mass of the polymerizable monomer for shell. preferable.

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

(A-4) Washing, filtration, dehydration, and drying steps The aqueous dispersion of colored resin particles obtained after the above (A-3) polymerization step is a series of operations of washing, filtration, dehydration, and drying in accordance with conventional methods. Is preferably repeated several times as necessary.

First, in order to remove the dispersion stabilizer remaining in the aqueous dispersion of colored resin particles, an acid or an alkali is added to the aqueous dispersion of colored resin particles and washed.
When the dispersion stabilizer used is an acid-soluble inorganic compound, an acid is added to the colored resin particle aqueous dispersion, while the dispersion stabilizer used is an alkali-soluble inorganic compound. In this case, an alkali is added to the colored resin particle aqueous dispersion.

When an acid-soluble inorganic compound is used as the dispersion stabilizer, it is preferable to adjust the pH to 6.5 or less by adding acid to the colored resin particle aqueous dispersion. More preferably, the pH is preferably adjusted to 6 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, but the removal efficiency of the dispersion stabilizer is large and the burden on the production equipment is small. Therefore, sulfuric acid is particularly preferable.

(B) Grinding method When the magenta colored resin particles are produced by employing the grinding method, the following process is performed.
First, a binder resin, a magenta pigment, a charge control agent, and other additives such as a release agent added as necessary are mixed in a mixer such as a ball mill, a V-type mixer, a Henschel mixer (trade name). ), Mix using a high-speed dissolver, internal mixer, Fallberg, etc. Next, the mixture obtained as described above is kneaded while being heated using a pressure kneader, a twin-screw extrusion kneader, a roller or the like. The obtained kneaded material is coarsely pulverized using a pulverizer such as a hammer mill, a cutter mill, or a roller mill. Furthermore, after finely pulverizing using a pulverizer such as a jet mill or a high-speed rotary pulverizer, it is classified into a desired particle size by a classifier such as an air classifier or an airflow classifier, and colored resin particles obtained by a pulverization method. Get.

In addition, other additives such as a binder resin, a magenta pigment, and a charge control agent used in the pulverization method, and a release agent added as necessary are those mentioned in the above (A) suspension polymerization method. Can be used. In addition, the magenta colored resin particles obtained by the pulverization method may be made into core-shell type colored resin particles by a method such as in situ polymerization method, similar to the magenta colored resin particles obtained by the suspension polymerization method (A) described above. it can.

As the binder resin, other resins that have been widely used for toners can be used. Specific examples of the binder resin used in the pulverization method include polystyrene, styrene-butyl acrylate copolymer, polyester resin, and epoxy resin.

2. Magenta colored resin particles Magenta colored resin particles can be obtained by the production method such as the above-described (A) suspension polymerization method or (B) pulverization method.
Hereinafter, the magenta colored resin particles constituting the toner (hereinafter sometimes simply referred to as colored resin particles) will be described. The magenta colored resin particles described below include both core-shell type and non-core type.

The volume average particle diameter Dv of the colored resin particles constituting the toner is preferably 4 to 12 μm, more preferably 5 to 11 μm, and even more preferably 6 to 10 μm from the viewpoint of image reproducibility. .
When the volume average particle diameter Dv of the colored resin particles is less than the above range, the fluidity of the toner is lowered, the image quality is liable to be deteriorated due to fogging, and the printing performance may be adversely affected. On the other hand, when the volume average particle diameter Dv of the colored resin particles exceeds the above range, the resolution of the obtained image tends to be lowered, and the printing performance may be adversely affected.

The particle size distribution Dv / Dn, which is the ratio of the volume average particle size Dv to the number average particle size Dn of the colored resin particles, is preferably 1.0 to 1.3 from the viewpoint of image reproducibility. 1.0 to 1.25 is more preferable, and 1.0 to 1.2 is more preferable.
When the particle size distribution Dv / Dn of the colored resin particles exceeds the above range, the fluidity of the toner is lowered, the image quality is liable to be deteriorated due to fogging, and the printing performance may be adversely affected.
The volume average particle diameter Dv and the number average particle diameter Dn of the colored resin particles are values measured using a particle size measuring machine.

Examples of the method for measuring the volume average particle diameter Dv and the method for calculating the particle diameter distribution Dv / Dn include the following methods. Note that the Dv measurement method and the Dv / Dn calculation method are not necessarily limited to the following methods.
First, about 0.1 g of colored resin particles are weighed, taken into a beaker, and 0.1 mL of an alkylbenzene sulfonic acid aqueous solution (manufactured by Fuji Film, trade name: Drywell) is added as a dispersant. Add 10-30 mL of Isoton II to the beaker and disperse with a 20 W (Watt) ultrasonic disperser for 3 minutes. Then, use a particle size analyzer (Beckman Coulter, trade name: Multisizer). , Aperture diameter: 100 μm, medium: Isoton II, number of measured particles: volume average particle diameter Dv and number average particle diameter Dn of the colored resin particles were measured under the conditions of 100,000 particles, and particle size distribution Dv / Dn Is calculated.

In the magenta toner of the present invention, the magenta colored resin particles can be used as the magenta toner as it is. However, from the viewpoint of adjusting the charging property, fluidity, storage stability and the like of the magenta toner, the magenta colored resin particles are used. In addition, the external additive may be mixed and stirred together with the external additive to perform the external addition process, thereby attaching the external additive to the surface of the magenta colored resin particles to form a one-component toner.
The one-component toner may be further mixed and stirred together with carrier particles to form a two-component developer.

The stirrer for performing the external addition treatment is not particularly limited as long as the stirrer can attach the external additive to the surface of the magenta colored resin particles. For example, an FM mixer (trade name, manufactured by Nippon Coke Kogyo Co., Ltd.), Super mixer (: trade name, manufactured by Kawada Seisakusho), Q mixer (: trade name, manufactured by Nihon Coke Kogyo Co., Ltd.), mechano-fusion system (: trade name, manufactured by Hosokawa Micron), and mechano mill (: trade name, Okada Seiko Co., Ltd.) The external addition treatment can be performed using a stirrer capable of mixing and stirring such as (made).

Examples of the external additive include inorganic fine particles composed of silica, titanium oxide, aluminum oxide, zinc oxide, tin oxide, calcium carbonate, calcium phosphate, and / or cerium oxide; polymethyl methacrylate resin, silicone resin, and / or melamine Organic fine particles made of a resin or the like; Among these, inorganic fine particles are preferable, and among inorganic fine particles, silica and / or titanium oxide are preferable, and fine particles made of silica are particularly preferable.
In addition, although these external additives can also be used individually, respectively, it is preferable to use 2 or more types together.

In the present invention, it is desirable to use the external additive at a ratio of usually 0.05 to 6 parts by mass, preferably 0.2 to 5 parts by mass with respect to 100 parts by mass of the magenta colored resin particles. If this amount is small, a transfer residue may occur, and if it is large, fogging may occur.

Hereinafter, specific embodiments of the present invention will be described in more detail by way of examples. However, the present invention is not limited to these examples unless it exceeds the gist. Parts and% are based on mass unless otherwise specified.

1. Production of magenta pigment composition <Magenta pigment composition (1)>
46 parts by mass of 3-amino-4-methoxybenzanilide was dispersed in 1000 parts by mass of water, and 35% -diluted hydrochloric acid (60 parts by mass) was added under a temperature condition of 5 ° C. or less, followed by stirring for 20 minutes. Thereafter, 50 parts by mass of a 30% -sodium nitrite aqueous solution was added and stirred for 60 minutes, and then 2 parts by mass of sulfamic acid was added to eliminate and decompose excess nitrous acid. Further, 50 parts by mass of sodium acetate and 75 parts by mass of 90% -acetic acid were added to prepare a diazonium salt aqueous solution.

Separately, 6 parts by mass of N- (3-nitrophenyl) -3-hydroxy-2-naphthalenecarboxamide and N- (5-chloro-2-methoxyphenyl) -3- After dissolving 51 parts by mass of hydroxy-2-naphthalenecarboxamide in 1000 parts by mass of water together with 25 parts by mass of sodium hydroxide, an aqueous calcium chloride solution and an anionic surfactant as a particle size adjusting agent for the pigment composition An appropriate amount of a certain alkylbenzenesulfonic acid was added to prepare a coupler aqueous solution.

Next, the diazonium salt aqueous solution is added to the coupler aqueous solution while stirring, and a coupling reaction is performed under the condition of pH 5.5 while maintaining a temperature of 20 ° C. or lower. Further, under a temperature condition of 90 ° C. or higher. A heat maturation treatment was performed to obtain a magenta crude pigment composition (1).

After the magenta crude pigment composition (1) was separated by filtration, the resulting pigment composition cake was redispersed in an aqueous sodium hydroxide solution and washed with alkali. After washing with alkali, the crude pigment composition (1) was again collected by filtration and thoroughly washed with water. After repeating this operation several times, it is dried at high temperature and pulverized. I. Pigment Red 31 (hereinafter sometimes referred to as P.R-31) and C.I. I. A magenta pigment composition (1) which is a solid solution containing CI Pigment Red 269 (hereinafter sometimes referred to as PR-269) at a mass ratio of 10:90 was obtained.

<Magenta pigment composition (2)>
The addition amount of 3-amino-4-methoxybenzanilide was changed to 47 parts by mass to prepare a diazonium salt aqueous solution, and the addition amount of N- (3-nitrophenyl) -3-hydroxy-2-naphthalenecarboxamide was changed to 17 Except that the aqueous coupler solution was prepared by changing the addition amount of N- (5-chloro-2-methoxyphenyl) -3-hydroxy-2-naphthalenecarboxamide to 40 parts by mass, the magenta pigment composition ( Prepared in the same manner as in 1). R-31 and P.I. A magenta pigment composition (2) which is a solid solution containing R-269 at a mass ratio of 30:70 was obtained.

<Magenta pigment composition (3)>
A diazonium salt aqueous solution was prepared by changing the addition amount of 3-amino-4-methoxybenzanilide to 51 parts by mass, and the addition amount of N- (3-nitrophenyl) -3-hydroxy-2-naphthalenecarboxamide was changed to 12 parts. Part by mass, the addition amount of N- (5-chloro-2-methoxyphenyl) -3-hydroxy-2-naphthalenecarboxamide was changed to 37 parts by mass, and further 12 parts by mass of 3-hydroxy-2-naphthalenecarboxamide In addition, except that a coupler aqueous solution was prepared, it was prepared in the same manner as the magenta pigment composition (1). R-31, P.I. R-269 and C.I. I. A magenta pigment composition (3), which is a solid solution containing CI Pigment Red 150 (hereinafter sometimes referred to as PR-150) at a mass ratio of 20:65:15, was obtained.

<Magenta pigment composition (4)>
A diazonium salt aqueous solution was prepared by changing the addition amount of 3-amino-4-methoxybenzanilide to 55 parts by mass, and N- (5-chloro-2-methoxyphenyl) -3-hydroxy-2-naphthalenecarboxamide The addition amount was changed to 23 parts by mass, and 26 parts by mass of 3-hydroxy-2-naphthalenecarboxamide was added instead of N- (3-nitrophenyl) -3-hydroxy-2-naphthalenecarboxamide to obtain an aqueous coupler solution. Except having been prepared, it was prepared in the same manner as the magenta pigment composition (1), and P.I. R-269 and P.I. A magenta pigment composition (4) which is a solid solution containing R-150 at a mass ratio of 40:60 was obtained.

<Magenta pigment composition (5)>
A diazonium salt aqueous solution was prepared by changing the addition amount of 3-amino-4-methoxybenzanilide to 55 parts by mass, and the addition amount of N- (3-nitrophenyl) -3-hydroxy-2-naphthalenecarboxamide was 25. In addition to 24 parts by mass of 3-hydroxy-2-naphthalenecarboxamide instead of N- (5-chloro-2-methoxyphenyl) -3-hydroxy-2-naphthalenecarboxamide, Except having been prepared, it was prepared in the same manner as the magenta pigment composition (1), and P.I. R-31 and P.I. A magenta pigment composition (5) which is a solid solution containing R-150 at a mass ratio of 45:55 was obtained.

2. Production of magenta toner <Example 1>
65 parts of styrene and 25 parts of butyl acrylate as a monovinyl monomer, 5 parts of the magenta pigment composition (1), and aluminum coupling agent (alkyl acetoacetate aluminum diisopropylate; manufactured by Ajinomoto Fine Techno Co., Ltd., trade name "AL-M") 0.2 part was added and stirred to prepare a polymerizable monomer mixture, which was subjected to dispersion treatment with a media type disperser to finely disperse the magenta pigment composition.

Next, 95.2 parts of a polymerizable monomer dispersion in which a magenta pigment composition is finely dispersed, 10 parts of styrene as a monovinyl monomer, a charge control agent (styrene / acrylic resin, manufactured by Fujikura Kasei Co., Ltd.) , Trade name "FCA-207P") 5 parts, dipentaerythritol hexamyristate 8 parts as a release agent, t-dodecyl mercaptan 1.2 parts as a molecular weight regulator, and divinylbenzene 0.4 parts as a crosslinkable monomer Part was added and dissolved by stirring to prepare a polymerizable monomer composition.

On the other hand, an aqueous solution obtained by dissolving 8.5 parts of magnesium chloride in 250 parts of ion-exchanged water and gradually adding an aqueous solution prepared by dissolving 6 parts of sodium hydroxide in 50 parts of ion-exchanged water was added to the magnesium hydroxide colloidal water system. A dispersion medium liquid was prepared.

The polymerizable monomer composition is added to the magnesium hydroxide colloidal aqueous dispersion medium obtained as described above, and after stirring, t-butylperoxy-2-ethylhexanoate (Nippon Yushi Co., Ltd.) is used as a polymerization initiator. (Product name: “Perbutyl O”) was further added, and using an in-line type emulsifying disperser, high shear stirring was performed under conditions of a peripheral speed of 40 m / s and a circulation number θ of 10 times, and the polymerization property was increased. A droplet of the monomer composition was formed.

The aqueous dispersion medium liquid in which droplets of the polymerizable monomer composition were dispersed was put into a reactor equipped with a stirring blade, and a polymerization reaction was started at 90 ° C. After the polymerization conversion reached almost 100%, the polymerization temperature was kept as it was, and 2,2′-azobis (2) dissolved in 2 parts of methyl methacrylate as a shell polymerizable monomer and 10 parts of ion-exchanged water. -Methyl-N- (2-hydroxyethyl) propionamide) (trade name “VA086” manufactured by Wako Pure Chemical Industries, Ltd.) was added in an amount of 0.1 part, and the reaction was continued at 90 ° C. for 3 hours. Then, an aqueous dispersion of magenta colored resin particles having a core-shell structure was obtained. The pH of the aqueous dispersion was 9.5.

While stirring the aqueous dispersion of magenta colored resin particles obtained above, the pH of the aqueous dispersion was adjusted to 6 or less with sulfuric acid, and water was separated by filtration. Thereafter, 500 parts of ion-exchanged water was newly added to reslurry, and the mixture was stirred for 10 minutes and washed with water. Filtration, dehydration, and water washing were repeated several times, and then the magenta colored resin particles were separated by filtration to obtain wet magenta colored resin particles. The wet magenta colored resin particles were vacuum dried at a temperature of 45 ° C. to obtain magenta colored resin particles.

In 100 parts of the magenta colored resin particles obtained as described above, 0.7 part of silica fine particles hydrophobized (manufactured by Cabot, product name “TG820F”) and silica fine particles hydrophobized (manufactured by Nippon Aerosil Co., Ltd., Product name: NEA50) 1.5 parts was added and mixed using an FM mixer to prepare a magenta toner of Example 1.

<Example 2>
A magenta toner of Example 2 was prepared in the same manner as in Example 1 except that the magenta pigment composition (1) was replaced with the magenta pigment composition (2).

<Example 3>
A magenta toner of Example 3 was prepared in the same manner as in Example 1 except that the magenta pigment composition (1) was replaced with the magenta pigment composition (3).

<Comparative Example 1>
A magenta toner of Comparative Example 1 was prepared in the same manner as in Example 1 except that the magenta pigment composition (1) was replaced with the magenta pigment composition (4).

<Comparative Example 2>
A magenta toner of Comparative Example 2 was prepared in the same manner as in Example 1 except that the magenta pigment composition (1) was replaced with the magenta pigment composition (5).

<Comparative Example 3>
A magenta pigment composition (1) was prepared from C.I. I. Pigment red 122 (1 part) and C.I. I. A magenta toner of Comparative Example 3 was prepared in the same manner as in Example 1 except that it was replaced with CI Pigment Red 150 (4 parts).

3. Evaluation of Magenta Toner Magenta toners of Examples 1 to 3 and Comparative Examples 1 to 3 were measured for toner characteristics and evaluated for printing. As the toner characteristics, the volume average particle diameter Dv was measured. As the printing evaluation, image density measurement, image light resistance evaluation, ejection evaluation after being left at high temperature, and printing durability evaluation under a high temperature and high humidity (H / H) environment were performed.

<1> Volume average particle diameter Dv measurement The volume average particle diameter Dv of magenta toner was measured by Multisizer (manufactured by Beckman Coulter, Inc.). The measurement with this multisizer was performed under the conditions of an aperture diameter: 100 μm, a medium: Isoton II, a concentration of 10%, and a measurement particle number: 100,000.

<2> Image Density Measurement A magenta toner is filled in a commercially available non-magnetic one-component developing type printer (HL-4040CN), and the amount of magenta toner on the transfer paper is 0.38 in an environment of a temperature of 23 ° C. and a humidity of 50%. A solid image was created at a density of 0.42 mg / cm ^{2 so} that the gloss of the image surface after heat and pressure fixation was 2-7, and the reflection density of the obtained image was measured with a spectrophotometer “Spectro Eye” (Gretag (Measured by Macbeth) and evaluated. The image density is preferably 1.20 or more.

<3> Image Light Resistance Evaluation A solid image in which the amount of magenta toner on the transfer paper is 0.38 to 0.42 mg / cm ^{2 in} a normal temperature and normal humidity (N / N) environment (temperature: 23 ° C., humidity: 50%). And an ultraviolet auto fade meter “FAL-AU” (manufactured by Suga Test Instruments Co., Ltd.) using a carbon arc lamp as a light source was evaluated according to “JIS K7102.” The exposure time was 120 hours, the image density maintenance ratio before and after the light irradiation was calculated, and the light resistance of the image was evaluated as follows. The closer the image density maintenance rate (%) is to 100%, the better the image light resistance, and B or higher is preferable.
A: 90% or more B: 80% or more, less than 90% C: 65% or more, less than 80% D: less than 65%

<4> Evaluation of ejection after standing at high temperature Using a commercially available non-magnetic one-component developing type printer (HL-4040CN), the toner cartridge of the developing device is filled with magenta toner, and then the toner cartridge is dried at 50 ° C. The cartridge was left in the machine for 120 hours, and the removed cartridge was set in a printer in a normal temperature and normal humidity (N / N) environment (temperature: 23 ° C., humidity: 50%) to perform continuous printing. Printing is performed at a halftone image density of 30%, and the number of spots of 0.3 × 0.3 mm or more on the halftone due to magenta toner ejected from the toner cartridge onto the printing paper is counted, and printing is performed until this number becomes zero. Went.
The evaluation is performed with the number of printed sheets until the number of spots on the printed material becomes zero, and the smaller number of printed sheets indicates that the printing can be performed without any image quality problem.

<5> Evaluation of printing durability under high temperature and high humidity (H / H) environment After standing in a high temperature and high humidity (H / H) environment (temperature: 28 ° C., humidity: 80%) for 24 hours, Then, continuous printing was performed up to 10,000 sheets at a 5% image density, and the number of continuously printed sheets capable of maintaining an image quality with a fog value of 1.3 or less was examined. The fog value is obtained by performing solid printing (image density 100%) and white solid printing (image density 0%) every 500 continuous prints, stopping the printer in the middle of white solid printing, The magenta toner in the non-image area was adhered to an adhesive tape (trade name: Scotch Mending Tape 810-3-18 manufactured by Sumitomo 3M Co.), and then peeled off and adhered to a printing paper. Next, the color tone (B) of the printing paper with the adhesive tape attached thereto was measured with the spectroeye. On the other hand, as a reference, the color tone (A) of a printing paper on which only an unused adhesive tape is attached is measured, and the obtained color tone (A) and color tone (B) are expressed as coordinates in the L * a * b * space. The color difference ΔE * was calculated as the fog value. Smaller values indicate less fog. In Table 1, “10,000 <” indicates that the image quality with a fog value of 1.3 or less was maintained even at the time of 10,000 sheets.

Table 1 shows the toner characteristics and print evaluation results of the magenta toners of Examples 1 to 3 and Comparative Examples 1 to 3. In Table 1 below, “PR-122” represents C.I. I. Pigment Red 122 is shown.

4). Summary of Evaluation of Magenta Toner First, the magenta toner of Comparative Example 1 is examined. The magenta toner of Comparative Example 1 had a good image density of 1.26, but the evaluation of image light resistance was C, the evaluation of jetting after standing at high temperature was 10, and high temperature and high humidity (H / H) ) Evaluation of printing durability under the environment was 9,000 sheets. Therefore, P.I. Does not include R-31, P.I. It contains only 40% by mass of R-269. The magenta toner of Comparative Example 1 containing 60% by mass of R-150 has low image light resistance, tends to be ejected after being left at high temperature, and has poor printing durability in a high temperature and high humidity (H / H) environment. I understand that.
Next, the magenta toner of Comparative Example 2 will be examined. The magenta toner of Comparative Example 2 had a good image density of 1.28, but the evaluation of image light resistance was D, the evaluation of ejection after standing at high temperature was 20, and high temperature and high humidity (H / H) ) Evaluation of printing durability under the environment was 8,000 sheets. Therefore, P.I. R-269 is not included, and P.I. Including 45% by mass of R-31; The magenta toner of Comparative Example 2 containing 55% by mass of R-150 has a lower image light resistance than the toner of Comparative Example 1, and is more likely to erupt after being left at a high temperature. H) It can be seen that the printing durability under the environment is even worse.
Subsequently, the magenta toner of Comparative Example 3 will be examined. The magenta toner of Comparative Example 3 had an image light fastness evaluation of A, but the image density was as low as 1.09, evaluation of ejection after standing at high temperature was 20 sheets, high temperature and high humidity (H / H) environment The print durability evaluation below was 8,000 sheets. Therefore, P.I. R-31 and P.I. R-269 is not included. P.S., which contains 80% by mass of R-150, and is a kind of quinacridone magenta colorant. The magenta toner of Comparative Example 3 containing 20% by mass of R-122 has a remarkably low image density. Further, the magenta toner of the comparative example 3 is more likely to be ejected after being left at a high temperature than the toner of Comparative Example 1, and has a high temperature and high humidity (H / H). H) It can be seen that the printing durability under the environment is even worse.
In contrast to the magenta toners of Comparative Examples 1 to 3, all of the magenta toners of Examples 1 to 3 have an image density of 1.22 or more, an evaluation of image light resistance of A, and an evaluation of ejection after being left at high temperature of 0. Evaluation of printing durability under high-temperature and high-humidity (H / H) environment was more than 10,000 sheets. Therefore, the magenta toners of Examples 1 to 3 are toners that achieve both high light resistance and high image density, and do not erupt after being allowed to stand at high temperature, and in a high temperature and high humidity (H / H) environment. It can be seen that the durability performance is high.

Claims

A magenta toner containing magenta colored resin particles containing a binder resin and a magenta pigment,
As the magenta pigment, C.I. I. Pigment red 31 and C.I. I. A magenta toner comprising Pigment Red 269.
When the total content of the magenta pigment is 100% by mass, the C.I. I. Pigment Red 31 is contained in an amount of 5 to 40% by mass, and C.I. I. The magenta toner according to claim 1, wherein the content ratio of Pigment Red 269 is 60 to 95% by mass.
As the magenta pigment, C.I. I. Pigment Red 150, and
When the total content of the magenta pigment is 100% by mass, the C.I. I. 3. The magenta toner according to claim 1, wherein the content ratio of Pigment Red 150 is 35% by mass or less.
The magenta toner according to any one of claims 1 to 3, wherein the magenta pigment is a solid solution pigment.
The magenta toner according to any one of claims 1 to 4, comprising 100 parts by mass of the binder resin and 1 to 10 parts by mass of the magenta pigment.
The magenta toner according to any one of claims 1 to 5, wherein the magenta colored resin particles further contain a charge control resin.
The magenta toner according to any one of claims 1 to 6, wherein the magenta colored resin particles have a core-shell structure.