JP2009086331A - Green toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a green toner, which is excellent in reproducibility of green color, has excellent thin line reproducibility of print even in continuous printing of many sheets, hardly causes deterioration of image quality by fogging or the like even in a high-temperature and high-humidity environment, and has excellent printing performance such as print durability. <P>SOLUTION: The green toner comprises colored resin particles produced by suspending and polymerizing a polymerizable monomer composition including at least a polymerizable monomer and a coloring agent in an aqueous dispersion medium containing a dispersion stabilizing agent. The coloring agent includes a cyan coloring and a yellow coloring agent. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a green toner (hereinafter sometimes simply referred to as “toner”) used for developing an electrostatic latent image in electrophotography, electrostatic recording, electrostatic printing, and the like. Specifically, the present invention relates to a green toner that has excellent green reproducibility and excellent printing performance.

  In recent years, there is an increasing need for color printing for image forming apparatuses such as copying machines, facsimiles, and printers using electrophotography. In color printing, reproducibility of a clear color tone is required, and a color toner that can cope with printing of high-definition images such as photographs is required.

  In general, an image forming apparatus capable of supporting color printing is a total of three primary colors, cyan (blue), magenta (red), and yellow (yellow), and black (black) toner. Four color toners are installed. For example, when printing a green image, the color tone is reproduced by superimposing (mixing colors) blue and yellow toners on the printing paper.

In addition to printing by mixing blue and yellow toners on the surface of the printing paper as described above, printing can also be performed using a single color green toner alone.
The above-mentioned method for obtaining a monochromatic green toner includes (1) the production of a green toner using one kind of green pigment as a colorant, and (2) the use of a mixture of two kinds of a blue pigment and a yellow pigment as a colorant. In the case of producing green toner, it is roughly classified, and development is proceeding in each case.

  (1) In the case of producing a green toner using one kind of green pigment as a colorant, C.I. I. Green toners have been manufactured using typical green pigments such as Pigment Green 7, 36. However, although the green pigment exhibits a relatively good green color, it contains an electron-withdrawing halogen atom in its chemical structure, so it tends to cause poor charging and is used for environmental considerations. It has been pointed out that there are problems.

  Patent Document 1 discloses a green toner produced by an emulsion polymerization aggregation method (EA method) using a copper tetra- (α-hydroxyethoxy) phthalocyanine pigment not containing a halogen atom. However, the evaluation test performed in Patent Document 1 does not evaluate the printed image using the green toner alone, and the green reproducibility due to the use of the copper tetra- (α-hydroxyethoxy) phthalocyanine pigment. The effect is not certain.

  (2) Various studies have also been made in the case of producing a green toner using a mixture of two types of blue and yellow pigments as colorants.

  In Patent Document 2, a positively chargeable green toner containing a binder resin, a yellow colorant, and a blue colorant, wherein the yellow colorant is a monoazo pigment, disazo pigment, isoindolinone pigment, isoindoline. And at least one pigment selected from benzimidazolone pigments, the blue colorant is a phthalocyanine pigment, and both the yellow colorant and the blue colorant are pigments that do not contain a halogen atom. A positively charged green toner is disclosed.

  In Patent Document 3, in an electrostatic image developing green toner comprising at least a binder resin and a colorant, the binder resin is a specific non-linear polyester resin, and the colorant is a phthalocyanine containing no halogen. There is disclosed a green toner for developing an electrostatic image, which is a colorant obtained by mixing a blue blue pigment and a benzimidazolone yellow pigment containing no halogen at a specific blending ratio.

However, although the green toner disclosed in Patent Documents 2 and 3 is considered to have a relatively good green reproducibility, it is a toner manufactured by a pulverization method, and thus has a small particle size and a spherical shape. Therefore, it can be said that the toner does not reach the high required level for obtaining high-quality images in recent years.
For this reason, further examination is required to obtain a green toner having both green reproducibility and high printing performance.

JP 2005-157314 A JP 2003-280275 A JP 2005-208362 A

  The object of the present invention is excellent in green reproducibility, has excellent fine line reproducibility even when continuous printing of a large number of sheets, and deteriorates image quality due to fog or the like even in a high temperature and high humidity environment. It is an object of the present invention to provide a green toner that is less likely to occur and has excellent printing performance such as printing durability.

  The present inventors diligently studied to achieve the above object, and as a coloring agent, a cyan coloring agent and a yellow coloring agent are mixed and used, and suspension polymerization is performed to produce colored resin particles. The inventors have found that a green toner having excellent reproducibility and excellent printing performance can be obtained, and based on these findings, the present invention has been completed.

That is, the green toner of the present invention is a color produced by suspension polymerization of a polymerizable monomer composition comprising at least a polymerizable monomer and a colorant in an aqueous dispersion medium containing a dispersion stabilizer. In green toner containing resin particles,
The green toner is characterized in that the colorant is a cyan colorant and a yellow colorant.

  According to the green toner of the present invention as described above, the green reproducibility is excellent, even when continuous printing of a large number of sheets is performed, the fine line reproducibility of the print is excellent, and even in a high temperature and high humidity environment, Provided is a green toner that is unlikely to deteriorate in image quality due to fog or the like and that has excellent printing performance such as printing durability.

The green toner of the present invention is a colored resin produced by suspension polymerization of a polymerizable monomer composition comprising at least a polymerizable monomer and a colorant in an aqueous dispersion medium containing a dispersion stabilizer. In green toner containing particles,
The colorant is a cyan colorant and a yellow colorant.

  Hereinafter, a process for obtaining the green toner of the present invention will be described.

(1) Preparation Step of Polymerizable Monomer Composition First, a polymerizable monomer, a cyan colorant, and a yellow colorant are mixed with other additives such as a surface treatment agent and a charge control agent as necessary. The polymerizable monomer composition is prepared by dissolving. In addition, mixing at the time of preparing a polymerizable monomer composition is performed using a media-type disperser, for example.

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 weight, preferably 0.3 to 2 parts by weight, with respect to 100 parts by weight 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 is 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.

In the present invention, a cyan colorant and a yellow colorant are mixed and used as the colorant.
The cyan colorant used in the present invention is not particularly limited as long as it is generally used as a cyan colorant for toner, but fluorine, chlorine, bromine, iodine, etc. are used in the chemical structure. A pigment containing no halogen atom is preferably used.
Examples of cyan colorants include C.I. I. Pigment Blue 15, 15: 2, 15: 3, 16, and 17, and the like.
These cyan colorants can be used alone or in combination of two or more.

The yellow colorant used in the present invention can be used without particular limitation as long as it is generally used as a yellow colorant for toner, but fluorine, chlorine, bromine, iodine, etc. in the chemical structure. A pigment containing no halogen atom is preferably used.
Examples of the yellow colorant include C.I. I. Pigment Yellow 151, 155, 175, 180, 185, and 213.
These yellow colorants can be used alone or in combination of two or more.

  In the present invention, the types of “cyan colorant” and “yellow colorant” selected for developing green are “CI Pigment Blue 15: 3” from the viewpoint of excellent green reproducibility. It is preferable to use a combination of “CI Pigment Yellow 175” or a combination of “CI Pigment Blue 15: 3” and “CI Pigment Yellow 213”.

  In the present invention, in order to obtain a green toner, the blending ratio (B) :( Y) of the cyan colorant (B) and the yellow colorant (Y) used by mixing is usually from 80:20 to weight ratio. 20:80, preferably 70:30 to 30:70, more preferably 60:40 to 40:60.

  In the present invention, in order to obtain a green toner, the total amount of the colorant used by mixing the cyan colorant and the yellow colorant is 1 to 30 parts by weight with respect to 100 parts by weight of the monovinyl monomer. Preferably, it is 2 to 20 parts by weight, more preferably 4 to 15 parts by weight.

In the present invention, the colorant is preferably used after being surface-treated with a surface treatment agent in order to improve the dispersibility and coloring power of the colorant.
In the surface treatment, a colorant that has been previously surface-treated by mixing a cyan colorant and a yellow colorant together with the surface treatment agent may be used in the preparation step of the polymerizable monomer composition. In the preparation step of the monomer composition, the surface treatment agent may be directly contained in the polymerizable monomer composition and mixed to perform the surface treatment.

The surface treatment agent used in the present invention is not particularly limited as long as it is generally used for toners for the purpose of improving the dispersibility and coloring power of the colorant.
Typical examples of the surface treatment agent include titanate coupling agents, aluminum coupling agents, and silane coupling agents. Among these, a titanate coupling agent and an aluminum coupling agent are preferably used because the effect of improving the dispersibility and coloring power of the colorant is high.

As the surface treating agent used in the present invention, various commercially available products can be used.
Commercially available titanate coupling agents include, for example, Ajinomoto Finetechno's Plenact series, KR 44 (: trade name), KR 38S (: trade name), KR TTS (: trade name), KR 46B (: Product Name), KR 55 (: Product Name), KR 41B (: Product Name), KR 38S (: Product Name), KR 138S (: Product Name), KR 238S (: Product Name), and 338X (: Product Name) ), KR 9SA (: trade name) and the like.
As a commercial item of an aluminum coupling agent, AL-M (: brand name) etc. are mentioned, for example in the Ajinomoto fine techno pre-act series.

  The addition amount of the surface treating agent used in the present invention is preferably 0.1 to 20 parts by weight with respect to 100 parts by weight of the monovinyl monomer and 100 parts by weight of the monovinyl monomer. More preferably, it is -15 weight part, and it is further more preferable that it is 1-8 weight part.

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 wax such as paraffin, microcrystalline and petrolatum; mineral wax such as montan, ceresin and ozokerite; synthetic wax 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 this invention, it is desirable to use a mold release agent in the ratio of 0.1-30 weight part normally with respect to 100 weight part of monovinyl monomers, Preferably it is 1-20 weight part.

As other additives, various charge control agents having positive chargeability or negative chargeability can be used in order 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. In the present invention, the charge control agent is highly compatible with the polymerizable monomer and has stable chargeability ( Since charge stability can be imparted to the toner particles, it is preferable to use a charge control resin.
For example, various commercially available products can be used as the positively chargeable charge control resin, and those manufactured by Fujikura Kasei Co., Ltd. include FCA-161P (trade name, styrene / acrylic resin), FCA-207P (trade name). , Styrene / acrylic resin), FCA-201-PS (: trade name, styrene / acrylic resin), and the like.
In the present invention, it is desirable to use the charge control agent in a proportion of usually 0.01 to 10 parts by weight, preferably 0.03 to 8 parts by weight, with respect to 100 parts by weight of the monovinyl monomer.

It is preferable to use a molecular weight modifier as another additive.
The molecular weight modifier is not particularly limited as long as it is generally used as a molecular weight modifier for toner. 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 and 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 modifier in a proportion of usually 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, with respect to 100 parts by weight of the monovinyl monomer.

(2) Suspension step for obtaining a suspension (droplet formation step)
(1) The polymerizable monomer composition obtained through the preparation process of the polymerizable monomer composition is suspended in an aqueous dispersion medium and suspended (polymerizable monomer composition dispersion). Get. 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 emulsifier / disperser (manufactured by Tokushu Kika Kogyo Co., Ltd., trade name: TK). Etc. can be carried out using a device capable of strong stirring, such as a homomixer MARK II).

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 amount of the dispersion stabilizer added is preferably 0.1 to 20 parts by weight and more preferably 0.2 to 10 parts by weight with respect to 100 parts by weight of the polymerizable monomer.

  Examples of the polymerization initiator used for polymerization of the polymerizable monomer composition include inorganic 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 azo compounds such as 2,2′-azobisisobutyronitrile; di-t-butyl peroxide, benzoyl peroxide, t-butylperoxy-2-ethylhexanoate, t-hexylperoxy- 2-ethylhexanoate, t-butyl peroxypivalate, diisopropyl peroxydicarbonate, di-t-butyl peroxyiso Tallates, and t- butylperoxy isobutyrate and the like organic peroxides;., Etc. Among these, organic peroxides are preferably used.

The polymerization initiator may be added at the stage before the droplet formation after the polymerizable monomer composition is dispersed in the aqueous dispersion medium containing the dispersion stabilizer. It may be added directly to the composition.
The addition amount of the polymerization initiator is preferably 0.1 to 20 parts by weight, more preferably 0.3 to 15 parts by weight with respect to 100 parts by weight of the monovinyl monomer, and 1.0 to 10 parts by weight. More preferably, it is part by weight.

(3) Suspension polymerization step (2) Aqueous dispersion medium containing droplets of a polymerizable monomer composition obtained by the step (2) step of obtaining a suspension (droplet formation step) ) 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, and more preferably 60 to 98 ° C. Further, the polymerization time in the present invention is preferably 1 to 20 hours, and 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, also in the suspension polymerization step (2) in the step of obtaining the suspension (droplet formation step). Subsequently, the suspension polymerization reaction may be allowed to proceed while performing a dispersion process by stirring.

In the present invention, the colored resin particles obtained by the suspension polymerization process are used as a core layer, and a shell layer different from the core layer is formed on the outer side thereof, so-called core-shell type (also referred to as “capsule type”). It is preferable to use colored resin 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.

  There is no restriction | limiting in particular as a method of manufacturing the said core-shell type colored resin particle, It can manufacture by a conventionally well-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 for forming a shell layer (polymerizable monomer for shell) and a polymerization initiator for shell into 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 monomer as 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 shell polymerization initiator used for the polymerization of the shell polymerizable monomer include potassium persulfate and persulfate metal salts such as ammonium persulfate; 2,2′-azobis (2-methyl-N- (2-hydroxy Water-soluble azo compounds such as ethyl) propionamide) and 2,2′-azobis- (2-methyl-N- (1,1-bis (hydroxymethyl) 2-hydroxyethyl) propionamide); Mention may be made of initiators.
The addition amount of the polymerization initiator for shell used in the present invention is preferably 0.1 to 30 parts by weight, more preferably 1 to 20 parts by weight with respect to 100 parts by weight of the polymerizable monomer for shell. preferable.

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

(4) Washing, filtration, dehydration, and drying step The aqueous dispersion of colored resin particles obtained in the above (3) suspension polymerization step requires a series of operations of washing, filtration, and dehydration according to conventional methods. Depending on the process, the process is repeated several times, and the obtained solid content is dried according to a conventional method to obtain colored resin particles.

First, in order to remove the dispersion stabilizer remaining in the aqueous dispersion of colored resin particles, washing is performed by adding an acid or an alkali to the aqueous dispersion of colored resin particles.
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 add an acid to the aqueous dispersion of colored resin particles and perform acid washing until the pH is 6.5 or lower. As the acid added in the acid washing, inorganic acids such as sulfuric acid, hydrochloric acid, and nitric acid; organic acids such as formic acid and acetic acid; and the like can be used. Among these, sulfuric acid is particularly preferable because the removal efficiency of the dispersion stabilizer is good and the burden on the toner production facility is small.

(5) Colored resin particles Hereinafter, the colored resin particles constituting the toner will be described. The 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 5 to 10 μm and more preferably 6 to 9 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 1.0 to 1. 4, more preferably 1.0 to 1.3, and even more preferably 1.0 to 1.2.
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. is there.
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.

The average circularity of the colored resin particles is preferably 0.97 or more, and more preferably 0.975 or more, from the viewpoint of image reproducibility.
When the average circularity of the colored resin particles is less than the above range, the fine line reproducibility of printing tends to be lowered, and the printing performance may be adversely affected.

In the present invention, “circularity” is defined as a value obtained by dividing the circumference of a circle having the same projected area as the particle image by the circumference of the projected image of the particle. The average circularity in the present invention is used as a simple method for quantitatively expressing the shape of the particles, and is an index indicating the degree of unevenness of the colored resin particles. The average circularity is determined by the colored resin particles. 1 is shown in the case of a perfect sphere, and the value becomes smaller as the surface shape of the colored resin particles becomes more complicated. For the average circularity, the circularity (Ci) of each particle measured for a particle group having an equivalent circle diameter of 0.6 μm or more was determined for each of n particles from the following calculation formula 1, and then averaged from the following calculation formula 2. Obtain the circularity (Ca).
Formula 1:
Circularity (Ci) = perimeter of circle equal to projected area of particle / perimeter of projected particle image

In the above calculation formula 2, fi is the frequency of particles having a circularity (Ci).
The circularity can be measured using a flow type particle image analyzer “FPIA-2000”, “FPIA-2100”, “FPIA-3000”, etc. manufactured by Sysmex Corporation.

(6) Green toner The colored resin particles obtained in the present invention may be used as they are or with colored resin particles and carrier particles (ferrite, iron powder, etc.). From the viewpoint of adjusting storability and the like, a high-speed stirrer (for example, trade name: Henschel mixer (manufactured by Mitsui Mining Co., Ltd.)) may be used to mix colored resin particles with external additives to form a one-component toner The two-component developer may be obtained by mixing the colored resin particles with an external additive and further carrier particles.

External additives include inorganic fine particles composed of silica, titanium oxide, aluminum oxide, zinc oxide, tin oxide, calcium carbonate, calcium phosphate, cerium oxide, etc .; polymethyl methacrylate resin, silicone resin, melamine resin, etc. Organic fine particles; and the like. Among these, inorganic fine particles are preferable, and among inorganic fine particles, silica and titanium oxide are preferable, and silica is particularly preferable. The above external additives can be used alone, but it is preferable to use two or more kinds in combination.
In the present invention, it is desirable to use the external additive in a proportion of usually 0.1 to 6 parts by weight, preferably 0.2 to 5 parts by weight with respect to 100 parts by weight of the colored resin particles.

  The green toner produced through the steps (1) to (6) is a mixture of a cyan colorant and a yellow colorant as a colorant, and suspension polymerization is performed to produce colored resin particles. Excellent green reproducibility, excellent thin line reproducibility even when continuous printing of many sheets is performed, and even under high-temperature and high-humidity environments, image quality deterioration due to fog and the like hardly occurs, and printing durability Green toner with excellent printing performance.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited only to these examples. Parts and% are based on weight unless otherwise specified.
The test methods performed in the examples and comparative examples are as follows.

(1) Colored resin particles (1-1) Volume average particle diameter Dv and particle diameter distribution Dv / Dn
About 0.1 g of a measurement sample (colored resin particles) was weighed and taken in a beaker, and 0.1 ml of an alkylbenzene sulfonic acid aqueous solution (manufactured by Fuji Film Co., Ltd., trade name: Drywell) was added as a dispersant. 10-30 ml of Isoton II is further added to the beaker and dispersed for 3 minutes with a 20 W ultrasonic disperser. The volume average particle diameter (Dv) and the number average particle diameter (Dn) of the colored resin particles were measured under the conditions of 100 μm, medium; Isoton II, number of measured particles; 100,000 particles, and the particle size distribution (Dv / Dn) was calculated.

(1-2) Average circularity Into a container, 10 ml of ion-exchanged water is put in advance, 0.02 g of a surfactant (alkylbenzenesulfonic acid) is added as a dispersant, and a measurement sample (colored resin particles) 0. 02 g was added, and the dispersion treatment was performed at 60 W for 3 minutes using an ultrasonic disperser. The concentration of the colored resin particles at the time of measurement is adjusted to 3,000 to 10,000 particles / μl, and flow type particle images of 1,000 to 10,000 colored resin particles having an equivalent circle diameter of 0.4 μm or more are used. It measured using the analyzer (Simex company make, brand name: FPIA-2100). The average circularity was determined from the measured value.
The circularity is shown in the following calculation formula 1, and the average circularity is an average of the circularity.
Formula 1:
(Circularity) = (Perimeter of circle equal to projected area of particle) / (Perimeter of particle projection image)

(2) Printing test (2-1) Initial printing density (under N / N environment)
In the evaluation of the printing durability test under the N / N environment described later, green solid printing (printing density 100%) is performed on the fifth sheet, and a reflection type image densitometer (trade name: RD918, manufactured by Macbeth Co., Ltd.) is used. Then, the initial print density of the green solid image was measured.

(2-2) Fine line reproducibility (under N / N environment)
For the fine line reproducibility test, a commercially available non-magnetic one-component development type printer (printing speed: A4 size 20 sheets / min) was used, and the toner cartridge of the developing device was filled with green toner, and then printing paper was set. .
After standing for 24 hours in a normal temperature and normal humidity (N / N) environment (temperature: 23 ° C., humidity: 50%), 2 × 2 dot lines (width: about 85 μm) continuously in the same environment Images were formed and continuous printing was performed up to 10,000 sheets.
For every 500 sheets, density distribution data of line images was collected using a printing evaluation system (trade name: RT2000, manufactured by YA-MA).
Based on the density distribution data of the collected line image, the line width is determined based on the line width formed on the first sheet of print paper, with the full width of the line image at the half value of the maximum density as the line width. The number of continuously printed sheets that can maintain the difference of 10 μm or less was examined.
In Table 1, “10,000 <” indicates that the line width difference could be maintained at 10 μm or less even at the time of 10,000 sheets.

(2-3) Printing durability (N / N environment, H / H environment)
For the printing durability test, a commercially available non-magnetic one-component developing type printer (printing speed: A4 size 20 sheets / min) was used, and the toner cartridge was filled in the toner cartridge of the developing device, and then the printing paper was set. .
After standing for 24 hours in a normal temperature and normal humidity (N / N) environment (temperature: 23 ° C., humidity: 50%), continuous printing was performed up to 10,000 sheets at a 5% print density in the same environment. .
Every 500 sheets, green solid printing (printing density 100%) was performed, and the printing density of the green solid image was measured using a reflective image densitometer (manufactured by Macbeth, trade name: RD918). After that, white solid printing (printing density 0%) is performed, the printer is stopped in the middle of white solid printing, and the toner in the non-image area on the developed photoreceptor is covered with an adhesive tape (manufactured by Sumitomo 3M Limited, product Name: Scotch mending tape 810-3-18), and then peeled off and affixed to printing paper. Next, the whiteness (B) of the printing paper on which the adhesive tape is affixed is measured with a whiteness meter (trade name: ND-1 manufactured by Nippon Denshoku Co., Ltd.). The whiteness (A) was measured and the difference in whiteness (B−A) was defined as the fog value (%). Smaller values indicate better fog and better.
The number of continuously printed sheets that can maintain an image quality with a print density of 1.3% or more and a fog value of 3% or less was examined.
The same printing durability test was also performed in a high temperature and high humidity (H / H) environment (temperature: 35 ° C., humidity: 80%).
In Table 1, “10,000 <” means that the image density of 1.3% or more and the fog value of 3% or less could be maintained even when 10,000 sheets were printed. Indicates.

Example 1
80 parts of styrene and 20 parts of n-butyl acrylate as a monovinyl monomer and C.I. I. Pigment Blue 15: 3 (manufactured by Clariant, trade name: Hostaperm Blue B4G), 2 parts C.I. I. 2 parts of Pigment Yellow 175 (manufactured by Clariant, trade name: Permanent Yellow GRX83), 1 part of titanate coupling agent (manufactured by Ajinomoto Fine Techno Co., trade name: KR 44) as a surface treatment agent, positive charge as a charge control agent 1 part of a control resin (manufactured by Fujikura Kasei Co., Ltd., trade name: FCA-207P, styrene / acrylic resin), 0.6 part of divinylbenzene as a crosslinkable polymerizable monomer, 0.8 part of t-dodecyl mercaptan as a molecular weight regulator Parts, and 0.5 parts of polymethacrylate macromonomer (manufactured by Toa Gosei Co., Ltd., trade name: AA6, Tg = 94 ° C. of the resulting polymer) as a macromonomer, and after stirring and mixing with a stirrer, further media It was uniformly dispersed using a type disperser. Here, 6 parts of dipentaerythritol hexamyristate was added, mixed and dissolved as a release agent to obtain a polymerizable monomer composition.

  On the other hand, at room temperature, in an aqueous solution in which 10.2 parts of magnesium chloride (water-soluble polyvalent metal salt) is dissolved in 250 parts of ion-exchanged water, sodium hydroxide (alkali metal hydroxide) 6.2 in 50 parts of ion-exchanged water. The aqueous solution in which the part was dissolved was gradually added with stirring to prepare a magnesium hydroxide colloid (slightly water-soluble metal hydroxide colloid) dispersion.

  The polymerizable monomer composition was charged into the magnesium hydroxide colloid dispersion at room temperature and stirred. After adding 6 parts of t-butyl peroxy-2-ethylhexanoate (Nippon Yushi Co., Ltd., trade name: Perbutyl O) as a polymerization initiator, an in-line type emulsifier / disperser (trade name, manufactured by Ebara Corporation) is added. : Ebara Milder) was dispersed by high-speed shearing and stirring for 10 minutes at a rotational speed of 15,000 rpm to form droplets of the polymerizable monomer composition.

  A suspension (polymerizable monomer composition dispersion) in which droplets of the polymerizable monomer composition are dispersed is placed in a reactor equipped with a stirring blade, heated to 90 ° C., and polymerized. The reaction was started. When the polymerization conversion reached almost 100%, 2,2′-azobis (shell polymerization initiator dissolved in 1 part of methyl methacrylate and 10 parts of ion-exchanged water as shell polymerizable monomer) 0.3 part of 2-methyl-N- (2-hydroxyethyl) -propionamide) (manufactured by Wako Pure Chemical Industries, Ltd., trade name: VA-086, water-soluble) was added, and the reaction was continued at 90 ° C. for 4 hours. Thereafter, the reaction was stopped by cooling with water to obtain an aqueous dispersion of colored resin particles having a core-shell structure.

The aqueous dispersion of the colored resin particles was dropped at room temperature while stirring sulfuric acid, and acid washing was performed until the pH became 6.5 or lower. Subsequently, filtration separation was performed, 500 parts of ion-exchanged water was added to the obtained solid content to make a slurry again, and water washing treatment (washing, filtration, dehydration) was repeated several times. Subsequently, filtration separation was performed, and the obtained solid content was put in a container of a dryer and dried at 45 ° C. for 48 hours to obtain dried colored resin particles.
The colored resin particles obtained by drying had a volume average particle size (Dv) of 7.8 μm, a particle size distribution (Dv / Dn) of 1.18, and an average circularity of 0.978.

  To 100 parts of the colored resin particles obtained as described above, 0.8 parts of silica fine particles having a number average primary particle diameter of 7 nm (product name: TG820F, manufactured by Cabot Corporation) and silica fine particles having a number average primary particle diameter of 35 nm (Nippon Aerosil Co., Ltd.) 1 part of the product, product name: NA50Y) was added, and the mixture was stirred and externally added using a high-speed stirrer (trade name: Henschel mixer, manufactured by Mitsui Mining Co., Ltd.) to produce the green toner of Example 1. The test was conducted.

(Example 2)
In Example 1, the type of yellow colorant is C.I. I. A green toner of Example 2 was produced in the same manner as in Example 1 except that it was changed to Pigment Yellow 213 (trade name: Hostaper Yellow H5G, manufactured by Clariant) and used for the test.

(Example 3)
In Example 1, the type of the cyan colorant is C.I. I. Pigment Blue 16 (manufactured by BASF, trade name: Heliogen Blue D 7490), and the surface treatment agent was changed to an aluminum coupling agent (manufactured by Ajinomoto Fine Techno Co., trade name: AL-M). The green toner of Example 2 was produced in the same manner as Example 1 and used for the test.

Example 4
In Example 1, the type of the cyan colorant is C.I. I. Pigment Blue 16 (trade name: Helogen Blue D 7490, manufactured by BASF), and the type of yellow colorant is C.I. I. A green toner of Example 4 was produced in the same manner as in Example 1 except that it was changed to Pigment Yellow 185 (trade name: Paliotol Yellow D1155, manufactured by BASF Corporation), and used for the test.

(Example 5)
In Example 1, the type of the cyan colorant is C.I. I. Pigment Blue 16 (trade name: Helogen Blue D 7490, manufactured by BASF), and the type of yellow colorant is C.I. I. A green toner of Example 5 was produced in the same manner as in Example 1 except that it was changed to Pigment Yellow 180 (trade name: Fsat Yellow HG, manufactured by Clariant), and used for the test.

(Example 6)
In Example 1, the type of the cyan colorant is C.I. I. Pigment Blue 16 (trade name: Helogen Blue D 7490, manufactured by BASF), and the type of yellow colorant is C.I. I. A green toner of Example 6 was produced in the same manner as in Example 1 except that it was changed to Pigment Yellow 155 (manufactured by Clariant, trade name: Toner Yellow 3GP).

(Example 7)
In Example 1, the type of the cyan colorant is C.I. I. Pigment Blue 16 (trade name: Helogen Blue D 7490, manufactured by BASF), and the type of yellow colorant is C.I. I. A green toner of Example 7 was produced in the same manner as in Example 1 except that it was changed to Pigment Yellow 151 (trade name: H4GN, manufactured by Clariant), and used for the test.

(Comparative Example 1)
86 parts of SBM-600 (trade name, manufactured by Sanyo Kasei Co., Ltd., styrene-acrylic copolymer resin) as a binder resin and C.I. I. Pigment Blue 15: 3 (manufactured by Clariant, trade name: Hostaperm Blue B4G), 2 parts C.I. I. Pigment Yellow 180 (manufactured by Clariant, trade name: Fsat Yellow HG), 2 parts of Hymer 550P as a release agent (trade name, manufactured by Sanyo Kasei, polypropylene wax), and triphenylmethane derivative as a charge control agent 1 part (manufactured by Clariant, trade name: Copy Blue ER) was kneaded at about 130 ° C. for 20 minutes using a kneader (pressure kneader), cooled, then coarsely crushed with a hammer mill, Then, it was finely pulverized and classified with an I-type jet mill DR classifier (manufactured by NPK) until the average particle diameter became 7.8 μm, and a green toner of Comparative Example 1 was produced and used for the test.

(Comparative Example 2)
The type of yellow colorant is C.I. I. A green toner of Comparative Example 2 was produced in the same manner as Comparative Example 1 except that it was changed to Pigment Yellow 151 (trade name: H4GN, manufactured by Clariant), and used for the test.

(result)
Table 1 shows the test results of the green toner prepared in each example and comparative example.
The notes in Table 1 are as follows.
* 1: Titanate (titanate coupling agent), aluminum (aluminum coupling agent)
* 2: CCR (charge control resin), CCA (charge control agent)

(Summary of results)
From the test results described in Table 1, the following can be understood.
The green toners of Comparative Examples 1 and 2 are green toners that have poor green reproducibility and inferior printing performance due to the fact that they were manufactured by a pulverization method without using a surface treatment agent and a charge control resin. It was.

In contrast, the green toners of Examples 1 to 7 are produced by suspension polymerization using a mixture of a cyan colorant and a yellow colorant as a colorant, and also using a surface treatment agent and a charge control resin. As a result, the dispersibility and coloring power of the colorant can be improved, and stable chargeability can be imparted to the toner particles, so that the green reproducibility is excellent and the printing performance is also excellent. Green toner.
Among these, in the green toners of Examples 1 and 2, a cyan colorant and a yellow colorant are combined with “P.B.15: 3” and “P.Y.175”, respectively, and “P.B. .15: 3 ”and“ P.Y.213 ”, the green toner is particularly excellent in green reproducibility and printing performance.

Claims (4)

In a green toner comprising colored resin particles produced by suspension polymerization of a polymerizable monomer composition comprising at least a polymerizable monomer and a colorant in an aqueous dispersion medium containing a dispersion stabilizer,
A green toner, wherein the colorant is a cyan colorant and a yellow colorant.   The green toner according to claim 1, wherein the colorant has been surface-treated with a surface treatment agent.   The green toner according to claim 1, wherein the polymerizable monomer composition further contains a charge control resin.   The green toner according to claim 1, wherein the colored resin particles have a volume average particle diameter of 5 to 10 μm and an average circularity of 0.97 or more.