JP2009008989A - Full-color toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a full-color toner which hardly causes offset, particularly hot offset and winding of a recording material around a fuser, forms a full-color fixed image excellent in glossiness and color mixing properties, and yields a printed matter from which a man hardly gets eye strain even in the case of long-time reading. <P>SOLUTION: The full-color toner used in a full-color image forming apparatus in which a black toner becomes an uppermost layer on a recording material comprises a black toner, a magenta toner, a cyan toner and a yellow toner, wherein (a) toner base particles in each toner contain a binder resin, a colorant, a wax and a charge control agent, is formed by a kneading-grinding method and subjected to spheronization by heat treatment, (b) the binder resin of the toner base particles in the black toner is a styrene-(meth)acrylic ester copolymer, and (c) the binder resins of the toner base particles in the magenta, cyan and yellow toners are each a polyester resin. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a full-color toner, and more specifically, a full-color toner used in an image forming apparatus in which black toner is the uppermost layer on a recording material, and includes offset, particularly high-temperature offset, and winding of a recording material around a fixing device. A full-color toner that produces a full-color fixed image with excellent glossiness and color mixing, and a black text image on the top layer of the recording material that is less glossy. Is.

In the electrophotographic process, a latent image is electrostatically formed on a photoconductor using a photoconductive substance by various means, the latent image is developed with toner, and the toner image on the photoconductor is intermediately formed. In general, a fixed image is formed through a plurality of processes in which the transferred image is fixed on a recording material such as paper after being transferred to a recording material such as paper, with or without a transfer material. is there. In recent years, due to the development of equipment in the information society and the enhancement of communication networks, the electrophotographic process has become widely used not only for copiers but also for printers. High reliability has been increasingly demanded.
In particular, in the case of color electrophotography, the formed image is required to have high image quality and high color development. In order to obtain a high color image with high image quality, the toner must be sufficiently melted and the surface of the image after fixing must be smooth from the viewpoint of translucency (particularly OHP translucency) and gloss. . For this reason, the fixing step in the electrophotographic process is particularly important.
Full-color toner fixing is a superposition of four colors of black, magenta, cyan, and yellow, so if you want to obtain a fixed image that is glossy and excellent in color mixing, it will be offset (transfer to a non-image part of the recording material) Phenomenon) and winding of the recording material around the fixing device is likely to occur. In particular, when the temperature of the fixing device must be designed to be high as the speed of the machine increases, the toner has insufficient viscoelasticity and cannot be wound around the fixing device.
In Patent Documents 1 and 2, an attempt is made to improve all of high temperature offset, low temperature offset, fixing property, color mixing property, and glossiness by defining the storage elastic modulus G ′ of the toner. In the fixing of a full color image in which the upper and lower layers are superposed, the degree of melting of the upper layer toner and the lower layer toner (toner close to the recording material) is different, so that a satisfactory full color image cannot be obtained.
Patent Document 3 proposes a technique for controlling the difference in glossiness between a color image and a black-and-white image by slightly increasing the softening temperature of a black toner and increasing the softening temperature of a color (three-color) toner. Since the temperature is regulated to 100 ° C. or lower, the problem of winding around the fixing device cannot be cleared.
Patent Document 4 discloses a full-color fixing method in which a crosslinking component is present in the binder resin of the uppermost layer toner and the second layer toner on the recording material, and high-temperature offset is difficult while maintaining color mixing properties and glossiness. Has been. However, in this case, there is a problem that the surface smoothness of the fixed image of the second layer toner (yellow toner in the embodiment) becomes rough, and the yellow toner becomes an image having no gloss.
Recently, in order to obtain excellent developability and transferability, spherical toner has been put on the market. Spherical toner production methods are broadly classified into polymerization methods such as suspension polymerization and emulsion polymerization aggregation, and methods of spheroidizing particles obtained by kneading and pulverization with hot air at about 300 ° C. In the method of spheroidizing with hot air, the wax component oozes out on the surface of the toner during spheronization, deteriorating the durability and fluidity of the toner, and the toner melts to cause a particle size distribution. There is a problem of broadening. In order to solve these problems, Patent Document 5 attempts to use a specific wax having an acid value and provide a classification step after heat treatment spheroidization. In the case of superimposing, the recording material is easily wound around the fixing device, and it is necessary to increase the amount of the wax component added. In this case, it is inevitable that the wax exudes during heat treatment.
Japanese Patent Laid-Open No. 2005-91984 Japanese Patent Laid-Open No. 2002-131969 JP 2002-244349 A Japanese Patent Laid-Open No. 2-19861 JP 11-295929 A

  Under such circumstances, the present invention is less likely to cause offset, particularly high temperature offset, and wrapping of a recording material around a fixing device, and a full-color fixed image having excellent glossiness and color mixing properties can be obtained, and for a long time. The purpose of this invention is to provide a full-color toner that gives printed matter that does not get tired even when read.

As a result of intensive research to develop a full-color toner having the above-mentioned preferable properties, the present inventors are a full-color toner used in a full-color image forming apparatus in which the black toner is the uppermost layer on the recording material, By using a specific resin as a binder resin for toner base particles in black toner and magenta, cyan and yellow three color toners, the toner base particles in each toner are processed by a specific method. The present inventors have found that the object can be achieved, and have completed the present invention based on this finding.
That is, the present invention
[1] A full-color toner used in a full-color image forming apparatus in which black toner is the uppermost layer on the recording material, comprising black toner, magenta toner, cyan toner, and yellow toner,
(A) The toner base particles in each toner include a binder resin, a colorant, a wax, and a charge control agent, are formed by a kneading-pulverization method, and are formed by heat treatment spheroidization.
(B) the binder resin of the toner base particles in the black toner is a styrene- (meth) acrylic acid ester copolymer; and (c) the binder resin of the toner base particles in the three-color toner of magenta, cyan and yellow. Are polyester resins,
Full color toner, characterized by
[2] Item [1] above, wherein at least one color toner selected from magenta toner, cyan toner and yellow toner is obtained by diluting and kneading a master batch of a colorant prepared in advance. Full color toner as described in
[3] The storage elastic modulus G ′ of the toner at 170 ° C. is black toner: 100 to 2000 Pa and three-color toner: 30 to 1000 Pa, and G ′ of the black toner is larger than G ′ of the three-color toner The full color toner according to the above [1] or [2],
[4] The full color toner according to any one of [1] to [3] above, wherein the wax content in the toner base particles in each toner is 1 to 3% by mass, and [5] each toner Full color according to any one of [1] to [4] above, wherein 0.3 to 3 parts by mass of hydrophobic silica powder is added as an external additive to 100 parts by mass of spherical toner base particles. toner,
Is to provide.

  According to the present invention, the full color toner used in the image forming apparatus in which the black toner is the uppermost layer on the recording material, the offset, particularly the high temperature offset, and the recording material are less likely to be wound around the fixing device. A full-color fixed image with excellent glossiness and color mixing can be obtained, and since the gloss of the black text image on the top layer of the recording material is low, it is possible to provide a full-color toner that gives a printed matter that does not get tired even when read for a long time. .

The full-color toner of the present invention is a full-color toner used in a full-color image forming apparatus in which black toner is the uppermost layer on the recording material, and includes black toner, magenta toner, cyan toner, and yellow toner.
[Toner mother particles]
In the full-color toner of the present invention, the mother particles in each toner include a binder resin, a colorant, a wax, and a charge control agent, are formed by a kneading and pulverizing method, and are formed by a heat treatment spheronization process.
(Binder resin)
In the present invention, the black toner which is the uppermost layer of the recording material is used as a binder resin in the toner base particle from the viewpoint of high temperature offset and recording material to prevent the recording material from being wound around the fixing device, and from the viewpoint of gloss and fixability. Uses a styrene- (meth) acrylic acid ester copolymer, and a polyester resin for magenta, cyan and yellow color toners.
Although there is no restriction | limiting in particular in the styrene- (meth) acrylic acid ester copolymer used for the said black toner, For example, the copolymer of styrene and at least 1 sort (s) chosen from the following (meth) acrylic acid ester is mentioned. be able to. (Meth) acrylates include methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, methacrylic acid Examples thereof include butyl and octyl methacrylate.
The styrene- (meth) acrylic acid ester copolymer may be used alone or in combination of two or more. From the viewpoint of performance, styrene-butyl acrylate-butyl methacrylate. Is preferred.

Moreover, there is no restriction | limiting in particular in the polyester-type resin used for 3 color, However, What was obtained by the dehydration condensation of a polybasic acid and a polyhydric alcohol can be used.
Examples of polybasic acids include aromatic carboxylic acids such as terephthalic acid, isophthalic acid, phthalic anhydride, trimellitic anhydride, pyromellitic acid, naphthalenedicarboxylic acid; maleic anhydride, fumaric acid, succinic acid, alkenyl succinic anhydride Aliphatic carboxylic acids such as acid and adipic acid; and alicyclic carboxylic acids such as cyclohexanedicarboxylic acid. These polybasic acids can be used alone or in combination of two or more. Of these polybasic acids, aromatic carboxylic acids are preferably used.
Examples of the polyhydric alcohol include aliphatic diols and polyols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, glycerin, trimethylolpropane, and pentaerythritol; cyclohexanediol, Examples include alicyclic diols such as cyclohexanedimethanol and hydrogenated bisphenol A; aromatic diols such as ethylene oxide adduct of bisphenol A and propylene oxide adduct of bisphenol A. These polyhydric alcohols can be used alone or in combination of two or more. Among these polyhydric alcohols, aromatic diols and alicyclic diols are preferable, and aromatic diols are more preferable.
The polyester resin may be used alone or in combination of two or more. From the viewpoint of performance, a polycondensation polyester of an aromatic dicarboxylic acid and an alkylene etherified bisphenol A is suitable. is there.
The styrene- (meth) acrylic acid ester copolymer and polyester resin used as the binder resin preferably have a glass transition temperature of 50 to 75 ° C, and more preferably 52 to 70 ° C. When the glass transition temperature is less than 50 ° C., the storage stability of the toner may be lowered, and when the glass transition temperature exceeds 75 ° C., the low-temperature fixability of the toner may be insufficient.
Note that when the four-color toner is a toner using a styrene- (meth) acrylate copolymer as a binder resin, it is effective with respect to high-temperature offset resistance and wrapping around a fixing device. Since the color mixing property of the fixed image is hindered or gloss is lost, it is not preferable as a photographic image.

(Coloring agent)
As the colorant in the toner base particles, a black colorant is used for black toner, a yellow colorant for yellow toner, a cyan colorant for cyan toner, and a magenta colorant for magenta toner.
As the black colorant, carbon black, manganese dioxide, aniline black, activated carbon and the like are used.
As the yellow colorant, compounds represented by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds are used. Specifically, CI Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 109, 110, 111, 128, 129, 147, 169, 180, etc. Preferably used.
As the cyan colorant, copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, basic dye lake compounds, and the like are used. Specifically, CI pigment blue 1,7,15,15: 1,15: 2,15: 3,15: 4,60,62,66 and the like are particularly preferable.
As the magenta colorant, a condensed azo compound, diketopyrrolopyrrole compound, asosuraquinone, quinacridone compound, basic dye lake compound, naphthol compound, benzimidazolone compound, thioindigo compound, and perylene compound are used. Specifically, CI Pigment Red 2,3,5,6,7,23,48: 2,48: 3,48: 4,57: 1,81: 1,122,144,146,166 , 169, 177, 184, 185, 202, 206, 220, 221, 254 are particularly preferred.

(wax)
In the present invention, the wax used for the toner base particles is used for the purpose of improving the releasability at the time of heat roll fixing, and examples thereof include plant waxes such as carnauba wax and rice wax, Petroleum wax such as paraffin wax and microcrystalline wax, mineral wax such as montan wax and canderia wax, synthetic wax such as carbowax, polyethylene wax, polypropylene wax, ethylene-propylene copolymer wax, chlorinated naphthalene wax, stearic acid , Higher fatty acids such as arachidic acid and behenic acid, higher alcohols such as seryl alcohol and melyl alcohol, amide waxes such as stearic acid amide and behenic acid amide, fatty acid esters, glycerin monostearate Over DOO, polyhydric alcohol esters such as glycerin distearate, and the like silicone varnish. These waxes can be used alone or in combination of two or more.
The melting point of this wax is preferably 50 to 160 ° C, more preferably 60 to 150 ° C. If the melting point of the wax is less than 50 ° C., the storage stability of the toner may be reduced, and if the melting point of the wax exceeds 150 ° C., the low-temperature fixability of the toner may be insufficient. The melting point of the wax can be determined as an endothermic peak temperature when the temperature is raised at 10 ° C./min in an analysis using a differential scanning calorimeter (DSC).
In the present invention, the wax content in the toner base particles is preferably 0.5 to 5% by mass, and more preferably 1 to 3% by mass. If the wax content is less than 0.5% by mass, the low-temperature fixability of the toner may be insufficient. When the wax content exceeds 5% by mass, adhesion and deposition of particles are likely to occur in the production process. In particular, the wax component tends to ooze out during the heat treatment spheroidization, thereby lowering the charging performance of the toner. In addition, the fluidity and storage stability of the toner may be reduced.

(Charge control agent)
In the present invention, the charge control agent used for the toner base particles may be, for example, a monoazo metal compound, an acetylacetone metal compound, an aromatic hydroxycarboxylic acid, a metal-containing salicylic acid compound, boron, Examples thereof include complex compounds and calixarene. Examples of the charge control agent that controls the toner to be positively charged include tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, nigrosine, guanidine compound, triphenylmethane dye, and quaternary ammonium salt. be able to.
Since the present invention is a full-color toner, a colorless, white, or light-colored charge control agent that does not adversely affect the color tone and light transmittance among the above-described charge control agents is used for the three colors magenta, cyan, and yellow. Is possible. As the charge control agent used for the black toner, a colored material such as black can be used. For example, a negatively chargeable charge control agent such as a metal-containing type or a metal-free type, and a positively chargeable charge control agent such as a nigrosine type or triphenylmethane type can be used. When adding a charge control agent, about 0.1-10 mass parts is normally used with respect to 100 mass parts of binder resin.
By incorporating these charge control agents into the toner base particles, the charging characteristics of the toner can be stabilized and fogging can be prevented. These charge control agents may be used individually by 1 type, and may be used in combination of 2 or more type.

(Silica powder)
The toner base particles in the present invention can contain silica powder as an internal additive if desired. By containing this silica powder, a wax having a low affinity with the binder resin is adsorbed on the aggregate of silica particles, and is uniformly dispersed in the binder resin, thereby preventing the toner particles from exuding to the surface. As a result, the fluidity of the pulverized toner particles is improved, and adhesion and accumulation in the manufacturing apparatus are prevented.
The average primary particle diameter of the silica powder used in the present invention is preferably 0.005 to 0.02 μm, and more preferably 0.007 to 0.016 μm.
The silica powder is not particularly limited, and examples thereof include dry method silica, wet precipitation method silica, and wet gel method silica. Also, any of hydrophilic silica having a large number of silanol groups and hydrophobic silica hydrophobized with trimethylsilylation of silanol groups or silicone oil can be used. Among these, hydrophobic silica is particularly suitable because it has a high affinity with the binder resin.
The content of silica powder in the toner base particles is usually about 0.25 to 5% by mass. If the content of the silica powder is less than 0.25% by mass, the effect of adsorbing and holding the wax may not be sufficiently exhibited. When the content of the silica powder exceeds 5% by mass, the fixing property of the toner is inhibited, and in the case of a color toner, the transparency of the toner may be lowered.

<Hydrophobic silica powder>
As a material of a hydrophobic silica powder preferable as an internal additive, a halogenated silane such as silicon tetrachloride is produced by vapor phase oxidation, so-called dry silica powder called fumed silica, and so-called water glass is used. Although either can be used wet silica powder, less silanol groups on the surface and inside, also Na ₂ O, SO ₃ ^- less dry silica powder of manufacture residues such as is preferred.
Examples of the treatment agent used for the hydrophobic treatment of the silica powder include silicone varnish, various modified silicone varnishes, silicone oil, various modified silicone oils, silazane compounds, cyclic dimethylsiloxane, and silane coupling agents. Among these, silicone oil, silazane compound, cyclic dimethylsiloxane, and silane coupling agent are preferable.
Examples of the silicone oil include dimethyl silicone oil, methylphenyl silicone oil, α-methylstyrene-modified silicone oil, fluorine-modified silicone oil, etc., examples of the silazane compound include hexamethyldisilazane, and examples of the cyclic dimethylsiloxane include hexagonal dimethylsiloxane. Examples include methylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and the like. Examples of silane coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, methyltrimethoxysilane, methyltriethoxysilane, isobutyltrimethoxysilane, dimethyldimethoxysilane. Dimethyldiethoxysilane, trimethylmethoxysilane, hydroxypropyltrimethoxysilane, phenyltrimethoxysilane, n-hexadecyltrimethoxysilane, n-octadecyltrimethoxysilane and the like.

(Preparation of each toner base particle)
In the present invention, each toner base particle can be prepared by the following method.
First, a binder resin, a colorant, a wax, a charge control agent, and optionally silica powder are melt-kneaded. There is no particular limitation on the method of melt-kneading, for example, these materials are mixed in advance using a ribbon mixer, a double cone mixer, a high speed mixer, a cone screw mixer, etc., and then a Banbury mixer, It can be melt-kneaded using a twin-screw kneading extruder or the like.
In many cases, organic pigments are used as color toner colorants for yellow, cyan, and magenta. If these organic pigments are not finely dispersed at the time of kneading, excellent color mixing properties can be achieved even when the toner is melted by heat. Is difficult to obtain. Accordingly, it is preferable to prepare a master batch of pigment in advance and finely disperse the pigment, and then mix and melt knead the remaining binder resin, wax, charge control agent and, if desired, fine silica powder.
There is no restriction | limiting in particular in the method of kneading | mixing a masterbatch, A well-known method can be used.
For example, a method using a two-roll, a three-roll, a Banbury mixer, a pressure kneader, or the like, or a flushing method can be employed.
The pigment concentration in the master batch is about 20 to 45% by mass, preferably 30 to 40% by mass, and the binder resin used for master batch kneading may be the same as the resin used for dilution kneading, If the monomer components are similar, the molecular weight distribution may be different.
The melt-kneaded product is pulverized after cooling. Examples of the pulverizer used include impact pulverizers such as impact crushers and hammer crushers, impact pulverizers such as rod mills and ball mills, and jet pulverizers using a compressed air source such as a counter jet mill. it can. The pulverized particles are preferably classified into toner particles having a narrow particle size distribution by removing coarse particles and fine particles. There is no restriction | limiting in particular in the classification method, For example, it can classify | categorize using an airflow classifier etc.
In the method of the present invention, the particles are spheroidized by heat treatment in a floating state using the powder whose particle size distribution is narrowed by classification as toner base particles. In the heat treatment, the productivity of the spheronization process can be improved by externally adding silica powder, preferably hydrophobic silica powder, as a fluidizing agent in advance. The addition amount of the externally added silica is preferably 0.1 to 3 parts by mass, more preferably 0.3 to 2 parts by mass with respect to 100 parts by mass of the toner base particles. As a means for heat-treating the toner mother particles, for example, a fluidized bed tank or a hot air spheronizing device for dispersing the toner mother particles in a hot air flow and melting the surface to spheroidize can be used. By the heat treatment, the average circularity of the toner particles is preferably 0.930 to 0.980 which is excellent in transferability, and the average circularity is more preferably 0.945 to 0.970.
The method for measuring the average circularity will be described later.
In addition, when melt-kneading the binder resin, colorant, wax, charge control agent and optionally silica powder, a masterbatch containing the binder resin and the colorant is prepared according to a conventional method and used in place of the colorant. Can do.

[Full Color Toner]
Hydrophobic silica powder as an external additive is preferably used in an amount of 0.3 to 3 parts by mass, more preferably 0.8 to 2.5 parts by mass with respect to 100 parts by mass of each toner base particle prepared as described above. The full color toner of the present invention consisting of black toner, yellow toner, cyan toner and magenta toner can be obtained. The addition of the hydrophobic silica powder is performed for adjusting the charging characteristics and fluidity of the toner.
In the full color toner of the present invention thus obtained, the storage elastic modulus G ′ of the toner at 170 ° C. is 100 to 100 for black toner from the viewpoint of suppressing high temperature offset and winding of the recording material around the fixing device. It is desirable that the pressure is 2000 Pa, preferably 300 to 1800 Pa, and it is 30 to 1000 Pa, preferably 40 to 900 Pa, for the three color toners of yellow, cyan and magenta. It is desirable that G ′ of the black toner is larger than G ′ of the three-color toner.
A method for measuring the storage elastic modulus G ′ will be described later.
The full-color toner of the present invention can give a full-color fixed image that is less likely to cause an offset, particularly a high-temperature offset, or a recording material to be wound around a fixing device, and is excellent in glossiness and color mixing. Further, since the black character image printed on the uppermost layer of the recording material is less glossy, it is possible to give a printed matter that is less tiring even when read for a long time.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
In addition, the measurement and evaluation of various characteristics in each example were performed by the following methods.
(1) Average circularity of spheroidized toner particles Using a flow particle image analyzer [manufactured by Sysmex Corporation, model name “FPIA-2100”], the average circularity of particles having an equivalent circle diameter of 3 μm or more is determined.
Circularity = (circumference of a circle having the same area as the projected area of the particle) / (contour length of the particle projection)
(2) Storage modulus G ′ of toner
A 20.6 N / mm ² load is applied to the toner to be measured using a pellet molding machine for 1 minute to produce a pellet having a diameter of 25 mm and a thickness of 3 mm, which is used as a measurement sample. With respect to this sample, using an Ares viscoelasticity measurement system manufactured by TA Instruments Co., Ltd. under the conditions of strain 1.0%, frequency 1.0 Hz, start temperature 100 ° C., temperature increase rate 3 ° C./min, 170 ° C. The storage elastic modulus G ′ at is measured.
(3) Winding property to fixing device For evaluation, a tandem full-color laser printer equipped with a non-magnetic one-component developing device (manufactured by Hewlett-Packard Company, model name “HP CLJ5550”) is used for recording during fixing. The toner on the material (paper) is the uppermost layer: black, the second layer: magenta, the third layer: cyan, and the lowermost layer: yellow.
Printed image (A) JIS X 9201-1995 (Standard object color spectral database for color reproduction evaluation) N3 image (B) JIS X 9201-1995 (Standard object color spectral database for color reproduction evaluation) N7 image (C) Yellow and cyan Solid image with two colors superimposed (green)
(D) Solid image (red) with two colors of magenta and yellow superimposed
(E) Solid image in which cyan and magenta are superimposed (blue)
Ten images of the above (a) to (e) are printed continuously and evaluated according to the following criteria.
○: No winding around the fixing device occurs.
Δ: Wrapping around the fixing device was not achieved, but the back of the separation claw is seen in a streak shape in the printed image.
X: Winding around the fixing device occurs.
(4) Glossy Printed Image ・ Black Single Color Solid ・ Cyan Single Color Solid ・ Magenta Single Color Solid ・ Yellow Single Color Solid ・ The above (C) Solid image with two colors of yellow and cyan superimposed (green)
・ (D) Solid image (red) with two colors of magenta and yellow superimposed
・ (E) Solid image (blue) with two colors of cyan and magenta superimposed
The printed image is evaluated according to the following criteria using a measuring device [Minolta, model name “Uni-Gloss60”].
○: 4.0 or more △: 2.0 or more and less than 4.0 ×: Less than 2.0 (5) Fixing Printed image ・ Black single color solid ・ Magenta single color solid ・ Cyan single color solid ・ Yellow single color solid ・ Above (C) Solid image with two colors of yellow and cyan superimposed (green)
・ (D) Solid image (red) with two colors of magenta and yellow superimposed
・ (E) Solid image (blue) with two colors of cyan and magenta superimposed
Method The image density of each image is measured in advance with a “Macbeth densitometer RD-19” manufactured by Macbeth, and the cellophane adhesive tape is peeled off after being adhered to the printing surface, and the image density after peeling is measured. The fixability is calculated by the following formula.
Fixability = [(Image density after tape peeling / Image density before tape peeling)] × 100 (%)
○: 95% or more △: 85% or more, less than 95% ×: less than 85%

Production Example 1 Production of Black Toner (Styrene-Acrylic Copolymer Type) Styrene-butyl acrylate copolymer [trade name “PA-805” manufactured by Mitsui Chemicals, Inc., Tg: 60 ° C., number average molecular weight (Mn) as a binder resin ): 3200, weight average molecular weight (Mw): 266000, acid value: 6.5 mg KOH / g] 91.0 parts by mass, carbon black [manufactured by Cabot, trade name “Black Pearls L”] 5.0 parts by mass , 1.5 parts by mass of charge control agent [Orient Chemical Industries, trade name “Bontron E-304”] and 2.5 parts by weight of wax [Sanyo Chemical Industries, trade name “Yumex 110TS”] After mixing with a mixer [Mitsui Mining Co., Ltd., model name “75L Henschel Mixer”], with a twin screw extruder [Ikegai Co., Ltd., model name “PCM30”] It was melt-kneaded. At this time, the outlet temperature of the twin screw extruder was 153 ° C.
Next, this melt-kneaded product was cooled and then pulverized to a volume average particle size of 8.2 μm with a jet type pulverizer [manufactured by Hosokawa Micron Corporation, model name “Counter Jet Mill”]. Subsequently, the pulverized product was classified into coarse powder and fine powder by an airflow classifier [manufactured by Nippon Steel & Mining Co., Ltd., model name “Elbow Jet EJ-PURO”] to obtain toner base particles having a sharp particle size distribution. .
Next, 0.5 parts by mass of hydrophobic silica [manufactured by Cabot, trade name “TS-530”, BET specific surface area 225 m ² / g] is added as a pre-external additive to 100 parts by mass of the toner base particles. After mixing with a Henschel mixer “20 L Henschel mixer” (supra), heat treatment was performed at a hot air temperature of 360 ° C. using a hot air spheronizer [manufactured by Nippon Pneumatic Kogyo Co., Ltd., model name “SFS-3”] Spherical toner particles having an average circularity of 0.963 and a volume average particle size of 8.6 μm were obtained.
Finally, to 100 parts by mass of the spheroidized toner particles, 0.5 parts by mass of hydrophobic silica “TS-530” (supra) and hydrophobic silica [made by Nippon Aerosil Co., Ltd., trade name “RX” A black toner was manufactured by adding 1.5 parts by mass of “-50” and a BET specific surface area of 35 m ² / g] and mixing with a Henschel mixer “20 L Henschel mixer” (supra). The storage modulus G ′ of this black toner at 170 ° C. was 600 Pa.

Comparative Production Example 1 Production of Black Toner (Polyester Type) In Production Example 1, a polyester resin [Tg: 61 ° C., Mn: 3400, Mw: 133800, acid value: 5.0 mgKOH / g] was used as the binder resin. In the same manner as in Production Example 1, after mixing with a Henschel mixer, melt kneading was performed with a twin screw extruder. At this time, the outlet temperature of the twin screw extruder was 144 ° C.
Next, in the same manner as in Production Example 1, the melt-kneaded product was subjected to pulverization, classification, external addition before spheronization, heat treatment spheronization, and post-external addition to produce a black toner.
The volume average particle size of the pulverized product was 8.3 μm. The hot air temperature for heat treatment spheronization was 300 ° C., the average circularity of this spheronized product was 0.965, and the volume average particle size was 8.6 μm. Further, the storage elastic modulus G ′ at 170 ° C. of the black toner was 90 Pa.
Comparative Production Example 2 Production of Black Toner (Polyester Type) In Production Example 1, polyester resin [Tg: 61 ° C., Mn: 4000, Mw: 206000, acid value: 5.5 mgKOH / g] was used as the binder resin. In the same manner as in Production Example 1, after mixing with a Henschel mixer, melt kneading was performed with a twin screw extruder. At this time, the outlet temperature of the twin screw extruder was 147 ° C.
Next, in the same manner as in Production Example 1, the melt-kneaded product was subjected to pulverization, classification, external addition before spheronization, heat treatment spheronization, and post-external addition to produce a black toner.
The volume average particle size of the pulverized product was 8.0 μm. The hot air temperature for heat treatment spheronization was 320 ° C., the average circularity of this spheronized product was 0.963, and the volume average particle size was 8.5 μm. Further, the storage elastic modulus G ′ at 170 ° C. of the black toner was 300 Pa.

Production Example 2 Production of Yellow Toner 70 parts by mass of a polyester resin [Tg: 61 ° C., Mn: 3400, Mw: 133800, acid value: 5.0 mgKOH / g] as a binder resin and “CI Pigment Yellow as a yellow pigment” 30 parts by weight of 180 ”was premixed with a Henschel mixer“ 20L Henschel mixer ”(supra), melt-kneaded with a Banbury mixer [manufactured by Nippon Roll Co., Ltd., model name“ 5L intensive mixer ”], and after cooling, A yellow pigment master batch was prepared by crushing to a size of 3 mm or less.
Subsequently, 82.7 parts by mass of a polyester resin (supra), 13.3 parts by mass of the yellow pigment master batch, 1.5 parts by mass of a charge control agent “Bontron E-304” (supra) and wax “Yumex 110TS” ( As mentioned above, 2.5 parts by weight of 2.5 parts by mass are premixed with a Henschel mixer “75L Henschel mixer” (above), then melt-kneaded with a twin screw extruder “PCM30” (above), and after cooling, about 3 mm or less Crushed to size.
Next, in the same manner as in Production Example 1, this coarsely crushed product was subjected to pulverization, classification, external addition before spheronization, spheroidization after heat treatment, and post-external addition to produce a yellow toner.
The volume average particle size of the pulverized product was 8.1 μm. The hot air temperature for heat treatment spheronization was 300 ° C., the average circularity of this spheronized product was 0.965, and the volume average particle size was 8.5 μm. Further, the storage elastic modulus G ′ of the yellow toner at 170 ° C. was 95 Pa.

Production Example 3 Production of Cyan Toner 70 parts by mass of a polyester resin [Tg: 61 ° C., Mn: 3400, Mw: 133800, acid value: 5.0 mgKOH / g] as a binder resin, and CI pigment blue as a cyan pigment 15: 3 ”30 parts by mass is premixed with a Henschel mixer“ 20L Henschel mixer ”(supra), then melt-kneaded with a Banbury mixer“ 5L intensive mixer ”(previously), and after cooling, about 3 mm or less. Cyan pigment masterbatch was prepared by crushing to size.
Next, 82.7 parts by mass of the polyester resin (supra), 13.3 parts by mass of the cyan pigment master batch, 1.5 parts by mass of the charge control agent “Bontron E-304” (supra) and the wax “Yumex 110TS” ( As mentioned above, 2.5 parts by weight of 2.5 parts by mass are premixed with a Henschel mixer “75L Henschel mixer” (above), then melt-kneaded with a twin screw extruder “PCM30” (above), and after cooling, about 3 mm or less Crushed to size.
Next, in the same manner as in Production Example 1, the coarsely pulverized product was subjected to pulverization, classification, external addition before spheronization, spheroidization after heat treatment, and post-external addition to produce a cyan toner.
The volume average particle size of the pulverized product was 8.1 μm. The hot air temperature for the heat treatment spheronization was 300 ° C., the average circularity of this spheronized product was 0.966, and the volume average particle size was 8.6 μm. The storage elastic modulus G ′ of the cyan toner at 170 ° C. was 90 Pa.

Production Example 4 Production of Magenta Toner 70 parts by mass of a polyester resin [Tg: 61 ° C., Mn: 3400, Mw: 133800, acid value: 5.0 mgKOH / g] as a binder resin and “CI Pigment Red” as a magenta pigment 122 "30 parts by mass is premixed with a Henschel mixer" 20L Henschel mixer "(supra), melt-kneaded with a Banbury mixer" 5L intensive mixer "(supra), and cooled to a size of about 3 mm or less. Crushing to prepare a magenta pigment master batch.
Next, 82.7 parts by mass of the polyester resin (supra), 13.3 parts by mass of the magenta pigment master batch, 1.5 parts by mass of the charge control agent “Bontron E-304” (supra) and the wax “Yumex 110TS” ( As mentioned above, 2.5 parts by weight of 2.5 parts by mass are premixed with a Henschel mixer “75L Henschel mixer” (above), then melt-kneaded with a twin screw extruder “PCM30” (above), and after cooling, about 3 mm or less Crushed to size.
Next, in the same manner as in Production Example 1, this coarsely pulverized product was subjected to pulverization, classification, external addition before spheronization, spheroidization after heat treatment, and post external addition to produce a magenta toner.
The volume average particle size of the pulverized product was 8.0 μm. The hot air temperature for heat treatment spheronization was 300 ° C., the average circularity of this spheronized product was 0.963, and the volume average particle size was 8.4 μm. Further, the storage elastic modulus G ′ at 170 ° C. of the magenta toner was 150 Pa.

Example 1
Using the black toner obtained in Production Example 1, the yellow toner obtained in Production Example 2, the cyan toner obtained in Production Example 3, and the magenta toner obtained in Production Example 4, the winding property to the fixing device and gloss・ Fixability was evaluated. The results are shown in Table 1, Table 2 and Table 3, respectively.
Comparative Example 1
Using the black toner obtained in Comparative Production Example 1, the yellow toner obtained in Production Example 2, the cyan toner obtained in Production Example 3, and the magenta toner obtained in Production Example 4, Gloss / fixability was evaluated. The results are shown in Table 1, Table 2 and Table 3, respectively.
Comparative Example 2
Using the black toner obtained in Comparative Production Example 2, the yellow toner obtained in Production Example 2, the cyan toner obtained in Production Example 3, and the magenta toner obtained in Production Example 4, Gloss / fixability was evaluated. The results are shown in Table 1, Table 2 and Table 3, respectively.

The meanings of the abbreviations in each table are as follows.
Bk single color: black single color solid image M single color: magenta single color solid image C single color: cyan single color solid image Y single color: yellow single color solid image Y / C: solid image obtained by superimposing two colors of yellow and cyan M / Y: magenta Solid image in which two colors of yellow are superimposed C / M: Solid image in which two colors of cyan and magenta are superimposed As can be seen from Tables 1 to 3, in Example 1, which is the full color toner of the present invention, Wrapping around the fixing device does not occur, and the gloss of the black single-color solid image is low.

  The full-color toner of the present invention is less susceptible to offset, particularly high-temperature offset, and wrapping of the recording material around the fixing device, and can provide a full-color fixed image excellent in gloss and color mixing, and black characters on the uppermost layer of the recording material. Since the gloss of the image is small, it is possible to give a printed matter in which the eyes do not get tired even when read for a long time.

Claims (5)

A full-color toner used in a full-color image forming apparatus in which black toner is the uppermost layer on the recording material, comprising black toner, magenta toner, cyan toner, and yellow toner,
(A) The toner base particles in each toner include a binder resin, a colorant, a wax, and a charge control agent, are formed by a kneading-pulverization method, and are formed by heat treatment spheroidization.
(B) the binder resin of the toner base particles in the black toner is a styrene- (meth) acrylic acid ester copolymer; and (c) the binder resin of the toner base particles in the three-color toner of magenta, cyan and yellow. Are polyester resins,
Full color toner characterized by   2. The full color toner according to claim 1, wherein at least one color toner selected from a magenta toner, a cyan toner and a yellow toner is obtained by diluting and kneading a master batch of a colorant prepared in advance. .   The storage elastic modulus G ′ of the toner at 170 ° C. is black toner: 100 to 2000 Pa and three-color toner: 30 to 1000 Pa, and G ′ of the black toner is larger than G ′ of the three-color toner. Or the full-color toner according to 2.   The full-color toner according to claim 1, wherein the wax content in the toner base particles in each toner is 1 to 3% by mass.   5. The toner according to claim 1, wherein each toner contains 0.3 to 3 parts by mass of hydrophobic silica powder as an external additive with respect to 100 parts by mass of the spherical toner base particles. Full color toner.