JP2006145703A - Yellow toner for electrophotography, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide toner having wide color reproduction, light resistance and safety in yellow toner corresponding to small diameter toner by simplifying an oil application mechanism in fixing. <P>SOLUTION: In the yellow toner used in a full color image forming apparatus of a dry electrophotographic method, the toner contains at least a C.I. Pigment Yellow 185, a binder resin, and a releasing agent. A weight average particle diameter D4 is 2.0-8.0 μm and a toner adhesion amount indicating yellow image density of 1.3 is in the range of 0.1-0.5 mg/cm<SP>2</SP>. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a yellow toner used in a dry electrophotographic full-color image forming apparatus and a dry electrophotographic full-color image forming apparatus.

As the yellow toner used in the dry electrophotographic full-color image forming apparatus, various highly safe colorants that do not generate benzidine corresponding to the German blue angel mark have been proposed.
In Patent Document 1, Patent Document 2, and Patent Document 3, C.I. I. Pigment Yellow 180 has been proposed. Patent Document 4 proposes Solvent Yellow 162 and Patent Document 5 proposes a monoazo yellow pigment.
However, with these materials, a wide color reproduction range cannot be obtained with the small particle size oilless color toner, which is necessary for downsizing the machine and improving the image quality.

  In a dry electrophotographic full-color image forming apparatus, the toner particle size is reduced to 8.0 μm or less in order to cope with high definition and high image quality. As the toner has a smaller particle size, when the degree of coloring is the same as that of the toner before the particle size reduction, the number of toner layers increases and dust is likely to occur. In a small particle size toner, the pigment concentration of the toner is increased to increase the degree of coloring, reduce the amount of adhesion, reduce the number of toner layers, and prevent toner dust. By increasing the pigment concentration, the dispersion of the pigment falls and the color reproduction range decreases. Further, in order to simplify the fixing unit, a release agent is included in the toner to simplify the oil application mechanism of the fixing unit. Due to the release agent in the toner, the light transmittance of the toner is deteriorated and the color reproduction range is lowered.

JP-A-6-230607 JP-A-6-266163 Japanese Patent Laid-Open No. 10-268572 JP-A-8-87160

  Accordingly, the present invention has been made to solve the above-described problems, and it is a yellow toner corresponding to a small particle size toner that simplifies the oil application mechanism in fixing, and has wide color reproducibility, light resistance, and safety. An object is to provide a toner that can be used.

The above problem is (1) “Yellow toner used in a dry electrophotographic full-color image forming apparatus of the present invention, and the toner includes at least CI Pigment Yellow 185, a binder resin, a release agent. And a weight average particle diameter D4 of 2.0 to 8.0 μm, and a toner adhesion amount for producing a yellow image density of 1.3 is in the range of 0.1 to 0.5 mg / cm ^2. “Yellow Toner”, (2) “Weight average particle diameter D4 is 3.0 to 6.0 μm, and the toner adhesion amount for producing a yellow image density of 1.3 is in the range of 0.1 to 0.4 mg / cm ^2. (3) “The amount of CI Pigment Yellow 185 in the toner is 5 to 30% by weight”. 1) or Yellow toner according to item (2), (4) “Yellow toner according to any one of items (1) to (3), characterized in that the binder resin contains a branched structure. (5) “The binder resin is mainly composed of a polyester resin, and the release agent is composed mainly of an ester wax or carnauba wax. It is solved by the yellow toner described in any one.
Further, the above-described problem is solved by using a dry electrophotographic full-color image forming apparatus using the yellow toner according to any one of (6) and (1) to (5) of the present invention. (7) “Yellow toner according to any one of (1) to (5), cyan toner having CI Pigment Blue 15-3 as a main component of colorant, and C.I. The present invention is solved by a dry electrophotographic full-color image forming apparatus characterized by using magenta as a main component of a colorant of CI Pigment Red 122 or CI Pigment Volet 19.

  As will be apparent from the following detailed and specific description, according to the present invention, C.I. I. By using Pigment Yellow 185, etc., the pigment concentration in the toner is high, the dispersibility in the binder resin is excellent, the L * value and the C * value are large, bright, vivid and wide color reproduction and excellent light resistance. A very excellent effect is provided in that a yellow toner that can form a color image and is excellent in light resistance and safety, and a dry electrophotographic full color image forming apparatus using the toner are provided.

  The dry electrophotographic full-color image forming apparatus can obtain a high-definition image as the toner particle size is reduced. When the weight average particle diameter D4 of the toner is 2.0 to 8.0 μm, more preferably 3.0 to 6.0 μm, a high-definition image can be obtained. When the weight average particle diameter D4 of the toner exceeds 8.0 μm, the toner particles forming the image are large and it is difficult to faithfully develop the latent image on the fine photoconductor. When the weight average particle diameter D4 of the toner is less than 2.0 μm, the influence of the physical properties on the toner surface becomes large, the aggregation between the toners becomes strong, the handling of the toner becomes difficult, and the problem in image formation becomes large. Become. In addition, since the particle size is small, the toner is likely to rise and easily enter the human respiratory organs, and the toner is difficult to come out from the body, which may cause a problem in terms of safety.

Since the toner of the present invention has a smaller particle diameter compared to the conventional toner, the degree of coloring of the toner is increased.
To obtain a certain level of image density, a certain amount of toner adhesion is required. When the toner particle size is small, the number of toners in the vertical direction increases when a certain amount of toner is adhered, and the toner layer becomes unstable. For this reason, the toner is likely to be scattered and an unclear image is likely to be obtained. In particular, in a full-color image, the toner is overlapped in order to produce various colors, so that the toner layer becomes thicker and the toner becomes more easily dusty.
Accordingly, in the present invention, the pigment concentration in the toner is increased to produce a high image density with a low adhesion amount, thereby reducing the number of toners in the vertical direction and preventing image dust.

Specifically, the minimum image density that can be recognized as a solid yellow image is about 1.3. If the degree of coloring is such that the toner density is 0.1 to 0.5 mg / cm ² and the image density is 1.3, toner scattering can be reduced. Further, when the toner weight average particle diameter D4 is 3.0 to 6.0 μm, the coloration degree is such that the toner adhesion amount is 0.1 to 0.4 mg / cm ² and the image density is 1.3. It has been found in the present invention that toner scattering can be reduced.

In the image forming apparatus of the present invention, after transferring the toner onto paper or the like, the image is fixed by applying pressure and heat to the toner and fusing the toner with a fixing machine equipped with a heat roller, a heat film, a heat belt, etc. . The toner of the present invention simplifies the oil application mechanism by including a release agent in the toner, thereby improving the releasability from the heat roller, heat film, and heat belt. Depending on the fixing machine, there are a mechanism in which the oil application mechanism is completely removed, and a simplified mechanism in which a small amount of oil is applied using a roller or sheet impregnated with oil instead of applying oil from the oil tank.
In a dry electrophotographic full-color image forming apparatus, downsizing is an important factor from the viewpoint of cost and ease of use, and a fixing machine with a simplified oil application mechanism is required.

A toner having a coloration degree in which the weight average particle diameter D4 is 2.0 to 8.0 μm, and the toner adhesion amount for producing a yellow image density of 1.3 is in the range of 0.1 to 0.5 mg / cm ² ; In the case of a yellow toner containing a release agent, a toner satisfying all of sufficient transparency, color developability, and weather resistance has not been obtained conventionally.
This is because the toner particle size is small and the colorant concentration in the toner is large, so that the light transmission property is deteriorated. This is because light is scattered and the light transmission is further deteriorated.

For this reason, in the present invention, C.I. I. This problem was solved by using Pigment Yellow 185.
C. I. Pigment Yellow 185 has high transparency of the pigment crystal itself and a high degree of coloring, so that the concentration of the colorant can be kept low compared to other colorants, and the transparency of the toner can be maintained. It has been found in the present invention that this can be done. Also, the dispersibility of the pigment in the resin is good.
Furthermore, C.I. I. Pigment Yellow 185 is easy to transmit light with a wavelength of 480 to 530 nm, and has a greenish color. Since it is easy to transmit light with a wavelength of 480 to 530 nm, when green is formed by overlapping cyan, the transmittance of the portion with a wavelength of 480 to 530 nm is increased, and a vivid green can be produced, and a wide color reproduction range is achieved. Obtainable.
In addition, C.I. I. Pigment Yellow 185 has good light resistance.
Furthermore, C.I. I. From the molecular formula of Pigment Yellow 185, it does not contain the structure of carcinogenic substances such as benzidine or chlorine, and is considered to be highly safe.
In the present invention, this C.I. I. The amount of Pigment Yellow 185 is preferably 5 to 30% by weight, and more preferably 8 to 20% by weight.

Next, problems with the currently proposed colorants are described.
C. I. About Pigment Yellow 13, 14, and 17, the molecular structure includes the structure of benzidine, which is a carcinogenic substance, and there is a concern in terms of safety when the pigment is decomposed. Also, the light resistance is not so high, and color resistance becomes a problem when using images in places exposed to direct sunlight.

  C. I. Pigment Yellow 74 contains the structure of anisidine, which is a carcinogenic substance, in the molecular structure, and there is a concern in terms of safety when the pigment is decomposed. Light resistance is not so high, and color resistance becomes a problem when using images in places exposed to direct sunlight. In addition, since the crystal of the pigment is unstable, it is generally stabilized by increasing the particle size of the crystal. Therefore, the transparency is low, and there is a problem in the color developability when the pigment concentration is increased. .

  C. I. Pigment Yellow 93 contains chlorine in its molecular structure, and there is concern about the generation of dioxins during incineration. Although the light resistance is high, since the color is not greenish, the color developability of green superimposed with cyan toner falls when a release agent is added.

  C. I. Pigment Yellow 128 contains chlorine in its molecular structure, and there is a concern that dioxins may be generated during incineration. Light resistance is high, and the color is also greenish, but the coloring degree of the pigment itself is low. For this reason, in the case of a toner having a high degree of coloring as in the present invention, it is necessary to greatly increase the pigment concentration, which causes a problem in transparency and cost.

  C. I. Pigment Yellow 155 has high safety and high light resistance. However, since the color is not greenish, the color developability of green superimposed with cyan toner decreases when a release agent is added.

  C. I. Pigment Yellow 180 has high safety and high light resistance, but the color is reddish and the green color develops.

The yellow toner and other color toners used in the dry electrophotographic full-color image forming apparatus used in the present invention will be described.
The toner used in the present invention includes at least a colorant, a binder resin, and a mold release, and has a weight average particle diameter D4 of 2.0 to 8.0 μm.
As colors other than yellow, at least two colors of magenta and cyan are required, and black toner is preferably used for this. In addition to the yellow, magenta, cyan, and black toners, let, blue, and green toners can be added.

Here, as the toner used in the present invention, known resins can be used.
As the binder resin, styrene such as polystyrene, poly-p-chlorostyrene, polyvinyltoluene and the like, and polymers of the substitution products thereof; styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer Polymer, styrene-vinyl naphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methacrylic acid Methyl copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ketone copolymer , Styrene-butadiene copolymer, steel Styrene copolymers such as styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer; polymethyl methacrylate, polybutyl methacrylate, polychlorinated Vinyl, polyvinyl acetate, polyethylene, polypropylene, polyester, epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, aliphatic or alicyclic hydrocarbon resin, Aromatic petroleum resins, chlorinated paraffin, paraffin wax and the like can be mentioned, and these can be used alone or in combination. A polyester resin such as a polycondensed polyester resin can be preferably used, and among them, a polyester resin having a branched structure is more preferably used.

  Although it does not specifically limit as polycondensation polyester resin which comprises the toner binder of this invention, For example, polyepoxide (C) etc. are further added to polyester resin (X) and (X) which are polycondensates of a polyol and polycarboxylic acid. Examples thereof include a modified polyester resin (Y) obtained by reacting. (X), (Y) and the like may be used alone or in combination of two or more.

  Although it does not specifically limit as a polyol, For example, diol (G), a trihydric or more polyol (H), etc. are mentioned. Although it does not specifically limit as polycarboxylic acid, For example, dicarboxylic acid (I), polycarboxylic acid (J) more than trivalence, etc. are mentioned.

  The polyester resin constituting the toner binder of the present invention is not particularly limited, but specific examples include the following, and these can also be used in combination. (X1): Linear polyester resin using (G) and (I) (X2): Non-linear polyester resin using (H) and / or (J) together with (G) and (I) ( Y1): The modified polyester resin diol (G) obtained by reacting (C2) with (X2) is not particularly limited. For example, diols having a hydroxyl value of 180 to 1900 mgKOH / g, specifically, 12 alkylene glycols (such as ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butylene glycol and 1,6-hexanediol); alkylene ether glycols (diethylene glycol, triethylene glycol, dipropylene) Glycol, polyethylene glycol, polypropylene glycol and polybutylene glyco Alicyclic diols (such as 1,4-cyclohexanedimethanol and hydrogenated bisphenol A); bisphenols (such as bisphenol A, bisphenol F, and bisphenol S); Alkylene oxide [ethylene oxide (hereinafter abbreviated as EO), propylene oxide (hereinafter abbreviated as PO), butylene oxide (hereinafter abbreviated as BO), etc.] adduct; , PO, BO, etc.).

Among these, preferred are alkylene glycols having 2 to 12 carbon atoms, alkylene oxide adducts of bisphenols, and combinations thereof, and particularly preferred are alkylene oxide adducts of bisphenols and those having 2 to 2 carbon atoms. Combination with 12 alkylene glycols.
In the above and below, the hydroxyl value and the acid value are measured by the method defined in JIS K 0070.

  The trihydric or higher polyol (H) is not particularly limited. For example, polyols having a hydroxyl value of 150 to 1900 mgKOH / g, specifically, 3 to 8 or higher aliphatic polyhydric alcohols (glycerin, trie Tyrolethane, trimethylolpropane, pentaerythritol, sorbitol, etc.); adducts of the above aliphatic polyhydric alcohols with 2 to 4 carbon oxides (such as EO, PO and BO); trisphenols (such as trisphenol PA) A novolak resin (such as phenol novolak and cresol novolak); an adduct of C 2-4 alkylene oxide (such as EO, PO and BO) of the above trisphenol; a C 2-4 alkylene oxide of the above novolac resin (EO) , PO, BO, etc.) That.

Among these, preferred are aliphatic polyhydric alcohols having 3 to 8 valences or higher and alkylene oxide adducts of novolak resins, and particularly preferred are alkylene oxide adducts of novolak resins.
Although it does not specifically limit as dicarboxylic acid (I), For example, the dicarboxylic acid of acid value 180-1250 mgKOH / g, Specifically, C4-C36 alkylene dicarboxylic acid (succinic acid, adipic acid, sebacic acid, and dodecenyl succinic acid). Acid etc.): C4-C36 alkenylene dicarboxylic acid (maleic acid, fumaric acid, etc.); C8-36 aromatic dicarboxylic acid (phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, etc.) It is done. Of these, preferred are alkenylene dicarboxylic acids having 4 to 20 carbon atoms and aromatic dicarboxylic acids having 8 to 20 carbon atoms. Moreover, even if these use together 2 or more types, there is no problem. As (I), acid anhydrides or lower (1 to 4 carbon atoms) alkyl esters (methyl ester, ethyl ester, isopropyl ester, etc.) described above may be used.

  Although it does not specifically limit as polycarboxylic acid (J) more than trivalence, For example, polycarboxylic acid with an acid value of 150-1250 mgKOH / g, specifically, C9-C20 aromatic polycarboxylic acid (trimerit Acid, pyromellitic acid, etc.); vinyl polymer of unsaturated carboxylic acid (styrene / maleic acid copolymer, styrene / acrylic acid copolymer, α-olefin / maleic acid copolymer, styrene / fumaric acid copolymer) Etc.). Among these, preferred are aromatic polycarboxylic acids having 9 to 20 carbon atoms, and particularly preferred are trimellitic acid and pyromellitic acid. As the trivalent or higher polycarboxylic acid (J), acid anhydrides or lower (1 to 4 carbon atoms) alkyl esters (methyl ester, ethyl ester, isopropyl ester, etc.) described above may be used.

Moreover, hydroxycarboxylic acid (K) can also be copolymerized with (G), (H), (I) and (J).
Although it does not specifically limit as hydroxycarboxylic acid (K), For example, a hydroxy stearic acid, hydrogenated castor oil fatty acid, etc. are mentioned.

Although it does not specifically limit as polyepoxide (C), For example, polyglycidyl ether [ethylene glycol diglycidyl ether, tetramethylene glycol diglycidyl ether, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, glycerin triglycidyl ether, bentaerythritol tetra Glycidyl ether, phenol novolac (average degree of polymerization 3 to 60) glycidyl ether, etc.]; diene oxide (pentadiene dioxide, hexadiene dioxide, etc.) and the like. Among these, polyglycidyl ether is preferable, and ethylene glycol diglycidyl ether and bisphenol A diglycidyl ether are more preferable.
The number of epoxy groups per molecule of (C) is preferably 2-8, more preferably 2-6, and particularly preferably 2-4.

  Although it does not specifically limit as an epoxy equivalent of (C), Preferably it is 50-500. The lower limit is more preferably 70, particularly preferably 80, and the upper limit is more preferably 300, particularly preferably 200. When the number of epoxy groups and / or the epoxy equivalent is within the above range, both developability and fixability are improved. More preferably, the above-mentioned ranges of the number of epoxy groups per molecule and the range of epoxy equivalents are satisfied at the same time.

The ratio of the polyol and the polycarboxylic acid is preferably 2/1 to 1/2, more preferably 1.5 / 1 to 1 as an equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] and the carboxyl group [COOH]. 1 / 1.3, particularly preferably 1.3 / 1-1 / 1.2. The types of polyol and polycarboxylic acid to be used are preferably selected in consideration of molecular weight adjustment so that the glass transition point of the polyester toner binder finally adjusted is 40 to 90 ° C. Although it does not specifically limit as a specific example of (X1), For example, the following (1)-(3) etc. are mentioned.
(1) Bisphenol A · PO2 molar adduct / terephthalic acid polycondensate.
(2) Bisphenol A · EO 4 mol adduct / bisphenol A · PO 2 mol adduct / terephthalic acid polycondensate.
(3) Bisphenol A · PO2 mol adduct / bisphenol A · PO3 mol adduct / terephthalic acid / isophthalic acid / maleic anhydride polycondensate.

Although it does not specifically limit as a specific example of (X2), For example, the following (4)-(10) etc. are mentioned.
(4) Bisphenol A · EO 2 mol adduct / bisphenol A · PO 3 mol adduct / terephthalic acid / phthalic anhydride / trimellitic anhydride polycondensate.
(5) Bisphenol A · PO2 mol adduct / bisphenol A · PO3 mol adduct / bisphenol A · EO2 mol adduct / phenol novolac PO5 mol adduct / terephthalic acid / maleic anhydride / dimethyl terephthalic acid ester / trimellitic anhydride Acid polycondensate.
(6) Bisphenol A · EO 2 mol adduct / bisphenol A · PO 2 mol adduct / terephthalic acid / trimellitic anhydride polycondensate.
(7) Bisphenol A · EO 2 mol adduct / bisphenol A · PO 2 mol adduct / terephthalic acid / maleic anhydride / trimellitic anhydride polycondensate.
(8) Bisphenol A · PO 2 mol adduct / bisphenol A · PO 3 mol adduct / terephthalic acid / isophthalic acid / maleic anhydride / trimellitic anhydride polycondensate.
(9) Bisphenol A • PO2 molar adduct / bisphenol A • P03 molar adduct / phenol novolak EO adduct / isophthalic acid / trimellitic anhydride polycondensate.
(10) Bisphenol A · EO 2 mol adduct / bisphenol A · PO 2 mol adduct / phenol novolak PO5 mol adduct / terephthalic acid / fumaric acid / trimellitic anhydride polycondensate.

Although it does not specifically limit as a specific example of (Y1), For example, the following (11)-(20) etc. are mentioned.
(11) Modification obtained by reacting tetramethylene glycol diglycidyl ether with polycondensate of bisphenol A · PO 2 mol adduct / bisphenol A · EO 2 mol adduct / PO 5 mol adduct of phenol novolac / terephthalic acid / dodecenyl succinic anhydride polyester.
(12) Bisphenol A · PO2 mol adduct / bisphenol A · PO3 mol adduct / bisphenol A · EO2 mol adduct / PO5 mol adduct of phenol novolac / terephthalic acid / dodecenyl succinic anhydride heavy bond ethylene glycol diglycidyl ether Modified polyester obtained by reacting
(13) Reaction of bisphenol A diglycidyl ether with bisphenol A · PO 2 mol adduct / bisphenol A · PO 3 mol adduct / phenol novolak EO adduct / isophthalic acid / maleic anhydride / trimellitic anhydride polycondensate The resulting modified polyester.
(14) Bisphenol A / PO 2 mol adduct / Bisphenol A / PO 3 mol adduct / Bisphenol A / EO 2 mol adduct / EO adduct of phenol novolac / Terephthalic acid / Isophthalic acid / Trimellitic anhydride polycondensate A modified polyester obtained by reacting diglycidyl ether.
(15) Bisphenol A / PO 2 mol adduct / bisphenol A / PO 3 mol adduct / bisphenol A / EO 2 mol adduct / phenol novolak PO5 mol adduct / terephthalic acid / isophthalic acid / maleic anhydride / trimellitic anhydride heavy A modified polyester obtained by reacting a condensate with bisphenol A diglycidyl ether.
(16) A modified polyester obtained by reacting ethylene glycol diglycidyl ether with bisphenol A · PO 3 mol adduct / phenol novolac PO 5 mol adduct / terephthalic acid / fumaric acid / trimellitic anhydride polycondensate.
(17) A modified polyester obtained by reacting tetramethylene glycol diglycidyl ether with a polycondensate of bisphenol A · PO 2 mol adduct / phenol novolac PO 5 mol adduct / terephthalic acid / dodecenyl succinic anhydride / trimellitic anhydride.
(18) Modified polyester obtained by reacting bisphenol A · PO2 molar adduct / bisphenol A · EO2 molar adduct / phenol novolak EO adduct / terephthalic acid / trimellitic anhydride polycondensate with ethylene glycol diglycidyl ether .
(19) Modification obtained by reacting bisphenol A diglycidyl ether with bisphenol A · PO2 mol adduct / bisphenol A · PO3 mol adduct / PO5 mol adduct of phenol novolac / terephthalic acid / trimellitic anhydride polycondensate polyester.
(20) A modified polyester obtained by reacting a phenol novolac glycidyl etherified product with a bisphenol A · PO 2 mol adduct / bisphenol A · EO 2 mol adduct / terephthalic acid / trimellitic anhydride polycondensate.

The toner binder is required to have different physical properties for full color and monochrome use, and the design of the polyester resin is also different.
That is, since a high-gloss image is required for full color use, it is necessary to use a low-viscosity binder. However, for monochrome use, gloss is not particularly required, and hot offset properties are important, so a high-elasticity binder is required. .
(X1), (X2), (Yl) and mixtures thereof are preferred for obtaining a high gloss image useful for a full-color copying machine or the like. In this case, since it is preferable that the viscosity is low, the ratio of (H) and / or (J) constituting these polyester resins is such that the sum of the number of moles of (H) and (J) is (G) to Preferably it is 0-20 mol% with respect to the total number of moles of (J), More preferably, it is 0-15 mol%, Especially 0-10 mol%.

  In the case of a full-color polyester resin, the temperature (TE) at which the complex viscosity becomes 100 Pa · S is preferably 90 to 170 ° C, more preferably 100 to 165 ° C, and particularly 105 to 150 ° C. Sufficient gloss is obtained at 170 ° C. or lower, and heat resistant storage stability is improved at 90 ° C. or higher.

  In order to give the polyester resin a branched structure, the above-mentioned trivalent or higher polyol (H) and trivalent or higher polycarboxylic acid (J) are used in the polyester resin, thereby taking a branched polyester resin structure. Can do.

  The toner of the present invention is premised on use in a fixing machine with a simplified oil application mechanism. At this time, hot offset is less likely to occur if the binder resin has a certain degree of elasticity when heated. Specifically, by giving a branched structure to the molecules of the binder resin, a certain degree of melt viscosity can be given in a heated state.

  As the release agent used in the toner of the present invention, a wax having a melting point of 40 to 120 ° C. is preferable, and a wax having a melting point of 50 to 110 ° C. is particularly preferable. When the melting point of the release agent is higher than 120 ° C., the fixing property at low temperature may be insufficient, while when the melting point is lower than 40 ° C., the offset resistance and durability may be lowered. The melting point of the wax can be obtained by differential scanning calorimetry (DSC). That is, the melting peak value when a sample of several mg is ripened at a constant temperature increase rate, for example, (10 ° C./min) is defined as the melting point.

  Examples of the release agent that can be used in the present invention include solid paraffin wax, microwax, rice wax, fatty acid amide wax, fatty acid wax, aliphatic monoketone, fatty acid metal salt wax, fatty acid ester wax, Examples thereof include partially saponified fatty acid ester waxes, silicone varnishes, higher alcohols, and carnauba waxes. Also, polyolefins such as low molecular weight polyethylene and polypropylene can be used. In particular, in terms of releasability, ester wax or carnauba wax is preferred. In particular, when a polyester resin is used as the binder resin, ester wax and carnauba wax are preferable. Ester wax and carnauba wax are very hard at normal temperature and are advantageous for toner storage. Polyester resin, ester wax, and carnauba wax have some compatibility, and the wax is slightly contained in the binder resin. A toner having good releasability is obtained by dispersing.

The toner used in the present invention may contain a charge control agent, a release agent, and other external additives as necessary.
Known charge control agents can be used, such as nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (fluorine-modified 4 Secondary ammonium salts or compounds, tungsten simple substances or compounds, fluorine activators, salicylic acid metal salts, and metal salts of salicylic acid derivatives. Specifically, Nitronine-based dye Bontron 03, quaternary ammonium salt Bontron P-51, metal-containing azo dye Bontron S-34, oxynaphthoic acid metal complex E-82, salicylic acid metal complex E- 84, E-304, X-11, phenolic condensate E-89 (above, manufactured by Orient Chemical Industries), quaternary ammonium salt molybdenum complex TP-302, TP-415, salicylic acid metal complex TN -105 (above, manufactured by Hodogaya Chemical Co., Ltd.), quaternary ammonium salt copy charge PSY VP2038, triphenylmethane derivative copy blue PR, quaternary ammonium salt copy charge NEG VP2036, copy charge NX VP434 (above , Manufactured by Hoechst), LRA-901, LR-147, a boron complex (Japan) Ritto Ltd.), copper phthalocyanine, perylene, quinacridone, azo pigments, sulfonate group, carboxyl group, and polymer compounds having a functional group such as a quaternary ammonium salt.

  In the present invention, the amount of the charge control agent used for reinforcement is determined by the toner production method including the amount of the electric control agent, the type of binder resin, the presence or absence of additives used as necessary, and the dispersion method. Although it is not limited uniquely, Preferably it is used in 0.1-10 weight part with respect to 100 weight part of binder resin. The range of 0.3 to 5 parts by weight is preferable. When the amount exceeds 10 parts by weight, the chargeability of the toner is too high, the effect of the main charge control agent is reduced, the electrostatic attractive force with the developing roller is increased, the flowability of the developer is reduced, and the image density is reduced. Incurs a decline.

As the external additive used in the toner of the present invention, inorganic fine particles can be preferably used. The primary particle diameter of the inorganic fine particles is preferably 5 mμ to 2 μm, and particularly preferably 5 mμ to 500 mμ. Moreover, it is preferable that the specific surface area by BET method is 20-500 m < ² > / g. The proportion of the inorganic fine particles used is preferably 0.01 to 5% by weight of the toner, and particularly preferably 0.01 to 2.0% by weight.

Specific examples of the inorganic fine particles include silica, titanium oxide, alumina, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, silica sand, clay, mica, wollastonite, and diatomaceous earth. Examples include soil, chromium oxide, cerium oxide, pengala, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride.
In addition, polymer fine particles such as polystyrene, methacrylic acid ester and acrylic acid ester copolymer obtained by soap-free emulsion polymerization, suspension polymerization and dispersion polymerization, polycondensation resin such as silicone resin, benzoguanamine resin and nylon Thermosetting resin polymer particles can also be used.

  Such external additives can be surface-treated to increase hydrophobicity and prevent deterioration of flow characteristics and charging characteristics even under high humidity. For example, a silane coupling agent, a silylating agent, a silane coupling agent having a fluorinated alkyl group, an organic titanate coupling agent, an aluminum coupling agent and the like are preferable surface treatment agents.

  Further, the toner of the present invention can contain a cleaning property improver in order to remove the developer after transfer remaining on the photoreceptor or the primary transfer medium. Examples of such a cleaning property improver include: Examples thereof include fatty acid metal salts such as zinc stearate and calcium stearate, and polymer fine particles produced by soap-free emulsion polymerization such as polymethyl methacrylate fine particles and polystyrene fine particles. The polymer fine particles preferably have a relatively narrow particle size distribution and a volume average particle size of 0.01 to 1 μm.

  The colors of the resin, charge control agent, release agent, and external additive used in the cyan, magenta, and yellow toners of the present invention are preferably colorless and transparent, translucent, white, light translucent, and light. Since the cyan, magenta, and yellow toners of the present invention are required to have high saturation, colors other than the colorant need to be light and difficult to become cloudy.

  As the colorant that can be used in the toner of the present invention, known dyes and pigments can be used. For example, carbon black, nigrosine dye, iron black, and yellow pigment C.I. I. As auxiliary components of Pigment Yellow 185, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, ocher, yellow lead, titanium yellow, polyazo yellow, oil yellow, Hansa yellow (GR , A, RN, R), Pigment Yellow L, Benzidine Yellow (G, GR), Permanent Yellow (NCG), Vulcan Fast Yellow (5G, R), Tartrazine Lake, Quinoline Yellow Lake, Anthrazan Yellow BGL, IsoIndia Rinon Yellow, Bengala, Pangtan, Pepper Red, Cadmium Red, Cadmium Mercury Red, Antimony Zhu, Permanent Red 4R, Para Red, Faise Red, Parachlor Ortho Nitroaniline Red, Resol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmine BS, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Velcan Fast Rubin B, Brilliant Scarlet G, Resol Rubin GX, Permanent Red F5R, Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Toluidine Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thioindigo Red B, Thioindigo maroon, oil red, quinacridone red, pyrazolone red, polyazo red, chrome vermilion, benzigi Orange, Perinone Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkaline Blue Lake, Peacock Blue Lake, Victoria Blue Lake, Metal Free Phthalocyanine Blue, Phthalocyanine Blue, Fast Sky Blue, Indanthrene Blue (RS, BC), Indigo , Ultramarine, bitumen, anthraquinone blue, fast violet B, methyl violet lake, cobalt purple, manganese purple, dioxane violet, anthraquinone violet, chrome green, zinc green, chromium oxide, pyridiane, emerald green, pigment green B, naphthol green B, Green Gold, Acid Green Lake, Malachite Green Lake, Phthalocyanine Green, Anthraquinone Green, Acid Titanium, zinc white, lithopone and mixtures thereof can be used. The amount used is generally 0.1 to 50 parts by weight per 100 parts by weight of the binder resin. In the present invention, these colorants are used alone, or two or more colorants are mixed to adjust the color of the toner of the present invention. Among the above colorants, yellow pigment C.I. I. Pigment Yellow 185's auxiliary yellow colorant is C.I. I. It can be used in the range of 0 to 100% by weight with respect to Pigment Yellow 185.

  Examples of the colorant for cyan toner include C.I. I. Pigment Blue 15, C.I. I. Pigment Blue 15-1, C.I. I. Pigment Blue 15-2, C.I. I. Pigment Blue 15-3, C.I. I. Pigment Blue 15-4 and the like are preferable.

  The colorant of magenta toner is C.I. I. Pigment Red 57-1, C.I. I. Pigment Violet 19, C.I. I. Pigment Red 122, C.I. I. Pigment Red 146, C.I. I. Pigment Red 147, C.I. I. Pigment Red 176, C.I. I. Pigment Red 184, C.I. I. Pigment Red 185, C.I. I. Pigment Red 269 and the like.

  As the black toner colorant, carbon black, iron oxide, metal oxide, oxide composite metal and the like are preferable. In particular, carbon black is preferable. However, when it is thin, the color changes from red to yellow. Therefore, if necessary, other complementary colorants such as a cyan pigment can be used.

  In the present invention, C.I. I. Pigment Yellow 185 is used as a pigment for yellow toner. By using pigments with high light resistance for cyan and magenta, an image having good storage stability can be obtained even outdoors. Specifically, cyan is C.I. I. Pigment Blue 15-3, magenta is C.I. I. Pigment Violet 19 or C.I. I. By using Pigment Red 122, a full-color image with high light resistance can be obtained.

When pigments are used as colorants for cyan, yellow, and magenta toners, when the pigments aggregate in the toner or the pigment particle size is 200 nm or more, the toner becomes opaque and the saturation of the image decreases. In the color development of the image by toner, light passes through the toner layer and is reflected on the paper, and light passes through the toner layer and enters the eye. At this time, when light passes through the toner layer or the ink layer, it absorbs a specific absorption wavelength and transmits light of a specific non-absorption wavelength, so that a color of the non-absorption wavelength is developed. At this time, if the pigment particles are large or the pigment is agglomerated, light up to a specific non-absorption wavelength is absorbed or diffusely reflected, and the light at the non-absorption wavelength is weakened, and the color saturation is lowered. Therefore, in the present invention, it is preferable to disperse the pigment in a binder resin (binder resin) in the toner and knead and disperse the primary particle diameter of the pigment to 200 nm or less, and further to 150 nm or less.
In particular, it is preferable to use a pigment having a primary particle diameter of 30 to 120 nm.

The present invention is characterized in that a master batch kneaded in advance with 1 to 4 parts by weight of a resin with respect to 2 parts by weight of a colorant is used to increase the dispersion of the pigment. By kneading the pigment with a small amount of resin, it is possible to disperse the pigment under conditions that enable high dispersion that cannot be obtained during toner preparation. By kneading the pigment with a small amount of resin, the viscosity increases, the shearing force applied to the pigment itself can be increased, and the aggregated pigments can be separated. In addition, the viscosity of the resin can be adjusted to the optimum condition by adjusting the kneading temperature so that a shearing force is applied. When kneading with 1 to 4 parts by weight of resin with respect to 2 parts by weight of the colorant in advance, an organic solvent such as acetone, toluene or MEK or water may be added as necessary to aid dispersion. Absent. Moreover, you may use dispersing agents, such as surfactant, as needed.
As the disperser, existing ones such as a two-roll, a three-roll, a flushing device, a biaxial continuous kneader, and a monoaxial continuous kneader can be used.
When a highly dispersed master batch is used, since the pigment is dispersed in advance with a resin, the pigment is easily dispersed in the toner binder resin, and a toner having high transparency and good color development can be obtained.

The measurement method of the image density and the color tone characteristic of the image in the present invention was performed in status-A using X-Rite 938 manufactured by X-Rite.
Further, the glossiness was measured using a Murakami glossiness meter TAPPI T480 om-90 under the condition of 60 degrees.

The toner particle size of the present invention was measured by a Coulter counter method.
As an apparatus for measuring the particle size distribution of toner particles by the Coulter counter method, there are Coulter Counter TA-II and Coulter Multisizer II (both manufactured by Coulter). The measurement method is described below.
First, 0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 ml of the electrolytic aqueous solution. Here, the electrolytic solution is an about 1% NaCl aqueous solution prepared using sodium chloride, and for example, ISOTON-II (manufactured by Coulter) can be used. Here, 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes. Volume distribution and number distribution are calculated.

  In full-color image formation using an electrophotographic system, it is necessary to use four color toners of black, yellow, magenta, and cyan, and to superimpose the four color toners on paper, sheets, and the like that are final image carriers. The following two methods are mainly used as a method of superposing four color toners.

First, the latent image on the electrostatic latent image holding member is developed for each color with black, yellow, magenta, and cyan toners, and toner is transferred from the electrostatic latent image holding member to the final image holding member in order of each color. This is a method of transferring and superimposing four color toners directly on the final image holding member (hereinafter referred to as a direct transfer method).
Second, the latent image on the electrostatic latent image holding member is developed for each color with toner of four colors, black, yellow, magenta, and cyan, and the toner is transferred from the electrostatic latent image holding member to the intermediate image holding member in order of each color. In this method, four color toner images are superimposed on the intermediate image holding member, and the image is transferred from the intermediate image holding member to the final image holding member (hereinafter referred to as an intermediate transfer method).
In both the above methods, the toner on the final image carrier is fixed to the final image carrier by heat or pressure.

In the direct transfer method, a method using a separate electrostatic latent image carrier for each color or a sequential development with four color toners using one electrostatic latent image carrier and fixing the final image carrier to a cylinder or the like. There is a method of transferring the final image carrier. In addition, the method using a separate electrostatic latent image holding member for each color enables high-speed output. Since each of the latent image holding bodies has four colors, it is necessary to control color misregistration when four colors are superimposed. In particular, since the main body of the image forming machine is deformed by thermal expansion, color misregistration correction is generally performed at a certain interval.
Further, the method of developing sequentially with four color toners using one electrostatic latent image holding member, fixing the final image holding member to a hard cylinder or the like, and transferring the final image holding member has high accuracy with respect to color misregistration. Since the final image holding body is fixed to a cylinder or the like, there are many restrictions on the shape, size, rigidity, etc. of the final image holding body. Further, since the machine has a cylinder or the like for fixing the final image holder, the mechanism becomes complicated.

In the intermediate transfer method, a method in which a single electrostatic latent image holding member is used, sequentially developed with four color toners, and transferred onto the intermediate image holding member is often used. This method has high accuracy with respect to color misregistration, and if a belt or the like is used for the image intermediate holding member, the machine layout has a higher degree of freedom.
Further, in the intermediate transfer method, there is a method in which an electrostatic latent image holding member is used for each of four colors, transferred onto the intermediate image holding member, and transferred to the final image holding member. This method also enables high-speed output. However, as with the direct transfer method, color misregistration is likely to occur, and color misregistration is generally corrected.
In the intermediate transfer method, since the image is transferred twice, the possibility that the image is disturbed is higher than that in the direct transfer method.
However, in order to obtain a full color image by any method, toner is transferred from the electrostatic latent image holding member to the final image holding member or from the electrostatic latent image holding member onto the intermediate image holding member, and the four color toners are transferred. Need to be stacked.

The toner developing method for the photoreceptor is roughly divided into a one-component method and a two-component method, but any method may be used in the present invention.
FIG. 1 shows an example of an image forming apparatus of the present invention. In FIG. 1, a printer main body (910) includes an image writing unit (912), an image forming unit (913), and a paper feeding unit (914) for performing color image formation by electrophotography. Based on the image signal, the image processing unit converts the image into black (BK), magenta (M), yellow (Y), and cyan (C) color signals for image formation, and an image writing unit (912). Send to. The image writing unit (912) is, for example, a laser scanning optical system including a laser light source, a deflector such as a rotating polygon mirror, a scanning imaging optical system, and a mirror group. The image writing unit (912) corresponds to each color signal described above. There are two writing optical paths, and image carriers (photoconductors) (921BK), (921M), (921Y), and (921C) provided for the respective colors of the image forming unit (913) correspond to the respective color signals. Perform image writing.

  The image forming unit (913) is a photoconductor (921BK), (921M), (921Y) which is an image carrier for black (BK), magenta (M), yellow (Y), and cyan (C). ), (921C). As each photoconductor for each color, an OPC photoconductor is usually used. Around each of the photosensitive members (921BK), (921M), (921Y), and (921C), there are a charging device, a laser beam exposure unit from the writing unit (912), and each color of black, magenta, yellow, and cyan Developing devices (920BK), (920M), (920Y), (920C), primary transfer bias rollers (923BK), (923M), (923Y), (923C), a cleaning device (primary transfer means) (Not shown), and a photosensitive member neutralizing device (not shown) are provided. The developing devices (920BK), (920M), (920Y), and (920C) use a two-component magnetic brush developing system. The intermediate transfer belt (922), which is a belt component, includes the photosensitive members (921BK), (921M), (921Y), and (921C), and the primary transfer bias rollers (923BK), (923M), and (923Y). , (923C), and the toner images of the respective colors formed on the respective photoreceptors are sequentially superimposed and transferred.

  On the other hand, the transfer paper (P) is fed from the paper feeding section (914) and then carried on the transfer conveyance belt (950), which is a belt constituent section, via the registration rollers (916). When the intermediate transfer belt (922) and the transfer conveyance belt (950) come into contact with each other, the toner image transferred onto the intermediate transfer belt (922) becomes a secondary transfer bias roller (960) as a secondary transfer unit. ) For secondary transfer (collective transfer). Thereby, a color image is formed on the transfer paper (P). The transfer paper (P) on which the color image is formed is conveyed to the fixing device (915) by the transfer conveyance belt (950), and after the image transferred by the fixing device (915) is fixed, the transfer paper (P) To be discharged.

  The residual toner that is not transferred during the secondary transfer and remains on the intermediate transfer belt (922) is removed from the intermediate transfer belt (922) by the belt cleaning device (925). A lubricant application device (not shown) is disposed on the downstream side of the belt cleaning device (925). This lubricant application device includes a solid lubricant and a conductive brush that rubs the intermediate transfer belt (922) to apply the solid lubricant. The conductive brush is always in contact with the intermediate transfer belt (922) and applies a solid lubricant to the intermediate transfer belt (922). The solid lubricant has an effect of improving the cleaning property of the intermediate transfer belt (922), preventing the occurrence of filming and improving the durability.

  The seamless belt according to the present invention can be suitably applied to an intermediate transfer belt type image forming apparatus equipped with the intermediate transfer belt (922) as described above, and a transfer conveyance belt instead of the intermediate transfer belt (922). The present invention can also be applied to a transfer / conveying belt type image forming apparatus equipped with the above. Further, in the case of an image forming apparatus using a transfer / conveying belt system, the present invention can be applied to either the 1-photosensitive drum system or the 4-photosensitive drum system.

Hereinafter, the present invention will be described by way of examples.
These examples are merely examples of the present invention, and the present invention is not limited to these examples.
The following polyester resin A was prepared by synthesizing bisphenol A ethylene oxide adduct, bisphenol A propylene oxide adduct, terephthalic acid, and fumaric acid in a molar ratio of 1: 1: 1: 1. The number average molecular weight was 2400, the weight average molecular weight was 11,000, and Tg was 63 ° C.
Polyester resin B was synthesized from bisphenol A ethylene oxide adduct, bisphenol A propylene oxide adduct, terephthalic acid, fumaric acid and trimellitic acid in a molar ratio of 1: 1: 0.85: 0.85: 0.2. It was used. The number average molecular weight was 2500, the weight average molecular weight was 290000, and Tg was 65 ° C.

Example 1
Yellow toner prescription:
Polyester resin A 70 parts by weight Polyester resin B 40 parts by weight C.I. I. Pigment Yellow 185 8 parts by weight (Paliotol Yellow D1155 manufactured by BASF Japan)
Carnauba wax 5 parts by weight (WA-03 manufactured by Toa Kasei)
Magenta toner prescription:
Polyester resin A 70 parts by weight Polyester resin B 40 parts by weight C.I. I. Pigment Red 122 8 parts by weight (manufactured by Clariant Japan, PV Fast Pink E)
Carnauba wax 5 parts by weight (WA-03 manufactured by Toa Kasei)
Cyan toner prescription:
Polyester resin A 70 parts by weight Polyester resin B 40 parts by weight C.I. I. Pigment Blue 15-3 4 parts by weight (Toner Cyan BG manufactured by Clariant Japan)
Carnauba wax 5 parts by weight (WA-03 manufactured by Toa Kasei)
Black toner prescription:
Polyester resin A 70 parts by weight Polyester resin B 40 parts by weight Carbon black 6 parts by weight (Mitsubishi Chemical Corporation Mitsubishi Carbon Black # 44)
Carnauba wax 5 parts (WA-03 manufactured by Toa Kasei)

Among the above materials, the pigment, polyester resin A and pure water were mixed at a ratio of 1: 1: 0.5 and kneaded by two rolls. Kneading was performed at 70 ° C., and then the roll temperature was raised to 120 ° C. and kneading was continued until water was evaporated to prepare a master batch in advance.
Using the prepared master batch, the materials were mixed in the same way as the above recipe, melted and kneaded with two rolls, cooled, coarsely pulverized with a hammer mill, and finely pulverized with an air jet pulverizer. Fine powders were classified to prepare four-color powders having a weight average particle diameter (D4) of 7 μm. 100 parts by weight of the fine powder, 1 part by weight of silica (HDK-H200, manufactured by Clariant Japan) and 1 part by weight of titanium oxide (SMT-150AI, manufactured by Taika) were mixed to obtain a toner of four colors.

Example 2
Yellow toner prescription:
Polyester resin A 100 parts by weight C.I. I. Pigment Yellow 185 12 parts by weight (PALIOTOL Yellow D1155 manufactured by BASF Japan)
Ester wax 5 parts by weight (Nippon Yushi Co., Ltd. WEP-3)
Magenta toner prescription:
Polyester resin A 100 parts by weight C.I. I. Pigment Red 122 12 parts by weight (PV Fast Pink E manufactured by Clariant Japan)
Ester wax 5 parts by weight (Nippon Yushi Co., Ltd. WEP-3)
Cyan toner prescription:
Polyester resin A 100 parts by weight C.I. I. Pigment Blue 15-3 6 parts by weight (Toner Cyan BG manufactured by Clariant Japan)
Ester wax 5 parts by weight (Nippon Yushi Co., Ltd. WEP-3)
Black toner prescription:
Polyester resin A 100 parts by weight Carbon black 8 parts by weight (Mitsubishi Chemical Corporation Mitsubishi Carbon Black # 44)
Ester wax 5 parts by weight (Nippon Yushi Co., Ltd. WEP-3)

Among the above materials, the pigment, polyester resin A and pure water were mixed at a ratio of 1: 1: 0.5 and kneaded by two rolls. Kneading was performed at 70 ° C., and then the roll temperature was raised to 120 ° C. and kneading was continued until water was evaporated to prepare a master batch in advance.
Using the prepared master batch, the materials were mixed in the same way as the above recipe, melted and kneaded with two rolls, cooled, coarsely pulverized with a hammer mill, and finely pulverized with an air jet pulverizer. Fine powders were classified to prepare four-color powders having a weight average particle diameter (D4) of 5 μm. 100 parts by weight of the fine powder, 1.5 parts by weight of silica (HDK-H200 manufactured by Clariant Japan), and 1.5 parts by weight of titanium oxide (SMT-150AI manufactured by Teika) were mixed to obtain a toner of four colors. . For reference, most of the weight average particle diameters of the pigments used in the above examples are around 100 nm.

Comparative Examples 1-6
The yellow toner pigment of Example 1 was changed in weight part from the pigments shown in the following table to obtain toner combinations of four colors of Comparative Examples 1-6.

Comparative Example 7
Yellow toner prescription:
Polyester resin A 70 parts by weight Polyester resin B 40 parts by weight C.I. I. Pigment Yellow 185 4 parts by weight (PALIOTOL Yellow D1155 manufactured by BASF Japan)
Carnauba wax 5 parts by weight (WA-03 manufactured by Toa Kasei)
Magenta toner prescription:
Polyester resin A 70 parts by weight Polyester resin B 40 parts by weight C.I. I. Pigment Red 122 4 parts by weight (manufactured by Clariant Japan, PV Fast Pink E)
Carnauba wax 5 parts by weight (WA-03 manufactured by Toa Kasei)
Cyan toner prescription:
Polyester resin A 70 parts by weight Polyester resin B 40 parts by weight C.I. I. Pigment Blue 15-3 2 parts by weight (Toner Cyan BG manufactured by Clariant Japan)
Carnauba wax 5 parts by weight (WA-03 manufactured by Toa Kasei)
Black toner prescription:
Polyester resin A 70 parts by weight Polyester resin B 40 parts by weight Carbon black 3 parts by weight (Mitsubishi Chemical Corporation Mitsubishi Carbon Black # 44)
Carnauba wax 5 parts (WA-03 manufactured by Toa Kasei)

Among the above materials, the pigment, polyester resin A and pure water were mixed at a ratio of 1: 1: 0.5 and kneaded by two rolls. Kneading was performed at 70 ° C., and then the roll temperature was raised to 120 ° C. and kneading was continued until water was evaporated to prepare a master batch in advance.
Using the prepared master batch, the materials were mixed in the same way as the above recipe, melted and kneaded with two rolls, cooled, coarsely pulverized with a hammer mill, and finely pulverized with an air jet pulverizer. Fine powders were classified to prepare four-color powders having a weight average particle diameter (D4) of 9 μm. 100 parts by weight of the fine powder, 0.7 parts by weight of silica (HDK-H200 manufactured by Clariant Japan) and 0.7 parts by weight of titanium oxide (SMT-150AI manufactured by Teika) were mixed to obtain a toner of four colors. .

Comparative Examples 8-9
The yellow toner pigment of Comparative Example 7 was changed in weight part from the pigments shown in the following table to obtain toner combinations of four colors of Comparative Examples 8-9.

Comparative Example 10
Yellow toner prescription:
Polyester resin A 70 parts by weight Polyester resin B 40 parts by weight C.I. I. Pigment Yellow 185 4 parts by weight (PALIOTOL Yellow D1155 manufactured by BASF Japan)
Carnauba wax 5 parts by weight (WA-03 manufactured by Toa Kasei)
Magenta toner prescription:
Polyester resin A 70 parts by weight Polyester resin B 40 parts by weight C.I. I. Pigment Red 122 4 parts by weight (manufactured by Clariant Japan, PV Fast Pink E)
Carnauba wax 5 parts by weight (WA-03 manufactured by Toa Kasei)

Cyan toner prescription:
Polyester resin A 70 parts by weight Polyester resin B 40 parts by weight C.I. I. Pigment Blue 15-3 2 parts by weight (Toner Cyan BG manufactured by Clariant Japan)
Carnauba wax 5 parts by weight (WA-03 manufactured by Toa Kasei)
Black toner prescription:
Polyester resin A 70 parts by weight Polyester resin B 40 parts by weight Carbon black 3 parts by weight (Mitsubishi Chemical Corporation Mitsubishi Carbon Black # 44)
Carnauba wax 5 parts (WA-03 manufactured by Toa Kasei)

Among the above materials, the pigment, polyester resin A and pure water were mixed at a ratio of 1: 1: 0.5 and kneaded by two rolls. Kneading was performed at 70 ° C., and then the roll temperature was raised to 120 ° C. to evaporate water and prepare a master batch in advance.
Using the prepared master batch, the materials were mixed in the same way as the above recipe, melted and kneaded with two rolls, cooled, coarsely pulverized with a hammer mill, and finely pulverized with an air jet pulverizer. Fine powders were classified to prepare four-color powders having a weight average particle diameter (D4) of 7 μm. 100 parts by weight of the fine powder, 1 part by weight of silica (HDK-H200, manufactured by Clariant Japan) and 1 part by weight of titanium oxide (SMT-150AI, manufactured by Taika) were mixed to obtain a toner of four colors.

The toners of Examples 1 and 2 and Comparative Examples 1 to 10 were evaluated by putting them in a Ricoh digital color copying machine imagio Neo C385 which was modified to an oilless fixing machine in which the belt and rollers of the fixing unit were PFA coated.
For the yellow toner images of Examples 1 and 2 and Comparative Examples 1 to 10, the adhesion amount was changed, and the toner adhesion amount at which the image density was 1.3 was confirmed. The results are shown in the following table.

デジタルカラー複写機をイエロー、マゼンタ、シアン、ブラックの最高画像濃度が１．５となるように、トナー付着量を調整した。

The toner adhesion amount was adjusted so that the maximum image density of yellow, magenta, cyan, and black was 1.5 in the digital color copying machine.

Evaluation of single color yellow image A yellow color single color was obtained from a digital color copying machine via a printer controller. The image was measured for L *, C *, and H * using an X-Rite 938 manufactured by X-Rite. The color measurement conditions were a D50 light source and a 2-degree visual field. If L * and C * are large values, the color is bright and vivid, and the color reproduction range is widened.

Green Image Evaluation A single green image was obtained from a digital color copier via a printer controller. A green image is an image in which cyan toner and yellow toner overlap. The image was measured for L *, C *, and H * using an X-Rite 938 manufactured by X-Rite. The color measurement conditions were a D50 light source and a 2-degree visual field. If L * and C * are large values, the color is bright and vivid, and the color reproduction range is widened.

Character Chile Evaluation Green and let characters were output from a digital color copier via a printer controller. The character is “Kanji”. The toner splatter in the character part was evaluated. The case where no toner splattered was marked with ◯, and the case where toner splattered was marked with x.

Resolution confirmation A JIS / JIS-SCID N2 image was output from a digital color copying machine via a printer controller. The case where the image was finely seen up to the image details was marked with ○, and the case where the image details were broken was marked with ×.

Evaluation of Light Resistance A JIS / JIS-SCID N2 image was output to a white film from a digital color copying machine via a printer controller. Samples were exposed for 3 months outdoors in direct sunlight. An image in which the image was not faded was indicated by ◯, and an image in which the yellow color was faded was indicated by ×.
The results are shown in the table below.

  The toners of Example 1 and Example 2 have a large value of the L * and C * values of the yellow image and the L * and C * values of the green image and a wide color reproduction range as compared with the toners of Comparative Examples 1 to 10. Furthermore, it is excellent in terms of dust, resolution, and light resistance.

1 is a diagram illustrating an example of an image forming apparatus of the present invention.

Explanation of symbols

910 Printer main body 912 Image writing unit 913 Image forming unit 914 Paper feeding unit 915 Fixing device 916 Registration roller 920BK, 920M, 920Y, 920C Developing device 921BK, 921M, 921Y, 921C Photoconductor 922 Intermediate transfer belt 923BK, 923M, 923Y, 923C Primary transfer bias roller 925 Belt cleaning device 950 Transfer conveyance belt 960 Secondary transfer bias roller

Claims (7)

A yellow toner used in a dry electrophotographic full-color image forming apparatus, wherein the toner includes at least C.I. I. Pigment Yellow 185, a binder resin, a release agent, a weight average particle diameter D4 of 2.0 to 8.0 μm, and a toner adhesion amount of 0.1 to 0.5 mg / cm for producing a yellow image density of 1.3 A yellow toner characterized by being in the range of ² . 2. The weight average particle diameter D4 is 3.0 to 6.0 μm, and the toner adhesion amount for producing a yellow image density of 1.3 is in the range of 0.1 to 0.4 mg / cm ^2. The yellow toner described in 1. C. in the toner. I. The yellow toner according to claim 1, wherein the amount of Pigment Yellow 185 is 5 to 30% by weight. The yellow toner according to claim 1, wherein the binder resin has a branched structure. 5. The yellow toner according to claim 1, wherein a main component of the binder resin is a polyester resin, and a main component of the release agent is an ester wax or a carnauba wax. A dry electrophotographic full-color image forming apparatus using the yellow toner according to claim 1. A yellow toner according to claim 1, C.I. I. A cyan toner containing CI Pigment Blue 15-3 as a main component of a colorant; I. Pigment Red 122 or C.I. I. A dry electrophotographic full-color image forming apparatus using magenta as a main component of a pigment violet 19 as a main component of a colorant.

Images