JP4784519B2 - Electrophotographic toner, electrophotographic developer, process cartridge, and image forming apparatus - Google Patents

Description

  The present invention relates to an electrophotographic toner, an electrophotographic developer, a process cartridge, and an image forming apparatus that are used for electrophotographic image formation. More specifically, the present invention relates to an electrophotographic toner for photofixing that fixes to a recording sheet with light, an electrophotographic developer, a process cartridge, and an image forming apparatus.

  Conventionally, as an electrophotographic method, an image carrier (sometimes referred to as “photoconductive insulator”, “photoreceptor drum”, etc.) is given an electrostatic charge by a charging means and irradiated with a light image by an exposure means. Then, an electrostatic latent image is formed on the electrostatic latent image carrier, and then the electrostatic latent image is developed using a toner to form a visible image, and the visible image is formed by a transfer unit. A method of obtaining a printed matter by transferring a visual image onto a recording medium such as paper (sometimes referred to as “transfer material” or the like) to form a transfer image, and then fixing the transfer image onto the transfer material by a fixing unit. Generally known.

  At the time of the fixing, the toner constituting the transfer image transferred onto the recording medium is melted by pressurization, heating, solvent vapor, light, etc. and fixed to the recording medium. Here, the light fixing method in which the toner particles are instantaneously irradiated with strong light to melt the toner is superior to other fixing methods for the following reasons. That is, in the case of the optical fixing method, (1) since fixing is performed in a non-contact manner with the toner on the recording medium, bleeding and dust are hardly generated in the fixing process, and resolution is not easily deteriorated. In addition, (2) a quick start is possible with less waiting time after the image forming apparatus is powered on. (3) Even if the transfer material is sandwiched in the fixing device due to a system down or the like, problems such as smoke and fire do not occur. (4) Fixing can be performed regardless of the material and thickness of the transfer material, such as glued paper, preprinted paper, and paper having different thicknesses.

  In recent years, a flash fixing method using a xenon flash lamp as a light source has become common among the light fixing methods. In the flash fixing method, the toner is fixed to the transfer material as follows. That is, first, a visible image by the toner is transferred from a photosensitive drum or the like onto the transfer material to form a transfer image. At the time of this transfer, the transfer image by the toner is only adhered to the transfer material as a powder image. Therefore, if the transfer image is rubbed with a finger, the transfer image is destroyed. Next, the transfer image is irradiated with flash light such as xenon flash. Then, the toner particles constituting the transfer image absorb and increase the temperature of the light energy of the flash light, and are softened and fixed to the transfer material. When the temperature is lowered after the flash irradiation, the transfer image on the transfer material is melted and solidified to form a fixed image.

  In the light fixing method, a xenon flash lamp generally used has a light emission distribution over a wide region from ultraviolet to infrared as shown in FIG. In particular, since the emission intensity is strong in the near infrared region of 800 to 1000 nm, in order to obtain a toner having high fixing performance, a technique for efficiently absorbing light energy in this region is required. In recent years, demand for color prints has increased, but colorants used in color toners often have low light absorption efficiency in the near infrared region, although they absorb in the visible light region. For this reason, development of a color toner capable of obtaining good fixability by the light fixing method is desired.

  Therefore, conventionally, it has been proposed to use a compound having a light absorption ability in the near-infrared region as an infrared absorber and to contain it in the toner. For example, in the techniques of Patent Documents 1 to 3, examples of compounds having light absorption capability in the near infrared region include aminium salts, indium oxide-based metal oxides, tin oxide-based metal oxides, and zinc oxide-based metals. It has been proposed that oxides, cadmium stannate, specific amide compounds, etc. are used as infrared absorbers, and these are contained in the toner to enhance the flash light absorption capability.

However, many of the infrared absorbers are colored, and using them may affect the color tone and color developability of the toner. In the case of the photofixing method, fixing is performed by instantaneously applying high energy to the toner, but since the surface temperature of the toner at the moment when the high energy is applied rises to around 500 ° C., the pigment in the toner In some cases, the components are decomposed, printing defects such as bleeding occur due to the generation of sublimation components, and the hue changes. Moreover, as seen in Patent Document 4, high color development and excellent sublimation resistance are incompatible with each other, and a technique that can achieve both at a high level has been strongly desired. According to the technique of Patent Document 4, although high color developability and sublimation resistance can be obtained by adding a specific pigment to the toner in order to obtain high color developability and sublimation resistance, the charging stability is inferior. In some cases, the fixability and dot fixability during halftone image formation are poor.
JP-A-7-191492 Japanese Patent Laid-Open No. 10-39535 JP-A-11-65167 JP 2003-270861 A

  The present invention is an electrophotographic toner that is excellent in color development and sublimation resistance, and has excellent charging stability, halftone image fixability, and dot fixability, and an electrophotographic developer containing the electrophotographic toner, It is an object of the present invention to provide a process cartridge using the electrophotographic toner and an image forming apparatus using the electrophotographic toner.

The above-mentioned subject is achieved by the following present invention. That is,
The invention according to claim 1 includes at least a binder resin, C.I. Pigment Yellow 111, C.I. Pigment Yellow 180 and C.I. An electrophotographic toner comprising at least one of I pigment yellow 185.

  The invention according to claim 2 provides C.I. I pigment yellow 111 is contained in an amount of 1 to 10% by weight, and C.I. I Pigment Yellow 180 in an amount of 1% by mass to 5% by mass or C.I. 2. The electrophotographic toner according to claim 1, wherein I pigment yellow 185 is contained in an amount of 1% by mass or more and 2% by mass or less.

  The invention according to claim 3 is a C.I. Pigment Yellow 111, C.I. Pigment Yellow 180 and C.I. 3. The electrophotographic toner according to claim 1, wherein the total content of at least one of I pigment yellow 185 is 5% by mass or more and 15% by mass or less.

  The invention according to claim 4 is the toner for electrophotography according to any one of claims 1 to 3, which is a positively chargeable toner.

  The invention according to claim 5 comprises the electrophotographic toner according to any one of claims 1 to 4 and a carrier having a coating layer containing at least a silicone resin on the surface of the core material. It is an electrophotographic developer.

  The invention according to claim 6 is the developer according to claim 5, wherein the silicone resin contained in the coating layer contains 50 mol% or more and 90 mol% or less of dimethylsiloxane as a constituent component.

  According to a seventh aspect of the present invention, there is provided at least developing means for developing an electrostatic latent image formed on the surface of the image carrier with the electrophotographic developer according to the fifth or sixth aspect to form a visible image. A process cartridge is provided.

According to an eighth aspect of the present invention, there is provided an image carrier, a charging unit for charging the surface of the image carrier, a latent image forming unit for forming an electrostatic latent image on the surface of the image carrier charged by the charging unit, Developing means for developing the electrostatic latent image with the electrophotographic developer according to claim 5 or 6 to form a visible image; transfer means for transferring the visible image to a member to be transferred; An irradiating means for irradiating light to the visible image transferred to the member to be transferred includes light having a light emission energy of ⁴ J / cm ² or more from the irradiating means to fix the visible image to the member to be transferred. And an image forming apparatus characterized by comprising a fixing unit.

  According to the present invention, an electrophotographic toner excellent in color development and sublimation resistance, charging stability, halftone image fixability, and dot fixability, and electrophotographic development including the electrophotographic toner It is possible to provide an agent, a process cartridge using the electrophotographic toner, and an image forming apparatus using the electrophotographic toner.

Hereinafter, the present invention will be described in detail.
<Toner for electrophotography>
The electrophotographic toner of the present embodiment includes at least a binder resin, C.I. Pigment Yellow 111, C.I. Pigment Yellow 180 and C.I. And at least one of I Pigment Yellow 185.

  In the present embodiment, the electrophotographic toner is prepared as described above using C.I. Pigment Yellow 111, C.I. Pigment Yellow 180 and C.I. By including at least one of I pigment yellow 185, it has excellent color development and sublimation resistance, charging stability, fixability of halftone images using the electrophotographic toner, and dot fixing. It was found that excellent characteristics can be obtained.

C. in the electrophotographic toner. I pigment yellow 111 is a yellow pigment excellent in color development.
C. above. There is no restriction | limiting in particular as content of I pigment yellow 111, Although it can select suitably according to the objective, It is preferable that it is 1 mass% or more and 10 mass% or less in the whole amount of electrophotographic toner components. More preferably, the content is 1% by mass or more and 4% by mass or less. If this content exceeds 10% by mass, color reproducibility may not be sufficient. On the other hand, when the content is less than 1% by mass, there may be a case where density unevenness or a color reproduction range is narrowed due to insufficient color development.

In addition, C.I. Pigment Yellow 180 and C.I. I pigment yellow 185 is a yellow pigment excellent in heat decomposition resistance and sublimation resistance.
C. There is no restriction | limiting in particular as content of I pigment yellow 180, Although it can select suitably according to the objective, It is preferable that it is 1 mass% or more and 5 mass% or less in the total amount of a toner component, 1 mass. % To 4% by mass is more preferable. This C.I. When the content of I pigment yellow 180 exceeds 5% by mass, the dispersibility of the raw material is deteriorated, so that the saturation of an image formed using this electrophotographic toner may be lowered. In addition, this C.I. When the content of I pigment yellow 180 is less than 1% by mass, there may be a case where density unevenness or a color reproduction range is reduced due to insufficient color development.

  C. There is no restriction | limiting in particular as content of I pigment yellow 185, Although it can select suitably according to the objective, It is 0.5 mass% or more and 2 mass% or less in the whole amount of electrophotographic toner components. Is preferable, and it is more preferable that they are 1 mass% or more and 2 mass% or less. This C.I. By making the content of I pigment yellow 185 within the range of 1% by mass or more and 2% by mass or less, the color development property and the sublimation resistance of the toner for electrophotography are realized, and the change in the charging property during continuous printing is suppressed. It can be realized with a good balance.

  Note that the toner for electrophotography is the above C.I. Pigment Yellow 180 and C.I. In the case of a configuration including both of I pigment yellow 185, C.I. Pigment Yellow 180 and C.I. The total content of I Pigment Yellow 185 is preferably 1% by mass or more and 5% by mass or less, and more preferably 3% by mass or more and 4% by mass or less, based on the total amount of the electrophotographic toner constituent components.

The above-described C.I. Pigment Yellow 111, C.I. Pigment Yellow 180 and C.I. The total content of I pigment yellow 185 is preferably 5% by mass to 15% by mass, more preferably 5% by mass to 11% by mass, and particularly preferably 5% by mass to 7% by mass.
The above-mentioned C.I. Pigment Yellow 111, C.I. Pigment Yellow 180 and C.I. If the total content with I Pigment Yellow 185 exceeds 15% by mass, it may be difficult to obtain both color development and sublimation resistance. If the total content is less than 5% by mass, there may be a case where density unevenness or a color reproduction range is reduced due to insufficient color development.

The above-described C.I. Pigment Yellow 111, C.I. Pigment Yellow 180 and C.I. Since I Pigment Yellow 185 has little variation in hue angle due to the mixing ratio of these pigments, color reproducibility of the primary color Y (yellow) toner that is an electrophotographic toner containing these pigments. Is excellent. In addition, excellent color reproducibility can be achieved without degrading the color balance even in toners of secondary colors (for example, green) obtained by mixing these Y color pigments with other primary colorants. Can be realized.
Also, a Y-color toner, which is an electrophotographic toner containing these pigments, and another primary color toner, that is, an M-color (magenta) magenta toner and a C-color (cyan) magenta toner. Even when a secondary color image is expressed by using the combination, excellent color reproducibility can be realized without destroying the balance of the target color.

As described above, the toner for electrophotography of the present embodiment has C.I. Pigment Yellow 111, C.I. Pigment Yellow 180 and C.I. In addition to being excellent in color development and sublimation resistance, the composition includes at least one of I pigment yellow 185, charging stability, fixability when forming a halftone image using the present electrophotographic toner, and Properties with excellent dot fixability can be obtained.
Although this principle is not clear, as described above, C.I. I. Pigment Yellow 111 is a pigment having excellent color developability. Pigment Yellow 180 and C.I. Since I Pigment Yellow 185 is a pigment having excellent thermal decomposition resistance and sublimation resistance, and there is little variation in the hue angle depending on the mixing ratio of these pigments, the electrophotographic toner contains these pigments. Therefore, it is considered that excellent color developability, heat decomposition resistance, and sublimation resistance can be obtained.

  In addition, C.I. C. I. Pigment Yellow 111 has an electrical polarity and causes an increase in charge. Pigment Yellow 180 and C.I. Since I Pigment Yellow has an electrical stabilization tendency, C.I. Pigment Yellow 111, C.I. Pigment Yellow 180 and C.I. By using in combination with at least one of the I pigment yellow 185, an increase in charging is reduced. This reduction in charge increase eliminates the variation in the amount of adhesion seen in isolated dots, etc. In addition to the above thermal decomposition resistance and sublimation resistance, charging stability and image density such as a halftone image It is considered that a fixing property at the time of forming an image with low image quality and an excellent dot fixing property can be realized.

Next, the configuration of the electrophotographic toner of this embodiment will be described in more detail. In the following, the electrophotographic toner of the present invention will be described by using a yellow (Y) yellow toner as a representative. However, in the image forming apparatus of the present invention to be described later, the present invention is used to form a full-color image. In addition to the yellow toner of yellow color as the toner corresponding to the electrophotographic toner of C.I. Pigment Yellow 111, C.I. Pigment yellow 180, and C.I. A case will be described in which magenta magenta toner, cyan cyan toner, and black black toner that do not include I pigment yellow 185 are used.
Therefore, in the following description, toners other than the yellow toner color (Y color) corresponding to the electrophotographic toner of the present invention will be described (basically, toners other than yellow toner are included in yellow toner). The above-mentioned C.I pigment yellow 111, C.I pigment yellow 180, and C.I pigment yellow 185 are the same except that they are changed to colorants described later).
Although not used in the present embodiment, when the secondary color toner using Y color is used, the above-described C.I. Pigment Yellow 111, C.I. Pigment Yellow 180 and C.I. In addition to I pigment yellow 185, a secondary color toner may be obtained by appropriately including a colorant other than the Y color described later.

(Binder resin)
The binder resin in the present invention is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include thermoplastic resins such as natural polymers and synthetic polymers. Preferred examples include resins, styrene-acrylic resins, polyacrylic resins, polyamide resins, polyester resins, polyvinyl resins, polyurethane resins, and polybutadiene resins. Among these, a polyester resin is preferable in terms of fixability and resin strength.

  The polyester resin preferably used in the present invention will be further described. The acid component used in the polyester resin includes, for example, terephthalic acid, isophthalic acid, orthophthalic acid, or anhydrides thereof, and preferably terephthalic acid / isophthalic acid. It is an acid. These acid components may be used alone or in combination of two or more. In addition, other acid components can be used in combination with the above acid components as long as the odor of flash fixing does not become a problem. Examples of other acid components include maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, malonic acid, and the like. -Butyl succinic acid, n-butenyl succinic acid, isobutyl succinic acid, isobutenyl succinic acid, n-octyl succinic acid, n-octenyl succinic acid, n-dodecyl succinic acid, n-dodecenyl succinic acid, isododecyl succinic acid, isododecenyl Examples also include alkyl or alkenyl succinic acids such as succinic acid, anhydrides of these acids, lower alkyl esters, and other divalent carboxylic acids. In addition, in order to crosslink the polyester resin, a trivalent or higher carboxylic acid component can also be mixed and used as another acid component. Examples of the trivalent or higher carboxylic acid component include 1,2,4-benzenetricarboxylic acid, 1,3,5-benzenetricarboxylic acid, other polycarboxylic acids, and anhydrides thereof.

  In addition, such a polyester resin is usually one in which 80 mol% or more of the alcohol component is composed of a bisphenol A alkylene oxide adduct, preferably 90 mol% or more, and more preferably 95 mol% or more. . If the amount of the bisphenol A alkylene oxide adduct is less than 80 mol%, the amount of the monomer used which causes the generation of odor relatively increases, which may be undesirable.

  Examples of the bisphenol A alkylene oxide adduct include polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3.3) -2,2-bis (4). -Hydroxyphenyl) propane, polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, Polyoxypropylene (2.0) -polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane Etc. These compounds may be used alone or in combination of two or more.

  In the polyester resin used as the binder resin in the present invention, other alcohol components may be used in combination with the above alcohol components, if necessary. Examples of other alcohol components include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-butenediol, 1 Diols such as 1,5-pentanediol and 1,6-hexanediol, bisphenol A, hydrogenated bisphenol A, and other dihydric alcohols.

  In addition, trihydric or higher alcohols are also suitable as other alcohol components. Examples of the alcohol component include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1, Examples thereof include 2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, and other trivalent or higher alcohols.

Further, in the reaction for synthesizing such a polyester resin, a commonly used esterification catalyst such as zinc oxide, stannous oxide, dibutyltin oxide, dibutyltin dilaurate, etc. is advantageously used in order to accelerate the reaction. Can be used.
The Tg (glass transition point) of the binder resin used for the toner described above is preferably in the range of 50 to 70 ° C.

  The weight average molecular weight and melting point of the binder resin are not particularly limited and may be appropriately selected depending on the intended purpose. For example, the weight average molecular weight is about 4000 to 100,000, and the glass transition point is about 70 to 130 ° C. Is preferred.

  There is no restriction | limiting in particular as content in the electrophotographic toner of the said binder resin, Although it can select suitably according to the objective, From points, such as charging property, 50 mass% or more is preferable, and 50-95 mass % Is more preferable.

(Coloring agent)
As the colorant, those shown below can be appropriately selected and used according to the color of the toner.
The yellow toner, which is the electrophotographic toner of the present invention, has been described above, and will not be described in detail. Pigment Yellow 111, C.I. Pigment Yellow 180 and C.I. And at least one of I Pigment Yellow 185. These contents and total contents are as described above.

  In the cyan cyan toner used together with the yellow toner during full color image formation, examples of the colorant include anilide compounds, benzidine, benzimidazolone, bisazo dyes, and the like. In addition, C.I. I. Pigment Blue 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 13, 16, 16, 17, 23, 60, the same 65, 73, 83, 180, C.I. I. Vat cyan 1, 3 and 20, etc., bitumen, cobalt blue, alkali blue lake, phthalocyanine blue, metal-free phthalocyanine blue, partially chlorinated phthalocyanine blue, first sky blue, indanthrene blue BC cyan pigment, C.I. I. Cyan dyes such as solvent cyan 79 and 162 can also be used.

As for the magenta toner used together with the yellow toner at the time of forming a full-color image, examples of the colorant include anthraquinone, quinacridone, bisazo dye, and monoazo dye.
In addition, C.I. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 41, 48, 49, 51, 52, 53, 54, 55, 57, 58, 60, 63, 64, 68, 81, 83, 87, 88, 89, 90, 112 114, 122, 123, 163, 184, 202, 206, 207, 209, etc., magenta pigments of Pigment Violet 19, C.I. I. Solvent Red 1, 3, 8, 23, 24, 25, 27, 30, 30, 49, 81, 82, 83, 84, 100, 109, 121, C . I. Disper thread 9, C.I. I. Basic Red 1, 2, 9, 9, 13, 14, 15, 17, 17, 18, 22, 23, 24, 27, 29, 32, 34, the same 35, 36, 37, 38, 39, 40, etc. Magenta dyes, etc., Bengala, Cadmium Red, Lead Tan, Mercury Sulfide, Cadmium, Permanent Red 4R, Resol Red, Pyrazolone Red, Watching Red, Calcium Salt, lake red D, brilliant carmine 6B, eosin lake, rotamin lake B, alizarin lake, brilliant carmine 3B, and the like can be used.

  Examples of the colorant used in the black black toner include various carbon blacks obtained by the thermal black method, acetylene black method, channel black method, lamp black method, and the like, and grafted carbon in which the carbon black surface is coated with a resin. Examples thereof include inorganic pigments such as black, ferrite, iron black, and magnetite, chromatic dyes / organic pigments, nigrosine dyes, and azo dyes.

Further, as described above, when the secondary color toner that can be expressed using the Y color is used, the above-described C.I. Pigment Yellow 111, C.I. Pigment Yellow 180 and C.I. Various colorants listed above may be appropriately selected and used together with at least one of I pigment yellow 185.
In the case of a green toner that is a secondary color, for example, a halogenated phthalocyanine may be used as a colorant.

The total content of the colorant contained in each color toner used at the time of forming a color image is not particularly limited, but is 0.1% with respect to 100% by mass of the toner prepared by mixing with a binder resin or the like. 10 mass% is preferable, and it is more preferable that it is 2-5 mass%.
When the total content of the colorant is less than 0.1% by mass, the coloration degree of an image made of toner fixed on a transfer member such as recording paper may deteriorate, and when the content exceeds 10% by mass. In addition, various characteristics such as charging stability of the toner may be deteriorated, and the raw material may be expensive.

(Other ingredients)
The electrophotographic toner can contain an infrared absorber as required. By containing this infrared absorber, the electrophotographic toner can be suitably used for image formation using photofixing.

As this infrared absorber, it refers to a material having at least one strong light absorption peak in the near infrared region in the wavelength range of 800 to 2000 nm, and it can be used as an organic material or an inorganic material.
As a specific example, a known infrared absorber can be used in combination, and there is no particular limitation, and it can be appropriately selected from known infrared absorbers. For example, an aminium compound, a diimonium compound, a cyanine compound , Polymethine compounds, nickel complex compounds, phthalocyanine compounds, indium oxide metal oxides, tin oxide metal oxides such as tin oxide, zinc oxide metal oxides, lanthanoid compounds, cadmium stannate, specific amide compounds, Etc. In addition, as an infrared absorber, cyanine compounds, merocyanine compounds, benzenethiol metal complexes, mercaptophenol metal complexes, aromatic diamine metal complexes, diimonium compounds, aminium compounds, nickel complex compounds, phthalocyanine compounds, anthraquinone compounds, Naphthalocyanine compounds and the like can also be used.

Among these, in the present invention, it is preferable to use a thermally stable toner because a toner is preferably produced by producing a master batch as described later.
Specific examples include cyanine-based infrared absorbers (trade names: CTP-1, IRF-106, IRF-107, manufactured by Fuji Photo Film Co., Ltd.), dian compounds (trade names: CY-2, CY, manufactured by Nippon Kayaku Co., Ltd.). -4, CY-9) and the like.

  Furthermore, nickel metal complex infrared absorbers (Mitsui Chemicals, trade names: SIR-130, SIR-132), bis (dithiobenzyl) nickel (Midori Chemicals, trade name: MIR-101), bis [1 , 2-bis (p-methoxyphenyl) -1,2-ethylenedithiolate] nickel (manufactured by Midori Chemical Co., Ltd., trade name: MIR-102), tetra-n-butylammonium bis (cis-1,2-diphenyl- 1,2-ethylenedithiolate) nickel (manufactured by Midori Chemical Co., Ltd., trade name: MIR-1011), tetra-n-butylammonium bis [1,2-bis (p-methoxyphenyl) -1,2-ethylenedithiolate ] Nickel (manufactured by Midori Chemical Co., Ltd., trade name: MIR-1021), bis (4-tert-1,2-butyl-1,2-dithiophenolate) ni Kel-tetra-n-butylammonium (manufactured by Sumitomo Seika Co., Ltd., trade name: BBDT-NI), soluble phthalocyanine (manufactured by Nippon Shokubai Co., Ltd .: TX-305A), naphthalocyanine (manufactured by Sanyo Pigment Co., Ltd., SnNc FT-1), Examples thereof include inorganic material systems (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: ytterbium UU-HP; manufactured by Sumitomo Metals Co., Ltd., indium tin oxide). These can be used in combination of two or more.

  Since these infrared absorbers greatly affect the color tone of the toner when added as described above, it is desirable to reduce the amount of the infrared absorber added as much as possible. For this reason, it is preferable to contain 0.1-20 mass% of these infrared absorbers in the total amount of components of the electrophotographic toner of the infrared absorber, and more preferably 0.5-5 mass%. When the content is less than 0.1% by mass, the light energy absorption performance in the near-infrared region of the electrophotographic toner may be deteriorated, resulting in poor fixing. Although the performance is good, problems such as charging failure and hue change may occur.

Further, the electrophotographic toner can contain a charge control agent as required.
This charge control agent is dispersed in the binder resin for the purpose of controlling the charge amount of the electrophotographic toner within a desired range.

  As the charge control agent, a positive charge control agent and a negative charge control agent are appropriately used depending on whether the binder resin is charged positively or negatively. Examples of the positive charge control agent include nigrosine dye (black), quaternary ammonium salt (colorless), triphenylmethane derivative (blue), and the like.

The color of the charge control agent is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably colorless or light-colored in that it has a small effect on the hue of the electrophotographic toner.
The content of the charge control agent in the electrophotographic toner is preferably 5% by mass or less, and more preferably 3% by mass or less.

  The electrophotographic toner may further contain other components appropriately selected according to the purpose. Examples of the other components preferably include a fixing aid, a metal soap, and a fluidizing agent. Can be mentioned.

  Examples of the fixing aid include waxes, metal soaps, and surfactants. The waxes are most preferably ester wax, polyethylene, polypropylene or a copolymer of polyethylene and polypropylene, but polyglycerin wax, microcrystalline wax, paraffin wax, carnauba wax, sazol wax, montanic acid ester wax, depolymerized wax. Acid carnauba wax, palmitic acid, stearic acid, montanic acid, blandic acid, eleostearic acid, valinalic acid and other unsaturated fatty acids, stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnauvir alcohol, ceryl alcohol, melyl alcohol Or a saturated alcohol such as a long-chain alkyl alcohol having a long-chain alkyl group; a polyhydric alcohol such as sorbitol; a linoleic acid amide Fatty acid amides such as oleic acid amide and lauric acid amide; saturated fatty acid bisamides such as methylene bis stearic acid amide, ethylene bis capric acid amide, ethylene bis lauric acid amide, hexamethylene bis stearic acid amide, ethylene bis oleic acid amide, Unsaturated fatty acid amides such as hexamethylene bisoleic acid amide, N, N′-dioleyl adipic acid amide, N, N′-dioleyl sebacic acid amide; m-xylene bisstearic acid amide, N, N′— Aromatic bisamides such as distearyl isophthalic acid amide; fatty acid metal salts such as calcium stearate, calcium laurate, zinc stearate, magnesium stearate (generally referred to as metal soap); Waxes grafted with vinyl monomers such as ethylene and acrylic acid; partially esterified products of fatty acids such as behenic acid monoglycerides and polyhydric alcohols; methyl esters having hydroxyl groups obtained by hydrogenation of vegetable oils and fats Compound etc. are mentioned.

  The wax that can be used in the color toner of the present invention is preferably ester wax, polyethylene, polypropylene, or a copolymer of polyethylene and polypropylene. The softening temperature is preferably 150 ° C. or less, and in particular, the binder resin is melted. Those exhibiting a softening temperature lower than the softening temperature are preferred.

  These waxes can be used alone or in combination of two or more. The addition amount of the wax in the present invention is preferably in the range of 0.1 to 10% by mass and more preferably in the range of 1 to 4% by mass in the total amount of the toner constituents finally produced. .

  Examples of the metal soap include zinc stearate. Examples of the surfactant include nonionic surfactants.

There is no restriction | limiting in particular as said fluidizing agent, Although it can select suitably according to the objective, For example, an inorganic fine particle, a resin particle, etc. are mentioned suitably. The inorganic fine particles are preferably used by external addition to the electrophotographic toner. The particle diameter of the inorganic fine particles is preferably 5 nm to 2 μm, more preferably ₅ nm to ₅₀₀ nm in terms of primary particle diameter (number average particle diameter (D ₅₀ )). The specific surface area of the inorganic fine particles by BET method is preferably 20 to 500 m ² / g. Examples of the inorganic fine particles include silica fine powder, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, Examples thereof include chromium oxide, cerium oxide, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride. Among these, silica fine powder is particularly preferable. These may be used individually by 1 type and may use 2 or more types together. Examples of the resin particles include polystyrene, polymethyl methacrylate (PMMA), and melamine resin. These may be used alone or in combination of two or more.

  The amount (external addition) of the fluidizing agent to the electrophotographic toner is 0.01 to 5 parts by mass with respect to 100 parts by mass in the electrophotographic toner (excluding the amount of fluidizing agent added). Is preferable, and 0.01-2.0 mass parts is more preferable.

  In producing the electrophotographic toner as described above, generally used kneading and pulverizing methods, wet granulation methods, and the like can be used. Here, as the wet granulation method, suspension polymerization method, emulsion polymerization method, emulsion polymerization aggregation method, soap-free emulsion polymerization method, non-aqueous dispersion polymerization method, in-situ polymerization method, interfacial polymerization method, emulsion dispersion granulation The law etc. can be used.

  In order to produce an electrophotographic toner by the kneading and pulverization method, a binder resin, an infrared absorber, an antioxidant, a wax, a charge control agent, a pigment or dye as a colorant, and other additives are added to Henschel. While mixing thoroughly with a mixer such as a mixer or ball mill, and melt-kneading using a heat kneader such as a heating roll, kneader or extruder to make the resins compatible with each other, an infrared absorber, an antioxidant, a pigment A toner can be obtained by dispersing or dissolving a dye, a magnetic substance, etc., cooling and solidifying, and then pulverizing and classifying. Moreover, in order to improve the dispersibility of a pigment and an infrared absorber, it is preferable to perform a masterbatch.

The master batch refers to a colorant (described above in C.I.) in the binder resin when the toner for electrophotography is produced by a melt-kneading and pulverizing method. In order to improve the dispersibility of CI Pigment Yellow 111, CI Pigment Yellow 180, CI Pigment Yellow 185, etc.), the colorant is added to the binder resin at a high concentration in advance and melted. A process of kneading, adding a binder resin to the kneaded material, and melt-kneading again.
By performing this master batch, among the above colorants, C.I. The dispersibility of the I pigment yellow 111 can be improved.

On the other hand, as a wet granulation method, for example, when prepared by an emulsion polymerization method, first, a monomer such as styrene, butyl acrylate, or 2-ethylhexyl acrylate is dissolved in water in which a water-soluble polymerization initiator such as potassium persulfate is dissolved. In addition, a surfactant such as sodium dodecyl sulfate is added as necessary, and polymerization is performed by heating while stirring to obtain resin particles (resin particle forming step).
Thereafter, in addition to the colorant and infrared absorber described above, if necessary, a powder such as a charge control agent and a wax composition is added to the suspension in which the resin particles are dispersed, and the pH, stirring strength, and temperature of the suspension are added. By adjusting the above, the resin particles, the colorant powder, the infrared absorbent powder and the like are heteroaggregated to obtain a heteroaggregate (aggregation step). Furthermore, the reaction system is heated to a temperature higher than the glass transition temperature of the resin particles to fuse the heteroaggregates to obtain colored particles (fusion process). Thereafter, the colored particles are washed and dried, and an external additive is added as necessary to obtain the color toner of the present invention.

The obtained toner particles preferably have a volume average particle diameter D50v of 3 to 15 μm, more preferably 5 to 15 μm, and particularly preferably 5 to 10 μm.
When the volume average particle diameter of the toner particles exceeds 15 μm, the toner particle diameter is large and an image with sufficient resolution cannot be obtained. On the other hand, when the thickness is less than 3 μm, the resolution of the obtained image is high, but the fluidity is low, so the image is not stable, which causes fogging and poor cleaning.

  As described above, the electrophotographic toner of the present invention has a toner particle size within a predetermined range and is less susceptible to an increase in charging due to the toner pigment. By using a predetermined amount of I pigment yellow 111, it is possible to control and stabilize the charge amount, and it is considered that the fixability of halftone images and dot fixability are excellent. Further, by adjusting the volume average particle diameter as described above, further fine line reproducibility and dot fixability can be obtained.

Note that the “halftone image” in the present embodiment specifically means an image having an image density in the range of 20% to 80%.
The “thin line” specifically means a linear image having a line width of 200 μm or less.

  The toner for electrophotography of the present invention is desirably a positively chargeable toner. Electrophotographic toner is often used in high-speed machines, and a positively charged photoconductor such as amorphous silicon, which will be described later, is used as a photoconductor for high-speed machines. Therefore, the toner for reversal development is positively charged. This is because it is desirable.

  The electrophotographic developer of the present embodiment (hereinafter sometimes referred to as a developer) is a one-component developer composed of the above electrophotographic toner, or two components composed of the above electrophotographic toner and a carrier. Any of the component developers may be used, but when used in a high-speed printer or the like corresponding to the recent improvement in information processing speed, the two-component developer is preferable from the viewpoint of improving the service life.

  As the carrier used as the two-component developer, it is preferable to use a carrier having a coating layer containing at least a silicone resin on the surface of the core material.

  As the material of the core material, for example, a manganese-strontium (Mn—Sr) -based material, a manganese-magnesium (Mn—Mg) -based material of 50 to 90 emu / g is preferable, and in terms of ensuring image density, iron Highly magnetized materials such as powder (100 emu / g or more) and magnetite (75 to 120 emu / g) are preferred, and weakly magnetized materials such as copper-zinc (Cu—Zn) (30 to 80 emu / g) are preferred. These may be used alone or in combination of two or more.

The particle diameter of the core material is preferably an average particle diameter (volume average particle diameter (D ₅₀ )) of 10 to 150 μm, and more preferably 40 to 100 μm. When the average particle diameter (volume average particle diameter (D ₅₀ )) is less than 10 μm, the distribution of carrier particles may increase the number of fine powders, lower the magnetization per particle, and cause carrier scattering. If the thickness exceeds 150 μm, the specific surface area may decrease and toner scattering may occur. In the case of a full color having a large solid portion, the reproduction of the solid portion may be deteriorated.

  The content of the silicone resin used as the coating layer of the carrier is preferably in the range of 0.1% by mass or more and 10% by mass or less, and 1.0% by mass or more and 5.0% by mass with respect to 100% by mass of the carrier. % Is preferably in the range of% or less. When the content of the silicone resin is less than 0.1% by mass, there is a problem that it is easily affected by the toner spent. When the content exceeds 10% by mass, the resistance of the carrier itself is easily increased and the toner is charged. There may be a problem that quantity control becomes difficult.

The silicone resin contained in the coating layer preferably contains at least 50 mol% to 90 mol%, more preferably 60 mol% to 85 mol%, and more preferably 70 mol% to 80 mol% as a constituent component. Is particularly preferred. By containing 50 mol% or more and 90 mol% or less of methylsiloxane in the silicone resin contained in the coating layer, the electrophotographic toner has positive chargeability as described above. The amount of charge can be reduced. The reason is that the dimethylsiloxane component is C.I. The increase in the charge amount with respect to I pigment yellow 111 can be further suppressed, and at the same time C.I. Pigment Yellow 180, C.I. It is presumed that any pigment of I pigment yellow 185 can be more positively charged, and as a result, a decrease in charging of the entire toner can be suppressed.
In addition to the above dimethylsiloxane, methylphenylsiloxane, diphenylsiloxane, methylethylsiloxane, ethylphenylsiloxane, phenylpropylsiloxane, and the like can be used as components constituting the silicone resin.

  The coating layer is prepared by, for example, dissolving the silicone resin in a solvent to prepare a coating solution, and then applying the coating solution to the surface of the core material by a known coating method such as a dipping method or a spray method, and then drying. Thereafter, it can be formed by baking or the like.

  There is no restriction | limiting in particular as said solvent, Although it can select suitably according to the objective, For example, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cellosol butyl acetate, etc. are mentioned. The baking may be an external heating method or an internal heating method, for example, a method using a stationary electric furnace, a fluid electric furnace, a rotary electric furnace, a burner furnace, a microwave, And the like.

  The ratio of the coating layer (coating amount) in the carrier is preferably 0.01 to 5.0% by mass with respect to the total amount of the carrier. If this ratio (coating amount) is less than 0.01% by mass, an appropriate coating layer may not be formed on the surface of the core material. If it exceeds 5.0% by mass, the coating layer becomes thick. In some cases, the carrier is granulated, and preferable carrier particles may not be obtained.

  In addition, when the developer in the present embodiment is a two-component developer, the content of the carrier in the two-component developer is not particularly limited and can be appropriately selected according to the purpose. 90-98 mass% is preferable and 93-97 mass% is more preferable.

  The image forming method using the electrophotographic toner of the present exemplary embodiment is not particularly limited, and may be referred to as, for example, an image carrier (hereinafter referred to as “photosensitive member”, “electrophotographic photosensitive member”, or the like as appropriate). .) Forming an electrostatic latent image on the surface, developing the formed electrostatic latent image with a developer containing the electrophotographic toner and forming a visible image, and forming the visible image A transfer step for transferring the image to the surface of the recording medium, and a fixing step for optically fixing the visible image transferred to the surface of the recording medium to the surface of the recording medium to form an image.

(Image forming apparatus and image forming method)
The image forming apparatus and the image forming method of the present embodiment transfer a toner image as a visible image by toner onto a recording medium using the developer containing the electrophotographic toner of the present embodiment described above, The toner image is not particularly limited as long as the image can be formed on the recording medium by optically fixing the toner image on the recording medium. Specifically, the image data on the image carrier is as follows. A latent image forming apparatus (latent image forming means, latent image forming step) for forming an electrostatic latent image corresponding to the image of the image, and developing the electrostatic latent image formed on the image holding member with the electrophotographic toner. A developing device (developing means, developing step) for forming a toner image as a visible image by developing with an agent, a transfer device (transfer method, transferring step) for transferring the toner image onto a recording medium as a member to be transferred, And a toner image is photofixed on the recording medium. A fixing device (fixing method, the fixing step) and, those having a.
In this case, the developer described above is used as the developer, and in the case of multicolor development, in addition to the yellow toner, a developer containing a chromatic toner such as cyan, magenta, and black is used. Used in combination.

  In addition to the above-described apparatus and process, the apparatus includes other apparatuses appropriately selected as necessary, for example, a cleaning apparatus (cleaning means, cleaning process) for removing deposits on the image carrier. May be.

  In addition, among the above devices (image holding member, latent image forming device, developing device, transfer device, and fixing device) provided in the image forming device, a developing device and at least one of the other devices form an image. You may provide so that attachment or detachment with respect to an apparatus main body is possible. A collective name of the detachable device group corresponds to the process cartridge of the present invention.

  The image can be formed as follows, for example. First, the surface of the electrophotographic photosensitive member as an image carrier is uniformly charged by a charging device, and then exposed by a latent image forming device for irradiating light modulated according to image data of an image to be formed. An electrostatic latent image corresponding to the image to be formed is formed on the electrophotographic photosensitive member. Next, a developer is supplied from the developing device to the electrostatic latent image on the electrophotographic photosensitive member to attach toner to the electrostatic latent image, thereby forming a visible toner image on the electrophotographic photosensitive member. . The formed toner image is transferred onto the surface of a recording medium (transfer target member) such as paper by a transfer device. Further, the toner image transferred to the surface of the recording medium is optically fixed by a fixing device, and an image is formed on the recording medium.

The electrophotographic photoreceptor preferably has a drum shape, and examples of the material include inorganic photoreceptors such as amorphous silicon and selenium, and organic photoreceptors such as polysilane and phthalocyanine.
Among these, an electrophotographic photosensitive member made of amorphous silicon is preferably used because it can cope with a high-speed process of 1000 mm / second or more and has a long life.

  The charging device for charging the surface of the electrophotographic photosensitive member can charge the surface of the electrophotographic photosensitive member by applying a voltage to the surface of the electrophotographic photosensitive member. Such a charging device is not particularly limited and may be appropriately selected depending on the purpose. For example, the charging device is known per se provided with a conductive or semiconductive roll, brush, film, rubber blade, or the like. Examples thereof include a contact charger, a non-contact charger using corona discharge such as corotron and scorotron.

  The exposure apparatus is not particularly limited as long as it can form a painter electric wire image corresponding to the image data on the surface of the electrophotographic photosensitive member charged by the charging apparatus, and can be appropriately selected according to the purpose. Examples include various exposure devices such as a copying optical system, a rod lens array system, a laser optical system, and a liquid crystal shutter optical system.

  The developing device stores the developer in a separate developing device for each developer including each color toner, and develops the electrostatic latent image on the corresponding electrophotographic photosensitive member. The developing device may be any device that supplies toner contained in the developer in contact or non-contact with the electrostatic latent image, and may be a dry development method or a wet development method. Alternatively, a single color developer or a multicolor developer may be used. As the developing device, for example, a device having a stirrer for charging the developer by frictional stirring and a rotatable magnet roller is preferably used.

As the fixing device, as described above, an optical fixing device that performs optical fixing is used. The light source used in this optical fixing device includes a normal halogen lamp, mercury lamp, flash lamp, infrared laser, and the like, and it is optimal because it can save energy by instantaneous fixing with a flash lamp.
The emission energy of the flash lamp is preferably 4.0 J / cm ² or more 12 J / cm ² or less in the range, and more preferably in the range of 4.0 J / cm ² or more 8.0J / cm ^2.

Here, the emission energy per unit area of flash light indicating the lamp intensity of xenon is expressed by the following equation (1).
S = ((1/2) × C × V ² ) / (u × L) × (n × f) (1)
In the above formula (1), n is the number of lamps that emit light at once (f), f is the lighting frequency (Hz), V is the input voltage (V), C is the capacitor capacity (F), u is the process transfer speed (cm / S), L represents the effective light emission width of the flash lamp (usually the maximum paper width, cm), and S represents the energy density (J / cm ² ).

The light fixing method is preferably a delay method in which a plurality of flash lamps emit light with a time difference. This delay system is a system in which a plurality of flash lamps are arranged, each lamp is delayed by about 0.01 to 100 ms, light is emitted, and the same portion is illuminated a plurality of times. As a result, the light energy can be divided and supplied to the toner image with a single light emission, so that the fixing efficiency can be improved, the occurrence of excessive fixing temperature is suppressed, and the void resistance and fixing property are improved. Can be compatible.
Here, when flash emission is performed on the toner a plurality of times, the emission energy of the flash lamp indicates the total amount of emission energy given to the unit area for each emission.

In the present embodiment, the number of flash lamps is preferably in the range of 1-20, and more preferably in the range of 2-10. Moreover, it is preferable that each time difference between several flash lamps is the range of 0.1-20 msec, and it is more preferable that it is the range of 1-3 msec.
Furthermore, once emission energy of light emitted in one flash lamp is preferably in the range of 0.1~1J / cm ^2, more preferably in the range of 0.4~0.8J / cm ^2.

Hereinafter, as an example of the image forming apparatus of the present invention, an image forming apparatus provided with a light fixing device (light fixing device) will be described with reference to the drawings.
FIG. 1 is a schematic diagram illustrating an example of the image forming apparatus. FIG. 1 shows a toner image formed by toner obtained by adding black to three colors of cyan, magenta, and yellow. The yellow toner corresponds to the electrophotographic toner of the present embodiment.

  In FIG. 1, 1a to 1d are charging devices, 2a to 2d are exposure devices, 3a to 3d are electrophotographic photosensitive members (image holding members), 4a to 4d are developing devices, and 10 is sent from the roll medium 15 in the direction of the arrow. Recording paper (recording medium), 20 is a cyan developing unit, 30 is a magenta developing unit, 40 is a yellow developing unit, 50 is a black developing unit, 70a to 70d are transfer rolls (transfer devices), 71 and 72 are rolls, 80 is The transfer voltage supply means 90 represents an optical fixing device (fixing device).

  An image forming apparatus 10 shown in FIG. 1 is arranged in contact with a recording sheet 11 and a developing unit for each color indicated by reference numerals 20, 30, 40, and 50 including a charging device, an exposure device, an electrophotographic photosensitive member, and a developing device. The transfer rolls 70a, 70b, 70c are arranged so as to contact the opposite sides of the rolls 71, 72 for conveying the recording paper 11 and the recording paper 11 so as to press the electrophotographic photosensitive member of each developing unit. 70d, transfer voltage supply means 80 for supplying voltage to these three transfer rolls, and the electrophotographic photosensitive member of the recording paper 11 passing through the nip portion between the electrophotographic photosensitive member and the transfer roll in the direction of the arrow in the figure. And an optical fixing device (fixing device) 90 that irradiates light to the contact side.

  The cyan developing unit 20 has a configuration in which a charging unit 1a, an exposing unit 2a, and a developing unit 4a are arranged around the electrophotographic photosensitive member 3a in a clockwise direction. Further, transfer is performed via the recording paper 11 so as to contact the surface of the electrophotographic photosensitive member 3a from the position where the developing unit 4a of the electrophotographic photosensitive member 3a is arranged to the time when the charging unit 1a is arranged clockwise. Rolls 70a are arranged to face each other. Such a configuration is the same for the developing units of other colors. In the image forming apparatus 10, a developer containing the yellow toner is stored in the developing unit 4 c of the yellow developing unit 40, and toner corresponding to each color is stored in the developing units of the other developing units. Is stored.

  Next, image formation using the image forming apparatus 10 will be described. First, in the black developing unit 50, the surface of the electrophotographic photosensitive member 3d is uniformly charged by the charging unit 1d while rotating the electrophotographic photosensitive member 3d in the clockwise direction. Next, the surface of the charged electrophotographic photoreceptor 3d is exposed by the exposure means 2d, so that a latent image corresponding to the yellow component image of the original image to be copied is formed on the surface of the electrophotographic photoreceptor 3d. The Further, the black toner stored in the developing means 4d is applied on the latent image to develop it to form a black toner image. This process is similarly performed in the yellow developing unit 40, the magenta developing unit 30, and the cyan developing unit 20, and a toner image of each color is formed on the surface of the electrophotographic photosensitive member of each developing unit.

  The toner images of the respective colors formed on the surface of the electrophotographic photosensitive member are sequentially transferred onto the recording paper 11 conveyed in the direction of the arrow by the action of the transfer potential by the transfer rolls 70a to 70d so as to correspond to the original image information. Are formed on the surface of the recording paper 11 to form a full-color laminated toner image in which cyan, magenta, and yellow are laminated in this order from the top layer.

  Next, the laminated toner image on the recording paper 11 is conveyed to the optical fixing device 90, where it is irradiated with light from the optical fixing device 80, melted, and optically fixed on the recording paper 11 to form a full color image. It is formed.

As described above, the electrophotographic toner used in the image forming apparatus 10 is an electrophotographic toner that has excellent fixability, color developability, and sublimation resistance, and excellent charging stability, and is formed by photofixing. The fine line reproducibility and dot fixability in the resulting image are also good.
For this reason, it is considered that good fixability can be obtained particularly when forming a halftone image or an image including fine lines.

  The toner for electrophotography of the present invention can be suitably used for various applications such as newspapers, service bureaus, barcode printing, label printing, tag printing, Carlson type or ion flow type printers and copying. In particular, even in the colored embodiment, since it is possible to provide a product that exhibits good flash fixability at low cost, it is possible to easily meet the demand for colorization of images in these applications.

Hereinafter, the present invention will be specifically described by way of examples.
(Examples 1-14 and Comparative Examples 1-5)
<Preparation of toner for electrophotography>
As binder resin, sulfonic acid modified polyester resin (acid value: 30 mg / KOH, softening temperature) having terephthalic acid, bisphenol A ethylene oxide 2-mole adduct, and bis (4-hydroxyphenyl) sulfonic acid as essential constituent monomers 104 ° C.) and this binder resin was treated with C.I. Pigment Yellow 111 (IRGALITE YELLOW F4G; manufactured by Ciba Specialty Chemicals), C.I. Pigment Yellow 180 (Novoperm P-HG; manufactured by Clariant Japan), C.I. I Pigment Yellow 185 (Paliotol Y-D1155; manufactured by BASF) was added in the composition (mass%) shown in Table 1 and Table 2, respectively, and calixarene compound (E-89, manufactured by Orient) 3 mass%. , Naphthalocyanine YKR-5010 (manufactured by Yamamoto Kasei Co., Ltd.) 0.65% by mass and ytterbium oxide UU-HP (manufactured by Shin-Etsu Chemical Co., Ltd.) 0.40% by mass are added to a Henschel mixer and premixed. After performing, it knead | mixed and kneaded at 140-145 degreeC and 250 rpm with the extruder (the Ikegai company make, PCM-30). Next, the mixture was coarsely pulverized with a hammer mill, finely pulverized with a jet mill, and then classified with an airflow classifier to obtain a toner base having a volume average particle diameter (D ₅₀ ) of 9.2 μm.

  Next, with respect to 100 parts by mass of the toner base, 0.35 parts by mass of hydrophobic silica (H-2000, manufactured by Clariant Co., Ltd.) as an external additive was externally added by a Henschel mixer. And the toner for electrophotography used for Comparative Examples 1-4 was obtained.

When the electrophotographic toner produced in Examples 1 to 14 was examined by a magnet blow-off method using a blow-off charge measuring device (manufactured by Toshiba Chemical), the positive electrode was charged and positive chargeability was confirmed. Had.
Since the produced toner was charged in the process of mixing and stirring with the carrier, a silicone resin-covered carrier described later was used.

  Further, as Comparative Example 5, the C.I. Pigment Yellow 111 (IRGALITE YELLOW F4G; manufactured by Ciba Specialty Chemicals), C.I. Pigment Yellow 180 (Novoperm P-HG; manufactured by Clariant Japan), C.I. C. I. Pigment Yellow 185 (Paliotol Y-D1155; manufactured by BASF) Pigment Yellow 180 (Novoperm P-HG; manufactured by Clariant Japan) and C.I. An electrophotographic toner according to Comparative Example 5 was obtained in the same manner as above except that I Pigment 74 was added in the composition shown in Table 2.

<Production of developer>
A two-component developer was prepared using the obtained toner. A ferrite carrier having a volume average particle diameter of 75 μm was used by coating the amount of dimethylsiloxane with respect to the silicone resin used as a carrier coating agent to be mixed with each of the toners as shown in Tables 1 and 2. . Then, 100 parts by mass of the carrier was mixed with 5 parts by mass of each toner, and mixed for 2 hours with a 10 L ball mill to prepare each developer.
The amount of dimethylsiloxane is the peak amount of dimethylsiloxane carbon relative to the total amount of the peak amount of dimethylsiloxane derived from the carbon and hydrogen peaks measured by NMR on the surface of the silicone resin and the peak amount derived from other carbon. I asked for it.
In addition, as a specific carrier production method, a carrier having 80 mol% of dimethylsiloxane is 64 parts by weight of SR2411 (manufactured by Toray Dow Corning Silicone, dimethyl silicone resin) and SH805 (manufactured by Toray Dow Corning Silicone, phenyl-containing silicone). Resin) 36 parts of toluene are added and mixed with 100 parts of toluene, put in 4000 parts by weight of 75 μm ferrite particles, mixed at 80 ° C. for 1 hour with a kneader, and then depressurized to distill off the solvent. After mixing for a time, baking was performed to obtain a carrier.
A carrier having 50 mol% of dimethylsiloxane was obtained by changing SR2411 to 35 parts by weight and SH805 to 65 parts by weight.
A carrier having 45 mol% of dimethylsiloxane was obtained by changing SR2411 to 1 part by weight and SH805 to 99 parts by weight.

  Using the developer prepared as described above, image evaluation was performed for fixability, color reproducibility, and sublimation resistance by the following methods, and evaluation was performed for change in chargeability.

  As an evaluation device, a flash fixing energy is obtained by using an ultra-high-speed flash printer (495J Continuous Feed Duplex Printer: equivalent to a printing speed of 460 ppm) equipped with a xenon flash lamp having a high emission intensity in a wavelength range of 700 to 1000 nm as an optical fixing device. The experiment was conducted by modifying the model so that it could be changed to 2.0 to 5.0 J / cm 2. Actually, the experiment was performed at 4.0 J / cm2. The linear speed (process speed) was 35.1 m / min. The electrophotographic photosensitive member is an electrophotographic photosensitive member having an amorphous silicon photosensitive layer, the developing device is a multi-stage developing device having two φ50 magnetic rollers, the transfer device is a corona transfer device, and a xenon flash lamp of an optical fixing device. Are provided on both sides.

As the recording medium, plain paper (NIP-1500LT, Kobayashi recording paper, continuous amount 64 g / cm ² ) was used, and an image of 1 inch square (2.54 cm × 2.54 cm) was formed by the image forming apparatus. Specifically, the image is adjusted (adjustment of development bias) so that the toner adhesion amount (toner applied amount on the recording medium) when a solid image (density 100%) is formed is 6 g / m ² . I went out.

(Fixability evaluation)
Plain paper (NIP-1500LT, Kobayashi recording paper) was used as a recording medium, and an image of 1 inch square (2.54 cm × 2.54 cm) was formed by the image forming apparatus. Specifically, as shown in Tables 1 and 2, a solid image with a density of 100% (toner loading 6 g / m ² on the recording medium) and a halftone image with an image density of 80% (toner loading on the recording medium). (Amount 7.0 g / m ² ), 20% image density halftone image (toner load 6.5 g / m ² on recording medium), line width 200 mm thin line image (toner load 8 g / m on recording medium) ² ) Each image was formed.

Next, the fixing rate of the obtained 1-inch square image was evaluated as follows. First, the status A density (OD1) corresponding to each color of the image is measured, and then an adhesive tape (Scotch Mending Tape, manufactured by Sumitomo 3M) is applied on the image, and then the adhesive tape is peeled off. The status A density (OD2) of the image was measured. In addition, (X-rite 938) was used for the measurement of optical density. Next, the fixing rate was calculated from the following equation (2) using the obtained optical density value.
Fixing rate (%) = OD2 / OD1 × 100 Formula (2)

The fixing property was evaluated according to the following criteria for the fixing rate calculated from Equation (2). The evaluation results are shown in Tables 1 and 2.
A: The fixing rate is 95% or more.
A: The fixing rate is 85% or more and less than 95%.
Δ: The fixing rate is 80% or more and less than 85%.
X: The fixing rate is less than 80% (a level that is difficult to use).

(Dot fixability evaluation)
For the halftone image (toner loading of 6.5 g / m ² on the recording medium) formed in the above fixing property evaluation, the missing state of each dot forming this halftone image was observed, and sensory evaluation Went. Specifically, focusing on the particle size of the dots, each was evaluated according to the following criteria. The evaluation results are shown in Tables 1 and 2.

A: No missing dot. O: A dot is observed in an area of less than 20% of the entire image area.
(Triangle | delta): The chip | tip in the area | region of less than 60% and 20% or less of the whole image area is seen.
X: Chips are observed in dots in an area of 60% or more of the entire image area.

(Evaluation of color reproducibility (color development))
Using each of the toners, a solid image is formed (solid image with a density of 100% (toner loading 6 g / m ² ) on the recording medium) and fixed, and color reproducibility measurement values (L ^* , a ^{* And} b ^* ) were evaluated. In addition, each numerical value of L ^* , a ^* , and b ^* is measured with a spectrometer (938 Spectrodentitometer, X-Rite Co., Ltd.) saturation C = ((a *) ² + (b *) ² ) ^1/2 did. From this measurement result, the color reproducibility was evaluated according to the following criteria. The evaluation results are shown in Tables 1 and 2.

When saturation C is 70 or more ...
When saturation C is 65 or more and less than 70
When saturation C is 60 or more and less than 65 ... △
When saturation C is less than 60

(Evaluation of bleeding / printing stain density (sublimation resistance))
Using each toner, a solid image was formed (solid image with a density of 100% (toner loading 6 g / m ² on the recording medium)) and fixed, and the smear density in the vicinity of the printing portion was determined. Evaluation was performed according to the following evaluation criteria based on the color difference (ΔE) based on standard paper (L * = 89.20, a * = − 0.28, b * = 0.73). The evaluation results are shown in Tables 1 and 2.

The color difference ΔE was determined by measuring L ^* , a ^* , and b ^* with a spectrometer (938 Spectrodentitometer, X-Rite Co.) for the smeared and stained area near the printed portion, and calculating the color difference ΔE by the following formula (3).
ΔE = {(L ₀ ^* −L ₁ ^* ) ² + (a ₀ ^* −a ₁ ^* ) ² + (b ₀ ^* −b ₁ ^* ) ² } ^1/2 Formula (3)
Here, L ₀ ^* , a ₀ ^* , and b ₀ ^* are reference values of standard paper, and L ₀ ^* = 89.20, a ₀ ^* = − 0.28, and b ₀ ^* = 0.73, respectively. did. L ₁ ^* , a ₁ ^* , and b ₁ ^* indicate measured values of the toner image.

When the color difference (ΔE) is 3 or less.
When color difference (ΔE) is more than 3 and less than 5
When the color difference (ΔE) is more than 5 and 10 or less ... △
When color difference (ΔE) is more than 10

(Evaluation of charging stability)
Using the above, continuous operation was performed in white solid printing (image density 0%), the developer was sampled 60 minutes later, and the charge amount was measured using a blow-off charge amount measuring machine (manufactured by Toshiba Chemical). The measurement results were evaluated according to the following evaluation criteria. The evaluation results are shown in Tables 1 and 2.

The charge amount before and after continuous operation was measured and evaluated according to the following evaluation criteria.
Charge fluctuation is 3μC / g or less ...
Charge amount fluctuation range is more than 3μC / g to 5μC / g or less.
The fluctuation amount of the charge amount is more than 5 μC / g to 10 μC / g or less.
The fluctuation amount of the charge amount is over 10μC / g ・ ・ ・ ×

From the results shown in Tables 1 and 2, the following is clear.
As seen in Examples 1-7, C.I. Pigment Yellow 111, C.I. In the toner containing I Pigment Yellow 180, good results were obtained in all the items of fixability, color reproducibility, sublimation resistance, dot fixability, and charging stability. From the viewpoint of characteristics, regarding the fixing property, C.I. The higher the content of I pigment yellow 111, the better, and the addition of 1% by mass or more is more preferable. However, as the content is increased, the charging property is deteriorated. It can be seen that it is preferable to increase the content of I Pigment Yellow 180 as well.

  Then, as seen in Example 3, Example 9, and Example 10, C.I. Pigment Yellow 111 and C.I. I Pigment Yellow 185, and C.I. Pigment Yellow 111, C.I. Pigment yellow 180, and C.I. Even when I Pigment Yellow 185 was used in combination, good results were obtained in all the items of fixability, color reproducibility, sublimation resistance, toner reproducibility, and charging stability.

  Further, as can be seen from Examples 1 to 8, in terms of fixability, good fixability could be obtained in any of solid images, images with an image density of 80%, images with a density of 20%, and fine line images. .

  On the other hand, as seen in Comparative Example 1, Comparative Example 2, and Comparative Example 3, C.I. Pigment Yellow 111, C.I. Pigment yellow 180, and C.I. When each of I Pigment Yellow 185 was used alone, good results could not be obtained in any of the items of fixability, color reproducibility, sublimation resistance, and charging stability, and all evaluation items were Satisfactory results were not obtained. Also, good results were not obtained for dot fixability.

  As seen in Comparative Example 5, C.I. Pigment Yellow 111, and C.I. When I Pigment Yellow 74 was used in combination, solid image fixability was good, but the image density was 80%, 20% halftone image and fine line image fixability, and charging stability. Good results were not obtained.

  Further, in Comparative Example 1 and Comparative Example 4, solid image fixability is good, but good fixability can be obtained in any of an image density of 80%, a 20% image, and a fine line image. could not. For this reason, in Examples 1 to 14, it can be said that good fixability could be obtained even in a halftone image and a fine line image having an image density of 20% or less.

  Furthermore, the same items as described above were evaluated using the developer produced in Example 3 as a developer containing yellow toner of ApeosPort C6550I manufactured by Fuji Xerox, which is a heat roll fixing type color printer instead of flash fixing. As a result, it was confirmed that there were no problems with respect to all the items of fixability, color reproducibility, sublimation resistance, dot fixability, and charging stability.

1 is a schematic configuration diagram illustrating an example of an image forming apparatus of the present invention. It is a graph which shows an example of the emission spectrum of a xenon flash lamp.

Explanation of symbols

1a, 1b, 1c, 1d Charging means 2a, 2b, 2c, 2d Exposure means 3a, 3b, 3c, 3d Electrophotographic photoreceptors 4a, 4b, 4c, 4d Developing means 10 Recording paper (recording medium)
20 Cyan developing unit 30 Magenta developing unit 40 Yellow developing unit 50 Black developing units 70a, 70b, 70c, 70d Transfer means 71, 72 Roller 80 Transfer voltage supply means 90 Light fixing means (fixing means)

Claims (8)

  At least a binder resin; Pigment Yellow 111, C.I. Pigment Yellow 180 and C.I. An electrophotographic toner comprising: at least one of I pigment yellow 185.   C. I pigment yellow 111 is contained in an amount of 1 to 10% by weight, and C.I. I Pigment Yellow 180 in an amount of 1% by mass to 5% by mass or C.I. The electrophotographic toner according to claim 1, wherein I pigment yellow 185 is contained in an amount of 1% by mass to 2% by mass.   C. Pigment Yellow 111, C.I. Pigment Yellow 180 and C.I. 3. The electrophotographic toner according to claim 1, wherein the total content of at least one of I pigment yellow 185 is 5% by mass or more and 15% by mass or less.   The toner for electrophotography according to any one of claims 1 to 3, wherein the toner is a positively chargeable toner.   An electrophotographic developer comprising: the electrophotographic toner according to any one of claims 1 to 4; and a carrier having a coating layer containing at least a silicone resin on a core material surface.   6. The electrophotographic developer according to claim 5, wherein the silicone resin contained in the coating layer contains 50 mol% or more and 90 mol% or less of dimethylsiloxane as a constituent component.   A process comprising at least developing means for developing the electrostatic latent image formed on the surface of the image carrier with the electrophotographic developer according to claim 5 to form a visible image. cartridge. An image carrier,
Charging means for charging the surface of the image carrier;
Latent image forming means for forming an electrostatic latent image on the surface of the image carrier charged by the charging means;
Developing means for developing the electrostatic latent image with the electrophotographic developer according to claim 5 to form a visible image;
Transfer means for transferring the visible image to a transfer member;
An irradiating means for irradiating light to the visible image transferred to the member to be transferred includes light having a light emission energy of ⁴ J / cm ² or more from the irradiating means to fix the visible image to the member to be transferred. Fixing means,
An image forming apparatus comprising:

Images