JP4492263B2 - Manufacturing method of color toner for light fixing - Google Patents

Description

The present invention relates to an optical fixing color toner manufacturing how for use in electrophotographic image formation.

  In the electrophotographic system widely used in copying machines, printers, printing machines, etc., image formation is generally performed as follows. First, after a charging step for giving a positive or negative uniform electrostatic charge to the photoconductive insulator surface of the photoconductive drum, the photoconductive insulator surface is irradiated with, for example, laser light, and the electrostatic charge on the insulator surface is reduced. An electrostatic latent image corresponding to image information is formed by partially erasing. Next, for example, a fine powder of a developer called toner is attached to the latent image portion on which the electrostatic charge remains on the photoconductive insulator, and the latent image is visualized as a toner image. In order to make the toner image thus obtained into a printed matter, generally, the toner image is electrostatically transferred to a recording medium such as recording paper, and then the toner image is fixed to the recording medium.

  For fixing the toner image after the transfer, a method of solidifying and fixing after melting the toner by pressure, heating, or a method using a combination thereof, or a method of solidifying and fixing after melting the toner by irradiating light energy However, a light fixing method (also called a flash fixing method) using light that does not cause harmful effects due to pressure or heating has attracted attention.

  That is, in the photofixing method, since it is not necessary to pressurize the toner when fixing the toner, it is not necessary to make contact (pressurization) with a fixing roller or the like, and there is little deterioration in image resolution (reproducibility) in the fixing process. There are advantages. In addition, since there is no need to heat with a heat source, printing does not occur until the heat source (fixing roller, etc.) is preheated to the desired temperature after the power is turned on. Yes. In addition, since a high-temperature heat source is not required, there is an advantage that the temperature rise in the apparatus can be appropriately avoided, and even when a recording paper jam occurs in the fixing device due to a system down, The recording paper is not ignited by heat.

  However, when it is used for fixing a color toner, the light fixing method has a lower fixability than the fixing of a black toner (black toner) due to the low light absorption efficiency of the color toner. Therefore, many proposals have been made to improve the fixing property by adding an infrared absorber to the color toner (for example, see Patent Documents 1 to 10). In these proposals, a material that absorbs light in the infrared region is added to the toner as an infrared absorber, thereby solving the problem of lowering the toner meltability and trying to achieve both colorization and photofixability.

  On the other hand, a toner containing an infrared absorber can be used for forming an invisible image as an invisible toner when no colorant is added. In this case, the fixing method is not particularly limited, and a heat roll method, an oven method, a light method, and the like. Known fixing methods such as a fixing method and an infrared irradiation fixing method can be used.

  The invisible image is an infrared absorption pattern formed on the surface of a recording medium, and an information pattern having some specific information such as personal information or a non-information pattern such as a detection mark can be applied to the recording medium. . An example of the information pattern is a code pattern. An example of the code pattern is a barcode, and the barcode includes a two-dimensional code in addition to the one-dimensional barcode. The detection mark is a mark provided for setting a paper feed timing of a transparent sheet that is not optically detected when an image is formed by a copying machine using an optical detection method.

  In the detection device used to identify the infrared absorption pattern of these invisible images, a conventionally known infrared light source such as an infrared LED (light emitting diode) or an infrared laser can be used as it is. It is. The infrared absorption pattern can be detected using, for example, a CCD sensor.

  By the way, in the production of toner, generally, a toner composition such as a binder resin, a colorant, and a charge control agent is premixed with a powder mixer such as a Henschel mixer and then continuously mixed with a kneading apparatus such as a twin screw extruder. By feeding and melt-kneading, an additive such as a colorant is dispersed in the binder resin, and the kneaded product is pulverized and classified continuously. The degree of dispersion of the colorant and other additives and the uniformity of the concentration in the binder resin are important factors that affect the physical properties of the toner.

  In particular, in color toners and invisible toners for photofixation formed by blending the infrared absorber, dispersion of the infrared absorber in the toner and variations in density are factors that are directly related to toner fixability and image reading characteristics. Therefore, the required degree of dispersion and uniformity of density are very high.

  That is, the poor dispersion, excessive dispersion, and non-uniform density of the infrared absorber cause not only fixing failure in light fixing, for example, but also the flash light is absorbed locally when the infrared absorber is localized. Excessive heat generation is likely to occur, and voids (white spots) may occur in the toner image portion. Further, in addition to the problem of infrared absorptivity, there is a problem with the charging property of the toner due to the influence of the structure and functional group of the compound of the infrared absorber.

  However, since the amount of the infrared absorber added is smaller than that of the binder resin, the colorant, etc., the toner that is continuously melt-kneaded and extruded during the toner production even if the preliminary mixing is sufficiently performed when the toner is produced. It is very difficult to make the infrared absorber concentration in each minute portion in the composition constant. Further, since toner productivity is also a very important point, the melt kneading time in a twin-screw extruder or the like is limited during the melt kneading, and it cannot be said that kneading is sufficient to uniformly disperse the infrared absorber. There are many cases.

As described above, for color toners and invisible toners for photofixation, it is desired to develop a technique for uniformly and finely dispersing an infrared absorber in a toner composition such as a binder resin, a colorant, and a charge control agent in the production thereof. It is rare.
JP-A-60-63545 JP-A-60-57858 JP-A-60-131544 JP 61-132959 A JP-A-7-191492 Japanese Patent Laid-Open No. 10-39535 JP-A-11-38666 JP-A-11-65167 JP-A-11-125930 JP 2000-35689 A

The object of the present invention is to solve the above-mentioned problems in the prior art.
That is, the present invention aims at providing an infrared absorber binder resin, a colorant, producing how the color toner for optical fixing which can be optimally dispersed in the toner composition such as a charge control agent . The present invention is aimed at providing a high infrared absorptivity good has light fixability, and the economically cheaper optical fixing color toner manufacturing how.

The above-mentioned subject is achieved by the following present invention. That is, the present invention
<1> A method for producing a color toner for photofixing comprising at least a polyolefin resin, a colorant, and a diimonium compound having a turbidity of less than 25% when added to the polyolefin resin,
Step of preparing a master batch which contains previously polyolefin resin and / or the diimmonium compound to component containing a wax at a concentration ranging from 50 to 80 wt%, the master batch was mixed with the other toner components And a kneading and pulverizing step in which the toner composition is melt-kneaded, cooled, and then pulverized to form toner particles. A toner manufacturing method.

<2> In the step of producing the master batch, relative to component comprising a polyolefin resin and / or wax contain a colorant together with the diimmonium compound, in the step of preparing the toner composition is mixed with other toner ingredients <1> The method for producing a color toner for photofixing according to <1>.

<3> A method for producing a color toner for photofixing comprising at least a polyolefin resin, a colorant, and a naphthalocyanine compound having a turbidity of 25% or more when added to the polyolefin resin,
Step of preparing a masterbatch to component pre comprising a polyolefin resin and / or wax is contained the naphthalocyanine compound to a concentration in the range of 40 to 80 wt%, mixing the master batch with the other toner components And a toner composition containing a naphthalocyanine compound having a desired concentration, and a kneading and pulverizing step in which the toner composition is melt-kneaded, cooled and pulverized to form toner particles. This is a manufacturing method for color toner.

<4> In the step of producing the master batch, relative to component comprising a polyolefin resin and / or wax contain a colorant with the naphthalocyanine compound, in the step of preparing the toner composition, the other toner ingredients mixed <3> The method for producing a color toner for photofixing according to <3>.

According to the present invention, the infrared absorbing agent binder resin, a colorant, can be optimally dispersed in the toner composition such as a charge control agent, also has good have light fixability high infrared absorbing ability, and it is possible to provide an economically cheaper optical fixing production how the color toner. Furthermore, by making the infrared absorber into a master batch simultaneously with the colorant, the color reproducibility can be improved and the cost can be reduced.

Hereinafter, the present invention will be described in detail.
The first method for producing a color toner for photofixation of the present invention is a method for producing a color toner for photofixation containing at least a polyolefin resin, a colorant, and a diimonium compound having a turbidity of less than 25% when added to the polyolefin resin. a manufacturing method, the step of producing a master batch which contains the diimmonium compound to components previously comprising a polyolefin resin and / or wax at a concentration ranging from 50 to 80 wt%, other the masterbatch And a step of preparing a toner composition containing a diimonium compound at a desired concentration by mixing with the toner component, and a kneading and pulverizing step of melting and kneading and cooling the toner composition to form toner particles. And

The second method for producing a color toner for photofixation according to the present invention comprises at least a polyolefin resin, a colorant, and a naphthalocyanine compound having a turbidity of 25% or more when added to the polyolefin resin. a method of manufacturing a color toner, a step of preparing a master batch which contains previously polyolefin resin and / or the naphthalocyanine compound to component containing a wax at a concentration ranging from 40 to 80 wt%, the A step of preparing a toner composition containing a naphthalocyanine compound of a desired concentration by mixing the master batch with other toner components, and a kneading and pulverizing step of melting and kneading the toner composition, cooling and pulverizing the toner composition into toner particles It is characterized by including

In the present specification , the invisible toner is a toner for deciphering using invisible light such as infrared rays. When the toner image is fixed on a sheet or the like as a toner image, the toner is slightly colored and may be visually recognized. And toner that can be read by invisible light. That is, it refers to toner for forming an invisible image such as an infrared absorption pattern such as a barcode. If the colorant is 1% or less of a level where the presence of the colorant is clearly not confirmed, it can be called an invisible toner if necessary. Therefore, the configuration of the invisible toner except that basically does not contain a colorant, Ru der those similar to the basic color toner for optical fixing arrangement. Hereinafter, the light fixing color toner and the invisible toner (hereinafter, these may be simply referred to as “toner”) in the present invention will be described together.
Note that the non-visible toner, an invisible toner to be light fixing are also included.

  As described above, when a toner containing an infrared absorber is produced by the kneading and pulverizing method, it is very difficult to make the concentration of the infrared absorber for each minute portion in the toner composition constant, and the usual melt-kneading is performed. If it is continuously manufactured under the conditions, the infrared absorber is poorly dispersed, excessively dispersed, and non-uniform in density. For example, it causes fixing problems in photofixing. In addition, if it is attempted to improve the dispersibility of the infrared absorbent during melt kneading, it takes time for kneading and causes an increase in manufacturing cost.

As a result of intensive studies by the present inventors to achieve the above-mentioned objects, production of a toner containing at least a polyolefin resin, a colorant, and a dimonium compound having a turbidity of less than 25% when added to the polyolefin resin. a method is the diimmonium compound to prepare a master batch which contains a high concentration of a specific range, the masterbatch except an infrared absorber in the infrared-absorbing agent to component comprising pre polyolefin resin and / or wax When a toner composition containing an infrared absorber having a desired concentration is mixed (diluted) with other toner components, and the toner is produced by a kneading and pulverizing method, the infrared absorber is uniformly distributed in the toner particles. It was found that a dispersed toner can be obtained.

Specifically, in the method for producing a color toner for photofixation of the present invention, the turbidity when added to a soluble infrared absorber described later , that is, a polyolefin resin that is a main component of a masterbatch is less than 25% . In the case of using a certain dimonium compound, the master batch is prepared so that the concentration of the infrared absorber in the whole is in the range of 50 to 80% by mass (first method for producing a color toner for light fixing), and When using a naphthalocyanine compound which is an insoluble infrared absorber described later, the master batch is prepared so that the concentration of the infrared absorber in the whole is in the range of 40 to 80% by mass (second Manufacturing method of color toner for light fixing).

  The master batch in which the infrared absorber is present at each concentration is mixed with other toner components other than the infrared absorber to obtain a toner composition containing an infrared absorber having a desired concentration, and the obtained toner composition The product is melt-kneaded, cooled, and pulverized to obtain a color toner for photofixing in which an infrared absorber having a desired concentration is uniformly dispersed in toner particles.

  Here, in the present invention, the term “uniformly dispersed in the toner particles” means that the infrared absorbent domains having a size of 3 μm or less, preferably 0.5 μm or less, are dispersed in the toner particles without being unevenly distributed. That means. This dispersed state can be confirmed by observing the toner particles or the flakes of the toner composition under a microscope.

In the first method for producing a color toner for light fixing according to the present invention, the concentration of the diimonium compound having a turbidity of less than 25% when added to the polyolefin resin in the entire master batch is in the range of 50 to 80% by mass. It is necessary to be. Further, in the second method for producing a color toner for light fixing according to the present invention, the turbidity when added to an insoluble infrared absorbent in the whole masterbatch, that is, a polyolefin resin which is a main component of the masterbatch. The concentration of the naphthalocyanine compound in which is 25% or more is required to be in the range of 40 to 80% by mass, and preferably in the range of 50 to 70% by mass.

The concentration of the infrared absorber in the masterbatch is 50 % by mass in the first method for producing a color toner for light fixing of the present invention, and 40% by mass in the second method for producing a color toner for light fixing of the present invention. If not, the color toner for photofixation cannot sufficiently absorb infrared rays when photofixed, resulting in poor fixing. Further, when the concentration of the infrared absorbent exceeds 80% by mass in both the first and second photofixing color toner production methods of the present invention, the photofixability is lowered and the coloring effect by the infrared absorbent is remarkable. Therefore, the color reproducibility is lowered, and it becomes difficult to cancel the color gamut shift caused by the infrared absorber.

Furthermore, in the method for producing a color toner for light fixing according to the present invention, in consideration of economic cost merit, a master containing a polyolefin resin and / or a wax containing a colorant together with an infrared absorber in a high concentration. Using a batch, other toner components are blended into the master batch to obtain a toner composition containing an infrared absorber at a desired concentration, and the obtained toner composition is melt-kneaded, cooled and pulverized to absorb infrared rays. It is advantageous in that the cost can be reduced and the color reproducibility can be improved compared to the case of separately mastering the colorant and the colorant.

In addition, in the method for producing an invisible toner, regardless of whether the turbidity when the infrared absorber is added to the polyolefin resin is less than 25% or 25% or more , the concentration of the infrared absorber in the whole is not limited. A master batch was prepared so as to be in the range of 2 to 80% by mass, and the master batch was blended with other toner components other than the infrared absorber to obtain a toner composition containing an infrared absorber having a desired concentration. By melting and kneading the toner composition, cooling and pulverizing, an invisible toner in which an infrared absorbent having a desired concentration is uniformly dispersed in the toner particles can be obtained.

As described above, since the infrared absorbent is uniformly dispersed in the toner particles, coloring of the invisible toner can be suppressed, the concentration of the infrared absorbent can be reduced, and a reliable signal grasp of the invisible image can be performed.
The meaning of the uniform dispersion of the infrared absorbent in the toner particles is the same as that in the method for producing the color toner for light fixing.

In the method for producing an invisible toner, the concentration of the infrared absorber having a turbidity of less than 25% when added to the polyolefin resin in the entire master batch is preferably in the range of 30 to 80% by mass.

  When the concentration of the infrared absorber in the master batch is less than 2% by mass, the infrared ray cannot be sufficiently absorbed in the fixed invisible image, so that the signal information cannot be read reliably. On the other hand, when the concentration of the infrared absorbent exceeds 80% by mass, the coloring effect by the infrared absorbent becomes remarkable, and an invisible image that cannot be recognized visually cannot be obtained.

Hereinafter, the method for producing the toner of the present invention will be described more specifically.
A method for producing a toner of the present invention may use each kind of coloring agent. The main component of the binder resin, but port re-olefin is preferably a copolymer of styrene and acrylic acid or methacrylic acid, polyvinyl chloride, phenol resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone resins, polyester resin, polyurethane, polyamide resins, furan resins, epoxy resins, xylene resins, polyvinyl butyral, terpene resin, coumarone-indene resin, that petroleum resins, polyether polyol resins or the like such as for 併. From the viewpoint of the durability and light-transmitting property, it is preferred to use a Bruno Le Bol Nene polyolefin resin.
The Tg (glass transition point) of the binder resin used for the toner is preferably in the range of 50 to 70 ° C.

In the method for producing a color toner for light fixing according to the present invention, the following colorants can be appropriately selected and used corresponding to the color of the toner.
In the cyan toner, as the colorant, for example, C.I. I. Pigment Blue 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 13, 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 16, 17, 17, 23, 60, 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 products of phthalocyanine blue, fast sky blue, indanthrene blue BC cyan pigment, C.I. I. Cyan dyes such as solvent cyan 79 and 162 can be used. Among these, C.I. I. Pigment Blue 15: 3 is effective.

  In the magenta toner, as the colorant, for example, C.I. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 11, 12, 13, 15, 15, 16, 17, 18, 19, 21, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 41, 48, 49, 50, 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, and 209, pigment violet 19 magenta pigments, 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.

  In the case of yellow toner, examples of the colorant include C.I. I. Yellow pigments such as CI Pigment Yellow 2, 3, 3, 15, 16, 17, 97, 180, 185, and 139 can be used.

  In the black toner, as the colorant, for example, carbon black, activated carbon, titanium black, magnetic powder, Mn-containing nonmagnetic powder, or the like can be used. The color toner for light fixing of the present invention includes black toner mixed with yellow, magenta, cyan, red, green and blue pigments.

  The amount of each colorant added in the method for producing a color toner for photofixing of the present invention is in the range of 1 to 20 parts by mass in 100 parts by mass of final toner particles prepared by mixing with a binder resin or the like. It is preferable.

On the other hand, the non-visible toner, to avoid using a colorant as described above. However, depending on the type of infrared absorber described later, various pigments and the like can be added to cancel the coloring caused by the infrared absorber.

  In the present invention, the infrared absorber added to the toner 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. It can be used.

  Specific examples include known infrared absorbers such as 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 be used.

  In the method for producing a color toner for light fixing according to the present invention, a preferable concentration of the infrared absorbent to be contained in the masterbatch is selected depending on the solubility of the infrared absorbent in the binder resin. In the present invention, a case where the turbidity when added to a binder resin using an infrared absorber is less than 25% is referred to as a “soluble infrared absorber”, and a case where the turbidity is 25% or more is referred to as “non-soluble” Infrared absorber ".

In the present invention, the turbidity value was measured as follows.
First, 0.1 part by mass of an infrared absorber is added to 100 parts by mass of a binder resin (including a compatibilizer when added), and 120 ° C. using a lab plast mill (60 cc) manufactured by Toyo Seiki. Then, the kneaded product was sandwiched between Teflon (registered trademark) sheets and pressed with a hot press, and a resin containing an infrared absorbent was molded into a 0.3 mm thick film to obtain a measurement sample. Subsequently, the turbidity was determined by using this film with a turbidimeter (color computer SM-3 (measurement unit: HGM-2K), manufactured by Suga Test Instruments Co., Ltd.) according to JIS K7105 (haze measurement method).

  From the examination results of the present inventors, for example, when a polyester resin is used, as a typical infrared absorber having a turbidity of less than 25%, a cyanine compound, a merocyanine compound, a benzenethiol metal complex, a mercaptophenol metal complex , Aromatic diamine-based metal complexes, diimonium compounds, aminium compounds, nickel complex compounds, and soluble (modified) phthalocyanines. Typical infrared absorbers having a turbidity of 25% or more are phthalocyanine compounds, anthraquinone compounds, naphthalocyanine compounds, and ytterbium compounds.

  More specifically, examples of infrared absorbers that are soluble in polyester resins include nickel metal complex infrared absorbers (manufactured by Mitsui Chemicals: SIR-130, SIR-132), bis (dithiobenzyl) nickel (green) Chemical company: MIR-101), bis [1,2-bis (p-methoxyphenyl) -1,2-ethylenedithiolate] nickel (manufactured by Midori Chemical Co .: MIR-102), tetra-n-butylammonium bis (Cis-1,2-diphenyl-1,2-ethylenedithiolate) nickel (manufactured by Midori Chemical Co., Ltd .: MIR-1011), tetra-n-butylammonium bis [1,2-bis (p-methoxyphenyl) -1 , 2-Ethylenedithiolate] nickel (manufactured by Midori Chemical Co., Ltd .: MIR-1021), bis (4-tert-1,2-butyl-1,2- Thiophenolate) Nickel-tetra-n-butylammonium (manufactured by Sumitomo Seika Co., Ltd .: BBDT-NI), cyanine infrared absorber (Fuji Photo Film Co., Ltd .: IRF-106, IRF-107), cyanine infrared absorber (Yamamoto Kasei Co., Ltd., YKR2900), aminium, diimonium-based infrared absorber (Nagase Chemtech Co., Ltd .: NIR-AM1, IM1), imonium compound (Nippon Carlit Co., Ltd .: CIR-1080, CIR-1081), aminium compound (Japan) Carlit: CIR-960, CIR-961), anthraquinone compounds (Nippon Kayaku: IR-750), aminium compounds (Nippon Kayaku: IRG-002, IRG-003, IRG-003K) , Polymethine compounds (Nippon Kayaku Co., Ltd .: IR-820B), dimonium Compounds (Nippon Kayaku Co., Ltd .: IRG-022, IRG-023), dianine compounds (Nippon Kayaku Co., Ltd .: CY-2, CY-4, CY-9), soluble phthalocyanine (Nippon Shokubai Co., Ltd .: TX-) 305A).

  Insoluble infrared absorbers for polyester resins include naphthalocyanine (Yamamoto Kasei Co., Ltd .: YKR5010, Sanyo Dye Co., Ltd .: Sample 1), inorganic materials (Shin-Etsu Chemical Co., Ltd .: Ytterbium UU-HP, Sumitomo Metals). (Manufactured by: Injumetin oxide) and the like.

Two or more of these infrared absorbers can be used in combination. Further, the combined use is effective because the infrared absorption region is widened and the fixing property is improved. The addition amount of the infrared absorber in the present invention is 0.05 to 5% by mass in the soluble type and 0.1 to 70 mass in the non-soluble type with respect to the finally produced toner. % Range is desirable. If the added amount exceeds 5% by mass and 70% by mass, respectively, the color may become cloudy and cannot be used.

In the toner production method of the present invention, a charge control agent and wax can be used as necessary.
As the charge control agent, known calixarene, nigrosine dyes, quaternary ammonium salts, amino group-containing polymers, metal-containing azo dyes, salicylic acid complex compounds, phenol compounds, azochromes, azozincs, and the like can be used. In addition, magnetic materials such as iron powder, magnetite, and ferrite can be mixed in the toner, and magnetic toner can be used. In particular, in the case of a color toner, white magnetic powder (for example, manufactured by Nippon Steel Mining Co., Ltd.) can be used.

  As the wax to be contained in the toner in the present invention, ester wax, polyethylene, polypropylene, or a copolymer of polyethylene and polypropylene is most preferable, but polyglycerin wax, microcrystalline wax, paraffin wax, carnauba wax, sazol wax, and montanic acid. Ester wax, deoxidized carnauba wax, palmitic acid, stearic acid, montanic acid, brandic acid, eleostearic acid, valinalic acid and other unsaturated fatty acids, stearic alcohol, aralkyl alcohol, behenyl alcohol, carnauvir alcohol, seryl alcohol, Saturated alcohols such as merisyl alcohol or long-chain alkyl alcohols having a long-chain alkyl group; polyhydric alcohols such as sorbitol Fatty acid amides such as linoleic acid amide, oleic acid amide, lauric acid amide; saturated fatty acid bisamides such as methylene bis stearic acid amide, ethylene biscapric acid amide, ethylene bis lauric acid amide, hexamethylene bis stearic acid amide, Unsaturated fatty acid amides such as ethylene bisoleic acid amide, hexamethylene bisoleic acid amide, N, N′-dioleyl adipic acid amide, N, N′-dioleyl sebacic acid amide; m-xylene bisstearic acid amide , N, N′-distearylisophthalic acid amides and other aromatic bisamides; fatty acid metal salts such as calcium stearate, calcium laurate, zinc stearate and magnesium stearate (generally referred to as metal soap); aliphatic Charcoal Waxes grafted with vinyl monomers such as styrene or acrylic acid on hydrogen wax; Fatty acid such as behenic acid monoglyceride and partially esterified product of polyhydric alcohol; Hydroxyl group obtained by hydrogenation of vegetable oil And methyl ester compounds having

As the wax used in the method for producing the toner of the present invention, a wax material showing an endothermic peak by DSC measurement (differential scanning calorimetry) at 50 to 90 ° C. is preferable. When the endothermic peak is lower than 50 ° C., the toner blocks, and when it is higher than 90 ° C., it may not contribute to fixing. In the DSC measurement, from the measurement principle, it is preferable to measure with a differential scanning calorimeter of high accuracy internal heat type input compensation type.
These waxes can be used alone or in combination of two or more.

  The toner production method of the present invention basically includes a step of preparing a toner composition by mixing the various toner components, and kneading and pulverizing the toner composition by melting and kneading, cooling, and pulverizing to obtain toner particles. It is a kneading and pulverizing method including steps. And the process which produces the said masterbatch is added to this kneading | pulverization grinding | pulverization method.

  Usually, in 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 mixed into a mixer such as a Henschel mixer or a ball mill. Infrared absorbers, antioxidants, pigments, dyes, magnetic materials, etc. while the resins are mixed with each other by melt-kneading using a heat kneader such as a heating roll, kneader, extruder, etc. A toner composition in which toner is dispersed or dissolved is prepared, and this is cooled and solidified, and then pulverized and classified to obtain a toner.

In the present invention, as described above, in order to improve the dispersibility of the infrared absorbent, the infrared absorbent is contained in a high concentration with respect to the polyolefin resin and / or the wax component in advance before the preparation of the toner composition. A master batch is prepared, and the master batch is mixed with other toner components other than the infrared absorbent to obtain a toner composition containing an infrared absorbent having a desired concentration.

  When a color toner for light fixing or an invisible toner is produced using the master batch, an infrared absorbent having a concentration of 60 times or more (preferably 60 to 270 times) of the infrared absorbent to be incorporated into the final toner is prepared. The master batch containing it will be prepared in advance.

In this invention, as resin which can be used for a masterbatch, the said wax can also be used other than polyolefin resin. A wax alone may be used. The production of a masterbatch using wax is advantageous because the exudation effect at the time of fixing the wax is promoted.
In addition, when mixing and using polyolefin resin and wax, it is preferable to make the mixing ratio ( polyolefin resin / wax) into the range of 100 / 0.01-100 / 5.

  The masterbatch can be produced by blending the infrared absorbent and the component containing the binder resin and / or wax so as to have the preferred ratio, and adopting various methods. Some of the embodiments will be exemplified below, but the present invention is not limited to the following methods as long as it does not contradict the gist of the present invention.

  For example, a method of melt-kneading an infrared absorbent and a component containing a binder resin and / or wax with a melt-kneader such as a 1-2 screw extruder, 3 rolls, a kneader, a Banbury mixer, and the infrared absorbent as a solvent in advance After being finely dispersed in a solvent, such as a sand mill, a colloid mill, or a ball mill, the solvent is removed while being melted and dissolved in the resin component and melt-kneaded with the melt-kneader. Examples thereof include a method of removing the solvent while adding to the resin component and melt-kneading with the melt-kneader.

  The master batch can be prepared not only by the above-described melt kneading method but also by a polymerization method. The method of finely dispersing the infrared absorber in a liquid material such as a polymerizable monomer or a solvent is, for example, a high-speed shearing disperser such as a homomixer, a biomixer or an Ebara milder, a colloid mill, a homomic line mill. Examples thereof include a grinding-type disperser such as a ball mill, a side grind mill, a pearl mill, and a media mill such as an attritor.

  Furthermore, the method for dispersing the binder resin or the like includes, for example, a roll mill, a kneader, a pressure kneader, a Banbury mixer, a lab plast mill, a uniaxial or biaxial kneading extruder, etc., and a binder resin and an infrared absorber. Can be melt-kneaded to finely disperse the infrared absorber in a solid material such as a binder resin.

The degree of the fine dispersion treatment of the infrared absorber depends on the type of polymerizable monomer, solvent, aqueous medium, resin, etc., to which the infrared absorber is added to perform the dispersion treatment. It is desirable that the particle size of the dispersed infrared absorber is about 0.5 μm or less, more preferably about 0.01 to 0.3 μm.
In this case, in order to obtain a dispersibility of a certain level or more, for example, the melt kneading conditions are preferably a pressure treatment using a Banbury mixer, an MS-type pressure kneader, or the like.

  As described above, the master batch in the present invention is obtained by dissolving or finely dispersing the infrared absorber in the matrix using the binder resin component or the like blended in the toner as a matrix. In the master batch, other additives that are mixed in a small amount in the same manner as the infrared absorber in the color toner for light fixing and the invisible toner to be finally produced, such as a wax component, a charge control agent, a colorant, etc. It is also possible to blend.

  In particular, as described above, if the colorant is also made into a master batch at the same time, it is possible to expect a color gamut increase and cost reduction effect. In this case, the content of the colorant is preferably in the range of 20 to 60% by mass and more preferably in the range of 30 to 50% by mass in the entire master batch.

  Also, the form of the masterbatch is not particularly limited, and any form such as a lump, powder, scale, pellet or the like can be taken, but preferably a powder, pellet or the like.

  Next, the prepared master batch and each of the above-described toner components are mixed to prepare a toner composition containing an infrared absorber having a final desired concentration.

  The blending amount of each toner component in the toner composition is such that when the masterbatch has a binder resin component or the like as its matrix, the toner batch has any amount when the binder resin component or the like is blended in the toner. It should be adjusted in consideration of whether such functions can be demonstrated. For example, when the binder resin component or the like functions as a binder resin, the total amount of the binder resin in the toner composition is naturally added as the binder resin component amount of the master batch and separately as a binder resin. This is the sum of the amount of resin to be added.

  The toner composition may be obtained by, for example, melt-kneading the master batch and other toner components in the same manner as described above, or a powdery master batch for use in melt-kneading in the next step; It may be a mixture with other toner components.

  In the method for producing the toner of the present invention, the apparatus used for melt-kneading the toner composition is not particularly limited, and examples thereof include a roll mill, a kneader, a pressure kneader, a Banbury mixer, a lab plast mill, A uniaxial or biaxial kneading extruder or the like can be used. Prior to such melt-kneading, it is also possible to provide a premixing step using a Henschel mixer, a supermixer, a V blender, a tumble blender, or the like as necessary.

  The melt-kneaded toner composition is cooled and then pulverized to form toner particles. The pulverization method is not particularly limited, and a known method can be used. For example, after crushing the melt-kneaded product, Micronizer, Ulmax, JET-O-mizer, KTM (krypton), It can be performed by a turbo me jet or the like. Furthermore, as a subsequent process, using a hybridization system (manufactured by Nara Machinery Co., Ltd.), a mechano-fusion system (manufactured by Hosokawa Micron Corporation), a kryptron system (manufactured by Kawasaki Heavy Industries, Ltd.), etc. The toner shape can be changed. In addition, spheronization with hot air can also be mentioned. Furthermore, the toner particle size distribution may be adjusted by classifying with an air classifier or the like.

  In the toner production method of the present invention as described above, since the master batch containing the infrared absorber is used as described above, the kneading process in a relatively short time or the kneading process in continuous production is performed. In addition, a uniform concentration distribution or dispersion distribution of the infrared absorber is achieved in the kneaded toner composition.

The toner obtained by the toner production method of the present invention preferably has 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 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, and it causes fogging and poor cleaning.

  The ratio of the volume average particle diameter Dv to the number average particle diameter D50p (D50v / D50p) is preferably in the range of 1.0 to 1.25. By using toner having a small particle size and a uniform particle size, variations in the charging performance of the toner are suppressed, fog in the formed image is reduced, and toner fixability is improved. Can be made. Further, fine line reproducibility and dot reproducibility in the formed image can be improved.

The average circularity of the toner of the present invention is preferably 0.955 or more, and more preferably 0.960 or more. Further, the standard deviation of the circularity is preferably 0.040 or less, and more preferably 0.038 or less. In this way, since each toner can be superposed on the recording medium in a dense state, the toner layer thickness on the recording medium can be reduced and the fixability can be improved. Further, by aligning the shape of the toner in this way, the fog, fine line reproducibility and dot reproducibility in the formed image are improved.
The average circularity of the toner is equal to the peripheral length (peripheral length) of the projected image of the toner particles and the projected area of the toner particles in a water dispersion system using a flow type particle image analyzer (manufactured by Simex, FPIA2000). The circumference of the circle (circle equivalent circumference) is obtained and calculated by (circle equivalent circumference / perimeter).

The toner in the present invention may be used by mixing white inorganic fine particles with toner particles for a fluidity improver or the like. The mixing ratio with the toner particles is in the range of 0.01 to 5 parts by mass, preferably in the range of 0.01 to 2.0 parts by mass, with respect to 100 parts by mass of the toner particles. Examples of such inorganic fine powder include silica fine powder, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite, and diatomaceous earth. Soil, chromium oxide, cerium oxide, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, silicon nitride and the like can be mentioned, and silica fine powder is particularly preferable. Moreover, well-known materials, such as a silica, titanium, resin fine powder, an alumina, can be used together. Further, as a cleaning activator, a metal salt of a higher fatty acid typified by zinc stearate and a fine powder of a fluorine-based high molecular weight substance may be added.
The toner in the present invention can be obtained by sufficiently mixing the inorganic fine particles and, if necessary, desired additives with a mixer such as a Henschel mixer.

  In addition, when adding an infrared absorber to the toner, it is added to the inside of the toner in the master batch, and at the same time, the infrared absorber is dispersed and added inside the color fixing toner or invisible toner, or the infrared absorber is added to the toner. It can be adhered or fixed to the surface of the fixing color toner or invisible toner.

  Examples of the surface modification apparatus for fixing the surface include a surfing system (manufactured by Nippon Pneumatic Industry Co., Ltd.), a hybridization system (manufactured by Nara Machinery Co., Ltd.), a kryptron cosmo series (manufactured by Kawasaki Heavy Industries, Ltd.), Application of dry mechanochemical methods such as surface reformer, mechanofusion system (manufactured by Hosokawa Micron Corporation), mechano mill (manufactured by Okada Seiko Co., Ltd.), etc. A surface modification device using a wet coating method such as a surface modification device, a disperse coat (manufactured by Nissin Engineering Co., Ltd.), or a coatmizer (manufactured by Freund Sangyo Co., Ltd.) can be used in appropriate combination.

  An electrophotographic developer containing a toner produced by the toner production method of the present invention (hereinafter sometimes abbreviated as “developer”) is a one-component developer comprising the toner, or a carrier and the toner. Any of the two-component developer comprising

  Examples of the carrier used as a two-component developer include a resin-coated carrier having a resin coating layer on the core material surface. As the core material, known magnetite, ferrite, and iron powder can be used. The carrier coating agent is not particularly limited, but a silicone resin system is particularly desirable.

  For example, when an electrophotographic photosensitive member is used as the electrostatic charge image bearing member, the image can be formed as follows. First, the surface of the electrophotographic photosensitive member is uniformly charged by a corotron charger, a contact charger or the like and then exposed to form an electrostatic charge image. Next, the toner particles are adhered to the electrostatic charge image by bringing the toner image into contact with or in proximity to a developing roll having a developer layer formed on the surface, thereby forming a toner image on the electrophotographic photosensitive member. The formed toner image is transferred onto the surface of a transfer medium such as paper using a corotron charger or the like. Further, the toner image transferred to the surface of the recording medium is fixed by a fixing device, and an image is formed on the recording medium.

As the electrophotographic photoreceptor, generally, an inorganic photoreceptor such as amorphous silicon or selenium, an organic photoreceptor using polysilane, phthalocyanine or the like as a charge generation material or a charge transport material can be used. Therefore, an amorphous silicon photoreceptor is preferable.
As the fixing device, a light fixing device (flash fixing device) is used when a color toner for light fixing is used, but in the case of invisible toner, a light fixing device, an oven fixing device, a hot roll fixing device is used. The vessel is not limited.

Examples of the light source used for the light fixing include a normal halogen lamp, a mercury lamp, a flash lamp, an infrared laser, and the like, and it is optimal because energy can be saved by fixing the flash lamp instantaneously. Preferably emission energy of the flash lamp is in the range of 1.0~7.0J / cm ^2, and more preferably in the range of 2~5J / 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 optical fixing method in the present invention is 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 conditions can be made mild and both void resistance and fixability can be achieved.
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 invention, 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, an example of an image forming apparatus provided with an optical fixing device using the optical fixing color toner obtained by the present invention 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.

  In FIG. 1, 1a to 1d are charging means, 2a to 2d are exposure means, 3a to 3d are electrostatic charge image carriers (photoconductors), 4a to 4d are developing means, 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 means (transfer rollers), 71 and 72 are rollers, Reference numeral 80 denotes a transfer voltage supply means, and 90 denotes a light fixing means.

  The image forming apparatus shown in FIG. 1 is disposed in contact with a recording sheet 10 and a developing unit for each color indicated by reference numerals 20, 30, 40, and 50 including a charging unit, an exposure unit, a photoconductor, and a developing unit. Rolls 71 and 72 for transporting the paper 10, transfer rolls 70a, 70b, 70c and 70d arranged so as to be in contact with the opposite side through the recording paper 10 so as to press the photoreceptor of each developing unit, Light for irradiating light to the side of the recording paper 10 that contacts the photoconductor of the recording paper 10 that passes through the nip portion between the photoconductor and the transfer roll in the direction of the arrow in the figure. And a fixing device 90.

  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 photoreceptor 3a in a clockwise direction. Further, the transfer roll 70a is opposed to the photosensitive member 3a through the recording paper 10 so as to come into contact with the surface of the photosensitive member 3a from the position where the developing unit 4a of the photosensitive member 3a is arranged until the charging unit 1a is arranged clockwise. Has been placed. Such a configuration is the same for the developing units of other colors. In the image forming apparatus of the present invention, the developer containing cyan toner is accommodated in the developing means 4a of the cyan developing unit 20, and the developing means of the other developing units have light fixing corresponding to each color. Toner is stored.

  Next, image formation using this image forming apparatus will be described. First, in the black developing unit 50, the surface of the photoreceptor 3d is uniformly charged by the charging unit 1d while rotating the photoreceptor 3d in the clockwise direction. Next, the surface of the charged 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 photoreceptor 3d. 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 photoreceptor of each developing unit.

  The toner images of the respective colors formed on the surface of the photoreceptor are sequentially transferred onto the recording paper 10 conveyed in the direction of the arrow by the action of the transfer potential by the transfer rolls 70a to 70d, and recorded so as to correspond to the original image information. A full-color laminated toner image is formed on the surface of the paper 10 and laminated in the order of cyan, magenta and yellow from the top layer.

  Next, the laminated toner image on the recording paper 10 is conveyed to the light fixing means 90, where it is irradiated with light from the light fixing means 80, melted, and light-fixed on the recording paper 10 to form a full-color image. It is formed.

The color toner for photofixation produced according to the present invention is suitably used for various applications such as newspapers, service bureaus, barcode printing, label printing, tag printing, Carlson method or ion flow method 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.
The invisible toner produced according to the present invention is often fixed by a heat roll, but can also be fixed by flash fixing. Mainly used for printing confidential information with visible printing.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. In the following, “%” and “part” mean “% by mass” and “part by mass” unless otherwise specified.

<Manufacture of color toner for light fixing>
(Examples 2 to 5 and Example 7, Comparative Examples 1 to 9)
-Preparation of master batch-
According to each composition shown in Table 1, toner components having a total mass of 10 kg were sufficiently mixed with a Henschel mixer, and then melt kneaded at 150 ° C. for 20 minutes using an MS type pressure kneader (manufactured by Moriyama). Next, the kneaded product was cooled and pulverized to 1 mm or less with a coarse pulverizer to obtain master batches M-1 to M-15.
When the slices of this master batch were observed with a microscope, infrared absorber domains each having an outer diameter of about 0.5 μm were confirmed.

-Manufacture of color toner for light fixing-
In accordance with the composition of each Example and Comparative Example shown in Table 2, each 5 kg of a toner composition containing only the above-mentioned master batch and other toner components excluding external additives, or a composition comprising only a toner component not containing a master batch After being sufficiently mixed with a Henschel mixer, they were continuously fed to a twin-screw extruder (PCM-30, manufactured by Ikegai Co., Ltd.) and melt-kneaded. The melt-kneaded product of the toner composition was cooled, coarsely pulverized, and further finely pulverized with a jet mill.

The obtained finely pulverized product was classified with an air classifier to obtain toner particles having a volume average particle size in the range of 6.0 to 6.5 μm and an average circularity of 0.955 to 0.957. To each toner particle, hydrophobic silica TG820F (manufactured by Cabot) is added so as to be 0.5%, and uniformly mixed with a Henschel mixer, and color toners for photofixing T-0 to T-2, T-4 to T- 13 and T-15 were obtained.

<Evaluation of color toner for light fixing>
-Production of developer-
A two-component developer was prepared using the toners T-0 to T-2, T-4 to T-13 and T-15 obtained in Examples 2 to 5 and 7, and Comparative Examples 1 to 9. . As a carrier to be mixed with each toner, a carrier having a general-purpose volume average particle diameter of 60 μm coated with a silicone resin was used. 94 parts of a carrier was mixed with 6 parts of each toner, and mixed for 2 hours with a 10 L ball mill to prepare 7 kg of each developer. The toner thus obtained was evaluated for fixability and color reproducibility by the following methods.

(Fixability evaluation)
-Fixability-
Using each of the developers described above, image evaluation including fixability was performed. As an evaluation apparatus, a DocuPrint 1100CF remodeling machine manufactured by Fuji Xerox Co., Ltd. (schematic configuration is the same as in FIG. 1) equipped with a xenon flash lamp having a high emission intensity in the wavelength range of 700 to 1500 nm as a light fixing device was used. The flash light emission method is a delay light emission method in which light emission per unit area is performed twice. As the delayed light emission, the same light energy was irradiated twice, and the delay time was set to 5 msec.

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, T-0 to T-14 cyan toner as shown in Table 2 and magenta, yellow, and black light fixing color toners were used, respectively, and the toner adhesion amount (the amount of toner on the recording medium) the amount) of the image reproduction was carried out adjusted to 1.8 mg / cm ² at 1.2mg / cm ^2, 3 primary color at 0.6mg / cm ^{2, 2} primary color monochromatic.

  In the above magenta, yellow and black toners, only the cyan pigment in each formulation of T-0 to T-14 in Table 2 is a magenta pigment (Pigment Violet 19, trade name: Hostaperm Red E2B70 (manufactured by Clariant)). The above image was prepared in the same manner except that the pigment was changed to yellow pigment (Pigment Yellow 185, trade name: Paliotol Y-D1155 (manufactured by BASF)), carbon black (trade name: Nipex 35 (manufactured by Degussa)). These are used as a set for the forming apparatus (the following evaluation results are also abbreviated as T-0 to T-14).

The fixing ratio of the obtained 1 inch square image was evaluated as follows. First, the optical density (OD1) of the image is measured, and then an adhesive tape (Scotch Mending Tape, manufactured by Sumitomo 3M) is applied to the image, and then the adhesive tape is peeled off. The concentration (OD2) was measured. The optical density was measured using a spectrocolorimeter manufactured by X-rite, X-rite 938, under conditions of a light source D50 and 2 ° (backing white). The fixing rate was calculated from the following formula (2) using the obtained optical density value.
Fixing rate (%) = (OD2 / OD1) × 100 (2)

The formed image was visually observed, and it was confirmed that good image quality with little background stain such as fogging was obtained. The obtained fixing rate is good if it is 80% or more, and can be used if it is 70% or more. The fixing rate stability was evaluated according to the following criteria.
A: The fixing rate is 90% or more.
A: The fixing rate is 80% or more and less than 90%.
X: Fixing rate is less than 80%.
Incidentally, the status A density was used as the optical density of the color toner.

(Color reproducibility evaluation)
Regarding the color reproducibility, in the above-described full-color image forming apparatus, each toner is sufficiently mixed and the color reproducibility of the image is good, ◯, the case where the color mixing is somewhat insufficient but there is no practical problem, Δ The case where the color mixture of each toner was insufficient and the desired color reproduction was not performed and there was a problem in practical use was evaluated as x.
The results are summarized in Table 3.

  FIG. 2 shows the fixing ratio shown in Table 3 in relation to the concentration of the infrared absorbent in the master batch. As shown in the figure, the solubility infrared is higher than that of the non-soluble infrared absorbent. In the case of the absorbent, it can be seen that even when the concentration in the master batch is low, the fixing rate is improved at an early stage, and a stable fixing property can be obtained at a wider concentration.

<Manufacture of invisible toner>
( Reference Examples 8-13, Reference Comparative Examples 10-11)
Each master batch S-1 to S-7 as shown in Table 4 was prepared in the same manner as in the production of the color toner for light fixing, and each reference example as shown in Table 5 was similarly used using these. According to the composition of the reference comparative example, toner particles having a volume average particle diameter in the range of 6.0 to 6.5 μm and an average circularity in the range of 0.955 to 0.957 were obtained. Hydrophobic silica TG820F (manufactured by Cabot) was added to each of these toner particles so as to be 0.5% and uniformly mixed with a Henschel mixer to obtain invisible toners ST-0 to ST-7.

<Evaluation of invisible toner>
Next, using the obtained toner and plain paper as a recording medium, an invisible image (bar code) was formed by an image forming apparatus capable of heat fixing. The image forming apparatus used is an image forming apparatus (manufactured by Fuji Xerox, Documentent 402FS) provided with a heat roller as a heat fixing device. When the area where the barcode of the paper was formed was visually observed, almost no coloring was observed, and it was almost transparent.

  Readability of the barcode is as follows: THLS-6000 & TBR-6000 manufactured by Token Co., Ltd. (using a 780 nm laser as the light source) as a barcode reader, infrared light emitting diode (GL480, manufactured by Sharp Corporation, peak emission wavelength 950 nm) ) Using a photodiode (manufactured by Sharp Corporation, PD413PI, peak emission wavelength 960 nm) as the light receiving portion, the barcode readability was determined.

The determination was performed by the reading test using the above bar code reader and based on the following criteria.
A: Reading was possible 100 times or more.
○: The number of readable times was 10 times or more and less than 100 times.
X: The number of possible readings was less than 10.
The results are summarized in Table 6.

As shown in the results of Table 3, the color toner for photofixation according to the present invention using a masterbatch containing a certain amount of infrared absorber has a fixability as compared with that without using such a masterbatch. It was found that the color reproducibility was clearly superior. Further, as shown in the results of Table 6, the non-visible toner using a masterbatch containing an amount of the infrared absorbing agent in a certain range, it was found that stable barcode read.

1 is a schematic configuration diagram illustrating an example of an image forming apparatus using toner obtained according to the present invention. FIG. 3 is a graph showing a relationship of a fixing rate with respect to a master batch density (infrared absorbent) of a toner obtained by the present invention.

Explanation of symbols

1a, 1b, 1c, 1d Charging means 2a, 2b, 2c, 2d Exposure means 3a, 3b, 3c, 3d Photoconductors 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 (4)

A method for producing a color toner for photofixing comprising at least a polyolefin resin, a colorant, and a diimonium compound having a turbidity of less than 25% when added to the polyolefin resin,
Step of preparing a master batch which contains previously polyolefin resin and / or the diimmonium compound to component containing a wax at a concentration ranging from 50 to 80 wt%, the master batch was mixed with the other toner components And a kneading and pulverizing step in which the toner composition is melt-kneaded, cooled, and then pulverized to form toner particles. Toner manufacturing method. Wherein in the step of preparing the master batch, relative to component comprising a polyolefin resin and / or wax contain a colorant together with the diimmonium compound, in the step of preparing the toner composition, admixing the other toner ingredients The method for producing a color toner for photofixing according to claim 1. A method for producing a color toner for photofixing comprising at least a polyolefin resin, a colorant and a naphthalocyanine compound having a turbidity of 25% or more when added to the polyolefin resin,
A step of preparing a masterbatch containing a naphthalocyanine compound in a concentration of 40 to 80% by mass with respect to a component containing a polyolefin resin and / or wax in advance, and mixing the masterbatch with other toner components And a step of preparing a toner composition containing a naphthalocyanine compound at a desired concentration, and a kneading and pulverizing step of melting and kneading and cooling the toner composition to form toner particles. Manufacturing method of color toner. In the step of producing the master batch, relative to component comprising a polyolefin resin and / or wax contain a colorant with the naphthalocyanine compound, in the step of preparing the toner composition, admixing the other toner ingredients The method for producing a color toner for photofixing according to claim 3.

Images