JP2006078888A - Toner for electrostatically charged image development, toner for light fixation, and invisible toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide toner for electrostatically charged image development which is free of deterioration of a contained infrared-ray absorber even when left as it is for a long period and further to provide toner for light fixation which varies in neither charging properly nor fixing properly even when left as it is for a long period and invisible toner that makes it possible to read a signal of infrared rays for a long period when an image is formed as an invisible image. <P>SOLUTION: Disclosed is the toner for electrostatically charged image development which contains at least binding resin and the infrared-ray absorber, the toner for electrostatically charged image development containing copper-containing phenolate as an antioxidant agent together with the infrared-ray absorber. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electrostatic image developing toner that can be used in an electrophotographic copying machine, an electrophotographic printer, a FAX, a printer, and the like. More specifically, the present invention relates to light fixing for fixing to recording paper by light fixing, and a toner for light fixing and invisible toner used for forming an invisible image on which an invisible signal is recorded.

  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 that gives a positive or negative uniform electrostatic charge to the photoconductive insulator surface of the photosensitive drum, the surface of the insulator is irradiated with, for example, a laser beam, and the electrostatic charge on the insulator surface is reduced. An electrostatic latent image corresponding to image information is formed by partially erasing. Next, fine powder of a developer called toner (electrostatic image developing toner) is attached to the latent image portion on which the electrostatic charge remains on the photoconductive insulator, for example, 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 may or may not be visually recognized, and an infrared absorption pattern is formed on the surface of the recording medium. The invisible image has an information pattern having some specific information such as personal information, or a detection mark. Such a non-information pattern can be given 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.

  However, it is known that an infrared absorbent, particularly an infrared absorbent dissolved in a resin, deactivates its ability to absorb infrared rays over time due to air oxidation. Accordingly, there are problems that the color toner is not fixed in the light fixing over time, and that the cipher described with the invisible toner using infrared rays as a signal cannot be read.

Addition of an antioxidant may be considered for oxidative degradation. However, conventionally, studies have been made to add an antioxidant to a general-purpose toner (see, for example, Patent Documents 11 to 13), but studies have been made on a light fixing toner and an invisible toner aimed at preventing oxidation of an infrared absorber. Absent. Therefore, the present situation is that the effect of extending the life of the infrared absorber cannot be obtained by simply adding an antioxidant.
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 JP-A-4-212172 Japanese Unexamined Patent Publication No. Hei 4-2822641 JP-A-4-284460

The object of the present invention is to solve the above-mentioned problems of the prior art.
That is, an object of the present invention is to provide a toner for developing an electrostatic charge image in which the contained infrared absorber does not deteriorate even when left for a long period of time. It is another object of the present invention to provide a toner for photofixing that does not change in charging property and fixability even when left for a long time, and an invisible toner that can read an infrared signal for a long time when formed as an invisible image. .

The above-mentioned subject is achieved by the following present invention. That is, the present invention
<1> An electrostatic charge image developing toner comprising at least a binder resin and an infrared absorbent, wherein the toner comprises an infrared absorbent and copper-containing phenolate as an antioxidant. It is.

<2> The antioxidant is bis (4-t-butyl-1,2-dithiophenolate) copper-tetra-n-butylammonium and / or bis (4-morpholinosulfenyl-1,2-dithio The toner for developing an electrostatic charge image according to <1>, which is phenolate) copper-tetra-n-butylammonium.

<3> The electrostatic image developing toner according to <1> or <2>, wherein the infrared absorbent is dissolved in the binder resin.

<4> A toner for photofixing, wherein the toner for developing an electrostatic charge image according to any one of <1> to <3> is used.

<5> An invisible toner using the electrostatic image developing toner according to any one of <1> to <3>.

  According to the present invention, it is possible to obtain a toner for developing an electrostatic charge image that does not deteriorate the infrared absorbent even when left for a long period of time. In addition, it is possible to provide a light fixing toner that does not change fixing property and an invisible toner that can read an infrared signal for a long time when formed as an invisible image.

Hereinafter, the present invention will be described in detail.
The toner for developing an electrostatic charge image of the present invention includes at least a binder resin and an infrared absorber, and includes a copper-containing phenolate as an antioxidant together with the infrared absorber. The toner for photofixing and the invisible toner of the present invention are characterized by using the toner for developing an electrostatic image of the present invention.

  The toner for developing an electrostatic charge image of the present invention can be used for both a one-component developer and a two-component developer, and its use is not particularly limited. However, the toner for developing an electrostatic charge image of the present invention contains an infrared absorber, and when used as a light fixing toner or an invisible toner, the effect thereof is exhibited to a great extent. Therefore, the toner for developing an electrostatic charge image of the present invention will be described below by using the photofixing toner and the invisible toner of the present invention.

Here, the invisible toner is a toner for deciphering using invisible light such as infrared rays, and includes a case where it can be visually recognized when fixed as a toner image on paper or the like, and can be recognized visually. The toner does not have to be, and 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. Even if the colorant is added in an amount of 1% by mass or less at which the presence of the colorant is clearly not confirmed, it can be called an invisible toner. Therefore, the constitution of the invisible toner is basically similar to the constitution of the photofixing toner except that it does not contain a colorant. Therefore, hereinafter, the photofixing toner and the invisible toner in the present invention (hereinafter, these are combined). The invisible toner of the present invention includes an invisible toner that is photofixed.

  As described above, in the photofixing toner containing the infrared absorber, the infrared absorber is deactivated with the passage of time, and in particular, the color toner cannot sufficiently absorb light in the photofixing, resulting in poor fixing. End up. Further, with invisible toner, the invisible image after fixing is left unattended or information cannot be read due to repeated information reading.

  As a result of diligent research by the present inventors, in a toner for photofixing containing at least an infrared absorber, a specific antioxidant (copper-containing phenolate) suitable for the infrared absorber is added to the toner, so that time is increased. By obtaining a photo-fixing toner that does not change its fixability and chargeability even after elapse of time, and by adding a specific antioxidant suitable for the infrared absorber to the toner in an invisible toner having at least an infrared absorber. It has been found that it is possible to read a cipher printed with invisible toner for a long time.

  That is, for the toner of the present invention, a specific infrared absorber is used as described later for adaptability to a xenon flash lamp or an information reading detection device in photofixing. It is not clear what kind of antioxidants are effective for stabilizing the infrared absorption capacity over the range, and it is effective for infrared absorbers dispersed in binder resin like toner. It was also unclear as to whether antioxidants could act.

  The present inventors examined how an effective infrared absorber in the toner is dispersed or dissolved in the binder resin, and selected a specific antioxidant in consideration of this dispersed / dissolved state. Thus, the present inventors have found that the stability of the infrared absorber can be greatly improved by adding the azo compound, and the present invention has been completed.

Hereinafter, the configuration of the toner of the present invention will be described.
For the toner in the present invention, known binder resins and various colorants can be used. The main component of the binder resin is preferably polyester or polyolefin, but a copolymer of styrene and acrylic acid or methacrylic acid, polyvinyl chloride, phenol resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester. Resin, polyurethane, polyamide resin, furan resin, epoxy resin, xylene resin, polyvinyl butyral, terpene resin, coumarone indene resin, petroleum resin, polyether polyol resin, and the like can be used alone or in combination. From the viewpoints of durability and translucency, it is preferable to use a polyester resin or a norbornene 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.

Further, the colorant of the photofixing toner of the present invention can be appropriately selected and used according 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, 14, 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 Magenta dyes such as 35, 36, 37, 38, 39, 40, etc., Bengala, cadmium red, red lead, mercury sulfide, cadmium, permanent red 4R, risol 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 light fixing toner of the present invention includes black toner mixed with yellow, magenta, cyan, red, green and blue pigments.

  The addition amount of each colorant in the photofixing toner of the present invention is preferably in the range of 1 to 20 parts by mass in 100 parts by mass of toner particles prepared by mixing with a binder resin or the like.

  On the other hand, for the invisible toner of the present invention, the colorant as described above is not used. 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 addition, the infrared absorber added to the toner in the present invention 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. Can also 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 present invention, as described above, an antioxidant suitable for the infrared absorber is selected depending on the solubility of the infrared absorber in the binder resin. Regarding the solubility in this binder resin, the case where the turbidity when added to the binder resin using an infrared absorber is less than 25% is judged as a “soluble infrared absorber”, and the turbidity is 25. % Or more was judged as “insoluble (dispersible) 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, 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 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).

  Examples of insoluble (dispersible) 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, manufactured by Sumitomo Metals Co., Ltd .: indium tin oxide) and the like.

  Among these infrared absorbers, as the infrared absorber used in the photofixing toner of the present invention, the soluble infrared absorber such as aminium, diimonium-based infrared absorber, cyanine-based infrared absorber, and the like are used. It is preferable from the viewpoint of safety and color tone. The nickel complex is preferable as a color tone, but has high toxicity such as carcinogenicity, and is most preferably not added to the toner.

  On the other hand, as the infrared absorber contained in the invisible toner of the present invention, the soluble infrared absorber such as aminium, diimonium-based infrared absorber, cyanine-based infrared absorber and the like are preferable from the viewpoint of environmental safety and color tone.

  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. In the present invention, the addition amount of the infrared absorber is in the range of 0.05 to 2 parts by mass with respect to 100 parts by mass of the toner, and 0.1 to 50 with respect to the insoluble (dispersibility) type. A range of parts by mass is desirable.

To the toner of the present invention, copper-containing phenolate as an antioxidant is added to prevent the infrared absorber from being deactivated by being left.
Regarding the action of the antioxidant, an infrared absorbent that is insoluble in the above-mentioned resin is relatively strong against oxidation, so that the addition of an antioxidant has little effect. On the other hand, soluble infrared absorbers are susceptible to oxidation, so the addition of an antioxidant can greatly increase the long-term stability of the infrared absorber. From such a viewpoint, as a result of studying with particular attention to enhancing the antioxidant against the soluble infrared absorber, copper-containing phenolate is effective as an antioxidant for the infrared absorber. It was found. This is considered to be because the necessary infrared absorber dispersed (dissolved) in the binder resin to a minute size can be protected by being easily oxidized with copper-containing phenolate.

Examples of the copper-containing phenolate include bis (4-t-butyl-1,2-dithiophenolate) copper-tetra-n-butylammonium and / or bis (4-morpholinosulfenyl-1,2- Dithiophenolate) copper-tetra-n-butylammonium is most effective.
In this case, as the infrared absorber combined with the copper-containing phenolate, diimonium and cyanine are preferable in the case of a photofixing toner, and diimonium and cyanine are particularly preferable in the case of an invisible toner.

  On the other hand, among the antioxidants, ammonium such as bis (1,2-dithiophenolate) nickel-tetra-n-butylammonium salt and bis (1-mercaptolate-2-naphtholate) platinum-tetra-n-butylammonium. Since the compound is not easily oxidized, it does not serve as a protective agent for the infrared absorber.

  The antioxidant contained together with the infrared absorber may be added to the inside of the toner, and may be externally attached or externally fixed. In general, it is considered that the most effective is the addition to the inside, but since the infrared absorber becomes a toner fracture surface at the time of toner pulverization and becomes a high concentration on the toner surface, the antioxidant is attached to the outside or externally. It also has an effect by fixing.

  In addition, the infrared absorbing agent soluble in the binder resin appears to have a higher infrared absorbing ability when added in the same amount immediately after production than the non-solvent infrared absorbing agent. In particular, the antioxidant contained together with the infrared absorber exhibits an effect because the absorption capacity is quickly deactivated.

  In the present invention, the addition amount of the antioxidant varies depending on the kind of the binder resin and the infrared absorber, but is in the range of 0.01 to 5 parts by mass with respect to 100 parts by mass of the toner in both internal addition and external addition. Is preferable, and the range of 0.1 to 2 parts by mass is more preferable.

In addition, a charge control agent and wax may be added to the toner of the present invention 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 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 onto vinyl waxes using vinyl monomers such as styrene and acrylic acid; Fatty acids such as behenic acid monoglycerides and partially esterified products of polyhydric alcohols; Hydroxyl groups obtained by hydrogenation of vegetable oils and fats And methyl ester compounds having

  As the wax used for the toner, a wax material having 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.

  In producing each toner as described above, a commonly used kneading and pulverizing method, wet granulation method, or 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 prepare the toner of the present invention 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 or an infrared absorber, you may perform a masterbatch.

Furthermore, when adding an infrared absorber to the toner, in addition to dispersing the infrared absorber in the color fixing toner or invisible toner and adding it as described above, an infrared absorber or an antioxidant is used for the optical fixing. It can be adhered or fixed to the surface of color toner or invisible toner.
Examples of the surface modification device for fixing the surface include a surfing system (manufactured by Nippon Pneumatic Kogyo Co., Ltd.), a hybridization system (manufactured by Nara Machinery Co., Ltd.), a kryptron cosmo series (manufactured by Kawasaki Heavy Industries, Ltd.), Surface reformer that gives impacts in high-speed air currents such as Inomizer System (Hosokawa Micron); Applied dry mechanochemical methods such as Mechano Fusion System (Hosokawa Micron), Mechano Mill (Okada Seiko) A surface modification device using a wet coating method of Disper Coat (manufactured by Nisshin Engineering Co., Ltd.), Coat Mizer (manufactured by Freund Sangyo Co., Ltd.), and the like can be used in appropriate combination.

  The toner of the present invention produced as described above preferably has a volume average particle diameter D50v of 3 to 10 μm, and more preferably 4 to 8 μm. 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).

On the other hand, when toner particles are produced by the wet granulation method, the shape factor SF1 of the toner particles is preferably in the range of 110 to 135.
The toner shape factor SF1 is obtained by taking toner particles dispersed on a slide glass or an optical microscope image of the toner into a Luzex image analyzer through a video camera, and obtaining the maximum length and projected area of 50 or more toners. It is obtained by calculating by (1) and obtaining the average value.
SF1 = (ML ² / A) × (π / 4) × 100 (1)
In the above formula (1), ML represents the absolute maximum length of the toner particles, and A represents the projected area of the toner particles.

The volume particle size distribution index GSDv of the toner particles is preferably 1.25 or less.
In the present invention, the toner volume average particle size, the particle size distribution index, and the like were measured using a Coulter Counter TAII (manufactured by Beckman-Coulter) and the electrolyte using ISOTON-II (manufactured by Beckman-Coulter).

  For the divided particle size range (channel), the measured particle size distribution is drawn from the smaller diameter side for each volume and number, and the particle size that becomes 16% cumulative is the volume average particle size D16v and the number average particle size. D16p is defined, and the particle size that is 50% cumulative is defined as the volume average particle size D50v (the volume average particle size of the toner described above indicates this) and the number average particle size D50p. Similarly, the particle size that is 84% cumulative is defined as the volume average particle size D84v and the number average particle size D84p. Using these, the volume average particle size distribution index (GSDv) is calculated as D84v / D16v.

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 are 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.

Next, an image forming method and an image forming apparatus using the toner of the present invention will be described.
In the image forming method using the toner of the present invention, the electrophotographic developer (hereinafter sometimes abbreviated as “developer”) is composed of a one-component developer composed of the toner, or a carrier and the toner. Any of two-component developers may be used.

  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.

  An example of an image forming method in which the toner of the present invention is used includes a step of forming an electrostatic charge image on the surface of the electrostatic charge image carrier, and an electrostatic charge image formed on the surface of the electrostatic charge image carrier. A step of developing with a developer to form a toner image, a transfer step of transferring the toner image formed on the surface of the electrostatic charge image carrier to the surface of the transfer target, and a toner image transferred to the surface of the record of the target And a fixing step of fixing on the surface of the recording medium and forming an image. At this time, as the developer, the developer containing the above-described light fixing toner or invisible toner is used.

  Each of the above steps can be performed by a known method employed in a conventional image forming method. In the case where an intermediate transfer member or the like is not used as the transfer member, the transfer member becomes a recording medium as it is. Furthermore, the image forming method of the present invention may include steps other than the above-described steps such as a cleaning step of cleaning the surface of the latent image carrier.

  Image formation by the image forming method of the present invention can be performed, for example, as follows when an electrophotographic photosensitive member is used as the electrostatic charge image carrier. 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.
Further, as the fixing device, a light fixing device (flash fixing device) is used when a light fixing toner is used, but in the case of an invisible toner, a light fixing device, an oven fixing device, a heat roll fixing device. It 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 (2).
S = ((1/2) × C × V ² ) / (u × L) × (n × f) (2)
In the above formula (2), 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 transport 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 by one light emission, so that the fixing condition can be made mild, and both void resistance and fixing property 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 0-20, 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 including an optical fixing device using the toner of 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, whereby 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 each color toner image is formed on the surface of the photosensitive member of the 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.

Hereinafter, the present invention will be described specifically by way of examples.
(1) Production of toner (production of toner particles by kneading and pulverization method)
A toner composition composed of each binder resin (binder resin), infrared absorber, antioxidant, pigment, charge control agent, and wax as shown in Table 1 was put into a Henschel mixer, and premixed. Then, melt-kneaded at 100-110 ° C. and 250 rpm with an extruder (Ikegai Co., Ltd., PCM-30), then coarsely pulverized with a hammer mill, finely pulverized with a jet mill, and then classified with an airflow classifier. The toner particles to be the toners (CT-1 to 8, MT-1, YT-1, ST-1 to 2) having the characteristics shown in Table 2 were obtained.

(Manufacture of toner particles by wet polymerization method)
-Preparation of resin fine particle dispersion-
-Styrene (Wako Pure Chemical Industries): 325 parts by mass-n-butyl acrylate (Wako Pure Chemical Industries): 75 parts by mass-β-carboxyethyl acrylate (Rhodia Nikka): 9 parts by mass-1'-10-decanediol di Acrylate (manufactured by Shin-Nakamura Chemical): 1.5 parts by mass / dodecanethiol (manufactured by Wako Pure Chemical Industries): 2.7 parts by mass

A raw material solution obtained by mixing and dissolving the above components was prepared. To a flask filled with 4 parts by weight of an anionic surfactant (Dowfax, Rhodia) with an aqueous solution in which 550 parts by weight of ion-exchanged water was dissolved, 413.2 parts by weight of the raw material solution was gradually added to the flask. Disperse and emulsify, add 50 parts by mass of ion-exchanged water in which 6 parts by mass of ammonium persulfate has been dissolved while slowly stirring and mixing for 10 minutes. While stirring, the solution in the flask was heated to 70 ° C. with an oil bath, and emulsion polymerization was continued for 5 hours to obtain an anionic resin fine particle dispersion.
The obtained resin fine particles had a center particle size of 196 nm, a solid content of 40% by mass, a glass transition point of 51.5 ° C., and a weight molecular weight Mw of 32400.

-Preparation of infrared absorber dispersion-
Infrared absorber (diimonium, NIR-IM1, manufactured by Nagase ChemteX Corporation): 0.5 parts by mass Tetramethylethylenediamine: 0.4 parts by mass Ionic surfactant (Neogen RK, manufactured by Daiichi Kogyo Seiyaku) ): 5 parts by mass, ion-exchanged water: 195 parts by mass, antioxidant 1 (Sumitomo Seika Co., Ltd.): 0.5 parts by mass The above components were mixed and dissolved, and then homogenizer (Ultra Turrax manufactured by IKA) was used. The dispersion was carried out for 10 minutes to obtain an infrared absorbent dispersion (containing an antioxidant) having a center particle diameter of 121 nm.

-Preparation of release agent dispersion-
-Polyethylene wax (PW725, manufactured by Toyo Petrolite): 45 parts by mass-Ionic surfactant (Neogen RK, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): 5 parts by mass-Ion-exchanged water: 200 parts by mass After mixing and heating to 130 ° C., the mixture was dispersed with a gorin homogenizer (manufactured by Gorin) under a pressure of 150 kg / cm ² for 15 minutes and cooled to room temperature to obtain a release agent dispersion having a center particle size of 180 nm.

-Production of toner particles-
Next, a toner was prepared using the obtained various dispersions as follows.
・ Resin fine particle dispersion: 80 parts by mass (solid content: 40 parts by mass)
Infrared absorbent dispersion: 100 parts by mass (infrared absorbent: about 0.25 parts by mass, antioxidant: 0.25 parts by mass)
Release agent dispersion: 50 parts by mass (solid content: 10 parts by mass)
The above components were sufficiently mixed and dispersed with Ultra Turrax (IKA, T50) in a round stainless steel flask.

  Next, 0.4 parts by mass of polyaluminum chloride was added thereto, and the dispersion operation was continued with an ultra turrax. The flask was heated to 49 ° C. with stirring in an oil bath for heating, and maintained at 49 ° C. for 60 minutes, and then 31 parts by mass of the resin fine particle dispersion was gradually added. Then, after adjusting the pH of the solution in the flask to 5.4 with a 0.5 mol / liter sodium hydroxide aqueous solution, the stainless steel flask was sealed and heated to 96 ° C. while continuing stirring using a magnetic seal. And held for 5 hours.

  After completion of the reaction, the mixture was cooled, filtered, sufficiently washed with ion exchange water, and then subjected to solid-liquid separation by Nutsche suction filtration. This was further redispersed in 3 liters of ion exchange water at 40 ° C., and stirred and washed at 300 rpm for 15 minutes. This was repeated five more times, and when the pH of the filtrate reached 7.01, solid-liquid separation was performed using No5A filter paper by Nutsche suction filtration. Next, vacuum drying was continued for 12 hours to obtain toner particles.

(Production of toner)
Next, 0.5 parts by mass of hydrophobic silica fine particles (TG820F) are added to 100 parts by mass of each toner particle (and 1 part by mass of an antioxidant depending on the toner), and an external addition process is performed using a Henschel mixer. Each toner (CT-1 to 8, MT-1, YT-1, ST-1 to 3) as shown in Table 1 was obtained.
Table 2 summarizes the characteristics of each toner. CT-1 to CT-3, CT-8, MT-1, YT-1, and ST-2 to 3 are antioxidants added to the inside of the toner, and CT-5 to 7 are antioxidants added to the toner. It is attached to the surface.

(2) Manufacture of developer 6 parts by mass of each of the above-mentioned toners per 94 parts by mass of a carrier (powdertech, DC27) having a volume average particle diameter of 60 μm coated with a cross-linked fluorine-modified silicone resin on the surface of a ferrite core material Partly added and mixed for 2 hours in a 10 L ball mill to prepare 7 kg of each two-component developer.

(3) Evaluation (Evaluation of photofixing toner)
-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, as shown in Table 3, as examples and comparative examples, cyan, magenta, and yellow light fixing color toners are used, respectively, and the toner adhesion amount (toner applied amount on the recording medium) is a single color. The image was taken out by adjusting to 0.6 mg / cm ² .

  On the other hand, each photofixing color toner used in each example and comparative example was left in an 80% oxygen concentration atmosphere for 2 months to perform an oxidation acceleration test (storage) of the toner. The toner was imaged under the same conditions as described above.

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 (3) using the obtained optical density value.
Fixing rate (%) = (OD2 / OD1) × 100 (3)

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 difference in the fixing rate between the initial stage and after storage is less than 20%.
(Triangle | delta): The difference of the fixing rate after an initial stage and storage is 20% or more and less than 30%.
X: The difference in the fixing rate between the initial stage and after storage is 30% or more.
Incidentally, the status A density was used as the optical density of the color toner.

-Toner chargeability-
Each developer produced using the photofixing toners of Examples and Comparative Examples shown in Table 3 was left for 1 day and night in a normal temperature and humidity environment (temperature: 22 ° C., humidity: 55% RH). Then, each was mixed and stirred for 60 minutes with a Turbula stirrer, and the charge amount was measured by a blow-off method with a charge amount measuring device (TB200, manufactured by Toshiba Corporation). Similarly, the charge amount of the toner subjected to the oxidation acceleration test was measured.

The charge amount is good if it is 15 μC / g or more, but the charge amount stability was evaluated according to the following criteria.
A: The difference in charge amount between the initial stage and after storage is less than 5 μC / g.
(Triangle | delta): The difference of the charge amount of an initial stage and after a preservation | save is 5 to less than 10 microC / g.
X: The difference in the charge amount between the initial stage and after storage is 10 μC / g or more.
The results are summarized in Table 3.

(Evaluation of invisible toner)
A developer using the invisible toner shown in the examples and comparative examples in Table 4 is loaded into an image forming apparatus (Fuji Xerox, Documentent 402FS) capable of heat fixing using plain paper as a sheet, and an invisible image (barcode). ) Was formed. The image forming apparatus used is an image forming apparatus 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.
In addition, each invisible image produced in each of the above examples and comparative examples was left in an 80% oxygen concentration atmosphere for 2 months to conduct an oxidation acceleration test of the image, and an invisible image (barcode) after being left was obtained.

  The readability of each invisible image (barcode) is determined by using THLS-6000 & TBR-6000 (using a 780 nm laser as a light source) as a barcode reader and an infrared light emitting diode (Sharp) as a light source. Barcode reading performance was determined using a photodiode (manufactured by Sharp Corporation, PD413PI, peak emission wavelength 960 nm) as a light receiving part.

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 20 times or more and less than 100 times.
X: The number of readable times was less than 20.

The number of readings is 20 or more, which is a satisfactory level, but reading stability was evaluated according to the following criteria.
○: The difference in the number of readings after storage is 20 times or more.
X: The difference in the number of readings after storage is less than 20 times.
The results are summarized in Table 4.

   As shown in the results of Table 3, in the photofixing toner of the present invention containing a specific antioxidant (copper-containing phenolate), fixability and charge even after the accelerated oxidation test were compared with those not containing the antioxidant. It was found that sex did not change greatly. Further, as shown in the results of Table 4, it was found that when the invisible toner of the present invention containing a specific antioxidant is used, the barcode can be read stably even after the oxidation acceleration test.

1 is a schematic configuration diagram illustrating an example of an image forming apparatus using a toner of 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)

An electrostatic charge image developing toner containing at least a binder resin and an infrared absorber,
An electrostatic charge image developing toner comprising copper-containing phenolate as an antioxidant together with the infrared absorber.   The copper-containing phenolate is bis (4-t-butyl-1,2-dithiophenolate) copper-tetra-n-butylammonium and / or bis (4-morpholinosulfenyl-1,2-dithiophenolate) 2. The electrostatic image developing toner according to claim 1, which is copper-tetra-n-butylammonium.   A toner for photofixation, wherein the toner for developing an electrostatic charge image according to claim 1 is used.   An invisible toner using the electrostatic image developing toner according to claim 1.

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