JP2011242556A - Toner for infrared laser fixing, and method of manufacturing toner for infrared laser fixing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide toner for infrared laser fixing that prevents occurrence of voids and can form an image with sufficient fixing strength, and a method of manufacturing the toner for infrared laser fixing.SOLUTION: The toner 1 for infrared laser fixing includes a binder resin 2, a coloring agent, wax 3, and an infrared absorbent 4. The infrared absorbent 4 is internally added to the wax 3. The binder resin 2 contains a crystalline polyester resin and amorphous polyester resin. The crystalline polyester resin has a melting point lower than that of the wax 3, and the amorphous polyester resin has a glass-transition temperature lower than that of the wax 3.

Description

  The present invention relates to an infrared laser fixing toner used in an image forming apparatus using an infrared laser fixing method, and a method for manufacturing the infrared laser fixing toner.

  In an image forming apparatus using an electrophotographic system, an image is formed through, for example, charging, exposure, development, transfer, cleaning, static elimination, and fixing processes. In the charging process, the surface of the photoconductor to be rotated is uniformly charged by the charging device. In the exposure process, the charged photoconductor surface is irradiated with laser light by the exposure device, and an electrostatic latent image is formed on the surface of the photoconductor. Is done. Next, in the development process, the electrostatic latent image on the surface of the photoconductor is developed with a developer by a developing device to form a toner image on the surface of the photoconductor. In the transfer step, the toner image on the surface of the photoconductor is transferred by the transfer device. Transferred to a recording medium. Thereafter, in the fixing step, the transferred toner image is fixed on the recording medium. Further, the transfer residual toner remaining on the surface of the photoconductor after the image forming operation is removed by a cleaning device in a cleaning process and collected in a predetermined recovery unit, and the residual charge on the surface of the photoconductor after cleaning is removed in a static elimination process. In order to prepare for the next image formation, the charge is removed by the charge removal device.

  As a method for fixing a toner image on a recording medium, for example, there are a hot-pressure fixing method and an infrared fixing method. In the hot-pressure fixing method, a heated roller member and a pressure member are pressed against a recording medium onto which a toner image is transferred, and the toner constituting the toner image is melted to fix the toner image on the recording medium. . In the hot-pressure fixing method, since the heated roller member comes into contact with the recording medium, there is a risk of image smearing due to hot offset, and a paper jam may occur between the roller member and the pressure member.

  On the other hand, in the infrared fixing method, the recording medium on which the toner image is transferred is irradiated with infrared rays, and the toner constituting the toner image is melted to fix the toner image on the recording medium. Therefore, in the infrared fixing method, it is not necessary to bring a heated roller member or the like into contact with the recording medium, and the occurrence of hot offset and paper jam are suppressed as compared with the hot-pressure fixing method.

  In such an infrared fixing method, as a method for improving energy efficiency, there is a method in which an infrared absorber is contained in a toner. For example, Patent Document 1 discloses a core portion including a first binder resin and a colorant. And a capsule toner having a core portion and a shell portion containing a second binder resin and an infrared absorber.

  Patent Document 2 discloses a color toner that includes a binder resin, a colorant, a charge control agent, a wax, and an infrared absorber, and the infrared absorber is held in the wax.

JP 2007-298582 A JP 2002-156775 A

  The infrared fixing method includes a flash fixing method in which the entire recording medium to which the toner image is transferred is heated with infrared rays, and an infrared laser fixing method in which only the toner images are irradiated with an infrared laser.

  When toner images composed of the toners disclosed in Patent Documents 1 and 2 are fixed by the infrared laser fixing method, the irradiation energy from the infrared laser per recording medium is small when the coverage of the formed image is small. As a result, the recording medium itself is less likely to be heated, and the heat of the toner is easily taken away by the recording medium. For this reason, the melting time of the toner is shortened and the toner is not sufficiently soaked between the fibers of the recording medium, so that a sufficient anchoring effect cannot be obtained in the toner image after fixing, and an image having sufficient fixing strength is formed. There is a problem that you can not.

  Also, in order to sufficiently infiltrate the toner between the fibers of the recording medium, if the irradiation energy of the infrared laser per unit area is increased, the toner is rapidly heated, so that the toner becomes a molten toner with extremely low viscosity, There is a problem that the molten toner aggregates due to surface tension and voids are generated, resulting in white spots in the image.

  An object of the present invention is to provide an infrared laser fixing toner capable of forming an image having sufficient fixing strength while preventing the generation of voids, and a method for manufacturing the infrared laser fixing toner.

The present invention comprises a colorant,
With wax,
An infrared absorber internally added to the wax;
An infrared laser comprising: a crystalline polyester resin having a melting point lower than the melting point of the wax; and a binder resin made of an amorphous polyester resin having a glass transition temperature lower than the melting point of the wax. It is a fixing toner.

  In the invention, it is preferable that the binder resin contains the crystalline polyester resin in a proportion of 50 wt% to 80 wt%.

  In the invention, it is preferable that the wax is contained in a ratio of 5 wt% to 10 wt% with respect to the binder resin.

In the invention, it is preferable that the wax is an ester wax.
The present invention also includes a first kneading step in which a mixture of a wax and an infrared absorber is melt-kneaded to obtain an infrared absorber-added wax;
Toner kneading by melting and kneading the infrared absorbing wax, a crystalline polyester resin having a melting point lower than that of the wax, and an amorphous polyester resin having a glass transition temperature lower than that of the wax. A second kneading step for obtaining a product,
And a pulverizing process for pulverizing the toner kneaded product.

  According to the present invention, the infrared laser fixing toner includes a binder resin, a colorant, a wax, and an infrared absorber. The infrared absorber is internally added in the wax. The binder resin includes a crystalline polyester resin and an amorphous polyester resin. The crystalline polyester resin has a melting point lower than that of the wax, and the amorphous polyester resin has a glass transition temperature higher than that of the wax. Is also low.

  In such an infrared laser fixing toner, the infrared absorbent that has absorbed the irradiation energy of the infrared laser generates heat. The heat generated from this infrared absorber is used as melting energy for melting the wax and stored in the wax, so that the temperature rise of the infrared laser fixing toner is suppressed until the wax melts, and the infrared laser fixing It is possible to suppress a rapid increase in the toner temperature. Since the infrared absorber is internally added to such a wax, the heat generated in the infrared absorber is transferred to the binder resin through the wax, so that the temperature of the binder resin rapidly increases. It can suppress and generation | occurrence | production of a void can be suppressed.

  In addition, the temperature of the infrared laser fixing toner decreases after the infrared laser irradiation, but until the wax is solidified from the melted state, the infrared laser is heated by the melting energy (crystallization energy) stored in the wax. The temperature of the fixing toner is maintained near the melting point of the wax. In the infrared laser fixing toner of the present invention, the melting point of the crystalline polyester resin is lower than the melting point of the wax, and the glass transition temperature of the amorphous polyester resin is lower than the melting point of the wax, so that the wax solidifies from the molten state. In the meantime, the crystalline polyester resin and the amorphous polyester resin are maintained in a molten state, whereby the infrared laser fixing toner is maintained in a molten state. Therefore, the infrared laser fixing toner can penetrate between the fibers of the recording medium even when the irradiation energy of the infrared laser at the time of fixing is small, so that the anchor effect is improved and an image having sufficient fixing strength is formed. be able to.

  According to the invention, the binder resin contains a crystalline polyester resin in a proportion of 50 wt% to 80 wt%. When the binder resin contains the crystalline polyester resin in a proportion of 50 wt% or more and 80 wt% or less, the melted toner for infrared laser fixing has an appropriate viscosity at the time of fixing. As a result, the infrared laser fixing toner can suppress the generation of voids, improve the anchor effect, and stably form an image having a sufficient fixing strength.

  According to the invention, the wax is contained in a proportion of 5% by weight to 10% by weight with respect to the binder resin. By containing the wax in a proportion of 5% by weight or more and 10% by weight or less with respect to the binder resin, a sufficient heat storage effect can be exhibited, so that generation of voids can be suppressed and an infrared laser at the time of fixing. Even when the irradiation energy by is small, an image having a sufficient fixing strength can be formed.

  According to the invention, the wax is an ester wax. The ester wax is uniformly dispersed without agglomeration in the binder resin. Therefore, the infrared absorber internally added to the wax is also uniformly dispersed in the binder resin. Accordingly, the heat generated from the infrared absorbent by the irradiation of the infrared laser is uniformly transmitted to the entire infrared laser fixing toner, so that generation of voids can be suppressed.

  According to the invention, the method for producing the infrared laser fixing toner for infrared laser fixing includes a first kneading step, a second kneading step, and a pulverizing step. In the first kneading step, a mixture containing a wax and an infrared absorber is melt-kneaded to obtain an infrared absorber-containing wax. In the second kneading step, the infrared absorbing agent-containing wax, a crystalline polyester resin having a melting point lower than the melting point of the wax, and an amorphous polyester resin having a glass transition temperature lower than the melting point of the wax are melt-kneaded. Thus, a toner kneaded product is obtained. In the pulverization step, the toner kneaded product is pulverized.

  Thus, an infrared laser fixing toner in which the infrared absorbing agent-added wax is dispersed can be obtained. Such an infrared laser fixing toner can suppress the generation of voids and can form an image having a sufficient fixing strength even when the irradiation energy of the infrared laser during fixing is small.

1 is a cross-sectional view schematically showing a configuration of an infrared laser fixing toner 1 according to a first embodiment of the present invention. FIG. 5 is a process diagram illustrating a method for manufacturing the infrared laser fixing toner 1. 1 is a schematic diagram schematically showing a configuration of an image forming apparatus 100. FIG. 2 is a schematic diagram schematically showing a configuration of a developing device 24. FIG. 2 is a schematic diagram schematically illustrating a configuration of a fixing unit 40. FIG.

1. Infrared Laser Fixing Toner FIG. 1 is a cross-sectional view schematically showing a configuration of an infrared laser fixing toner 1 according to a first embodiment of the present invention. An infrared laser fixing toner (hereinafter simply referred to as “toner”) 1 of the present embodiment includes a binder resin 2, a colorant, and an infrared absorbing wax 5. The infrared absorbent internal wax 5 is configured by internally adding an infrared absorbent 4 to the wax 3.

(Binder resin)
The binder resin 2 includes a crystalline polyester resin and an amorphous polyester resin.

  As a crystalline polyester resin and an amorphous polyester resin, a well-known thing can be used, For example, the polycondensate of a polybasic acid and a polyhydric alcohol etc. can be mentioned. Polybasic acids are polybasic acids and derivatives of polybasic acids, such as acid anhydrides or esterified products of polybasic acids, and polyhydric alcohols are compounds containing two or more hydroxyl groups. Yes, including both alcohols and phenols.

  As the polybasic acid, those known as polyester resin monomers can be used. For example, aromatic carboxylic acids such as terephthalic acid, isophthalic acid, phthalic anhydride, trimellitic anhydride, pyromellitic acid, naphthalenedicarboxylic acid, etc. And aliphatic carboxylic acids such as maleic anhydride, fumaric acid, succinic acid, alkenyl succinic anhydride, and adipic acid, and methyl esterified products of these polybasic acids. A polybasic acid can be used individually by 1 type, and may use 2 or more types together.

  As the polyhydric alcohol, those known as polyester resin monomers can be used, for example, aliphatic polyhydric alcohols such as ethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, glycerin, Aromatic diols such as cycloaliphatic polyhydric alcohols such as cyclohexanediol, cyclohexanedimethanol and hydrogenated bisphenol A, ethylene oxide adducts of bisphenol A, propylene oxide adducts of bisphenol A, and the like can be mentioned. A polyhydric alcohol can be used individually by 1 type, and may use 2 or more types together.

  The polyester resin can be synthesized by a condensation polymerization reaction. For example, it can be synthesized by polycondensation reaction, specifically dehydration condensation reaction of polybasic acids and polyhydric alcohols in the presence of a catalyst in an organic solvent or without solvent. At this time, a methyl esterified product of a polybasic acid may be used as a part of the polybasic acid to perform a demethanol polycondensation reaction. The polycondensation reaction may be terminated when the acid value and softening temperature of the polyester resin produced by the reaction reach values in the target polyester resin. In this polycondensation reaction, by appropriately changing the reaction conditions such as the blending ratio of polybasic acids and polyhydric alcohols and the reaction rate, for example, the content of the carboxyl group bonded to the terminal of the polyester resin to be synthesized, Furthermore, other physical property values such as glass transition temperature can be adjusted by adjusting the acid value of the polyester resin.

  If a methyl esterified product of a polybasic acid is used as part of the polybasic acid, a demethanol polycondensation reaction occurs. In this polycondensation reaction, for example, the carboxyl group content at the terminal of the polyester can be adjusted by appropriately changing the blending ratio of polybasic acid and polyhydric alcohol, the reaction rate, etc. As a result, the modified polyester Can be obtained. A modified polyester can also be obtained by using trimellitic anhydride as a polybasic acid and introducing a carboxyl group into the main chain of the polyester. Alternatively, a self-dispersible polyester having self-dispersibility in water can be obtained by bonding a hydrophilic group such as a carboxyl group or a sulfonic acid group to at least one of the main chain or side chain of the polyester. it can. Further, a polyester resin and an acrylic resin may be grafted.

  In the present embodiment, “crystalline” means that the ratio of the softening temperature to the maximum peak temperature of the heat of fusion (softening temperature / maximum peak temperature of the heat of fusion) is 0.9 or more and 1.1 or less in the resin. Yes, preferably means 0.98 or more and 1.05 or less. The term “amorphous” means that the ratio between the softening temperature and the maximum peak temperature of the heat of fusion is 1.1 or more and 4.0 or less, preferably 1.5 or more and 3.0 or less. .

  The melting point of the crystalline polyester resin is a temperature range of 50 ° C. or higher and lower than the melting point of the wax 3.

  The glass transition temperature of the amorphous polyester resin is in the temperature range of 50 ° C. or higher and lower than the melting point of the wax 3.

  The content of the crystalline polyester resin is preferably 50% by weight or more and 80% by weight or less with respect to the total amount of the binder resin 2. When the content of the crystalline polyester resin is 50% by weight or more and 80% by weight or less with respect to the total amount of the binder resin 2, the melted toner 1 has an appropriate viscosity at the time of fixing. As a result, the toner 1 can suppress the generation of voids, improve the anchor effect, and stably form an image having a sufficient fixing strength. When the content of the crystalline polyester resin is less than 50% by weight, the viscosity of the toner 1 is not sufficiently lowered when the irradiation energy by the infrared laser at the time of fixing is small, and the toner 1 penetrates between the fibers of the recording medium. This makes it difficult to form an image having a sufficient fixing strength. When the content of the crystalline polyester resin exceeds 80% by weight, the viscosity of the toner 1 is excessively lowered at the time of fixing, and voids are easily generated.

  The ratio of the content of the crystalline polyester resin and the content of the amorphous polyester resin is preferably 50:50 to 80:20.

  The crystalline polyester resin and the amorphous polyester resin are preferably contained in a proportion of 80 wt% or more and 100 wt% or less with respect to the total amount of the binder resin 2. When the crystalline polyester resin and the amorphous polyester resin are contained in a proportion of 80% by weight or more and 100% by weight or less with respect to the total amount of the binder resin 2, transparency is high and mechanical strength is remarkably impaired. Therefore, it is possible to obtain the toner 1 having a characteristic of melting at a low temperature.

  The binder resin 2 may include a resin other than the crystalline polyester resin and the amorphous polyester resin. As resins other than the crystalline polyester resin and the amorphous polyester resin, polystyrene, poly-α-methylstyrene, chloropolystyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene copolymer, Styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer, styrene-maleic acid copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-acrylic acid ester-methacrylic acid Styrenic resins such as ester copolymers, styrene-α-chloroacrylic acid methyl copolymers, styrene-acrylonitrile-acrylic acid ester copolymers, amorphous polyester resins, epoxy resins, urethane modified epoxy resins, silicone modified epoxies Resin, chloride Vinyl resin, rosin modified maleic acid resin, phenyl resin, polyethylene, polypropylene, ionomer resin, polyurethane resin, silicone resin, ketone resin, ethylene-ethyl acrylate copolymer, xylene resin, polyvinyl butyral resin, terpene resin, phenol resin, fat And binder resins for toner such as aromatic or alicyclic hydrocarbon resins.

  The glass transition temperature (Tg) of the binder resin 2 is not particularly limited and can be appropriately selected from a wide range. However, considering the fixability and storage stability of the obtained toner 1, the glass transition temperature (Tg) is 30 ° C. or higher and 80 ° C. or lower. Preferably there is. When the temperature is less than 30 ° C., the storage stability becomes insufficient, so that the toner 1 is likely to be thermally aggregated inside the image forming apparatus, and development failure may occur.

  Further, the temperature at which the high temperature offset phenomenon starts to occur (hereinafter referred to as “high temperature offset start temperature”) decreases. The “high temperature offset phenomenon” means that when toner 1 is fixed on a recording medium by heating and pressurizing with a fixing member such as a heating roller, the cohesive force between toner particles is caused by the overheating of toner 1 and the adhesive force between toner 1 and the fixing member. This is a phenomenon in which a part of the toner 1 adheres to and is removed from the fixing member because the toner layer is divided below. On the other hand, if the glass transition temperature exceeds 80 ° C., the fixing property is deteriorated, so that fixing failure may occur.

  The molecular weight of the binder resin 2 is not particularly limited and can be appropriately selected from a wide range, but the weight average molecular weight (Mw) is preferably 5,000 or more and 500,000 or less. Here, the weight average molecular weight of the binder resin 2 is a value converted on the basis of polystyrene simultaneously analyzed by gel permeation chromatography (abbreviation GPC).

  When the molecular weight is less than 5,000, the mechanical strength of the binder resin 2 is reduced, and the resulting toner particles are easily pulverized by stirring in the developing device, so that the shape of the toner particles changes. There is a risk of variation in charging performance. Further, when the molecular weight exceeds 500,000, it becomes difficult to melt, so that kneading in the kneading step becomes difficult, and the dispersibility of the colorant, wax 3 and charge control agent in the kneaded product is impaired, and the toner 1 is fixed. May deteriorate and fixing failure may occur.

(Coloring agent)
As the colorant, organic dyes, organic pigments, inorganic dyes, inorganic pigments and the like commonly used in the electrophotographic field can be used.

  Examples of the black colorant include carbon black, copper oxide, manganese dioxide, aniline black, activated carbon, nonmagnetic ferrite, magnetic ferrite, and magnetite.

  Examples of yellow colorants include chrome lead, zinc yellow, cadmium yellow, yellow iron oxide, mineral fast yellow, nickel titanium yellow, navel yellow, naphthol yellow S, Hansa yellow G, Hansa yellow 10G, benzidine yellow G, and benzidine. Yellow GR, Quinoline Yellow Lake, Permanent Yellow NCG, Tartrazine Lake, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 180, C.I. I. And CI Pigment Yellow 185.

  Examples of the magenta colorant include the color index name C.I. I. Pigment red 49, C.I. I. Pigment red 57, C.I. I. Pigment red 81, C.I. I. Pigment red 122, C.I. I. Solvent Red 19, C.I. I. Solvent Red 49, C.I. I. Solvent Red 52, C.I. I. Basic Red 10 and C.I. I. Disperse Red 15 etc. can be mentioned.

  Examples of cyan colorants include color index names C.I. I. Pigment blue 15, C.I. I. Pigment blue 16, C.I. I. Solvent Blue 55, C.I. I. Solvent Blue 70, C.I. I. Direct Blue 25, and C.I. I. Direct Blue 86 and the like can be mentioned.

  Examples of the black colorant include carbon black such as channel black, roller black, disk black, gas furnace black, oil furnace black, thermal black, and acetylene black.

  Examples of the orange colorant include red chrome yellow, molybdenum orange, permanent orange GTR, pyrazolone orange, vulcan orange, indanthrene brilliant orange RK, benzidine orange G, indanthrene brilliant orange GK, C.I. I. Pigment orange 31, C.I. I. And CI Pigment Orange 43.

  Examples of red colorants include bengara, cadmium red, red lead, mercury sulfide, cadmium, permanent red 4R, risor red, pyrazolone red, watching red, calcium salt, lake red C, lake red D, and brilliant carmine 6B. Eosin Lake, Rhodamine Lake B, Alizarin Lake, Brilliant Carmine 3B, C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 166, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. And CI Pigment Red 222.

  Examples of purple colorants include manganese purple, fast violet B, and methyl violet lake.

  Examples of blue colorants include bitumen, cobalt blue, alkali blue lake, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, phthalocyanine blue partially chlorinated products, first sky blue, induslen blue BC, C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 16, C.I. I. And CI Pigment Blue 60.

  Examples of the green colorant include chrome green, chromium oxide, pigment green B, micalite green lake, final yellow green G, C.I. I. And CI Pigment Green 7.

  Examples of the white colorant include compounds such as zinc white, titanium oxide, antimony white, and zinc sulfide. The colorant can be used alone or in combination of two or more different colors. Further, two or more of the same color may be used in combination.

  The content of the colorant is not particularly limited, but is preferably 4 parts by weight or more and 20 parts by weight or less with respect to 100 parts by weight of the binder resin 2. Thereby, it is possible to obtain a toner 1 having a high coloring power while suppressing an undesirable filler effect due to the addition of the colorant. When the blending amount of the colorant exceeds 20 parts by weight, the fixability of the toner 1 may be lowered due to the filler effect of the colorant. Further, if it is less than 4 parts by weight, sufficient coloring cannot be obtained.

  In order to uniformly disperse the colorant in the binder resin 2, the colorant may be used as a master batch. A master batch of a colorant can be produced, for example, by kneading a resin melt and a colorant. As the resin, the same type of resin as the binder resin 2 or a resin having good compatibility with the binder resin 2 is used. The use ratio of the resin and the colorant in the master batch is not particularly limited, but is preferably 30 parts by weight or more and 100 parts by weight or less with respect to 100 parts by weight of the synthetic resin. For example, the master batch is used after being granulated to have a particle diameter of 2 mm or more and 3 mm or less.

  Two or more colorants may be used in the form of composite particles. The composite particles can be produced, for example, by adding an appropriate amount of water, a polar solvent, or the like to two or more colorants, granulating with a general granulator such as a high speed mill, and drying. The master batch and the composite particles are mixed into the toner raw material in the second kneading step described later.

(wax)
Examples of the wax 3 include petroleum wax such as ester wax, carnauba wax and derivatives thereof, paraffin wax and derivatives thereof, microcrystalline wax and derivatives thereof, Fischer-Tropsch wax and derivatives thereof, and polyolefin wax (polyethylene wax, polypropylene wax). Etc.) and derivatives thereof, low molecular weight polypropylin wax and derivatives thereof, hydrocarbon synthetic waxes such as polyolefin polymer wax (low molecular weight polyethylene wax etc.) and derivatives thereof, rice wax and derivatives thereof, candelilla wax and derivatives thereof , Plant waxes such as wood wax, animal waxes such as beeswax and spermaceti, fat and oil synthetic waxes such as fatty acid amides and phenol fatty acid esters, long Carboxylic acid and its derivatives, long chain alcohols and derivatives thereof, silicone polymers, such as higher fatty acids.

  Of these waxes 3, it is preferable to use ester waxes. Since the ester wax is uniformly dispersed without agglomeration in the binder resin 2, the infrared absorber 4 internally added to the wax 3 is also uniformly distributed in the binder resin 2 by using the ester wax. Will be distributed. Therefore, the heat generated from the infrared absorbent 4 by the irradiation of the infrared laser is uniformly transmitted to the entire toner 1, so that generation of voids can be suppressed.

  The wax 3 is added for the purpose of imparting a heat storage effect to the toner 1. By including the wax 3 in the toner 1, the heat generated from the infrared absorbent 4 that has absorbed the irradiation energy of the infrared laser is used as melting energy for melting the wax 3 and is stored in the wax 3. Until the wax 3 is melted, the temperature rise of the toner 1 is suppressed, and the temperature of the toner 1 can be prevented from rising rapidly.

  In addition, the temperature of the toner 1 decreases after irradiation of the infrared laser, but until the wax 3 is solidified from the melted state, the melting energy (crystallization energy) stored in the wax 3 causes the toner 1 to accumulate. The temperature is maintained near the melting point of the wax 3. During this time, the crystalline polyester resin having a melting point lower than that of the wax 3 and the amorphous polyester resin having a glass transition temperature lower than the melting point of the wax 3 are maintained in a molten state, whereby the toner 1 is in a molten state. To maintain. Therefore, the toner 1 can sufficiently permeate between the fibers of the recording medium even when the irradiation energy from the infrared laser at the time of fixing is small, so that the anchor effect is improved and an image having sufficient fixing strength is formed. be able to.

  The melting point of the wax 3 is preferably 120 ° C. or lower, exceeding the melting point of the crystalline polyester resin and the glass transition temperature of the amorphous polyester resin. When the melting point of the wax 3 exceeds 120 ° C., when the irradiation energy by the infrared laser is small, the toner 1 cannot sufficiently exhibit the heat storage effect, and the fixability may be lowered.

  The latent heat amount of the wax 3 is preferably 100 J / g or more and 300 J / g or less. When the amount of latent heat is less than 100 J / g, it is difficult to obtain an image having a low heat storage effect and sufficient fixing strength. The wax 3 having a latent heat amount exceeding 300 J / g is difficult to uniformly disperse in the binder resin 2.

  The content of the wax 3 is preferably 5% by weight or more and 10% by weight or less with respect to the total amount of the binder resin 2. Since the content of the wax 3 is 5% by weight or more and 10% by weight or less with respect to the total amount of the binder resin 2, a sufficient heat storage effect can be exhibited, so that generation of voids can be suppressed and fixing can be performed. Even when the irradiation energy of the infrared laser is small, an image having a sufficient fixing strength can be formed. If the content of the wax 3 is less than 5% by weight, a sufficient heat storage effect cannot be exhibited, and if the irradiation energy by the infrared laser at the time of fixing is low, an image having a sufficient fixing strength may not be formed. . In addition, there is a risk of voids. If the content of the wax 3 exceeds 10% by weight, filming on the photoconductor and spent on the carrier may easily occur. Further, the wax 3 is likely to enter between the binder resin 2 and the recording medium, and the fixing strength may be reduced.

(Infrared absorber)
As the infrared absorbent 4, a known one can be used, and any infrared absorbent that has absorption in the infrared region can be used without particular limitation. For example, the infrared absorber 4 which consists of 1 type, or 2 or more types of compounds chosen from a cyanine compound, carbon black, a diimonium compound, an aminium compound, a polymethine compound, a phthalocyanine compound, etc. is mentioned.

  Examples of the cyanine compound include KAYASORB CY-40MC and CYP-4646 (F) (trade name) manufactured by Nippon Kayaku Co., Ltd., NK-4680 (trade name) of Hayashibara Biochemical Laboratories, Ltd., Sumitomo Seika Co., Ltd. SD50-E05N (trade name) manufactured by Co., Ltd. can be exemplified.

  Examples of the diimonium compound include CIR-1085 and CIR-1085F (all are trade names) manufactured by Nippon Carlit Co., Ltd.

  Examples of the aminium compound include NIR-AM1 (trade name) manufactured by Nagase ChemteX Corporation.

  Examples of the polymethine compound include IRT (trade name) manufactured by Showa Denko KK.

  Examples of the phthalocyanine compound include IR-10A and IR-12 (trade name) manufactured by Nippon Shokubai Co., Ltd.

Among these compounds, the cyanine compound has a maximum absorption peak and a high extinction coefficient (10 ^{× 5} or more) in a wavelength range of 780 nm or more and 1000 nm or less, and thus has high laser light absorption efficiency and is preferable as the infrared absorber 4. Further, by including a cyanine compound as the infrared absorbing agent 4, it is possible to obtain a higher effect of ensuring sufficient fixability in the laser fixing system and preventing whiteout of the image due to voids.

The infrared absorbent 4 preferably has an absorption maximum wavelength λmax in a wavelength range of 780 nm or more and 1000 nm or less. The absorption of visible light by the infrared absorbent 4 is preferably as small as possible in order to suppress the influence on the hue of the toner 1. Here, “infrared rays” refers to electromagnetic waves having a wavelength of 780 nm to 10 ⁶ nm (1 mm), and “visible rays” refers to electromagnetic waves having a wavelength of 380 nm to less than 780 nm.

  In the toner 1, the infrared absorber 4 is internally added in the wax 3. Since the infrared absorbent 4 is internally added to the wax 3, heat generated in the infrared absorbent 4 is transmitted to the binder resin 2 through the wax 3, so that generation of voids can be suppressed. . If the infrared absorbent 4 is not internally added to the wax 3 and the infrared absorbent 4 and the binder resin 2 are in contact with each other, the temperature of the binder resin 2 in contact with the infrared absorbent 4 during fixing is abrupt. Therefore, voids are generated, and white spots are likely to occur in the formed image.

  The content of the infrared absorber 4 is preferably 0.01 wt% or more and 1 wt% or less with respect to the binder resin 2. When the content of the infrared absorber 4 is 0.01% by weight or more and 1% by weight or less with respect to the binder resin 2, the toner 1 is sufficiently fixed, and the white spots of the image and the saturation are reduced. Can be suppressed.

  When the content of the infrared absorbent 4 is less than 0.01% by weight, the amount of heat generated by the infrared absorbent 4 due to the infrared laser irradiation decreases, and the toner 1 is not sufficiently melted, and the fixability may be lowered. . When the content of the infrared absorbent 4 exceeds 1% by weight, the temperature of the toner 1 is rapidly increased by irradiation with the infrared laser, and voids may be generated to cause white spots in the image. Furthermore, since the amount of visible light absorbed by the infrared absorber 4 increases, the saturation of the image may be reduced.

(Charge control agent)
The toner 1 may contain a charge control agent in addition to the binder resin 2, the colorant, the wax 3 and the infrared absorber 4.

  The charge control agent is added as necessary for the purpose of imparting preferable chargeability to the toner 1. The charge control agent is not particularly limited, and charge control agents for positive charge control and negative charge control commonly used in this field can be used.

  Examples of the charge control agent for positive charge control include nigrosine dyes, basic dyes, quaternary ammonium salts, quaternary phosphonium salts, aminopyrines, pyrimidine compounds, polynuclear polyamino compounds, aminosilanes, nigrosine dyes and derivatives thereof, and triphenylmethane. Derivatives, guanidine salts, amidine salts and the like can be mentioned.

  Charge control agents for controlling negative charge include oil-soluble dyes such as oil black and spiron black, metal-containing azo compounds, azo complex dyes, naphthenic acid metal salts, metal complexes and metal salts of salicylic acid and its derivatives (metal is Chromium, zinc, zirconium, etc.), boron compounds, fatty acid soaps, long-chain alkyl carboxylates, resin acid soaps, and the like.

  One charge control agent can be used alone, or two or more charge control agents may be used in combination as required.

  The content of the charge control agent is not particularly limited and can be appropriately selected from a wide range, but is preferably 0.5 parts by weight or more and 5 parts by weight or less with respect to 100 parts by weight of the binder resin 2. More preferably, it is 0.5 part by weight or more and 3 parts by weight or less with respect to 100 parts by weight of the binder resin 2. When the charge control agent exceeds 5 parts by weight, the carrier is contaminated and toner scattering occurs. Further, when the content of the charge control agent is less than 0.5 parts by weight, the toner 1 cannot be provided with sufficient chargeability.

2. Manufacturing method of toner The manufacturing method of the above-mentioned toner 1 is described below. FIG. 2 is a process diagram showing a method of manufacturing the infrared laser fixing toner 1. The manufacturing method of the toner 1 shown in FIG. 2 includes a first kneading step S1, a second kneading step S2, and a pulverizing step S3.

(First kneading step)
In the first kneading step of step S1, the infrared absorbent internal additive wax 5 in which the infrared absorbent 4 is dispersed in the wax 3 is obtained.

  The infrared absorbing agent-added wax 5 is obtained by mixing the wax 3 and the infrared absorbing agent 4 using a mixer to obtain a mixture, then melt-kneading the mixture using a kneader, and cooling and solidifying the melt-kneaded product. And then pulverized with a crusher.

  As the mixer, for example, a Henschel type mixing device such as Henschel mixer (trade name, manufactured by Mitsui Mining Co., Ltd.), Super Mixer (trade name, manufactured by Kawata Co., Ltd.), Mechano Mill (trade name, manufactured by Okada Seiko Co., Ltd.), etc. , Ongmill (trade name, manufactured by Hosokawa Micron Corporation), hybridization system (trade name, manufactured by Nara Machinery Co., Ltd.), Cosmo system (trade name, manufactured by Kawasaki Heavy Industries, Ltd.), and the like.

  Examples of the kneader include general kneading such as a twin-screw extruder, a three-roller, and a lab blast mill. More specifically, for example, TEM-100B (trade name, manufactured by Toshiba Machine Co., Ltd.), PCM-65 / 87, PCM-30 (all are trade names, manufactured by Ikegai Co., Ltd.), etc. Open roll type kneaders such as Extruder or Needex (trade name, manufactured by Mitsui Mining Co., Ltd.). Among these, an open roll kneader is particularly preferable.

An example of the coarse powder machine is a feather mill.
The temperature at the time of kneading in the first kneading step S1 is preferably not lower than the melting point of the wax 3 and not higher than 180 ° C.

(Second kneading step)
In the second kneading step in step S2, a toner kneaded product in which the colorant, the infrared absorbing wax 5 and the like are dispersed in the binder resin 2 is obtained.

The toner kneaded product is obtained by melt-kneading toner raw materials such as the binder resin 2, the colorant, the infrared absorbing agent-added wax 5 and the charge control agent using a kneader.
As the kneader, the kneader used in the first kneading step S1 can be used.

  By melt-kneading in the second kneading step S2, the infrared absorbent internal wax 5 having a particle size of about 1 mm at the time of manufacture in the first kneading step S1 has a small particle size. Specifically, the volume average particle of the infrared absorbing agent added wax 5 after being melt-kneaded in the second kneading step S2 is preferably 0.1 μm or more and 0.3 μm or less. That is, the dispersion diameter of the infrared absorbing agent added wax 5 in the toner kneaded product (toner 1) is preferably 0.1 μm or more and 0.3 μm or less. In the toner kneaded product (toner 1), the infrared absorbent 4 is in a state of being internally added to the wax 3.

(Crushing process)
In the pulverization step of step S3, the toner kneaded product is pulverized by a pulverizer and classified by a classifier as necessary to obtain toner 1.

  As the pulverizer, for example, a jet mill that pulverizes using a supersonic jet stream can be used.

  As the classifier, a known classifier that removes excessively pulverized toner mother particles by centrifugal force and wind classification can be used. For example, a swirl type wind classifier (rotary wind classifier) is used. it can.

  The volume average particle size of the toner 1 obtained as described above is preferably 5.0 μm or more and 8.0 μm or less.

  The toner 1 may be mixed with an external additive having functions such as powder flowability improvement, triboelectric chargeability improvement, heat resistance, long-term storage stability improvement, cleaning property improvement and photoreceptor surface wear property control.

  As the external additive, those commonly used in this field can be used, and examples thereof include silica fine powder, titanium oxide fine powder, and alumina fine powder. These inorganic fine powders are for the purpose of hydrophobization, chargeability control, etc., silicone varnish, various modified silicone varnishes, silicone oil, various modified silicone oils, silane coupling agents, silane coupling agents having functional groups, and other It is preferably treated with an organosilicon compound or the like, and one kind can be used alone, or two or more kinds can be used in combination.

  In consideration of the charge amount necessary for the toner 1, the influence on the abrasion of the photoreceptor due to the addition of the external additive and the environmental characteristics of the toner 1, the additive amount of the external additive is 100 parts by weight of the toner 1. 1 to 10 parts by weight is preferable, and 1 to 5 parts by weight is more preferable.

  The volume average particle size of primary particles of the external additive is preferably 10 nm or more and 500 nm or less. By using an external additive having such a particle size, the fluidity of the toner 1 can be further improved.

  The toner 1 can be used as it is as a one-component developer without adding a carrier, or can be mixed with a carrier and used as a two-component developer.

  When used as a one-component developer, toner 1 that has been frictionally charged with a developing sleeve using a blade and a fur brush is adhered onto the sleeve, whereby toner 1 is conveyed and image formation is performed. When used as a two-component developer, toner 1 is used with a carrier.

  Since the one-component developer and the two-component developer include the toner 1 capable of maintaining stable charging performance in a high humidity environment, the one-component developer and the two-component developer become a two-component developer having high charging stability even in a high humidity environment.

  As the carrier, known ones can be used, for example, resin coating in which iron, copper, zinc, nickel, cobalt, manganese, chromium, etc. alone or composite ferrite and carrier core particles are coated with a coating material. Examples thereof include a carrier or a resin-dispersed carrier in which magnetic particles are dispersed in a resin.

  As the coating material, known materials can be used. For example, polytetrafluoroethylene, monochlorotrifluoroethylene polymer, polyvinylidene fluoride, silicone resin, polyester resin, metal compound of ditertiary butyl salicylic acid, styrene resin Acrylic resin, polyacid, polyvinyllar, nigrosine, aminoacrylate resin, basic dye, basic dye lake, silica fine powder, alumina fine powder, and the like.

  The resin used for the resin-dispersed carrier is not particularly limited, and examples thereof include styrene acrylic resin, polyester resin, fluorine-based resin, and phenol resin. Both are preferably selected according to the components of the toner 1, and one kind can be used alone, or two or more kinds may be used in combination.

  The shape of the carrier is preferably a spherical shape or a flat shape. The particle diameter is not particularly limited, but considering high image quality, it is preferably 10 μm or more and 100 μm or less, more preferably 20 μm or more and 50 μm or less.

The resistivity of the carrier is preferably 10 ⁸ Ω · cm or more, more preferably 10 ¹² Ω · cm or more. Resistivity after tapping put carrier particles in a container of the cross-sectional area 0.50 cm ^2, applying a load of particles 1 kg / cm ² in the container, an electric field of 1000V / cm between the load and a bottom electrode It is a value obtained from the current value when the resulting voltage is applied. If the resistivity is low, the carrier particles are charged when a bias voltage is applied to the developing sleeve, and the carrier particles easily adhere to the photoreceptor.

  The magnetization strength (maximum magnetization) of the carrier is preferably 10 emu / g or more and 60 emu / g or less, more preferably 15 emu / g or more and 40 emu / g or less. Under the general magnetic flux density condition of the developing roller 72, if the magnetization strength is less than 10 emu / g, the magnetic binding force does not work, which may cause carrier scattering. If it exceeds 60 emu / g, the non-contact development will cause the carrier to grow too high, making it difficult to maintain the non-contact state between the image carrier and the toner 1. Further, in the contact development, there is a possibility that a sweep is likely to appear in the toner image.

The mixing ratio of the toner 1 and the carrier in the two-component developer is not particularly limited, and can be appropriately selected according to the type of the toner 1 and the carrier. For example, when mixed with a resin-coated carrier (density 5 g or more and 8 g or less / cm ² ), toner 1 is preferably 2% by weight or more and 30% by weight or less of the total developer amount, more preferably 2% by weight or more. 20% by weight or less may be included. Further, the coverage of the carrier with the toner 1 is preferably 40% or more and 80% or less.

3. Image Forming Apparatus The toner 1 of the present invention can be used in an infrared laser fixing type image forming apparatus 100 shown in FIG. FIG. 3 is a schematic diagram schematically showing the configuration of the image forming apparatus 100. The image forming apparatus 100 is a multifunction device having both a copying function, a printer function, and a facsimile function, and forms a full-color or monochrome image on a recording medium according to transmitted image information. The image forming apparatus 100 has three types of printing modes, ie, a copier mode (copy mode), a printer mode, and a facsimile mode, and an operation input from an operation unit (not shown), a personal computer, a portable terminal device, an information recording storage A print mode is selected by a control unit (not shown) in response to reception of a print job from an external device using a medium or a memory device.

  The image forming apparatus 100 includes a toner image forming unit 20, a transfer unit 30, a fixing unit 40, a recording medium supply unit 50, a discharge unit 60, and a control unit unit (not shown). The toner image forming unit 20 includes photosensitive drums 21b, 21c, 21m, and 21y, charging units 22b, 22c, 22m, and 22y, an exposure unit 23, developing devices 24b, 24c, 24m, and 24y, a cleaning unit 25b, 25c, 25m, 25y. The transfer unit 30 includes an intermediate transfer belt 31, a driving roller 32, a driven roller 33, intermediate transfer rollers 34 b, 34 c, 34 m and 34 y, a transfer belt cleaning unit 35, and a transfer roller 36.

  The photosensitive drum 21, the charging unit 22, the developing device 24, the cleaning unit 25, and the intermediate transfer roller 34 are black (b), cyan (c), magenta (m), and yellow (y) included in the color image information. In order to correspond to the image information of each color, four each are provided. In this specification, when distinguishing each member provided by four according to each color, an alphabet representing each color is added to the end of a number representing each member as a reference symbol, and when each member is collectively referred to Only numerals representing each member are used as reference numerals.

  The photosensitive drum 21 is supported by a drive unit (not shown) so as to be rotatable around an axis, and includes a conductive substrate (not shown) and a photosensitive layer formed on the surface of the conductive substrate. The conductive substrate can take various shapes, and examples thereof include a cylindrical shape, a columnar shape, and a thin film sheet shape. The photosensitive layer is formed, for example, by laminating a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material.

  The charging unit 22, the developing device 24, and the cleaning unit 25 are arranged in this order around the rotation direction of the photosensitive drum 21. The charging unit 22 is disposed below the developing device 24 and the cleaning unit 25 in the vertical direction.

  The charging unit 22 is a member that charges the surface of the photosensitive drum 21 to a predetermined polarity and potential. The charging unit 22 is installed along the longitudinal direction of the photosensitive drum 21 at a position facing the photosensitive drum 21. In the case of a contact charging type charging device, the charging unit 22 is installed in contact with the surface of the photosensitive drum 21. In the case of a non-contact charging type charging device, the charging unit 22 is installed so as to be separated from the surface of the photosensitive drum 21.

  The charging unit 22 is installed around the photosensitive drum 21 together with the developing device 24, the cleaning unit 25, and the like. The charging unit 22 is preferably installed at a position closer to the photosensitive drum 21 than the developing device 24, the cleaning unit 25, and the like. As a result, it is possible to reliably prevent the charging failure of the photosensitive drum 21.

  As the charging unit 22, a brush-type charging device, a roller-type charging device, a corona discharge device, an ion generation device, or the like can be used. The brush type charging device and the roller type charging device are contact charging type charging devices. As the brush type charging device, there are a type using a charging brush and a type using a magnetic brush. The corona discharge device and the ion generator are non-contact charging devices. Corona discharge devices include those using wire-like discharge electrodes, those using sawtooth discharge electrodes, and those using needle-like discharge electrodes.

  The exposure unit 23 is arranged so that light emitted from the exposure unit 23 passes between the charging unit 22 and the developing device 24 and is irradiated on the surface of the photosensitive drum 21. The exposure unit 23 irradiates the charged surface of the photosensitive drums 21b, 21c, 21m, and 21y with laser beams corresponding to the image information of the respective colors, so that each of the photosensitive drums 21b, 21c, 21m, and 21y is exposed. An electrostatic latent image corresponding to the image information of each color is formed on the surface. As the exposure unit 23, for example, a laser scanning unit (LSU) including a laser irradiation unit and a plurality of reflection mirrors can be used. As the exposure unit 23, an LED (Light Emitting Diode) array, a unit in which a liquid crystal shutter and a light source are appropriately combined, or the like may be used.

  FIG. 4 is a schematic diagram schematically showing the configuration of the developing device 24. The developing device 24 includes a developing tank 241 and a toner hopper 242. The developing tank 241 contains the developer according to the present invention in its internal space. In the developing tank 241, roller-like or screw-like members such as a developing roller 243, a supply roller 244, and a stirring roller 245 are rotatably supported. An opening is formed in a side surface of the developing tank 241 facing the photosensitive drum 21, and a developing roller 243 is provided at a position facing the photosensitive drum 21 through the opening.

  The developing roller 243 is a member that supplies the toner 1 to the electrostatic latent image on the surface of the photosensitive drum 21 at the pressure contact portion or the closest portion to the photosensitive drum 21. When the toner 1 is supplied, a potential having a polarity opposite to the charging potential of the toner 1 is applied to the surface of the developing roller 243 as a developing bias voltage (developing bias). As a result, the toner 1 on the surface of the developing roller 243 is smoothly supplied to the electrostatic latent image. By changing the value of the developing bias, the amount of toner (toner adhesion amount) supplied to the electrostatic latent image can be controlled.

  The supply roller 244 is a member that faces the developing roller 243 and supplies toner 1 around the developing roller 243. The stirring roller 245 is a member that faces the supply roller 244 and feeds the toner 1 newly supplied from the toner hopper 242 into the developing tank 241 to the periphery of the supply roller 244. The toner hopper 242 is provided so that a toner replenishing port (not shown) provided at the lower part in the vertical direction communicates with a toner receiving port (not shown) provided at the upper part in the vertical direction of the developing tank 241. The toner 1 is replenished according to the toner consumption status 241. As another embodiment, the toner 1 may be directly replenished from each color toner cartridge without using the toner hopper 242.

  The cleaning unit 25 is a member that removes the toner 1 remaining on the surface of the photosensitive drum 21 after the toner image is transferred from the photosensitive drum 21 to the intermediate transfer belt 31 and cleans the surface of the photosensitive drum 21. is there. For the cleaning unit 25, for example, a plate-like member such as a cleaning blade is used. In the image forming apparatus 100, an organic photosensitive drum is mainly used as the photosensitive drum 21. Since the surface of the organic photosensitive drum is mainly composed of a resin component, the surface deterioration is likely to proceed due to the chemical action of ozone generated during charging, but the deteriorated surface portion is rubbed by the cleaning unit 25. It is worn out and is gradually but surely removed. Therefore, the problem of deterioration of the surface of the photosensitive drum 21 due to ozone or the like is practically solved, and the charging potential by the charging operation can be stably maintained over a long period of time. Although the cleaning unit 25 is provided in this embodiment, the cleaning unit 25 may not be provided.

  According to the toner image forming unit 20, the surface of the photosensitive drum 21 that is uniformly charged by the charging unit 22 is irradiated with laser light corresponding to image information from the exposure unit 23 to form an electrostatic latent image. . Toner 1 is supplied to the electrostatic latent image from developing device 24 to form a toner image, and the toner image is transferred to intermediate transfer belt 31. After the toner image is transferred to the intermediate transfer belt 31, the toner 1 remaining on the surface of the photosensitive drum 21 is removed by the cleaning unit 25. Such a series of toner image forming operations are repeatedly executed.

  The intermediate transfer belt 31 is an endless belt-like member that is disposed above the photosensitive drum 21 in the vertical direction. The intermediate transfer belt 31 is stretched by a driving roller 32 and a driven roller 33 to form a loop-shaped path, and is driven to rotate in the direction of an arrow B.

  The drive roller 32 is provided so that it can be rotated around its axis by a drive unit (not shown). The drive roller 32 drives the intermediate transfer belt 31 to rotate in the arrow B direction by rotational drive. The driven roller 33 is provided so as to be able to rotate following the rotational drive of the drive roller 32, and generates a certain tension on the intermediate transfer belt 31 so that the intermediate transfer belt 31 does not loosen.

  The intermediate transfer roller 34 is provided so as to be in pressure contact with the photosensitive drum 21 via the intermediate transfer belt 31 and to be rotatable around its axis by a drive unit (not shown). The intermediate transfer roller 34 is connected to a power source (not shown) for applying a transfer bias, and has a function of transferring the toner image on the surface of the photosensitive drum 21 to the intermediate transfer belt 31.

  The transfer roller 36 is provided so as to be in pressure contact with the drive roller 32 via the intermediate transfer belt 31 and to be rotatable around an axis by a drive unit (not shown). At the pressure contact portion (transfer nip portion) between the transfer roller 36 and the driving roller 32, the toner image carried and conveyed by the intermediate transfer belt 31 is transferred to a recording medium fed from a recording medium supply unit 50 described later. The

  The transfer belt cleaning unit 35 is provided so as to face the driven roller 33 through the intermediate transfer belt 31 and to be in contact with the toner image carrying surface of the intermediate transfer belt 31. If the toner 1 remains on the intermediate transfer belt 31 after the transfer of the toner image to the recording medium, the residual toner may adhere to the transfer roller 36 due to the rotation of the intermediate transfer belt 31. The toner 1 adhering to the transfer roller 36 causes the back surface of the recording medium to be transferred next to be contaminated. Therefore, the transfer belt cleaning unit 35 is provided to remove and collect the toner 1 on the surface of the intermediate transfer belt 31 after the transfer of the toner image to the recording medium.

  According to the transfer unit 30, when the intermediate transfer belt 31 rotates while being in contact with the photosensitive drum 21, a transfer bias having a polarity opposite to the charging polarity of the toner 1 on the surface of the photosensitive drum 21 is applied to the intermediate transfer roller 34. Then, the toner image formed on the surface of the photosensitive drum 21 is transferred onto the intermediate transfer belt 31. In the case of a full-color image, the toner images of the respective colors respectively formed on the photosensitive drum 21y, the photosensitive drum 21m, the photosensitive drum 21c, and the photosensitive drum 21b are sequentially transferred onto the intermediate transfer belt 31 in this order. As a result, a full-color toner image is formed. The toner image transferred to the intermediate transfer belt 31 is conveyed to the transfer nip portion by the rotational drive of the intermediate transfer belt 31, and transferred to the recording medium at the transfer nip portion. The recording medium to which the toner image is transferred is conveyed to the fixing unit 40.

  The recording medium supply unit 50 includes an automatic paper feeding unit 51, pickup rollers 52 a and 52 b, conveyance rollers 53 a and 53 b, a registration roller 54, and a manual paper feed tray 55. The automatic paper feeder 51 is a container-like member that is provided in the lower part of the image forming apparatus 100 in the vertical direction and stores a recording medium inside the image forming apparatus 100. The manual paper feed tray 55 is a tray-like member that stores a recording medium outside the image forming apparatus 100. Examples of the recording medium include plain paper, color copy paper, overhead projector sheet, and postcard.

  The pickup roller 52a is a roller-like member that takes out the recording medium stored in the automatic paper feeding unit 51 one by one and feeds it to the paper transport path A1. The transport rollers 53a are a pair of roller-like members provided so as to be in pressure contact with each other, and transport the recording medium toward the registration rollers 54 in the paper transport path A1. The pickup roller 52b is a roller-like member that takes out the recording medium stored in the manual paper feed tray 55 one by one and feeds it to the paper transport path A2. The transport rollers 53b are a pair of roller-like members provided so as to be in pressure contact with each other, and transport the recording medium toward the registration rollers 54 in the paper transport path A2.

  The registration rollers 54 are a pair of roller-like members provided so as to come into pressure contact with each other, and the toner image carried on the intermediate transfer belt 31 is conveyed to the transfer nip portion of the recording medium fed from the conveyance rollers 53a and 53b. In synchronization with this, the sheet is fed to the transfer nip portion.

  According to the recording medium supply unit 50, the recording medium is transferred from the automatic sheet feeding unit 51 or the manual sheet feeding tray 55 in synchronization with the toner image carried on the intermediate transfer belt 31 being conveyed to the transfer nip unit. The toner image is fed to the nip portion and the toner image is transferred to the recording medium.

  FIG. 5 is a schematic diagram schematically showing the configuration of the fixing unit 40. 5A is a front view of the fixing unit 40, FIG. 5B is a top view of the fixing unit 40 viewed from the I direction in FIG. 5A, and FIG. It is the left view which looked at from II direction of Fig.5 (a).

  The fixing unit 40 includes a laser fixing device 41 and a conveyance unit 44. The laser fixing device 41 includes a laser light source 42 and a rotating polygon mirror 43. The laser light source 42 is a member that irradiates laser light having a predetermined wavelength. The rotary polygon mirror 43 reflects the laser light emitted from the laser light source 42 and scans and exposes the recording medium from a direction substantially perpendicular to the toner carrying surface of the recording medium. For example, the rotary polygon mirror 43 has a regular hexagonal shape and rotates at a constant speed in the direction of the arrow C1. The laser fixing device 41 can locally irradiate the toner image on the recording medium with laser light.

  The conveyance unit 44 includes a conveyance belt 45, a driving roller 46, and a driven roller 47. The conveyor belt 45 is an endless belt-like member. The conveyor belt 45 is stretched by the driving roller 46 and the driven roller 47 to form a loop-shaped path, and is driven to rotate in the direction of the arrow C2. The conveyance belt 45 may be configured to carry and convey a recording medium on the belt surface by electrostatic force, or may be configured to carry and convey a recording medium on the belt surface by wind power.

  The drive roller 46 is provided such that it can be rotated around its axis by a drive unit (not shown). The drive roller 46 rotates the conveyance belt 45 in the direction of the arrow C2 by rotational driving. The driven roller 47 is provided so as to be able to rotate following the rotational drive of the drive roller 46, and generates a certain tension on the conveyor belt 45 so that the conveyor belt 45 does not loosen.

  A collimator lens, a cylinder lens, or the like may be provided in the optical path between the laser light source 42 and the rotary polygon mirror 43. Further, an fθ lens, a folding mirror, a reflection mirror, or the like may be provided between the rotating polygon mirror 43 and the conveyor belt 45.

  The laser fixing device 41 can fix the toner 1 on the recording medium in a non-contact manner by irradiating the unfixed toner image carried on the recording medium with laser light having a predetermined wavelength. Specifically, the colorant and the infrared absorber 4 contained in the unfixed toner 1 on the recording medium absorb the laser beam having a wavelength in the infrared region and generate heat, so that the toner 1 is heated and melted. And fixing on the recording medium.

The laser light source 42 is preferably irradiated with laser light having a wavelength of 780 nm to 1000 nm. The intensity of the laser emitted from the laser light source 42 is preferably in the range 1.5 W / cm ² or more 630 W / cm ² following. When the intensity of the laser is weaker than 1.5 W / cm ² , the toner 1 is not sufficiently melted by the laser irradiation, so that the fixing rate of the toner 1 is lowered. When the intensity of the laser is higher than 630 W / cm ² , the toner 1 or the recording medium is burned by the laser irradiation, and thereby the fixing rate of the toner 1 is lowered.

  According to the fixing unit 40, when a recording medium carrying an unfixed toner image is conveyed from the transfer nip unit to the conveyance unit 44, laser light having a wavelength in the infrared region is irradiated from the laser light source 42 to the unfixed toner image. Is done. The irradiated laser light is absorbed by the colorant and infrared absorber 4 contained in the toner 1. As a result, the toner 1 is heated and melted. When all the unfixed toner images are heated and melted, the toner images are fixed on the recording medium and an image is formed. The recording medium on which the toner image is fixed is conveyed to the discharge unit 60 by the conveyance unit 44.

  The discharge unit 60 includes a conveyance roller 61, a discharge roller 62, and a discharge tray 63. The conveyance roller 61 is a pair of roller-like members provided so as to be in pressure contact with each other in the vertical direction above the fixing unit 40. The conveyance roller 61 conveys the recording medium on which the image is fixed toward the discharge roller 62.

  The discharge roller 62 is a pair of roller-like members provided so as to be in pressure contact with each other. In the case of single-sided printing, the discharge roller 62 discharges the recording medium on which single-sided printing has been completed to the discharge tray 63. In the case of double-sided printing, the discharge roller 62 conveys the recording medium on which single-sided printing has been completed to the registration roller 54 via the paper conveyance path A3, and discharges the recording medium on which double-sided printing has been completed to the discharge tray 63. . The discharge tray 63 is provided on the upper surface in the vertical direction of the image forming apparatus 100 and stores a recording medium on which an image is fixed.

  Image forming apparatus 100 includes a control unit (not shown). The control unit unit is provided, for example, at an upper part in the vertical direction in the internal space of the image forming apparatus 100, and includes a storage unit, a calculation unit, and a control unit. In the storage unit of the control unit unit, various setting values via an operation panel (not shown) arranged on the upper surface in the vertical direction of the image forming apparatus 100, detection results from sensors (not shown) arranged at various locations inside the image forming apparatus 100, etc. Image information from an external device is input. A program for executing various processes is written in the storage unit. Examples of the various processes include a recording medium determination process, an adhesion amount control process, and a fixing condition control process.

  As the storage unit, those commonly used in this field can be used, and examples thereof include a read only memory (ROM), a random access memory (RAM), and a hard disk drive (HDD). As the external device, an electric or electronic device that can form or acquire image information and can be electrically connected to the image forming apparatus 100 can be used. For example, a computer, a digital camera, a television receiver, a video recorder DVD (Digital Versatile Disc) recorder, HDDVD (High-Definition Digital Versatile Disc) recorder, Blu-ray disc recorder, facsimile apparatus, portable terminal apparatus, and the like.

  The calculation unit retrieves various data (image formation command, detection result, image information, etc.) written in the storage unit and various processing programs, and performs various determinations. The control unit sends a control signal to the corresponding device according to the determination result of the calculation unit, and performs operation control.

The control unit and the calculation unit include a processing circuit realized by a microcomputer, a microprocessor, or the like provided with a central processing unit (CPU). The control unit unit includes a main power source together with the processing circuit described above, and the power source supplies power not only to the control unit unit but also to each member in the image forming apparatus 100.

  As described above, the developer containing the toner 1 according to the present invention is used in the image forming apparatus 100. The image forming apparatus 100 includes a toner image forming step for forming a toner image by supplying the toner 1 according to the present invention to an electrostatic latent image, a transfer step for sequentially transferring the toner images of the respective colors onto a recording medium, An image is formed by an image forming method including a fixing step of fixing the toner 1 to the recording medium by irradiating the toner 1 of each color on the recording medium with laser light having a wavelength in the infrared region.

[Glass transition temperature of amorphous polyester resin]
Using a differential scanning calorimeter (trade name: DSC220, manufactured by Seiko Denshi Kogyo Co., Ltd.), according to Japanese Industrial Standard (JIS) K7121-1987, 1 g of a sample is heated at a heating rate of 10 ° C. per minute and a DSC curve is measured. did. Draw the endothermic peak corresponding to the glass transition of the obtained DSC curve at a point where the slope is maximum with respect to the straight line that extends the base line on the high temperature side to the low temperature side and the curve from the rising part of the peak to the vertex. The temperature at the intersection with the tangent was determined as the glass transition temperature (Tg).

[Melting point of crystalline polyester resin and wax]
Using a differential scanning calorimeter (trade name: DSC220, manufactured by Seiko Denshi Kogyo Co., Ltd.), 1 g of a sample is heated from a temperature of 20 ° C. to 200 ° C. at a heating rate of 10 ° C. per minute, and then rapidly cooled from 200 ° C. to 20 ° C. The operation was repeated twice and the DSC curve was measured. The temperature of the endothermic peak corresponding to the melting of the DSC curve measured in the second operation was taken as the melting point.

[Volume average particle diameter of the wax added in the infrared absorbing agent]
To 50 ml of electrolyte (trade name: ISOTON-II, manufactured by Beckman Coulter, Inc.), 20 mg of sample and 1 ml of sodium alkyl ether sulfate are added, and an ultrasonic disperser (trade name: desktop type dual frequency ultrasonic cleaner VS- D100 (manufactured by ASONE Co., Ltd.) was used for dispersion treatment at a frequency of 20 kHz for 3 minutes to obtain a measurement sample. This sample for measurement was measured using a particle size distribution measuring apparatus (trade name: Multisizer 3, manufactured by Beckman Coulter, Inc.) under the conditions of aperture diameter: 100 μm, number of measured particles: 50000 count, and volume particle size of sample particles The volume average particle size was determined from the distribution.

<Example 1>
(First kneading step)
Ester wax (trade name: ECOSOLE, melting point 75 ° C., latent heat 150 J / g, manufactured by Nippon Seiki Co., Ltd.) 7.5 parts by weight Infrared absorber (trade name: NK-4680, Hayashibara Biochemical Laboratories, Inc.) Made)
0.7 parts by weight

  The above toner raw materials were mixed with a Henschel mixer (trade name: FM20C, manufactured by Mitsui Mining Co., Ltd.) to obtain a mixture. Using a twin-screw extrusion kneader (trade name: PCM65, manufactured by Ikegai Co., Ltd.), the mixture is melt-kneaded at 75 ° C., the melt-kneaded product is cooled and solidified, and pulverized with a feather mill to add an infrared absorbing wax. Got. The volume average particle diameter of the infrared absorbing agent-added wax is 1 mm.

(Second kneading step)
・ Infrared absorbing wax 8.2 parts by weight ・ Crystalline polyester resin (trade name: FC1495, manufactured by Mitsubishi Rayon Co., Ltd., melting point 50 ° C.) 60 parts by weight ・ Amorphous polyester resin (trade name: FC1496, Mitsubishi rayon) Co., Ltd., glass transition temperature 62 ° C.) 40 parts by weight Colorant (trade name: CI Pigment Blue 111, manufactured by DIC Corporation)
5 parts by weight Charge control agent (trade name: BONTRON E-84, manufactured by Orient Chemical Co., Ltd.)
1.5 parts by weight

  The toner material was melt-kneaded at 150 ° C. using a twin-screw extrusion kneader (trade name: PCM65, manufactured by Ikegai Co., Ltd.) to obtain a toner kneaded product.

(Crushing process)
The toner kneaded product is coarsely pulverized with a cutting mill (trade name: VM-16, manufactured by Orient Co., Ltd.), then finely pulverized with a jet mill (manufactured by Hosokawa Micron Co., Ltd.), and further with an air classifier (manufactured by Hosokawa Micron Co., Ltd.). By classifying, a toner having a volume average particle diameter of 6.9 μm was obtained. 100 parts by weight of the toner thus obtained, 0.7 parts by weight of silica particles having an average primary particle diameter of 20 nm hydrophobized with a silane coupling agent, and 0.5 parts by weight of titanium oxide are mixed. Thus, the toner of Example 1 was obtained.

<Example 2>
A toner of Example 2 was obtained in the same manner as in Example 1 except that the addition amount of the crystalline polyester resin was changed to 50 parts by weight and the addition amount of the amorphous polyester resin was changed to 50 parts by weight.

<Example 3>
A toner of Example 3 was obtained in the same manner as in Example 1 except that the addition amount of the crystalline polyester resin was changed to 70 parts by weight and the addition amount of the amorphous polyester resin was changed to 30 parts by weight.

<Example 4>
A toner of Example 4 was obtained in the same manner as in Example 1 except that the addition amount of the crystalline polyester resin was changed to 80 parts by weight and the addition amount of the amorphous polyester resin was changed to 20 parts by weight.

<Example 5>
A toner of Example 5 was obtained in the same manner as in Example 1 except that the addition amount of the wax was changed to 5 parts by weight.

<Example 6>
A toner of Example 6 was obtained in the same manner as in Example 1 except that the addition amount of the wax was changed to 10 parts by weight.

<Example 7>
Example 1 except that an amorphous polyester resin having a glass transition temperature of 60 ° C. (trade name: FC1497, manufactured by Mitsubishi Rayon Co., Ltd.) was used instead of the amorphous polyester resin having a glass transition temperature of 65 ° C. Thus, a toner of Example 7 was obtained.

<Example 8>
Example in the same manner as in Example 1 except that microcrystalline wax (trade name: Hi-Mic-1045, manufactured by Nippon Seiki Co., Ltd.) having a melting point of 70 ° C. was used instead of the ester wax having a melting point of 75 ° C. 8 toner was obtained.

<Comparative Example 1>
Comparative Example 1 was performed in the same manner as in Example 1 except that a crystalline polyester resin having a melting point of 80 ° C. (trade name: FC1498, manufactured by Mitsubishi Rayon Co., Ltd.) was used instead of the crystalline polyester resin having a melting point of 50 ° C. No toner was obtained.

<Comparative example 2>
Example 1 except that an amorphous polyester resin having a glass transition temperature of 80 ° C. (trade name: FC1499, manufactured by Mitsubishi Rayon Co., Ltd.) was used instead of the amorphous polyester resin having a glass transition temperature of 65 ° C. Similarly, a toner of Comparative Example 2 was obtained.

<Comparative Example 3>
No ester wax was used, the first kneading step was not performed, and in the second kneading step, an infrared absorber was used in place of the infrared absorbing agent-added wax. A toner was obtained.

  In Examples 1-8 and Comparative Examples 1-3, the melting point of the crystalline polyester resin, the glass transition temperature of the amorphous polyester resin, the content of each of the crystalline polyester resin and the wax relative to the binder resin, the type of wax, The melting point of the wax is summarized in Table 1.

  The toner of Examples and Comparative Examples and a ferrite core carrier (volume average particle size 60 μm) were adjusted to a toner concentration of 7% by weight (a weight mixing ratio of the toner relative to the total weight of the developer). A two-component developer containing the toners of Examples and Comparative Examples was prepared by charging into a cylindrical container and mixing and stirring at 100 rpm for 1 hour on a biaxially driven polybottle gantry.

<Evaluation>
Using a machine in which a fixing device of a commercial copying machine (trade name: MX-2700, manufactured by Sharp Corporation) is modified to the fixing unit 40 shown in FIGS. 5A to 5C, a semiconductor laser is used under the following conditions. Fixing was performed using

  The wavelength of the infrared laser (semiconductor laser) was set to 808 nm, and the scan speed was set to 7100 mm / s.

  The DC bias value of the bias voltage applied to the developer carrying member was appropriately changed depending on the charge amount of the toner in each two-component developer, and adjusted so that the image density of the solid image became a specified value. Further, the toner consumption amount due to visible image formation was detected by a toner density sensor as a change in toner density. Since the consumed toner is replenished from the toner hopper until the specified toner concentration is reached, each toner concentration in the two-component developer inside the developing unit is kept substantially constant.

  The laser output value was set to 30 W, and the toner image was fixed on the recording medium on which the toner image having a coverage of 5% was formed, and an image sample was obtained. Using this image sample, white spots and fixability of the image were evaluated.

(Outline of image)
The presence or absence of white spots in the image portion of the image sample was visually confirmed.

The evaluation criteria for white spots in the image are as follows.
○: Good. There are no white spots in the image area.
Δ: No problem in actual use. One or two white spots are confirmed in the image portion.
X: Three or more white spots are confirmed in the image portion.

(Fixability)
The surface of a plurality of image samples is rubbed back and forth three times with a sand eraser with a load of 1 kg in a Gakushin fastness tester, and the optical reflection density (image density) before and after rubbing is applied to a reflection densitometer (Macbeth). Measured. Next, the fixing rate (%) was calculated by the following formula (1) to evaluate the fixing property.
Fixing rate (%) = {(image density after rubbing) / (image density before rubbing)} × 100 (1)

The evaluation criteria for fixability are as follows.
○: Good. The fixing rate is 80% or more.
Δ: No problem in actual use. The fixing rate is 70% or more and less than 80%.
X: Defect. The fixing rate is less than 70%.

Table 2 shows the evaluation results of white spots and fixability of the image.

  In the toners of Examples 1 to 8, almost no white spots were observed in the image, and generation of voids could be suppressed. Further, an image having a sufficient fixing strength could be formed even when the fixing temperature was low and the irradiation energy from the infrared laser was small.

  In the toner of Comparative Example 1, since the melting point of the crystalline polyester resin is higher than the melting point of the wax, the binder resin does not sufficiently penetrate between the fibers of the recording medium, and the fixing property is lowered.

  In the toner of Comparative Example 2, since the glass transition temperature of the amorphous polyester resin was higher than the melting point of the wax, the binder resin did not sufficiently penetrate between the fibers of the recording medium, and the fixability was lowered.

  Since the toner of Comparative Example 3 did not use wax, the heat storage effect was not obtained, and the binder resin did not sufficiently penetrate between the fibers of the recording medium, resulting in a decrease in fixability.

1 Toner 2 Binder Resin 3 Wax 4 Infrared Absorber 5 Infrared Absorbent Wax

Claims (5)

A colorant;
With wax,
An infrared absorber internally added to the wax;
An infrared laser comprising: a crystalline polyester resin having a melting point lower than that of the wax; and a binder resin made of an amorphous polyester resin having a glass transition temperature lower than the melting point of the wax. Toner for fixing.   2. The infrared laser fixing toner according to claim 1, wherein the binder resin contains the crystalline polyester resin in a proportion of 50 wt% to 80 wt%.   The infrared laser fixing toner according to claim 1, wherein the wax is contained in a ratio of 5 wt% to 10 wt% with respect to the binder resin.   The infrared laser fixing toner according to claim 1, wherein the wax is an ester wax. A first kneading step of melt-kneading a mixture of a wax and an infrared absorber to obtain an infrared absorber-added wax;
Toner kneading by melting and kneading the infrared absorbing wax, a crystalline polyester resin having a melting point lower than that of the wax, and an amorphous polyester resin having a glass transition temperature lower than that of the wax. A second kneading step for obtaining a product,
And a pulverizing step of pulverizing the toner kneaded product.

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