JP4941660B2 - One-component non-magnetic toner and image forming apparatus using the toner - Google Patents

Description

  The present invention relates to a toner applied to a non-contact developing system and an image forming apparatus using the toner.

  Conventionally, as an image forming apparatus, a photosensitive member such as a photosensitive drum or a photosensitive belt, which is a latent image carrier, is rotatably supported on the main body of the image forming apparatus. After forming the latent image, the latent image is visualized with toner by a contact method or a non-contact method, and then the visible image is directly transferred to a transfer material using a corona transfer or a transfer roller. There is a method in which a visible image is once transferred to an intermediate transfer medium such as a transfer drum or a transfer belt, and then retransferred to a transfer material.

  As a color image forming apparatus, a method is known in which a plurality of photoconductors and developing mechanisms are used, and a visualized image on a transfer belt or a transfer drum is transferred onto a transfer material such as paper by sequentially superimposing and transferring a plurality of color images. It has been. In these systems, those using belts are classified as tandem systems, and those using drums are classified as transfer drum systems. In addition, an intermediate transfer method is also known in which a color image is sequentially primary transferred onto an intermediate transfer medium, and the primary transfer images are collectively transferred onto a transfer material.

  In these image forming apparatuses, two-component toner is generally known as the toner, and relatively stable development is possible. However, a change in the mixing ratio between the developer and the magnetic carrier is likely to occur. It is necessary to maintain it. Therefore, one-component magnetic toner has been developed, but there is a problem that a clear color image cannot be obtained due to the opacity of the magnetic material. On the other hand, in the case of a one-component non-magnetic toner, in order to obtain a high-quality recorded image by repeating the above-described steps, there is a problem of how to uniformly charge the toner while having high fluidity. In particular, when applied to a non-contact AC developing system, it is necessary to improve the fluidity of the toner from the viewpoint of improving the flying property and weaken the adhesive force of the toner to the developing roller. From the viewpoint of improving the flight performance, it is necessary to release excessive triboelectric charges accumulated in the toner.

In conventional one-component non-magnetic toners, it is known that silica fine particles are externally added as a fluidity improver. However, the silica fine particles are charged up upon charging due to high resistance of 10 ¹⁵ Ω · cm or more. There is a problem that a phenomenon occurs and the image density is lowered by repeating the image forming process. It is also known that titania particles or alumina particles are externally added from the viewpoint of releasing excessive triboelectric charge accumulated in the toner and enhancing the flying property by the developing electric field.

  In recent years, toners for oilless fixing devices in which a release agent such as wax is contained in the toner base particles in a proportion of 1 to 10% by weight have been developed. In such toners, the wax component has a weak stress. However, there is a problem in that the external additive particles adhering to the toner surface are buried, and the flying durability is deteriorated. For this reason, the embedding of the fine silica particles having a large particle diameter with the use of the fine silica particles having a spacer function is suppressed, but the addition of the large silica fine particles reduces the fluidity and the toner charge amount. There arises a problem such as an increase in the air travel, and similarly there is a problem in that the flightability is deteriorated.

  Further, when titania fine particles are used as an external additive, they function as a charge control agent that releases excessive charges, but there are problems that weakly charged toner is generated and fogging occurs and the amount of toner scattering increases. In particular, in the non-contact AC development method, since the toner is clouded between the development gaps, the toner is likely to be scattered due to the airflow that cools the inside of the apparatus, and the toner is easily contaminated. The toner added with titania fine particles is likely to be scattered. . In addition, since anatase titania fine particles are needle-shaped or plate-shaped, they are buried in the toner base particles even under weak stress, causing the flying durability to deteriorate in the same way as small silica. There is.

The present applicant previously described two types of hydrophobic silica particles having different average primary particle sizes of 7 to 12 nm and 40 to 50 nm and spindle-shaped rutile-anatase type titanium oxide particles as external additives. Although a relatively clean image is formed at the initial stage (Patent Document 1), the toner is developed from a developing roller, a regulating member, or the like, starting from a wax portion exposed on the toner surface when printing a large number of sheets. Also, streaks (colorant filming) that adhere to the upper seal member and are colored are visually observed on each member, causing development roller filming and upper seal filming, and when a solid image is printed on the entire surface, It was found that striped stripes and minute pitch unevenness occur in the direction (exposure sub-scanning direction). Such a problem is particularly noticeable when colored particles containing toner (toner base particles) are produced by associating and coalescing aggregated particles by an emulsion aggregation method or a phase inversion emulsion coalescence method. It also turned out to be.
Patent No. 3,661,780

  SUMMARY OF THE INVENTION An object of the present invention is to provide a one-component nonmagnetic toner that does not cause coloring filming during durability and to provide an image forming apparatus thereof.

The one-component nonmagnetic toner of the present invention comprises at least colored particles containing a binder resin, a colorant and a release agent, and an external additive. The external additive is at least based on 100 parts by mass of the colored particles. Rutile type (10%), anatase type (90%), spherical to spindle-shaped hydrophobic rutile-anatase type titanium oxide particles having a major axis diameter of 20 to 50 nm, 0.5 to 2.0 parts by mass, number primary average particle 0.5 to 2.0 parts by mass of hydrophobic monodisperse spherical large silica particles having a diameter of 100 nm and 0.5 to 3.0 parts by mass of hydrophobic small silica particles having a number average primary particle size of 12 nm ; It is characterized by doing.
The particle size of the external additive is derived from an image projected by a transmission electron microscope (TEM) through an image processing apparatus.

  The external additive is added after the hydrophobic rutile-anatase-type titanium oxide particles and the hydrophobic monodispersed spherical large silica particles are externally added to the colored particles and then externally treated with the hydrophobic small silica particles. Features.

The colored particles are obtained by an emulsion aggregation method or a phase inversion emulsion coalescence method, have a volume average particle diameter (D ₅₀ ) of 4.0 to 7.0 μm, and contain 3 to 10% by mass of a release agent. And

  Hydrophobic monodisperse spherical large silica particles are characterized by being hydrophobized with silicone oil.

An image forming apparatus according to the present invention includes a photosensitive member carrying an electrostatic latent image, and is opposed to the photosensitive member in a non-contact state, and at least binds the electrostatic latent image carried on the photosensitive member. It consists of colored particles containing a resin, a colorant and a release agent and an external additive. As the external additive, with respect to 100 parts by mass of the colored particles, a rutile type (10%), an anatase type (90%), 0.5 to 2.0 parts by mass of spherical to spindle-shaped hydrophobic rutile-anatase-type titanium oxide particles having a major axis diameter of 20 to 50 nm , and 0 of hydrophobic monodispersed spherical large silica particles having a number average primary particle size of 100 nm .5 to 2.0 parts by mass, a metal that develops by carrying a one-component non-magnetic toner in which a hydrophobic small silica particle having a number primary average particle size of 12 nm is added in an amount of 0.5 to 3.0 parts by mass A developing roller having a surface and a developing roller disposed in pressure contact with the developing roller and rotating And a supply roller made of an elastic body that supplies the toner to the developing roller. The peripheral speed of the supply roller is set to 400 to 600 mm / s, and the peripheral speed ratio indicated by the supply roller peripheral speed / the development roller peripheral speed is It is characterized by comprising a developing device of 1.3 to 1.8.
The particle size of the external additive is derived from an image projected by a transmission electron microscope (TEM) through an image processing apparatus.

  The one-component non-magnetic toner is characterized in that the thin layer is regulated to have a layer thickness of 1 to 2 on the developing roller.

As the colored particles (toner mother particles) in the present invention, toner mother particles obtained by a pulverization method can be used, but the colored particles having a small particle diameter of 4.0 to 7.0 μm in volume average particle diameter (D ₅₀ ). Therefore, it is preferably obtained by an emulsion aggregation method or a phase inversion emulsification coalescence method.

  In the emulsion aggregation method, polymerization is performed by dispersing monomers, polymerization initiators, emulsifiers (surfactants), etc. in water, and a dispersion consisting of the formed resin particles, a colorant, a release agent and necessary In accordance with the above, a charge control agent or the like and a dispersion liquid such as an aggregating agent (electrolyte) are mixed to obtain colored particles that are aggregated and heat-fused. The colored particles obtained in this way are preferably mixed with a dispersion of resin particles, and the colored particles are used as a core to attach and heat fuse the resin particles to form a coating (shell) to form a core-shell structure. The exposure of the mold component to the surface of the colored particles can be prevented to further prevent the wax (release agent) component from adhering to the developing roller or the like, and toner mother particles excellent in filming prevention can be obtained.

  Examples of the monomer in the emulsion aggregation method toner include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-methoxystyrene, p-ethylstyrene, vinyltoluene, and 2,4. -Dimethylstyrene, pn-butylstyrene, p-phenylstyrene, p-chlorostyrene, divinylbenzene, methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, acrylic acid n- Octyl, dodecyl acrylate, hydroxyethyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, meta Isobutyl toluate, n-octyl methacrylate, dodecyl methacrylate, hydroxyethyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, acrylic acid, methacrylic acid, maleic acid, fumaric acid, cinnamic acid, ethylene Glycol, propylene glycol, maleic anhydride, phthalic anhydride, ethylene, propylene, butylene, isobutylene, vinyl chloride, vinylidene chloride, vinyl bromide, vinyl fluoride, vinyl acetate, vinyl propylene acid, acrylonitrile, methacrylonitrile, vinyl methyl ether , Vinyl ethyl ether, vinyl ketone, vinyl hexyl ketone, vinyl naphthalene and the like. Among these, a styrene allyl copolymer is preferable from the viewpoint of chargeability.

  Further, as a colorant, carbon black, lamp black, magnetite, titanium black, chrome yellow, ultramarine blue, aniline blue, phthalocyanine blue, phthalocyanine green, hansa yellow G, rhodamine 6G, calco oil blue, quinacridone, benzidine yellow, rose bengal, Malachite Green Lake, Quinoline Yellow, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 184, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 180, C.I. I. Solvent Yellow 162, C.I. I. Pigment blue 5: 1, C.I. I. Dye and pigment such as CI Pigment Blue 15: 3 can be used alone or in combination.

  Examples of the mold release agent include paraffin wax, micro wax, micro crystallin wax, cadilla wax, carnauba wax, rice wax, montan wax, polyethylene wax, polypropylene wax, oxidized polyethylene wax, oxidized polypropylene wax and the like. Among these, it is preferable to use polyethylene wax, polypropylene wax, carnauba wax, ester wax and the like.

  It is preferable not to add the charge control agent because it affects the aggregation / aggregation of the aggregated particles in the emulsion aggregation or phase inversion emulsion coalescence method, and becomes a hindrance in obtaining a desired particle structure. Toner base particles that do not contain a preparation (CCA-less toner) are used as long as they do not have the above-described effects. For example, oil black, oil black BY, Bontron S-22 (manufactured by Orient Chemical Co., Ltd.), Bontron S-34 (produced by Orient Chemical Co., Ltd.), salicylic acid metal complex E-81 (produced by Orient Chemical Co., Ltd.), thioindigo pigment, sulfonylamine derivative of copper phthalocyanine, Spiron Black TRH (Hodogaya Chemical Co., Ltd.) Co., Ltd.), calixarene compounds, organic boron compounds, fluorine-containing quaternary ammonium salt compounds, monoazo gold Complex, aromatic hydroxycarboxylic acid metal complexes, aromatic dicarboxylic acid metal complex, a polysaccharide or the like may be added.

  Examples of the polymerization initiator in the emulsion aggregation method include potassium persulfate, sodium persulfate, ammonium persulfate, hydrogen peroxide, 4,4′-azobiscyanovaleric acid, t-butyl hydroperoxide, benzoyl peroxide, 2,2 '-Azobis-isobutyronitrile and the like.

  Examples of the emulsifier (surfactant) include sodium dodecylbenzene sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, potassium stearate, calcium oleate, dodecyl ammonium chloride, dodecyl ammonium bromide. , Dodecyl trimethyl ammonium bromide, dodecyl pyridinium chloride, hexadecyl trimethyl ammonium bromide, dodecyl polyoxyethylene ether, hexadecyl polyoxyethylene ether, lauryl polyoxyethylene ether, sorbitan monooleate polyoxyethylene ether, and the like.

  Examples of the flocculant (electrolyte) include sodium chloride, potassium chloride, lithium chloride, magnesium chloride, calcium chloride, sodium sulfate, potassium sulfate, lithium sulfate, magnesium sulfate, calcium sulfate, zinc sulfate, aluminum sulfate, and iron sulfate. Can be mentioned.

  The component ratio of the colored particles (toner base particles) is 3 to 10 parts by weight, preferably 4 to 8 parts by weight with respect to 100 parts by weight of the polymerization monomer, and 3 to 15 parts by weight for the colorant. If it is added, the charge control agent is 0.1-3 parts by mass.

  Moreover, as a polymerization initiator in emulsion polymerization, it is 0.03-2 mass parts with respect to 100 mass parts of polymerization monomers, Preferably it is 0.1-1 mass part, As an emulsifier (surfactant), 0.01- As 0.1 mass part and a flocculant (electrolyte), it is 0.05-5 mass parts, Preferably it is used in the ratio of 0.1-2 mass parts.

  Further, the colored particles (toner base particles) in the present invention may be obtained by a phase inversion emulsification coalescence method. The phase inversion emulsification coalescence method is described in, for example, Japanese Patent No. 3,867,893. (1) An aqueous medium is obtained by emulsifying a mixture containing at least a polyester resin and an organic solvent in an aqueous medium. A first step of forming fine particles of the mixture therein, and then (2) a second step of adding a dispersion stabilizer and further adding electrolyte sequentially to combine the fine particles to produce an aggregate of fine particles, ( 3) After removing the organic solvent contained in the aggregate, fine particles are separated from the aqueous medium, washed, and then dried to sequentially perform a third step.

  In addition, when a styrene acrylic resin is used as the binder resin, it can be made into a binder resin having excellent charge stability due to its excellent moisture resistance, and when it is a polyester resin, it is excellent in transparency of the obtained image and suitable for a color image. I can do it.

  Unlike the suspension polymerization toner, the colored particles obtained by the emulsion aggregation method and the colored particles obtained by the phase inversion emulsion coalescence method undergo a coalescing particle coalescence step. The release agent component is destroyed from the agglomerated grain boundary due to the stress during development, and the release agent component is exposed at the partial defect portion, and the exposed release agent component is transferred to the developing roller and the transferred release agent component (wax) is This is considered to be the starting point where colored film adheres and accumulates when printing many sheets and color filming is likely to occur.

The particle size of the colored particles in the present invention (toner mother particles), the 50% volume average particle size as measured by Coulter "Multisizer TAIII" type (D ₅₀₎ is 4.0～7.0Myuemu, preferably 5 ~ 6 μm. When the average particle diameter is 7 μm or less, even if a latent image is formed with a high resolution of 1200 dpi or more, the reproducibility of resolution can be excellent. When the thickness is 4 μm or less, the concealability by the toner is lowered due to a decrease in development efficiency, and the use amount of the external additive is increased to improve the fluidity, and as a result, the fixing performance tends to be lowered. .

  Next, the external additive will be described.

  The external additives in the present invention are at least (1) hydrophobic small silica particles, (2) hydrophobic monodispersed spherical large silica particles, and (3) hydrophobic rutile-anatase type titanium oxide particles.

  (1) The hydrophobic small silica particles have a number average primary particle diameter of 7 to 16 nm, preferably 10 to 12 nm. Examples are those obtained by vapor phase oxidation (dry method) of silicon halogen compounds. The smaller the number average primary particle diameter of the hydrophobic small silica particles, the higher the fluidity of the obtained toner. However, when the number average primary particle diameter is smaller than 7 nm, the silica fine particles are embedded in the toner base particles when externally added. Conversely, if the number average primary particle diameter exceeds 16 nm, the fluidity may be deteriorated.

  The hydrophobic small silica particles are added in an amount of 0.5 to 3.0 parts by mass, preferably 1.0 to 1.5 parts by mass with respect to 100 parts by mass of the toner base particles. When the amount is less than 0.5 parts by mass, the fluidity is deteriorated. When the amount is more than 3.0 parts by mass, there is a problem of photoconductor filming or fixing failure.

As the hydrophobic small silica particles, “RX200” manufactured by Nippon Aerosil Co., Ltd. (crystal form is amorphous, spherical, number average primary particle diameter is 12 nm, hydrophobized (surface) treatment with hexamethyldisilazane, true specific gravity is 2 .2, Bulk specific gravity: 0.02-0.06, BET specific surface area 140-200 m ² / g, Carbon amount 1.5-3.0%, Two component charge amount (5 min value) -100-100-300 μC / g In addition, “R805” (number average primary particle diameter of 12 nm) and the like are exemplified.

  Next, (2) the hydrophobic monodispersed spherical large silica particles have a number average primary particle size of 50 to 250 nm, preferably 80 to 150 nm. Hydrophobic monodisperse spherical large silica particles are spherical with a Wadell sphericity of 0.6 or more, preferably 0.8 or more. Monodispersed spherical silica fine particles are obtained by a sol-gel method that is a wet method, and have a specific gravity of 1.3 to 2.1. When the hydrophobic monodisperse spherical large silica particles have an average particle size of less than 50 nm, it becomes impossible to maintain the fluidity and charging stability by preventing the embedding of the fine particles of silica particles on the surface of the toner base particles. In addition, the spacer effect cannot be obtained, and if it is larger than 250 nm, it is difficult to adhere to the toner base particles and to be easily detached from the surface of the toner base particles.

  The hydrophobic monodispersed spherical large silica particles are added in an amount of 0.5 to 2.0 parts by weight, preferably 0.8 to 1.8 parts by weight, based on 100 parts by weight of the toner base particles. Although depending on the amount of hydrophobic small silica particles added, if the amount of hydrophobic monodispersed spherical large silica particles is less than 0.5 parts by mass, the toner packing density increases, and the toner layer is pushed by a regulating blade when the developing roller rotates. When regulating the thickness of the toner, it is difficult to make the toner thinner, resulting in problems of regulation leakage and scattering. If the amount of addition exceeds 2.0 parts by mass, when the toner layer passes through the regulating blade during rotation of the developing roller, a part of the toner leaks without being held by the developing roller, or the thin layer is regulated on the developing roller. In the toner layer, striped stripes occur in the longitudinal direction of the developing roller, and when a full-color image is output, there arises a problem that a large number of striped striped stripes occur due to density fluctuation in the paper feed direction.

Hydrophobic monodispersed spherical large silica particles include “Seahoster KE-P10S2” (manufactured by Nippon Shokubai Co., Ltd.) (crystalline is considered to be partly crystalline, spherical, number average primary particle size is 100 nm, silicone oil Hydrophobized (surface) treatment, true specific gravity 2.3, bulk specific gravity 0.25 to 0.35, BET specific surface area 10 to 14 m ² / g, two component charge amount (5 min value) 0 to −50 μC / g ) Is exemplified.

  The addition ratio (mass ratio) of the large particle size silica (2) to the small particle size silica (1) may be 1: 4 to 4: 1, preferably 2: 3 to 3: 2. It is preferable for imparting fluidity to the film and obtaining long-term charging stability. The large particle size silica and the small particle size silica are in a total amount of 1.25 to 5.0 parts by mass, preferably 2.0 to 3.0 parts by mass with respect to 100 parts by mass of the toner base particles in consideration of the mixing ratio of both. Part by mass is added.

  The silica fine particles are preferably hydrophobized. By making the surface of the negatively chargeable silica fine particles hydrophobic, the fluidity and chargeability of the toner are further improved. Hydrophobization of silica fine particles can be achieved by using silane compounds such as aminosilane, hexamethyldisilazane and dimethyldichlorosilane; or dimethyl silicone, methylphenyl silicone, fluorine-modified silicone oil, alkyl-modified silicone oil, amino-modified silicone oil, epoxy-modified silicone oil, etc. This silicone oil is used, for example, by a method commonly used by those skilled in the art, such as a wet method or a dry method.

  Next, (3) rutile-anatase type titanium oxide particles are obtained by the production method disclosed in JP-A-2000-128534, have a spherical to spindle shape and a major axis diameter of 20 to 100 nm, and Rutile-type titanium oxide particles in which rutile-type titanium oxide particles having a major axis to minor axis ratio of 2 to 8 are coated with spherical anatase-type titanium oxide particles having a number primary average particle size of 20 to 30 nm. : Anatase type titanium oxide particles (weight ratio) = 5: 95 to 50:50. Rutile-type titanium oxide particles are excellent in friction resistance due to their particle size and shape, and are difficult to embed in colored particles, and anatase-type titanium oxide particles are excellent in adhesion to colored particles and fluidity, It is excellent in affinity with the silane coupling agent, and the features of both can be utilized by coating at a certain ratio. The resulting rutile-anatase-type titanium oxide particles can be externally added particles having a uniform charge distribution, excellent dispersibility, and difficult to be embedded in colored particles by friction. The rutile-anatase type titanium oxide particles may be further subjected to a hydrophobic treatment with hexamethylsilazane, silicon oil or the like after the silane coupling treatment.

Examples of the hydrophobic rutile-anatase type titanium oxide particles include “STT-30S” {rutile type (10%): anatase type (90%) manufactured by Titanium Industry Co., Ltd. Spindle type, isobutyltrimethoxysilane treatment, true specific gravity 4.5, bulk specific gravity 0.15 to 0.35, BET specific surface area 120 to 160 m ² / g, two component charge amount 0 to −50 μC / g (5 min value)} Illustrated.

  Either or both of the hydrophobic rutile-anatase type titanium oxide particles and the above-described hydrophobic monodispersed spherical large silica particles may be treated with silicon oil. For example, the hydrophobic monodispersed spherical large silica particles may be treated with silicon oil. Then, although the detailed reason is unknown, it can be easily attached to the colored particles at the time of rearrangement of the colored particles on the cracked surface, and filming can be prevented more effectively.

  Hydrophobic rutile-anatase type titanium oxide particles are added in an amount of 0.5 to 2.0 parts by mass, preferably 1.0 to 1.5 parts by mass with respect to 100 parts by mass of the colored particles. When the amount is less than 0.5 parts by mass, there is a problem of image density reduction due to a charge-up phenomenon, and when the amount is more than 2.0 parts by mass, there are problems of regulation leakage and scattering of the upper seal.

  As a method for adding the external additive to the toner base particles, it is preferable to use a Henschel mixer (manufactured by Mitsui Miike Co., Ltd.), a mechano-fusion system (manufactured by Hosokawa Micron Co.), a mechano mill (manufactured by Okada Seiko Co., Ltd.) or the like. When multistage processing is performed using a Henschel mixer, the processing operation conditions at each stage are appropriately selected from the range of a rotational peripheral speed of 30 to 50 m / s and a processing time of 2 to 15 minutes.

  In the present invention, the order of addition of the external additives is that the colored particles are first treated with hydrophobic rutile-anatase-type titanium oxide particles, and the hydrophobic small silica particles are treated together with the hydrophobic monodispersed spherical large silica particles as the subsequent treatment. Two-stage external addition treatment may be performed, but particularly preferably, the colored particles are first treated with hydrophobic monodispersed spherical large silica particles and hydrophobic rutile-anatase-type titanium oxide particles, followed by hydrophobic treatment as a subsequent treatment. A two-stage external addition treatment for treating and adhering the silica particles may be performed, and the occurrence of colored filming in the durability test can be reduced.

  As described above, the colored particles obtained by the emulsion aggregation method and the colored particles obtained by the phase inversion emulsification coalescence method, unlike the suspension polymerization toner, go through a coalescence particle coalescing step, so a large number of sheets can be printed. In terms of durability, the release agent component is destroyed from the agglomerated grain boundary due to stress during development, and the release agent component is exposed at the partial defect portion, and the exposed release agent component is transferred to the developing roller and the like, and the transferred release agent The component (wax) is the starting point, and colored film adheres and accumulates when a large number of sheets are printed, and colored filming is likely to occur. Among external additives, hydrophobic rutile-anatase type titanium oxide particles have low adhesion to colored particles, and when hydrophobic monodisperse spherical large silica particles are externally added simultaneously with hydrophobic rutile-anatase type titanium oxide particles, Although the detailed reason is unknown, the adhesion of the hydrophobic monodispersed spherical large silica particles to the colored particles is controlled, and the hydrophobic monodispersed spherical large silica particles are re-applied to the fracture surface where the colored particles are cracked during durability. It is thought that arrangement is possible. This is because the hydrophobic monodispersed spherical large silica particles were re-established from the electron micrographs of the colored particle images before and after the endurance in the examples in the partially missing portion of the aggregated particles from the grain boundary in the colored particles after the endurance. It can be seen that they are arranged and cover their fractured surfaces, which can reduce the occurrence of colored filming.

  On the other hand, for example, when three people are externally added to the colored particles at the same time, as will be apparent from the description of Examples described later, although certain effects are recognized, filming occurs and local (peaky) occurs. There arises the problem of density unevenness due to fine unevenness due to fluctuations in the transport amount and filming of the developing roller. In addition, the hydrophobic monodispersed spherical large silica particles are first externally added to the colored particles as the order of addition, and the hydrophobic rutile-anatase type titanium oxide particles are externally added to the second stage, although a certain effect is recognized, Durability of hydrophobic monodispersed spherical large silica particles before the realignment of the colored monodispersed spherical large silica particles to the broken fracture surface of the colored particles may be hindered. There is a problem that filming occurs at an early stage and a strong vertical streak is generated in the paper traveling direction.

In addition, in the present invention, other hydrophobized external additives, for example, hydrophobic medium silica particles {fumed silica, “RX50” manufactured by Nippon Aerosil Co., Ltd., within a range that does not impair the purpose of adding the external additive particles described above. “True specific gravity 2.2, volume average particle diameter D ₅₀ = 40 nm (standard deviation = 20 nm)}, a metal salt selected from zinc, magnesium, calcium and aluminum of higher fatty acids which are metal soap particles, magnesium stearate, Calcium stearate, zinc stearate, monoaluminum stearate, trialuminum stearate, etc. may be externally added, and metals such as zinc oxide, strontium oxide, tin oxide, zirconia oxide, magnesium oxide, indium oxide, and alumina Fine particles of oxide, fine particles of nitride such as silicon nitride, carbide such as silicon carbide Fine particles of resin, resin particles, fine particles of metal salts such as calcium sulfate, barium sulfate, and calcium carbonate, and inorganic fine particles such as a composite thereof may be added.

Further, the total amount of the external additive particles added to the colored particles (toner base particles) is 58 to 304% in the external additive coverage (%, S × 100) according to the following formula (1) under the four-sided close-packed condition. It is processed as follows.

In the formula, external additive type (n types) n
Toner particle size (m) D
Toner specific gravity P
The external additive n particle size (m) d _n
External additive n specific gravity ρ _n
External additive input (g) W _n
Pi π
The toner particle size (m) is measured by “Coulter Multisizer III” manufactured by Coulter. The particle size (m) of the external additive is derived from an image projected by a transmission electron microscope (TEM) through an image processing apparatus. The specific gravity is measured with a “multi-pynometer” manufactured by Yuasa Ionics.

The one-component non-magnetic toner of the present invention has a circularity of 0.95 to 0.97, a flow softening temperature (Tf1 / 2) of 100 ° C. to 120 ° C., and a glass transition temperature (Tg) of 40 ° C. It is in the range of -50 ° C. The circularity is measured using a flow type particle image analyzer FPIA-1000 manufactured by Toa Medical Electronics Co., Ltd. Further, the flow softening temperature (Tf1 / 2) is 6 mm / min with a nozzle diameter of 1.0 mmΦ × 1.0 mm, a load per unit area (cm ² ) of 6 mm / min using a Shimadzu flow tester (CFT-500). It is a value measured at a heating rate of ° C. Furthermore, the glass transition temperature (Tg) is a value measured at a rate of temperature increase of 10 ° C. per minute by a second run method using a differential scanning calorimeter (DSC-50) manufactured by Shimadzu Corporation.

Next, the color image forming apparatus of the present invention will be described.
FIG. 1 is a diagram for explaining an outline of a color image forming apparatus of the present invention. In FIG. 1, a printer 10 includes a charging unit 30, an exposure unit 40, and a developing device holding unit along the rotation direction of a photoconductor 20. 50, a primary transfer unit 60, an intermediate transfer member 70, a cleaning unit 75, and a secondary transfer unit 80, a fixing unit 90, and the like.

  The photoreceptor 20 has a cylindrical conductive substrate and a photosensitive layer formed on the outer peripheral surface thereof, is rotatable around a central axis, and rotates clockwise as indicated by an arrow. The charging unit 30 is a device for charging the photoconductor 20, and the exposure unit 40 is a device for forming a latent image on the photoconductor 20 charged by irradiating a laser. The exposure unit 40 irradiates the charged photoconductor 20 with a modulated laser beam based on the image signal. Then, the laser beam is turned on / off at a predetermined timing, and a dot-like latent image is formed in a grid-divided area on the photoreceptor 20 that rotates at a predetermined speed.

  The developing device holding unit 50 converts the latent image formed on the photoreceptor 20 into black (K) toner contained in the black developing device 51, magenta (M) toner contained in the magenta developing device 52, and cyan developing device. This is an apparatus for developing using cyan (C) toner accommodated in 53 and yellow (Y) toner accommodated in the yellow developing device 54. The developing device holding unit 50 can move the positions of the four developing devices 51, 52, 53, and 54 by rotating. Each time the photosensitive member 20 rotates once, one of the four developing devices 51, 52, 53, 54 is selectively opposed to the photosensitive member 20, and the opposed developing devices 51, 52, 53, 54, The latent images formed on the photoconductor 20 are sequentially developed with the toner accommodated in 54.

  The primary transfer unit 60 is a device for transferring a single color toner image formed on the photoconductor 20 to the intermediate transfer body 70. When four color toners are sequentially transferred in a superimposed manner, the full color toner is transferred to the intermediate transfer body 70. An image is formed. The intermediate transfer member 70 is an endless belt, and is driven to rotate at substantially the same peripheral speed as the photosensitive member 20. The secondary transfer unit 80 is a device for transferring a single color toner image or a full color toner image formed on the intermediate transfer body 70 to a recording medium such as paper, film, or cloth.

  The fixing unit 90 is a device for fusing a single color toner image or a full color toner image transferred onto a recording medium onto a recording medium such as paper to form a permanent image. The cleaning unit 75 is provided between the primary transfer unit 60 and the charging unit 30 and has a rubber cleaning blade 76 that is in contact with the surface of the photoconductor 20. The cleaning unit 75 is disposed on the intermediate transfer body 70 by the primary transfer unit 60. After the toner image is transferred, the toner T remaining on the photoconductor 20 is scraped off and removed by the cleaning blade 76.

  Next, FIG. 2 is a diagram for explaining the developing device as a representative of the yellow developing device, and is a cross-sectional view showing the main components of the developing device. The developing device 54 includes a housing 540 that accommodates toner T, a developing roller 510, a toner supply roller 550 for supplying toner to the developing roller 510, and a layer thickness for regulating the layer thickness of the toner carried on the developing roller 510. There are a regulating blade 560, an upper seal 520 for sealing the upper gap between the housing 540 and the developing roller 510, an end seal 527 for sealing the gap on the end side between the housing 540 and the developing roller 510, and the like. is doing.

  A toner container 530 is formed inside the housing 540. The toner container 530 is divided into a first toner container 530a and a second toner container 530b by a partition wall 545. When the developing device holding unit 50 rotates, the toner stored in the first toner storage portion 530a and the second toner storage portion 530b is once collected on the upper communicating side of the developing position. When returning to the state shown in FIG. 2, the toners are mixed and returned to the first toner storage portion 530a and the second toner storage portion 530b. That is, the toner T in the developing device is agitated by the rotation of the developing device holding unit 50. For this reason, the toner storage unit 530 is not provided with a stirring member, but a stirring member for stirring the toner T stored in the toner storage unit 530 may be provided. As shown in FIG. 2, the housing 540 has an opening 572 in the lower portion, and a developing roller 510 described later is provided so as to face the opening 572.

  The roller portion of the toner supply roller 550 is formed of, for example, urethane foam having elasticity. The toner supply roller 550 is rotatably supported and is accommodated in the first toner accommodating portion 530a, supplies toner T to the developing roller 510, and excess toner remaining on the developing roller 510 after development. T is peeled off from the developing roller 510.

  The toner supply roller 550 and the developing roller 510 having a metal surface are assembled to the housing 540 while being pressed against each other. The roller portion of the toner supply roller is made of a foam member having an Asker F hardness of 70 °, and is in contact with the developing roller 510 in an elastically deformed state with a contact depth of 1.0 mm. The toner supply roller 550 is rotated in the direction opposite to the rotation direction of the developing roller 510 (counterclockwise in FIG. 2) (clockwise in FIG. 2), that is, the toner supply roller 550 is rotated with respect to the developing roller 510. Rotate.

  The colored particles obtained by the emulsion aggregation method or the phase inversion emulsion coalescence method are so-called “CCA-less toner” that does not contain a charge control agent or the like that affects the aggregation property in order to obtain a desired shape during production. It is often produced as. However, as a one-component non-magnetic toner, in order to have sufficient chargeability, it is necessary to be charged on the developing roller by a thin layer regulation by a regulating member, but it can be obtained by an emulsion aggregation method or a phase inversion emulsion coalescence method. The resulting colored particles are likely to be partially lost (partially missing aggregated particles) due to stress during thin layer regulation. For this reason, the wax component contained therein is exposed, causing filming of the developing roller 510, the regulating member 560, and the upper seal 520.

  Hydrophobic rutile-anatase type titanium oxide particles in the external additive of the present invention are more easily released from colored particles than hydrophobic monodisperse spherical large silica particles, but in combination with this hydrophobic rutile-anatase type titanium oxide particles Thus, it is considered that the hydrophobic monodispersed spherical large silica particles are easily added to the colored particles by subjecting the hydrophobic monodispersed spherical large silica particles to the colored particles. When printing with a large number of sheets, hydrophobic monodispersed spherical large silica particles move to the generated defects and are rearranged so as to fill the defects and cover the wax to prevent filming. It is considered to be done.

  The peripheral speed of the developing roller 510 is preferably 250 to 400 mm / s, and the larger the peripheral speed, the easier the rearrangement of the large silica. The peripheral speed of the toner supply roller 550 is preferably 400 to 600 mm / s, and the larger the toner speed, the more uniform the toner is in the developing chamber.

  It is the peripheral speed and the peripheral speed difference between the developing roller and the supply roller that promote the movement of the hydrophobic monodispersed spherical large silica particles on the surface of the colored particles. The peripheral speed difference (peripheral speed ratio) indicated by the supply roller peripheral speed / developing roller peripheral speed is preferably 1.4 to 1.7. The larger the peripheral speed ratio, the easier the rearrangement of the large silica, and at the same time, the resetting property (peeling / supplying) of the toner on the developing roller is enhanced and the replacement of the toner on the developing roller can be promoted.

  In the present invention, the developing roller 510 carries the toner T and conveys it to the developing position facing the photoconductor 20. The developing roller 510 is made of metal and is made of an aluminum alloy such as 5056 aluminum alloy or 6063 aluminum alloy, or an iron alloy such as STKM, and is subjected to nickel plating, chrome plating, or the like as necessary. May be. The surface of the developing roller 510 has a surface roughness (Rz) of 5 to 8 μm by a roughening process by sandblasting.

  Further, the developing roller 510 is rotatable about the central axis, and rotates in a direction (counterclockwise in FIG. 2) opposite to the rotation direction of the photoconductor 20 (clockwise in FIG. 2). As shown in FIG. 2, the developing device 54 develops the latent image formed on the photoconductor 20 in a non-contact state.

  The regulating blade 560 applies a charge to the toner T carried on the developing roller 510 and regulates the layer thickness of the toner T carried on the developing roller 510. The regulation blade 560 has a rubber part 560a and a rubber support part 560b. The rubber part 560a is made of silicon rubber, urethane rubber or the like, and the rubber support part 560b is a thin plate having spring properties such as phosphor bronze or stainless steel. The rubber part 560a is supported along one longitudinal side of the rubber support part 560b along the longitudinal direction of the rubber support part 560b, and the other end side of the rubber support part 560b is supported by the blade support metal plate 562. In this state, it is attached to the housing 540 via the blade support sheet metal 562. Further, a blade back member 570 made of malt plane or the like is provided on the side opposite to the developing roller 510 side of the regulating blade 560.

  Here, the rubber portion 560 a is pressed from the central portion of the developing roller 510 to both ends by the elastic force due to the bending of the rubber support portion 560 b. Further, the blade back member 570 prevents the toner T from entering between the rubber support portion 560b and the housing 540, stabilizes the elastic force due to the bending of the rubber support portion 560b, and provides rubber from the back of the rubber portion 560a. The rubber portion 560 a is pressed against the developing roller 510 by urging the portion 560 a toward the developing roller 510. Therefore, the blade back member 570 improves the uniform contact property of the rubber portion 560a to the developing roller 510.

  The end of the regulating blade 560 opposite to the side supported by the blade support metal plate 562, that is, the tip is not in contact with the developing roller 510, and a portion away from the tip by a predetermined distance is the developing roller. 510 is in contact with a width. In other words, the regulating blade 560 is not in contact with the developing roller 510 at the edge, but is in contact with the antinode on the flat surface of the rubber portion 560a. The regulating blade 560 is disposed so that the tip thereof faces the upstream side in the rotation direction of the developing roller 510, and is in a so-called counter contact. The protruding amount of the regulating blade is 0.7 to 1.0 mm, and the thin layer is regulated so that the toner layer thickness is 1 to 2 layers, preferably 1 to 1.6 layers.

The thin layer is regulated so that the toner conveyance amount is 0.45 to 0.90 mg / cm ² , preferably 0.45 to 0.72 mg / cm ² . The toner conveyance amount and the toner layer thickness have a relationship represented by the following formula.

Toner transport amount = (volume ratio) x (toner volume average particle diameter) x (toner specific gravity) x (toner layer thickness)
In the formula, the toner transport amount is calculated by attaching the toner on the developing roller to the adhesive tape, the mass of the toner attached to the adhesive tape is measured with an electronic balance (tape transfer method), and the volume ratio is a face-centered cubic lattice. The volume ratio of the structure (0.74) is adopted. The toner volume average particle size is measured by a multisizer TAIII type manufactured by Coulter, and the toner specific gravity is measured by a multipynometer manufactured by Yuasa Ionics. As is apparent from this equation, the good range of the toner conveyance amount varies depending on the toner particle diameter, and the good toner conveyance amount range is premised on the case where the average particle diameter of the toner is 5.5 μm.

  The rubber support portion 560b is longer than the rubber portion 560a in the axial direction of the developing roller 510, and extends outward from both ends of the rubber portion 560a. An end seal 527 made of, for example, a nonwoven fabric having a thickness thicker than that of the rubber portion 560a is attached to the same surface as the rubber portion and 560a at the extended portion of the rubber support portion 560b. At this time, the end surface of the rubber portion 560 a in the axial direction is in contact with the side surface of the end seal 527.

  The end seal 527 is provided so as to come into contact with both end portions of the surface of the developing roller 510 where no groove portion is provided when the developing roller 510 is attached, and has a width extending from the end portion of the developing roller 510 to the outside. is doing. Further, the end seal 527 extends sufficiently longer than the tip of the rubber portion 560 a of the regulating blade 560. When the regulating blade 560 is attached to the housing 540, the end seal 527 is placed along a portion of the housing 540 formed so as to face the outer peripheral surface of the developing roller 510, and closes the gap between the housing 540 and the developing roller 510. .

  The upper seal 520 prevents the toner T in the developing device 54 from leaking outside, and collects the toner T on the developing roller 510 that has passed through the developing position into the developing device without being scraped off. The upper seal 520 is a seal made of a polyethylene film or the like. The upper seal 520 is supported by a seal support sheet metal 522 and is attached to the housing 540 via the seal support sheet metal 522. A seal urging member 524 made of malt plain or the like is provided on the opposite side of the upper seal 520 from the developing roller 510 side. The upper seal 520 is developed by the elastic force of the seal urging member 524. 510 is pressed.

  In the developing device 54 configured as described above, the toner supply roller 550 supplies the toner T accommodated in the toner accommodating portion 530 to the developing roller 510. As the developing roller 510 rotates, the toner T supplied to the developing roller 510 reaches the contact position of the regulation blade 560, and when passing through the contact position, an electric charge is applied and the layer thickness is regulated. The

The charged toner T on the developing roller 510 reaches a developing position facing the photoconductor 20 by further rotation of the developing roller 510, and a latent image formed on the photoconductor 20 under an alternating electric field at the developing position. For development. Further, the toner T on the developing roller 510 that has passed the developing position by the rotation of the developing roller 510 passes through the upper seal 520 and is collected in the developing unit without being scraped off by the upper seal 520. The toner T still remaining on the developing roller 510 is peeled off by the toner supply roller 550.
Hereinafter, the present invention will be described in more detail with reference to examples.

A method for producing colored particles will be described. Hereinafter, “part” means part by mass.
(Preparation of resin fine particle dispersion)
・ Styrene ... 370g
・ N-Butyl acrylate ... 30g
・ Acrylic acid ・ ・ ・ 8g
・ Dodecanethiol ・ ・ ・ 24g
・ Carbon tetrabromide ・ ・ ・ 4g
6 g of nonionic surfactant (Nonipol 400: manufactured by Sanyo Kasei Co., Ltd.) and 10 g of anionic surfactant (Neogen SC: manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) were ion-exchanged. The mixture was emulsified and dispersed in a flask dissolved in 550 g of water, and 50 g of ion-exchanged water having 4 g of ammonium persulfate dissolved therein was added thereto while slowly mixing for 10 minutes. After carrying out nitrogen substitution, the inside of the flask was stirred and heated in an oil bath until the contents reached 70 ° C., and emulsion polymerization was continued for 5 hours. As a result, a resin fine particle dispersion in which resin particles having an average particle diameter of 150 nm, Tg = 58 ° C., and weight average molecular weight Mw = 11500 was obtained. The solid content concentration of this dispersion was 40% by mass.

(Preparation of colorant dispersion)
-Cyan pigment B15: 3 ... 60 g
・ Nonionic surfactant (Nonipol 400: Sanyo Kasei Co., Ltd.) ・ ・ 5g
・ Ion exchange water: 240g
The above components are mixed and dissolved, stirred for 10 minutes using a homogenizer (Ultra Turrax T50: manufactured by IKA), then dispersed with an optimizer, and a colorant (cyan pigment) having an average particle size of 250 nm. ) A colorant dispersion with dispersed particles was prepared.

(Preparation of release agent dispersion)
・ Polyethylene wax (PW725: Toyo Petrolite Co., Ltd.) ・ 100g
・ Ionic surfactant (Neogen RK: Daiichi Kogyo Seiyaku Co., Ltd.) ・ ・ 5g
・ Ion-exchanged water ... 200g
The solution in which the above components are mixed is heated to 95 ° C. and sufficiently dispersed with a homogenizer (Ultra Turrax T50: manufactured by IKA), and then dispersed with a pressure discharge homogenizer, and the average particle size is 210 nm. A release agent dispersion liquid in which release agent particles are dispersed was prepared.

(Preparation of colored particles)
-Resin fine particle dispersion prepared above-234 parts-Colorant dispersion prepared above-30 parts-Release agent dispersion prepared above-40 parts-Polyaluminum chloride (Asada Chemical) "PAC100W") ・ ・ 1.8 parts ・ Ion-exchanged water ・ ・ 600 parts The above ingredients were mixed and dispersed in a round stainless steel flask using a homogenizer (Ultra Turrax T50: manufactured by IKA). After that, the flask was heated to 50 ° C. with stirring in an oil bath for heating. After maintaining at 50 ° C. for 30 minutes, it was confirmed that aggregated particles having a D ₅₀ (volume average particle diameter) of 4.5 μm were formed. Further, the temperature of the heating oil bath was raised and maintained at 56 ° C. for 1 hour, and D ₅₀ (volume average particle diameter) was 5.3 μm.

Thereafter, 26 parts of the resin fine particle dispersion was added to the dispersion containing the aggregate particles, and then the temperature of the heating oil bath was raised to 50 ° C. and held for 30 minutes. After adding 1N sodium hydroxide to the dispersion containing the aggregated particles and adjusting the pH of the system to 5.0, the stainless steel flask was sealed and heated to 95 ° C. while continuing to stir for 4 hours. Retained and encapsulated. After cooling, the colored particles (toner base particles) were filtered off, washed four times with ion exchange water, and then freeze-dried to obtain toner base particles. The toner base particles had a D ₅₀ (volume average particle diameter) of 5.5 μm.

(Preparation of cyan toner)
After 100 parts of the colored particles (toner base particles) obtained above were put into a Henschel mixer (20 L), 1 part of hydrophobic rutile-anatase type titanium oxide particles (“STT30S” manufactured by Titanium Industry Co., Ltd., isobutyltrimethoxysilane treated product) And 1 part of hydrophobic monodispersed spherical large silica particles (“KEP10S2” manufactured by Nippon Shokubai Co., Ltd., primary particle size 100 nm, silicon oil treated product) were added and treated at a peripheral speed of 40 m / s for 2 minutes.

  After the treatment, 1.5 parts of hydrophobic small silica particles (“RX200” manufactured by Nippon Aerosil Co., Ltd., primary particle size: 12 nm, hexamethylsilazane-treated product) were additionally added and treated at a peripheral speed of 40 m / s for 2 minutes. Next, coarse particles were removed using a metal mesh having a mesh opening of 63 μm to obtain the toner of the present invention. The total coverage of the external additive particles in the toner is 152%.

(Image formation)
The obtained cyan toner was mounted on the image forming apparatus (LP9000C, manufactured by Seiko Epson Corporation) shown in FIG. The developing roller was formed to have a surface roughness of Rz = 7 μm, which was obtained by subjecting the surface of an iron hollow shell having an outer diameter of φ18 to sand-blasting and then Ni-P plating. The protruding amount of the restricting member was 0.76 mm. The supply roller was made of urethane sponge having an outer diameter of φ19 and Asker F hardness of 70 °, and was pressed against the developing roller at a contact depth of 1.0 mm. Further, the process speed is 210 mm / s, the developing roller peripheral speed is 336 mm / s, the supply roller peripheral speed is 504 mm / s, and the peripheral speed difference (peripheral speed ratio) indicated by the supply roller peripheral speed / developing roller peripheral speed is ) Was 1.5. Further, a color image was formed by an AC jumping development method under the conditions of a development gap of 150 μm with respect to the photoconductor, a direct current bias of −150 v, an alternating current bias of 1500 kHz (pp), and a duty of 60%. The bias potential set value of each process unit is a fixed bias potential set as default, and the toner amount adjustment patch sensor is not operated. Moreover, the test environment was 22-24 degreeC / 45-55% RH.

A toner evaluation method will be described.
(1) As an initial stage check, the developing device (developing cartridge) was rotated for 6 minutes by a single-drive test bench with rotary rotation.
(2) Next, the level of the state of the regulation blade passing leakage and the upper seal scattering was determined, and a predetermined check print pattern (full-color solid, full-surface half, history pattern, etc.) was output.
(3) Next, the transport amount on the developing roller, the charge amount on the developing roller, and the fog amount on the photoreceptor (OPC) were monitored.

a) The toner conveyance amount on the developing roller is 0.51 mg / cm ² as measured by the tape transfer method.
b) The charge amount by the toner suction method on the developing roller is -37.7 μC / g as measured using a “digital electrometer” manufactured by Advantest Corporation.
c) The amount of fog on the photoconductor (OPC) is such that the image forming process is forcibly stopped halfway during white solid pattern printing, and the fog toner remaining on the OPC is transferred and collected with a Scotch mending tape. After the transfer and recovery of the tape is affixed to the J paper, the change in the tape density is measured with a Macbeth densitometer. The OD value of the tape alone is 0.1 to 0.11, and the density increase exceeding this value corresponds to the fog toner amount.
(4) After the check in the initial stage is completed, the developing device (developing cartridge) is mounted on the image forming apparatus, and the durability test is started.
(5) In the durability test, an entire white solid pattern is continuously printed in 3000 sheets of A4 size paper in monochrome mode.
(6) After 3000 sheets are continuously printed, an intermediate check is performed. The check at the intermediate stage is the same procedure as the check at the initial stage.
(7) After the intermediate stage check is completed, the developing device (developing cartridge) is mounted on the image forming apparatus and the durability test is started.
(8) In the durability test, continuous printing is performed with 3000 sheets in total and 6000 sheets in total.
(9) After completion of continuous printing for a total of 6000 sheets, a check at the end of durability is performed. The check at the end of durability is the same procedure as the check at the initial stage.

  In the present invention, in the evaluation method described above, the determination method described below (3 persons to be determined) for each item of striped stripe unevenness, minute pitch unevenness, upper seal filming, and developing roller filming after the endurance of 6000 sheets The toner of the present invention was evaluated.

(Striped stripes)
This is an item indicating the uniformity of the toner layer restricted on the developing roller in the longitudinal direction of the developing roller, and the entire solid pattern (entire solid image) output on the A3 size J paper was visually determined. The number of striped stripes generated in the paper feeding direction (exposure sub-scanning direction) and the magnitude of density fluctuation were determined in comparison with the image sample for determination. The effect of the toner aggregation layer accumulated around the nip of the regulating blade in contact with the developing roller is received when regulating the thin layer of toner, resulting in a local decrease in the transport amount or a simultaneous increase in the charge amount. In this case, striped stripes having a reduced density are generated in a band shape (width of several mm or more). Conversely, the concentration may increase.

  The judgment criteria are as follows. In the following criteria, 3 or more was allowed, and for example, 3.5 was determined to be intermediate between the third and fourth stages. It should be noted that the determination was made by excluding the uneven noise caused by the ridge line accuracy of the regulation blade.

4: When striped streaks due to the accumulated toner aggregate layer at the time of toner thin layer formation cannot be seen at all 3: The density fluctuates in a strip shape with respect to the solid average OD concentration, and the increase or decrease in OD value is 0.1 or less A state in which several stripes are visually recognized by the visual judgment 2: A state in which the density variation in a strip shape with respect to the solid average OD concentration and a large number of stripes in which the increase or decrease in the OD value exceeds 0.1 are recognized by the visual judgment. In this state, a large number of striped stripes with the paper base exposed are recognized by visual judgment.

(Micro pitch unevenness)
This is an item indicating the uniformity of the toner layer restricted on the developing roller in the longitudinal direction of the developing roller, and the entire solid pattern (entire solid image) output on the A3 size J paper was visually determined. The number of fine stripes with a small width generated in the paper feed direction (exposure sub-scanning direction) and the magnitude of density fluctuation were determined by comparing them with the image sample for determination. When the toner thin layer is formed, the control blade or upper seal nip in contact with the developing roller and the toner lump (several millimeters or less) adhered to the periphery of the nip are affected. A small width (stripes of a width of several millimeters or less is generated. The determination criteria are as follows. The following determination criteria allow 3 or more.

4: A state in which there is no unevenness of a minute width in which the density fluctuates in a minute pitch due to a fixed toner lump at the time of forming a toner thin layer 3: An unevenness of the minute width does not cause density blurring, and the leading edge of the image or the trailing edge of the image 2: State where minute width unevenness has occurred over almost the entire length in the paper feed direction without density blurring 1: Minute pitch unevenness where the background of the paper is exposed due to density blurring has occurred across the entire image State.

(Upper seal filming)
As a result of the influence of the upper seal nip that contacts the developing roller and the toner mass (a few millimeters or less) fixed to the periphery of the nip, it is an irreversible that does not recover due to a peaky conveyance amount fluctuation on the toner conveyance surface regulated by a thin layer. Phenomenon that streaks occur. Determine the toner adhering to the surface of the upper seal or a part of the toner with a sample for judgment in five stages using a magnifier. The judgment criteria are as follows. 3 or more is acceptable according to the following criteria.

5: When there is no sticking in the contact nip of the upper seal and the vicinity thereof 4: Glossiness changes in the contact nip and the vicinity thereof, and a thin non-relief sticking occurs in a part of the vicinity of the nip 3 : Adhesion with minute undulations in the contact nip and the vicinity thereof, and the adhesion occurs in a part of the vicinity of the nip 2: Adhesion with undulations in the vicinity of the contact nip and the adhesion State in which merging occurs due to connection in the nip width direction 1: State in which the contact nip and its vicinity are undulated and the adhering is connected in the nip longitudinal direction.

(Developing roller filming)
As a result of the influence of the regulating blade abutting on the developing roller or the nip of the upper seal and the toner lump (a few mm or less) adhering to the periphery, recovery occurs due to a peaky conveyance amount fluctuation on the toner conveying surface where the thin layer is regulated. Phenomenon that irreversible streaks occur. Judgment is made in five stages by comparing the state of toner adhering to the surface of the developing roller or a part thereof (colored filming) with a sample for determination. The judgment criteria are as follows. 3 or more is acceptable according to the following criteria.

5: No state of toner fixing streaks on the developing roller (no deterioration in gloss due to thinned and fixed wax, etc.)
4: No toner sticking streaks on the developing roller (gloss deterioration due to thinned and stuck wax, etc. is acceptable)
3: There is no toner-fixed streak on the developing roller, but a reversible state in which minute pitch unevenness is repeatedly generated and disappeared on the image. 2: A fine pitch unevenness in which the toner-fixed streaks can be observed with a magnifying glass. 1: A state in which toner is fixed on the developing roller and colored streaks can be visually observed, and minute pitch unevenness that does not disappear always occurs.

  The results are shown in Table 1.

  FIG. 3 is a photograph of the particle structure of the toner in the initial stage taken with a scanning electron microscope (10,000 magnifications), and FIGS. 4 and 5 show the scanning of the particle structure of the toner after the endurance of 6000 sheets. It is the photograph image | photographed with the scanning electron microscope (10,000 times). In the toner at the initial stage, it can be seen from FIG. 3 that the hydrophobic monodispersed spherical large silica particles are uniformly attached to the surface of the colored particles (toner base particles). Further, after the endurance, the cracked surface (arrow portion) of the colored particles (toner base particles) can be confirmed from FIGS. 4 and 5, and the hydrophobic monodispersed spherical large silica particles are rearranged on the cracked surface. Is visible.

(Example 2)
The same procedure was performed except that 1 part of hydrophobic monodispersed spherical large silica particles (“KEP10S2” primary particle size 100 nm, silicon oil-treated product manufactured by Nippon Shokubai Co., Ltd.) was changed to 0.75 parts when preparing the cyan toner of Example 1. Thus, a cyan toner was prepared. The total coverage of the externally added particles in the toner is 150%. Further, image formation was carried out in the same manner as in Example 1, and the same evaluation was performed. The results are shown in Table 1.

(Example 3)
The same procedure was carried out except that 1 part of hydrophobic monodispersed spherical large silica particles (“KEP10S2” primary particle size 100 nm, silicon oil-treated product manufactured by Nippon Shokubai Co., Ltd.) was changed to 1.5 parts when preparing the cyan toner of Example 1. Thus, a cyan toner was prepared. The total coverage of the externally added particles in the toner is 157%. Further, image formation was carried out in the same manner as in Example 1, and the same evaluation was performed. The results are shown in Table 1.

  Example 4 In preparing the cyan toner of Example 1, 1 part of hydrophobic monodispersed spherical large silica particles (“KEP10S2” manufactured by Nippon Shokubai Co., Ltd., primary particle size 100 nm, silicon oil treated product) was changed to 0.5 part. A cyan toner was prepared in the same manner as described above. The total coverage of the externally added particles in the toner is 147%. Further, image formation was carried out in the same manner as in Example 1, and the same evaluation was performed. The results are shown in Table 1. Although striped stripes were visible, it was an acceptable limit.

  (Example 5) In preparing the cyan toner of Example 1, 1 part of hydrophobic monodispersed spherical large silica particles (“KEP10S2” manufactured by Nippon Shokubai Co., Ltd., primary particle size 100 nm, silicon oil-treated product) was changed to 2 parts. In the same manner, a cyan toner was prepared. The total coverage of the externally added particles in the toner is 162%. Further, image formation was carried out in the same manner as in Example 1, and the same evaluation was performed. The results are shown in Table 1. Although striped stripes were visible, it was an acceptable limit.

  (Example 6) In preparing the cyan toner of Example 1, three kinds of hydrophobic monodispersed spherical large silica particles, hydrophobic rutile-anatase type titanium oxide particles, and hydrophobic small silica particles were simultaneously added during the external addition treatment. A cyan toner was prepared in the same manner except for the above. The total coverage of the external additive particles in the toner is 152%. Further, image formation was carried out in the same manner as in Example 1, and the same evaluation was performed. The results are shown in Table 1. Although the upper seal filming was good, in addition to the evaluation in Table 1, there was a regulation leakage after being left for a long time as compared with Example 1.

  Example 7 In preparing the cyan toner of Example 1, hydrophobic monodispersed spherical large silica particles and hydrophobic small silica particles were added simultaneously as the first stage in the external addition process, and then hydrophobic rutile as the second stage. A cyan toner was prepared in the same manner except that anatase-type titanium oxide particles were added. The total coverage of the external additive particles in the toner is 152%. Further, image formation was carried out in the same manner as in Example 1, and the same evaluation was performed. The results are shown in Table 1. Although the top seal filming was good, the fog amount increased as compared with Example 1 in addition to the evaluation in Table 1.

  (Comparative Example 1) In preparing the cyan toner of Example 1, the same procedure was performed except that hydrophobic monodispersed spherical large silica particles (“KEP10S2” primary particle size 100 nm, silicon oil-treated product manufactured by Nippon Shokubai Co., Ltd.) were not added. A cyan toner was prepared. The total coverage of the external additive particles in the toner is 142%. Further, image formation was performed in the same manner as in Example 1.

  However, due to the increase in the toner layer thickness which does not occur in the toner of the present invention, the upper seal scattering, the increase in the amount of fog of the photosensitive member occurred, and the evaluation was stopped when the durability number was 3000 sheets. The regulation leakage is a phenomenon in which part of the toner leaks without being held by the developing roller when the toner layer passes through the regulating blade when the developing roller in the developing cartridge rotates. Further, the upper seal scattering is a phenomenon in which a part of the toner is scattered without being held by the developing roller when the toner layer passes through the upper seal when the developing roller of the developing cartridge is rotated. Further, the amount of photosensitive member fog is forcibly stopped during the white solid pattern printing, and the fog toner remaining on the OPC is transferred and collected with a Scotch mending tape. After the transfer and recovery of the tape is affixed to the J paper, the change in the tape density is measured with a Macbeth densitometer. The OD value of the tape alone is 0.1 to 0.11, and the density increase exceeding the OD value corresponds to the fog toner amount.

  (Comparative Example 2) In preparing the cyan toner of Example 1, instead of the hydrophobic rutile-anatase type titanium oxide particles, rutile type titanium oxide particles (“ST-485SA15” primary particle size 40-70 nm, manufactured by Titanium Industry Co., Ltd., stearin) A cyan toner was prepared in the same manner except that the acid-treated product was added. The total coverage of the externally added particles in the toner is 138%. Further, image formation was carried out in the same manner as in Example 1, and the same evaluation was performed. The results are shown in Table 1. The evaluation in Table 1 was the same as that of the example of the present invention. However, as in Comparative Example 1, there was a problem in the amount of seal scattering and fogging that did not occur in the toner of the present invention.

FIG. 1 is a diagram for explaining an outline of a color image forming apparatus of the present invention. FIG. 2 is a diagram for explaining the main components of the developing device. FIG. 3 is a photograph of the toner particle structure in the initial stage using the cyan toner prepared in Example 1 of the present invention, taken with a scanning electron microscope (10,000 times). FIG. 4 is a photograph of the toner particle structure after the endurance of 6000 sheets, taken with a scanning electron microscope (10,000 times) using the cyan toner prepared in Example 1 of the present invention. FIG. 5 is another example of a photograph in which the cyan toner prepared in Example 1 of the present invention was used and the toner particle structure after 6000 sheets of durability was photographed with a scanning electron microscope (10,000 times).

Explanation of symbols

  10 is a printer, 20 is a photoreceptor, 30 is a charging unit, 40 is an exposure unit, 50 is a developing device holding unit, 60 is a primary transfer unit, 70 is an intermediate transfer body, 75 is a cleaning unit, 80 is a secondary transfer unit, Reference numeral 90 is a fixing unit, 510 is a developing roller, 520 is an upper seal, 530 is a toner container, 540 is a housing, 550 is a toner supply roller, 560 is a regulating blade, and T is toner.

Claims (6)

It consists of colored particles containing at least a binder resin, a colorant and a release agent, and an external additive. As the external additive, the rutile type (10%), anatase type (90) with respect to 100 parts by mass of the colored particles. %), 0.5 to 2.0 parts by mass of spherical to spindle-shaped hydrophobic rutile-anatase type titanium oxide particles having a major axis diameter of 20 to 50 nm, and a hydrophobic monodisperse spherical large silica having a number average primary particle size of 100 nm One component non-magnetic toner characterized in that 0.5 to 2.0 parts by mass of particles and hydrophobic small silica particles having a number average primary particle size of 12 nm are added in an amount of 0.5 to 3.0 parts by mass. .
The particle size of the external additive is derived from an image projected by a transmission electron microscope (TEM) through an image processing apparatus. The external additive is added after the hydrophobic rutile-anatase-type titanium oxide particles and the hydrophobic monodispersed spherical large silica particles are externally added to the colored particles and then externally treated with the hydrophobic small silica particles. The one-component nonmagnetic toner according to claim 1. The colored particles are obtained by an emulsion aggregation method or a phase inversion emulsion coalescence method, have a volume average particle diameter (D ₅₀ ) of 4.0 to 7.0 μm, and contain 3 to 10% by mass of a release agent. The one-component non-magnetic toner according to claim 1 or 2. The one-component non-magnetic toner according to any one of claims 1 to 3, wherein the hydrophobic monodispersed spherical large silica particles are subjected to a hydrophobic treatment with silicone oil. At least a binder resin, a colorant, and a release agent for a photosensitive member carrying an electrostatic latent image and an electrostatic latent image that is arranged in a non-contact state with the photosensitive member and is carried on the photosensitive member. The external additive has a rutile type (10%), anatase type (90%), and a major axis diameter of 20 to 50 nm with respect to 100 parts by mass of the colored particles . 0.5 to 2.0 parts by mass of spherical to spindle-shaped hydrophobic rutile-anatase type titanium oxide particles and 0.5 to 2.0 parts by mass of hydrophobic monodisperse spherical large silica particles having a number average primary particle size of 100 nm A developing roller having a metal surface for carrying and developing a one-component non-magnetic toner having an addition ratio of 0.5 to 3.0 parts by mass of hydrophobic small silica particles having a number primary average particle size of 12 nm , It is disposed in pressure-contact with the developing roller and rotates with the toner. The peripheral speed of the supply roller is set to 400 to 600 mm / s, and the peripheral speed ratio indicated by the supply roller peripheral speed / developing roller peripheral speed is set to 1.3 to 1. An image forming apparatus comprising: a developing device;
The particle size of the external additive is derived from an image projected by a transmission electron microscope (TEM) through an image processing apparatus. 6. The image forming apparatus according to claim 5, wherein the one-component nonmagnetic toner is regulated to have a thin layer thickness of 1 to 2 on the developing roller.