JP2008070719A - Toner for electrostatic latent image development, image forming apparatus and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner for electrostatic latent image development that can suppress generation of scratches on an image holding body, and to provide an image forming apparatus that can achieve both of suppressing scratches on an image holding body and toner cleaning property. <P>SOLUTION: The toner for electrostatic latent image development comprises first inorganic particles having a number average particle diameter of 30 nm or less and having a free surface treating agent by 2 to 50 mass%, and second inorganic particles having a number average particle diameter of 80 to 200 nm. The image forming apparatus is characterized in that: the above toner is used as a toner, the toner has an average shape factor SF1 of 110 to 125; and the pushing pressure of a cleaning blade to an image holding body is 3.9×10<SP>-2</SP>to 6.9×10<SP>-2</SP>mN/cm. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrostatic latent image developing toner used for developing an electrostatic latent image in electrophotography and electrostatic recording, an image forming apparatus using the same, and a process cartridge.

  Compared with the conventional toner produced by the pulverization method, the polymerized toner can be reduced in diameter and has a sharp particle size distribution and shape distribution, which is suitable for forming a high-quality image. However, there is also a problem that the toner is likely to pass through between the cleaning member such as the image holding member and the cleaning blade, and cleaning failure is likely to occur.

  On the other hand, in order to improve the cleaning property of the polymerized toner in the blade cleaning method, a proposal has been made to set the linear pressure of the cleaning blade higher than that of the pulverized toner. However, when the linear pressure of the cleaning blade with respect to the image carrier is increased, stress due to friction between the surface of the image carrier and the cleaning blade increases, and there is a problem that damage and abrasion of the blade increases. In addition, the stick-slip width of the cleaning blade increases as the rubbing stress increases, and there is a problem that toner slips through the gap between the cleaning blade and the image carrier (cleaning failure) when the state changes. .

In order to suppress this cleaning failure, it is necessary to reduce the torque between the cleaning blade and the pressing part of the image carrier and not to make the stick slip width too wide. To achieve this, a monodispersed large diameter Proposals using silica and the like have been made.
However, as the torque between the image carrier and the cleaning blade and the distortion of the cleaning blade become smaller, the contact area between the image carrier and the cleaning raid and the stick-slip behavior of the cleaning blade become smaller accordingly. If this is excessive, the concentration of stress that comes into contact with the image carrier at almost the same location near the blade edge becomes a problem. When the external additive and small-diameter toner component present in the pressing portion between the cleaning blade and the image carrier are subjected to the force and form adhesion and aggregation at the blade edge, the external additive acts as abrasive grains on the surface of the image carrier. The problem of scratching occurs. Further, when the image carrier flaw occurs, the pressing between the cleaning blade and the image carrier at that portion becomes insufficient, and toner slip occurs from there.
In particular, in a tandem image forming apparatus, for example, when a large amount of black and white images are continuously formed, toner and external additives are not newly supplied to the surface of the image carrier for color image formation. A specific external additive or small-diameter toner component is deposited near the contact portion between the cleaning blade and the image carrier and receives a pressing force from the blade (stress concentration), and adheres to the blade edge. The image carrier is easily damaged by the external additive.

  On the other hand, a method has been proposed in which the liberated amount of the external additive having a large particle size added to the toner is reduced (see, for example, Patent Document 1). However, since the amount of the free external additive per toner particle is small, more specific external additive is subjected to a pressure contact force at the pressing portion between the blade and the image carrier and easily forms adhesion aggregation. The image carrier is easily scratched by.

  In addition, ultrafine particles having a strong adhesion (volume average particle size 0.0025 to 0.05 μm is 0.5 to 1.0% by mass) and small particles having a strong cohesion (volume average particle size 0.5 to 1.0%) 2.0 μm is used as an external additive, and the flocculant layer is formed in the vicinity of the blade pressing portion, and the area where the pressure contact force is applied is less involved in image carrier scratches. A method has been proposed in which image carrier damage wear is suppressed by interposing fine particles, and is compatible with toner cleaning properties (see, for example, Patent Document 2). However, an effect can be expected when the amount of both external additives (the ultrafine particles and small particle size fine particles) supplied to the blade pressing portion is large. However, both external additives such as the surface of an image carrier for color image formation of a tandem method When the new supply is insufficient, the ultrafine particles are depleted, and the antiskid effect by the ultrafine particles is insufficient, and the small particle size particles tend to enter the blade pressing portion and generate image carrier scratches.

  Also, by using a large particle size external additive in combination with a large particle size reverse polarity charged powder, the cohesiveness of the large particle size external additive is inhibited, and image retention derived from the large particle size external additive is maintained. A method for reducing body scratches has been proposed (see, for example, Patent Document 3). However, in a small-sized image forming apparatus, it is preferable to supply the toner in an externally added form by an external supply unit because of space. However, since the reverse-polarized powder has a reverse polarity and is image-dependent, it is a non-image. On the other hand, since the large particle size external additive is easily supplied to the image portion in the same manner as the toner, there is still room for improvement in a small machine.

In other words, there has not yet been a method for achieving a high level of both good cleaning properties for toner and the like and suppression of scratches on the photoreceptor, and further improvements have been desired.
JP 2006-030654 A JP 2002-323836 A JP 2004-053717 A

An object of the present invention is to solve the above-described problems in the prior art.
That is, an object of the present invention is to develop an electrostatic latent image developing toner capable of suppressing generation of image carrier scratches, and an image forming apparatus capable of achieving both suppression of image carrier scratches and toner cleaning properties. And providing a process cartridge.

The object of the present invention is achieved by the following present invention.
That is, the electrostatic latent image developing toner of the present invention is
<1> A first inorganic particle having a number average particle diameter of 30 nm or less and a free surface treating agent amount of 2 to 50% by mass, and a second inorganic particle having a number average particle diameter of 80 to 200 nm are contained. An electrostatic latent image developing toner.
<2> The electrostatic latent image developing toner according to <1>, wherein the powder fluidity is 5 to 30%.

The image forming apparatus according to the present invention includes:
<3> An image carrier, an electrostatic latent image forming unit that forms a latent image on the image carrier, a developing unit that develops the latent image with toner to form a visible image, and the visible image At least a transfer unit that transfers to a recording medium and a cleaning unit that removes toner remaining on the image carrier after transfer using a cleaning blade. The toner is free with a number average particle size of 30 nm or less. While containing the 1st inorganic particle whose surface treating agent amount is 2-50 mass%, and the 2nd inorganic particle whose number average particle diameter is 80-200 nm, average shape factor SF1 is 110-125. And the pressing force of the cleaning blade against the image carrier is 3.9 × 10 ^{−2 to} 6.9 × 10 ⁻² mN / cm.

Furthermore, the process cartridge of the present invention includes:
<4> An image holding member that is detachable from a loading unit of the image forming apparatus, a developing device that forms a visible image by developing a latent image formed on the image holding member with toner, and an image holding A cleaning device that removes toner remaining on the body using a cleaning blade, wherein the toner has a number average particle size of 30 nm or less and a free surface treatment amount of 2 to 50% by mass. And the second inorganic particles having a number average particle size of 80 to 200 nm, the average shape factor SF1 is 110 to 125, and the pressing force of the cleaning blade against the image carrier is It is a process cartridge characterized by being 3.9 × 10 ^{−2 to} 6.9 × 10 ⁻² mN / cm.

  According to the present invention, an electrostatic latent image developing toner capable of suppressing occurrence of image carrier scratches, an image forming apparatus capable of achieving both suppression of image carrier scratches and toner cleaning properties, and A process cartridge can be provided.

[Electrostatic latent image developing toner]
The electrostatic latent image developing toner of the present invention (hereinafter sometimes simply referred to as “toner”) is a first inorganic material having a number average particle size of 30 nm or less and a free surface treating agent amount of 2 to 50% by mass. It contains particles (small-diameter external additive) and second inorganic particles (large-diameter external additive) having a number average particle diameter of 80 to 200 nm.

  Under compaction in the vicinity of the pressing part (nip) between the image carrier and the cleaning blade, the large-diameter external additive and the small-diameter external additive including the free surface treatment agent contact and adhere to each other so that the large-diameter external additive The rolling friction is increased, the rolling property of the large-diameter external additive is lowered, and the large-diameter external additive can be prevented from entering the pressing portion. Even when the cleaning blade is pressed, the free surface treatment agent adheres to the surface of the large-diameter external additive and the small-diameter external additive intervenes. It is difficult to occur, and adhesion and aggregation due to the large-diameter external additive at the blade edge portion is reduced. Therefore, by using the toner of the present invention, it is possible to achieve both suppression of image carrier scratches caused by the large-diameter external additive and toner cleaning properties.

Note that, in an image forming apparatus using a so-called spherical toner having an average shape factor SF1 of 110 to 125, the toner cleaning property is particularly problematic. Therefore, the cleaning performance is improved by setting the pressing pressure of the cleaning blade high. There is technology to secure. In order to obtain good toner cleaning properties, the pressing pressure is preferably 3.9 × 10 ^{−2 to} 6.9 × 10 ⁻² mN / cm, but in this case, naturally, the image holding by the large-diameter external additive is performed. Since body scratches become a problem, the effect of the toner of the present invention is remarkably exhibited.

  Further, in an image forming apparatus using a contact-type charging device or an apparatus capable of high-speed image formation, it is important to reduce the torque at the pressing portion between the image carrier and the cleaning blade. The torque can be reduced by the additive. Of course, in this case as well, the effect of improving the scratches on the image carrier by the toner of the present invention is remarkably exhibited.

Hereinafter, the components of the toner for developing an electrostatic latent image according to the present invention will be sequentially described.
(External additive)
In the toner of the present invention, as the external additive, first inorganic particles (small external additive) having at least a number average particle size of 30 nm or less and a free surface treating agent amount of 2 to 50% by mass, and a number average particle are used. 2nd inorganic particle (large-diameter external additive) whose diameter is 80-200 nm is contained.

-Second inorganic particles (external additive for large diameter)-
The large-diameter external additive used in the present invention has a number average particle diameter of 80 to 200 nm. When the number average particle size is larger than 200 nm, the penetration into the cleaning blade pressing portion is reduced, and the stick slip width is increased to cause blade wear and toner slip. On the other hand, if it is smaller than 80 nm, the penetration property to the blade pressing portion is further increased, and the effect of reducing the penetration / aggregation by the first inorganic particles (small-diameter external additive) is reduced.
The number average particle diameter of the large external additive is more preferably 100 to 150 nm, and particularly preferably 100 to 130 nm.

  A method for measuring the number average particle diameter of the external additives (the large-diameter external additive and the small-diameter external additive described later) will be described later.

As the large-diameter external additive, monodispersed spherical silica is preferably used particularly from the viewpoint of improving toner cleaning properties, improving transfer properties, and reducing torque. Since monodispersed spherical silica is monodispersed and spherical, it can be uniformly dispersed on the surface of the toner base particles, and a stable spacer effect can be obtained.
The definition of the monodispersion can be discussed in terms of the standard deviation with respect to the average particle diameter including aggregates, and the standard deviation is preferably number average particle diameter × 0.22 or less. In addition, the definition of the sphere in the present invention can be discussed in terms of Wadell's sphericity, and the sphericity is preferably 0.6 or more, and more preferably 0.8 or more.
The reason why silica is particularly preferable is that the refractive index is around 1.5, and even if the particle size is increased, the transparency is lowered due to light scattering, and particularly the haze value at the time of taking an image on OHP is affected. Not to mention.

  General fumed silica has a true specific gravity of 2.2, and the maximum particle size of 50 nm is a limit from the viewpoint of production. Moreover, although the particle size can be increased as an aggregate, uniform dispersion and a stable spacer effect cannot be obtained. On the other hand, other typical inorganic particles used as external additives include titanium oxide (true specific gravity 4.2, refractive index 2.6), alumina (true specific gravity 4.0, refractive index 1.8), oxidation Zinc (true specific gravity of 5.6, refractive index of 2.0) can be mentioned, but all of them have high true specific gravity, and when the particle size is 80 nm or more that effectively expresses the spacer effect, peeling from the toner base particles is likely to occur. The peeled particles are easily transferred to a charge imparting member, an image carrier, or the like, which causes charge reduction or image quality defects. Also, since the refractive index is high, it is not suitable for producing color images to use inorganic particles having a large particle size.

  The monodispersed spherical silica having a number average particle size of 80 to 200 nm in the present invention can be obtained by a sol-gel method which is a wet method. The particle size can be freely controlled by the hydrolysis of the sol-gel method, the mass ratio of alkoxysilane, ammonia, alcohol, water in the condensation polymerization step, the reaction temperature, the stirring rate, and the supply rate. Monodisperse and spherical shapes can also be achieved by making this technique.

  Specifically, tetramethoxysilane is dropped and stirred while applying temperature using ammonia water as a catalyst in the presence of water and alcohol. Next, the silica sol suspension obtained by the reaction is centrifuged to separate into wet silica gel, alcohol and aqueous ammonia. A solvent is added to wet silica gel to form a silica sol again, and a hydrophobizing agent is added to hydrophobize the silica surface. Next, the target monodispersed spherical silica can be obtained by removing the solvent from the hydrophobized silica sol, drying, and sieve. Further, the silica thus obtained may be treated again. Next, the silica external additive of the present invention can be obtained by removing the solvent from the hydrophobized silica sol and drying it.

Furthermore, a dry method such as a spray drying method in which a treatment agent or a solution containing a treatment agent is sprayed on particles suspended in a gas phase, or a wet method in which particles are immersed in a solution containing a treatment agent and dried. It can be processed by a method, a mixing method in which a processing agent and particles are mixed by a mixer. Further, after the surface treatment, a step of washing with a solvent and removing a residual treatment agent or a low-boiling residue may be added.
In addition, the manufacturing method of the monodispersed spherical silica in this invention is not limited to the said manufacturing method.

  As the hydrophobizing agent, a general coupling agent, silicone oil, fatty acid, fatty acid metal salt, or the like can be used, but it is preferable to perform surface treatment including a silane coupling agent from the viewpoint of production stability. .

The said silane compound can use a water-soluble thing.
As such a silane compound, chemical structural formula R _a SiX _4-a (wherein, a is an integer of 0 to 3, R represents an organic group such as a hydrogen atom, an alkyl group, and an alkenyl group; Represents a hydrolyzable group such as a chlorine atom, a methoxy group, and an ethoxy group.), And any type of chlorosilane, alkoxysilane, silazane, and a special silylating agent is used. It is also possible.
Specifically, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, tetramethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, tetraethoxysilane, Methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, isobutyltrimethoxysilane, decyltrimethoxysilane, hexamethyldisilazane, N, O- (bistrimethylsilyl) acetamide, N, N-bis (Trimethylsilyl) urea, tert-butyldimethylchlorosilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxy Silane, γ-methacryloxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-mercapto Representative examples include propyltrimethoxysilane and γ-chloropropyltrimethoxysilane.
Particularly preferably, the hydrophobizing agent in the present invention includes dimethyldimethoxysilane, hexamethyldisilazane, methyltrimethoxysilane, isobutyltrimethoxysilane, decyltrimethoxysilane and the like.

  Specific examples of silicone oils include, for example, organosiloxane oligomers; cyclic compounds such as octamethylcyclotetrasiloxane or decamethylcyclopentasiloxane, tetramethylcyclotetrasiloxane, tetravinyltetramethylcyclotetrasiloxane, linear or branched Can be mentioned. Further, a highly reactive silicone oil in which a modifying group is introduced into a side chain or one end or both ends, a side chain piece end, or both side chain ends may be used. Examples of the modifying group include alkoxy, carboxyl, carbinol, higher fatty acid modification, phenol, epoxy, methacryl, amino and the like, but are not particularly limited. Further, it may be a silicone oil having several kinds of modifying groups such as amino / alkoxy modification.

  Further, dimethyl silicone oil, these modified silicone oils, and other surface treatment agents may be mixed or used in combination (such as silane coupling agents (including HMDS), etc.). ). Examples of the treating agent used in combination include silane coupling agents, titanate coupling agents, aluminate coupling agents, various silicone oils, fatty acids, fatty acid metal salts, esterified products thereof, rosin acid, and the like. .

  The viscosity of the silicone oil is preferably 500 centistokes or less because it is easy to uniformly adhere to the surface of the external additive particles. More preferably, 300 centistokes or less is more suitable for use, and even more preferably 200 centistokes or less.

  The addition amount of the large-diameter external additive is preferably 0.5 to 5 parts by mass, more preferably 1 to 3 parts by mass with respect to 100 parts by mass of toner base particles described later. When the addition amount is less than 0.5 parts by mass, the effect of reducing non-electrostatic adhesion is small, and the effect of improving development and transfer may not be obtained sufficiently. On the other hand, the addition amount is more than 5 parts by mass. Then, the amount of the toner mother particle surface exceeding the amount that can be coated by one layer is exceeded, the coating becomes excessive, and the external additive is transferred to the contact member, which easily causes a secondary failure.

-First inorganic particles (small-diameter external additive)-
The small-diameter external additive used in the present invention has a number average particle diameter of 30 nm or less and a free surface treatment agent amount (that is, free carbon amount) of 2 to 50% by mass. When the amount of the free surface treatment agent is less than 2% by mass, the effect of suppressing aggregation of the large-diameter external additive is small, and the effect of suppressing scratches on the image carrier cannot be obtained. On the other hand, when it exceeds 50% by mass, the powder agglomeration property of the toner deteriorates, and the powder transportability, developability and transferability deteriorate. The amount of the free surface treatment agent is more preferably 20 to 45% by mass, and particularly preferably 35 to 45% by mass.
Further, the smaller the number average particle diameter, the more the contact area with the large-diameter external additive increases, so that the effect can be expected. However, if the thickness is less than 5 nm, the adhesion to the surface of the toner base particles is high, and the toner tends to be buried in the surface of the toner due to stress in the developing machine. The number average particle diameter is more preferably 20 nm or less, and particularly preferably 15 nm or less.

Here, a method for measuring the amount of the free surface treatment agent will be described.
2 g of toner is added to 40 ml of a 0.2% by mass surfactant (polyoxyethylene (10) octylphenyl ether having a polyoxyethylene polymerization degree of 10 manufactured by Wako Pure Chemical Industries, Ltd.), and the toner gets wet with the aqueous solution. Disperse sufficiently. In this state, an ultrasonic homogenizer US300T (manufactured by Nippon Seiki Seisakusho) is used, and an ultrasonic vibration with an output of 20 W and a frequency of 20 kHz is applied for 1 minute to desorb the additive particles. Thereafter, the toner is separated under conditions of 3000 rpm × 7 minutes through a 50 ml centrifuge with a sedimentation tube (compact cooling high-speed centrifuge Model M160 IV, manufactured by Sakuma Seisakusho Co., Ltd.), and the supernatant liquid is separated into a membrane filter (Nippon Millipore (Japan Millipore ( After suction filtration with FHLP02500), the filtrate is further suction filtered with a membrane filter having a pore size of 0.22 μm (GSEP047SO) and a pore size of 0.025 μm (VSWP02500), and the furnace liquid is dried. NMR measurement of the dried residue can be performed under specified conditions (described in detail later), and the amount of the free surface treatment agent can be converted from the peak of the free surface treatment agent. If the sample amount necessary for measurement cannot be collected at once, the same operation is repeated until the sample amount necessary for measurement can be collected.

The said small diameter external additive used for this invention can be manufactured by making a surface treatment agent react with a core material.
As a manufacturing method of the small-diameter external additive, a gas phase method, a wet manufacturing method including a sol-gel manufacturing method, or the like can be employed. Examples of the surface treatment method include a dry method such as a spray drying method in which a treatment agent or a solution containing a treatment agent is sprayed on particles suspended in a gas phase, or particles in a solution containing the treatment agent. Examples include a wet method of dipping and drying, and a mixing method of mixing the processing agent and particles with a mixer. In addition, a step of washing with a solvent after the surface treatment to remove the residual treatment agent or low-boiling residue may be added. In the present invention, the production method is not particularly limited.

  Examples of the material used for the core material include silica, titania, metatitanic acid, zinc oxide, zirconia, magnesia, calcium carbonate, magnesium carbonate, calcium phosphate, cerium oxide, and strontium titanate. Among them, silica is preferable. . Silica has higher liberty from the toner surface than titania and alumina, and the chance of contact with a large-diameter external additive increases, so that the effect of the present invention tends to be remarkable.

Examples of the surface treatment agent include general coupling agents, silicone oils, fatty acids, fatty acid metal salts, etc. Among them, silicone oils and long chain silane coupling agents (carbon number of alkyl chain such as decylsilane) Is preferably 10 or more). As the surface treating agent, the above materials may be used alone or a plurality of materials including the above materials may be used in combination.
The amount of the free surface treatment agent described above can be controlled by adjusting the amount of the surface treatment agent added.

  The addition amount of the small-diameter external additive obtained as described above in the toner is preferably 0.3 to 5% by mass, and preferably 0.3 to 1.5% by mass with respect to the toner described later. More preferably. By being within the above range, it is possible to satisfactorily achieve suppression of image carrier scratches, which is an effect of the present invention.

  The external additives (large-diameter external additive and small-diameter external additive) according to the present invention obtained as described above are added and mixed in the toner. As the mixing method, for example, a V-type blender, It can be performed by a known mixer such as a Henschel mixer or a Redige mixer.

-Other external additives-
Furthermore, various other additives may be added to the electrostatic latent image developing toner of the present invention as required. Examples of these additives include other fluidizing agents, cleaning aids such as polystyrene particles, polymethyl methacrylate particles, and polyvinylidene fluoride particles, or transfer aids.
When the external additives (including large-diameter external additives and small-diameter external additives) and other additives are externally added to the toner, they may be added and mixed at the same time, or added and mixed in stages. Also good. Moreover, it does not matter even if it goes through a sieving process after external addition mixing.

(Toner mother particles)
The toner base particles used in the present invention can be produced from materials such as a binder resin, a colorant, and a release agent, and a charge control agent and the like may be added as necessary.
-Binder resin-
Examples of the binder resin used in the present invention include styrenes such as styrene and chlorostyrene, monoolefins such as ethylene, propylene, butylene and isoprene, vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate and vinyl butyrate. , Α-methylene aliphatic monocarboxylic such as methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate Examples of homopolymers and copolymers of acid esters, vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, and vinyl butyl ether, and vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, and vinyl isopropenyl ketone Particularly typical binder resins include polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene. -Maleic anhydride copolymer, polyethylene, polypropylene and the like. Further examples include polyester, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, paraffin wax and the like.

-Colorant-
Examples of the colorant used in the present invention include magnetic powders such as magnetite and ferrite, carbon black, aniline blue, caryl blue, chrome yellow, ultramarine blue, dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, and malachite green. Oxalate, lamp black, rose bengal, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 57: 1, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 17, C.I. I. Pigment blue 15: 1, C.I. I. Pigment Blue 15: 3 can be exemplified as a representative one.

-Release agent-
Typical examples of the release agent used in the present invention include low molecular polyethylene, low molecular polypropylene, Fischer-Tropsch wax, montan wax, carnauba wax, rice wax, and candelilla wax.

-Charge control agent-
As the charge control agent to be added as necessary, known ones can be used, but an azo metal complex compound, a metal complex compound of salicylic acid, and a resin type charge control agent containing a polar group should be used. Can do.

(Manufacture of toner for developing electrostatic latent images)
The method for producing the toner of the present invention desirably satisfies the preferable average shape factor and preferred particle diameter range of the toner described later, but is not particularly limited by the production method, and a known method can be used. it can.
First, toner base particles containing a binder resin, a colorant, a release agent, and the like are prepared using the following method. For example, a binder resin, a colorant, a release agent, and a kneading and pulverizing method in which a charge control agent and the like are further kneaded, pulverized, and classified as necessary. Method of changing shape by thermal energy, emulsion polymerization of polymerizable monomer of binder resin, dispersion formed, dispersion of colorant, release agent, and charge control agent as required Are mixed, agglomerated, and heat-fused to obtain toner mother particles, an emulsion polymerization aggregation method, a polymerizable monomer, a colorant, and a release agent for obtaining a binder resin, and a charge control agent as required Suspension polymerization method in which solution such as suspension is polymerized by suspending in aqueous solvent, particle shape obtained by suspension polymerization method is changed by mechanical impact force or thermal energy, binder resin, coloring Suspension agent, release agent, and if necessary, charge control agent solution in aqueous solvent and granulate Solution suspension method can be used. In addition, a manufacturing method may be performed in which the toner obtained by the above method is used as a core, and agglomerated particles are further adhered and heat-fused to give a core-shell structure.
Further, the toner in the present invention may be either a magnetic toner containing a magnetic material or a non-magnetic toner containing no magnetic material.

  Next, external additives including the first inorganic particles (small-diameter external additive) and the second inorganic particles (large-diameter external additive) are externally added. As described above, the external additive is added by adding the external additive to the toner base particles obtained as described above, for example, using a known mixer such as a V-type blender, a Henschel mixer or a Redige mixer. The method of mixing is mentioned.

As the electrostatic latent image developing toner of the present invention, it is preferable to use a toner having an average shape factor SF1 in the range of 110 to 125 from the viewpoints of high development, transferability, and high-quality images.
The average shape factor SF1 is obtained by the following formula (1).
SF1 = (ML ² / A) × (π / 4) × 100 (1)
In Expression (1), ML represents the maximum toner length, A represents the projected area of the toner, and SF1 = 100 in the case of a true sphere. A specific method for obtaining the shape factor will be described later.

Further, the volume average particle diameter of the toner of the present invention is preferably 3 to 6 μm, more preferably 5 to 6 μm, from the viewpoint that high development, transferability, and high-quality images can be obtained.
A method for measuring the volume average particle diameter of the toner will be described later.

  A spherical toner having an average shape factor SF1 in the above range and a small particle size toner having a volume average particle size in the above range can expect a high-quality image as described above, but have a poor toner cleaning property and are normally cleaned. The pressure of the blade against the image carrier is set to a high value. For this reason, the generation of scratches on the image carrier becomes a problem. However, the use of the toner of the present invention makes it possible to obtain a particularly remarkable effect of suppressing the generation of scratches.

Further, the toner for developing an electrostatic latent image of the present invention obtained from the above preferably has good powder characteristics as the toner, preferably has a powder flowability of 5 to 30%, and 5 to 15 % Is more preferable. The powder flowability is in the above range, so that the replenishment from the toner cartridge to the developing machine, the mixing ability of the replenished toner and the developer is performed well, and the good developability, chargeability, and transfer that do not change with time. Sex can be maintained. Therefore, it is preferable in terms of achieving improvement in image carrier scratches and maintenance of cleaning properties without deteriorating other characteristics.
As a method for controlling the powder fluidity within the above range, a method using the above-mentioned monodispersed spherical silica as the second inorganic particles (large-diameter external additive) can be cited as a good control method.

[Developer for electrostatic latent image development]
The electrostatic latent image developing developer of the present invention (hereinafter sometimes simply referred to as “developer”) is a one-component developer composed of the toner, but two-component development in which the toner is added to a carrier. Any of the agents may be used.

(Carrier)
As the carrier used in the present invention, a resin-coated carrier having a resin coating layer in which a conductive material is dispersed and contained on a core material is preferably used. When spherical toner is used as the toner base particles, the packing property is inevitably increased at the conveyance restriction portion in the developing device, and accordingly, a strong force is applied not only to the toner surface but also to the carrier. Therefore, by including a conductive material dispersed in the resin coating layer of the carrier, even if the resin coating layer is peeled off, it is possible to maintain high image quality over the long term without greatly changing the volume specific resistance of the carrier. can do.

Examples of the core material of the carrier include magnetic metals such as iron, nickel, and cobalt, magnetic oxides such as ferrite and magnetite, and glass beads. However, in order to adjust the volume resistivity using the magnetic brush method, a magnetic material is used. Preferably there is.
The average particle diameter of the core material is generally 10 to 500 μm, preferably 30 to 100 μm.

  The matrix resin used for the resin coating layer is polyethylene, polypropylene, polystyrene, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer. , Styrene-acrylic acid copolymer, straight silicone resin composed of organosiloxane bond or modified product thereof, fluororesin, polyester, polyurethane, polycarbonate, phenol resin, amino resin, melamine resin, benzoguanamine resin, urea resin, amide resin, epoxy Although resin etc. can be illustrated, it is not limited to these.

Examples of the conductive material include metals such as gold, silver, and copper, and titanium oxide, zinc oxide, barium sulfate, aluminum borate, potassium titanate, tin oxide, and carbon black, but are not limited thereto. It is not a thing.
The content of the conductive material is preferably 1 to 50 parts by mass and more preferably 3 to 20 parts by mass with respect to 100 parts by mass of the matrix resin.

  As a method for forming a resin coating layer on the surface of the carrier core material, a dipping method in which the carrier core material is immersed in a coating layer forming solution containing a matrix resin, a conductive material and a solvent, or a coating layer forming solution is used as the carrier. Spray method for spraying on the surface of the core material, fluidized bed method for spraying the coating layer forming solution in a state where the carrier core material is floated by flowing air, mixing the carrier core material and the coating layer forming solution in a kneader coater, The kneader coater method etc. which remove a solvent are mentioned.

  The solvent used in the coating layer forming solution is not particularly limited as long as it dissolves the matrix resin. For example, aromatic hydrocarbons such as toluene and xylene, and ketones such as acetone and methyl ethyl ketone. , Ethers such as tetrahydrofuran and dioxane can be used.

  The average film thickness of the resin coating layer is usually 0.1 to 10 μm, but in the present invention, it is preferably in the range of 0.5 to 3 μm in order to develop a stable volume resistivity of the carrier over time. .

The volume resistivity of the carrier produced as described above is 10 ⁶ to 10 ¹⁴ in the range of 10 ³ to 10 ⁴ V / cm corresponding to the upper and lower limits of a normal development contrast potential in order to achieve high image quality. It is preferably Ωcm. If the volume resistivity of the carrier is less than 10 ⁶ Ωcm, the reproducibility of fine lines is poor, and toner fog is likely to occur on the background due to charge injection. Further, if the volume specific resistance of the carrier is larger than 10 ¹⁴ Ωcm, reproduction of black solid and halftone becomes worse. In addition, the amount of carrier transferred to the image carrier increases, and the image carrier is easily scratched.

  The content ratio of the toner and the carrier contained in the developer of the present invention is preferably in the range of 2:98 to 15:85, and more preferably in the range of 3:97 to 10:90.

(Image forming method)
<Image forming apparatus>
The image forming apparatus of the present invention includes an electrostatic latent image forming unit that forms a latent image on an image carrier (hereinafter, also referred to as “photosensitive member”), and the latent image is developed with toner to be visible. A developing unit that forms an image; a transfer unit that transfers the visible image to a recording medium; and a cleaning unit that removes toner remaining on the image carrier after the transfer using a cleaning blade. Become. The toner for forming an electrostatic latent image of the present invention described above is used as the toner, and the pressing pressure of the cleaning blade against the image holding member is 3.9 × 10 ^{−2 to} 6.9 × 10 ⁻² mN / It is characterized by being cm.
Hereinafter, the image forming apparatus of the present invention will be described focusing on the photosensitive member (image holding member) and the cleaning blade.

(Photoconductor)
The photoreceptor (image carrier) used in the image forming apparatus of the present invention is not particularly limited, and a conventionally known photoreceptor can be used. For example, an organic photosensitive layer is formed on a conductive support. A photoreceptor is preferably used. The organic photosensitive layer includes at least a charge generation layer formed by binding a charge generation material with a suitable resin as a binder (binder resin), and a charge transport layer in which the charge transport material is dispersed or dissolved in the binder resin. In addition, an undercoat layer, a protective layer, and the like can be formed as necessary.

(Cleaning blade)
The cleaning blade used in the image forming apparatus of the present invention is a cleaning blade for removing residual toner by pressing against the photosensitive member. In particular, when the average shape factor SF1 of the toner used in the image forming apparatus is 110 to 125 (so-called spherical toner), it is preferable to set the pressing pressure of the cleaning blade high because the toner cleaning property becomes a problem. Is preferably 3.9 × 10 ^{−2 to} 6.9 × 10 ⁻² mN / cm. When the pressing pressure is within the above range, the above-described second inorganic particles (large-diameter external additive) cause scratches on the photosensitive member. However, the use of the toner of the present invention causes remarkable scratches. Can be suppressed.
The pressing pressure will be described later in detail.

  The material of the cleaning blade is not particularly limited as long as it is an elastic body that satisfies the above physical properties, and various elastic bodies can be used. As a specific elastic body, an elastic body such as polyurethane, silicone rubber, nitrile rubber, chloroprene rubber or the like can be used.

Examples of polyurethane elastic bodies include polyurethanes generally synthesized through addition reactions of isocyanates with polyols and various hydrogen-containing compounds.
Examples of the polyol (component) include polyether polyols such as polypropylene glycol and polytetramethylene glycol; polyester polyols such as adipate polyol, polycaprolactam polyol, and polycarbonate polyol.
As the isocyanate (component), aromatic polyisocyanates such as tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, toluidine diisocyanate; hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, dicyclohexylmethane diisocyanate Aliphatic polyisocyanates such as, etc. can be used.

By preparing a urethane prepolymer from any of the above polyols and any of the above isocyanates, adding a curing agent thereto, pouring it into a predetermined mold, crosslinking and curing, and then aging at room temperature Can be manufactured.
As the curing agent, a dihydric alcohol such as 1,4-butanediol and a trihydric or higher polyhydric alcohol such as trimethylolpropane or pentaerythritol are usually used in combination.

(Charging device)
In general, the charging device includes a contact-type charging device and a non-contact-type charging device, and is not particularly limited in the present invention. However, in recent years, a non-charging method using a corona discharge that has been used conventionally has been used. The technology is shifting from a contact charging method to a contact charging method using an electrostatic latent image carrier contact member, which is preferable from the viewpoint of environmental protection. Further, the contact charging method can save space compared to the non-contact charging method, and is a charging method suitable for a small machine.
In the contact charging method, a conductive elastic roller or a charging brush is brought into contact with the electrostatic latent image holding member, and the electrostatic latent image holding member is uniformly charged while applying a voltage to the conductive elastic roller. . In these contact charging methods, discharge is likely to occur immediately before and immediately after the charger contacts the electrostatic latent image holding member. Therefore, compared to the conventional corona discharge method, discharge products such as nitric acid compounds are likely to be generated, and particularly in the blade cleaning method, the portion where the blade contacts the photoconductor is likely to have high torque.
Therefore, when a contact-type charging device is used, the use of the toner of the present invention can remarkably suppress the occurrence of the scratch.

Next, an example of the image forming apparatus of the present invention is shown in FIG. FIG. 1 is a schematic diagram showing an example of an image forming apparatus of the present invention. In the figure, 10 is an image carrier (photoconductor), 12 is a charging roll, 14 is a laser exposure device, 16 is a developing device, and 18 is a developing device. A transfer roll, 19 is a static elimination lamp, 20 is a cleaning blade, and 22 is a fixing roll.
The image forming apparatus shown in FIG. 1 includes a charging roll 12, a laser exposure device 14, a developing device 16, a transfer roll 18, around the photoconductor 10 along the clockwise direction (the direction of arrow A in the figure). A static elimination lamp 19 and a cleaning blade 20 are arranged.

Here, the charging roll 12 uniformly charges the surface of the photoreceptor 10.
On the other hand, the transfer roll 18 is disposed so as to be in contact with the surface of the photoconductor 10, and the paper P can be inserted in the arrow B direction through the contact portion (transfer portion). In addition, a thermal fixing machine including a pair of fixing rolls 22 is disposed on the arrow B direction side with respect to the transfer unit, and the sheet P that has passed through the transfer unit contacts the pair of fixing rolls 22. Part (fixing part) can be inserted in the direction of arrow B.

The image formation by the image forming apparatus shown in FIG. 1 is performed as follows. First, the surface of the photoreceptor 10 is charged by the charging roll 12. Subsequently, the laser exposure device 14 irradiates the surface of the photosensitive member 10 with a laser beam corresponding to the image information to form an electrostatic latent image. Thereafter, the electrostatic latent image is developed by the developing device 16 and a toner image is formed on the surface of the photoreceptor 10. The toner image is transferred to the surface of the paper P by the transfer unit, and is transported to the fixing unit by a transport unit (not shown). It is formed.
On the other hand, after the transfer, the surface of the photoconductor 10 is neutralized by the static elimination lamp 19, and the cleaning blade 20 is used to remove other deposits such as residual toner and discharge products adhering to the surface of the photoconductor 10 after transfer. Prepare for the next image formation.

Next, FIG. 2 shows a state where the cleaning blade is pressed against the surface of the photoreceptor. In FIG. 2, 2 is a cleaning blade, and 1 is a photoreceptor that rotates in the direction of arrow A. The cleaning blade 2 is pressed against the surface of the photoreceptor 1 by a holding member 3, for example.
Here, when a spherical toner having an average shape factor SF1 of 110 to 125 is used as the toner, the pressing pressure (pressing linear pressure) of the cleaning blade 2 to the photosensitive member is from the viewpoint of obtaining good cleaning properties. It is preferably 3.9 × 10 ^{−2 to} 6.9 × 10 ⁻² N / mm, more preferably 4.2 × 10 ^{−2 to} 5.0 × 10 ⁻² N / mm. .
When cleaning is performed with such a high pressing pressure as in the above range, scratches are easily generated on the surface of the photoreceptor, but the use of the toner of the present invention can remarkably suppress the generation of the scratches.

(Process cartridge)
The image forming apparatus may be an image forming apparatus in which a process cartridge is detachable. Specifically, the process cartridge of the present invention is detachable from the loading portion of the image forming apparatus, and develops a visible image by developing the image carrier and the latent image formed on the image carrier with toner. At least a developing device for forming, and a cleaning device for removing toner remaining on the image carrier using a cleaning blade. The toner has a number average particle size of 30 nm or less and a free surface treatment agent amount of 2 The first inorganic particles having a mass average particle diameter of 80 to 200 nm and the average shape factor SF1 of 110 to 125, The process cartridge is characterized in that a pressing pressure against the image carrier is 3.9 × 10 ^{−2 to} 6.9 × 10 ⁻² mN / cm.

(Image forming method)
The image forming method of the present invention includes an electrostatic latent image forming step of forming a latent image on an image carrier, a developing step of developing the latent image with toner to form a visible image, At least a transfer step for transferring to a recording medium and a cleaning step for removing toner remaining on the image carrier after transfer using a cleaning blade, wherein the toner is free with a number average particle size of 30 nm or less. While containing the 1st inorganic particle whose surface treating agent amount is 2-50 mass%, and the 2nd inorganic particle whose number average particle diameter is 80-200 nm, average shape factor SF1 is 110-125. And the pressing force of the cleaning blade against the image carrier is 3.9 × 10 ^{−2 to} 6.9 × 10 ⁻² mN / cm.

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

First, the measurement method used in this example will be described.
-Number average particle diameter of external additives-
The measurement was performed using a scanning electron microscope (SEM: S-4700, manufactured by Hitachi, Ltd.). The externally added toner particles are observed with a scanning electron microscope (SEM: S-4700, manufactured by Hitachi, Ltd.) in 100 fields (50000 times), and circular particles corresponding to the image area of each external additive. Were measured at 1000 locations, and the average value was taken as the number average particle size of the external additive. In the case of composite external addition, mapping was performed at an acceleration voltage of 20 kV using an energy dispersive X-ray analyzer EMAX model 6923H (manufactured by HORIBA) attached to the electron microscope S4100, and the type of external additive was determined.

-Amount of free surface treatment agent for external additives-
2 g of toner is added to 40 ml of an aqueous solution of 0.2% surfactant (polyoxyethylene (10) octylphenyl ether having a polyoxyethylene polymerization degree of 10 manufactured by Wako Pure Chemical Industries, Ltd.) so that the toner gets wet with the aqueous solution. Disperse thoroughly. In this state, an ultrasonic homogenizer US300T (manufactured by Nippon Seiki Seisakusho) was used, and ultrasonic vibration with an output of 20 W and a frequency of 20 kHz was applied for 1 minute to desorb the additive particles. Thereafter, the toner is separated under conditions of 3000 rpm × 7 minutes through a 50 ml centrifuge with a sedimentation tube (compact cooling high-speed centrifuge Model M160 IV, manufactured by Sakuma Seisakusho Co., Ltd.), and the supernatant liquid is separated into a membrane filter (Nippon Millipore (Japan Millipore ( After removal with FHLP02500), the membrane was further removed with a membrane filter having a pore size of 0.22 μm (GSEP047SO) and a pore size of 0.025 μm (VSWP02500), and then the furnace liquid was dried. If the sample amount required for measurement could not be recovered, the same operation was repeated until the sample amount required for measurement could be recovered. NMR measurement was performed using 10 mg of the dried residue.
Proton NMR was measured using AL-400 (magnetic field 9.4T (H nucleus 400 MHz)) manufactured by JEOL. A sample tube (5 mmφ) made of zirconia is filled with a sample, a deuterated chloroform solvent, and TMS as a reference substance. This sample tube is set, and for example, measurement is performed at a frequency: Δ87 kHz / 400 MHz (= Δ20 ppm), measurement temperature: 25 ° C., integration number: 16 times, resolution 0.24 Hz (about 32000 points), free surface treatment agent It converted into the amount of free surface treating agents using the analytical curve from the peak intensity of origin. For example, when dimethyl silicone oil is used as the free surface treatment agent, NMR measurement is performed on the untreated external additive base material and dimethyl silicone oil (shake about 5 levels), and the amount of free surface treatment agent And a calibration curve of NMR peak intensity.

-Toner average shape factor SF1-
SF1 is obtained by the following formula (1).
SF1 = (ML ² / A) × (π / 4) × 100 (1)
In Expression (1), ML represents the maximum toner length, A represents the projected area of the toner, and SF1 = 100 in the case of a true sphere. As a specific method for obtaining the shape factor, a toner image is taken from an optical microscope into an image analyzer (LUZEX III: manufactured by Nireco Corporation), an equivalent circle diameter is measured, and the maximum length and area are calculated. This was done by determining the value of SF1 in the above formula for each particle.

-Volume average particle diameter of toner-
The volume average particle size (cumulative volume average particle size D50) of the toner was measured using Coulter Multisizer II (Beckman-Coulter) and the electrolyte using ISOTON-II (Beckman-Coulter). In the measurement, 0.5 to 50 mg of a measurement sample is added to 2 ml of a 5% aqueous solution of a surfactant (sodium alkylbenzenesulfonate) as a dispersant, and this is added to 100 to 150 ml of an electrolytic solution. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment for 1 minute with an ultrasonic disperser, and the particle size distribution of particles having a diameter in the range of 2 to 60 μm is measured using a 100 μm aperture as the aperture diameter by Coulter Multisizer II. . The number of particles to be sampled is 50,000. For the particle size range (channel) divided on the basis of the particle size distribution measured in this way, the cumulative distribution of the volume is drawn from the smaller diameter side, and the particle size that becomes 50% cumulative is the cumulative volume average particle size D50. It was defined as

-Toner powder flowability-
Using a powder characteristic combination measuring device (powder tester PT-D) manufactured by Hosokawa Micron Corporation, sieves having openings of 53 μm, 45 μm, and 38 μm were arranged in series from the upper stage, and 2 g of accurately weighed on the 53 μm sieve. The toner was added, and the vibration was applied for 90 seconds with an amplitude of 1 mm, and the toner mass on each sieve after vibration was measured, and calculated using the following formula. In addition, the sample used what was left to stand in 25 degreeC / 50% RH environment for 24 hours, and the measurement was performed in 25 degreeC / 50% RH environment.
(Normal temperature cohesion) = (W ₅₃ × 50) + (W ₄₅ × 30) + (W ₃₈ × 10) (2)
(W ₅₃ represents the mass of the developer remaining on the sieve having an aperture of 53 μm, W ₄₅ represents the mass of the developer remaining on the sieve having an aperture of 45 μm, and W ₃₈ represents a sieve having an aperture of 38 μm. This represents the mass of the developer remaining on the top.)

<Production of first inorganic particles (1)>
100 parts of hydrophilic silica (AEROSIL200, manufactured by Nippon Aerosil Co., Ltd.) prepared by a gas phase method is dispersed in 1000 parts of a toluene solution, and 60 parts of decyltrimethoxysilane (KBM-3103, manufactured by Shin-Etsu Silicone) is added to ultrasonic waves. After applying toluene, the toluene was distilled off with an evaporator, and after heating at 150 ° C. for 1 hour, the mixture was pulverized to obtain the first inorganic particles (1) which are small diameter external additives having a number average particle diameter of 12 nm. Obtained. The amount of the free surface treatment agent is shown in Table 1 below.

<Preparation of first inorganic particles (2)>
100 parts of hydrophilic silica (AEROSIL 50, manufactured by Nippon Aerosil Co., Ltd.) prepared by a gas phase method is dispersed in 1000 parts of a toluene solution, and 80 parts of carbinol-modified silicone oil (X-22-170DX, manufactured by Shin-Etsu Silicone) is added. After applying ultrasonic waves, toluene was distilled off with an evaporator, and after heating at 150 ° C. for 1 hour, the mixture was pulverized and first inorganic particles (small-size external additives having a number average particle size of 30 nm) ( 2) was obtained. The amount of the free surface treatment agent is shown in Table 1 below.

<Production of first inorganic particles (3)>
100 parts of hydrophilic titania (F-6, manufactured by Showa Denko KK) prepared by a gas phase method is dispersed in 1000 parts of a toluene solution, and 60 parts of dimethyl silicone oil (KF-96 (50 cs), manufactured by Shin-Etsu Silicone) is added. Then, after applying ultrasonic waves, toluene is distilled off by an evaporator, and further heating is performed at 150 ° C. for 1 hour, followed by pulverization, and first inorganic particles which are small diameter external additives having a number average particle diameter of 15 nm. (3) was obtained. The amount of the free surface treatment agent is shown in Table 1 below.

<Production of first inorganic particles (4)>
Disperse 100 parts of hydrophilic titania (F-6, manufactured by Showa Denko KK) prepared by vapor phase method in 1000 parts of toluene solution, and add 12 parts of methacryl-modified silicone oil (X-22-174DX, manufactured by Shin-Etsu Silicone). Then, after applying ultrasonic waves, toluene is distilled off by an evaporator, and further heating is performed at 150 ° C. for 1 hour, followed by pulverization, and first inorganic particles which are small diameter external additives having a number average particle diameter of 15 nm. (4) was obtained. The amount of the free surface treatment agent is shown in Table 1 below.

<Preparation of inorganic particles (5) for comparison>
Hydrophobic silica (OX50, manufactured by Nippon Aerosil Co., Ltd.) 100 parts produced by a gas phase method is dispersed in 1000 parts of a toluene solution, and 44 parts of decyltrimethoxysilane (KBM-3103, manufactured by Shin-Etsu Silicone) is added to ultrasonic waves. After applying toluene, toluene was distilled off with an evaporator, and heating was further performed at 150 ° C. for 1 hour, followed by pulverization to obtain inorganic particles (5) having a number average particle diameter of 40 nm. The amount of the free surface treatment agent is shown in Table 1 below.

<Production of inorganic particles (6) for comparison>
100 parts of hydrophilic silica (Aerosil 200 manufactured by Nippon Aerosil Co., Ltd.) prepared by a gas phase method is dispersed in 1000 parts of a toluene solution, and 150 parts of carbinol-modified silicone oil (X-22-170DX, manufactured by Shin-Etsu Silicone) is added. After applying ultrasonic waves, toluene was distilled off with an evaporator, and heating was further performed at 150 ° C. for 1 hour, followed by pulverization to obtain inorganic particles (6) having a number average particle diameter of 12 nm. The amount of the free surface treatment agent is shown in Table 1 below.

<Preparation of inorganic particles (7) for comparison>
100 parts of hydrophilic silica (Aerosil 200, manufactured by Nippon Aerosil Co., Ltd.) prepared by a gas phase method is dispersed in 1000 parts of a toluene solution, and 21 parts of dimethyl silicone oil (KF-96 (50 cs), manufactured by Shin-Etsu Silicone) is added. After applying ultrasonic waves, toluene was distilled off with an evaporator, and heating was further performed at 150 ° C. for 1 hour, followed by pulverization to obtain inorganic particles (7) having a number average particle diameter of 12 nm. The amount of the free surface treatment agent is shown in Table 1 below.

<Production of second inorganic particles (A)>
The silica sol obtained by the sol-gel method is treated with HMDS (hexamethyldisilazane), dried, and pulverized to obtain a sphericity Ψ = 0.70 and a number average particle diameter = 120 nm (standard deviation = 20 nm). The 2nd inorganic particle (A) which is an agent was obtained.

<Preparation of second inorganic particles (B)>
Silica sol obtained by the sol-gel method is subjected to HMDS treatment, dried and pulverized to give second inorganic particles (Σ = 0.90, number average particle size = 80 nm (standard deviation = 15 nm)) as a large-diameter external additive ( B) was obtained.

<Production of second inorganic particles (C)>
Silica sol obtained by the sol-gel method is subjected to HMDS treatment, dried and pulverized to give second inorganic particles (Φ = 0.85, number average particle size = 135 nm (standard deviation = 27 nm)) which are large-diameter external additives ( C) was obtained.

[Production of colored particles]
<Preparation of resin particle dispersion>
・ Styrene 296 parts ・ N-butyl acrylate 104 parts ・ Acrylic acid 6 parts ・ Dodecanethiol 9 parts ・ Divinyl adipate 1.6 parts (above, manufactured by Wako Pure Chemical Industries, Ltd.)
10 parts of a nonionic surfactant (Sanyo Kasei Co., Ltd .: Nonipol 400) and an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC) 8 Ion exchange in which 8 parts of ammonium persulfate (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved while adding and dissolving in 610 parts of ion-exchanged water, dispersing in a flask, emulsifying, and slowly mixing for 15 minutes. 50 parts of water was added and nitrogen substitution was performed at 0.1 liter / min for 20 minutes. Thereafter, while stirring the inside of the flask, the contents are heated in an oil bath until the content reaches 70 ° C., and emulsion polymerization is continued for 5 hours, and a resin particle dispersion liquid having an average particle size of 200 nm and a solid content concentration of 40% ( 1) was prepared. When a portion of the dispersion was left on an oven at 100 ° C. to remove moisture, DSC (differential scanning calorimeter) measurement was performed. The glass transition point was 53 ° C. and the weight average molecular weight was 33,000. Met.

<Preparation of colorant dispersion (1A)>
・ Cyan pigment B15: 3 (Daiichi Seika Co., Ltd .: Cyanine Blue 4937) 100 parts ・ Anionic surfactant (Neogen RK: manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 10 parts ・ Ion-exchanged water 490 parts Colorant dispersion (1A) in which colorant (Cyan pigment) particles having an average particle size of 250 nm are dispersed by mixing and dissolving, and dispersing for 10 minutes using a homogenizer (Ultra Turrax T50: manufactured by IKA) Was prepared.

<Preparation of colorant dispersion (2A)>
The colorant is C.I. I. A colorant dispersion (2A) was prepared in the same manner as the colorant dispersion (1A), except that it was changed to CI Pigment Red 122 (quinacridone pigment: manufactured by Dainichi Seika Co., Ltd .: Chromofine Magenta 6887). The average particle size was 220 nm.

<Preparation of colorant dispersion (3A)>
The colorant is C.I. I. A colorant dispersion (3A) was prepared in the same manner as the colorant dispersion (1A) except that it was changed to CI Pigment Yellow 74 (monoazo pigment: manufactured by Dainichi Seika Co., Ltd .: Seika First Yellow 2054). The average particle size was 240 nm.

<Preparation of Colorant Dispersion (4A)>
A colorant dispersion (4A) was prepared in the same manner as the colorant dispersion (1A) except that the colorant was changed to carbon black (manufactured by Cabot: Regal 330). The average particle size was 200 nm.

<Preparation of release agent dispersion A>
Paraffin wax 100 parts (HNP0190: manufactured by Nippon Seiwa Co., Ltd., melting point 85 ° C.)
・ 10 parts of anionic surfactant (Lion Corp .: Lipar 860K)
・ Ion-exchanged water 400 parts The above components were dispersed in a round stainless steel flask using a homogenizer (Ultra Turrax T50: manufactured by IKA) for 10 minutes, and then dispersed with a pressure discharge homogenizer to obtain an average particle size. A release agent dispersion A in which release agent particles having a diameter of 550 nm are dispersed was prepared.

(Production of colored particles Cyan)
-Resin particle dispersion 320 parts-Colorant dispersion (1A) 80 parts-Release agent dispersion A 96 parts-Aluminum sulfate (manufactured by Wako Pure Chemical Industries, Ltd.) 1.5 parts-Ion-exchanged water 1270 parts or more The components were housed in a round stainless steel flask with a temperature control jacket and dispersed for 5 minutes at 5,000 rpm using a homogenizer (IKA, Ultra Tarrax T50), then moved to the flask, 25 ° C., The mixture was left stirring for 4 minutes with 4 paddles. Thereafter, the mixture was heated with a mantle heater while stirring and heated at a heating rate of 1 ° C./min until the inside reached 48 ° C., and held at 48 ° C. for 20 minutes. Next, 80 parts of the resin particle dispersion was gradually added and kept at 48 ° C. for 30 minutes, and then a 1N aqueous sodium hydroxide solution was added to adjust the pH to 6.5.
Thereafter, the temperature was raised to 95 ° C. at a rate of 1 ° C./min and held for 30 minutes. A 0.1N nitric acid aqueous solution was added to adjust the pH to 4.8, and the mixture was allowed to stand at 95 ° C. for 2 hours. Thereafter, the 1N aqueous sodium hydroxide solution was further added to adjust the pH to 6.5 and left at 95 ° C. for 8 hours. Thereafter, it was cooled to 30 ° C. at 5 ° C./min.
The resulting toner particle dispersion was filtered, (A) 2,000 parts of ion-exchanged water at 35 ° C. was added to the obtained toner particles, (B) allowed to stand for 20 minutes, and (C) then filtered. After the operations from (A) to (C) were repeated 5 times, the toner particles on the filter paper were transferred to a vacuum dryer and dried at 45 ° C. and 1,000 Pa or less for 10 hours. The reason why the pressure is 1,000 Pa or less is that the above-mentioned toner particles are in a water-containing state, and in the initial stage of drying, the water freezes even at 45 ° C. and then the water sublimates. This is because the pressure does not become constant. However, it was stable at 100 Pa at the end of drying. After returning the inside of the dryer to normal pressure, this was taken out to obtain colored particles Cyan.
The obtained colored particles Cyan had a volume average particle diameter D50 of 5.8 μm, a number average particle size distribution index GSDp of 1.23, and a shape factor SF1 of 120.

(Production of colored particles Magenta)
The colorant dispersion (1A) is changed to the colorant dispersion (2A), which is a magenta colorant, and left for 8 hours in an environment of 95 ° C. and pH 6.5, in an environment of 95 ° C. and pH 4.0. A colored particle Magenta was produced in the same manner as the colored particle Cyan, except that it was changed to leave for 3 hours.
The obtained colored particles Magenta had a volume average particle size D50 of 5.6 μm, a number average particle size distribution index GSDp of 1.22, and a shape factor SF1 of 116.

(Production of colored particles Yellow)
The colorant dispersion (1A) is changed to the colorant dispersion (3A), which is a yellow colorant, and left for 8 hours in an environment at 95 ° C. and pH 6.5, in an environment at 95 ° C. and pH 4.0. Colored particles Yellow were produced in the same manner as the colored particles Cyan, except that it was changed to leave for 5 hours.
The obtained colored particles Yellow had a volume average particle diameter D50 of 5.8 μm, a number average particle size distribution index GSDp of 1.21, and a shape factor SF1 of 112.

(Manufacture of colored particles Kuro)
Colored particles Kuro were produced in the same manner as the colored particles Cyan except that the colorant dispersion (1A) was changed to the colorant dispersion (4A), which was a black colorant.
The obtained colored particles Kuro had a volume average particle diameter D50 of 5.7 μm, a number average particle size distribution index GSDp of 1.23, and a shape factor SF1 of 125.

<Production of carrier>
Ferrite particles (average particle size: 50 μm) 100 parts Toluene 14 parts Styrene-methyl methacrylate copolymer 2 parts (component ratio: 90/10, weight average molecular weight Mw 78000)
Carbon black (R330: manufactured by Cabot Corporation) 0.2 parts First, the above components excluding ferrite particles are stirred with a stirrer for 10 minutes to prepare a dispersed coating solution, and then the coating solution and ferrite particles are vacuumed After putting in a degassing type kneader and stirring at 60 ° C. for 30 minutes, the carrier was obtained by further depressurizing while heating and degassing and drying. This carrier had a volume resistivity of 10 ¹¹ Ωcm when an applied electric field of 1000 V / cm was applied.

[Example 1]
Using 100 parts of each of the colored particles Kuro, Cyan, Magenta, and Yellow, 1 part of the first inorganic particles (1) and 1.5 parts of the second inorganic particles (A) were used at a peripheral speed of 32 m / s using a Henschel mixer. After blending for 10 minutes, coarse particles were removed using a 45 μm mesh sieve to obtain toner of each color. 100 parts of the carrier and 5 parts of each toner are stirred for 20 minutes at 40 rpm using a V-blender, and sieved through a sieve having a 177 μm mesh (powder fluidity is Kuro, Cyan, Magenta, Yellow, respectively). 10%, 14%, 12%, 15%).

[Example 2]
100 parts of each of the colored particles Kuro, Cyan, Magenta, and Yellow, 1 part of the first inorganic particles (2) and 1.2 parts of the second inorganic particles (B) are used at a peripheral speed of 32 m / s × 10 using a Henschel mixer. After blending for a minute, coarse particles were removed using a 45 μm mesh sieve to obtain toner of each color. 100 parts of the carrier and 5 parts of each toner are stirred for 20 minutes at 40 rpm using a V-blender, and sieved through a sieve having a 177 μm mesh (powder fluidity is Kuro, Cyan, Magenta, Yellow, respectively). 22%, 25%, 26%, 29%).

[Example 3]
100 parts of each of the colored particles Kuro, Cyan, Magenta, and Yellow are blended with 1.5 parts of the second inorganic particles (C) using a Henschel mixer, and the peripheral speed is 32 m / s × 10 minutes, and further, the first inorganic particles (3) After adding 1 part and blending at a peripheral speed of 20 m / s × 5 minutes, coarse particles were removed using a sieve of 45 μm mesh to obtain toner of each color. 100 parts of the carrier and 5 parts of each toner are stirred for 20 minutes at 40 rpm using a V-blender, and sieved through a sieve having a 177 μm mesh (powder fluidity is Kuro, Cyan, Magenta, Yellow, respectively). 18%, 21%, 22%, 27%).

[Example 4]
1 part of the first inorganic particles (4), 1 part of the second inorganic particles (A), and 1 part of cerium oxide having a number average particle size of 0.7 μm are added to 100 parts of each of the colored particles Kuro, Cyan, Magenta, and Yellow. After blending for 10 minutes at a peripheral speed of 32 m / s × 10 minutes using a Henschel mixer, coarse particles were removed using a sieve of 45 μm mesh to obtain toner of each color. 100 parts of the carrier and 5 parts of each toner are stirred for 20 minutes at 40 rpm using a V-blender, and sieved through a sieve having a 177 μm mesh (powder fluidity is Kuro, Cyan, Magenta, Yellow, respectively). 13%, 15%, 16%, 18%).

[Comparative Example 1]
In the production of each developer of Kuro, Cyan, Magenta, and Yellow of Example 1, except that the inorganic particles for comparison (5) were externally added to the colored particles instead of the first inorganic particles (1), In the same manner as in Example 1, developers of respective colors (powder fluidity of 11%, 13%, 15%, and 17%, respectively, for Kuro, Cyan, Magenta, and Yellow) were obtained.

[Comparative Example 2]
In the production of each developer of Kuro, Cyan, Magenta, and Yellow of Example 1, except that the inorganic particles for comparison (6) were externally added to the colored particles instead of the first inorganic particles (1), In the same manner as in Example 1, developers of each color (powder fluidity of 30%, 32%, 36%, and 37% for Kuro, Cyan, Magenta, and Yellow, respectively) were obtained.

[Comparative Example 3]
In the production of each developer of Kuro, Cyan, Magenta, and Yellow of Example 1, except that the inorganic particles for comparison (7) were externally added to the colored particles instead of the first inorganic particles (1), In the same manner as in Example 1, developers of each color (powder fluidity of 12%, 14%, 17%, and 20% for Kuro, Cyan, Magenta, and Yellow, respectively) were obtained.

(Evaluation)
In an example and a comparative example using an image forming apparatus (a modified machine in which the pressing pressure of the cleaning blade against the photoconductor is changed to 4.0 × 10 ⁻² mN / cm in the Docu Center Color 320 manufactured by Fuji Xerox Co., Ltd.) With the obtained developer, an image formation test was performed in a predetermined environment (3 ° C., 10 RH%).
First, the image forming apparatus was left overnight at 30 ° C. and 75%, and then left overnight at 3 ° C. and 3%. Thereafter, the respective developers were set at the Kuro, Yellow, Magenta, and Cyan positions.
An image was formed on A3 paper (P paper, manufactured by Fuji Xerox Co., Ltd.) using “Electrophotographic Society of Japan Test Chart No. 5-1”, and the operation of putting a pause for 5 minutes every time 100 sheets were output was repeated. Each time 1000 sheets are output by this operation, the image quality (corresponding to the color of the developer used) together with the image quality (determined that the image quality is deteriorated due to insufficient toner cleaning property if there are streaks on the blank paper). The scratch on the surface of the image carrier was visually evaluated.

1 is a schematic diagram illustrating an example of an image forming apparatus of the present invention. It is a schematic diagram showing a state where the cleaning blade is pressed against the surface of the photoreceptor.

Explanation of symbols

10 Image carrier (photoreceptor)
12 Charging roll 14 Laser exposure device 16 Developer 18 Transfer roll 19 Static elimination lamp 20 Cleaning blade

Claims (3)

  Containing first inorganic particles having a number average particle size of 30 nm or less and a free surface treating agent amount of 2 to 50% by mass, and second inorganic particles having a number average particle size of 80 to 200 nm. An electrostatic latent image developing toner. An image carrier, an electrostatic latent image forming unit for forming a latent image on the image carrier, a developing unit for developing the latent image with toner to form a visible image, and the visible image on a recording medium. A transfer unit that transfers, and a cleaning unit that removes toner remaining on the image carrier after transfer using a cleaning blade;
The toner includes first inorganic particles having a number average particle diameter of 30 nm or less and a free surface treating agent amount of 2 to 50% by mass, and second inorganic particles having a number average particle diameter of 80 to 200 nm. And the average shape factor SF1 is 110 to 125,
An image forming apparatus, wherein the pressing pressure of the cleaning blade against the image holding member is 3.9 × 10 ^{−2 to} 6.9 × 10 ⁻² mN / cm. It is detachable from the loading part of the image forming apparatus,
An image carrier, a developing device that develops a latent image formed on the image carrier with toner to form a visible image, and a cleaning device that removes toner remaining on the image carrier using a cleaning blade; Having at least
The toner includes first inorganic particles having a number average particle diameter of 30 nm or less and a free surface treating agent amount of 2 to 50% by mass, and second inorganic particles having a number average particle diameter of 80 to 200 nm. And the average shape factor SF1 is 110 to 125,
A process cartridge, wherein the pressing pressure of the cleaning blade against the image carrier is 3.9 × 10 ^{−2 to} 6.9 × 10 ⁻² mN / cm.

Images