JP2003241417A - Toner for electrostatic latent image developing, image forming method and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide toner for electrostatic latent image developing by which uniformity of half-tone is good by reducing dust in transferring caused when the particle diameter of a toner particle and its shape are made uniform and which is superior in its reproduction of a halftone dot, and to provide an image forming method using it and an image forming apparatus. <P>SOLUTION: In the toner for electrostatic latent image developing, an average value of roundness is 0.94 to 0.98, an average value of the diameter which is equivalent to that of a sphere is 2.6 to 7.7 μm and the inclination of the roundness which is equivalent to that of the sphere is -0.050 to -0.010. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic latent image developing toner, an image forming method using the same, and an image forming apparatus.

[0002]

2. Description of the Related Art In recent years, with the development of digital image processing technology, digital image formation has become the mainstream also in an image forming method by an electrostatic latent image developing system such as an electrophotographic system.

A digital image forming method is 1200
It is basically based on the visualization of small dot images such as dpi (dots / inch; the number of dots per 2.54 cm), and high image quality technology that faithfully reproduces these small dot images is required.

In order to improve the image quality as described above, the particle size of the electrostatic latent image developing toner (sometimes simply referred to as toner) is being reduced. In the past, in image formation by an electrostatic latent image developing method such as an electrophotographic method, a so-called pulverized toner obtained by classifying toner powder obtained by mixing a binder resin (binder resin) and a pigment, kneading and pulverizing the mixture is used. It has been used mainly. However, the toner obtained through such a manufacturing process has a limit in reducing the toner particle size and making the particle size distribution uniform (see, for example, Patent Document 1). It is difficult to reduce the toner particle size and achieve uniform particle size distribution and shape. Therefore, it is difficult to achieve a sufficiently high image quality in an electrophotographic image using such a pulverized toner.

In recent years, so-called polymerization method toners obtained by a suspension polymerization method or an emulsion polymerization method as a means for achieving a reduction in the particle size of the toner particles and a uniform particle size distribution and shape (see, for example, Patent Document 2). ) Is attracting attention. The polymerization toner is used as a toner by uniformly dispersing a raw material monomer in an aqueous system and then polymerizing it. There are various methods among them, but the method that attracts the most attention is a method of associating (aggregating and fusing) the resin particles and the colorant particles obtained by the suspension polymerization method or the emulsion polymerization method. . Since it is easy to produce toner particles with a small particle size and a uniform particle size distribution, practical studies are underway, but the manufacturing technology is still in the development stage.

Then, it is ideal if the particle size and shape of the toner particles are completely uniform.
The present inventors have already learned from the knowledge of the following two items.

(1) When a group of toner particles having exactly the same charge and mass as point charges are released from an electric field from a dot-shaped electrostatic latent image to a transfer material, they have uniform repulsive forces. , The dots tend to scatter radially from the image.

As a result, it has been found that dust generated at this time disturbs halftone dot reproducibility and deteriorates halftone uniformity.

(2) Further, if the toner is a true sphere and has the same particle diameter, the density for filling the rectangular package image is π / 4, and this density is such that the toner particle diameters are not uniform. We had the knowledge that it would be inferior to what it was.

[0010]

[Patent Document 1] Japanese Patent Laid-Open No. 2000-250255

[0011]

[Patent Document 2] Japanese Patent Laid-Open No. 2001-5219

[0012]

The present invention has been made to solve the above problems.

The object of the present invention is to reduce the transfer dust that occurs when the particle size and shape of the toner particles are made uniform, to achieve good halftone uniformity, and to achieve excellent dot reproducibility. To provide a toner for developing a latent charge image, an image forming method and an image forming apparatus using the same.

[0014]

DISCLOSURE OF THE INVENTION The inventors of the present invention have made relatively large toner particles present in a toner having a small particle size and a uniform particle size distribution and shape in a range that does not adversely affect the image quality. , And found that the fixability is significantly improved.

However, the "relatively large toner particles" to be added here, unless the shape and particle size distribution are sufficiently controlled like the component having a reduced diameter, cause selective development and selective transfer due to the difference in particle size. There's a problem.

That is, in general, with a toner having a constant shape and particle size distribution, the large toner particles are developed and transferred. If the selective development and selective transfer are continued, the toner is scattered around the halftone image, and the resolution is deteriorated. In addition, a small-diameter toner component accumulates in the developing device and fusion occurs on the developing roller, which may cause problems such as fogging due to toner charge inhibition and toner scattering. Further, in the transfer step, problems such as transfer omission and image unevenness due to filming of the photoconductor occur.

Therefore, the "relatively large toner particles" are not perfectly spherical but have a different shape, and the toner mainly used for image formation has a particle size and a circular shape so that the toner becomes closer to a spherical shape and has a uniform particle size distribution. The present inventors have found that it is necessary to design so as to have a gradient every degree, and have completed the present invention.

That is, the object of the present invention is achieved by adopting any of the following constitutions. [1] The average value of circularity is 0.94 to 0.98,
Moreover, the average value of the equivalent circle diameter is 2.6 to 7.4 μm, and the inclination of the circularity with respect to the equivalent circle diameter is −0.050 to −0.0.
10. A toner for developing an electrostatic latent image, which is 10.

[2] The average equivalent circle diameter is 3.4 to 6.
Is 6 μm, and the slope of the circularity with respect to the equivalent circle diameter is −0.
The toner for developing an electrostatic latent image according to item [1], which is 040 to -0.020.

[3] Equivalent circle diameter d _{10 at} cumulative 10%
And the equivalent circle diameter d ₉₀ at a cumulative 90%, d ₉₀ / d ₁₀
Is 1.2 to 1.8. The toner for developing an electrostatic latent image according to [1] or [2], wherein

[4] At least a polymerizable monomer is obtained by polymerizing in an aqueous medium, which is characterized by [1] to
[3] The toner for developing an electrostatic latent image according to any one of [3].

[5] At least resin particles are obtained by salting out / fusing in an aqueous medium. [1] to
[4] The toner for developing an electrostatic latent image according to any one of [4].

[6] BET specific surface area of 1.1 to 4.0
m ² / g, the surface abundance of silicon atoms measured by ESCA is 6 to 12 area%, and the abundance of carbon atoms is 50 to 75 area%.
[5] The toner for developing an electrostatic latent image according to any one of [1] to [5].

[7] In the image forming method, which comprises a step of visualizing the electrostatic latent image formed on the photoreceptor to a visible image, transferring the visible image onto a recording paper, and heat fixing the visible image, [1] To [5], the image forming method using the electrostatic latent image developing toner according to any one of [1] to [5].

[8] An image forming apparatus using the image forming method described in [7], wherein the photosensitive member is irradiated by digital exposure.

[0026]

[9] A two-component developer obtained by mixing the electrostatic latent image developing toner according to any one of [1] to [5] with a magnetic carrier.

The method for producing the toner for developing an electrostatic latent image of the present invention is not particularly limited, but it is a so-called polymerization method, that is, a method in which at least a polymerizable monomer is polymerized in an aqueous medium to obtain toner particles. Is preferred. Further, the toner particles are preferably obtained by salting out / fusing the obtained resin particles in an aqueous medium. This is because it is possible to produce toner particles having a small particle size and a controlled particle size distribution and shape by salting out / fusing resin particles produced by the polymerization method, particularly resin particles in an aqueous medium. is there.

As for the shape of the toner of the present invention, when 2000 or more toner particles having a particle diameter of 1 μm or more are measured, the average value of the circularity (shape coefficient) represented by the following formula is 0.94 to
It is 0.98, more preferably 0.94 to 0.97.

Circularity = (perimeter of equivalent circle) / (perimeter of toner particle projection image) = 2π × (projection area of particle / π) ^1/2 / (perimeter of toner particle projection image) where: The equivalent circle is a circle having the same area as the toner particle projected image, and the equivalent circle diameter is the diameter of the equivalent circle.

As a method of measuring the circularity, F
It can be measured by PIA-2000 (manufactured by Sysmec Corporation). At this time, the equivalent circle diameter is defined by the following equation.

Equivalent circle diameter = 2 × (projected area of particles / π) ^{1/2 Further} , in the shape of the toner of the present invention, the average value of the equivalent circle diameter is
It is in the range of 2.6 to 7.4 μm, and the inclination of the circularity with respect to the equivalent circle diameter is −0.050 to −0.010. More preferably, the average equivalent circle diameter is from 3.4 to
6.6 μm, and the slope of the circularity with respect to the equivalent circle diameter is −
It is preferably 0.040 to -0.020.

The inventors of the present invention make particles having a large mass and a low circularity develop like a wedge on a dot latent image, and develop particles having a small diameter and a high circularity so as to fill the gap. , So that the state of the closest packing was obtained.
Then, even if dust occurs in the transfer, it can be seen that the dust is emitted from the particles with a small mass, and the outline of the dot remains firmly. However, if the circularity of the particles and the equivalent circle diameter are discretely distributed, the effect is insufficient, and there is a problem that selective development and selective transfer are likely to occur.

Therefore, the present inventors have for the first time derived the concept of continuously changing the degree of circularity with respect to the equivalent circle diameter, and have found the range in which the effect described in the present invention is exhibited. Finally, the present invention Has been completed.

The slope of the circle equivalent diameter is measured by measuring the circle equivalent diameter of the toner particles with a flow type particle image analyzer FPIA-2000, and the relationship with the circularity is shown by the horizontal axis: circle equivalent diameter (μm). ) -Vertical axis: drawn as circularity, and if the first-order correlation (y = αx + b) is seen, α is the slope of the circle equivalent diameter.

At this time, from the viewpoint of improving the uniformity of charging and the uniformity of halftone, R ² (square of R) is 0.35 to
0.95 is preferable. Here, R is represented by the following general formula (1).

General formula (1) R = A / B In the formula, A and B each represent the following formula.

A = nΣXY− (ΣXΣY) B = (nΣX ² − (ΣX) ² ) × ((nΣY ² ) − (Σ
Y) ² ) X represents a circle equivalent diameter (μm), and Y represents circularity.

Further, in order to produce a toner having an inclination of a circle equivalent diameter, irregular-shaped toner particles having a slightly larger particle diameter may be mixed with spherical toner particles having a smaller particle diameter. Alternatively, in the method of assembling toner particles by associating resin particles described later, after adding an aggregating agent in the associating step, a stirring blade shape is appropriately selected, stirring strength is controlled, and a shearing force is applied to larger particles. As an easy condition, a method of shifting to filtration and drying steps may be used. Preferably, the toner production apparatus and the above-mentioned flow type particle image analysis apparatus are connected in-line, and the production is performed while monitoring the inclination α and appropriately adjusting the conditions.

Preferably, after adding a terminating agent for stopping the salting-out / fusion, the toner particles are further grown by 0.2 to 1.0 μm by, for example, re-addition of the salting-out agent or addition of a surfactant. It can be controlled to fall within the scope of the present invention.

Further, in the present invention, from the viewpoint of making the charge amount distribution of the toner suitable, the equivalent circle diameter d ₁₀ at 10 number% in cumulative from the small particle side of the toner particles and 90 number% in cumulative.
Ratio of the circle equivalent diameter d ₉₀ , d ₉₀ / d ₁₀ of 1.2 to
It is preferably 2.0. Particularly preferably 1.3 to
It is 1.8. Within this range, dot dust can be controlled, halftone uniformity is high, and a high-quality image can be obtained.

Further, it is preferable to add silica fine particles as an external additive. In that case, from the viewpoint of suppressing selective transfer and selective development, the BET specific surface area of the toner is 1.1 to.
4.0 m ² / g, the surface abundance of silicon atoms measured by ESCA is 6 area% to 12 area%, and the abundance of carbon atoms is 50.
Area% to 75 area% is preferable.

[0042]

BEST MODE FOR CARRYING OUT THE INVENTION As a method for producing the toner of the present invention, a method for producing particles in an aqueous medium which can be preferably used is described in, for example, JP-A Nos. 63-186253 and 63-282749, JP-A-7-1465
The method described in Japanese Patent Publication No. 83, etc., the method of salting out / fusing resin particles, and the like can be used.

The resin particles used in the production of the toner of the present invention preferably have a weight average particle diameter of 50 to 2000 nm, and these resin particles can be obtained by any of the granulation polymerization methods such as emulsion polymerization, dispersion polymerization and suspension polymerization. good. Resin particles obtained by emulsion polymerization are preferably used.

Hereinafter, examples of the material of the resin particles and the manufacturing method will be described. << Material >> [Monomer] As the polymerizable monomer, a radical-polymerizable monomer is an essential constituent component, and a crosslinking agent can be used if necessary. Further, it is preferable to contain at least one radical-polymerizable monomer having the following acidic group or radical-polymerizable monomer having a basic group.

(1) Radical Polymerizable Monomer The radical polymerizable monomer component is not particularly limited, and conventionally known radical polymerizable monomers can be used.
Further, one kind or a combination of two or more kinds can be used so as to satisfy the required characteristics.

Specifically, aromatic vinyl monomers, acrylic acid ester monomers, methacrylic acid ester monomers, vinyl ester monomers, vinyl ether monomers, mono-olefin monomers Body, diolefin monomer,
A halogenated olefin-based monomer or the like can be used.

As the aromatic vinyl monomer, for example,
Examples thereof include styrene-based monomers such as styrene, methylstyrene and methoxystyrene and derivatives thereof.

Examples of acrylic acid ester-based monomers and methacrylic acid ester-based monomers include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl acrylate, acrylic acid. Benzyl, methyl methacrylate,
Ethyl methacrylate, butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, β-
Examples thereof include ethyl hydroxyacrylate, γ-aminoacrylic acid propyl, stearyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate and the like.

Examples of the diolefin-based monomer include butadiene, isoprene and chloroprene.

(2) Crosslinking Agent As the crosslinking agent, a radical polymerizable crosslinking agent may be added to improve the characteristics of the toner. Radical polymerizable cross-linking agents include divinylbenzene, divinylnaphthalene,
Examples thereof include those having two or more unsaturated bonds such as divinyl ether, diethylene glycol methacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate and diallyl phthalate.

(3) Radical polymerizable monomer having an acidic group or radical polymerizable monomer having a basic group Radical polymerizable monomer having an acidic group or radical polymerizable monomer having a basic group For example, an amine compound such as a carboxyl group-containing monomer, a sulfonic acid group-containing monomer, a primary amine, a secondary amine, a tertiary amine, or a quaternary ammonium salt may be used. it can.

Examples of the radically polymerizable monomer having an acidic group include acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, cinnamic acid, maleic acid monobutyl ester, and carboxylic acid group-containing monomers. Maleic acid monooctyl ester etc. are mentioned.

Examples of the sulfonic acid group-containing monomer include styrene sulfonic acid, allyl sulfosuccinic acid, and octyl allyl sulfosuccinate.

These may have a structure of an alkali metal salt such as sodium or potassium or an alkaline earth metal salt such as calcium.

Examples of the radical polymerizable monomer having a basic group include amine compounds, such as dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, and the quaternary compounds of the above four compounds. An ammonium salt etc. can be mentioned.

As the radical-polymerizable monomer used in the present invention, a radical-polymerizable monomer having an acidic group or a radical-polymerizable monomer having a basic group is contained in an amount of 0.1 to 15 of the whole monomers. The radical-polymerizable cross-linking agent is preferably used in an amount of 0.1 to 10 mass% with respect to the total radical-polymerizable monomers, although it depends on its characteristics.

[Chain Transfer Agent] A commonly used chain transfer agent can be used for the purpose of adjusting the molecular weight.

The chain transfer agent is not particularly limited, and examples thereof include mercaptans such as octyl mercaptan, dodecyl mercaptan, tert-dodecyl mercaptan, carbon tetrabromide and styrene dimer.

[Polymerization Initiator] The radical polymerization initiator used in the present invention can be appropriately used if it is water-soluble.
For example, persulfates (potassium persulfate, ammonium persulfate, etc.), azo compounds (4,4′-azobis-4-cyanovaleric acid and its salts, 2,2′-azobis (2-amidinopropane) salt, etc.) Can be mentioned.

As the polymerization temperature, any temperature may be selected as long as it is at least the minimum radical generation temperature of the polymerization initiator, but for example, a range of 50 ° C. to 90 ° C. is used. However, it is also possible to carry out the polymerization at room temperature or higher by using a combination of a polymerization initiator started at room temperature, for example, hydrogen peroxide-reducing agent (ascorbic acid etc.).

[Surfactant] In order to carry out polymerization using the above-mentioned radically polymerizable monomer, it is necessary to disperse oil droplets in an aqueous medium using a surfactant. The surfactant that can be used in this case is not particularly limited, but the following ionic surfactants can be mentioned as suitable examples.

As the ionic surfactant, sulfonates (sodium dodecylbenzene sulfonate, sodium arylalkyl polyether sulfonate, 3,3-
Disulfone diphenylurea-4,4-diazo-bis-amino-8-naphthol-6-sulfonate sodium, ortho-carboxybenzene-azo-dimethylaniline,
2,2,5,5-tetramethyl-triphenylmethane-
4,4-diazo-bis-β-naphthol-6-sulfonate, etc.), sulfuric acid ester salts (sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, etc.), fatty acid salts (sodium oleate, laurin) Acid sodium salt, sodium caprate, sodium caprylate, sodium caproate, potassium stearate, calcium oleate and the like).

Further, nonionic surfactants can also be used. Specifically, polyethylene oxide, polypropylene oxide, a combination of polypropylene oxide and polyethylene oxide, ester of polyethylene glycol and higher fatty acid, alkylphenol polyethylene oxide, ester of higher fatty acid and polyethylene glycol, ester of higher fatty acid and polypropylene oxide, sorbitan ester. Etc. can be given.

In the present invention, these are mainly used as an emulsifier during emulsion polymerization, but they may be used for other steps or purposes.

[Colorant] Examples of the colorant include inorganic pigments, organic pigments and dyes.

As the inorganic pigment, conventionally known ones can be used. Specific inorganic pigments are exemplified below.

Examples of black pigments include furnace black, channel black, acetylene black,
Carbon black such as thermal black and lamp black, and magnetic powder such as magnetite and ferrite are also used.

These inorganic pigments can be used alone or in combination of two or more as desired. Further, the amount of the pigment added is 2 to 20% by mass, preferably 3 to 15% by mass, based on the polymer.

When used as a magnetic toner, the above-mentioned magnetite can be added. In this case, from the viewpoint of imparting a predetermined magnetic characteristic, 20 to 6 is contained in the toner.
It is preferable to add 0% by mass.

Known organic pigments and dyes can be used. Specific organic pigments and dyes are exemplified below.

As the pigment for magenta or red,
C. I. Pigment Red 2, C.I. I. Pigment Red 3, C.I. I. Pigment Red 5, C.I. I. Pigment Red 6, C.I. I. Pigment Red 7, C.I. I. Pigment Red 15, C.I. I. Pigment Red 16,
C. I. Pigment Red 48: 1, C.I. I. Pigment Red 53: 1, C.I. I. Pigment Red 57:
1, C.I. I. Pigment Red 122, C.I. I. Pigment Red 123, C.I. I. Pigment Red 139,
C. I. Pigment Red 144, C.I. I. Pigment Red 149, C.I. I. Pigment Red 166, C.I.
I. Pigment Red 177, C.I. I. Pigment Red 178, C.I. I. Pigment Red 222 and the like.

Pigments for orange or yellow include C.I. I. Pigment Orange 31, C.I. I. Pigment Orange 43, C.I. I. Pigment Yellow 12,
C. I. Pigment Yellow 13, C.I. I. Pigment Yellow 14, C.I. I. Pigment Yellow 15, C.I.
I. Pigment Yellow 17, C.I. I. Pigment Yellow 93, C.I. I. Pigment Yellow 94, C.I. I.
Pigment Yellow 138, C.I. I. Pigment Yellow 180, C.I. I. Pigment Yellow 185, C.I.
I. Pigment Yellow 155, C.I. I. Pigment Yellow 156 and the like.

As the pigment for green or cyan,
C. I. Pigment Blue 15, C.I. I. Pigment Blue 15: 2, C.I. I. Pigment Blue 15: 3,
C. I. Pigment Blue 16, C.I. I. Pigment Blue 60, C.I. I. Pigment Green 7 and the like.

As the dye, C.I. I. Solvent Red 1, 49, 52, 58, 63, 111,
122, C.I. I. Solvent Yellow 19, 44,
77, 79, 81, 82, 93, 98, 103, 104, 112, 162, C.I. I. Solvent Blue 25, 36, 60, 70, 93,
Id. 95 and the like can be used, and a mixture thereof can also be used.

These organic pigments and dyes can be used alone or in combination of two or more as desired. The amount of the pigment added is 2 to 20% by mass with respect to the polymer,
Preferably 3 to 15 mass% is selected.

The colorant may be used after surface modification. As the surface modifier, conventionally known ones can be used, and specifically, a silane coupling agent, a titanium coupling agent, an aluminum coupling agent and the like can be preferably used.

<Manufacturing Step> In the manufacturing step of the polymerized toner of the present invention, a step of dispersing a monomer solution in which a releasing agent is dissolved in an aqueous medium, and then preparing resin particles containing the releasing agent by a polymerization method, A step of fusing the resin particles in an aqueous medium using the resin particle dispersion, a washing step of removing the obtained particles by filtering the obtained particles from the aqueous medium, a step of drying the obtained particles, Further, it is composed of an external additive adding step of adding an external additive and the like to the particles obtained by further drying. Here, the resin particles may be colored particles. In addition, non-colored particles can also be used as the resin particles. In this case, the colored particles are obtained by adding the colorant particle dispersion liquid or the like to the dispersion liquid of the resin particles and then fusing in an aqueous medium. You can

Particularly, as the fusion method, a method of salting out / fusing by using the resin particles produced in the polymerization step is preferable. When non-colored resin particles are used, the resin particles and the colorant particles can be salted out / fused in an aqueous medium.

The term "salting out / fusion" means that aggregation and fusion due to salting out proceed in parallel. Fusing means a state in which the interface between resin particles disappears. For details, see JP 2
No. 000-292973.

Further, not only the colorant and the release agent, but also the charge control agent which is a constituent element of the toner can be added as particles in this step.

Here, the aqueous medium means that the main component is water, and the water content is 50% by mass or more. Examples of substances other than water include organic solvents that dissolve in water, such as methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, and tetrahydrofuran. It is preferably an organic solvent that does not dissolve the resin,
Alcohol-based organic solvents such as methanol, ethanol, isopropanol and butanol are particularly preferable.

As a preferred polymerization method in the present invention, a monomer solution in which a releasing agent is dissolved in a monomer is dispersed by mechanical energy in a water-based medium in which a surfactant having a concentration below the critical micelle concentration is dispersed by mechanical energy. A method in which a water-soluble polymerization initiator is added to the dispersion to carry out radical polymerization can be mentioned. In this case, an oil-soluble polymerization initiator may be added to the monomer before use.

The disperser for dispersing the oil droplets is not particularly limited, and examples thereof include Clearmix, an ultrasonic disperser, a mechanical homogenizer, a Manton-Gaulin, a pressure homogenizer and the like.

The colorant particles may be prepared by dispersing the colorant in an aqueous medium. This dispersion is carried out in water with the surfactant concentration above the critical micelle concentration (CMC).

The dispersing machine at the time of dispersing the pigment is not particularly limited, but preferably Clearmix, an ultrasonic dispersing machine, a mechanical homogenizer, a pressure dispersing machine such as Manton-Gorin or a pressure homogenizer, a sand grinder, a Getzmann mill or a diamond fine mill. And the like medium-type dispersers.

The above-mentioned surfactant can be used as the surfactant used here. [Salting-out / fusion step] In the salting-out / fusion step, the salting-out agent is added as a flocculant having a critical flocculation concentration or higher to the water in which the resin particles and the colorant particles are present, and then the resin particles are added. By heating above the glass transition point of (1), salting out proceeds and at the same time fusion is performed.

Here, the salting-out agent is lithium, potassium,
Examples thereof include sodium, magnesium, calcium, strontium, barium, aluminum and titanium, preferably potassium, sodium, magnesium, calcium, barium chloride, bromine, iodine, carbonate and sulfate.

When the fusion of the present invention is carried out by salting out / fusion, the time after the salting out agent is added and allowed to stand is controlled while monitoring the shape factor, but it is preferably as short as possible. The temperature at which the salting-out agent is added is not particularly limited, but is preferably 30 ° C to 90 ° C.

Further, in the present invention, it is preferable to use a method of raising the temperature of the dispersion liquid of the resin particles as quickly as possible and heating it to the glass transition temperature of the resin particles or higher. The time required to raise the temperature is less than 30 minutes, preferably less than 10 minutes. Further, although it is necessary to raise the temperature quickly, the rate of temperature increase is preferably 1 ° C./minute or more. Although the upper limit is not particularly clear, it is preferably 15 ° C./min or less from the viewpoint of suppressing the generation of coarse particles due to the rapid progress of salting out / fusion. As a particularly preferable form, a method of continuously advancing salting out / fusion even at the time of reaching the glass transition temperature or higher can be mentioned. By using this method, fusion can be effectively progressed with the growth of particles,
The particle strength of the final toner can be increased and the durability can be improved.

The toner of the present invention preferably contains a release agent in its particles. By using a toner obtained by salting out / fusing resin particles containing a release agent, the release agent can be uniformly included in the toner particles, and the release agent is included even in the vicinity of the surface. The formed toner can be formed.

By thus salting out / fusing the resin particles in which the release agent is included in the resin particles with the colorant particles in the aqueous medium, a toner in which the release agent is finely dispersed is obtained. You can

As the release agent, compounds represented by the following general formula are preferred. R ^1- (OCO-R ² ) _n n is an integer of 1 to 4, preferably 2 to 4, more preferably 3 to 4, and particularly preferably 4.

R ¹ and R ² represent a hydrocarbon group which may have a substituent. R ¹ preferably has 1 to 40 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 2 carbon atoms.
~ 5.

R ² preferably has 1 to 40 carbon atoms, more preferably 16 to 30 carbon atoms, and particularly preferably 18 to 26 carbon atoms.

Next, typical exemplified compounds will be described.

[0096]

[Chemical 1]

[0097]

[Chemical 2]

The addition amount is 1% by mass to 3% based on the total amount of the toner.
0% by mass is preferable, and more preferably 3% by mass to 25%.
It is% by mass.

In addition to the colorant and the release agent, the toner may be added with a material capable of imparting various functions as a toner material. Specific examples include charge control agents. These components can be added by various methods such as a method of adding the components in the above-mentioned salting-out / fusing step, a method of incorporating them in the toner, a method of adding them to the resin particles themselves.

Similarly, various charge control agents are known,
Moreover, the thing which can be disperse | distributed in water can be used. Specific examples thereof include a quaternary ammonium salt compound, a fluorine compound, an azo metal complex, a salicylic acid metal salt, or a metal complex thereof.

<< External Additive >> The toner of the present invention has a fluidity,
A so-called external additive may be added and used for the purpose of improving charging property and cleaning property.
These external additives are not particularly limited, and various inorganic fine particles, organic fine particles and lubricants can be used.

As the inorganic fine particles, conventionally known ones can be used. Specifically, silica, titanium, alumina fine particles and the like can be preferably used. The inorganic fine particles are preferably hydrophobic. Specifically, as the silica fine particles, for example, commercially available products R-805, R-976, R-974, and R-97 manufactured by Nippon Aerosil Co., Ltd.
2, R-812, R-809, Hovst HVK-
2150, H-200, commercial product TS- manufactured by Cabot Corporation
720, TS-530, TS-610, H-5, MS-
5 and the like.

Examples of titanium fine particles include commercial products T-805 and T-604 manufactured by Nippon Aerosil Co., Ltd., and commercial products MT-100S, MT-100B and MT-5 manufactured by Teika.
00BS, MT-600, MT-600SS, JA-
1. Commercial products TA-300SI and TA- manufactured by Fuji Titanium Co., Ltd.
500, TAF-130, TAF-510, TAF-5
10T, commercial products IT-S, IT-OA manufactured by Idemitsu Kosan Co., Ltd.
IT-OB, IT-OC, etc. are mentioned.

Examples of the alumina fine particles include commercial products RFY-C and C-604 manufactured by Nippon Aerosil Co., Ltd., and commercial product TTO-55 manufactured by Ishihara Sangyo Co., Ltd.

As the organic fine particles, spherical organic fine particles having a number average primary particle diameter of about 10 to 2000 nm can be used. As this, a homopolymer such as styrene or methyl methacrylate or a copolymer thereof can be used.

Examples of the lubricant include zinc stearate, aluminum, copper, magnesium and calcium salts, oleic acid zinc, manganese, iron, copper and magnesium salts, and palmitic acid zinc, copper, magnesium and calcium. And the like, salts of zinc and calcium of linoleic acid, and metal salts of higher fatty acids such as salts of zinc and calcium of ricinoleic acid.

The addition amount of these external additives is preferably 0.1 to 5% by mass with respect to the toner. As a method of adding the external additive, various known mixing devices such as a Turbuler mixer, a Henschel mixer, a Nauter mixer, and a V-type mixer can be used.

<< Developer >> The toner of the present invention may be used as a one-component developer or a two-component developer.

When used as a one-component developer, it may be a non-magnetic or magnetic one-component developer.

Further, it can be used as a two-component developer by mixing with a carrier. In this case, conventionally known materials such as metals such as iron, ferrite and magnetite and alloys of these metals with metals such as aluminum and lead can be used as the magnetic particles of the carrier. Ferrite particles are particularly preferable. The volume average particle diameter of the magnetic particles is preferably 15 to 100 μm, more preferably 25 to 80 μm.

The volume average particle diameter of the carrier is typically measured by a laser diffraction type particle size distribution measuring apparatus "HELOS" equipped with a wet disperser (SYMPATIC (SYMP).
(Made by ATEC)).

The carrier is preferably one in which magnetic particles are further coated with a resin, or a so-called resin dispersion type carrier in which magnetic particles are dispersed in a resin. The resin composition for coating is not particularly limited, but, for example, an olefin resin, a styrene resin, a styrene-acrylic resin, a silicone resin, an ester resin, a fluorine-containing polymer resin, or the like is used. The resin for forming the resin-dispersed carrier is not particularly limited, and known ones can be used. For example, styrene-acrylic resin, polyester resin, fluorine resin, phenol resin, etc. are used. be able to.

The toner of the present invention is fixed by an image forming method and an image forming apparatus including a fixing step by a heat fixing device.

An example of the image forming method and the image forming apparatus of the present invention will be described first. FIG. 1 is a schematic configuration diagram of an image forming apparatus showing an embodiment of the present invention. Reference numeral 4 denotes a photoconductor, which is a typical example of the electrostatic latent image forming member in the present invention.
An organic photoconductor (OPC), which is a photosensitive layer, is formed on the outer peripheral surface of an aluminum drum base, and rotates in the direction of the arrow at a predetermined speed. In this embodiment, the photoconductor 4 has an outer diameter of 60 mm.

In FIG. 1, exposure light is emitted from the semiconductor laser light source 1 based on the information read by a document reading device (not shown). This is distributed by the polygon mirror 2 in the direction perpendicular to the paper surface of FIG. 1, and is irradiated onto the surface of the photoconductor through the fθ lens 3 that corrects the image distortion to form an electrostatic charge latent image. The photoconductor is previously uniformly charged by the charger 5, and starts rotating clockwise in accordance with the timing of image exposure.

The electrostatic latent image on the surface of the photoconductor is developed by the developing device 6, and the formed developed image is transferred by the transfer device 7 to the recording material 8 which is conveyed at a timing. Further, the photoconductor 4 and the transfer material 8 are separated by a separator (separation pole) 9
The toner development image is transferred and carried on the transfer material 8 and guided to the fixing device 10 to be fixed.

The untransferred toner and the like remaining on the surface of the photoconductor are
It is cleaned by a cleaning device 11 of a cleaning blade type, the residual charge is removed by pre-charge exposure (PCL) 12, and it is uniformly charged again by the charging device 5 for the next image formation.

The transfer material is typically plain paper,
There is no particular limitation as long as it can transfer an unfixed image after development, and of course, a PET base for OHP and the like are included.

The cleaning blade 13 has a thickness of 1
A rubber-like elastic body of about 30 mm is used, and urethane rubber is most often used as the material. Since this is used in pressure contact with the photoconductor, heat is easily transmitted, and it is desirable to keep it away from the photoconductor when the image forming operation is not performed.

In recent years, in the field of electrophotography in which an electrostatic latent image is formed on a photoreceptor and the latent image is developed to obtain a visible image, it is easy to improve the image quality, convert it, edit it, etc., and obtain a high quality image. Research and development of an image forming method using a digital method capable of forming an image are actively performed.

As a scanning optical system that is optically modulated by a digital image signal from a computer or a copy manuscript adopted in this image forming method and apparatus, an acousto-optic modulator is interposed in a laser optical system, and the acousto-optic modulator is used to emit light. There are a device for modulating and a device for directly modulating the laser intensity by using a semiconductor laser. A spot-like image is formed by spot exposure on the uniformly charged photoconductor from these scanning optical systems.

The beam emitted from the above-mentioned scanning optical system has a circular or elliptical luminance distribution which has a hem spread to the left and right and approximates a normal distribution. For example, in the case of a laser beam, it is usually the main component on the photosensitive member. One or both of the scanning direction and the sub-scanning direction is a very small circle or ellipse of 20 to 100 μm.

Further, the image forming apparatus may be configured such that the photosensitive member 4 and the process cartridge including at least one of the charging device 5, the developing device 6, the cleaning device 11 and the transfer device 7 are mounted.

[0124]

The present invention will be described below with reference to examples.
Aspects of the invention are not limited to these. In addition, "part" in a sentence represents a "mass part."

<< Production Example of Resin Particles for Toner >> [Latex (1HML)] (1) Preparation of Core Particles (First Stage Polymerization) A 5000 ml separable reactor equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introducing device. 7.08 g of the following anionic surfactant (101) C ₁₀ H ₂₁ (OCH ₂ CH ₂ ) ₂ OSO ₃ Na was placed in a flask, and a surfactant solution (aqueous medium) dissolved in 3010 g of ion-exchanged water was charged, Under nitrogen stream 2
The temperature inside the flask was raised to 80 ° C. while stirring at a stirring speed of 30 rpm.

To this surfactant solution, 9.2 g of a polymerization initiator (potassium persulfate: KPS) was added 200 g of ion-exchanged water.
Was added to the solution of the initiator, and the temperature was adjusted to 75 ° C. Then, 70.1 g of styrene and 1 of n-butyl acrylate were added.
A monomer mixture liquid consisting of 9.9 g and methacrylic acid 10.9 g was added dropwise over 1 hour, and this system was heated and stirred at 75 ° C. for 2 hours to perform polymerization (first-stage polymerization), A latex (dispersion of resin particles composed of a high molecular weight resin) was prepared. This is designated as "latex (1H)".

(2) Formation of Intermediate Layer (Second Stage Polymerization) In a flask equipped with a stirrer, styrene 1
Into a monomer mixture consisting of 05.6 g, 30.0 g of n-butyl acrylate, 6.2 g of methacrylic acid and 5.6 g of n-octyl-3-mercaptopropionic acid ester, the above compound 19) was used as a release agent. It is referred to as a represented compound (hereinafter, "Exemplified Compound 19)". ) 98.0 g was added, and the mixture was heated to 90 ° C. and dissolved to prepare a monomer solution.

On the other hand, an anionic surfactant (see the above (10
1)) A surfactant solution prepared by dissolving 1.6 g in 2700 ml of ion-exchanged water is heated to 98 ° C., and the latex (1H), which is a dispersion liquid of core particles, is converted into a solid content in the surfactant solution. After 28 g was added, a monomer solution of the above-exemplified compound 19 was mixed and dispersed for 8 hours by a mechanical disperser having a circulation path "CLEARMIX" (manufactured by M-Technique Co., Ltd.) to obtain emulsified particles (oil). Drops) were prepared.

Then, a polymerization initiator (KP
S) Add an initiator solution prepared by dissolving 5.1 g of deionized water in 240 ml and deionized water of 750 ml. Polymerization (second-stage polymerization) is performed by heating and stirring this system at 98 ° C. for 12 hours to obtain a latex (composite resin particles having a structure in which the surface of resin particles made of a high molecular weight resin is coated with an intermediate molecular weight resin). A dispersion) was obtained. This is designated as "latex (1HM)".

(3) Formation of Outer Layer (Third Stage Polymerization) In the latex (1HM) obtained as described above, 7.4 g of a polymerization initiator (KPS) was dissolved in 200 ml of ion-exchanged water to prepare an initiator solution. Was added. Under the temperature condition of 80 ° C., 300 g of styrene and 95 of n-butyl acrylate
g, 15.3 g of methacrylic acid, and 10.4 g of n-octyl-3-mercaptopropionic acid ester were added dropwise over 1 hour. After completion of the dropping, polymerization (third stage polymerization) was carried out by heating and stirring for 2 hours, followed by cooling to 28 ° C. and latex (a central part made of a high molecular weight resin, an intermediate layer made of an intermediate molecular weight resin, and a low layer). A dispersion liquid of composite resin particles having an outer layer made of a molecular weight resin and containing the exemplified compound 19) in the intermediate layer was obtained. This latex is referred to as "latex (1HML)".

The composite resin particles constituting this latex (1HML) are 138,000, 80,000 and 1
Has a peak molecular weight of 3,000, and
The weight average particle diameter of the composite resin particles was 122 nm.

[Latex (2HML)] Instead of the anionic surfactant (101), an anionic surfactant (sodium dodecylbenzenesulfonate: SDS)
Latex (1 HM) except that 7.08 g was used.
In the same manner as in L), a latex (dispersion liquid of composite resin particles having a central portion made of a high molecular weight resin, an intermediate layer made of an intermediate molecular weight resin, and an outer layer made of a low molecular weight resin) was obtained. This latex is referred to as "latex (2HML)".

The composite resin particles constituting this latex (2HML) are 138,000, 80,000 and 1
It has a peak molecular weight of 2,000, and
The weight average particle diameter of the composite resin particles was 110 nm.

<< Production Example of Toner >> [Production of Toner 1] Anionic surfactant (101) 5
9.0 g of ion-exchanged water was dissolved in 1600 ml with stirring, and while stirring this solution, carbon black "Regal 3
30 "(manufactured by Cabot Co.) 420.0 g is gradually added, and then dispersion treatment is performed using" CLEARMIX "(manufactured by M-Technique Co., Ltd.) to obtain a dispersion liquid of colorant particles (hereinafter referred to as" colorant dispersion liquid "). 1 ”.) Was prepared.
The particle size of the colorant particles in this colorant dispersion was measured by an electrophoretic light scattering photometer "ELS-800" (manufactured by Otsuka Electronics Co., Ltd.).
It was 89 nm as a weight average particle diameter.

420.7 g of latex (1HML) (as solid content), 900 g of ion-exchanged water, and 1166 g of colorant dispersion 1 were placed in a reaction container (a temperature sensor, a cooling pipe, a nitrogen introducing device, and a stirring device). (Four-necked flask)
And stirred. After adjusting the temperature in the container to 30 ℃,
The pH of the solution was adjusted to 9.0 by adding 5 mol / 1000 ml of a sodium hydroxide aqueous solution.

Then, magnesium chloride hexahydrate 1
An aqueous solution prepared by dissolving 2.1 g in 1000 ml of ion-exchanged water was added with stirring at 30 ° C. for 10 minutes. Next, after standing for 3 minutes, the temperature rise was started and the temperature of this system was raised to 96 ° C. over 3 minutes to generate salting out / fused particles. In that state, the FP connected in-line to the reaction vessel
The equivalent circle diameter, circularity, and particle diameter of the particles were measured by IA-2000, and when the predetermined values were reached, sodium chloride 2
An aqueous solution in which g was dissolved in 1000 ml of ion-exchanged water was added to suppress grain growth, and then 0.2 to 1.0 μm was grown to adjust the inclination of circularity with respect to the equivalent circle diameter.

Then, the mixture was cooled to 30 ° C., pH was adjusted to 2.0 by adding hydrochloric acid, and stirring was stopped. The salted-out / fused particles produced were filtered and washed repeatedly with ion-exchanged water at 45 ° C. Then, it was dried with warm air at 40 ° C., 0.8 parts by mass of hydrophobic silica and 1.0 part by mass of hydrophobic titanium oxide were added, and the peripheral speed of the rotary blade of a 10,000 ml Henschel mixer was set to 30 m / s. After setting and mixing for 25 minutes, Toner 1 was obtained.

[Production of Toners 2 to 5] In production of Toner 1, latex (2HML) was used in place of latex (1HML). When salting out / fusing particles produced a circle equivalent diameter of 2.5 μm and a circularity of 0.987 in the production of salting out / fusing particles, an aqueous solution prepared by dissolving 8 g of sodium chloride in 1000 ml of ion-exchanged water was added. To stop grain growth. Liquid temperature 90 ° C for further aging treatment
By heating and stirring for 20 minutes, the fusion of particles was continued and a dispersion liquid of colored particles was obtained. The obtained dispersion liquid of colored particles is referred to as a dispersion liquid S of colored particles. On the other hand, in the formation of associated particles, when the equivalent circle diameter of the associated particles reached 7.8 μm and the circularity reached 0.875, 80 g of sodium chloride was added.
Was added to an aqueous solution of 1000 ml of ion-exchanged water to stop the particle growth, and the same treatment was carried out to obtain a colored particle dispersion L. Next, the colored particle dispersion S and the colored particle dispersion L are mixed by FPIA-2000 while monitoring the equivalent circle diameter, the circularity, and the particle diameter of the particles, and when the predetermined values are reached, the mixture is cooled to 30 ° C. And add hydrochloric acid to adjust the pH
Was adjusted to 2.0 and stirring was stopped. The associated particles produced were filtered, washed repeatedly with ion-exchanged water at 45 ° C., then dried with warm air at 40 ° C., and the hydrophobic silica 0.
Add 8 parts by mass and 1.0 part by mass of hydrophobic titanium oxide,
Toner 2 shown in Table 1 was prepared by setting the peripheral speed of a rotary blade of a Henschel mixer of 30,000 ml to 30 m / s and mixing for 25 minutes.
~ 5 was obtained.

[Production of Toner 1 for Comparison] Latex (1
HML) 420.7 g (in terms of solid content), ion-exchanged water 900 g, and colorant dispersion 1 166 g, a reaction container (four-necked flask) equipped with a temperature sensor, a cooling pipe, a nitrogen introducing device, and a stirring device. ) And stirred. After adjusting the temperature in the container to 30 ° C, add 5 mol / 1000 to this solution.
The pH was adjusted to 9.5 by adding ml of a sodium hydroxide aqueous solution.

Then, magnesium chloride hexahydrate 1
An aqueous solution prepared by dissolving 2.1 g in 1000 ml of ion-exchanged water was added with stirring at 30 ° C. for 10 minutes. Next, after standing for 3 minutes, the temperature rise was started and the temperature of this system was raised to 90 ° C. over 60 minutes to generate associated particles. When the equivalent circle diameter reaches 3.5 μm, sodium chloride 8
An aqueous solution in which 0.4 g was dissolved in 1000 ml of ion-exchanged water was added to stop grain growth. Further, as an aging treatment, the mixture was heated and stirred at a liquid temperature of 98 ° C. for 12 hours.

Then, the mixture was cooled to 30 ° C., pH was adjusted to 2.0 by adding hydrochloric acid, and stirring was stopped. The formed associated particles were filtered and repeatedly washed with ion exchanged water at 45 ° C. Then, it was dried with warm air at 40 ° C., 0.8 parts by mass of hydrophobic silica and 1.0 part by mass of hydrophobic titanium oxide were added, and the peripheral speed of the rotary blade of a 10,000 ml Henschel mixer was set to 30 m / s. After setting and mixing for 25 minutes, Comparative Toner 1 was obtained.

Next, as in the case of producing the toners 2 to 5, the mixing ratio of the colored particle dispersions S and L is adjusted, and the comparative toners 2 to 2 are prepared.
4 was produced.

As described above, the average value of the circularity of the prepared toners 1 to 5 and the comparative toners 1 to 4, the average value of the equivalent circle diameters, the value of the inclination of the circularity with respect to the equivalent circle diameters, the BET specific surface area, ES
Table 1 shows the surface abundance of silicon atoms and the abundance of carbon atoms measured by CA.

[0144]

[Table 1]

<< Manufacture of Carrier >> Manufacture of Ferrite Core Material 18 mol% MnO, 4 mol% MgO, Fe ₂ O ₃
78 mol% was pulverized with a wet ball mill for 2 hours, mixed and dried, and then temporarily calcined by holding at 900 ° C. for 2 hours, and this was pulverized with a ball mill for 3 hours to form a slurry. A dispersant and a binder were added, the mixture was granulated by a spray dryer, dried, and then main-baked at 1200 ° C. for 3 hours to obtain ferrite core material particles having a resistance value of 4.3 × 10 ⁸ Ω · cm.

(Production of coating resin) First, cyclohexyl was prepared by an emulsion polymerization method in which sodium benzenesulfonate having an alkyl group having 12 carbon atoms was used as a surfactant and the concentration was 0.3% by mass in an aqueous medium. A copolymer of methacrylate / methyl methacrylate (copolymerization ratio 5/5) was synthesized, and the volume average primary particle diameter was 0.1 μmm, the weight average molecular weight (Mw) was 200,000, and the number average molecular weight was (M).
n) 91,000, Mw / Mn = 2.2, softening point temperature (Tsp) 230 ° C. and glass transition temperature (Tg) 11
Resin fine particles at 0 ° C. were obtained. In the emulsified state, the resin fine particles azeotrope with water, and the residual monomer amount becomes 510
It was defined as ppm.

Next, 100 parts by mass of the ferrite core material particles and 2 parts by mass of the resin fine particles are charged into a high speed stirring mixer equipped with stirring blades and stirred and mixed at 120 ° C. for 30 minutes to utilize the action of mechanical impact force. Thus, a resin-coated carrier having a volume average particle diameter of 61 μm was obtained.

<< Production of Developer >> Each of the colored particles added with the external additive and the carrier were mixed to prepare a developer having a toner concentration of 6% by mass.

<< Production of Photoreceptor P1 >> The following coating solution was applied onto a cylindrical conductive support having a length of 380 mm and a diameter of 60 mm.

<Undercoat layer> Titanium chelate compound (TC-750, manufactured by Matsumoto Pharmaceutical Co., Ltd.) 30 g Silane coupling agent (KBM-503, manufactured by Shin-Etsu Chemical Co., Ltd.) 17 g 2-propanol 150 ml Cylindrical conductive support using the above coating liquid A film thickness of 0.
It was applied so as to have a thickness of 5 μm.

<Charge Generation Layer> Y-type titanyl phthalocyanine (titanyl phthalocyanine having a maximum peak at 27.2 ° of Bragg angle 2θ (± 0.2 °) in Cu-Kα characteristic X-ray diffraction spectrum measurement) 60 g Silicone modified Butyral resin (X-40-1211M: manufactured by Shin-Etsu Chemical Co., Ltd.) 700 g 2-butanone 2000 ml was mixed and dispersed for 10 hours using a sand mill to prepare a charge generation layer coating solution.

This coating solution was applied on the undercoat layer by a dip coating method to form a charge generation layer having a thickness of 0.2 μm.

<Charge Transport Layer> Charge Transport Material N- (4-methylphenyl) -N- {4- (β-phenylstyryl) phenyl} -p-toluidine 225 g Polycarbonate (viscosity average molecular weight 30,000) 300 g Antioxidant Agent (Exemplified compound 1-3) 6 g Dichloromethane 2000 ml was mixed and dissolved to prepare a charge transport layer coating solution. This coating solution was applied onto the charge generation layer by a dip coating method to form a charge transport layer having a dry film thickness of 20 μm.

<Protective Layer> Methyltrimethoxysilane 150 g Dimethyldimethoxysilane 30 g Reactive charge transporting compound 15 g Polyvinylidene fluoride particles (volume average particle diameter 0.2 μm) 10 g Antioxidant 0.75 g 2-Propanol 75 g 3% acetic acid 5 g was mixed to prepare a coating liquid for the resin layer. A resin layer having a thickness of 2 μm is formed on the charge transport layer by a circular amount regulation type coating device on the charge transport layer, and the resin layer is heated and cured at 120 ° C. for 1 hour to form a siloxane resin layer. It was made.

As an evaluation machine, a photoconductor P1 and each developing device are installed in a digital copying machine (corona charging, laser exposure, reversal development, electrostatic transfer, nail separation, cleaning blade) having the image forming process shown in FIG. The agent was mounted and evaluated. The above digital copying machine was evaluated under the following conditions. The digital copying machine employs a toner recycling method in which the toner collected by the cleaning blade is returned to the developing device and reused.

Charging conditions Charging device: Scorotron charger, initial charging potential of -750
V exposure condition Set the exposure amount to make the exposed portion potential -50V.

Development conditions DC bias; -550V transfer pole; corona charging system Further, as a fixing device, iron was used as a core metal, and the surface was made of PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) having a thickness of 25 μm. ) Using a heating roller having a surface roughness Ra of 0.8 μm,
An iron cored bar was used as the pressure roller, and a pressure roller having a surface roughness Ra of 0.8 μm was used in which a 120 μm thick PFA tube was coated on the HTV silicone rubber.
The nip width is 3.8 mm and the linear velocity is 420 mm.
/ Sec.

The fixing device cleaning mechanism and the silicone oil supply mechanism are not mounted. The fixing temperature was set at 165 ° C. by controlling the surface temperature of the heating roller.

The copying conditions are low temperature and low humidity environment (10 ° C., 20 ° C.).
% RH), 1 million continuous copies were made, and the following evaluation criteria were used to evaluate the offset resistance of the copied images, stains during image formation, standard glossiness, cleaning properties, and filming of the photoconductor.

The evaluation was performed by copying an original image in which a character image with a pixel ratio of 7%, a human face photograph image, a solid white image, and a solid black image were equally divided into quarters on A4 neutral paper.
The halftone, solid white image, solid black image, and fine line image were evaluated for every 10,000 sheets.

<< Uniformity of Halftone >> Continuous 10
The uniformity of the halftone image due to the transferability variation after the copying of 0,000 copies was evaluated.

The ranks are divided into the following and the evaluations are shown. ◎: Uniform image without unevenness ○: Extremely thin stripe-like unevenness is present △: There are several thin stripe-like unevennesses, but there is no problem in practical use ×: Several clear stripes-like unevenness are present Evaluation rank A to C were passed and D was rejected.

<< Reproducibility of halftone dots >> A 10% halftone dot image is formed on the entire surface of the image, and dust around the dots is visually observed with a loupe.
The rank was evaluated as follows.

A: Almost no dust can be detected B: There is a slight amount of dust, but it is not noticeable unless one looks carefully C: There is a little dust D: Dust can be clearly detected In the present invention, A to C are acceptable. And D fails.

<< Selective developing property >> After continuous 10,000 copies, the toner in the developing device is collected, and the circularity of the collected toner is determined by FP.
It was measured by IA-2000 (manufactured by Sysmec Corporation). d
_{When 90} / d ₁₀ is 4.5 or more, toner scattering is remarkable and stains inside the machine become noticeable.

<< Selective Transferability >> The toner collected by the cleaning blade is returned to the developing device for every 10,000 copies. The transfer residual toner in the toner recycling device is collected, and the circularity of the collected toner is calculated by FPIA-2000 (Sysmec Corporation). The residual number of transfer residual toner was evaluated by the number of sheets where d ₉₀ / d ₁₀ was 4.5 or more. Similar to the above-mentioned selective developability, d ₉₀ /
When d ₁₀ is 4.5 or more, toner scattering is remarkable and stains inside the machine become noticeable.

The toner filming on the photosensitive member and the toner filming on the developing roller are the results of observing the surface of the photosensitive member and the surface of the developing roller with the naked eye after every 10,000 copies.

[0168]

[Table 2]

As is clear from Table 2, Examples 1 to 5 in the present invention showed good characteristics in each item, but Comparative Examples 1 to 4 outside the present invention had problems.

[0170]

EFFECTS OF THE INVENTION According to the present invention, transfer dust, which occurs when the particle size and shape of toner particles are made uniform, is reduced, halftone uniformity is good, and halftone reproducibility is excellent. A toner for developing a latent charge image, and an image forming method and an image forming apparatus using the toner can be provided.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an example of an image forming method and an image forming apparatus of the present invention.

[Explanation of symbols]

1 Semiconductor laser light source 2 polygon mirror 3 fθ lens 4 Electrostatic latent image forming body (photoreceptor) 5 charger 6 developer 7 Transfer device 8 recording materials 9 separation poles 10 Fixing device

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroshi Yamazaki             2970 Ishikawa-cho, Hachioji-shi, Tokyo Konica stock             In the company F-term (reference) 2H005 AA15 AB03 AB06 EA05 EA07                       EA10 FA01 FB01

Claims (9)

[Claims] 1. An average value of circularity is 0.94 to 0.98, and an average value of equivalent circle diameters is 2.6 μm to 7.4 μm.
And the slope of the circularity with respect to the equivalent circle diameter is -0.050.
A toner for developing an electrostatic latent image, characterized in that the toner is from -0.010. 2. The average value of equivalent circle diameters is 3.4 μm to 6.6.
μm, the slope of the circularity with respect to the equivalent circle diameter is -0.0
The toner for developing an electrostatic latent image according to claim 1, wherein the toner is 40 to -0.020. 3. A ratio of a circle equivalent diameter d ₁₀ at a cumulative ₁₀ % and a circle equivalent diameter d ₉₀ at a cumulative 90%, d ₉₀ / d ₁₀ is 1.
The toner for developing an electrostatic latent image according to claim 1, wherein the toner has a particle size of 2 to 2.0. 4. The toner for developing an electrostatic latent image according to claim 1, which is obtained by polymerizing at least a polymerizable monomer in an aqueous medium. 5. The toner for developing an electrostatic latent image according to claim 1, which is obtained by salting out / fusing at least resin particles in an aqueous medium. 6. A BET specific surface area of 1.1 m ² / g to 4.
0 m ² / g, the surface abundance of silicon atoms measured by ESCA is 6 area% to 12 area%, and the abundance of carbon atoms is 50 area% to 75 area%. The toner for developing an electrostatic latent image according to any one of items. 7. An image forming method comprising a step of visualizing an electrostatic latent image formed on a photoreceptor to a visible image, transferring the visible image onto recording paper, and heating and fixing the visible image. 5. An image forming method, which is carried out using the electrostatic latent image developing toner according to any one of 5 above. 8. The image forming method according to claim 7,
An image forming apparatus characterized in that the photosensitive member is irradiated by digital exposure. 9. A two-component developer comprising a mixture of the electrostatic latent image developing toner according to claim 1 and a magnetic carrier.