JP2000338709A - Electrostatic charge image developing toner, its production and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a stable image over a long period of time in various environments such as environments at high temperature and high humidity and at low temperature and low humidity by allowing a toner having a specified shape to exist selectively. SOLUTION: The electrostatic charge image developing toner consists essentially of a resin and a colorant and includes 1-50 number % toner having 3-9 μm volume average particle diameter and a major axis size to minor axis size ratio (X/Y) of 1.2-3.0. This toner has an amorphous shape close to a elliptical shape, hardly under goes a shape change due to stress even after long-term use and maintains cleanability over a long period of time. The toner is formed by gradually increasing the molecular weight of oil droplets present in an aqueous medium in a suspended state by the progress of polymerization until they become soft particles and promoting the uniting of the particles by the collision of the particles to form the toner having thin particles in the shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a toner for developing an electrostatic image used in a copying machine, a printer, and the like, a method for producing the same, and an image forming method.

[0002]

2. Description of the Related Art In recent years, the electrophotographic development system has been used in various fields. For example, it is used not only in monochrome copying machines but also in fields such as printers that are output terminals of computers, color copying machines, color printers, and the like. As these applications have advanced, demands on image quality have increased.

There are various proposals for improving the image quality by reducing the particle size of the toner in order to improve the image quality, and there are no shortfalls in the list. A so-called polymerization toner is known as a technique for coping with the reduction in particle diameter. Japanese Patent Application Laid-Open No.
A method of preparing by a suspension polymerization method as shown in JP-A-130762, a method of producing a polymerization toner in which resin particles and colorant particles are associated with each other as described in JP-A-63-186253, and the like. Are known.

[0004] The small particle size toner is useful in that the resolution can be increased and the image quality is improved. However, since the small particle size increases the adhesion to the photoreceptor, There is a problem that a load in a cleaning process for removing untransferred toner from the photoconductor is increased.

That is, in order to remove toner having high adhesion to the photoreceptor, it is necessary to improve the cleaning force. In brush cleaning, the brush pressure must be increased, and in blade cleaning, the blade pressing force must be increased. It is necessary to do. When this method is employed, the cleaning itself is improved, but the pressing force against the photoreceptor increases the rubbing force, so that the photoreceptor wears out sharply. And stable images cannot be formed over a long period of time. Further, in blade cleaning using a high pressing force, toner slip-through, fusion and the like are likely to occur due to deformation of the blade and the like, which tends to cause a problem of causing image defects.

Further, in a low-temperature and low-humidity environment, the electrostatic adhesion increases, so that it is necessary to increase the cleaning pressure. As a result, the wear of the photosensitive member and the abrasion of the cleaning blade are promoted, and the defective cleaning is likely to occur. Tend to be. Also, in high temperature and high humidity environments, the frictional heat between the photoreceptor and the blade tends to increase, and when small toner particles are used, problems such as fusion to the blade and filming on the photoreceptor occur. It's easy to do.

As described above, various problems are involved in the practical use of a toner having a small particle diameter at present.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to develop a small particle size electrostatic image capable of forming a stable image over a long period of time even in various environments such as high temperature, high humidity and low temperature and low humidity. An object of the present invention is to provide a toner, a method of manufacturing the same, and an image forming method.

[0009]

Means for Solving the Problems As a result of intensive studies, the inventors have selected not only a toner having a small particle size but also a toner having a specific shape in order to meet the demand for higher resolution of an image. It has been found that stabilization of an image over a long period of time can be achieved by the presence of the present invention, and the present invention has been completed.

The object of the present invention is attained by adopting one of the following constitutions.

[1] In a toner for developing an electrostatic image comprising at least a resin and a colorant, the volume average particle diameter of the toner is 3 to 9 μm, and the major axis (X) and the minor axis (Y) of the toner Wherein the ratio (X / Y) of the toner is 1.2 to 3.0, and 1 to 50% by number of the toner.

[2] The toner for developing an electrostatic charge image according to [1], wherein the toner has an arithmetic mean value of a shape factor represented by the following formula of 1.3 or more.

Shape factor = ((maximum diameter / 2) ² × π) / projected area [3] In the toner of [1], the toner is a toner obtained by associating at least resin particles in an aqueous medium. A toner for developing electrostatic images, characterized by the following.

[4] The toner for developing an electrostatic image according to [1], wherein the toner is obtained by polymerizing at least a polymerizable monomer in an aqueous medium.

[5] In an image forming method in which an electrostatic latent image formed on a photoreceptor is brought into contact with a developer layer formed on a developer carrying member to visualize the image, the developer may have a volume average An electrostatic image developing toner having a particle size of 3 to 9 μm, wherein the ratio (X / Y) of the major axis (X) to the minor axis (Y) of the toner is 1.2 to
An image forming method, wherein 3.0 to 50% by number of toner is used.

[6] The electrostatic latent image formed on the photoreceptor is opposed to the developer layer formed on the developer carrying member in a non-contact state, and only the toner for developing an electrostatic charge image is made to fly and observed. In the image forming method for forming an image, the developer is a toner for developing an electrostatic charge image having a volume average particle diameter of 3 to 9 μm, and the ratio (X / Y) is 1.2-
An image forming method, wherein 3.0 to 50% by number of toner is used.

[7] An image forming method for developing an electrostatic latent image formed on a photoreceptor with a developer containing a toner, transferring the electrostatic latent image to an image support, and cleaning the toner remaining on the photoreceptor. The developer is an electrostatic image developing toner having a volume average particle diameter of 3 to 9 μm, and the ratio (X / Y) of the major axis (X) to the minor axis (Y) of the toner is 1.2 to 3.0
Wherein the toner is 1 to 50% by number.

[8] The image forming method according to any one of [5] to [7], wherein the toner has an arithmetic mean value of a shape factor represented by the following formula of 1.3 or more. Image forming method.

Shape factor = ((maximum diameter / 2) ² × π) / projected area

[9] The image forming method according to any one of [5] to [7], wherein the toner is a toner obtained by associating at least resin particles in an aqueous medium.

[10] The image forming method according to any one of [5] to [7], wherein the toner is a toner obtained by polymerizing at least a polymerizable monomer in an aqueous medium. Image forming method.

[11] In a method for producing a toner for developing an electrostatic image, wherein at least resin particles are associated in an aqueous medium, the volume average particle diameter of the toner is 3 to 9 μm,
An electrostatic charge image developing method, wherein the toner having a ratio (X / Y) of the major axis (X) to the minor axis (Y) of 1.2 to 3.0 of the toner is 1 to 50% by number. Of manufacturing toner for toner.

[12] In a method for producing a toner for developing an electrostatic image obtained by polymerizing at least a polymerizable monomer in an aqueous medium, the volume average particle diameter of the toner is 3 to 9 μm.
m, and the ratio (X / Y) of the major axis (X) to the minor axis (Y) of the toner is 1.2 to 3.0, and 1 to 50% by number of toners. A method for producing an electrostatic image developing toner.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present inventors have made intensive studies and found that the above problem can be solved by allowing a toner having a specific shape to exist in a small particle size toner. It has been completed.

That is, the present inventors have conducted intensive studies, and as a result, in order to improve the cleaning property of small particle size toner,
We focused on the shape of the toner. As a result, it has been clarified that it is preferable to use an irregular shape in order to reduce the adhesion to the photoreceptor. However, in the case of a simple irregular shape, when the inside of the developing device is subjected to a stress, its shape changes, the adhesion to the photoreceptor fluctuates, and as a result, the cleaning property deteriorates over a long period of use. Turned out to cause problems.

As a result of analyzing the change in toner shape during use over a long period of time, it was found that the irregularly shaped projections on the surface and the corners were deformed due to abrasion caused by the stress of the developing device and the like. It was presumed that the shape became spherical, the adhesion to the photoreceptor increased, and the cleaning property was reduced.

In order to solve this problem, as a result of diligent studies on the toner shape which does not fluctuate due to stress inside the developing device and which can improve the cleaning property, the long axis of the toner was found. (X) and short axis (Y)
It has been found that by using a toner having a ratio (X / Y) of 1.2 to 3.0 with respect to the above, the cleaning property can be maintained for a long time. Although this shape is indefinite, it is close to a so-called elliptical shape. As a shape, it is hardly affected by shape change due to stress, and there is no shape change even when used for a long time. Can be maintained.
The amount of the toner is 1 to 50 in the entire toner.
What is necessary is that the number% exists. Since this toner has an irregular shape, 50% by number of this toner
When the amount exceeds the range, the cleaning property can be stabilized, but the image quality is deteriorated, and the resolution, which is an advantage of the small particle size toner, is reduced. On the other hand, if less than 1% by number of toners having this shape is present, the effect of improving the cleaning property cannot be exhibited.

The preferred range of the content of the toner having this shape is 5 to 45% by number, more preferably 10 to 4%.
0% by number.

The shape factor can be determined by taking a photograph of a toner particle magnified 1000 times with a scanning electron microscope.
The length of the major axis (X) and the minor axis (Y) of the shape of zero toner are measured, and the value of the ratio (X / Y) is calculated. The number% means that (X / Y) is obtained for each of the 500 toner particles, and (X / Y) of 1.2 to 3.0 is obtained.
Is obtained by calculating the number (A) of toner particles having the following formula:

The method for controlling the shape of the present invention is not particularly limited. For example, a toner in which (X / Y) is adjusted to 1.2 to 3.0 by spraying toner particles into a hot air flow or adding the toner particles to a solvent that does not dissolve the toner and giving a swirling flow, is used. There is a method in which Y) is adjusted by adding it to a normal toner having a value outside the range of 1.2 to 3.0 so as to fall within the range of the present invention. Further, the whole shape is controlled at the stage of preparing a so-called polymerization toner, and (X / Y) is set to 1.
There is a method in which the toner adjusted to 2 to 3.0 is similarly added to a normal toner to adjust.

However, in these methods, since the adjustment is performed by mixing a plurality of particles whose shapes are controlled, the production process becomes complicated. For this reason, as a result of intensive studies, the present inventors have found a method for producing a toner using the polymerization method so as to be within the shape range of the present invention.

That is, in a suspension polymerization method toner in which a toner component such as a colorant is dispersed or dissolved in a so-called polymerizable monomer is suspended in an aqueous medium and then polymerized to obtain a toner. They have found that the shape can be controlled by performing a polymerization reaction using a reaction vessel capable of forming a turbulent flow during the reaction. That is,
When the polymerization proceeds and the oil droplets present in the aqueous medium in the suspended state gradually become polymerized, and the oil droplets become soft particles, the coalescence of the particles is performed by colliding the particles. Promoted and elongated particles, ie (X / Y)
Is used to form a toner having a shape of 1.2 to 3.0.
In this method, the shape of only a part of the toner, not the whole toner, can be changed, so that the distribution of the toner shape can be controlled within the scope of the present invention.

On the other hand, in the case of a polymerization toner formed by associating or fusing resin particles, fusion is performed using a reaction vessel capable of forming a turbulent flow in the fusing step, similarly to the suspension polymerization method. It has been found that the shape can be controlled by performing. That is, when fusion is performed in a turbulent field, strong stress is applied to particles that are undergoing aggregation and fusion (association or aggregated particles), and as a result, the particles become elongated rather than spherical. Go. By utilizing this phenomenon, the shape of only a portion of the toner particles can be changed without changing the shape of the entire toner, and as a result, a toner having the shape range of the present invention can be formed. It is.

As a result of intensive studies, the present inventors have found that turbulence can be formed and the shape can be easily controlled by using a specific stirring blade. The reason for this is not clear, but is commonly used in FIG.
In the case where the configuration of the stirring blade as shown in (1) is one-stage, the flow of the medium formed in the stirring tank is only the flow moving along the wall surface from the lower part to the upper part of the stirring tank. Therefore, conventionally, a turbulent flow is generally formed by disposing a baffle plate such as a wall surface of a stirring tank, and the efficiency of stirring is increased. However, in such a device configuration, although a turbulent flow is partially formed, the turbulent flow acts in a direction in which the flow of the fluid stagnates, and as a result, the slip with respect to the particles is reduced. Can't control.

As a result of intensive studies, the present inventors have paid attention to the structure of the stirring blade, and have found that this problem can be solved by improving the flow of the medium.

A stirring tank having a stirring blade which can be preferably used will be described with reference to the drawings. FIG. 2 is an example of a stirring tank provided with the stirring blade of the present invention. A rotating shaft 3 is suspended from the center of a vertical cylindrical stirring tank 2 having a heat exchange jacket 1 attached to the outer periphery of the stirring tank, and the rotating shaft 3 is brought close to the bottom surface of the stirring tank 2. A lower agitating blade 4 disposed,
There is a stirring blade 5 disposed at an upper stage. Upper stage stirring blade 5
Is disposed at an intersection angle α that precedes the stirring blade 4 located in the lower stage in the rotation direction. In the present invention, the intersection angle α is less than 90 degrees (°). The lower limit of the intersection angle is not particularly limited, but may be about 5 ° or more, preferably 10 ° or more. FIG. 3 shows this in a top sectional view. If there are three or more stages, the intersection angle α between the adjacent stirring blades may be less than 90 degrees.

With this configuration, the medium is first stirred by the stirring blades disposed in the upper stage, and a flow to the lower side is formed. Then, by the stirring blade arranged in the lower stage,
It is presumed that the flow formed by the upper stirring blade is further accelerated downward, and a downward flow is separately formed by the stirring blade itself, so that the flow is accelerated as a whole and proceeds. As a result, a basin having a large shear stress formed as a turbulent flow is formed, and it is presumed that a toner having the shape of the present invention can be formed.
This effect is presumed to be acting similarly in both the suspension polymerization stage and the fusion stage.

In FIGS. 2 and 3, the arrow indicates the direction of rotation, and FIG.
Denotes an upper material inlet and 8 denotes a lower material inlet. Also, 9
Is a turbulent flow forming member for effective stirring.

Here, the shape of the stirring blade is not particularly limited, but is a square plate, a notch in a part of the blade, and one or more middle holes, so-called slits, in the center. Things and the like can be used. These examples are described in FIG. In FIG. 4, (a) shows a case where the stirrer blade has no middle hole portion 6, (b) shows a case where a large middle hole portion is provided at the center, (c) shows a case where there is a horizontally long middle hole portion, and (d) shows a vertically long one. There is a middle hole. Moreover, these may use the thing with a different hole part in an upper stage and a lower stage, or may use the same thing.

FIGS. 5 to 9 show examples of preferable structures which can be used as the structure of the stirring blade. FIG.
Is a configuration having a projection at the end of the stirring blade and / or a bent portion at the end, FIG. 6 is a configuration having a slit in the lower stirring blade and having a bent portion and a projection at the end, and FIG. 7 is an end of the lower stirring blade. FIG. 8 shows a configuration in which an upper stirring blade has a gap and an end of a lower stirring blade has a bent portion and a projection, and FIG. 9 shows a configuration in which the stirring blade has three stages. Each is shown. The angle of the bent portion at the end of the stirring blade is preferably about 5 to 45 °.

The stirring blade having the bent portion and the projection having the upper or lower portion effectively generates turbulence, and is effective for obtaining the shape of the present invention.

The gap between the upper and lower stirring blades having the above configuration is not particularly limited, but it is preferable that at least a gap is provided between the stirring blades. Although the reason is not clear, it is considered that the flow of the medium is formed through the gap, so that the stirring efficiency is improved. However, the gap has a width of 0.5 to 50%, preferably 1 to 30% with respect to the liquid level in the stationary state.

Further, the size of the stirring blade is not particularly limited, but the sum of the heights of all the stirring blades is 50% to 100%, preferably 60% to 100% of the liquid level in the stationary state. 95
%.

The toner of the present invention contains at least a resin and a colorant. If necessary, the toner of the present invention may contain a releasing agent or a charge control agent as a fixing property improving agent. Further, an external additive composed of inorganic fine particles, organic fine particles, and the like may be added to the toner particles containing the resin and the colorant as main components.

The toner of the present invention is obtained by emulsion polymerization of a monomer in a suspension polymerization method or a liquid to which an emulsion of necessary additives is added.
It can be produced by a method of producing fine polymer particles, and then adding an organic solvent, a coagulant and the like to associate.
A method of preparing by mixing and associating with a dispersion liquid such as a release agent or a colorant necessary for the composition of the toner at the time of association, or dispersing a toner component such as a release agent or a colorant in a monomer. And then emulsion polymerization. Here, the association means that a plurality of resin particles and colorant particles are fused.

The term "aqueous medium" as used in the present invention means a medium containing at least 50% by weight of water.

The production method of the suspension polymerization method is not particularly limited, but the following production methods can be used.

That is, a coloring agent and, if necessary, various components such as a release agent, a charge control agent, and a polymerization initiator are added to the polymerizable monomer, and a homogenizer, a sand mill, a sand grinder, an ultrasonic dispersion Various constituent materials are dissolved or dispersed in the polymerizable monomer by a machine or the like. The polymerizable monomer in which these various constituent materials are dissolved or dispersed is dispersed in an aqueous medium containing a dispersion stabilizer into oil droplets of a desired size as a toner using a homomixer, a homogenizer, or the like. Thereafter, the stirring mechanism is moved to the above-described reaction device, which is the stirring blade, and heated to cause the polymerization reaction to proceed. After the completion of the reaction, the toner of the present invention is prepared by removing the dispersion stabilizer, filtering, washing and drying.

Further, as a method for producing the toner of the present invention, a method of adjusting the resin particles by fusing them in an aqueous medium can also be mentioned. Although this method is not particularly limited, for example, JP-A-5-265252, JP-A-6-329947, and JP-A-9-159.
The method disclosed in Japanese Patent Publication No. 04-2004 can be cited. That is, a method of associating a plurality of resin particles and dispersed particles of a constituent material such as a colorant, or fine particles composed of a resin and a colorant, particularly, after dispersing these in water using an emulsifier, the critical aggregation concentration At the same time as adding the above coagulant and salting out, the formed polymer itself is heated and fused at a temperature equal to or higher than the glass transition temperature, and the particles are heated and dried in a fluid state while keeping a water-containing state. Can be formed. Here, an organic solvent infinitely soluble in water may be added together with the coagulant.

As the polymerizable monomer constituting the resin, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-chlorostyrene, 3,4- Dichlorostyrene,
p-phenylstyrene, p-ethylstyrene, 2,4-
Dimethylstyrene, pt-butylstyrene, pn-
Hexylstyrene, pn-octylstyrene, pn
-Nonylstyrene, pn-decylstyrene, pn-
Styrene or a styrene derivative such as dodecylstyrene, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate,
Stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, methacrylate derivatives such as dimethylaminoethyl methacrylate, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate,
T-butyl acrylate, isobutyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, acrylate derivatives such as phenyl acrylate, olefins such as ethylene, propylene and isobutylene; Halogen vinyls such as vinyl chloride, vinylidene chloride, vinyl bromide, vinyl fluoride, and vinylidene fluoride; vinyl esters such as vinyl propionate, vinyl acetate and vinyl benzoate; and vinyl ethers such as vinyl methyl ether and vinyl ethyl ether , Vinyl methyl ketone, vinyl ethyl ketone, vinyl ketones such as vinyl hexyl ketone,
N-vinyl carbazole, N-vinyl indole, N-
There are N-vinyl compounds such as vinylpyrrolidone, vinyl compounds such as vinylnaphthalene and vinylpyridine, and acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile and acrylamide. These vinyl monomers can be used alone or in combination.

Further, it is more preferable to use a polymerizable monomer constituting the resin in combination with one having an ionic dissociation group. For example, those having a substituent such as a carboxyl group, a sulfonic acid group, and a phosphate group as a constituent group of the monomer, specifically, acrylic acid, methacrylic acid,
Maleic acid, itaconic acid, cinnamic acid, fumaric acid, monoalkyl maleate, monoalkyl itaconate, styrenesulfonic acid, allylsulfosuccinic acid, 2-acrylamido-2-methylpropanesulfonic acid, acid phosphooxyethyl Methacrylate,
3-chloro-2-acid phosphooxypropyl methacrylate and the like.

Further, divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate,
Polyfunctional vinyls such as neopentyl glycol diacrylate can be used to form a crosslinked resin.

These polymerizable monomers can be polymerized using a radical polymerization initiator. In this case, an oil-soluble polymerization initiator can be used in the suspension polymerization method. As the oil-soluble polymerization initiator, 2,2'-azobis- (2,4
-Dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1,1'-azobis (cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvalero Nitroles, azo or diazo polymerization initiators such as azobisisobutyronitrile,
Benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide, dicumyl peroxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, 2,2-bis (4,4
Examples thereof include peroxide-based polymerization initiators such as -t-butylperoxycyclohexyl) propane and tris- (t-butylperoxy) triazine, and polymer initiators having a peroxide in a side chain.

When the emulsion polymerization method is used, a water-soluble radical polymerization initiator can be used. Examples of the water-soluble polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate, azobisaminodipropane acetate, azobiscyanovaleric acid and salts thereof, and hydrogen peroxide.

Examples of the dispersion stabilizer include tricalcium phosphate, magnesium phosphate, zinc phosphate, aluminum phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, and calcium sulfate. , Barium sulfate,
Bentonite, silica, alumina and the like can be mentioned. Further, a surfactant generally used as a surfactant such as polyvinyl alcohol, gelatin, methyl cellulose, sodium dodecylbenzenesulfonate, ethylene oxide adduct, and higher alcohol sodium sulfate can be used as a dispersion stabilizer.

The resin excellent in the present invention preferably has a glass transition point of 20 to 90 ° C. and a softening point of 8 ° C.
The thing of 0-220 ° C is preferred. The glass transition point is measured by a differential calorimetric analysis method, and the softening point can be measured by a Koka flow tester. Furthermore, these resins have a number average molecular weight (Mn) of 10 as measured by gel permeation chromatography.
00 to 100000, weight average molecular weight (Mw) 200
Those having 0 to 1,000,000 are preferred. Further, as a molecular weight distribution, Mw / Mn is 1.5 to 100, particularly 1.8.
-70 are preferred.

The flocculant used is not particularly limited, but those selected from metal salts are preferably used. Specifically, as a monovalent metal, for example, a salt of an alkali metal such as sodium, potassium, and lithium, and as a divalent metal, for example, a salt of an alkaline earth metal such as calcium and magnesium, or a divalent metal such as manganese or copper Salt,
Examples include salts of trivalent metals such as iron and aluminum, and specific salts include sodium chloride, potassium chloride, lithium chloride, calcium chloride, zinc chloride, copper sulfate, magnesium sulfate, and manganese sulfate. Can be.
These may be used in combination.

It is preferable that these coagulants are added at a critical coagulation concentration or higher. The critical aggregation concentration is an index relating to the stability of the aqueous dispersion, and indicates the concentration at which aggregation occurs when a coagulant is added. This critical aggregation concentration is
It varies greatly depending on the emulsified component and the dispersant itself. For example, Seizo Okamura et al., “Polymer Chemistry 1
7, 601 (1960), edited by The Society of Polymer Science, Japan, and the like, and a detailed critical aggregation concentration can be determined.
As another method, a desired salt is added to a target particle dispersion at a different concentration, the 添加 (zeta) potential of the dispersion is measured, and the salt concentration at which this value changes is determined as a critical aggregation concentration. You can also.

The addition amount of the coagulant of the present invention may be not less than the critical coagulation concentration, but is preferably 1.2 to the critical coagulation concentration.
It is better to add it at least twice, more preferably at least 1.5 times.

The solvent which is infinitely soluble means a solvent which is infinitely soluble in water. The solvent which does not dissolve the resin formed in the present invention is selected.
Specifically, methanol, ethanol, propanol,
Examples thereof include alcohols such as isopropanol, t-butanol, methoxyethanol and butoxyethanol, nitriles such as acetonitrile, and ethers such as dioxane. Particularly, ethanol, propanol and isopropanol are preferred.

The amount of the solvent to be infinitely dissolved is 1 to 100% by volume based on the polymer-containing dispersion to which the flocculant is added.
Is preferred.

In order to make the shape uniform, it is preferable to prepare a colored particle, filter it, and then carry out fluid drying of a slurry in which 10% by weight or more of water exists relative to the particle. Those having a polar group in the polymer are preferred. It is considered that the reason for this is that the water existing in the polymer having the polar group has an effect of swelling to some extent, so that the shape is particularly easily uniformized.

As the colorant used in the toner of the present invention, carbon black, magnetic substance, dye, pigment and the like can be used arbitrarily. As carbon black, channel black, furnace black, acetylene black, thermal black lamp Black or the like is used. As the magnetic material, ferromagnetic metals such as iron, nickel and cobalt, alloys containing these metals, compounds of ferromagnetic metals such as ferrite and magnetite, alloys which do not contain ferromagnetic metals but show ferromagnetism by heat treatment, For example, an alloy of a type called a Heusler alloy such as manganese-copper-aluminum, manganese-copper-tin, chromium dioxide, or the like can be used.

As the dye, C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 1
22, C.I. I. Solvent Yellow 19, 44, 7
7, 79, 81, 82, 93, 98, 10
3, 104, 112, 162, C.I. I. Solvent Blue 25, 36, 60, 70, 93, 9
5 and the like, and mixtures thereof can also be used. Examples of the pigment include C.I. I. Pigment Red 5,
48: 1, 53: 1, 57: 1, 122, 1
39, 144, 149, 166, 177, 1
78, 222, C.I. I. Pigment Orange 31, 43 and C.I. I. Pigment Yellow 14, 17, and 9
3, 94, 138, C.I. I. Pigment Green 7, C.I. I. Pigment Blue 15: 3, 60 and the like, and mixtures thereof can also be used. The number average primary particle size varies depending on the type, but
About 200 nm is preferable.

As a method of adding a colorant, a method of adding polymer particles prepared by an emulsion polymerization method at the stage of coagulation by adding a coagulant to color the polymer, or a process of polymerizing monomers. And a method of adding a colorant, polymerizing, and forming colored particles can be used. When the colorant is added at the stage of preparing the polymer, it is preferable to use the colorant after treating the surface with a coupling agent or the like so as not to inhibit the radical polymerizability.

Further, low molecular weight polypropylene (number average molecular weight = 1500 to 9000), low molecular weight polyethylene or the like may be added as a fixing property improving agent.

An azo metal complex as a charge control agent,
A quaternary ammonium salt or the like may be used.

Further, in the toner of the present invention, more effects can be exhibited by adding and using fine particles such as inorganic fine particles and organic fine particles as an external additive. The reason for this is presumed to be that, as described above, the burying and detachment of the external additive can be effectively suppressed, and the effect is remarkable.

As the inorganic fine particles, it is preferable to use inorganic oxide particles such as silica, titania, and alumina. Further, these inorganic fine particles may be subjected to a hydrophobic treatment with a silane coupling agent, a titanium coupling agent, or the like. preferable. The degree of the hydrophobizing treatment is not particularly limited, but a methanol wettability of 40 to 95 is preferable. Methanol wettability is to evaluate the wettability to methanol. In this method, an inorganic fine particle to be measured is added to 50 ml of distilled water placed in a beaker having a capacity of 200 ml.
Weigh 2 g and add. Methanol is slowly dropped from a burette whose tip is immersed in the liquid until the whole of the inorganic fine particles is wet with slow stirring. When the amount of methanol required to completely wet the inorganic fine particles is a (ml), the degree of hydrophobicity is calculated by the following equation.

Degree of hydrophobicity = a / (a + 50) × 100 The external additive may be added in an amount of 0.1-5.
0% by weight, preferably 0.5 to 4.0% by weight. Various external additives may be used in combination.

The toner of the present invention has a volume average particle diameter of 3 to 9 μm. This particle size can be controlled by the concentration of the flocculant, the amount of the organic solvent added, and the composition of the polymer itself. Also, toner particles (colored particles)
Is a volume average particle size measured with a Coulter Counter TA-II or a Coulter Multisizer.

It is to be noted that a preferable shape of the toner of the present invention is such that the arithmetic average of the shape factor represented by the following formula is 1.3 or more. More preferably, the number of toner particles having an arithmetic average of the shape coefficient in the range of 1.3 to 2.2 and the shape coefficient in the range of 1.5 to 2.0 is 80% by number or more. .

Shape factor = ((maximum diameter / 2) ² × π) / projected area This shape factor is obtained by taking a photograph in which the toner particles are magnified 500 times with a scanning electron microscope, and SCANNING IMAGE ANALYSE
R "(manufactured by JEOL Ltd.) to analyze the photographic image. At this time, the shape factor of the present invention was measured by the above formula using 500 toner particles.

Although the reason for this is not particularly clear, having this shape makes it possible to make the shape relatively indefinite, so that the surface charge density can be lowered and the adhesion to the photoreceptor or the like can be reduced. This is because cleaning can be facilitated because the temperature can be reduced. Further, since the adhesive force can be reduced, the problem of filming on the photoconductor is reduced.

The toner of the present invention may be used as a one-component magnetic toner containing a magnetic material, for example, when used as a two-component developer by mixing with a so-called carrier, or when the non-magnetic toner is used alone. Any of them can be suitably used, but in the present invention, it is more preferable to use as a two-component developer to be used by mixing with a carrier.

As the carrier constituting the two-component developer, either an uncoated carrier composed of only magnetic material particles such as iron or ferrite, or a resin-coated carrier in which the surface of the magnetic material particles is coated with a resin or the like can be used. Is also good. The average particle size of this carrier is 30 to 1 in terms of volume average particle size.
50 μm is preferred. The resin for coating is not particularly limited, and examples thereof include a styrene-acrylic resin and a silicone resin.

The developing method in which the toner of the present invention can be used is not particularly limited. It can be suitably used for a contact developing method or a non-contact developing method. Further, the toner of the present invention has a high charge rising property, and is useful for a non-contact developing method. That is, in the non-contact development method, since the change in the development electric field is large, a minute change in the charge is large and acts on the development itself. However, since the toner of the present invention has a high charge rising property, the change in charge is small, and a stable charge amount can be secured. Therefore, a stable image can be formed for a long time even by the non-contact developing method. it can.

For the contact type development, the layer thickness of the developer having the toner of the present invention is 0.1 to 8 m in the development area.
m, particularly preferably 0.4 to 5 mm. The gap between the photoconductor and the developer carrier is 0.15 to 7 m.
m, particularly preferably 0.2 to 4 mm.

In the non-contact developing system, the developer layer formed on the developer carrying member does not come into contact with the photoreceptor. It is preferable to be formed by. In this method, a developer layer having a thickness of 20 to 500 μm is formed in a development region on the surface of the developer carrier, and a gap between the photoconductor and the developer carrier has a larger gap than the developer layer. The thin layer is formed by a magnetic blade using a magnetic force or a method of pressing a developer layer regulating rod against the surface of the developer carrier. further,
There is also a method in which a urethane blade, a phosphor bronze plate or the like is brought into contact with the surface of the developer carrier to regulate the developer layer. The pressing force of the pressing regulating member is preferably from 1 to 15 gf / mm. When the pressing force is small, the conveyance is likely to be unstable because the regulating force is insufficient. On the other hand, when the pressing force is large, the stress on the developer is increased, and the durability of the developer is likely to be reduced. A preferred range is 3 to 10 gf / mm. The gap between the developer carrier and the surface of the photoconductor needs to be larger than the developer layer. Further, when a developing bias is applied at the time of development, either a method of applying only a DC component or a method of applying an AC bias may be used.

The size of the developer carrying member is 10 mm in diameter.
Those having a size of ４０40 mm are preferred. When the diameter is small, the mixing of the developer is insufficient, and it is difficult to ensure sufficient mixing to give sufficient charge to the toner. When the diameter is large, the centrifugal force on the developer becomes large. ,
The problem of toner scattering is likely to occur.

Hereinafter, an example of the non-contact developing system will be described with reference to FIGS.
2 will be described.

The developer carrier is constituted by a sleeve in which a magnet fixed inside is arranged, and the developer (toner) is transported to the developing area by rotating the sleeve. The material is preferably stainless steel or aluminum. A particularly preferred example is one in which a phenol resin in which conductive carbon is dispersed is coated on the surface of an aluminum sleeve. The sleeve preferably has a diameter of 10 to 50 mm.

The developer layer regulating member is for uniformly regulating the toner layer on the developer carrier, and may be formed of a magnetic or non-magnetic plate. A method to regulate the toner layer by forming a certain gap between
Alternatively, a method in which a member having rubber elasticity such as urethane is brought into contact with the developer carrying member, and a method in which an elastic metal plate such as a phosphor bronze plate is brought into contact with the developer carrying member can be given.

The developer layer is preferably conveyed to the developer carrier in a layer thinner than the gap (a) between the developer carrier and the electrostatic latent image carrier. The preferred range of the gap (a) is 100 to
The developer layer is transported thinner than this gap, and is preferably transported in a layer of about 50 to 300 μm.

Further, it is preferable to apply an alternating electric field between the developer carrier and the electrostatic latent image carrier. By applying this alternating electric field, the toner can fly effectively. As the condition of the alternating electric field, it is preferable that the AC frequency f is 200 to 4,000 Hz and the AC voltage Vpp is 500 to 3,000 V. When this alternating electric field is used, it is necessary that the toner has uniform chargeability and magnetism. That is, when the toner has a distribution of magnetism and chargeability among toners, the effect of pulling back weakly chargeable toner and the like due to the alternating electric field is offset, and as a result, the effect of improving image quality is reduced. The image quality can be further improved by the shape uniformity and magnetic uniformity of the toner formed by fusing in an aqueous medium as in the present invention.

Hereinafter, the developing device of the image forming method of the present invention will be specifically described.

FIG. 10 is a sectional view showing the structure of the developing device according to the present invention.

In FIG. 10, an image carrier for carrying an electrostatic latent image formed by a known process, for example, an electrophotographic photosensitive drum 11 is rotated in the direction of arrow B. The developing sleeve 18 as a developer carrying member carries the magnetic toner 14 as a magnetic one-component developer supplied by the hopper 13 and rotates in the direction of arrow A, so that the developing sleeve 18 and the photosensitive drum 11 Conveys the toner 14 to the development area D facing. In the developing sleeve 18, a magnet 15 is disposed for magnetically attracting and holding the magnetic toner 14 on the developing sleeve 18. The magnetic toner 14 obtains a triboelectric charge capable of developing the electrostatic latent image on the photosensitive drum 11 by friction with the developing sleeve 18.

In order to regulate the thickness of the magnetic toner 14 conveyed to the developing area D, a regulating blade 12 made of a ferromagnetic metal is moved from the surface of the developing sleeve 18 by 100 to 500 mm.
It is hung from the hopper 13 so as to face the developing sleeve 18 with a gap width of μm. By the magnetic field lines from the magnetic pole N of the magnet 15 being concentrated on the blade 12,
A thin layer of the magnetic toner 14 is formed on the developing sleeve 18. A non-magnetic blade can also be used as the blade 12.

The thickness of the thin layer of the magnetic toner 14 formed on the developing sleeve 18 is preferably smaller than the minimum gap between the developing sleeve 18 and the photosensitive drum 11 in the developing area D. The present invention is particularly effective for a developing device of a type that develops an electrostatic latent image with such a thin toner layer, that is, a non-contact developing type developing device. But,
The present invention can also be applied to a developing device in which the thickness of the toner layer in the developing area is equal to or greater than the minimum gap between the developing sleeve 18 and the photosensitive drum 11, that is, a contact developing type developing device.

For the sake of simplicity, the following description will be made by taking a non-contact developing type developing device as an example.

The developing sleeve 18 is supplied with a developing bias by a power source 19 in order to fly the magnetic toner 14 from the toner layer of the magnetic toner 14 which is a magnetic one-component developer carried on the developing sleeve 18 toward the photosensitive drum 11. A voltage is applied. When a DC voltage is used as the developing bias voltage, a voltage having a value between the potential of the electrostatic latent image portion (the region where the magnetic toner 14 is adhered and visualized) and the potential of the background portion is used. 18 is preferably applied.
On the other hand, in order to increase the density of the developed image or improve the gradation, an alternating bias voltage may be applied to the developing sleeve 18 to form an oscillating electric field in which the direction is alternately reversed in the developing region D. In this case, it is preferable to apply to the developing sleeve 18 an alternating bias voltage on which a DC voltage component having a value between the potential of the image portion and the potential of the background portion is superimposed.

In so-called regular development in which toner is adhered to a high potential portion of an electrostatic latent image having a high potential portion and a low potential portion to visualize the toner, a toner charged to a polarity opposite to the polarity of the electrostatic latent image is used. On the other hand, in so-called reversal development in which toner is adhered to a low-potential portion of an electrostatic latent image to visualize the toner, a toner charged to the same polarity as the polarity of the electrostatic latent image is used. Note that the high potential and the low potential are expressed by absolute values. In any case, the magnetic toner 14 is charged to a polarity for developing the electrostatic latent image by friction with the developing sleeve 18.

FIG. 11 is a sectional view showing the structure of another embodiment of the developing device according to the present invention, and FIG. 12 is a sectional view showing the structure of still another embodiment of the developing device according to the present invention.

In the developing device shown in FIGS. 11 and 12, as a member for regulating the layer thickness of the magnetic toner 14 on the developing sleeve 18, a material having rubber elasticity such as urethane rubber or silicone rubber, phosphor bronze, stainless steel or the like is used. An elastic plate 20 made of a material having metal elasticity is used.
11 is characterized in that the developing device in FIG. 11 is pressed against the developing sleeve 18 in a direction opposite to the rotational direction, and the developing device in FIG. 12 is pressed against the developing sleeve 18 in the same direction as the rotational direction. . In such a developing device, a thinner toner layer can be formed on the developing sleeve 18. Other configurations of the developing device of FIGS. 11 and 12 are shown in FIG.
11 and FIG. 1 are basically the same as the developing device shown in FIG.
2, the same reference numerals as those shown in FIG. 10 indicate the same members.

The developing device for forming a toner layer on the developing sleeve 18 as described above as shown in FIGS. 11 and 12 is suitable for a device using a magnetic one-component developer containing a magnetic toner as a main component. I have. In any case, since the toner is rubbed onto the developing sleeve 18 by the elastic plate 20, the amount of triboelectric charge of the toner increases, and the image density is improved. Therefore, it is suitable for coping with a shortage of toner charge in a high quality environment.

The developing sleeve 18 is formed on the surface of the sleeve base 16 on which fine irregularities are provided, that is, on the rough surface.
A resin coating layer 7 containing and dispersing at least conductive fine particles such as graphite is formed. Magnetic toner 1
4 is triboelectrically charged by the resin coating layer 17 to a polarity for developing a latent image. Fine particles such as graphite contained therein are exposed on the surface of the resin coating layer 17. The conductive fine particles such as graphite leak excessive charge of the toner 14 and have excellent solid lubricating properties, thus helping to reduce the adhesion of the fine powder toner to the developing sleeve 18.

The structure of the cleaning mechanism according to the present invention is as shown in FIG. 13 as a typical example. Reference numeral 31 denotes an elastic blade which is in contact with the photosensitive drum 11 while being held by the holder 33 while a certain amount of contact pressure is applied thereto. In FIG. 13, reference numeral 34 denotes a member for applying the contact pressure.

The latent image forming member (photosensitive drum) 11 is a photosensitive member in an electrophotographic system, and is most often formed on a drum-shaped support. In FIG. 13, the arrow is the traveling direction. Reference numeral 36 denotes the toner on the latent image forming body 11 scraped off by the elastic blade,
5 is a guide plate for guiding to No. 5. The guide plate 36
Is thin and soft, the toner adhering to the latent image forming body once passes under it and is scraped off by an elastic blade. Reference numeral 37 denotes an outer wall of the cleaning mechanism.

FIG. 14 shows a situation where the toner on the latent image forming body 11 is scraped off by the elastic blade 31. As described above, the toner tends to accumulate and be crushed at the tip of the elastic blade 31.

FIG. 15 shows a holder 33 of the elastic blade 31.
FIG. 4 is a view for explaining an intersection angle φ between the image forming body and the latent image forming body 11.
That is, when the intersection angle φ is less than 90 °, the extension line is extended in the direction (Y-Y) in which the elastic blade of the holder is supported, and the intersection angle φ reaches the surface of the latent image forming body at the position where the surface reaches the latent image forming surface. When a tangent (XX) is drawn, it means that the angle between the tangent and the extension is less than 90 °.

If this angle is 90 ° or more and sufficient cleaning performance is to be ensured, there is a problem that toner adheres to the latent image forming member during a long-term use due to the force acting to crush the toner. Is not secured.
Although there is no particular lower limit angle,
It is preferable that the angle is 15 ° or more in terms of cleaning power. In addition, a preferable range of the angle is 20 to
90 °, more preferably 25 to 80 °.

Further, as the material of the elastic blade used in the present invention, urethane rubber, silicone rubber, fluorine rubber, chloroprene rubber, butadiene rubber and the like can be used. Among them, urethane rubber-based materials are preferable. Particularly, as described in JP-A-59-30574, a polycaprolactone ester containing a caprolactone ester component of 30% by weight or more and having an average molecular weight of 1,000 to 4,000 is mixed with a polyisocyanate. Urethane rubber obtained by reaction curing is preferred.

The average molecular weight is determined from the amount of potassium hydroxide that neutralizes acetic acid generated when an acetylation reaction is performed on polycaprolactone ester using an acetylating reagent consisting of acetic anhydride and pyridine to determine the amount of terminal OH. The group was quantified and the number average molecular weight was calculated.

The general formula of the polycaprolactone ester preferably used in the present invention can be shown below.

HO-[-X _1- ] _m -R-[-X _2- ] _n -OH wherein X ₁ and X ₂ are cleavage residues of a caprolactone ring and may be the same or different from each other. Well, the sum of m and n is 2
-35, m: n = 3: 1 to 1: 3. R is a linking group of X ₁ and X ₂ and is a divalent organic group having 300 or less carbon atoms. The compound represented by the above general formula has an average molecular weight of 1,000 to 4,000, and the content of the caprolactone ester component is 30% by weight or more.

The average molecular weight is determined by adding the esterification reagent consisting of acetic anhydride and pyridine to the polycaprolactone ester, acetylating the polycaprolactone ester at a specified reaction temperature and for a certain period of time, and neutralizing the acetic acid produced. Shows the value when the terminal OH group is quantified and the number average molecular weight is measured.

In order to produce this polycaprolactone ester, the same or different caprolactone compounds 2
One mole of the polymerization initiator is added to 35 moles,
The polycaprolactone ester having an average molecular weight of 1,000 to 4,000 is obtained by ring-opening addition polymerization at 0 to 300 ° C. Examples of the polymerization initiator include -OH group, -N
Organic compounds having two or more active hydrogens such as an H ₂ group or an —SH group can be given.

The caprolactone compound for forming the caprolactone ring-cleaving residue represented by the above general formula is a compound having a 3- to 7-membered ring and having 6 carbon atoms. Those to which a lower alkyl group such as a methyl group or an ethyl group is bonded are also included.

Specific examples are shown below.

[0110]

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[0111]

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Further, examples of the polymerization initiator for forming the linking group R in the above general formula include the following compound examples.

[0113]

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[0114]

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[0115]

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The commercially available polycaprolactone ester advantageously used for the cleaning blade according to the present invention includes, for example, the following brand names.

"NIAXPCP 0240" (manufactured by Union Carbide) "CATA 220" (manufactured by Rapolde) "ODX 640" (manufactured by Dainippon Ink and Chemicals) It reacts to form urethane rubber, which is the material of the cleaning blade according to the present invention. Here, as the polyisocyanate, for example, the following can be mentioned as preferable ones.

[0118]

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[0119]

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[0120]

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[0121]

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[0122]

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Further, specific examples of the curing agent include the following.

[0124]

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[0125]

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The method for producing the cleaning blade composed of the above polycaprolactone ester and the like is not particularly limited. For example, the following method can be used.

That is, the dehydrated polycaprolactone ester and polyisocyanate are mixed and reacted at a temperature of 70 to 150 ° C. for 10 to 120 minutes to prepare a urethane prepolymer. And a liquid rubber composition by adding a curing agent in a ratio such that the ratio of the number of moles of isocyanate groups to the number of moles of hydroxyl groups and / or amino groups by the polyester and the curing agent becomes 1.00 to 1.30. Making,
This rubber composition is poured into a centrifugal casting machine kept at a temperature of 140 ° C., for example. Then, the film is stretched to a uniform thickness on the inner surface of the rotor by the centrifugal force rotated at a high speed to form a cylindrical film. Thereafter, a cross-linking reaction by the curing agent proceeds and is solidified to form a urethane rubber.

In the present invention, the elastic blade preferably has a pressing force of 15 to 25 g / cm when used, and has a physical property of a hardness of 60 to 9 measured according to JIS K 6301.
It is preferable that the material has 0 °, a tensile strength of 250 kg / cm ² or more, and a rebound resilience of 20 kg / cm ² or more. Preferably, it has a tensile strength of 250 to 800 kg / cm ² , more preferably 300 to 600 kg / cm ² , and a rebound resilience of 20 to 800 kg / cm ² .
-100 kg / cm ² , more preferably 30-90 kg
/ Cm ² .

A preferred fixing method used in the present invention is a hot roll fixing method.

In this fixing system, in many cases, a heat source is provided inside a metal cylinder made of iron, aluminum, or the like having a surface coated with tetrafluoroethylene or polytetrafluoroethylene-perfluoroalkoxyvinyl ether copolymer or the like. It is formed of a roller and a lower roller formed of silicone rubber or the like. As a heat source, a linear heater was used, and the surface temperature of the upper roller was set to 1
Heating to about 20 to 200 ° C. is a typical example. In the fixing section, pressure is applied between the upper roller and the lower roller to deform the lower roller and form a so-called nip. The nip width is 1 to 10 mm, preferably 1.5
７7 mm. The fixing linear velocity is 40 mm / sec to 400
mm / sec is preferred. When the nip is narrow, heat cannot be uniformly applied to the toner, causing uneven fixing. On the other hand, if the nip width is wide, the melting of the resin is promoted, and a problem occurs in that the fixing offset becomes excessive.

A fixing cleaning mechanism may be provided for use. As this method, a method in which a silicone oil is supplied to a roller or a film after fixing, or a method in which a silicone oil-impregnated pad, roller, web or the like is used for cleaning can be used.

[0132]

The present invention will be further described with reference to embodiments thereof, but of course, embodiments of the present invention are not limited thereto.

(Production Example of Colored Particle 1: Example of Emulsion Polymerization Method) n
-0.90 kg of sodium dodecyl sulfate and 10.0 of pure water
and dissolve with stirring. To this solution, add Regal 330R
After gradually adding 1.20 kg (carbon black manufactured by Cabot Corporation) and stirring well for 1 hour, the mixture was continuously dispersed for 20 hours using a sand grinder (medium type disperser).
This is referred to as “colorant dispersion liquid 1”. A solution composed of 0.055 kg of sodium dodecylbenzenesulfonate and 4.0 l of ion-exchanged water is referred to as “anionic surfactant solution A”.

0.014 kg of a 10 mol adduct of nonylphenol polyethylene oxide and 4.0 l of ion-exchanged water
Is referred to as “nonionic surfactant solution B”.
223.8 g of potassium persulfate was added to 12.0 l of deionized water.
Is referred to as "initiator solution C".

A 100-liter GL (glass lining) reactor equipped with a temperature sensor, a cooling pipe, and a nitrogen introducing device was charged with W
3.41 kg of AX emulsion (polypropylene emulsion having a number average molecular weight of 3,000: number average primary particle size = 120 nm / solid concentration = 29.9%), the whole amount of “anionic surfactant solution A” and “nonionic surfactant solution B” Add the whole amount and start stirring. Next, ion-exchanged water 4
Add 4.0 l.

Heating was started, and when the liquid temperature reached 75 ° C., the entire amount of “initiator solution C” was added dropwise. Then, while controlling the liquid temperature to 75 ° C. ± 1 ° C., the styrene 1
2.1 kg, n-butyl acrylate 2.88 kg, methacrylic acid 1.04 kg and t-dodecyl mercaptan 54
8 g are added dropwise. After the completion of the dropwise addition, the temperature of the solution was raised to 80 ° C. ± 1 ° C., and the mixture was heated and stirred for 6 hours. Next, the liquid temperature was cooled to 40 ° C. or lower, stirring was stopped, and the mixture was filtered with a pole filter to obtain “latex-A”.

The glass transition temperature of the resin particles in Latex-A is 57 ° C., the softening point is 121 ° C., and the molecular weight distribution is as follows: weight average molecular weight = 12.7 million, weight average particle size is 12
It was 0 nm.

A solution obtained by dissolving 0.055 kg of sodium dodecylbenzenesulfonate in 4.0 l of ion-exchanged pure water is referred to as “anionic surfactant solution D”. Also,
A solution obtained by dissolving 0.014 kg of nonylphenol polyethylene oxide 10 mol adduct in 4.0 l of ion-exchanged water is referred to as “nonionic surfactant solution E”.

Potassium persulfate (Kanto Chemical) 200.
A solution obtained by dissolving 7 g in 12.0 l of ion-exchanged water is referred to as "initiator solution F".

A WAX emulsion (polypropylene emulsion having a number average molecular weight of 3000: number average primary particle diameter: 120 nm / solids concentration: 29.9) was placed in a 100-liter GL reactor equipped with a temperature sensor, a cooling pipe, a nitrogen introducing device, and a comb baffle. %), 3.41 kg, the whole amount of “anionic surfactant solution D” and the whole amount of “nonionic surfactant solution E” are added, and stirring is started. Then, ion-exchanged water 44.0
1 is input. Heating is started, and when the liquid temperature reaches 70 ° C., “Initiator solution F” is added. Then, 11.0 kg of styrene and 4.00 kg of n-butyl acrylate
And 1.04 kg of methacrylic acid and 9.02 g of t-dodecylmercaptan are added dropwise.
After completion of the dropwise addition, the mixture was heated and stirred for 6 hours while controlling the liquid temperature to 72 ° C. ± 2 ° C. Further, the liquid temperature was raised to 80 ° C. ± 2 ° C., and the mixture was heated and stirred for 12 hours. The liquid temperature is cooled to 40 ° C. or less, and the stirring is stopped. Filter with a pole filter,
This filtrate was designated as "latex-B".

The glass transition temperature of the resin particles in the latex-B was 58 ° C., the softening point was 132 ° C., and the molecular weight distribution was weight average molecular weight = 245,000 and weight average particle diameter was 11
It was 0 nm.

Sodium chloride as salting-out agent 5.36k
g in 20.0 l of ion-exchanged water is referred to as "sodium chloride solution G".

A solution obtained by dissolving 1.00 g of a fluorine-based nonionic surfactant in 1.00 l of ion-exchanged water is referred to as "nonionic surfactant solution H".

A temperature sensor, a cooling pipe, a nitrogen introducing device,
In a 00 l SUS reaction vessel, 20.0 kg of the latex-A prepared above, 5.2 kg of latex-B, 0.4 kg of colorant dispersion 1 and 20.0 k of ion-exchanged water were prepared.
g and stir. Then, the mixture was heated to 40 ° C., and sodium chloride solution G and isopropanol (manufactured by Kanto Chemical Co., Ltd.)
6.00 kg of nonionic surfactant solution H are added in this order. Then, after leaving it to stand for 10 minutes, the temperature is started to rise to a liquid temperature of 85 ° C. in 60 minutes. Liquid temperature 85 ° C
Heat and stir at ± 2 ° C. for 6 hours for salting out / fusion. Thereafter, the mixture is cooled to 40 ° C. or less and the stirring is stopped. Aperture 45
The solution is filtered through a sieve of μm, and this filtrate is used as an association liquid. Next, non-spherical particles in the form of a wet cake were collected by filtration from the associated liquid using a Nutsche. Thereafter, the substrate was washed with ion-exchanged water.

The non-spherical particles were dried at a suction air temperature of 60 ° C. using a flash jet drier, and then dried at a temperature of 60 ° C. using a fluidized bed drier. The obtained colored particles had a volume average particle size of 6.5 μm, a weight average molecular weight (Mw) of 67,000, a number average molecular weight (Mn) of 5,800, and Mw / Mn = 11.5. Was.

(Production Example 2 of Colored Particles: Example of Emulsion Polymerization Method) In Production Example 1 of colored particles, a magnetic powder (spherical magnetite: number average primary particle size = 210 nm) was used instead of carbon black as a coloring agent. Colored particles were obtained in the same manner except that 0 kg was used. Its volume average particle size is 6.3 μm
Met. The weight average molecular weight (Mw) is 67,000, the number average molecular weight (Mn) is 5,800, and Mw / Mn = 11.1.
It was 5.

(Production Example 3 of Colored Particles: Example of Suspension Polymerization Method) Styrene = 165 g, n-butyl acrylate = 35 g,
Carbon black = 10 g, metal di-t-butylsalicylate = 2 g, styrene-methacrylic acid copolymer =
8 g and paraffin wax (mp = 70 ° C.) = 20 g were heated to 60 ° C. and uniformly dissolved and dispersed at 12,000 rpm with a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.). 10 g of 2'-azobis (2,4-valeronitrile) was added and dissolved to prepare a polymerizable monomer composition. Then, 450 g of a 0.1 M sodium phosphate aqueous solution was added to 710 g of ion-exchanged water, and the mixture was stirred at 13000 rpm with a TK homomixer for 1.0 g.
68 g of M calcium chloride was gradually added to prepare a suspension in which tricalcium phosphate was dispersed. The polymerizable monomer composition was added to the suspension, and the suspension was added to a TK homomixer.
The mixture was stirred at 000 rpm for 20 minutes to granulate the polymerizable monomer composition. Thereafter, the reaction was carried out at 80 ° C. for 10 hours using a reaction apparatus having a different configuration of the stirring blade. Tricalcium phosphate was dissolved and removed with hydrochloric acid, followed by filtration, washing and drying to obtain colored particles having a volume average particle size of 6.9 μm. The weight average molecular weight (Mw) was 78,000, the number average molecular weight (Mn) was 5,900, and Mw / Mn = 13.2.

(Coloring Particle Production Example 4: Example of Suspension Polymerization Method) In Coloring Particle Production Example 3, 120 g of magnetic powder (spherical magnetite: number average primary particle diameter = 210 nm) was used instead of carbon black as a coloring agent. Except for using, colored particles were obtained in the same manner. This had a volume average particle size of 6.7 μm. The weight average molecular weight (Mw) was 78,000, the number average molecular weight (Mn) was 5,900, and Mw / Mn = 13.2.

Tables 1 and 2 below show examples in which the configuration of the stirring tank was variously changed in the production examples of the colored particles and the shapes of the particles.

The percentage in the gap between the upper and lower stages and the height of the stirring blade is the ratio to the liquid level in the stationary state.

[0151]

[Table 1]

[0152]

[Table 2]

* In the colored particles 33 to 36, the number of rotations of the stirring blade was doubled as compared with the others.

External additives shown separately were added to the colored particles 1 to 48, and mixed with a Henschel mixer to prepare a toner.

[0155]

[Table 3]

[0156]

[Table 4]

* Silica A: number average primary particle diameter = 12 nm
/ Hexamethyldisilazane treatment / hydrophobicity = 69 * Silica B: number average primary particle size = 12 nm / dimethyl silicone oil treatment / hydrophobicity = 68 * Silica C: number average primary particle size = 10 nm / dichlorodimethylsilane treatment / Titania A: number-average primary particle size = 25 nm / octyltrimethoxysilane treatment / hydrophobicity = 64 * Titania B: number-average primary particle size = 35 nm / hexyltrimethoxysilane treatment / hydrophobicity = 68 * titania C: number average primary particle size = 20 nm / zinc stearate treatment / hydrophobization degree = 58 evaluation (contact development system: two-component development) Toners 1 to 16 and toners 33, 35, 37, 39, 4
1, 43, 45, and 47 were mixed with a ferrite carrier coated with a silicone resin and having a volume average particle diameter of 60 μm to prepare a developer having a toner concentration of 6%.

Using the developer prepared as described above, a real copying evaluation was carried out using a digital copying machine Konica 7060 manufactured by Konica Corporation. The conditions are as shown below. A laminated organic photoreceptor was used as the photoreceptor.

Developing conditions DC bias; -500 V Dsd (distance between photoconductor and developing sleeve); 600 μm Developer layer regulation: Magnetic H-Cut system Developer layer thickness: 700 μm Developing sleeve diameter: 40 mm Also remaining on the photoconductor The untransferred toner has a thickness of 3.0 mm
A cleaning method using a urethane rubber blade was adopted. The angle formed between the blade and the photoconductor was 45 °.

The urethane rubber blade is A-5.
Is obtained by polymerizing ε-caprolactone with ethylene glycol and having a caprolactone content of 98% by weight and an average molecular weight of 2500, adding diphenylmethane diisocyanate as an isocyanate, and adding 100% at 70 ° C.
For 1 minute, then add 1,4 butanediol as a cross-linking agent and react at 120 ° C., further put into a centrifugal casting machine, and rotate at 1000 rpm at 140 ° C. for 8 minutes.
The one obtained by reacting for 0 minutes was used. JIS K
The hardness measured at 6301 is 70 ° and the tensile strength is 3
93 kg / cm ² and rebound resilience are 52 kg / cm ² . Further, the pressing force was 18 g / cm. Note that the toners 9 to
When using No. 16 and toners 35, 39, 43, and 47, cleaning may not be completely performed by blade cleaning. Therefore, a fur brush was installed before blade cleaning to improve cleaning performance.

The image support to be used has a continuous weight of 55 k
g of plain paper was used to form an image in the horizontal direction. Also,
Image forming conditions include a low temperature and low humidity environment (10 ° C., 15% R
H) and a high-temperature and high-humidity environment (30 ° C., 80% RH) were used to evaluate printing using the above developer.
Printing was performed continuously using a halftone image in which a one-dot image was formed at two-dot intervals, and a total of 50,000 sheets were printed. With respect to the image after 50,000 sheets (50 kc), the presence or absence of an image defect was visually determined.

The criteria are as follows.

Rank A: No image defect, Rank B: Black spots having a diameter of 0.5 mm or less were added to the solid white image.
Rank C: 0.5% or less black spots on solid white image
Rank D: 5 black spots with a diameter of 0.5 mm or less on the solid white image
There are black spots that are present in excess of 0.5 mm in diameter.

The image quality was evaluated by comparing the maximum density and the fog density of the image. The image density was compared with the absolute reflection density using RD-918 manufactured by Macbeth. Fog was compared by relative reflection density where the density of paper was "0".

The results are shown below.

[0166]

[Table 5]

[0167]

[Table 6]

Evaluation (Non-contact development system: magnetic one-component development) Toners 17 to 32 and toners 34, 3 prepared above
Using 6, 38, 40, 42, 44, 46 and 48, a Konica 7050 digital copying machine manufactured by Konica Co., Ltd. was modified and changed to magnetic one-component development to evaluate a real image. The conditions are as shown below. A laminated organic photoreceptor was used as the photoreceptor.

Charger: Scorotron Charged voltage: Photoconductor charge potential (initial charge potential) 720 V Development condition DC bias: -500 V AC bias: Vpp = 1800 V, frequency = 20 k
Hz Dsd (distance between photoreceptor and developing sleeve); 600 μm Developer layer regulation; magnetic H-Cut method Developer layer thickness: 300 μm Developing sleeve diameter: 40 mm (with phenol resin coating with conductive carbon black dispersed on the surface) The untransferred toner remaining on the photoconductor has a thickness of 3.0 mm.
A cleaning method using a urethane rubber blade was adopted. The angle formed between the blade and the photoconductor was 45 °.

The urethane rubber blade is A-5.
Is obtained by polymerizing ε-caprolactone with ethylene glycol, having a caprolactone content of 99% by weight and an average molecular weight of 3900, adding diphenylmethane diisocyanate as an isocyanate, and adding 100% at 70 ° C.
For 1 minute, then add 1,4 butanediol as a cross-linking agent and react at 120 ° C., further put into a centrifugal casting machine, and rotate at 1000 rpm at 140 ° C. for 8 minutes.
The one obtained by reacting for 0 minutes was used. JIS K
The hardness measured at 6301 is 65 ° and the tensile strength is 3
74 kg / cm ² and rebound resilience are 55 kg / cm ² . Further, the pressing force was 18 g / cm. The toner 25
When using ~ 32, 36, 40, 44, 48,
Since cleaning may not be completely performed by blade cleaning, a fur brush is provided before blade cleaning to improve the cleaning performance.

The image support to be used has a continuous weight of 55 k
g of plain paper was used to form an image in the horizontal direction. Also,
Image forming conditions include a low temperature and low humidity environment (10 ° C., 15% R
H) and a high-temperature and high-humidity environment (30 ° C., 80% RH) were used to evaluate printing using the above developer.
Printing was performed continuously using a halftone image in which a one-dot image was formed at two-dot intervals, and a total of 50,000 sheets were printed. With respect to the image after 50,000 sheets (50 kc), the presence or absence of an image defect was visually determined.

The criteria are as follows.

Rank A: No image defect, Rank B: Black spots with a diameter of 0.5 mm or less were added to the solid white image.
Rank C: 0.5% or less black spots on solid white image
Rank D: 5 black spots with a diameter of 0.5 mm or less on the solid white image
There are black spots that are present in excess of 0.5 mm in diameter.

For evaluation of image quality, the maximum density and fog density of the image were compared. The image density was compared with the absolute reflection density using RD-918 manufactured by Macbeth. Fog was compared by relative reflection density where the density of paper was "0".

The results are shown below.

[0176]

[Table 7]

[0177]

[Table 8]

As is clear from Tables 5 to 8, only those in the present invention show good characteristics even after printing 50,000 sheets.

[0179]

According to the present invention, a toner for developing an electrostatic image having a small particle diameter, a method for producing the same, and a method for producing the same, which can form a stable image over a long period of time even in various environments such as high temperature, high humidity and low temperature and low humidity. An image forming method can be provided.

[Brief description of the drawings]

FIG. 1 is a perspective view of a conventional stirring tank having a single-stage stirring blade.

FIG. 2 is a perspective view of an example of a stirring tank provided with the stirring blade of the present invention.

FIG. 3 is a top cross-sectional view of an example of a stirring tank provided with the stirring blade of the present invention.

FIG. 4 is a front view of an example of a stirring blade used in the stirring tank of the present invention.

FIG. 5 is a perspective view of an example of a stirring tank provided with the stirring blade of the present invention.

FIG. 6 is a perspective view of an example of a stirring tank provided with the stirring blade of the present invention.

FIG. 7 is a perspective view of an example of a stirring tank provided with the stirring blade of the present invention.

FIG. 8 is a perspective view of an example of a stirring tank provided with the stirring blade of the present invention.

FIG. 9 is a perspective view of an example of a stirring tank provided with the stirring blade of the present invention.

FIG. 10 is a sectional view of an example of a non-contact developing type developing device.

FIG. 11 is a sectional view of an example of a non-contact developing type developing device.

FIG. 12 is a cross-sectional view of an example of a non-contact developing type developing device.

FIG. 13 is a sectional view of the configuration of a cleaning mechanism according to the present invention.

FIG. 14 is a cross-sectional view illustrating a configuration of a cleaning mechanism for scraping off toner.

FIG. 15 is a configuration cross-sectional view illustrating an angle of a blade holder of the cleaning mechanism.

FIG. 16 is a perspective view of an example of a stirring tank provided with a stirring blade for a comparative example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Jacket 2 Stirring tank 3 Rotating shaft 4 Lower stirring blade 5 Upper stirring blade 11 Photoconductor drum (latent image forming body) 13 Hopper 14 Magnetic toner 15 Magnet 18 Developing sleeve 31 Elastic blade 33 Holder

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Makoto Kono 2970 Ishikawa-cho, Hachioji-shi, Tokyo Konica Corporation F-term (reference) 2H005 AA15 AB03 AB06 EA05 EA07 2H077 AD06 AD13 AD17 AD23 AD24 AD36 AE04 EA03 EA13 EA16 FA13 FA27

Claims (12)

[Claims] 1. A toner for developing an electrostatic image comprising at least a resin and a colorant, wherein the toner has a volume average particle diameter of 3 to 9 μm, and has a major axis (X) and a minor axis (Y) of the toner.
And the ratio (X / Y) of the toner is 1.2 to 3.0.
50% by number of toner for developing an electrostatic image. 2. An electrostatic image developing toner according to claim 1, wherein the toner has an arithmetic average of 1.3 or more of a shape factor represented by the following equation. Shape factor = ((maximum diameter / 2) ² × π) / projected area 3. The toner according to claim 1, wherein the toner is a toner obtained by associating at least resin particles in an aqueous medium. 4. The toner according to claim 1, wherein the toner is a toner obtained by polymerizing at least a polymerizable monomer in an aqueous medium. 5. An image forming method in which an electrostatic latent image formed on a photoreceptor is brought into contact with a developer layer formed on a developer conveying member to visualize the image, wherein the developer has a volume average particle size. An electrostatic image developing toner having a diameter of 3 to 9 μm, wherein the ratio (X / Y) of the major axis (X) to the minor axis (Y) of the toner is 1.2 to 3.0.
Wherein the toner is 1 to 50% by number. 6. An electrostatic latent image formed on a photoreceptor is opposed to a developer layer formed on a developer transport member in a non-contact state, and only a toner for developing an electrostatic image is caused to fly, thereby a visible image. The developer has a volume average particle diameter of 3
And a ratio (X / Y) of the major axis (X) to the minor axis (Y) of 1.2 to 3.0 μm.
Wherein the toner is 1 to 50% by number. 7. An image forming method for developing an electrostatic latent image formed on a photoconductor with a developer containing toner, transferring the electrostatic latent image to an image support, and cleaning the toner remaining on the photoconductor. The developer has a volume average particle size of 3 to 9;
μm toner for developing electrostatic images, the major axis (X) of the toner
The ratio (X / Y) of the toner to the minor axis (Y) of 1.2 to 3.0 is 1 to 50% by number. 8. The image forming method according to claim 5, wherein the toner has an arithmetic average value of a shape coefficient represented by the following equation of 1.3 or more. Forming method. Shape factor = ((maximum diameter / 2) ² × π) / projected area 9. The image forming method according to claim 5, wherein the toner is a toner obtained by associating at least resin particles in an aqueous medium. 10. The image forming method according to claim 5, wherein the toner is a toner obtained by polymerizing at least a polymerizable monomer in an aqueous medium. Image forming method. 11. A method for producing a toner for developing an electrostatic charge image comprising at least resin particles associated in an aqueous medium, wherein the volume average particle diameter of the toner is 3 to 9 μm, and the major axis (X) of the toner is And the ratio (X / Y) of the short axis (Y) to 1.
A method for producing a toner for developing an electrostatic image, wherein the toner having a ratio of 2 to 3.0 is 1 to 50% by number. 12. A method for producing a toner for developing an electrostatic image obtained by polymerizing at least a polymerizable monomer in an aqueous medium, wherein the volume average particle diameter of the toner is 3 to 9 μm. Of the major axis (X) and the minor axis (Y) (X /
A method for producing a toner for developing an electrostatic charge image, wherein the toner having Y) of 1.2 to 3.0 is 1 to 50% by number.