JPH09230622A - Electrostatic charge image developing toner, its manufacture and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner for electrostatic charge development which shows a stable charging performance for a long time, has a high and stable transcribing characteristic, and excels in the fluidity, to offer a method for manufacturing such toner, and establish a method for forming images using it. SOLUTION: Particulates are added to colored particles consisting of a resin, colorant, or the like so that a toner for electrostatic charge development is formed, wherein the mean particle size by volume ranges between 50 and 1000nm. Organic particulates whose frictional charging characteristic relative to a frictional charging member has the same polarities as the above-mentioned colored particles are fixed to the surfaces of the colored particles, and then inorganic particulates having the mean particle size by volume between 5 and 50nm are added to generate admixture.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic charge image developing toner used in electrophotographic copying machines and printers, a method for producing the toner, and an image forming method using the toner.

[0002]

2. Description of the Related Art Conventionally, in copying machines and printers using an electrophotographic method, a method of visualizing an electrostatic latent image using resin particles containing a colorant has been generally used. External additives are used for the purpose of charge control, improvement of fluidity and the like.

In a color copying machine or a color printer, a method of forming an image by superimposing a plurality of basic colors is generally used. For the purpose of downsizing and preventing color misregistration, a developer is used as a photoreceptor. On the other hand, a non-contact development batch transfer method has been proposed in which development is carried out in a non-contact state, all the colors are superposed on a photoconductor, and then they are collectively transferred to a transfer paper.

In such a process, at the time of development, the physical adhesive force between the toner and the carrier or between the toner and the developer carrying member contributes to the development. However, if the external additive of the toner is buried in the toner, the physical adhesive force of the toner increases, the developability deteriorates, the transfer unevenness at the time of batch transfer, the fluidity decreases, and the charge control effect decreases due to the decrease in the charge control effect.

In order to solve such a problem, Japanese Patent Laid-Open No. 58-58
No. 1157, a method using an external additive having a large particle size, and JP-A-48-8141 disclose a method using organic fine particles as an external additive having a large particle size. However, when such an external additive having a large particle diameter is added, the effect of improving the fluidity is smaller as the external additive having a smaller particle diameter, the external additive is easily separated from the toner, and the released external additive is This may cause scratches on the drum, blades, etc., and in some cases form aggregates, causing a sliding phenomenon on the rotating sleeve, and the image area developed in such a state has low image density and This also causes image defects such as the occurrence of a part that is white and not developed.

Japanese Unexamined Patent Publication (Kokai) No. 2-167561 discloses a method for fixing an external additive having a large particle diameter. Thereby, the detachment of the external additive can be prevented, and the occurrence of image defects as described above can be suppressed. However, the fluidity cannot be improved so much because the external additive cannot move freely due to the immobilization and the unevenness of the toner surface apparently increases.

Japanese Patent Laid-Open No. 4-335357 discloses a method of fixing a large particle size external additive and then adding and mixing an external additive having a relatively small particle size to improve fluidity. However, when the external additive having a large particle size is an organic fine particle, since the charge retention ability is high, the distribution of the charge on the colored particle surface is likely to be ubiquitous, causing cissing at the time of transfer and in some cases electrostatic agglomeration. As a result, the flow characteristics change and other problems occur. Due to this, the mixing property of the toner is deteriorated, the charging rise is deteriorated, and the charge amount distribution becomes broad, which may cause a problem such as fogging.

[0008]

When the organic fine particles are immobilized, it is important that the colored particles and the organic fine particles to be immobilized have the same charge polarity. As described above, since the organic fine particles have a relatively large charge retention ability, the charge distribution on the surface of the colored particles tends to be ubiquitous. This uneven distribution causes deterioration of fluidity, and causes problems such as transfer repellency and poor fluidity in the hopper due to poor fluidity and accompanying replenishment, decrease in charging rise, and fog.

An object of the present invention is to provide a toner for electrostatic charge development which has stable chargeability for a long period of time without desorption of large-sized organic fine particles, has high and stable transfer characteristics, and has excellent fluidity. To provide.

[0010]

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

(1) In a toner for developing an electrostatic charge image, which comprises fine particles added to and mixed with colored particles comprising at least a resin and a colorant, the toner has a volume average particle size of 50 to 1
At 000 nm, the organic fine particles whose triboelectrification property with the triboelectrification member has the same polarity as the colored particles are immobilized on the surface of the colored particles,
A toner for developing an electrostatic charge image, further comprising inorganic fine particles having a volume average particle diameter of 5 to 50 nm added and mixed.

(2) In a process for producing a toner for developing an electrostatic charge image, which comprises mixing and mixing fine particles to colored particles comprising at least a resin and a colorant, the toner has a volume average particle diameter of 50 to 1000 nm and friction. An electrostatic charge image characterized in that organic fine particles having the same triboelectricity as the colored particles and having triboelectricity with a charging member are fixed on the surface of the colored particles, and then inorganic fine particles having a volume average particle diameter of 5 to 50 nm are further added and mixed. Method for producing developing toner.

(3) The fixing step and the external additive mixing step are performed in the same apparatus, and the temperature of the colored particles during the fixing step is Tg-20 when the glass transition temperature of the resin is Tg.
(° C.) ≦ immobilization treatment temperature ≦ Tg + 20 (° C.) in the temperature range of at least 1 (min) ≦ holding time ≦ 60 (mi
The method for producing a toner according to (2), characterized in that the external additive mixing step is performed within a temperature range of Tg-20 (° C.) ≧ external addition mixing temperature after holding for n).

(4) In the fixing step and the external additive mixing step, the tip peripheral speed of the stirring blade of the mixer is processed in the speed range as shown below. A method for producing a toner for developing a charge image.

10 (m / sec) ≦ fixing step ≦ external additive mixing step ≦ 40 (m / sec) (5) The stirring peripheral speed during the external additive mixing step is V (m / se).
c) The method for producing a toner for developing an electrostatic charge image according to (3), characterized in that the treatment is carried out within the following range when the mixing time is T (sec).

2000 (m) ≤ VT T 8000 (m) (6) A developer composed of a toner for developing an electrostatic charge image and a carrier prepared by adding and mixing fine particles to colored particles composed of at least a resin and a colorant. In an image forming method of developing an electrostatic latent image formed on an electrostatic latent image forming member using a developing device containing a magnet, the toner has a volume average particle diameter of 50
~ 1000 nm, the organic particles having the same triboelectricity with the triboelectrification member and the same polarity as the colored particles are fixed on the surface of the colored particles, and then the inorganic fine particles having a small particle diameter of 5 to 50 nm are added and mixed. An image forming method, characterized in that the toner is formed of

In order to achieve the above object, in the toner for developing an electrostatic image of the present invention, first, at least the colored resin particles have a volume average particle size of 50 nm to 1000 nm, and the triboelectrification property with the triboelectrification member is the same as that of the colored particles. By adding polar organic fine particles, the fine particles are fixed on the surface of the colored particles at an immobilization rate of 10 to 90%, and then the volume average particle diameter is further 5 to 50 n.
The inorganic fine particles of m are externally added and mixed.

The manufacturing method for obtaining the toner is characterized in that after the fixing step of the colored particles and the large-sized organic fine particles, the external addition mixing step is carried out, and the coloring particles at the fixing step. When the glass transition temperature of the resin is Tg, Tg-
It is preferable that the temperature of the colored particles in the external addition mixing step is within the temperature range of 20 ≦ fixing treatment temperature ≦ Tg + 20, and the temperature range of the externally added mixing temperature is Tg−20 ≧ external addition mixing temperature. In the present invention, the peripheral speed of the stirring blade during mixing preferably satisfies the relationship of 10 m / sec ≦ fixing treatment speed ≦ externally added mixing speed ≦ 40 m / sec. In addition, it is preferable to hold for 1 min.ltoreq.holding time.ltoreq.60 min within the processing temperature range during the immobilization step. Furthermore, the stirring peripheral speed during the external additive mixing step is set to V
(M / sec), and when the mixing time is T (sec), the treatment is preferably performed in the range of 2000 (m) ≦ V · T ≦ 8000 (m).

Conventionally, when an external additive having a large particle size is fixed to a toner using a soft resin, when inorganic fine particles having high hardness are used, the stress relaxation ability is low and the difference in specific gravity is large, so that the colored particles are colored. It may be detached from the surface and cause a scratch on the drum between the blade and the photoconductor during cleaning. On the other hand, when organic fine particles having a hardness relatively close to that of toner are used, they are softer than inorganic fine particles, so that the ability to relieve stress becomes large and the difference in specific gravity is small, so the desorption in the developing device And scratches during cleaning are improved.

However, the organic fine particles generally have a large charge retention ability, and the charge accumulated on the fine particles hardly leaks, so that the distribution of the charges on the surface of the colored particles becomes uneven. In particular, when organic particles having a polarity opposite to that of colored particles are used, electrostatic attraction between toner particles causes electrostatic cohesion, causing repelling at the time of transfer and deterioration of fluidity, resulting in toner coagulation in the toner hopper. Due to poor replenishment and poor mixing with the carrier, the rise of charging may be reduced, causing problems such as fog.

Therefore, in the present invention, organic particles having the same polarity as the colored particles are used as the external additive having a large particle size to be immobilized. As a result, the distribution of electric charges on the surface of the colored particles can be made uniform, and electrostatic repulsion can be applied between the toner particles. As a result, it is possible to obtain extremely excellent flow characteristics by externally adding the inorganic fine particles having a small particle size in the external addition and mixing step after fixing.

Further, in the manufacturing method of the present invention, in the fixing step of the colored particles and the large-sized organic fine particles, when the glass transition temperature of the resin of the colored particles is Tg under the condition of small mechanical impact force. And Tg-20 ≤ immobilization temperature ≤ T
By stirring and mixing in the material temperature range of g + 20,
The external additive fine particles suitably attached to the surface of the colored particles can be easily and softly immobilized without being released. Further, at the fixing temperature, 1 (min) ≦ holding time ≦ 60
By holding in the range of (min), the fine particles can be uniformly fixed on the surface of the colored particles. The mixture in this state is clearly different from the conventional mixture in that no white float originating from the released large-sized organic fine particles is observed.

In the external additive mixing step, after the material temperature is cooled to Tg-20 ≧ external additive mixing temperature, the mechanical impact force is made higher than in the fixing step, and the treatment is carried out to obtain colored particles and a small particle size. In addition to the electrostatic frictional force with the inorganic fine particles, a mechanochemical effect and a crushing effect of small-sized inorganic fine particles into primary particles are added, and as a result, the inorganic fine particles are densely dispersed on the surface of the colored particles, A mixture having excellent fluidity can be obtained in a short time. Further, since it can be carried out in the same apparatus, a toner having excellent performance can be easily obtained in a short time.

The present invention will be specifically described below.

In the present invention, organic fine particles having the same charging property as the colored particles are used as the external additive having a large particle size to be immobilized as described above. This charging property is measured by, for example, Dowa Iron Powder Co., Ltd., specific gravity 5.0, weight average particle diameter 60 μm, Cu—Zn ferrite iron having a saturation magnetization of 62 emu / g when an external magnetic field of 1000 oersted is applied. Powder, and either the colored particles or the immobilized fine particles are weighed at 19.0 g and 1.0 g, respectively, and 20 CC
Put iron powder and evaluation particles in this order in a sample bottle at 25 ℃, 5
Leave overnight at 0-60% RH environmental conditions. Then, using a shaker (Yayoi type New-YS), the mixture was mixed for 20 minutes at a swing angle of 30 ° and a shaking rate of 200 strokes / min, and then, using an aluminum cell having a 400 mesh screen, a blow pressure of 0. 6 at 2 kg / cm ²
The amount of electric charge when blow-off for sec is measured.

By fixing the external additive of the same polarity, it is possible to make the charge distribution on the surface of the colored particles uniform, suppress electrostatic aggregation between toners, and flow after external addition and mixing. It becomes possible to improve the property. The triboelectric charge amount of the organic fine particles is preferably in the range of 20 to 200 μC / g.

Further, when the large-sized inorganic fine particles are fixed, the fixing is uniformly achieved, but the detachment occurs due to the stress in the developing device, and the drum scratches occur due to the cleaning. .

As the large particle size organic fine particles, those having a particle size of 50 nm or more are preferably used in order to exert the above-mentioned excellent effects. When the particle size is 50 nm or less, the effect of suppressing the embedding, which is a feature of the large particle diameter external additive, cannot be obtained, and the particles are completely buried by immobilization. Further, it is impossible to completely immobilize a substance having a thickness of 1000 nm or more, and even if the treatment is carried out in the above temperature range, it cannot be sufficiently achieved.

As the inorganic fine particles having a small particle diameter, it is preferable to use those having a particle diameter of 5 to 50 nm in order to exert the fluidity effect more. If it is 50 nm or more, the effect of improving the fluidity is not sufficient, and if it is not fixed, desorption occurs, free external additive migrates to the carrier and causes charge amount fluctuation, drum damage and blade damage. To become.
If it is 5 nm or less, it is difficult to disperse it uniformly in the primary particles, which may cause black spots.

Further, the manufacturing method of the present invention is characterized in that the colored particles and the fine particles are fixed under a specific condition and then the external additive is mixed, and in the fixing step, a stirring condition with a small mechanical impact force is used. And the material temperature is Tg-20 ≦
It is preferable to increase the immobilization temperature to Tg + 20 so that the particles can be easily and softly immobilized without releasing the fine particles suitably attached to the surface of the colored particles.

The state of this fixing is B of the external additive and the toner.
From the ET specific surface area, the degree of immobilization Fd as defined by the following formula was defined.

[0032]

[Equation 1]

Fd: Degree of fixation (%) Fixed toner Sw: BET specific surface area (m of fixed toner)
² / g) Untreated toner Sw: BET specific surface area of untreated toner (m
² / g) Added external additive Sw: BET specific surface area of added external additive (m ² / g) The BET specific surface area is Flow manufactured by Shimadzu Corporation.
It is measured by the BET one-point method using sorb 2300.

When the temperature range is lower than Tg-20 ° C., the degree of immobilization Fd may not reach 10%. At this time, the large-sized organic fine particles simply adhere to the surface of the colored particles. This is a state, and the large-sized organic fine particles are released to cause the above-mentioned problems. On the other hand, when the temperature is higher than Tg + 20 ° C., the degree of immobilization Fd exceeds 90%, the large-sized organic fine particles are excessively fixed, the influence on the surface of the colored particles becomes large, and the effect of suppressing burial disappears. Further, thermal coagulation occurs between the toner particles, the particle size distribution changes, the charge amount changes, and toner scattering and image deterioration occur.

On the other hand, when the stirring impeller peripheral speed is set to be higher than 40 m / s and the mechanical impact force is increased at a temperature lower than Tg-20 ° C. to treat the particles, the large-sized organic fine particles adhere and fix. As a result, the crushing / desorption / dispersion effect is greatly exerted, and uniform and sufficient immobilization tends not to be achieved.

Further, by holding at the fixing temperature in the range of 1 min ≦ holding time ≦ 60 min, the large-sized organic fine particles can be fixed more uniformly and firmly on the surface of the colored particles.

In the present invention, when all of the above conditions are satisfied, stable chargeability and high and stable transferability are maintained for a long period of time, and excellent developer performance is exhibited. If any of these conditions is out of the range, the above-mentioned problems may occur to some extent, and a developer having desired performance may not be obtained sufficiently.

The toner used in the present invention is a toner obtained by adding the fine particles of the present invention to colored particles containing a binder resin, a colorant, and other additives used as necessary. The average particle size is a volume average particle size and is usually 1 to 30 μm.
m, preferably 5 to 15 μm. The binder resin that constitutes the colored particles is not particularly limited, and various conventionally known resins can be used. For example, a styrene resin, an acrylic resin, a styrene / acrylic resin, a polyester resin, and the like can be given. Here, the glass transition temperature of the resin is 45 to 70 for improving fixing property and blocking property.
C., preferably 52 to 65.degree. When the temperature is low, the fine particles are fixed well, but the blocking property is deteriorated, which may cause problems such as agglomeration and fusion of the toner to the carrier inside the developing device. On the other hand, when the glass transition temperature is high, the problem of blocking does not occur, but the adhesiveness to paper is deteriorated and the fixing property is sometimes deteriorated.

The colorant is not particularly limited, and carbon black, nigrosine dye, aniline blue, calcoil blue, chrome yellow, ultramarine blue, DuPont oil red, quinoline yellow, methylene blue chloride, which are known for conventional color toners, Examples include phthalocyanine blue, malachite green oxalate, and rose bengal. For example, carbon black, nigrosine dye, or the like is used as the black toner, and C.I. I. Pigment Blue 15: 3, C.I. I.
Pigment Blue 15, C.I. I. Pigment Blue 1
5: 6, C.I. I. Pigment Blue 68, C.I. I. Pigment Red 48-3, C.I. I. Pigment Red 12
2, C.I. I. Pigment Red 212, C.I. I. Pigment Red 57-1, C.I. I. Pigment Yellow 1
7, C.I. I. Pigment Yellow 81, C.I. I. Pigment Yellow 154 and the like can be preferably used.

Examples of other additives include charge control agents such as salicylic acid derivatives and azo metal complexes, and fixability improving agents such as low molecular weight polyolefins and carnauba wax.

The composition of the organic fine particles constituting the present invention is not particularly limited. Generally, vinyl-based organic fine particles are preferable. The reason for this is that it can be easily produced by a production method such as an emulsion polymerization method or a suspension polymerization method. Specifically, 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-octyl styrene, pn-nonyl styrene,
styrene or styrene derivative such as pn-decylstyrene, pn-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,
Methacrylic acid ester derivatives such as diethylaminoethyl methacrylate and dimethylaminoethyl methacrylate, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, n-octyl acrylate. ,
Polymers such as acrylic acid ester derivatives such as 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, phenyl acrylate, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, and the like can be mentioned as materials for forming the organic fine particles. . These can be used alone or in combination.

Further, as materials for constituting other vinyl resin fine particles, olefins such as ethylene, propylene and isobutylene, halogen vinyls such as vinyl chloride, vinylidene chloride, vinyl bromide and vinyl fluoride, Vinyl esters such as vinyl propionate, vinyl acetate and vinyl benzoate, vinyl ethers such as vinyl methyl ether and vinyl ethyl ether, vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone and vinyl hexyl ketone, N-vinylcarbazole, N -N-vinyl compounds such as vinylindole and N-vinylpyrrolidone, vinyl compounds such as vinylnaphthalene and vinylpyridine, acrylonitrile, methacrylonitrile, acrylamide, N-butylacrylamide, N, N-dibutylacrylamide Methacrylamide, N- methacrylamide, there are acrylic acid or methacrylic acid derivatives such as N- octadecyl acrylamide. These vinyl-based monomers may be used alone or in combination to form a polymer.

Further, the organic fine particles need to be stable even when the developer is used for a long period of time. For this purpose, it is preferable to cross-link the resin organic fine particles themselves with various cross-linking agents and use them as those having high hardness. Examples of the crosslinking agent include divinylbenzene, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, and the like. The amount of the crosslinking agent used is appropriately adjusted depending on the required degree of crosslinking, and is preferably used in an amount of 0.1 to 5% by weight based on the vinyl monomer. If the amount of the cross-linking agent is too high, the hardness becomes high, but it becomes brittle, and on the contrary, the durability is deteriorated. If the amount of the cross-linking agent added is too small, the effect of the cross-linking agent cannot be exhibited.

The organic fine particles can be produced by an emulsion polymerization method or a suspension polymerization method. Emulsion polymerization method is a method in which the monomer is added to water containing a surfactant to emulsify and then polymerized, and as the surfactant, sodium dodecylbenzene sulfonate, polyvinyl alcohol, ethylene oxide adduct, and higher Any substance used as a surfactant such as alcohol sodium sulfate can be used and is not particularly limited. Furthermore, the use of a reactive emulsifier, a hydrophilic monomer, for example, polymerization with a persulfate initiator such as vinyl acetate or methyl acrylate, a method of copolymerizing a water-soluble monomer, a water-soluble resin or A so-called non-emulsion polymerization method such as a method using an oligomer, a method using a decomposable emulsifier, a method using a cross-linking emulsifier is also suitable. Examples of reactive emulsifiers include sulfonates of acrylic acid amides and salts of maleic acid derivatives. The emulsion-free polymerization method has no influence of the residual emulsifier and is suitable when organic fine particles are used alone.

The polymerization initiator necessary for synthesizing the organic fine particles includes peroxides such as benzoyl peroxide and lauryl peroxide, and azo polymerization initiation such as azobisisobutyronitrile and azobisisovaleronitrile. Agent. The addition amount of these is preferably 0.1 to 2% by weight with respect to the monomer. If the amount is less than this amount, the polymerization reaction will be insufficient and a problem of residual monomer itself will occur. Further, if the amount is too large, the decomposition product of the polymerization initiator remains and affects the charging property, and further, the polymerization reaction is too fast, which causes a problem that the molecular weight becomes small. Furthermore, in the emulsion polymerization method or the like, potassium persulfate, sodium thiosulfate or the like can be used as a polymerization initiator.

On the other hand, various inorganic oxides, nitrides, borides and the like are preferably used as the inorganic fine particles for constituting the present invention. For example, silica, alumina, titania,
Zirconia, barium titanate, aluminum titanate, strontium titanate, magnesium titanate,
Cerium oxide, zinc oxide, chromium oxide, cerium oxide,
Examples thereof include antimony oxide, tungsten oxide, tin oxide, tellurium oxide, manganese oxide, boron oxide, silicon carbide, boron carbide, titanium carbide, silicon nitride, titanium nitride and boron nitride. Further, the inorganic fine particles may be subjected to a hydrophobic treatment. When performing the hydrophobic treatment, it is preferable to perform the hydrophobic treatment with a so-called coupling agent such as various titanium coupling agents and silane coupling agents, and further higher fatty acids such as aluminum stearate, zinc stearate and calcium stearate. Those subjected to a hydrophobic treatment with a metal salt are also preferably used.

Examples of materials for hydrophobizing include tetrabutyl titanate, tetraoctyl titanate, isopropyl triisostearoyl titanate, isopropyl tridecylbenzene sulfonyl titanate, and bis (dioctyl pyrophosphate) oxyacetate as titanium coupling agents. There are titanates. Further, as the silane coupling agent, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ-
(2-Aminoethyl) aminopropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-β- (N-vinylbenzylaminoethyl) γ-
Aminopropyltrimethoxysilane hydrochloride, hexamethyldisilazane, methyltrimethoxysilane, butyltrimethoxysilane, isobutyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, dodecyltrimethoxysilane, phenyltri Examples thereof include methoxysilane, o-methylphenyltrimethoxysilane, p-methylphenyltrimethoxysilane and the like.

Further, silicone oil obtained by amino-modifying polysiloxane can also be used. An example of this is γ- (2-aminoethyl) with respect to polysiloxane.
Examples include those treated with aminopropylmethyldimethoxysilane.

Examples of the fatty acid and its metal salt include undecyl acid, lauric acid, tridecyl acid, dodecyl acid, myristic acid, palmitic acid, pentadecyl acid, stearic acid, heptadecyl acid, arachidic acid, montanic acid, oleic acid, linoleic acid, Examples include long-chain fatty acids such as arachidonic acid, and their metal salts include zinc, iron, magnesium,
Salts with metals such as aluminum, calcium, sodium, lithium and the like can be mentioned.

These compounds are preferably added in an amount of 1 to 10% by weight based on the weight of the inorganic fine particles, and are preferably coated.
It is 3 to 7% by weight. Further, these materials can be used in combination.

The amount of the inorganic fine particles added is preferably about 0.1 to 5.0% by weight with respect to the toner. If the addition amount is too small, the effect of improving the transferability, which is the object of the present invention, does not occur, and if it is too large, problems such as scratches on the photoconductor due to release of the added fine particles and poor conveyance of the developer occur.

In the present invention, as a method for immobilizing fine particles on the surface of colored particles, Tg-20 ≦ (stirring / mixing temperature) ≦ for preventing separation of the external additive having a large particle diameter, as described above.
It is preferable to stir and mix the resin particles and the external additive under the condition of Tg + 20 to uniformly fix the external additive on the surface of the resin particles while applying mechanical impact force. As a specific device, a Henschel mixer, a V-type mixer, a Loedige mixer, a Nauter mixer, a W cone mixer, a Vibro mill, or the like can be used. Among them, the Henschel mixer can be suitably used from the viewpoints that the mixing treatment of the external additive and the fixing treatment can be carried out by the same apparatus, and that the stirring and mixing are easy and the heating from the outside is easy.

As a method for controlling the temperature, it is preferable to adjust the temperature to the required temperature by using hot water or the like from the outside. At this time, the method of measuring the temperature is to measure the temperature of a portion where the toner is flowing while the toner is being stirred and mixed. Further, after that, it is preferable that cold water is circulated after the fixing treatment to perform a cooling step.

Further, in the present invention, since all treatments are carried out by the same stirring and mixing apparatus, it is possible to immobilize two or more kinds of fine particles at the same time or separately. In addition, the external addition and mixing of small-sized inorganic fine particles is added after the fixing treatment of organic fine particles,
Mixing is preferred.

A method of forming an image on the photoreceptor may be a method of forming an image by contact development, and in the case of forming a color image, an image is repeatedly formed on the photoreceptor without contact with a developer. Alternatively, a method of forming a full-color image may be used, or a method of forming one color on the photoconductor in a contact or non-contact state, sequentially transferring from the photoconductor to the intermediate transfer body, and forming a full-color image on the intermediate transfer body may be used. .

When developing in a non-contact state, it is preferable to convey the developer by a thin layer forming method. The thin layer forming method is 20 to 500 μm in the developing area on the surface of the developer carrier.
The method of forming the developer layer of is shown. When forming this thin layer, there are a magnetic blade that uses a magnetic force and a method of pressing a developer layer restriction rod against the surface of the developer carrying member. Further, there is also a method of contacting a surface of a developer bearing member with a urethane blade, a phosphor bronze plate or the like to regulate the developer layer.

As the developer carrying member, a developing device in which a magnet is built in the carrying member is used, and as the developer carrying member surface, aluminum or aluminum whose surface is oxidized, or stainless steel is used. To be

The pressing force of the pressing regulating member is 1 to 15 g
f / mm is preferred. When the pressing force is small, the regulation force is insufficient and the conveyance becomes unstable. On the other hand, when the pressing force is large, the stress on the developer increases, and the durability of the developer decreases. A more preferred range is 3
10 to 10 gf / mm.

The gap between the developer bearing member and the surface of the photosensitive member needs to be larger than the developer layer, and the gap is smaller than that of the developer layer.
The width is preferably 0 μm or more. A particularly preferable range is 15 to 200 μm. Further, it is preferable to apply an AC bias as an alternating electric field in addition to a DC component as a developing bias. 1000-300 as an alternating electric field
0 Hz, and the voltage is preferably 500 to 2000 V in absolute value from peak to peak (Vp-p). If it exceeds this range, the effect of pulling back the weakly chargeable toner, which is the effect of the alternating electric field, may not be sufficiently exerted, and if it is smaller than this range, the action of the alternating electric field may not be exerted.

The size of the developer carrying member is 10 in diameter.
Those having a size of ４０40 mm are preferred. If the diameter is small, the mixing of the developer is insufficient, and it becomes difficult to ensure sufficient mixing to impart charge to the toner, and if the diameter is large, the centrifugal force against the developer becomes large, Cause the problem of splattering.

An example of the non-contact developing system will be described below with reference to FIG.

FIG. 1 is a schematic view of a developing section of a non-contact developing system which can be suitably used in the image forming method of the present invention. 1 is a photoconductor, 2 is a developer carrier, and 3 is the toner of the present invention. The contained two-component developer, 4 is a developer layer regulating member, 5 is a developing region, 6 is a developer layer, and 7 is a power source for forming an alternating electric field.

The two-component developer containing the toner of the present invention is carried by the magnetic force on the developer carrying member 2 having the magnet 2B therein, and is carried to the developing area 5 by the movement of the developing sleeve 2A. At the time of this conveyance, the thickness of the developer layer 6 is regulated by the developer layer regulating member 4 so as not to come into contact with the photoconductor 1 in the developing area 5.

The minimum gap (Dsd) of the developing area 5 is the thickness of the developer layer 6 conveyed to that area (preferably 20 to 5).
00 μm), for example, about 100 to 1000 μm. The power source 7 for forming the alternating electric field is preferably an alternating current having a frequency of 1 to 10 kHz and a voltage of 1 to 3 kVp-p. The power supply 7 may have a configuration in which direct current is added in series to alternating current as necessary. DC voltage is 100 to 800
V is preferred.

The image forming method of the present invention will be described in detail below with reference to FIGS.

As the developer carrying member used in the present invention, as shown in FIG. 1, one having a magnet 2B built in the carrying member is used, and the sleeve 2A constituting the surface of the developer carrying member is used. Aluminum, aluminum whose surface is oxidized, or stainless steel is used.

An example of the sequential transfer method shown in FIG. 2 will be described below.

Reference numeral 11 is a charging device which is a charging electrode, and 12 is a developing unit which is a developing device for loading yellow, magenta, cyan and black toners, respectively, and is divided into four containers corresponding to four color toners. . The basic configuration of these developing units is the same as the schematic diagram of the developing unit shown in FIG. Reference numeral 14 is a photoconductor drum, 13 is a cleaning unit, 15 is a transfer drum carrying a recording material for transferring a monochromatic color toner image formed on the photoconductor drum, and a monochromatic color is successively printed on the recording material carried thereon. The toner image is transferred and finally a desired multicolor image is formed. Reference numeral 16 is a transport unit for transporting a recording material on which a toner image on the transfer drum is transferred, 17 is an inside of the transfer drum 15, and an adsorption electrode for electrostatically attracting the recording material to the drum by corona discharge from the inside. , 18 are transfer electrodes for sequentially transferring the toner image formed on the photosensitive drum 14 to the transfer drum 15, and 19
Is a peeling electrode for peeling off the recording material electrostatically adsorbed on the transfer drum 15, and 20 is a removing electrode for removing the electric charge remaining on the transfer drum after the recording material is peeled off.

Electric charges are uniformly formed on the photosensitive drum 14 by the charging electrode 11, and thereafter, imagewise exposure (means not shown) is performed to form an electrostatic latent image. This electrostatic latent image is developed by a developing unit in the developing unit 12 that holds a toner of one color (for example, black toner), and a toner image of one color is formed on the photosensitive drum 14. On the other hand, the recording material conveyed to the transfer drum 15 by the conveying unit 16 is the adsorption electrode 1
It is electrostatically adsorbed on the transfer drum by 7 and conveyed to the transfer section.

The transfer electrode 18 is applied to the conveyed recording material.
Then, the toner image formed on the photoconductor drum 14 is transferred. After the toner image is transferred, the toner remains on the photosensitive drum 14, and the residual toner is cleaned by the cleaning unit 13 and used in the next process. In the case of forming a multicolor image, toner images of other colors are formed by development according to the same process and transferred one by one onto the recording material on the transfer drum 15. Finally, the desired toner image is transferred onto the transfer drum 15.
It is formed on the recording material that is adsorbed on top. The recording material carrying the desired toner image is peeled off by the peeling electrode 19 (the peeling electrode 19 is kept inactive until this stage) and is conveyed to the fixing section to obtain the final fixed multicolor toner image. To be On the other hand, the transfer drum 15 removes the remaining charges by the removal electrode 20 and is used in the next process. The movement of the recording material in both FIGS. 2 and 3 is indicated by a large arrow.

Next, the batch transfer method will be described with reference to FIG.

The description of each part of the apparatus is the same as the example of FIG. However, 10 is a transport unit that transports the toner image while transporting the transported recording material. An electric charge is uniformly formed on the photosensitive drum 14 by a charging electrode, and then an electrostatic latent image is formed by a latent image forming means (not shown). This electrostatic latent image is developed by a developing unit in the developing unit 12 that holds a toner of one color (for example, black toner), and a toner image of one color is formed on the photosensitive drum.
In this example, this toner image is not transferred,
On the photoconductor drum having the toner image as it is, charge is again uniformly formed by the charging electrode 11, an electrostatic latent image is further formed, and the electrostatic latent image is developed by a developing device having toner of a color different from the above. , Toner images of other colors are formed by being superimposed on the previous toner image. During this time, the cleaning unit 13, the transfer electrode 18, and the transport unit 10 are retracted from the photoconductor drum 14 so as not to operate or disturb the toner image on the photoconductor drum 14.

After the desired image formation is completed and a multi-color toner image is formed, the toner image on the photosensitive drum is conveyed by the conveying unit 16 and then on the recording material conveyed by the conveying section 10. Is transferred by the transfer electrode 18. The recording material carrying the transferred toner image is conveyed to the fixing portion and fixed, and a final multicolor toner image is formed on the recording material. Since the untransferred toner remains on the photosensitive drum 14 after the transfer of the toner image, it is cleaned by the cleaning unit 13 and used in the next process.

The toner image formed on the photosensitive drum by the various methods described above is transferred to a recording material such as paper in a transfer process. The transfer method is not particularly limited, and various methods such as so-called corona transfer method and roller transfer method can be adopted.

In the fixing step used in the present invention, a roller fixing method can be used as an example.

[0076]

The present invention will be described in detail below with reference to examples, but the embodiments of the present invention are not limited thereto.

[Production Example of Colored Particles] (Colored Particles 1) Component Weight Part Polyester Resin (Glass Transition Temperature = 57 ° C.) 100 Carbon Black 10 Polypropylene 2 The above components are kneaded, ground and classified to obtain a volume average particle size of 8. 5μ
m colored particles were obtained. This is referred to as “colored particle 1”.
(Amount of charge: −25.2 μC / g) (Colored particles 2) Component weight part Styrene / acrylic resin (glass transition temperature = 50 ° C.) 100 Carbon black 10 Polypropylene 2 The above components are kneaded, pulverized, classified, and the volume average is obtained. Particle size 8.5μ
m colored particles were obtained. This is referred to as “colored particles 2”.
(Charge amount: +19.3 μC / g) [Production example of added fine particles] (Fixed fine particles 1) Nylon (nylon 6) resin fine particles (volume average particle diameter 200 n
m) was used.

Charge amount: +160 μC / g (immobilized fine particles 2) PVDF produced by emulsion polymerization
Fine particles of (polyvinylidene fluoride) (volume average particle diameter 150 nm) were used.

Charge amount: -195 μC / g (Fixed fine particles 3) Styrene resin fine particles (volume average particle diameter 400 nm) prepared by emulsion polymerization were used.

Charge amount: +16.5 μC / g (immobilized fine particles 4) dry silica (volume average particle diameter 70 n
m) 100 g of hexamethyldisilazane was stirred in methanol for 30 minutes, filtered, dried, and then crushed to prepare.

Charge amount: -120 μC / g (fine particles for external addition 1) dry silica (volume average particle diameter 15 n
m) was prepared in the same manner as the immobilized fine particles 4.

(Fine Particles for External Addition 2) Amorphous titania (volume average particle diameter 30 nm) was prepared by treating with 10 g of C ₁₀ H ₂₁ Si (OCH ₃ ) _{3 in} the same manner as for the immobilized fine particles 4. .

As a method for measuring the particle size of the fine particles, the particle size distribution was measured with a particle size distribution measuring device ELS-800 (manufactured by Otsuka Electronics Co., Ltd.) to obtain the volume average particle size.

[Method for Measuring Charge Amount of Colored Particles and Immobilized Fine Particles] Dowa Iron Powder Co., Ltd., specific gravity 5.0, weight average particle diameter 60 μm, saturation magnetization when an external magnetic field of 1000 oersted was applied of 62 emu / g of Cu-Zn ferrite iron powder and 19.0 g and 1.0 g of each of the colored particles or the immobilized fine particles are weighed, and the iron powder and the evaluation particles are placed in this order in a 20 CC sample bottle at 25 ° C and 50 ° C. ~
Leave overnight at 60% RH environmental conditions. Then, using a shaker (Yayoi New-YS), after mixing for 20 minutes at a swing angle of 30 ° and a shaking rate of 200 strokes / min,
Blow-off method, i.e., using an aluminum cell with a 400 mesh screen, blow pressure 0.2
Blow-off was carried out at 6 kg / cm ^{2 for} 6 seconds, and the charge amount was measured.

[Toner Production Example] The colored particles and the fine particles were premixed using a Mitsui Henschel mixer (FM-10B), and then warm water was circulated through the jacket, and the peripheral speed, time and heating rate were set under the conditions shown in Table 1. Was variously changed to obtain the toner of the present invention. The conditions and characteristics are shown below.

[0086]

[Table 1]

Immobilization degree: FL manufactured by Shimadzu Corporation mentioned above
The colored particles, the added fine particles and the treated toner were measured by the BET one-point method using OWSORB 2300, and the value of the degree of immobilization was calculated.

[Developer Production Example] (Production Method of Carrier) Specific Gravity 5.0, Weight Average Particle Diameter 40 μ
m, a copolymer of MMA / St (methylmethacrylate / styrene) = 6/4 composition or silicone on the surface of Cu—Zn ferrite particles having a saturation magnetization of 62 emu / g when an external magnetic field of 1000 oersted is applied. The resin was prepared so that the average film thickness of the coating layer was 2.0 μm.

(Developer manufacturing method) 558 g of the above carrier
And 42 g of each toner in Table 1 using a V-type mixer under a test environment (20 ° C .; 50% RH).
A developer was prepared by mixing for 0 minutes.

(For colored particles 1, MMA / S
For the t = 6/4 composition copolymer and the colored particles 2, a carrier coated with a silicone resin was used. [Evaluation of Toner and Developer] The toner and the developer produced by the above-mentioned method were tested on an actual machine after the degree of immobilization and the charge buildup of the developer were evaluated.

(Evaluation of actual machine) The evaluation is carried out by a color copying machine Koni manufactured by Konica Co., Ltd., which is a non-contact development batch transfer method in which all the colors are superposed on the photoconductor and then collectively transferred to the transfer paper.
The ca9028 was modified and used. The main conditions are shown below. A laminated organic photoreceptor was used as the photoreceptor.

Photoconductor surface potential = -550V DC bias = -250V AC bias = Vp-p: -50 to -450V Alternating electric field frequency = 1800Hz Closest distance (Dsd) = 300 between the developer carrier and the photoreceptor
μm Pressing control force = 10gf / mm Pressing control rod = SUS416 (magnetic stainless steel) /
Diameter 3 mm Developer layer thickness = 150 μm Developer carrier diameter = 20 mm (Evaluation item, method) N. Environmental conditions (2
0 ° C; 50% R.C. H. ), A live-action film evaluation of 1000
0 copy was performed, the amount of charge at the initial stage and after copying 10,000 copies, fog, toner solidification in the toner box, transfer repellency,
The black spot was evaluated.

(1) Rise of developer charge: The charge rise performance was obtained by measuring the charge amount 1 minute and 20 minutes after the start of mixing of the mixture described in the developer manufacturing method by the blow-off method and taking the ratio thereof. (2) Charge amount: A durability test was conducted on an actual machine, and the charge amount of the initial developer and the charge amount at the end of 10,000 copies were measured by the blow-off method. (3) Fog occurrence: image sample The image defects due to fog were evaluated (4) Toner cohesiveness: confirmed by the number of copies in which replenishment defects due to toner aggregation in the hopper occurred (5) Transfer crater: Image defects due to cissing were evaluated from the image sample. (6) Black spots: Image defects of black spots were evaluated due to the influence of agglomerates of free external additives generated on the photoconductor (Evaluation results). It was carried out to prepare a developer in the toner. Table 2 shows the results.

[0094]

[Table 2]

It can be seen that the toners 1 to 6 for practical use in the present invention have all good characteristics and are highly practical, while the toners 1 to 5 for comparison have a problem in at least one of the characteristics.

[0096]

EFFECTS OF THE INVENTION According to the present invention, the particle size on the surface of colored particles is 5
By adding externally mixed small-sized inorganic fine particles having a particle size of 5 to 50 nm to a toner in which large-sized organic fine particles having a chargeability of the same polarity as the colored particles having a particle size of 0 nm to 1000 nm are softly fixed, A toner for electrostatic charge development, which has stable chargeability for a long period of time without desorption of organic fine particles of size, high and stable transfer characteristics, and can obtain a good image with excellent fluidity without fog or transfer cissing. provide.

[Brief description of drawings]

FIG. 1 is a schematic view of a developing unit showing an example of a non-contact developing system used in the present invention.

FIG. 2 is a sectional view of an image forming apparatus showing an example of a sequential transfer method used in the present invention.

FIG. 3 is a sectional view of an image forming apparatus showing an example of a batch transfer method used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Developer carrier 12 Development unit 13 Cleaning unit 14 Photoconductor drum 15 Transfer drum 18 Transfer electrode

Claims (6)

[Claims] 1. A toner for developing an electrostatic charge image comprising fine particles added to and mixed with colored particles comprising at least a resin and a colorant, wherein the toner has a volume average particle size of 50 to 1000.
nm, the organic particles having triboelectricity with the triboelectrification member and having the same polarity as the colored particles are fixed on the surface of the colored particles, and then inorganic fine particles having a volume average particle size of 5 to 50 nm are added and mixed. Characteristic toner for developing electrostatic image. 2. A method for producing a toner for developing an electrostatic charge image, comprising adding fine particles to colored particles comprising at least a resin and a colorant, wherein the toner has a volume average particle diameter of 50 to 50.
An organic fine particle having a triboelectrification property with the triboelectrification member having the same polarity as that of the colored particle at 1000 nm is fixed on the surface of the colored particle, and then inorganic fine particles having a volume average particle size of 5 to 50 nm are added and mixed. A method for producing a toner for developing an electrostatic charge image. 3. The fixing step and the external additive mixing step are carried out in the same apparatus, and the temperature of the colored particles in the fixing step is Tg−20 (° C.) ≦ fixing when the glass transition temperature of the resin is Tg. After being kept for at least 1 (min) ≦ holding time ≦ 60 (min) in the temperature range of chemical treatment temperature ≦ Tg + 20 (° C.), external addition is performed in the temperature range of Tg−20 (° C.) ≧ external addition mixing temperature. The method for producing a toner according to claim 2, wherein an agent mixing step is performed. 4. The electrostatic charge according to claim 3, wherein the tip peripheral speed of the stirring blade of the mixer during the immobilization step and the external additive mixing step is treated in the following speed range. Method for producing toner for image development. 10 (m / sec) ≦ fixing step ≦ external additive mixing step ≦ 4
0 (m / sec) 5. The stirring peripheral speed during the external additive mixing step is V (m /
sec) and the mixing time is T (sec), the process is carried out within the following range, and the method for producing an electrostatic image developing toner according to claim 3. 2000 (m) ≦ V · T ≦ 8000 (m) 6. An electrostatic latent image is obtained by using a developing device containing a magnet for a developer composed of a toner for developing an electrostatic image and a carrier prepared by adding and mixing fine particles to colored particles composed of at least a resin and a colorant. In an image forming method of developing an electrostatic latent image formed on a forming member, the toner has a volume average particle diameter of 50 to 1000 nm and an organic material having a triboelectric chargeability with the triboelectric charging member having the same polarity as that of the colored particles. An image forming method, characterized in that fine particles are fixed on the surface of colored particles, and then inorganic fine particles having a small volume average particle diameter of 5 to 50 nm are further added and mixed.