JP2000275907A - Electrostatic latent image developing toner and its production, electrostatic latent image developer using the same and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an excellent image having excellent aging stability and free from the fogging of the image or transfer defeat without causing the deterio ration of dielectric loss and electrostatic charge. SOLUTION: The electrostatic latent image developing toner has 2.0-9.0 μm volume average particle diameter D50, volume average particle size distribution index GSDv of <=1.28, the average value of 105-150 in the shape factor SF expressed by a relation; SF=ML2/A×100, and <=5.0% area ratio of pores in the cross-section. In the relation, ML represents the max. length in the projected image of the electrostatic latent image developing toner and A represents the projected surface area in the projected image of the electrostatic latent image developing toner.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic latent image developing toner used for developing an electrostatic latent image in electrophotography and electrostatic recording, a method for producing the same, and an electrostatic latent image developing method. The present invention relates to an electrostatic latent image developer using a toner for image forming and an image forming method.

[0002]

2. Description of the Related Art In electrophotography, an electrostatic latent image formed on a photoreceptor (electrostatic latent image carrier) is formed by a toner for developing an electrostatic latent image containing a colorant (hereinafter simply referred to as "toner"). ), And the obtained toner image is transferred onto a transfer paper and fixed with a hot roll or the like to obtain an image. The photoconductor is cleaned again to form an electrostatic latent image. Dry developers used in such electrophotography are roughly classified into one-component developers using a toner itself in which a colorant is dispersed in a binder resin, and two-component developers using a carrier mixed with the toner. When a copying operation is performed using these developers, the developer must have excellent fluidity, transportability, fixability, chargeability, and transferability for process compatibility. is necessary.

[0003] Toner particles in a developer (hereinafter, the main part of the toner, that is, a part other than the external additives in the toner may be particularly referred to as "toner particles") are usually produced by a kneading and pulverizing method. . In this kneading and pulverizing method, a thermoplastic resin or the like is melt-kneaded together with a pigment, a charge controlling agent, a release agent such as wax, and the like, and after cooling, the melt-kneaded product is finely pulverized.
This is a method of producing desired toner particles by classification.

[0004] In recent years, Japanese Patent Application Laid-Open No.
No. 282752 and JP-A-6-250439 propose an emulsion polymerization aggregation method. In the emulsion polymerization aggregation method, a resin dispersion liquid is prepared by emulsion polymerization, while a colorant dispersion liquid in which a colorant is dispersed in a solvent is prepared, and these are mixed to form aggregated particles corresponding to the toner particle diameter. After that, the toner particles are fused by heating to obtain toner particles. According to this emulsion polymerization aggregation method, the toner shape can be arbitrarily controlled from an irregular shape to a spherical shape by selecting a heating temperature condition.

[0005] In addition, in an emulsion aggregation polymerization method or the like, by adding a resin dispersion liquid in multiple stages, it is possible to wrap and cover a colorant and a release agent, and to improve powder characteristics. It is.

When toner particles are produced by the above-mentioned emulsion aggregation polymerization method, bubbles are generated due to the surfactant used in the stage of aggregation while stirring in a dispersion liquid in which resin particles and a colorant are dispersed. There are cases. The bubbles disappear in the late stage of the aggregation, but the bubbles may be taken into the toner as it is depending on the conditions at the time of preparing the toner. When the aggregation and coalescence proceed as they are, voids are generated inside the toner. Surfactant, water, and the like remain in these pores, which is expected to cause deterioration of the dielectric loss factor and deterioration of charging. The deterioration of the dielectric loss rate and the deterioration of the charging deteriorate the stability over time, and may cause fogging and transfer failure of the obtained image.

[0007]

According to the present invention, it is possible to obtain a good image which is excellent in stability over time and free from image fog and transfer failure without causing deterioration of the dielectric loss factor and deterioration of charging. Electrostatic latent image developing toner and method for producing the same,
Another object of the present invention is to provide an electrostatic latent image developer using the electrostatic latent image developing toner and an image forming method.

[0008]

Means for Solving the Problems The present inventors diligently studied the chargeability and dielectric properties of the toner, and found the relationship between the pores present in the toner and the above-mentioned characteristics. By controlling the amount to a certain amount or less, a toner excellent in chargeability and dielectric property could be provided.

That is, according to the present invention, the volume average particle size D ₅₀ is in the range of 2.0 to 9.0 μm, the volume average particle size distribution index GSDv is 1.28 or less, and is represented by the following (formula 1). An electrostatic latent image developing toner, wherein an average value of the shape factor SF is in a range of 105 to 150, and an area ratio of pores in a cross section is 5.0% or less; And an electrostatic latent image developer and an image forming method using the electrostatic latent image developing toner.

SF = ML ² / A × 100 (Formula 1) ML: Maximum length of the projected image of the electrostatic latent image developing toner A: Projected area of the projected image of the electrostatic latent image developing toner

According to the present invention, since a toner having a good shape and powder characteristics as obtained by an emulsion aggregation polymerization method and having a small number of pores in the toner, a surfactant is contained in the toner. Deterioration of the dielectric loss factor and deterioration of electrification caused by the remaining water and water do not occur.
Therefore, it is possible to obtain a good image which is excellent in stability over time and free from image fogging and transfer failure. In particular,
It is easy to make the dielectric loss factor 100 or less.

The toner for developing an electrostatic latent image according to the present invention is obtained by dispersing a resin particle and a colorant in an aqueous medium, an organic solvent, or a mixed solvent thereof, and stirring the resin particle and the colorant while stirring the dispersion. It is preferable that the agent is produced by agglomeration and coalescence of the agent and granulated, and it is preferable that the agent further contains a release agent. Further, the number average particle diameter of the resin particles is preferably 0.5 μm or less, and the average dispersion particle diameter of the colorant is preferably in the range of 100 nm to 500 nm, and the resin particles and the colorant are aggregated. It is preferable to further add a dispersion liquid in which resin fine particles are dispersed when the particles are combined and granulated. After the resin particles and the colorant are agglomerated, it is also preferable that the resin particles and the colorant are further covered with a resin and united.

The toner for developing an electrostatic latent image according to the present invention includes:
The charge amount is preferably in the range of -40 to -10 [mu] C / g. The electrostatic latent image developing toner of the present invention is an aqueous medium,
An organic solvent, or a dispersion step of dispersing the resin particles and the colorant in a mixed solvent thereof, and a granulation step of aggregating and coalescing the resin particles and the colorant while stirring the dispersion to form a granulation step. Can be manufactured by selecting conditions, for example, adding resin fine particles further in the granulation step, and further using metal as an aggregating agent in the granulation step. It can be produced by adding a compound.

The electrostatic latent image developing toner of the present invention is used as an electrostatic latent image developing toner in an electrostatic latent image developer comprising a carrier and an electrostatic latent image developing toner. Preferably has a resin film layer.

[0015] The toner for developing an electrostatic latent image of the present invention comprises a latent image forming step of forming an electrostatic latent image on an electrostatic latent image carrier, and a developer layer on the developer carrier. A developing step of developing the electrostatic latent image formed on the carrier to form a toner image, and a transfer step of transferring the toner image onto a transfer body,
In the image forming method, the developer can be contained in the developer layer. Preferably, the image forming method further includes, after the transfer step, a cleaning step for removing and collecting the toner remaining on the electrostatic latent image carrier, and the toner removed and collected in the cleaning step is developed again. It is desirable to supply to the process.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a description will be given of the area ratio of voids in a cross section of a toner characteristic of the present invention.

Area ratio of voids in cross section of toner (%)
Refers to a cross section of the toner observed with a microscope or the like and a percentage of the occupied pores in the total area of the cross section, and in the present invention, 10 samples indiscriminately extracted from the toner to be measured. Is referred to as “area ratio of voids in the cross section of the toner”. Of course, it is preferable that the average of the values measured for more samples is included in the scope of the present invention.

Specifically, after obtaining a photograph of the cross section of the toner using a TEM or the like, the image is analyzed using an image analyzer (for example, Luzex manufactured by Nireco) or the like, and the area is measured by directly measuring the area. be able to. In addition, the following simple measurement method can be adopted.

<Simplified Method for Measuring Area Ratio of Voids in Toner Cross Section> The obtained photograph of the cross section of the toner is copied on a tracing paper or the like, the toner portion is cut out, and the weight of the cut tracing paper is measured. . Thereafter, the holes are cut off, and the weight of the cut-out tracing paper is measured. Since each of the obtained weights corresponds to the ratio of the area, the area ratio (%) of the pores in the cross section of the toner can be obtained from these values.

The area ratio of voids in the cross section of the toner is essential to be 5% or less, preferably 4.
0% or less, more preferably 3.0% or less. If it exceeds 5%, the number of pores in the toner increases, and a surfactant or water may be left inside the toner, which may cause deterioration of the dielectric loss factor or deterioration of charging.

The volume average particle diameter D ₅₀ of the toner of the present invention is:
2.0 to 9.0 μm, preferably 3.0 to 9.0 μm.
It is in the range of 8.0 μm. When the volume average particle diameter D ₅₀ is more than 9.0 .mu.m, without being developed toner particles faithfully to the latent image dots and lines, there is a case reproduction or the reproduction of thin lines of a photographic image is poor. On the other hand, the volume average particle diameter D ₅₀
Is less than 2.0 μm, the toner surface area per unit becomes large, and it becomes difficult to control charging and toner fluidity, so that a stable image may not be obtained.

Here, the volume average particle diameter D ₅₀ of the toner means a particle diameter at which the cumulative volume becomes 50% from the smaller diameter side. For example, Coulter Counter TA-II (manufactured by Nikkaki Co., Ltd.), Multisizer II ( (Manufactured by Nikkaki Co., Ltd.).

In the present invention, the average particle size distribution index GSDv of the toner is 1.28 or less, preferably 1.25.
It is as follows. When the ratio exceeds 1.28, it is difficult to simultaneously achieve high image quality and high reliability. That is, the life of the toner or the developer containing the toner is shortened, and the resolving power is apt to decrease. Furthermore, selective development is likely to occur, and the developability may deteriorate over time.

Here, the average particle size distribution index GSDv of the toner
The, for the particle diameter D _84v which cumulative volume becomes 84% from the small diameter side, the ratio of the particle diameter D _16v of the cumulative volume becomes 16% (D
Refers to the square root of _84v / D _16v), the volume average particle diameter D ₅₀
Can be measured using the same device as described above. In the present invention, the average value of the shape factor SF of the toner is 105 to 15
A range of 0, preferably a range of 105 to 135, more preferably a range of 105 to 130 is suitable because it is advantageous in terms of image forming properties, toner productivity and the like.

Here, the shape factor SF of the toner is represented by the following (formula 1). SF = ML ² / A × 100 (Formula 1) ML: Maximum length of the projected image of the electrostatic latent image developing toner A: Projected area of the projected image of the electrostatic latent image developing toner The value measured and calculated as follows is the average value of the toner shape factor SF.

<Method of Measuring Average Value of Toner Shape Factor SF> Toner to be measured is sprayed on a slide glass,
The optical microscope screen was taken into an image analyzer (Lusex, manufactured by Nireco) using a video camera, and the maximum length and the projected area of the projected image of 100 samples indiscriminately extracted were measured. It is obtained by calculating the coefficient SF and obtaining the average value. Of course, it is preferable that the average of the values measured for more samples is included in the scope of the present invention.

[0027] The toner of the present invention has good dielectric properties and chargeability by the above constitution. Here, the dielectric properties of the toner, particularly the dielectric loss factor (generally, “specific dielectric loss factor”
) Can be measured by the following method.

<Measurement Method of Dielectric Loss Factor> 5 g of toner powder to be measured is put into a mold having a diameter of 5 cm, and a load of 10 tons is molded for 1 minute.
Installed on METER dielectric measurement electrode, JIS K6
The measurement is performed under the condition of a frequency of 1 kHz by the method described in 911. The dielectric loss factor is an index indicating the resistance of a dielectric substance placed under an AC electric field, and it is known that the larger the value, the lower the resistance. The toner of the present invention can reduce the dielectric loss factor by adopting the above configuration. The dielectric loss factor is preferably 100 or less,
More preferably, it is 50 or less. If the dielectric loss factor exceeds 100, fogging due to charge injection may occur in the transfer step, which is not preferable.

As a method for obtaining the toner of the present invention, any method can be used as long as it satisfies the above-defined shape, particle size and void area ratio. For example, in the melt-kneading pulverization method, a well-known sphering treatment may be performed after performing a precise classification so as to obtain a sharp particle size distribution.

In order to obtain a toner having the above-defined shape and particle size, resin particles and a colorant are dispersed in an aqueous medium, an organic solvent, or a mixed solvent thereof, and the dispersion is stirred. It is preferable to employ an emulsion aggregation polymerization method in which the resin particles and the colorant are aggregated and coalesced while being granulated to produce a toner. More specifically, a polymerizable monomer of a binder resin is emulsion-polymerized to obtain a dispersion of resin particles, and the dispersion and a colorant, and, if necessary, a release agent, a charge control agent, and the like. Are mixed, aggregated, and fused by heating to unite to obtain toner particles.

The emulsion aggregation polymerization method will be described in detail below. Examples of the binder resin used include styrenes such as styrene and chlorostyrene, monoolefins such as ethylene, propylene, butylene and isoprene, vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate and vinyl butyrate, and methyl acrylate. Α-methylene aliphatic monocarboxylic esters such as ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate, vinyl methyl Examples include vinyl ethers such as ether, vinyl ethyl ether and vinyl butyl ether, vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and vinyl isopropenyl ketone, and homopolymers and copolymers thereof. Polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-anhydride Maleic acid copolymer, polyethylene, polypropylene and the like can be mentioned. Further, polyester, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, paraffin wax and the like can be mentioned.

Of these resins, vinyl resins are particularly preferred. In the case of a vinyl resin, by polymerizing a vinyl monomer by a method such as emulsion polymerization or seed polymerization using an ionic surfactant or the like, a resin particle dispersion can be easily prepared. It is advantageous. In the case of other resins, if the resin is soluble in a solvent that is oily and has a relatively low solubility in water, dissolve the resin in those solvents and use it in a dispersing machine such as a homogenizer together with an ionic surfactant or a polymer electrolyte. The resin particle dispersion can be prepared by dispersing the fine particles in the solvent and then heating or reducing the pressure to evaporate the solvent.

The number average particle diameter of the resin particles obtained by emulsion polymerization of the polymerizable monomer of the binder resin is preferably 0.5 μm or less, more preferably 0.01 to 0.1 μm.
5 μm range, more preferably 0.01 to 0.3 μm
Range. When the number average particle diameter of the resin particles exceeds 0.5 μm, it becomes easy to form pores in the finally obtained toner for developing an electrostatic latent image.

Examples of the coloring agent include carbon black, chrome yellow, Hansa yellow, benzidine yellow, selenium yellow, quinoline yellow, permanent orange GTR, pyrazolone orange, vulcan orange, watch young red, permanent red, brilliantamine 3B, and brilliant. Carmine 6B, Dupont Oil Red, Pyrazolone Red, Risor Red, Rhodamine B Lake, Lake Red C, Rose Bengal, Aniline Blue, Ultramarine Blue, Calco Oil Blue, Methylene Blue Chloride, Phthalocyanine Blue, Phthalocyanine Green, Malachite Green Oxalate, Various pigments such as acridine, xanthene, azo, benzoquinone, azine, anthraquinone, thioin Co, dioxazine, thiazine, azomethine, indico, thioindico, phthalocyanine, aniline black, polymethine, triphenylmethane, diphenylmethane, thiazine, thiazole, and xanthene dyes. These can be used alone or in combination of two or more.

The average dispersed particle diameter of the colorant is 100
It is preferably in the range of nm to 500 nm, more preferably in the range of 100 nm to 300 nm. 100
If it is less than nm, the coloring power tends to decrease, and a large amount of a colorant dispersion is required, which tends to adversely affect the increase in free colorant and the shape controllability of the toner.
Not preferred. On the other hand, when the thickness exceeds 500 nm, the coloring agent becomes difficult to be taken into the toner, and is likely to cause liberation.

The toner of the present invention may optionally contain a charge controlling agent or a release agent (offset preventing agent). Known charge control agents can be used. For example, azo metal complex compounds, metal complex compounds of salicylic acid, and resin type charge control agents containing polar groups can be used. In the case of producing a toner by a wet process such as an emulsion aggregation polymerization method, a material that is hardly dissolved in water is preferable in terms of ionic strength control and wastewater contamination.

Examples of the release agent include waxes such as low molecular weight polypropylene and low molecular weight polyethylene. The release agent is dispersed in the form of dispersed particles in the dispersion, and is mixed with the resin particle dispersion, the colorant dispersion, and the like. The average dispersed particle diameter of the release agent is from 0.01 μm to
It is preferably in the range of 1.0 μm, more preferably in the range of 0.1 μm to 0.5 μm.

A magnetic material can be further included in the toner to form a magnetic toner, but a non-magnetic toner containing no magnetic material can also be used.

The dispersion medium in the resin particle dispersion, the colorant dispersion and the dispersion obtained by dispersing the other components (particles) includes an aqueous medium, an organic solvent, and a mixed solvent thereof.

As the aqueous medium, for example, distilled water,
Water such as ion-exchanged water is included. Examples of the organic solvent include water-miscible alcohols such as ethanol and methanol, n-propanol, ethylene glycol, glycerin, and i-propanol, and acetic acid and alcohol ketones. These may be used alone or in combination of two or more.

Examples of surfactants that can be used for emulsion polymerization, colorant dispersion, dispersion and aggregation of resin particles and release agents, or stabilization of these are, for example, sulfate ester salts and sulfonate salts. Anionic surfactants such as phosphate-based, phosphate-based, and soap-based, cationic surfactants such as amine-based and quaternary ammonium salt-based, or polyethylene glycol-based, alkylphenol-ethylene oxide adduct-based, and polyhydric alcohol-based Nonionic surfactants and the like are mentioned, and it is also effective to use them in combination.

As a means for dispersing the colorant, the resin particles, or the release agent, a general disperser such as a ball mill, a sand mill, and a dyno mill having a rotary shearing homogenizer or a medium can be used.

Each of the dispersions obtained above is mixed, and if necessary, a known coagulant is added for coagulation, followed by heating and fusing to obtain toner particles. The heat fusion may be performed at a temperature equal to or higher than the glass transition temperature of the resin contained in the aggregated particles and lower than the decomposition temperature. By appropriately selecting the heating temperature, the shape of the obtained toner particles can be controlled from an irregular shape to a spherical shape. The time required for heat fusion depends on the heating temperature, and is generally in the range of 30 minutes to 10 hours.

Further, after the resin particles and the colorant are aggregated but before they are coalesced, the above-mentioned resin particles are further added and mixed and coated with a resin, so that the toner obtained after the coalescence is subjected to a core-shell process. A structure is also possible.

The toner particle dispersion after the coalescence and granulation is filtered, and the toner particles are collected by filtration. The filtered toner particles are washed with ion-exchanged water or the like. The washing is performed by heating ion-exchanged water or the like in which the toner particles are dispersed as necessary. Since the toner particle dispersion before filtration is usually shifted toward the acid side, it is preferable to adjust the dispersion to the alkaline side during washing. Adjustment to the alkali side is performed by adding a suitable alkali, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium hydrogen carbonate, ammonia and the like.

If the pH after the adjustment is about 7 to 13, there is a difference in the effect, and the effect of cleaning the toner particles is exhibited. However, there is no practical problem within the above range, but when the pH is less than 9, the effect on improving the charging characteristics is slightly small, and the stability of the toner particles is slightly lacked when the substrate is washed by heating at a high temperature. On the other hand, if the pH is higher than 12, the effect of removing the surfactant remaining in the toner is certainly large, but the detachment of the toner particles, for example, the colorant particles and the release agent particles, also increases. , Lacks good chargeability and stable reproduction of fixability. Therefore, the pH after adjustment is preferably in the range of 9 to 12. The washed toner particles are filtered again, sufficiently washed with ion-exchanged water or the like, and then dried to obtain a final toner.

As described above, in the emulsion aggregation polymerization method, bubbles may be generated in the step of aggregating the resin particles and the colorant. In some cases, it may be difficult to set "rate". In order to suppress the amount of vacancies to a predetermined value, it is conceivable to take a long time for coagulation or to adjust the dispersion method at the stage of preparing the dispersion.

In the present invention, it is preferable to employ any one of the following methods (1) to (4) in order to suppress the amount of vacancies to a predetermined value. An antifoaming agent is added before or at the time of mixing each dispersion. By the presence of the defoaming agent, bubbles existing at the stage of mixing the respective dispersions can be effectively eliminated, and the amount of pores of the finally obtained toner can be suppressed to a predetermined value.

The defoaming agent that can be used is not particularly limited, and includes alcohols such as methanol, ethanol, and isopropyl alcohol, silicone oils, and the like. An antifoam can be used.

The amount of the defoaming agent to be added may be appropriately set depending on the type of the defoaming agent and the surfactant used and the amount of foam. For example, in the case of alcohols, the respective dispersions are mixed. It is preferably 0.5 to 10% by weight, more preferably 1.0 to 5.0% by weight, based on the liquid (hereinafter sometimes referred to as "dispersed mixed liquid") after silicone oils. Is preferably 1 to 200 ppm, more preferably 5 to 100 ppm, based on the dispersion mixture.

At the time of mixing the respective dispersions, resin fine particles made of the same resin as the resin particles and having a smaller particle size than the resin particles are added. By adding the resin fine particles, the resin fine particles fill the voids, and the amount of the voids of the finally obtained toner can be suppressed to a predetermined value. The resin fine particles are made of the same resin as the resin particles, but have a number average particle size of preferably 0.10 μm or less, more preferably 0.07 μm or less. The lower limit of the number average particle size of the resin fine particles is not particularly set as the smaller the particle size, the more effectively the pores are filled. However, the lower limit is about 0.01 μm in terms of production suitability.

The amount of the fine resin particles to be added may be appropriately set depending on the type of the resin.
It is preferably 10% by weight, more preferably 5 to 8% by weight.

A metal compound (including “metal compound polymer”) is used as an aggregating agent. The use of an aggregating agent such as a metal compound having a strong aggregating power is effective in reducing the porosity of the toner because the aggregating becomes dense. This metal compound is preferably used by dissolving it in a resin particle dispersion.

The metal elements constituting the metal compound are 2A, 3A, 4A, 5A, 6A, 7A, and 2A in the long-term periodic table.
It has two or more valence charges belonging to groups 8, 1B, 2B, and 3B, and dissolves in an ionic state in an aggregate system of resin particles. Specifically, calcium chloride,
Metal salts such as calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, aluminum sulfate, and iron (III) hydroxide; and metal compound polymers such as polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide Can be mentioned.

The amount of the metal compound added is preferably in the range of 0.05 to 0.30% by weight, more preferably 0.10 to 0.2% by weight, based on the coagulated dispersion (dispersion mixture).
It is in the range of 5% by weight.

Either of the above-mentioned methods can provide a toner having a vacancy amount specified in the present invention.
By combining these methods, a toner having an even smaller amount of pores can be obtained.

The toner of the present invention may have inorganic powder particles adhered to the surface according to the purpose. Known inorganic powder particles can be used. For example, silica, alumina, titania, calcium carbonate, magnesium carbonate,
Examples thereof include calcium phosphate, cerium oxide, and metatitanic acid. The surface of the inorganic powder particles may be subjected to a known surface treatment depending on the purpose.

The charge amount of the toner of the present invention when used is preferably in the range of −40 to −10 μC / g, more preferably in the range of −30 to −15 μC / g. When the charge amount is less than −40 μC / g, it causes a decrease in density, and when the charge amount exceeds −10 μC / g, it causes fogging.

In the present invention, the charge amount of the toner refers to the charge amount after mixing the toner and the carrier after mixing the external additives, and specifically, the charge amount of the toner and the carrier at normal temperature and normal humidity. Is placed in a glass bottle having a capacity of 50 ml, shaken with a turbuler mixer for 2 minutes, and then measured using a blow-off tribo apparatus (manufactured by Toshiba Chemical Corporation).

The toner of the present invention obtained as described above can be used as it is as a one-component developer or an electrostatic latent image developer comprising a carrier and a toner for developing an electrostatic latent image (so-called two-component developer). Can be used as a toner for developing an electrostatic latent image.

The carrier is not particularly limited.
Known carriers can be used. For example, a resin-coated carrier having a resin coating layer on a core material can be mentioned. Alternatively, a resin dispersion type carrier in which a conductive material or the like is dispersed in a matrix resin may be used.

As the coating resin / matrix resin used for the carrier, polyethylene, polypropylene, polystyrene, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral,
Polyvinyl chloride, polyvinyl carbazole, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic acid copolymer, straight silicone resin comprising organosiloxane bond or a modified product thereof, fluororesin, polyester, polyurethane,
Examples thereof include polycarbonate, phenol resin, amino resin, melamine resin, benzoguanamine resin, urea resin, amide resin, and epoxy resin, but are not limited thereto.

Examples of the conductive material include metals such as gold, silver and copper, carbon black, titanium oxide, zinc oxide, barium sulfate, aluminum borate, potassium titanate, and the like.
Examples include tin oxide and carbon black, but are not limited thereto.

Examples of the core material of the carrier include magnetic metals such as iron, nickel, and cobalt; magnetic oxides such as ferrite and magnetite; and glass beads. It is preferred that The volume average particle size of the core material of the carrier is generally 10 to 500 μm, preferably 3 to 500 μm.
0 to 100 μm.

In order to coat the surface of the core material of the carrier with a resin, there is a method of coating with the coating resin and, if necessary, a solution for forming a coating layer in which various additives are dissolved in an appropriate solvent. The solvent is not particularly limited, and may be appropriately selected in consideration of the coating resin to be used, suitability for application, and the like.

Specific examples of the resin coating method include a dipping method in which a carrier core material is dipped in a coating layer forming solution, a spray method in which a coating layer forming solution is sprayed on the surface of the carrier core material, and a carrier core material. The fluidized bed method of spraying a coating layer forming solution in a state of being floated by flowing air, mixing the carrier core material and the coating layer forming solution in a kneader coater,
A kneader coater method for removing the solvent may be used.

The thus-obtained electrostatic latent image developer is subjected to a latent image forming step of forming an electrostatic latent image on the electrostatic latent image carrier and the developer layer on the developer carrier to form the electrostatic latent image developer. An image forming method including: a developing step of developing an electrostatic latent image formed on an electrostatic latent image carrier to form a toner image; and a transfer step of transferring the toner image onto a transfer body. Provided for layer formation.

As the electrostatic latent image carrier, a general electrophotographic photosensitive member, a dielectric recording medium or the like is used, and an electrostatic latent image is formed by a known method. As the developer carrier, for example,
A magnetic roller fixedly installed in a rotatable non-magnetic sleeve is used, and the developer carrier is arranged so as to face the electrostatic latent image carrier. The toner image formed on the electrostatic latent image carrier is then transferred onto the transfer body by a known method, and is fixed by a fixing unit such as a hot roll.

Since the toner of the present invention has a high transfer efficiency, it can be applied to a so-called cleaningless system having no cleaning step after the transfer step. In this case, the slightly remaining toner on the electrostatic latent image carrier is collected by the developer carrier at the same time as the development.

On the other hand, it is preferable to have a cleaning step of removing and collecting the toner remaining on the electrostatic latent image carrier after the transfer step. In this case, the toner removed and recovered in the cleaning step can be supplied to the developing step again, thereby contributing to resource saving.

[0071]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

<Preparation of resin particle dispersion> a) Preparation of resin particle dispersion (1) styrene 370 parts by weight n-butyl acrylate 30 parts by weight acrylic acid 8 parts by weight dodecanethiol 24 parts by weight tetrabromide 4 parts by weight of carbon

The above materials were mixed and dissolved. This is treated with a nonionic surfactant (Nonipol 4 manufactured by Sanyo Chemical Industries, Ltd.).
00) 6 parts by weight and 10 parts by weight of an anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC) were added to a solution of 550 parts by weight of ion-exchanged water, emulsified in a flask, and slowly emulsified for 10 minutes. While mixing with water, a solution obtained by dissolving 4 parts by weight of ammonium persulfate in 500 parts by weight of ion-exchanged water was added thereto, and after purging with nitrogen, the oil was stirred until the contents reached 70 ° C. while stirring the inside of the flask. The mixture was heated in a bath, and emulsion polymerization was continued for 5 hours. As a result, a resin particle dispersion liquid (1) obtained by dispersing resin particles having a number average particle size of 155 nm, a Tg of 59 ° C., and a weight average molecular weight (Mw) of 12,000 was obtained.

B) Preparation of Resin Particle Dispersion (2) ・ Styrene 370 parts by weight ・ n-butyl acrylate 30 parts by weight ・ Acrylic acid 8 parts by weight ・ Dodecanethiol 24 parts by weight ・ Carbon tetrabromide 4 parts by weight

The above materials were mixed and dissolved. This is treated with a nonionic surfactant (Nonipol 4 manufactured by Sanyo Chemical Industries, Ltd.).
00) 6 parts by weight and 10 parts by weight of an anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC) are added to a solution of 880 parts by weight of ion-exchanged water, emulsified in a flask, and slowly stirred for 10 minutes. While mixing with water, a solution obtained by dissolving 4 parts by weight of ammonium persulfate in 500 parts by weight of ion-exchanged water was added thereto, and after purging with nitrogen, the oil was stirred until the contents reached 70 ° C. while stirring the inside of the flask. The mixture was heated in a bath, and emulsion polymerization was continued for 5 hours. As a result, a resin particle dispersion (2) obtained by dispersing resin particles having a number average particle diameter of 75 nm, a Tg of 53 ° C., and a weight average molecular weight (Mw) of 18,000 was obtained.

C) Preparation of resin particle dispersion (3): 360 parts by weight of styrene 40 parts by weight of n-butyl acrylate 6 parts by weight of methacrylic acid

The above materials were mixed and dissolved. This is treated with a nonionic surfactant (Nonipol 4 manufactured by Sanyo Chemical Industries, Ltd.).
00) 8 parts by weight and 15 parts by weight of an anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd .: Neogen R) were added to a solution of 660 parts by weight of ion-exchanged water, emulsified in a flask, and slowly emulsified for 10 minutes. While mixing with water, a solution prepared by dissolving 3 parts by weight of ammonium persulfate in 500 parts by weight of ion-exchanged water was added thereto, and after purging with nitrogen, the contents of the flask were stirred until the contents reached 70 ° C. The mixture was heated in a bath, and emulsion polymerization was continued for 5 hours. As a result, a resin particle dispersion (3) obtained by dispersing resin particles having a number average particle size of 165 nm, a Tg of 58 ° C., and a weight average molecular weight (Mw) of 33,000 was obtained.

<Preparation of Colorant Dispersion> a) Preparation of Colorant Dispersion (1): 50 parts by weight of carbon black (manufactured by Cabot: Mogal L); anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd.) Manufactured by: Neogen R) 5 parts by weight ・ Ion-exchanged water 200 parts by weight

The above materials are mixed, and further dispersed using a homogenizer (Ultra Turrax T50 manufactured by IKA) for 20 minutes, and a colorant (carbon black) having an average dispersed particle diameter of 160 nm is dispersed. Dispersion (1) was prepared.

B) Preparation of Colorant Dispersion (2) 50 parts by weight of phthalocyanine pigment (PB-FAST BLUE, manufactured by BASF) Anionic surfactant (Neogen R, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 5 Parts by weight ・ 200 parts by weight of ion-exchanged water

The above materials are mixed, and further dispersed using a homogenizer (Ultra Turrax T50, manufactured by IKA) for 10 minutes, and a color dispersant (2) obtained by dispersing a blue pigment having an average dispersed particle size of 150 nm is dispersed. Was prepared.

<Preparation of Release Agent Dispersion> 50 parts by weight of paraffin wax (manufactured by Nippon Seiro Co., Ltd .: HNP0190) 10 parts by weight of anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC) 240 parts by weight ion-exchanged water

The above materials are mixed and heated to 95 ° C.
Homogenizer (IKA: Ultra Turrax T5)
After dispersing using the method (0), the mixture was subjected to a dispersion treatment using a pressure discharge homogenizer to prepare a release agent dispersion in which a release agent having an average dispersed particle diameter of 200 nm was dispersed.

Example 1 <Preparation of Agglomerated Particles> 120 parts by weight of resin particle dispersion (1) 80 parts by weight of resin particle dispersion (2) 200 parts by weight of colorant dispersion (1) 200 parts by weight Release 40 parts by weight of agent dispersion liquid (1) 1.5 parts by weight of polyaluminum hydroxide (made by Asada Chemical Co., Ltd.)

The above materials were homogenized in a round stainless steel flask (Ultra Turrax T by IKA).
After mixing and dispersing using (50), the flask was heated to 55 ° C. in a heating oil bath while stirring the inside of the flask. Here, 35 parts by weight of ethanol was added dropwise as an antifoaming agent since the viscosity increased with the generation of foam. After that, a decrease in viscosity was confirmed. When a small sample was collected and the particle size was measured using Multisizer II (manufactured by Nikkaki Co., Ltd.), aggregated particles having a number average particle size of about 4.8 μm were formed. It was confirmed that it was done.

<Preparation of Adhered Particles> To the liquid containing the obtained aggregated particles, 50 parts by weight of the resin particle dispersion liquid (1) was gently added, and the mixture was kept at 55 ° C. for 60 minutes. When a small sample was collected and the particle size was measured using Multisizer II (manufactured by Nikkaki Co., Ltd.), it was confirmed that adhered particles having a number average particle size of about 5.0 μm were formed.

<Preparation of Toner> An anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was added to the obtained liquid containing the adhered particles.
Neogen SC) 3 parts by weight, heated to 95 ℃,
Hold for 6 hours. After cooling, sodium hydroxide was added to adjust the pH to 11.5, washed at 40 ° C. for 15 minutes, filtered, thoroughly washed with ion-exchanged water and dried to obtain a volume average particle diameter D ₅₀ = 4. .8 μm, volume average particle size distribution index GS
Black toner particles having Dv = 1.20 and an average shape factor SF of 130 were obtained. R972 is added to the toner particles.
(Silica; manufactured by Nippon Aerosil Co., Ltd.) was added with a 0.65 wt% Henschel mixer to obtain a black toner.

Example 2 <Preparation of Agglomerated Particles> 200 parts by weight of resin particle dispersion (3) 200 parts by weight of colorant dispersion (2) 40 parts by weight of release agent dispersion (1) 40 parts by weight Poly 1.5 parts by weight of aluminum hydroxide (made by Asada Chemical Co., Ltd.)

The above materials were homogenized in a round stainless steel flask (Ultra Turrax T by IKA).
After mixing and dispersing using (50), the flask was heated to 58 ° C. while stirring the inside of the flask in an oil bath for heating. Here, since the viscosity increases with the generation of bubbles, 30 parts by weight of isopropyl alcohol was dropped as an antifoaming agent. After that, a decrease in viscosity was confirmed. When a small sample was collected and the particle size was measured using Multisizer II (manufactured by Nikkaki Co., Ltd.), aggregated particles having a number average particle size of about 5.5 μm were formed. It was confirmed that it was done.

<Preparation of Adhered Particles> To the liquid containing the obtained aggregated particles, 33 parts by weight of the resin particle dispersion (3) was gently added, and the mixture was kept at 58 ° C. for 60 minutes. When a small sample was collected and the particle size was measured with Multisizer II (manufactured by Nikkaki Co., Ltd.), it was confirmed that adhered particles having a number average particle size of about 5.8 μm were formed.

<Preparation of Toner> An anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was added to the obtained liquid containing the adhered particles.
Neogen SC) 3 parts by weight, heated to 95 ℃,
Hold for 6 hours. After cooling, sodium hydroxide was added to adjust the pH to 10.5, and the mixture was washed at 25 ° C. for 15 minutes, collected by filtration, sufficiently washed with ion-exchanged water, and dried to obtain a volume average particle diameter D ₅₀ = 5. .6 μm, volume average particle size distribution index GS
Sian color toner particles having Dv = 1.21 and an average shape factor SF of 128 were obtained. Further, R972 (silica; manufactured by Nippon Aerosil Co., Ltd.) was added to the toner particles in an amount of 0.6%.
A 5 wt% Henschel mixer was added to obtain a Sian toner.

[Example 3] <Preparation of agglomerated particles> 120 parts by weight of resin particle dispersion (1) 80 parts by weight of resin particle dispersion (2) 200 parts by weight of colorant dispersion (1) 200 Fe parts OH) ₃ 1.5 parts by weight

The above materials were placed in a round stainless steel flask in a homogenizer (IKA: Ultra Turrax T).
After mixing and dispersing using (50), the flask was heated to 55 ° C. in a heating oil bath while stirring the inside of the flask. When a small sample was collected and the particle size was measured using a Multisizer II (manufactured by Nikkaki Co., Ltd.), the number average particle size was about 5.0.
It was confirmed that aggregated particles having a size of μm were formed.

<Preparation of Adhered Particles> To the liquid containing the obtained aggregated particles, 50 parts by weight of the resin particle dispersion liquid (1) was slowly added, and the mixture was kept at 55 ° C. for 60 minutes. When a small sample was collected and the particle size was measured with Multisizer II (manufactured by Nikkaki Co., Ltd.), it was confirmed that adhered particles having a number average particle size of about 5.1 μm were formed.

<Preparation of Toner> Including the obtained adhered particles
Add an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .:
Neogen SC) 3 parts by weight, heated to 97 ℃,
Hold for 6 hours. After cooling, adjust the pH to 11.5
After adding sodium hydroxide and washing at 40 ° C. for 15 minutes
Filter again, wash thoroughly with ion exchanged water and dry,
Volume average particle size D ₅₀= 5.2 μm, volume average particle size distribution index
GSDv = 1.21, average value of shape factor SF = 120
Certain black toner particles were obtained. In addition, the toner particles
0.65 with R972 (silica; manufactured by Nippon Aerosil Co., Ltd.)
A black toner was obtained by adding with a wt% Henschel mixer.

Comparative Example 1 <Preparation of Agglomerated Particles> 200 parts by weight of resin particle dispersion (3) 200 parts by weight of colorant dispersion (1) 40 parts by weight of release agent dispersion (1) 40% by weight Cation Surfactant (Sanisol B50, manufactured by Kao Corporation) 1.5 parts by weight

The above materials were homogenized in a round stainless steel flask (Ultra Turrax T by IKA).
After mixing and dispersing using (50), the flask was heated to 55 ° C. in a heating oil bath while stirring the inside of the flask. When a small sample was collected and the particle size was measured using a Multisizer II (manufactured by Nikkaki Co., Ltd.), the number average particle size was about 5.0.
It was confirmed that aggregated particles having a size of μm were formed.

<Preparation of Adhered Particles> To the liquid containing the obtained aggregated particles, 22 parts by weight of the resin particle dispersion (3) was gently added, and the mixture was kept at 55 ° C. for 60 minutes. When a small sample was collected and the particle size was measured using Multisizer II (manufactured by Nikkaki Co., Ltd.), it was confirmed that adhered particles having a number average particle size of about 5.0 μm were formed.

<Preparation of Toner> Anionic surfactant (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) was added to the obtained liquid containing the adhered particles.
Neogen SC) 3 parts by weight, heated to 97 ℃,
Hold for 6 hours. After cooling, sodium hydroxide was added to adjust the pH to 12.0, washed at 45 ° C. for 15 minutes, filtered, sufficiently washed with ion-exchanged water and dried to obtain a volume average particle diameter D ₅₀ = 5. 0.3 μm, volume average particle size distribution index GS
Black toner particles having Dv = 1.23 and an average shape factor SF of 130.0 were obtained. Further, R972 (silica; manufactured by Nippon Aerosil Co., Ltd.) was added to the toner particles at 0.65.
A black toner was obtained by adding with a wt% Henschel mixer.

[Evaluation of Characteristics of Toner] The following evaluations were performed for the obtained toners of the examples and comparative examples. The results are summarized in Table 1 below.

1. The area ratio of pores in the cross section of the toner The area ratio of pores in the cross section of the toner was measured by the above-described <Simple measurement method of the area ratio of the holes in the cross section of the toner>.

2. Chargeability 30 g of a developer (toner content: 5%) composed of a toner and a carrier after mixing with an external additive is placed in a 50 ml-capacity glass bottle at room temperature and normal humidity, and shaken for 2 minutes with a tumbler mixer, and then blow-off The charge amount was measured using a tribo measuring device (manufactured by Toshiba Chemical).

3. Dielectric property The dielectric loss factor was measured by the method described above. The above evaluation results are as shown in Table 1 below.

[0104]

[Table 1]

By setting the area ratio of the holes in the cross section to 5% or less, a toner having good charging characteristics and dielectric characteristics can be obtained.

[Evaluation of Images] With respect to the effects of the dielectric properties and chargeability on the images of the toners of Examples and Comparative Examples, an image was actually formed using (image forming apparatus name), and the fog shown below was obtained. And the stability with time was evaluated.

1. Fog Image formation was performed using a Fuji Xerox Co., Ltd. Vision500 modified machine, and the fog of the background portion was visually observed, and 1 mm
Judgment was made based on the number of particles in ² , and graded in four stages using the following indices. Grade 1: No fog (less than 30 grains / mm ² ). Grade 2: Slight fog, but no practical problem (30 grains / mm ² or more and less than 100 grains / mm ² ). Grade 3: Fog can be visually confirmed, but slight (100
Particles / mm ² or more and less than 200 particles / mm ² ). Grade 4: Fogging can be significantly confirmed visually (200
Grains / mm ² or more).

2. Stability over time Stability over time was determined by measuring the initial charge amount X and the charge amount Y after shaking for 30 hours, and determining the ratio (Y / X). In addition,
The value is practically preferably 0.8 or more. The above evaluation results are as shown in Table 2 below.

[0109]

[Table 2]

A toner having an area ratio of vacancies in the cross section of 5% or less and having good charging characteristics and dielectric characteristics also had good image forming properties.

[0111]

According to the present invention, it is possible to obtain a good image which is excellent in stability over time and free from image fogging and transfer failure without causing deterioration of the dielectric loss factor and deterioration of charging. It is possible to provide an electrostatic latent image developing toner and a method for manufacturing the same, and an electrostatic latent image developer and an image forming method using the electrostatic latent image developing toner.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hisae Yoshizawa 1600 Takematsu, Minami Ashigara City, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Masaaki Suwabe 1600 Takematsu, Minami Ashigara City, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Shuji Sato 1600 Takematsu, Minamiashigara-shi, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Hideo Maehata 1600 Takematsu, Minamiashigara-shi, Kanagawa Prefecture Fuji Xerox Co., Ltd. F-term (reference) 2H005 AB03 BA00 EA05 EA10 FA02

Claims (4)

[Claims] 1. A volume average particle size D ₅₀ of 2.0 to 9.0 μm.
And the volume average particle size distribution index GSDv is 1.2
8 or less, the average value of the shape factor SF represented by the following (Equation 1) is in the range of 105 to 150, and the area ratio of voids in the cross section is 5.0% or less. For developing electrostatic latent images. SF = ML ² / A × 100 (Formula 1) ML: Maximum length in the projected image of the electrostatic latent image developing toner A: Projected area in the projected image of the electrostatic latent image developing toner 2. A dispersion step of dispersing resin particles and a colorant in an aqueous medium, an organic solvent, or a mixed solvent thereof, and aggregating and uniting the resin particles and the colorant while stirring the dispersion. The method for producing a toner for developing an electrostatic latent image according to claim 1, further comprising a granulating step of granulating the toner. 3. An electrostatic latent image developer comprising a carrier and an electrostatic latent image developing toner, wherein the electrostatic latent image developing toner is the electrostatic latent image developing toner according to claim 1. An electrostatic latent image developer comprising: 4. A latent image forming step of forming an electrostatic latent image on an electrostatic latent image carrier, and an electrostatic latent image formed on the electrostatic latent image carrier by a developer layer on the developer carrier 4. An electrostatic latent image according to claim 3, wherein the image forming method includes: a developing step of developing a toner image to form a toner image; and a transfer step of transferring the toner image onto a transfer body. An image forming method characterized by being formed by a developer.