JP2003057872A - Developer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developer which can efficiently raise uniform triboelectric property and can obtain an image of high quality. SOLUTION: The developer contains at least a toner and fine particles prepared by depositing zinc oxide containing different kinds of elements on the surfaces of mother particles. The toner contains at least a binder resin and a coloring agent. The fine particles are present on the toner surface and the mass proportion of the zinc element in the zinc oxide to the mother particles (Zn/mother particles) ranges from >=0.01 to <=2. The molar ratio of the different kinds of elements to the zinc element (different kinds of elements/Zn) ranges from >=0.01 to <=0.3. The fine particles have >=0.1 μm and <5 μm average particle size, contain particles having >=5 μm particle size by <3% in number and have <=1×10<9> Ωcm resistance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developer containing a toner used in a recording method using an electrophotographic method, an electrostatic recording method, a magnetic recording method, a toner jet recording method, or the like. More specifically, the present invention relates to a developer used in a copying machine, a printer or a fax machine, which forms a toner image on an electrostatic latent image carrier in advance and then transfers the toner image onto a transfer material to form an image.

[0002]

2. Description of the Related Art Toner is added with a charge control agent such as a nigrosine dye for imparting a positive property and a metal-containing azo dye for imparting a negative property, for the purpose of obtaining a desired triboelectric charge amount. When a development carrier is used as a two-component developer, it is known to coat the surface of the carrier with a charge control agent.

However, even with the toner to which the charge control agent is applied, the amount of triboelectric charge may fluctuate and the image density may decrease when environmental changes due to humidity and temperature occur or when the toner is durable for a long period of time. In order to improve this, a technique has been proposed in which the toner contains metal oxide fine particles to stabilize the triboelectrification property.

For example, in JP-A-6-175392, a known metal oxide having a volume resistance value of 1 × 10 ⁵ to 1 × 10 ⁸ Ωcm (alumina, zinc oxide, tin oxide, etc.) is used to form a toner. It is added to the coating resin. Alternatively, a reduced form of a metal oxide (Japanese Patent Publication No. 7-113781),
There is also disclosed a technique of externally adding low resistance particles such as antimony-containing tin oxide (Japanese Patent Laid-Open No. 6-118693), carbon black powder, and metal particles to a toner.

[0005]

[Problems to be Solved by the Invention] Alumina, zinc oxide,
Known metal oxides such as tin oxide are 1 × 10 ⁶ to 1 × 10 ⁷ Ωc under the environment of normal temperature and humidity due to the influence of hydroxyl groups on the surface.
It often exhibits a resistance value of about m. However, since the resistance value depends on humidity and the resistance constantly fluctuates, the physical properties may not be stable even when the toner is contained in the toner.

Since tin oxide containing antimony can easily exhibit conductivity by firing in an air atmosphere, resistance variation due to humidity can be prevented, but the fired product exhibits a blue to black blue color. When externally added to the toner, tin oxide released from the toner in the image forming step is transferred to the transfer paper, which causes deterioration in image quality due to color.
Further, addition to the color toner also causes a decrease in color reproducibility.

Oxides which exhibit conductivity by firing a metal oxide such as tin oxide or titanium oxide in a reducing atmosphere such as hydrogen gas to reduce a part of the tin component, or carbon black is Due to the reduction treatment, the fired product becomes blackish and causes the color reproducibility of the toner and the deterioration of the image quality as in the case of tin oxide containing antimony.

A low resistance material such as metal particles lacks long-term stability because it may cause a leak phenomenon in a developing process requiring a high electric field.

Further, these particles have a single particle structure, have high cohesiveness, and often have a broad particle size distribution.
In order to achieve the target particle size and particle size distribution, not only granulation control technology, but also a lot of time is required for mechanical grinding, crushing, classification and other post-processes. Depending on particle size,
In some cases, granulation control may be difficult to cope with, and in the production of small-diameter particles, the efficiency of pulverization and classification may decrease due to the cohesiveness of the particles. When such particles are contained in the toner, the fluidity may become non-uniform, which may cause density fluctuations and image fog during image formation.

[0010]

In the present invention, uniform triboelectrification is efficiently established by whitening, preventing resistance fluctuation, and incorporating fine particles having stable fluidity into the toner. The purpose is to achieve high image quality. The present invention that achieves the object is as follows. (1) In a developer containing at least a toner and fine particles carrying zinc oxide containing a different element on the surface of a mother particle, the toner has at least a binder resin and a colorant, and the fine particles are present on the toner surface. The mass ratio of the zinc element in the zinc oxide to the base particles (Zn / base particles) is 0.01 or more and 2 or less, and the molar ratio of the dissimilar element to the zinc element (dissimilar element / Zn) is 0.001 or more 0 .3 or less, the volume average diameter is 0.1 μm or more and less than 5 μm, the number% of 5 μm or more is less than 3%, and the resistance is 1 × 1.
It is characterized in that it is not more than ⁰⁹ Ωcm. (2) The different element is aluminum, gallium, indium, tin, or germanium. (3) The matrix particles are inorganic particles. (4) The toner has a weight average particle diameter of 3 to 10 μm. (5) The number of fine particles present on the surface of the toner is 0.3 or more per one toner. (6) The ratio (Z / T) of the average diameter Z of the fine particles to the average diameter T of the toner is 0.5 or less. (7) The toner is characterized by containing at least an inorganic fine powder selected from silica, titanium oxide, alumina, or a composite oxide thereof, and having an average primary particle diameter of 4 to 80 nm.

The fine particles of the present invention are white and prevent adverse effects on image quality. Next, the dependence of the resistance value on humidity is prevented, and a stable resistance value as a developer can be maintained. Furthermore, since particles are prevented from coagulating, stable fluidity can be maintained without segregation in the developer. These are peculiar phenomena exhibited by the presence of the fine particles of the present invention on the surface of the toner under specific conditions, and these actions prevent charge-up due to abnormal triboelectric charging under low humidity. In addition, under high humidity, it is possible to prevent the triboelectric charge amount from decreasing due to the moisture absorption of the toner, and to provide stable triboelectric chargeability. Further, since the fluidity of the toner can be improved and made uniform, the triboelectrification property is efficiently raised, and as a result, good image quality can be obtained even after being left for a long period of time. Further, it is possible to obtain effects such as prevention of fusion of the toner component to the photoconductor.

Incidentally, Japanese Patent Application Laid-Open No. 9-111135 discloses that
A technique relating to a composite material in which the surface of white fine powder is coated with aluminum-doped zinc oxide is disclosed. The basic concept of this publication relates to a moldable conductive polymer material obtained by dispersing this composite material in an organic polymer. Further, in Japanese Patent Laid-Open No. 7-291615,
Although zinc-supported spherical silica in which zinc oxide is supported in the pores of spherical silica is disclosed, this publication is a technique utilizing the ultraviolet reflection effect of zinc oxide.

On the other hand, in the present invention, a new effect as a developer is obtained in a special state in which fine particles in a specific state in which the component ratio, particle size distribution, etc. are controlled are present on the surface of the toner, and the abundance ratio is specified. Is what was demonstrated.
Therefore, not only the technical field to which the invention belongs but also the technical idea and configuration are completely different from each other.

[0014]

Embodiments of the present invention will be described below.

(1) Zinc Oxide Fine Particles As a method for producing the zinc oxide fine particles of the present invention, the case where inorganic particles are used as the base particles will be exemplified. For example, a method of coating / impregnating inorganic particles with a mixed solution of a salt compound of zinc and a salt compound of a different element, followed by hydrolysis and then firing, mixing inorganic particles with an aqueous slurry of zinc oxide to which a salt compound of a different element is added. And a method of firing after aging while hydrolyzing. When manufacturing from a zinc oxide slurry, a material that etches (erodes) zinc oxide can be used together. This is because the zinc oxide crystals in the slurry are miniaturized to improve the dispersibility so that the zinc oxide crystals can be efficiently brought into contact with different elements. At the same time, it is also possible to deposit a uniform zinc oxide coating layer on the surface of the inorganic particles regardless of the zinc oxide crystal morphology such as acicular or flaky.

As such an etching agent, a known agent such as a weakly acidic compound or an alkaline compound can be used, but among them, a carbonic acid-based or nitric acid-based ammonia compound that can obtain a stable slurry is preferable.

As the zinc salt compound, a water-soluble inorganic salt or organic salt from which a solution can be obtained is used. Examples of the salts include zinc fluoride, zinc chloride, zinc chlorate, zinc sulfate, zinc nitrate, zinc phosphate, zinc carbonate, zinc cyanide, zinc acetate, zinc oxalate, zinc stearate, potassium potassium sulfate, and sulfuric acid. Examples include zinc ammonium. It is also possible to use a mixture of two or more of these zinc compounds.

As the matrix particles, known particles such as organic particles composed of resin and inorganic particles such as metal or metal compound are used, and among them, inorganic particles are preferable. More preferably, it is a metal oxide or a metal compound containing oxygen, and the metal preferably has a valence of 2 or more. Examples of such particles include titanium oxide, silica, alumina, aluminum silicate, magnesium oxide, tin oxide, barium sulfate, and titanic acid compounds.

For the calcination, a tunnel kiln, a rotary kiln, an electric furnace, a muffle furnace, a vacuum dryer or the like can be used.
The firing atmosphere is an air atmosphere if necessary, an oxidizing atmosphere with an adjusted oxygen partial pressure, a reducing atmosphere into which hydrogen gas or the like is introduced,
An inert atmosphere in which an inert gas is introduced can be adopted.
Above all, a reducing atmosphere that reproducibly exhibits a low resistance value is preferable.

The fine particles of the present invention have a mass ratio (Zn / base particles) of zinc element in zinc oxide to base particles of 0.
It is preferable that the molar ratio of the dissimilar element to the zinc element (dissimilar element / Zn) is adjusted to 01 or more and 2 or less, 0.001 or more and 0.3 or less, and the resistance of the fine particles is adjusted to 1 × 10 ⁹ Ωcm or less.

Here, if the Zn / matrix particle content is less than 0.01, the contact between zinc oxide and the toner is lowered and the triboelectrification imparting ability becomes unstable, while if it exceeds 2, the cohesiveness fluctuates.
The characteristics of the layer structure are not reflected. Also, different elements / Z
When n is less than 0.001, the effect of containing a different element may be drastically reduced and the humidity dependency of the resistance value may be particularly exhibited. On the contrary, when n is more than 0.3, the crystal strength of zinc oxide may change. Mechanical strength may decrease. Further, the resistance value is preferably 1 × 10 ² Ωcm or more and 1 × 10 ⁹ Ωcm.
Or less, more preferably 1 × 10 ² Ωcm or more and 1 ×
It is 10 ⁷ Ωcm or less. If it is less than 1 × 10 ² Ωcm, the developing property may be disturbed at the developing nip portion, and it may be 1 × 10 ⁹ Ω.
If it exceeds cm, charge-up may occur, which is not preferable.

In order to impart the above-mentioned stable resistance and triboelectrification property, different elements such as alkali metal, alkaline earth metal, trivalent Al and In, such as tetravalent Ti, Elements such as Vr, P, and Nb having a valence of 5 such as Zr and Sn are preferably used.

Among these, Al, Ga, In, Sn, and Ge, which can obtain stable conductivity even with a sudden change in humidity.
Is more preferable, and Al is more preferable because the change in resistance with time is suppressed.

In the present invention, other elements may be used in combination so long as such effects are not impaired.

The fine particles of the present invention have a two-layered structure in which zinc oxide containing a different element is supported on the surface of the base particles, and have the characteristic of excellent cohesiveness with the prevention of aggregation between particles. The characteristics are exhibited by adjusting the volume average diameter of 0.1 μm or more and less than 5 μm and the number% of 5 μm or more to less than 3%. Here, it is more preferably 0.3 μm or more and less than 3 μm. If the thickness is less than 0.1 μm, the zinc oxide may not be supported uniformly and the resistance value may fluctuate. If it is 5 μm or more, when used internally, the dispersibility in the binder resin may be reduced and the triboelectrification property may become non-uniform, and when used externally, scattering from the toner causes conspicuous contamination in the machine. Sometimes.

Further, the particle size obtained by measuring the particle size distribution is 5 μm.
The number% of the above particles to the total particles is less than 3%. If it is 3% or more, the triboelectric chargeability may be weaker to start up, or the fluidity of the developer may be partially changed to change the density.

The particle size of the conductive particles of the present invention is measured by adding a liquid module to a LS-230 type laser diffraction type particle size distribution measuring apparatus manufactured by Coulter Co. and measuring 0.04 to 2.
With the particle size of 000 μm as the measurement range, the volume average particle size of the conductive particles, 5% or more in number, is calculated from the obtained volume-based particle size distribution. For the measurement, a trace amount of a surfactant is added to 10 cc of water, 10 mg of conductive particles are added thereto, and the mixture is dispersed for 10 minutes by an ultrasonic disperser, and then the measurement is performed for 90 seconds and the number of measurements is once. It was

To measure the resistance of the fine particles of the present invention, a cylindrical metal cell was filled with about 0.5 g of a sample, electrodes were placed above and below so as to contact the sample, and a load of 147 N was applied to the upper electrode.
(15 kgf) was added. In this state, the voltage V
(50 V) was applied, and the resistance (volume resistivity RV) of the present invention was measured from the current I "A" flowing at that time. In the present invention, the contact area between the electrode and the sample is 2.26 cm ² , the sample thickness M
It is "cm". Here, RV = 100V × 2.26c
m ² / I “A” / M “cm” (unit: Ωcm).

In the developer of the present invention, in order to obtain stable triboelectric chargeability for a long period of time, the number of fine particles present on the toner surface is preferably 0.3 or more per toner, and more preferably. Is 1.0 or more and 50.0 or less per toner. If it is less than 0.3, the effect of improving the fluidity of the toner may be deteriorated, and the triboelectrification distribution may become broad. If it exceeds 50.0, the triboelectrification property may decrease, which is not preferable. Here, examples of the method of incorporating the fine particles into the toner include internal addition and external addition, but external addition is preferable as a mode for performing the above-mentioned action more quickly and efficiently.

The fine particles present on the toner surface are, for example,
It can be confirmed by taking a direct picture of the toner surface. That is, using a scanning electron microscope (SEM), the toner containing fine particles is captured as 10 aggregated toner particles, and the fine particles present on the surface of each toner particle are measured. For the identification of the fine particles, for example, a qualitative analyzer attached to the SEM is used,
This can be done by mapping Zn element. By this method, measurement is performed on 10 aggregates (total of 100 toner particles), and the existence ratio of fine particles per toner particle is calculated.

The fine particles of the present invention have a structure in which zinc oxide containing a different element is supported on the surface of base particles. The qualitative quantification of the constituents can be verified by instrumental analysis such as ICP and X-ray structure diffraction. Further, the surface of the fine particles is etched stepwise with an acidic solution, an electron beam or the like, and the surface is successively qualitatively quantified to verify that the zinc oxide contains a different element. ESCA or the like is used for such surface analysis.

In the developer of the present invention, the ratio (Z) of the average diameter (Z) of the fine particles to the average diameter (T) of the toner is set in order to achieve a good rise of triboelectrification property even with rapid environmental changes. / T) is preferably 0.5 or less. More preferably, it is 0.3 or less and 0.01 or more.
Here, the average diameter (Z, T) is the average value of 100 particles obtained by directly measuring the particle diameters of the fine particles and the toner with a scanning microscope or the like in the same manner as in the method of measuring the existence ratio of the fine particles. It is a value.

(2) Toner The toner of the present invention preferably has a weight average diameter of 3 μm or more and 10 μm or less. If it is less than 3 μm, the transferability may fluctuate, which may affect the image quality. Also, 10
If it exceeds μm, scattering of toner particles may occur, which is not preferable.

Here, the weight average diameter was measured by the following method.

A Coulter counter TA-II type or a Coulter Multisizer II type (manufactured by Coulter Co.) was used, a device for outputting the number distribution and the volume distribution was connected, and a 1% NaCl aqueous solution was used as an electrolytic solution. As a measuring method, 0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) as a dispersant is added to 100 to 150 ml of the electrolytic aqueous solution, and 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is about 1 to 3 with an ultrasonic disperser.
Dispersion processing is performed for 100 minutes as an aperture.
Using an aperture, the volume and the number were measured, and the volume distribution and the number distribution were calculated. Then, the weight-based weight average diameter (D4) according to the present invention was determined from the volume distribution.

As a channel, 2.00 to 2.52
Less than μm; 2.52 to less than 3.17 μm; 3.17 to
4. 4.0 μm or less; 4.00 to 5.04 μm or less;
04 to less than 6.35 μm; 6.35 to less than 8.00 μm; 8.00 to less than 10.08 μm; 10.08 to 1
Less than 2.70 μm; 12.70 to less than 16.00 μm;
16.00 to less than 20.20 μm; 20.20 to 25.
Less than 40 μm; 25.40 to less than 32.00 μm; 3
Thirteen channels with a size of 2.00 to less than 40.30 μm were used (the median value of the channels is used as a representative value for each channel).

In addition to the fine particles, it is more preferable to externally add an inorganic fine powder to the developer of the present invention. As such an inorganic powder, at least silica, titanium oxide, alumina,
Alternatively, it is preferably selected from the composite oxides thereof, and the average primary particle diameter is preferably 4 nm or more and 80 nm or less. Of these, silica is the most preferable. If it is less than 4 nm, it may be difficult to uniformly disperse it into the toner due to aggregation of the inorganic fine powder, and if it exceeds 80 nm, it may be easily released from the toner and the fluidity may be changed. The primary particle size is determined by scanning electron microscope (SE
It is an average value directly obtained by magnifying photographing such as M).

Further, the developer of the present invention may contain a fluidity improver. The fluidity improver is a fluidity improver that can be added to the toner to increase the fluidity before and after the addition. For example, vinylidene fluoride fine powder, fluororesin powder such as polytetrafluoroethylene fine powder, silica as the above-mentioned inorganic powder, titanium oxide, alumina, silane coupling agent, titanium coupling agent, silicone oil Surface-treated ones are preferable, and silica is particularly preferable.

The preferred silica is a fine powder produced by vapor phase oxidation of a silicon halogen compound and is what is called so-called dry process silica or fumed silica. For example, the thermal decomposition oxidation reaction of silicon tetrachloride gas in oxyhydrogen flame is utilized.

Examples of commercially available silica fine powder produced by vapor phase oxidation of a silicon halogen compound include those commercially available under the following trade names.

[0041]   AEROSIL (Japan Aerosil Co., Ltd.) 130                                                       200                                                       300                                                       380                                                       TT600                                                       MOX170                                                       MOX80                                                       COK84   Ca-O-SiL (CABOT Co.) M-5                                                       MS-7                                                       MS-75                                                       HS-5                                                       EH-5   Wacker HDK N 20 V15     (WACKER-CHEMIE GMBH company) N20E                                                       T30                                                       T40   D-C Fine Silica (Dow Corning Co.)   Francol (Fransil)

A treated silica fine powder obtained by subjecting a silica fine powder produced by vapor-phase oxidation of a silicon halogen compound to a hydrophobic treatment is more preferable. The treated silica fine powder has a hydrophobicity of 30 to 80 measured by a methanol titration test.
Those treated with silica fine powder so as to show a value in the range of are particularly preferable.

As a method of hydrophobizing, it is imparted by chemically treating with an organic silicon compound or the like which reacts with or physically adsorbs on silica fine powder. As a preferred method, silica fine powder produced by vapor phase oxidation of a silicon halogen compound is treated with an organosilicon compound.

Examples of the organosilicon compound include hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, Brommethyldimethylchlorosilane,
α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilylmercaptan, trimethylsilylmercaptan, triorganosilylacrylate, vinyldimethylacetoxysilane, dimethylethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane , Hexamethyldisiloxane, 1,3-divinyltetramethyldisiloxane, 1,3-diphenyltetramethyldisiloxane and 2 to 12 siloxane units per molecule, one for each terminally located unit. Examples include dimethylpolysiloxane containing a hydroxyl group bonded to Si. Further, a silicone oil such as dimethyl silicone oil may be mentioned. These are used alone or as a mixture of two or more. In the present invention, silicone oil treatment is particularly preferable.

The above-mentioned powder has a specific surface area of 30 m ² / g or more, preferably 50, by nitrogen adsorption measured by the BET method.
Those with m ² / g or more give good results.

Further, the external addition amount is 0.01 to 8 parts by mass, preferably 0.1 to 4 parts by mass with respect to 100 parts by mass of the toner.

The toner of the present invention can be manufactured by a pulverization method or a polymerization method.

First, the pulverization method will be exemplified.

Binder resin, magnetic substance, release agent, charge control agent,
In some cases, components necessary as a toner such as a colorant and other additives are sufficiently mixed with a mixer such as a Henschel mixer or a ball mill, and then melt-kneaded using a heat kneader such as a heating roll, a kneader or an extruder. Disperse or dissolve other toner materials such as a magnetic material in resins in which they are mutually compatible, cool and solidify, pulverize, and then classify,
If necessary, surface treatment can be performed to obtain toner particles. Either the classification or the surface treatment may be performed first. In the classification step, it is preferable to use a multi-division classifier in terms of production efficiency. The crushing process can be performed by a method using a known crushing device such as a mechanical impact type and a jet type.

Examples of the binder resin used in the toner of the present invention include homopolymers of styrene such as polystyrene, poly-p-chlorostyrene, polyvinyltoluene and the like, and substitution products thereof; styrene-p-chlorostyrene copolymerization. Copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethacryl copolymer, styrene-acrylonitrile copolymer Polymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer Styrenic copolymers such as polymers Polyvinyl chloride, phenol resin, natural resin modified phenol resin, natural resin modified maleic acid resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester resin, polyurethane, polyamide resin, furan resin, epoxy resin, xylene resin, Examples thereof include polyvinyl butyral, terpene resin, coumarone indene resin, and petroleum-based resin.

A vinyl monomer is used as a comonomer for the styrene monomer of the styrene copolymer. Examples of vinyl monomers include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, methacrylic acid, methyl methacrylate. , Ethyl methacrylate,
A monocarboxylic acid having a double bond such as butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide or a substituted product thereof;
For example, a dicarboxylic acid having a double bond such as maleic acid, butyl maleate, methyl maleate, and dimethyl maleate and its substituted products; for example, vinyl esters such as vinyl chloride, vinyl acetate, vinyl benzoate; for example, vinyl. Examples thereof include vinyl ketones such as methyl ketone and vinyl hexyl ketone; for example, vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether. These are used alone or in combination of two or more. As the cross-linking agent, a compound having two or more polymerizable double bonds is mainly used, and examples thereof include aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; for example, ethylene glycol diacrylate, ethylene glycol dimethacrylate, and the like. A carboxylic acid ester having two double bonds such as 1,3-butanediol dimethacrylate; a divinyl compound such as divinylaniline, divinyl ether, divinyl sulfide, divinyl sulfone; and a compound having three or more vinyl groups; Are used alone or as a mixture.

Further, the binder resin used in the present invention may be a polymer or copolymer crosslinked with a crosslinking monomer. Examples of the aromatic divinyl compound include divinylbenzene and divinylnaphthalene; examples of the diacrylate compounds linked by an alkyl chain include ethylene glycol diacrylate, 1,3-butylene glycol diacrylate and 1,4-butanediol diamine. Acrylate, 1,5-pentanediol diacrylate, 1,6 hexanediol diacrylate, neopentyl glycol diacrylate, and the above compounds in which the acrylate is replaced with methacrylate; linked by an alkyl chain containing an ether bond Examples of diacrylate compounds include diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol # 400 diacrylate. , Polyethylene glycol # 600 diacrylate, dipropylene glycol diacrylate, and those in which the acrylate of the above compounds is replaced with methacrylate; examples of diacrylate compounds linked by a chain containing an aromatic group and an ether bond include , Polyoxyethylene (2)-
2,2-bis (4-hydroxyphenyl) propane diacrylate, polyoxyethylene (4) -2,2-bis (4-hydroxyphenyl) propane diacrylate, and those obtained by replacing the acrylates of the above compounds with methacrylates are mentioned. Examples of the polyester type diacrylates include trade name MANDA (Nippon Kayaku Co., Ltd.).

Here, as a cross-linking agent, pentaerythritol triacrylate, trimethylolethane triacrylate, trimethylolpropane triacrylate,
Tetramethylolmethane tetraacrylate, oligoester acrylates, and compounds obtained by replacing the acrylates of the above compounds with methacrylates; triallyl cyanurate, triallyl trimellitate and the like can be mentioned.

These cross-linking agents are based on other monomer components 10
0 to 10 parts by mass, preferably 0.01 to 10 parts by mass,
More preferably, 0.03 to 5 parts by mass can be used. Among the crosslinkable monomers, those that are preferably used in the resin for toner from the viewpoints of fixing property and anti-offset property include aromatic divinyl compounds (particularly divinylbenzene), di-chains linked by a chain containing an aromatic group and an ether bond. Acrylate compounds may be mentioned.

The binder resin used in the present invention is preferably a vinyl resin, a polyester resin, an epoxy resin or the like, more preferably a vinyl resin and a polyester resin. Further, in the present invention, a vinyl monomer homopolymer or copolymer, polyester, polyurethane, epoxy resin, polyvinyl butyral, rosin,
A modified rosin, a terpene resin, a phenol resin, an aliphatic or alicyclic hydrocarbon resin, an aromatic petroleum resin, or the like can be used by mixing with the binder resin described above, if necessary. When two or more kinds of resins are mixed and used as a binder resin, it is preferable to mix resins having different molecular weights at an appropriate ratio.

As the physical properties of the developer, the glass transition temperature is preferably 45 to 80 ° C., more preferably 50 to 70 ° C., and the number average molecular weight (Mn) is 1,000 to 50,000 and the weight average is in the molecular weight distribution measured by GPC. The molecular weight (Mw) is preferably 6,000 to 1,000,000. The acid value is preferably 90 mgKOH / g or less, more preferably 50 mgKOH / g or less.

The glass transition point (Tg) of the developer was measured under the following conditions using a differential thermal analyzer (DSC measuring device) and DSC-7 (manufactured by Perkin Elmer). Sample: 5 to 20 mg, preferably 10 mg Temperature curve: Temperature increase I (20 ° C. → 180 ° C., temperature increase rate 10 ° C./min.) Temperature decrease I (180 ° C. → 10 ° C., temperature decrease rate 10 ° C./min.) Temperature increase II (10 ° C. → 180 ° C., temperature rising rate 10 ° C./min.) Tg measured in temperature rising II is taken as a measured value. Measurement method: Put the sample in an aluminum pan and use an empty aluminum pan as a reference. The crossing point between the line at the midpoint of the base line before and after the appearance of the endothermic peak and the differential heat curve was defined as the glass transition point Tg.

In the present invention, in the DSC curve measured by a differential scanning calorimeter (DSC) of the toner, the endothermic main peak temperature at the time of heating is preferably 60 to 140 ° C.
Is more preferable in the toner having the above-mentioned specific particle size distribution, and the exothermic main peak temperature at the time of cooling is preferably in the range of 60 to 150 ° C, and more preferably in the range of 60 to 120 ° C. 60-13
The range of 0 ° C. is particularly preferable for the toner having the above-mentioned specific particle size distribution.

For DSC measurement, for example, DSC-7 manufactured by Perkin Elmer can be used. The amount of sample used for measurement is about 10 to 15 mg in the case of a toner sample.
In the case of a wax sample, about 2-5 mg is used.

The measuring method is ASTM D3418-82.
Carry out according to. The DSC curve used in the present invention has a temperature rate of 10 ° C./min after the temperature is raised once and a previous history is taken.
The DSC curve measured when the temperature is lowered or raised in the temperature range of 0 to 200 ° C. is used.

The binder resin made of a vinyl polymer or copolymer can be synthesized, for example, by the following method. As a synthesis method, a bulk polymerization method, a solution polymerization method, a suspension polymerization method, or an emulsion polymerization method can be used.

For example, when a carboxylic acid monomer or an acid anhydride monomer is used, it is preferable to use the bulk polymerization method or the solution polymerization method because of the nature of the monomer. A vinyl copolymer can be obtained by a bulk polymerization method or a solution polymerization method using a monomer such as a dicarboxylic acid, a dicarboxylic acid anhydride, or a dicarboxylic acid monoester. In the solution polymerization method, the dicarboxylic acid and dicarboxylic acid monoester units can be partially dehydrated by devising the distillation conditions when the solvent is distilled off. Further, the vinyl-based copolymer obtained by the bulk polymerization method or the solution polymerization method is subjected to heat treatment, so that it can be further dehydrated. It is also possible to partially esterify the acid anhydride with a compound such as an alcohol.

On the contrary, the thus obtained vinyl-based copolymer can be partially hydrolyzed to form a dicarboxylic acid by ring closure of the acid anhydride group.

On the other hand, by using a dicarboxylic acid monoester monomer, a vinyl copolymer obtained by a suspension polymerization method or an emulsion polymerization method is dehydrated from the anhydride by dehydration by heat treatment and ring opening by hydrolysis treatment. Obtainable. The vinyl copolymer obtained by the bulk polymerization method or the solution polymerization method is dissolved in a monomer, and then by a suspension polymerization method or an emulsion polymerization method, a method of obtaining a vinyl polymer or a copolymer is used, A part of the acid anhydride can be opened to obtain a dicarboxylic acid unit. Another resin may be mixed in the monomer during the polymerization, and the obtained resin can be subjected to an acid anhydride treatment by a heat treatment and an esterification treatment by a ring-opening alcohol treatment of the acid anhydride by a weak alkaline water treatment.

Since the dicarboxylic acid and dicarboxylic acid anhydride monomers have strong alternating polymerizability, the following method is preferable in order to obtain a vinyl-based copolymer in which functional groups such as anhydride and dicarboxylic acid are randomly dispersed. one of. This is a method in which a vinyl-based copolymer is obtained by a solution polymerization method using a dicarboxylic acid monoester monomer, the vinyl-based copolymer is dissolved in the monomer, and a binder resin is obtained by a suspension polymerization method. In this method, all or the dicarboxylic acid monoester portion can be dealcoholized and ring-closed and dehydrated depending on the treatment conditions when the solvent is distilled off after the solution polymerization to obtain an acid anhydride. During suspension polymerization, the acid anhydride group undergoes ring opening by hydrolysis to give a dicarboxylic acid.

In the acid anhydride formation in the polymer, the infrared absorption of carbonyl shifts to a higher wave number side than that of the acid or ester, so that the formation or disappearance of the acid anhydride can be confirmed. In the binder resin thus obtained, the carboxyl group, the anhydride group and the dicarboxylic acid group are uniformly dispersed in the binder resin, so that the toner can be imparted with good chargeability.

The following polyester resins are also preferable as the binder resin. Polyester resin is 45 ~ in all components
55 mol% is alcohol component, 55-45 mo
1% is the acid component. Alcohol components include ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexane. Examples thereof include diols, neopentyl glycol, 2-ethyl 1,3-hexanediol, hydrogenated bisphenol A, bisphenol derivatives, diols, and polyhydric alcohols such as glycerin, sorbit and sorbitan.

Examples of the divalent carboxylic acid containing 50 mol% or more in the total acid components include benzenedicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid and phthalic anhydride or their anhydrides; succinic acid, adipic acid, sebacic acid, Alkyl dicarboxylic acids such as azelaic acid or their anhydrides, and succinic acid substituted with an alkyl group or an alkenyl group having 6 to 18 carbon atoms or their anhydrides; fumaric acid, maleic acid, citraconic acid, itaconic acid Saturated dicarboxylic acid or its anhydride, and the like,
Examples of the trivalent or higher carboxylic acid include trimellitic acid, pyromellitic acid, benzophenonetetracarboxylic acid and anhydrides thereof.

The alcohol component of the particularly preferred polyester resin is a bisphenol derivative, and the acid component is phthalic acid, terephthalic acid, isophthalic acid or its anhydride, succinic acid, n-dodecenylsuccinic acid or its anhydride, fumaric acid, And dicarboxylic acids such as maleic acid and maleic anhydride; and trimellitic acid or its tricarboxylic acid anhydride.

This is because the toner using the polyester resin obtained from the acid component and the alcohol component as a binder resin has good fixability and excellent offset resistance.

In the toner of the present invention, it is preferable to use a charge control agent by blending (internally adding) the toner particles. The charge control agent makes it possible to control the optimum charge amount according to the developing system, and particularly, in the present invention, it is possible to further stabilize the balance between the particle size distribution and the charge, and the charge control agent is used. As a result, it is possible to further clarify the function separation and the mutual complementarity for improving the image quality by the particle size range described above.

Examples of the positive charge control agent include modified products of nigrosine and fatty acid metal salts; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate and tetrabutylammonium tetrafluoroborate. They can be used alone or in combination of two or more. Among these,
Charge control agents such as nigrosine compounds and quaternary ammonium salts are particularly preferably used. Further, a monomer homopolymer or a copolymer with a polymerizable monomer such as styrene, acrylic acid ester and methacrylic acid ester as described above can be used as a positive charge control agent. The charge control agent also has a function as (all or part of) a binder resin.

As the negative charge control agent, for example, organometallic complexes and chelate compounds are effective, and there are monoazo metal complexes, acetylacetone metal complexes, aromatic hydroxycarboxylic acids, and aromatic dicarboxylic acid type metal complexes.
Other examples include aromatic hydroxycarboxylic acids, aromatic mono- and polycarboxylic acids, metal salts, anhydrides, esters, and phenol derivatives such as bisphenol.

The above-mentioned charge control agent (which does not act as a binder resin) is preferably used in the form of fine particles. In this case, the number average particle size of this charge control agent is
Specifically, it is preferably 4 μm or less (further, 3 μm or less). When internally added to the toner, such a charge control agent is used in an amount of 0.1 to 20 parts by mass (preferably 0.2 to 10 parts by mass) with respect to 100 parts by mass of the binder resin.

The toner of the present invention may be a magnetic toner.

As the magnetic material contained in the magnetic toner,
Iron oxides such as magnetite, maghemite, ferrite and other metal oxides; Fe, Co, N
metals such as i, or these metals and Al, C
o, Cu, Pb, Mg, Ni, Sn, Zn, Sb, B
Examples thereof include alloys with metals such as e, Bi, Cd, Ca, Mn, Se, Ti, W and V, and mixtures thereof.

Specifically, as the magnetic material, tetra-trioxide is used.
Iron (Fe₃O_Four), Ferric oxide (γ-Fe)₂O₃),iron oxide
Zinc (ZnFe₂O_Four), Yttrium iron oxide (Y₃Fe_Five
O₁₂), Cadmium iron oxide (CdFe₂O_Four), Iron oxide
Dolinium (Gd₃Fe_FiveO₁₂), Iron oxide copper (CuFe₂
O_Four), Iron oxide lead (PbFe)₁₂O₁₉), Iron oxide nickel
(NiFe₂O_Four), Iron neodymium oxide (NdFe₂O₃),
Barium iron oxide (BaFe₁₂O₁₉), Iron oxide magnesium
Mu (MgFe₂O_Four), Iron manganese oxide (MnFe
₂O_Four), Lanthanum iron oxide (LaFeO₃), Iron powder (F
e), cobalt powder (Co) and nickel powder (Ni)
You can The above magnetic materials may be used alone or in combination of two or more.
Used in combination. A particularly suitable magnetic material is ferrosoferric oxide.
Alternatively, it is a fine powder of γ-iron sesquioxide. Content of magnetic material
Is a magnetic substance 10 to 20 parts by weight with respect to 100 parts by weight of the binder resin.
0 parts by mass, preferably 20 to 150 parts by mass
Yes.

As the colorant used in the toner, conventionally known dyes and / or pigments can be used. Examples of the colorant include carbon black, phthalocyanine blue, peacock blue, permanent red, lake red, rhodamine lake, hunter yellow, permanent yellow, and benzidine yellow. The content of the colorant is 0.1 to 20 parts by mass, and preferably 0.5 to 100 parts by mass of the binder resin.
20 parts by mass, preferably 12 parts by mass or less, and more preferably 0.5 to 9 parts by mass in order to improve the transparency of the OHP film on which the toner image is fixed.

A release agent is preferably contained in the toner particles if necessary.

Examples of the release agent include the following. Low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax, aliphatic hydrocarbon wax such as paraffin wax, oxide of aliphatic hydrocarbon wax such as oxidized polyethylene wax, or block copolymers thereof; carnauba wax, Waxes containing a fatty acid ester as a main component such as sazol wax and montanic acid ester wax; and those obtained by partially or completely deoxidizing fatty acid ester such as deoxidized carnauba wax. Further, saturated straight chain fatty acids such as palmitic acid, stearic acid, and montanic acid; unsaturated fatty acids such as brassic acid, eleostearic acid, and valinaric acid; stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnaubayl alcohol, ceryl alcohol. Saturated alcohols such as melicyl alcohol; long-chain alkyl alcohols; polyhydric alcohols such as sorbitol; fatty acid amides such as linoleic acid amide, oleic acid amide, and lauric acid amide;
Saturated fatty acid bisamides such as methylenebisstearic acid amide, ethylenebiscapric acid amide, ethylenebislauric acid amide, hexamethylenebisstearic acid amide; ethylenebisoleic acid amide, hexamethylenebisoleic acid amide, N, N'-dio Unsaturated fatty acid amides such as rail adipic amide and N, N-dioleyl sebacic acid amide; aromatic bisamides such as m-xylene bisstearic acid amide and N, N-distearyl isophthalic acid amide; calcium stearate
Fatty acid metal salts such as calcium laurate, zinc stearate and magnesium stearate (generally referred to as metallic soap), waxes obtained by grafting aliphatic hydrocarbon waxes with vinyl monomers such as styrene and acrylic acid. Kinds; partial esterification products of fatty acids and polyhydric alcohols such as behenic acid monoglyceride, and methyl ester compounds having a hydroxyl group obtained by hydrogenation of vegetable oils and fats. The release agent is 0.1 to 20 parts by mass per 100 parts by mass of the binder resin,
It is preferably 0.5 to 10 parts by mass.

In the DSC curve of the wax contained in the toner measured by a differential scanning calorimeter (DSC),
The endothermic main peak temperature during temperature rise is preferably 60 to 14
It is particularly preferable for the toner having the above-mentioned specific particle size distribution to be in the range of 0 ° C., more preferably in the range of 60 to 120 ° C., and the exothermic main peak temperature at the time of cooling is preferably in the range of 60 to 150 ° C. Preferably 60-
The range of 130 is particularly preferable for the toner having the above-mentioned specific particle size distribution.

Next, suspension polymerization will be exemplified as a polymerization method.

A polymerizable monomer and a colorant, and if necessary, a polymerization initiator, a cross-linking agent, a charge control agent, a release agent, a plasticizer, a magnetic material, and other additives are added to a homogenizer, a ball mill, a colloid mill. The monomer system uniformly dissolved or dispersed by a disperser such as an ultrasonic disperser is suspended in an aqueous medium containing a dispersion stabilizer. The polymerization initiator is
When other additives are added to the polymerizable monomer, they may be added at the same time, or may be mixed immediately before being suspended in the aqueous medium. Also, a polymerization initiator dissolved in a polymerizable monomer or a solvent may be added immediately after granulation and before starting the polymerization reaction.

The polymerization temperature is 40 ° C. or higher, generally 50 to 9
Polymerization is carried out by setting the temperature at 0 ° C. When the polymerization is carried out within this temperature range, the release agent and waxes to be sealed inside are precipitated by phase separation and the encapsulation becomes more complete. At the end of the polymerization reaction, it is possible to raise the reaction temperature to 90 to 150 ° C. in order to consume the remaining polymerizable monomer.

Examples of the polymerizable monomer constituting the polymerizable monomer system include the following.

Examples of the polymerizable monomer include styrene-based monomers such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-ethylstyrene, methyl acrylate, and acrylic acid. Ethyl acetate, n-butyl acrylate, isobutyl acrylate, n-propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, etc. Acrylic esters, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate,
Examples thereof include methacrylic acid esters such as 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, and other monomers such as acrylonitrile, methacrylonitrile, and acrylamide.

These monomers may be used alone or in combination. Among the above-mentioned monomers, it is preferable to use styrene or a styrene derivative alone or in combination with other monomers, from the viewpoint of developing characteristics and durability of the toner.

A resin may be added to the monomer system for polymerization.

For example, since the monomer is water-soluble, it dissolves in an aqueous suspension to cause emulsion polymerization and thus cannot be used. Amino group, carboxylic acid group, hydroxyl group, sulfonic acid group, glycidyl group, nitrile group, etc. When it is desired to introduce a functional group-containing monomer component into the toner, a copolymer such as a random copolymer, a block copolymer, or a graft copolymer of these and a vinyl compound such as styrene or ethylene is prepared. Alternatively, it can be used in the form of a polycondensate of polyester, polyamide, etc., or a polyaddition polymer such as polyether, polyimine etc. When such a high molecular weight polymer containing a polar functional group is coexisted in the toner, the wax component is phase-separated, the inclusion becomes stronger, and the toner having good offset resistance, blocking resistance, and low temperature fixing property is obtained. Obtainable. When such a polymer having a polar functional group is used, its average molecular weight is preferably 5,000 or more. 5,000 or less, especially 4,0
When the ratio is 00 or less, the present polymer is likely to concentrate near the surface, which is not preferable because the developability and blocking resistance are likely to be adversely affected. As the polar polymer, polyester resin is particularly preferable.

Further, a resin other than the above may be added to the monomer system for the purpose of improving the dispersibility and fixing property of the material, the image characteristics, etc. Examples of the resin used include polystyrene and polyvinyltoluene. Homopolymers of styrene and its substitutes; styrene-propylene copolymers, styrene-vinyltoluene copolymers, styrene-
Vinyl naphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-dimethylaminoethyl acrylate copolymer Polymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-dimethylaminoethyl methacrylate copolymer, styrene-vinyl methyl ether copolymer Polymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer Styrene-based copolymers such as coalesce; Methyl methacrylate, polybutyl methacrylate, polyvinyl acetate, polyethylene, polypropylene, polyvinyl butyral, silicone resin, polyester resin, polyamide resin, epoxy resin, polyacrylic acid resin, rosin, modified rosin, terpene resin, phenol resin, aliphatic or fat Aromatic hydrocarbon resins and aromatic petroleum resins can be used alone or in combination. The addition amount of these resins is preferably 1 to 20 parts by mass with respect to 100 parts by mass of the monomer. If it is less than 1 part by mass, the effect of addition is small, while if it is added in an amount of 20 parts by mass or more, it becomes difficult to design various physical properties of the polymer toner.

As the polymerization initiator, 2,2'-azobis- (2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1,1'-azobis (cyclohexane-1-carbonitrile) is used. Nitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile,
Azo- or diazo-type polymerization initiators such as azobisisobutyronitrile; benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, t- Examples thereof include peroxide-based polymerization initiators such as butyl peroxy 2-ethylhexanoate.

A crosslinking agent may be added, and the preferable addition amount is 0.001 to 15% by mass. As the cross-linking agent, a compound having two or more polymerizable double bonds is mainly used, and examples thereof include aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene and the like; for example, ethylene glycol diacrylate, ethylene glycol dimethacrylate, Carboxylic acid ester having two double bonds such as 1,3-butanediol dimethacrylate; Divinyl compound such as divinylaniline, divinyl ether, divinyl sulfide, divinyl sulfone;
And a compound having three or more vinyl groups; used alone or as a mixture.

As the dispersion stabilizer, a surfactant or organic
Inorganic dispersants can be used, and among them, inorganic dispersants are preferred from the viewpoint of dispersion stability. Examples of the inorganic dispersant include calcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, and other polyvalent metal salts of phosphate, calcium carbonate, carbonates such as magnesium carbonate, inorganic salts such as calcium metasilicate, calcium sulfate, and barium sulfate. Examples thereof include inorganic oxides such as calcium hydroxide, magnesium hydroxide, aluminum hydroxide, silica, bentonite, and alumina. The inorganic dispersant is 0.2 to 20 with respect to 100 parts by mass of the polymerizable monomer.
Although it is desirable to use a mass part alone, it is difficult to generate ultrafine particles, but it is rather difficult to atomize the toner, so 0.001 to 0.1 part by mass of a surfactant may be used together. Examples of the surfactant include sodium dodecylbenzene sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, sodium stearate, potassium stearate and the like.

As the charge control agent, as a negative charge control agent, a metal compound of an aromatic carboxylic acid such as salicylic acid, alkylsalicylic acid, dialkylsalicylic acid, naphthoic acid or dicarboxylic acid, a metal salt or a metal complex of an azo dye or azo pigment is used. , Polymer compounds having a sulfonic acid or carboxylic acid group in the side chain, boron compounds, urea compounds, silicon compounds, calixarene and the like. Examples of the positive charge control agent include a quaternary ammonium salt, a polymer type compound having the quaternary ammonium salt in the side chain, a guanidine compound, a nigrosine compound, an imidazole compound, and the like. As a method of incorporating the charge control agent into the toner, there are a method of adding it inside the toner mother particles and a method of adding it externally. The amount of these charge control agents used is determined according to the type of binder resin, the presence or absence of other additives, and the toner manufacturing method including the dispersion method, and is not uniquely limited. It is preferably used in an amount of 0.1 to 10 parts by mass, more preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the binder resin. It should be noted that the addition of the charge control agent is not essential, and the toner does not necessarily need to contain the charge control agent by positively utilizing the triboelectric charging between the toner layer thickness regulating member and the toner carrier.

Examples of the releasing agent include petroleum waxes such as paraffin wax, microcrystalline wax, petrolactam and their derivatives, montan wax and its derivatives, hydrocarbon wax and its derivatives by the Fischer-Tropsch method, and polyolefin wax represented by polyethylene. And natural waxes such as carnauba wax and candelilla wax and their derivatives. The derivatives include oxides, block copolymers with vinyl monomers, and graft modified products. Furthermore, fatty acids such as higher aliphatic alcohols, stearic acid, palmitic acid, or their compounds, acid amide wax, ester wax, ketone, hydrogenated castor oil and its derivatives, plant wax, animal wax, etc. Peaks above 45 ° C and below 110 ° C, and above 50 ° C and above 9
Those having a temperature of 0 ° C. or lower are preferable. The content of the release agent is preferably in the range of 0.5 to 50 mass% with respect to the entire toner. If the content is less than 0.5% by mass, the low-temperature offset suppressing effect is poor, and if it exceeds 50% by mass, the long-term storability may deteriorate.

[0096]

EXAMPLES The effects of the present invention will be described below with reference to examples. The present invention is not limited to these examples.

(1) Production Example of Fine Particles [Production Example of Fine Particles 1] Al / Zn (molar ratio) = 0.07
An aqueous solution of aluminum sulfate was added to the aqueous dispersion of zinc oxide at a ratio of 1, and an aqueous solution of ammonium carbonate was further added and sufficiently stirred to prepare a uniform slurry. Spherical silica was added to this slurry as base particles, and the mixture was heated at 60 ° C. for 1 hour. The slurry is filtered, washed with water, dried, and then calcined, and then a reduction firing furnace (750
Baking for 1 hour.

The calcined material was crushed and then classified, and the mass ratio of Zn element to silica particles (Zn / matrix particle) was 0.21, volume average diameter 1.0 μm, 5% or more were 0% by number, primary particles were Diameter 0.5 μm, volume resistance 7 × 10 ⁵ Ωcm
Of white powder was obtained. This is designated as zinc oxide fine particle 1.
Here, the primary particle diameter is an average diameter calculated from direct observation by SEM, like the average diameter (Z) of fine particles.

[Production Example of Fine Particles 2] Water was added to zinc oxide and sufficiently stirred, then titanium oxide particles were added, and KOH was further added.
And heated. Aluminum chloride was dissolved in this slurry at a ratio of Al / Zn (molar ratio) = 0.10 K
Aqueous OH solution was added and heated at 70 ° C. for 1 hour. After heating
The slurry was filtered, washed with water, sufficiently dried, and then fired in a hydrogen atmosphere reducing firing furnace (700 ° C.) for 1 hour.

The fired body was crushed and then classified to obtain Zn.
/ Major particles are 0.17, volume average diameter 1.8μm, 5μm
The above is 0% by number, primary particle size is 1.5 μm, volume resistance is 1 ×
10 ⁶A white powder of Ωcm was obtained. Let this be fine particle 2.
It

[Production Example of Fine Particles 3] A spherical silica was impregnated with an aqueous solution of zinc sulfate and aluminum sulfate mixed at a ratio of Al / Zn (molar ratio) = 0.15 and dried at 120 ° C. This was dispersed in a sodium hydroxide solution and heated at 60 ° C. for 1 hour.

After that, it was filtered, washed with water, dried, and then fired in a reduction firing furnace (600 ° C.) in a hydrogen atmosphere for 1 hour. The fired body is crushed and then classified, and Zn / matrix particles have a particle size of 0.29, a volume average diameter of 0.5 μm, 5% or more of 0% by number, a primary particle diameter of 0.3 μm, and a volume resistance of 7 × 10 ⁴ Ωcm
Of white powder was obtained. This is referred to as fine particle 3.

(2) Toner [Production Example of Toner Classification Product 1] Polyester resin (Tg6
0 ° C, molecular weight: Mp6900, Mn3050, Mw54
500) 100 parts by mass, monoazo metal complex (negative charge control agent) 3.0 parts by mass, low molecular weight ethylene-propylene copolymer (endothermic main peak temperature: 86 ° C, exothermic main peak temperature: 86.5 ° C) 3. After mixing 5 parts by mass with a Henschel mixer, they were kneaded with a biaxial kneader set to a temperature of 130 ° C. The kneaded product was cooled, roughly crushed with a hammer mill, and then crushed with a mechanical crusher (turbo mill). Further, classification was carried out by an airflow classifier to obtain a non-magnetic toner classified product 1 having a weight average particle diameter of 7.5 μm.

As a two-component developing carrier, 45 μm
A developing carrier 1 was prepared by coating 0.7 parts by mass of an acrylic resin on 100 parts by mass of a ferrite carrier of m.

[Production Example of toner classified product 2] 100 parts by mass of styrene-butyl acrylate-butyl maleate half ester copolymer (Tg 62 ° C, molecular weight: Mp1050)
0, Mn6000, Mw225000), magnetic iron oxide 9
5 parts by mass (0.18 μm, σs83.1 Am ² / kg,
σr11.4 Am ² / kg), monoazo metal complex 2.5
2 parts by mass of low molecular weight ethylene-propylene copolymer (endothermic main peak temperature: 85 ° C, exothermic main peak temperature: 86.5 ° C) were mixed with a Henschel mixer, and then the biaxial kneading was performed at a temperature of 130 ° C. Kneaded in a machine.
The kneaded product was cooled, roughly crushed with a hammer mill, and then crushed with a mechanical crusher (turbo mill). Further, classification was performed by an airflow classifier to obtain a magnetic toner classified product 2 having a weight average particle diameter of 7.0 μm.

Example 1 (1) Production of Toner 1 Fine particles 1 (0.7 parts by mass) were added to toner classified product 1 (100 parts by mass), and further treated with dimethyl silicone oil, a fine powder of hydrophobic silica. (1.2 parts by mass) was added and externally added with a Henschel mixer. The ratio of fine particles existing on the surface of the toner was 4.0, and Z / T was 0.09. This external additive was mixed with 7 parts by mass of the developing carrier 1 (100 parts by mass) to obtain a developer 1.

(2) Evaluation Method The developing section of a digital copying machine (GP405, manufactured by Canon Inc.) using a laser beam as an image forming apparatus was modified and used for this study. As the developing device, a one-component jumping developing device was modified for two-component development, and as a developing sleeve, a SUS sleeve was blasted with glass beads so that the surface roughness Ra was 1.0. 1kVp for the developing sleeve
AC of p, 2 kHz is superimposed, and the rotation of the photoconductor is 150
Adjusted to the peripheral speed difference of%.

Print ratio 6% under 23 ° C / 60% environment
Using the test chart of No. 1, 1000 images were continuously printed on A4 sheets, and image fog and fine line reproducibility were evaluated as image quality evaluation. In the image fogging evaluation, the scattering state of fine particles was also evaluated.

The image fog is a reflection measuring machine R for fog measurement.
The reflectance of the image white background portion and the unused paper was measured by EFLECTMETER (Tokyo Denshoku Co., Ltd.), and the difference (reflectance of the unused paper-reflectance of the image white background portion) was taken as the fog [%].

Image fogging evaluation is performed according to the following classification.
Less than 1.5% (△) is set as a practical level. ⊚: Less than 0.5% fog ○: 0.5 to 1.0% fog △: 1.0 to 2.0% fog ×: 2.0% or more fog

Next, the evaluation of fine line reproducibility is made up to Δ as a practical level according to the following classification. ○: Good reproducibility △: Minor thin lines or overlaps in some areas ×: Frequent thin lines and overlaps

(3) Evaluation Results Image fog was less than 0.5% (⊚), image deterioration due to release of fine particles did not occur, and fine lines also showed good reproducibility (∘). Further, fusion of the toner to the photoconductor did not occur, and the high image quality was maintained as a whole.

<Example 2> Fine particles 1 (2.0 parts by mass) were added to toner classified product 2 (100 parts by mass), and further treated with dimethyl silicone oil to obtain a fine silica powder (1.0 parts by mass). Was added and externally added with a Henschel mixer to obtain a developer 2. The ratio of fine particles existing on the surface of the toner was 8.5, and Z / T was 0.12.

The developer 2 was placed in a one-component jumping developing device, and the same image evaluation as in Example 1 was performed. Here, in the one-component jumping developing device, a SUS sleeve was blasted with glass beads so that Ra was 0.6. Further, the peripheral speed of the sleeve was adjusted to a peripheral speed difference of 150%.

As a result, image fog ⊚, image deterioration due to release of fine particles did not occur, fine line reproducibility ◯, and fusion did not occur, and high image quality was maintained as a whole.

<Example 3> Hydrophobic silica fine powder (1.2 parts by mass) obtained by adding fine particles 2 (1.0 part by mass) to toner classified product 1 (100 parts by mass) and further treating with dimethyl silicone oil. Was added and externally added with a Henschel mixer. The ratio of fine particles existing on the surface of the toner is 5.6,
Z / T was 0.24. 7 parts by mass of this external additive is mixed with 1 part of the developing carrier (100 parts by mass) to prepare a developer 3
Got

Image evaluation was carried out in the same manner as in Example 1 by using this developer 3, image fog ⊚, image deterioration due to release of fine particles did not occur, fine line reproducibility ◯, and fusion did not occur. Therefore, the same high image quality as in Example 1 was obtained.

<Example 4> Fine particles 3 (1.2 parts by mass) were added to the toner classified product 1 (100 parts by mass), and the particles were further treated with dimethyl silicone oil to obtain a fine hydrophobic silica powder (1.2 parts by mass). Was added and externally added with a Henschel mixer. The ratio of the fine particles present on the surface of the toner is 13.
5, Z / T was 0.05. This external additive was mixed with 7 parts by mass of the developing carrier 1 (100 parts by mass) to obtain a developer 4.

Image evaluation was carried out in the same manner as in Example 1 using this developer 4. Image fog ⊚, image deterioration due to release of fine particles did not occur, fine line reproducibility ◯, and fusion did not occur. Therefore, the same high image quality as in Example 1 was obtained.

<Example 5> When the evaluation of Example 1 was performed in a low humidity environment (15 ° C / 5%), the image fog was ⊚ and the fine line reproducibility was ∘, which was caused by triboelectrification charge-up. No image defect was observed, and the same image quality as in Example 1 was obtained.

Example 6 The evaluation of Example 1 was performed in a high humidity environment (30 ° C./80%). As a result, the image fog was ⊚ and the fine line reproducibility was ∘ in both the initial image and the image after the durability test. From the initial stage, the same image quality as in Example 1 was obtained.

<Example 7> In Example 4, a developer 5 in which the ratio of the fine particles present on the surface of the toner was reduced to 0.2 was prepared, and the same evaluation was carried out.
Image fog of more than 5% was confirmed (◯), and fine line reproducibility was partially thinned (Δ), but the image quality was at a practical level.

Comparative Example 1 Fine particles 2 were produced without adding an aluminum compound to obtain fine particles 4 having a volume average diameter of 1.7 μm, 5 μm or more and 0% by number.
Volume resistance is 1 x 1 at room temperature and normal humidity (23 ° C / 60%).
0 ⁷ Ωcm, 1 × 10 ¹⁰ Ω at low humidity (15 ° C / 5%)
It was cm.

Fine particles 4 (0.8 parts by mass) were added to the toner classified product 1 (100 parts by mass), and further hydrophobic silica fine powder (1.2 parts by mass) was added and externally added by a Henschel mixer. The ratio of fine particles existing on the surface of the toner is 5.8,
Z / T was 0.10. This external additive was mixed with 7 parts by mass of the developing carrier 1 (100 parts by mass) to prepare a developer 6
Got

When this developer 6 was used and the same image evaluation as in Example 1 was carried out, the toner aggregated and image fog (x) frequently occurred, resulting in a marked deterioration of image quality.

<Comparative Example 2> In the production of the fine particles 1, the particle diameter of the spherical silica and the conditions for crushing and classification after sintering are adjusted so that the volume average diameter is 2.5 μm, 5% or more is 9% by number.
Fine particles 5 of

Fine particles 5 (2.5 parts by mass) were added to toner classified product 2 (100 parts by mass), and further hydrophobic silica fine powder (1.2 parts by mass) was added and externally added with a Henschel mixer. Developer 7 is obtained.

When this developer 7 was used and evaluated in the same manner as in Example 2, toner agglomerates were partially generated, and image fog was Δ, but a decrease in fine line reproducibility (×) was conspicuous.
There was unevenness in the density.

Comparative Example 3 In the production of fine particles 1, fine particles 6 having a volume average diameter of 5.7 μm were obtained by adjusting the particle size of the spherical silica and the conditions for crushing and classification after sintering.

Next, in the production of the toner classified product 2, the conditions of pulverization and classification were adjusted to obtain a toner classified product of 10 μm.
To this classified product (100 parts by mass), fine particles 6 (4.5 parts by mass) are added, and further, hydrophobic silica fine powder (1.0 parts by mass) is added and externally added with a Henschel mixer to obtain a developer 8.
Got

When this developer 8 was used and evaluated in the same manner as in Example 2, scattering of fine particles was conspicuous, and image fog (x) and fine line reproducibility (x) were significantly reduced.

[0132]

The developer of the present invention can prevent image fog and reproducibility of fine lines due to uniform triboelectric charging property, and prevent fusion of the toner to the photoconductor to obtain high image quality.
Further, due to the good rise of the triboelectric chargeability, similar high image quality is achieved even after the developer is left standing.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kenji Okado             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation F term (reference) 2H005 AA08 CB07 CB10 CB13 EA05                       EA07

Claims (7)

[Claims] 1. A developer containing at least toner and fine particles carrying zinc oxide containing a different element on the surface of base particles, wherein the toner has at least a binder resin and a colorant, and the fine particles are A mass ratio of Zn element in zinc oxide to the base particles (Zn / base particles) is 0.01 or more and 2 or less, and a molar ratio of a different element to a zinc element (a different element / Zn). Is 0.001 or more and 0.3 or less, the volume average diameter is 0.1 μm or more and less than 5 μm, the number of particles having a particle size of 5 μm or more is less than 3% by number, and the resistance is 1 × 10 ⁹ Ωcm or less. A developer characterized by being present. 2. The different element is aluminum, gallium,
The developer according to claim 1, which is an element selected from the group consisting of indium, tin, and germanium. 3. The developer according to claim 1, wherein the base particles are inorganic particles. 4. The developer according to claim 1, wherein the weight average particle diameter of the toner is 3 to 10 μm. 5. The developer according to claim 1, wherein the fine particles existing on the surface of the toner are 0.3 or more per one toner. 6. The developer according to claim 1, wherein the ratio (Z / T) of the average diameter Z of the fine particles to the average diameter T of the toner is 0.5 or less. 7. The toner contains at least an inorganic fine powder selected from silica, titanium oxide, alumina, or a composite oxide thereof, and having an average primary particle diameter of 4 to 80 nm. Item 7. The developer according to any one of items 1 to 6.