JPH0962029A - Toner for developing electrostatic charge image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a toner having satisfactorily blow property, not causing scattering and capable of forming sharp letters. SOLUTION: The particle size distribution of this toner with at least toner particles and inorg. fine powder satisfies the conditions of -5X+35<=Y<=25X+180 and 3.5<=X<=6.5 when the wt. average diameter (D4 ) is represented by X(μm) and the number % of particles of <=3.17μm on number basis obtd. from the number distribution is represented by Y(%). The inorg. fine powder has been treated with a silane coupling agent and has 60-180g/l bulk density and pH4.5-8.5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic charge image developing toner used in electrophotography, electrostatic recording and the like.

[0002]

2. Description of the Related Art Conventionally, many electrophotographic methods are known. Generally, a photoconductive substance is used to form an electrical latent image on an image bearing member (photoreceptor) by various means, and then the latent image is developed with toner to form a visible image, and if necessary, After the toner image is transferred onto a transfer material such as paper, the toner image is fixed on the transfer material by heat, pressure or the like to obtain a copy.

In recent years, in addition to conventional copying machines, there have been many printers, facsimile machines, and the like using electrophotographic methods.

For example, as a printer device, an LED or LBP printer has recently become the mainstream of the market, and as a technology direction, higher resolution, that is, conventional 240, 300 printers.
What was previously dpi is now 400, 600, and 800 dpi. Accordingly, higher definition has been required for the developing system. In addition, the functions of the copying machine have been advanced, and the digital copying machine is moving toward digitalization. In this direction, a method of forming an electrostatic charge image with a laser is mainly used, so that the direction is also moving toward a higher resolution, and a high-resolution and high-definition developing method is required similarly to a printer. . For this reason, the particle size of the toner is being reduced, and JP-A-1-112253, JP-A-1-191156, JP-A-2-214156, JP-A-2-284158, and JP-A-3-18 are in progress.
1952, JP-A-4-162048, and the like propose a toner having a specific particle size distribution and a small particle size.

However, when a printed matter is obtained by using these toners, especially when printing characters of about 2 mm square or less, when magnified and observed with a microscope or the like, as shown in FIG. There are many toner particles scattered around,
I am still not satisfied with the sharpness of character lines.

Regarding the sharpness of characters, if the weight average diameter of the toner is reduced to 6.0 μm or less, the sharpness of the characters is slightly improved, but the fluidity of the toner is remarkably lowered, and particularly in the case of a solid black image. The decrease in concentration becomes apparent. Further, as the diameter becomes smaller, the fogging phenomenon occurs due to the development of the toner on the non-image area.

Further, as one means for ensuring the fluidity of the toner, JP-A-5-66608 and JP-A-4-986.
No. 0, etc., or an inorganic fine powder that has been subjected to a hydrophobic treatment or an inorganic fine powder that has been subjected to a hydrophobic treatment and then further treated with silicone oil, or the like, or JP-A-61-249059 and JP-A-4-264453. , JP-A-5-34
Japanese Patent No. 6682 discloses a method in which a hydrophobized inorganic fine powder and a silicone oil treated inorganic fine powder are used in combination.

However, when the conventionally known inorganic fine powder is added to the small-diameter toner particles, the toner particles should have good fluidity, and the balance between the character sharpness, solid black density, and hollow character should be maintained. Was in a difficult situation.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a toner for developing an electrostatic charge image, which has good fluidity and is capable of forming sharp characters without scattering.

Another object of the present invention is to provide a toner for developing an electrostatic charge image, which has sharpness and forms a character with no voids in the character.

Another object of the present invention is to provide a toner for developing an electrostatic charge image which forms sharp characters and forms an image having a good solid black density.

Another object of the present invention is to provide a toner for developing an electrostatic charge image which forms an image in which sharp characters are formed and fog is suppressed.

[0013]

The present invention achieves the above object by the following constitution.

That is, according to the present invention, in an electrostatic charge image developing toner having at least toner particles and an inorganic fine powder, the particle size distribution of the electrostatic charge image developing toner has a weight average diameter (D ₄ ) of X (μm). When Y (%) is the number% of 3.17 μm or less on the number basis calculated from the number distribution, the following condition −5X + 35 ≦ Y ≦ −25X + 180 3.5 ≦ X ≦ 6.5 is satisfied, and the inorganic fine powder Is treated with a silane coupling agent,
Bulk density of 60-180 g / liter and pH of 4.5-
It relates to a toner for developing an electrostatic charge image characterized by having a value of 8.5.

Regarding the particle size distribution, Y> -25X + 18
In the case of 0, the fog phenomenon increases, which is not preferable. Y <-
In the case of 5X + 35, the sharpness of the character outline is inferior, which is not preferable. When D ₄ <3.5, the image density is remarkably reduced, which is not preferable. When D ₄ > 6.5, the sharpness of the character outline becomes unsatisfactory. Therefore, having a particle size distribution as in the present invention is necessary to achieve the present invention.

Further, with respect to the toner for developing an electrostatic charge image having such a particle size distribution, it is an inorganic fine powder subjected to silane coupling treatment and has a bulk density of 60 to 180 g / liter, p.
It is necessary that H having a value of 4.5 to 8.5 be added. When the inorganic fine powder is added to the toner particles, the bulk density of the toner particles itself tends to decrease due to the reduction in diameter.Therefore, when mixing with Henschel or the like, there is concern that the dispersibility of the toner particles and the inorganic fine powder particles may deteriorate. To be done. In fact, in the case of the inorganic fine powder having a bulk density smaller than 60 g / liter, which has been used conventionally, scattering and image density reduction considered to be caused by this tendency are observed. 180 g
When the bulk density is higher than 1 liter / liter, the cohesive force of the primary particles of the inorganic fine powder is high, and therefore, when the particles are mixed and dispersed with the toner particles, they are in the state of secondary particles between the toner particles or on the surface of the toner particles. There is concern about the poor distribution that exists. As a matter of fact, the fluidity of the toner is lowered, and the solid black density tends to be low. More preferably used is 65 to 160 g / liter.

Further, as the diameter becomes smaller, it becomes more difficult to control the charging of the toner particles than ever before. When the pH value of the inorganic fine powder added at this time is in the neutral range, the sharpness of characters, the image density, and the voids in the characters tend to be good. That is, the toner particles are generally designed to have a negative or positive unidirectional charging property with a charge control agent or a binder resin. The mechanism of adding an inorganic fine powder that imparts an electric charge that increases or decreases the charging ability of the toner with respect to this charging direction is not clear, but especially small-sized toner particles used in the present invention. Is likely to cause harmful effects. For example, in the case of negatively charged toner,
If the pH is less than 4.5, the splattering will worsen,
If it is larger than 8.5, the solid black density tends to be low and the blank areas in the characters tend to be worse. The more preferable range is 5.
It is 0 to 8.0.

The particle size distribution of the toner for developing an electrostatic image of the present invention is measured by using Coulter counter TA-II or Coulter Multisizer (manufactured by Coulter Co.), and the electrolyte is a 1% NaCl aqueous solution using primary sodium chloride. To prepare. For example, ISOTON R-II (manufactured by Coulter Scientific Japan) can be used. As a measuring method, 100 to 150 m of the electrolytic aqueous solution is used.
A surfactant, preferably 0.1 to 5 ml of alkylbenzene sulfonate is added as a dispersant to 1 l, and 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the volume and the number of toner particles having a size of 2 μm or more are measured by using a 100 μm aperture as an aperture with the above-described measuring device. And the distribution was calculated. Then, the weight-based weight average particle diameter (D ₄ : obtained from the volume distribution according to the present invention):
(The median value of each channel is the representative value for each channel)
And a ratio of 3.17 μm or less based on the number determined from the number distribution.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION As a raw material for the inorganic fine powder used in the present invention, silica, alumina, titania, etc. can be used. Particularly, as the raw material before the silane coupling agent treatment, fine silica powder is favorably used. To be done.

As the silica fine powder, both so-called dry method produced by vapor phase oxidation of silicon halide or dry silica called fumed silica and so-called wet silica produced from water glass can be used. But
Dry silica having less silanol groups on the surface and inside the fine silica powder and less production residues such as Na ₂ O and SO ₃ ⁻ is preferable. Further, in the case of dry silica, it is also possible to obtain a composite fine powder of silica and another metal oxide by using another metal halogen compound such as aluminum chloride and titanium chloride together with a silicon halogen compound in the production process. Also includes.

Examples of the silane coupling agent include hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, benzyldimethylchloro. Silane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilylmercaptan, trimethylsilylmercaptan, triorganosilylacrylate, vinyldimethylacetoxysilane, dimethyldiethoxysilane , Dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisiloxane, 1,3
-Divinyltetramethyldisiloxane, 1,3-diphenyltetramethyldisiloxane and 2 to 12 siloxane units per molecule with each terminal unit containing one hydroxyl group bonded to a silicon atom Examples thereof include dimethyl polysiloxane.

As a method for increasing the bulk density, a mechanical action (Henschel mixer, mix muller, etc.) is performed depending on the reaction conditions when the silicic acid fine powder is formed into a silicon halide, or before or after the treatment with a silane coupling agent. A method of aggregating particles with each other is mentioned.

The inorganic fine powder used in the present invention the specific surface area by nitrogen adsorption measured by BET method 100 m ² / g or more, particularly in the range of 150 to 400 m ² / g preferred.

The inorganic fine powder of the present invention is toner particle 1
It is preferable to add 0.05 to 3 parts by weight to 100 parts by weight.

In the present invention, pH measurement is carried out by using a pH meter using a glass electrode. 4 g of the sample is placed in a beaker, 50 cm ³ of methanol is added to wet the sample, 50 cm ³ of pure water is added, and the mixture is sufficiently stirred with a homomixer. Then the pH is measured.

The bulk density of the inorganic fine powder of the present invention was measured using a shaking specific gravity measuring device KRS-406 (manufactured by Kuramochi Kagakuki Seisakusho) according to the following procedure.

Powder is put into an attached 150 ml measuring cylinder and the upper part of the powder is scraped off.

Weight of sample in cylinder W
Accurately weighs up to 0.01.

Tapping (conditions: drop height 6 cm, tapping speed 70 times / min, tapping frequency 1250 times) is performed with a shaking specific gravity measuring device, and the powder volume V at that time is read to a unit of 1 ml.

The bulk density A is calculated by the following equation.

Bulk density A = (W / V) × 1000 (g / liter)

The electrostatic image developing toner of the present invention further comprises silicone oil or silicone varnish in an amount of 20 to 9
0% by weight (preferably 30 to 80% by weight) and a bulk density of 0.2 to 0.8 g / ml (preferably 0.25 to 7)
g / ml) and a specific surface area of 0.01 to 50 m ² / g
(Preferably 0.5 to 30 m ² / g) The second inorganic fine powder, which is characterized in that it is added in an amount of 0.02 to 1.0 part by weight to 100 parts by weight of the toner particles. This is preferable from the viewpoint of preventing character dropout, drum fusion, filming and the like.

The above-mentioned silicone oil or silicone varnish has a viscosity at 25 ° C. of 50 to 200,000 centistokes, more preferably 500 to 150,000.
The one of 00 centistokes is 1,500
It is preferably 100 to 100,000 centistokes, more preferably 3,000 to 80,000 centistokes. If it is less than 50 centistokes, it is difficult to form a large amount of silicone oil / silicone varnish into particles, the particles are not stable, and the image quality tends to deteriorate due to heat and mechanical stress. If it exceeds 200,000 centistokes, it tends to be difficult to form particles.

As the silicone oil used, for example, dimethyl silicone oil, methylphenyl silicone oil, α-methylstyrene modified silicone oil, chlorophenyl silicone oil, fluorine modified silicone oil and the like are particularly preferable. Examples of the silicone varnish include methyl silicone varnish and phenylmethyl silicone varnish. As a method for treating silicone oil / silicone varnish, for example, silica fine powder treated with a silane coupling agent and silicone oil / silicone varnish may be directly mixed using a mixer such as a Henschel mixer, You may use the method of spraying silicone oil / silicone varnish on the following silica fine powder. Alternatively, a method may be used in which the silicone oil / silicone varnish is dissolved or dispersed in an appropriate solvent and then silica fine powder is added and mixed to remove the solvent.

The bulk density of the second inorganic fine powder of the present invention is 5
Let it fall naturally into a 00 ml container from above, scrape off the part that rises from the container, measure how much g enters the container,
It was expressed by the value of [g / ml].

The toner of the present invention more preferably contains a third inorganic fine powder. By combining the third inorganic fine powder with the first and second inorganic fine powders,
The balance of density, fog and voids is further improved, and it also has the effect of preventing drum fusion. The third inorganic fine powder referred to herein is composed of an inorganic compound having the same compositional properties as the first inorganic fine powder of the present invention, and silica or titanium oxide fine powder is particularly preferably used.

Among them, the third inorganic fine powder is more preferably a fine silica powder treated with a silane coupling agent and then treated with silicone oil or silicone varnish.

The conditions for treating the fine silica powder include a silane coupling reaction as a first step to eliminate silanol groups by a chemical bond, and a second step reaction with silicone oil or silicone varnish to make the surface hydrophobic. Is formed.

The silane coupling agent used in the present invention may be the same as that used in the first inorganic fine powder of the present invention.

The treatment method of the silane coupling agent is the same as that of the first inorganic fine powder, except that the treatment for increasing the bulk density is not performed.

As the substance used for the silicone oil or silicone varnish treatment, the same substance as that used for the second inorganic fine powder may be used. Examples of the treatment method include the same method, but among them, a method in which an increase in bulk density is unlikely to occur due to agglomeration of fine powder due to treatment,
For example, a method using a sprayer is preferably used. However, it is not limited to this.

The silane coupling agent may be treated in an amount of 1 to 40 parts by weight, preferably 5 to 30 parts by weight, based on 100 parts by weight of the fine powder. The treatment amount of the silicone oil or silicone varnish solid is 1 to 23 parts by weight, preferably 5 to 20 parts by weight, per 100 parts by weight of the fine powder.

If the amount of the silane coupling agent is too small, a good solid black density cannot be obtained, and if the amount of the silane coupling agent is too large, problems such as fog occur. If the amount of the silicone oil or the silicone varnish is too small, good solid black density and the effect of improving hollow defects cannot be seen, and if it is too large, problems such as fog occur.

Characteristic values of the treated silica fine powder are as follows:
The bulk density is preferably 30 to 60 g / liter, more preferably 35 to 55 g / liter, according to the measurement method used for the first inorganic fine powder of the present invention, and the specific surface area is determined by nitrogen adsorption measured by the BET method. Those in the range of 80 to 140 m ² / g are preferable, and more preferably 90 to 130 m ²
/ G. Further, it is preferable to use 0.05 to 1.5 parts by weight, preferably 0 to 1.3 parts by weight of silica fine powder with respect to 100 parts by weight of the magnetic toner.

The magnetic substance used in the toner for developing an electrostatic image of the present invention includes metal oxides containing elements such as iron, cobalt, nickel, copper, magnesium, manganese, aluminum and silicon. Among them, ferric oxide, γ-
Those containing iron oxide as a main component such as iron oxide are preferable. Further, from the viewpoint of improving the fluidity of the toner for developing an electrostatic image and controlling the charging property, it is preferable to contain a silicon atom. In particular, when the toner particles have a small diameter, the fluidity of the toner particle base material decreases, so that sufficient fluidity cannot be obtained and good chargeability cannot be obtained simply by adding the above-mentioned inorganic fine powder of the present invention. There may be cases where it is difficult to achieve the purpose of. The content of silicon atoms is 0.
The content is preferably 2 to 2.0% by weight,
If it is less than 2, sufficient fluidity cannot be obtained, which causes adverse effects such as deterioration of character sharpness and low solid black density. 2.0
If it is contained in a larger amount, the image density is likely to be lowered particularly in a high temperature and high humidity environment. More preferably, it is 0.3 to 1.7% by weight. In particular, it is more preferable that the surface of the magnetic substance contains 0.05 to 0.5% by weight of silicon atoms.

The silicon atom may be added in the form of a water-soluble silicon compound at the time of forming the magnetic substance. After the magnetic substance is formed, filtered and dried, it is added in the form of a silicic acid compound and fixed on the surface with a mix muller or the like. May be. The particles of these magnetic materials have a BET specific surface area by the nitrogen adsorption method of preferably 2 to 30.
m ² / g is good, especially 3~28m ² / g is good. Further, magnetic particles having a Mohs hardness of 5 to 7 are preferable.

The shape of the magnetic particles may be octahedron, hexahedron, sphere, needle, scale, etc., but those having less anisotropy such as octahedron, hexahedron, sphere, and amorphous are preferable.
In particular, it is preferable that the sphericity Ψ of the magnetic particles is 0.8 or more in order to increase the image density. The average particle size of the magnetic particles is preferably 0.05 to 1.0 μm, more preferably 0.1 to 0.6 μm, and particularly preferably 0.1 to 0.4 μm.

The content of the magnetic material in the electrostatic image developing toner is 30 to 200 parts by weight, preferably 60 to 200 parts by weight, and more preferably 70 to 1 part by weight per 100 parts by weight of the binder resin.
50 parts by weight is good. If the amount is less than 30 parts by weight, it is inferior in terms of transportability, and the toner layer on the developer carrying member tends to have unevenness to cause image unevenness, and further, the image density tends to decrease due to increase in tribo of the magnetic toner. was there. on the other hand,
If the content of the magnetic material exceeds 200 parts by weight, there is a tendency that a problem occurs in fixability.

As described above, the electrostatic image developing toner of the present invention comprises
As described above, the silicon fine particles are contained in the inorganic fine powder and the magnetic substance, but the content of the silicon atom in the toner for developing an electrostatic image is 0.
The content in the range of 6 to 2.8% by weight is better for achieving the object of the present invention. When it is less than 0.6% by weight, the toner of the present invention cannot obtain good fluidity and is likely to cause problems such as low solid black density. When it is more than 2.8% by weight, the image density is low at high temperature and high humidity.
Poor fixing and other adverse effects occur.

The amount of silicon atoms in the magnetic iron oxide or the toner of the present invention is determined by the fluorescent X-ray analyzer SYSTEM308.
0 (manufactured by Rigaku Denki Kogyo Co., Ltd.) is used and JIS K01
According to 19 "General rules for fluorescent X-ray analysis", measurement was carried out by fluorescent X-ray analysis.

In the electrostatic image developing toner of the present invention, it is preferable to use an organometallic compound as a charge control agent.
Among the organometallic compounds, those containing an organic compound which is particularly highly vaporizable and sublimable as a ligand and a counter ion are useful.

As such a metal complex, there is an azo metal complex represented by the following general formula.

[0053]

Embedded image

In the formula, M represents a coordination center metal, and Cr, Co, Ni, Mn, Fe, Al, Ti, S having a coordination number of 6 are used.
c, V, etc. Ar is an aryl group, and examples thereof include a phenyl group and a naphthyl group, which may have a substituent. Examples of the substituent in this case include a nitro group, a halogen group, a carboxyl group, an anilide group, an alkyl group having 1 to 18 carbon atoms, and an alkoxy group. X, X ', Y,
Y'is -O-, -CO-, -NH-, -NR- (R is an alkyl group having 1 to 4 carbon atoms). K ⁺ is hydrogen ion,
It indicates sodium ion, potassium ion, ammonium ion, aliphatic ammonium ion, or a mixed ion of any of these.

The specific examples of the complexes preferably used in the present invention are shown below.

[0056]

Embedded image

[0057]

[Chemical 6]

[0058]

[Chemical 7]

Among these, in the toner for developing an electrostatic image having the particle size distribution of the present invention, the compound shown in (b) or (c) is particularly used to secure the fluidity of the toner, and the sharpness of characters,
The image density is also good, and it is more preferably used.

The compound is preferably added in the range of 0.2 to 5 parts by weight with respect to 100 parts by weight of the toner.

Examples of the kind of the binder resin used in the present invention include polystyrene; homopolymers of styrene substitution products such as poly-p-chlorostyrene and polyvinyltoluene; styrene-p-chlorostyrene copolymers; Styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-acrylic acid ester copolymer,
Styrene-methacrylate copolymer, styrene-
α-Chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer Styrene-based copolymers such as styrene-isoprene copolymer and styrene-acrylonitrile-indene copolymer; polyvinyl chloride, phenol resin, natural modified phenol resin, natural resin modified maleic acid resin, acrylic resin, methacrylic resin, poly Vinyl acetate, silicone resin, polyester resin, polyurethane, polyamide resin, furan resin, epoxy resin, xylene resin, polyvinyl butyral, terpene resin, coumarone indene resin, petroleum resin and the like can be used. Also,
Crosslinked styrenic resins are also preferred binder resins.

Examples of the comonomer for the styrene monomer of the styrene copolymer include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, and the like.
Didecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, etc. A monocarboxylic acid having a heavy bond or a substituted product thereof;
For example, a dicarboxylic acid having a double bond such as maleic acid, butyl maleate, methyl maleate, dimethyl maleate, and the like; and vinyl chloride;
Vinyl esters such as vinyl acetate, vinyl benzoate and the like, for example, ethylene olefins such as ethylene, propylene, butylene and the like; vinyl ketones such as vinyl methyl ketone and vinyl hexyl ketone;
For example, vinyl monomers such as vinyl methyl ether, vinyl ethyl ether, and vinyl isobutyl ether; and the like, or a vinyl monomer such as vinyl monomers, may be used alone or in combination. Here, as the cross-linking agent, a compound having two or more polymerizable double bonds is mainly used, for example, an aromatic divinyl compound such as divinylbenzene, divinylnaphthalene or the like; for example, ethylene glycol diacrylate, ethylene glycol Dimethacrylate,
Carboxylic acid esters having two double bonds such as 1,3-butanediol dimethacrylate; divinyl compounds such as divinylaniline, divinyl ether, divinyl sulfide and divinyl sulfone; and compounds having three or more vinyl groups; Can be used alone or as a mixture.

Further, as the binder resin of the electrostatic image developing toner used for pressure fixing, low molecular weight polyethylene,
Examples include low molecular weight polypropylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer, higher fatty acid, polyamide resin, and polyester resin.
These are preferably used alone or as a mixture.

Further, it is also preferable to include the following waxes in the toner particles from the viewpoint of improving the releasability from the fixing member during fixing and the fixing property. Paraffin wax and its derivatives, microcrystalline wax and its derivatives, Fischer-Tropsch wax and its derivatives, polyolefin wax and its derivatives, carnauba wax and its derivatives, etc., with derivatives including oxides and block copolymers with vinyl monomers , Graft-modified products.

As other additives, alcohols, fatty acids, acid amides, esters, ketones, hydrogenated castor oil and its derivatives, plant wax, animal wax, mineral wax, petrolactam and the like can be used.

A known method is used to prepare the toner for developing an electrostatic image of the present invention. For example, a binder resin, a wax, a metal salt or a metal complex, a pigment as a colorant, a dye, or a magnetic substance, and if necessary, a charge control agent, other additives, etc. are sufficiently mixed by a mixer such as a Henschel mixer or a ball mill. After mixing, melt kneading using a heat kneader such as a heating roll, kneader, or extruder to make the resins compatible with each other, and disperse or dissolve the metal compound, pigment, dye, and magnetic substance, and cool. After solidification, crush,
The toner according to the present invention can be obtained by performing classification. In the classification step, it is preferable to use a multi-division classifier in terms of production efficiency.

Further, an image forming method and apparatus according to the present invention will be described with reference to FIG.

The surface of the photoconductor is negatively charged by the primary charger 302, and a digital latent image is formed by image scanning by exposure 305 with a laser beam.
The latent image is reversely developed with the one-component magnetic developer 310 of the developing device 309 including the developing sleeve 304 containing 11 and a magnet. Alternate bias, pulse bias and / or DC bias are applied by the bias applying means 312 between the conductive substrate of the photosensitive drum 301 and the developing sleeve 304 in the developing section. When the transfer paper P is conveyed and reaches the transfer portion, the roller transfer means 302 charges the transfer paper P from the back surface (the surface opposite to the photosensitive drum side) of the transfer paper P by the voltage application means 314, thereby developing the image on the photosensitive drum surface. The (toner image) is electrostatically transferred onto the transfer paper P.
The transfer paper P separated from the photosensitive drum 301 is subjected to a fixing process by the heating and pressure roller fixing device 307 in order to fix the toner image on the transfer paper P.

The one-component developer remaining on the photosensitive drum after the transfer process is removed by a cleaning device 308 having a cleaning blade. The photosensitive drum 301 after cleaning is erased by the erase exposure 306, and again,
The process starting from the charging process by the primary charger 302 is repeated.

[0070]

EXAMPLES Specific examples of the present invention will be shown below. "Part"
Means parts by weight.

Example 1 Binder resin 100 parts Magnetic substance M1 (Fe ₃ O ₄ having a silicon atom content of 0.12% by weight) 100 parts Monoazo dye metal complex (formula a) 2 parts Wax 5 parts

The above constituent materials were mixed and dispersed by a Henschel mixer, and melt-kneaded by a twin-screw extruder.
The kneaded product was cooled, coarsely pulverized, finely pulverized by a pulverizer using a jet stream, and further classified by an air classifier to obtain toner particles.

To 100 parts of the toner particles, an original silica (specific surface area = 300 m ² / g) was treated with hexamethyldisilazane, pH = 5.9, and bulk density = 72 g / liter of inorganic fine powder A (specific ratio: Surface area = 197 m ² / g) 1.2
Parts, mixed with a Henschel mixer, and weight average diameter X =
Thus, a toner for developing an electrostatic image of 5.8 (μm) and Y = 17.5 (%) was obtained. The silicon atom content in the toner was 0.58% by weight.

The toner obtained is used as a printer LJ manufactured by HP.
It was put in −IV and evaluated according to the following image evaluation method. The results are shown in Table 1.

The image quality is evaluated in a normal temperature and normal humidity environment (23.
During the durability (about 5000 sheets) of LJ-IV at 5 ° C. and 60%), a check was periodically performed and evaluated.

Character sharpness: Using a check sample at the time of 1000 sheets, about 2 mm square "electric" characters are about 3
It was magnified 0 times and judged according to the evaluation criteria of FIG. Ranks 2 and 4 are intermediate levels of ranks 1, 3, 3 and 5, respectively.

Solid black density: 20 from the initial to 5,000 sheets
A total of 26 samples for every 0 sheets were measured by a Macbeth densitometer and shown as an average value.

Character voids: General characters are printed on 128 g / m ² thick paper, initial 1000 sheets, 2000 sheets, 3 sheets
The average of 6 samples of 000 sheets, 4000 sheets and 5000 sheets was evaluated. Rank 5: Good (see (a) of FIG. 2), Rank 1: Not practically possible (see (b) of FIG. 2), Rank 3:
Practically acceptable, ranks 4 and 2 are intermediate levels of ranks 5 and 3 and ranks 3 and 1, respectively.

Example 2 Magnetic material M2 (Fe ₃ having a silicon atom content of 0.52% by weight)
O ₄ ) was used, the same constituent materials as in Example 1 were used, and X = 5.8 (μ) from the same manufacturing method as in Example 1.
m) and Y = 17.6 (%) to obtain a toner for developing an electrostatic charge image. The silicon atom content in the toner was 0.77% by weight. The evaluation was performed in the same manner as in Example 1. Table 1 shows the results
Shown in

Example 3 Using the same constituent materials as in Example 2, the inorganic fine powder A
From the same manufacturing method except that 5 parts were added, X = 5.8 (μ
m) and Y = 19.0 (%) to obtain a toner for developing an electrostatic charge image. The silicon atom content in the toner was 0.92% by weight. The evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

Example 4 By the same manufacturing method as in Example 3, X = 5.1 (μm) and Y = 2.
3.5 (%) of toner for developing electrostatic image was obtained. The silicon atom content in the toner was 0.91% by weight. The evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

Example 5 X = 5.7 (μm), in the same manner as in Example 3, except that the monoazo dye metal complex having the formula (b) was used.
A toner for developing an electrostatic image of Y = 19.1 (%) was obtained. The silicon atom content in the toner was 0.92% by weight.
The evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

Example 6 X = 5.7 (μm) was obtained in the same manner as in Example 3 except that the monoazo dye metal complex having the formula (c) was used.
Y = 19.3 (%) of an electrostatic charge image developing toner was obtained. The silicon atom content in the toner was 0.92% by weight.
The evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

Example 7 Using the same toner particles as in Example 2, the toner particles 1
1.5 parts of the inorganic fine powder A and 100 parts of the second inorganic fine powder a [silica containing 60% by weight of silicone oil,
0.2 parts of bulk density 0.4 g / ml, specific surface area 3.0 m ² / g] were added and mixed with a Henschel mixer, and X = 5.
A toner for developing an electrostatic charge image of 9 (μm) and Y = 19.5 (%) was obtained. The silicon atom content in the toner was 0.96% by weight. The evaluation was performed in the same manner as in Example 1 below. The results are shown in Table 1.

Example 8 To the same toner particles as in Example 6, two kinds of inorganic fine powder were added and mixed in the same manner as in Example 7, and X = 5.9 (μ
m), Y = 19.7 (%), to obtain an electrostatic charge image developing toner. The silicon atom content in the toner was 0.97% by weight. The evaluation was performed in the same manner as in Example 1 below. The results are shown in Table 1.

Example 9 The same toner particles as in Example 2 were treated with hexamethyldisilazane treated with original silica (specific surface area = 300 m ² / g) in place of the inorganic fine powder A to obtain a specific surface area of 190 m ² / g. 1.5 parts of inorganic fine powder B [pH = 6.3, bulk density = 165 g / liter] of X was added and mixed, and X = 5.8 (μm), Y
= 18.8 (%) of the electrostatic charge image developing toner was obtained. The silicon atom content in the toner was 0.92% by weight. The evaluation was performed in the same manner as in Example 1 below. The results are shown in Table 1.

Example 10 In the same manner as in Example 3 except that M3 (Fe ₃ O ₄ having a silicon atom content of 1.75% by weight) was used as the magnetic material,
A toner for developing an electrostatic image with X = 5.8 (μm) and Y = 18.7 (%) was obtained. The content of silicon atoms in the toner is 1.
It was 22% by weight. The evaluation was performed in the same manner as in Example 1 below. The results are shown in Table 1.

Comparative Example 1 100 parts of the toner particles used in Example 1 were mixed with the original silica used in Example 1, [inorganic fine powder C (pH = 5.5,
Bulk density = 45 g / liter] is added and mixed with a Henschel mixer, and X = 5.8 (μm), Y =
17.5 (%) of toner for developing electrostatic image was obtained. The silicon atom content in the toner was 0.56% by weight. The evaluation was performed in the same manner as in Example 1 below. The results are shown in Table 1.

Comparative Example 2 100 parts of the toner particles used in Example 1 were treated with trimethylsilane of original silica to obtain an inorganic fine powder D [pH =
3.0, bulk density = 58 g / liter] was added in the same manner as in Example 1 except that X = 5.8 (μm),
Y = 17.6 (%) of an electrostatic charge image developing toner was obtained. The silicon atom content in the toner was 0.57% by weight.
The evaluation was performed in the same manner as in Example 1 below. The results are shown in Table 1.

Comparative Example 3 The same constituent material as in Example 1 was used except that a chromium complex of salicylic acid was used as the charge control agent, and toner particles having a larger particle size were obtained by the same production method, and then the inorganic fine powder was used. D
Was added in the same manner as in Comparative Example 2, and X = 6.7 (μm) and Y =
A toner for developing an electrostatic image of 5.0% was obtained. The silicon atom content in the toner was 0.57% by weight. The evaluation was performed in the same manner as in Example 1 below. The results are shown in Table 1.

Example 11 Using the same toner particles as in Example 2, the toner particles 1
0.8 parts of inorganic fine powder A and 0.2 parts of second inorganic fine powder a are added to 00 parts, and third inorganic fine powder S is further added.
[100 parts of fine silica (specific surface area: 200 m ² / g) and 10 parts of hexamethyldisilazane were treated with dimethyl silicone oil (100 cS).
t), a bulk density of 45 g / liter, a specific surface area of 120 m ² / g] was added in an amount of 0.7 part and mixed with a Henschel mixer, and X = 5.8 (μm), Y = 19.2 (%).
To obtain a toner for developing an electrostatic image.

When evaluated in the same manner as in Example 1, good results were obtained with respect to "character sharpness", "solid black image density" and "blank void", and durability was further obtained for 5000 sheets. When the occurrence of white spots in the solid black image afterwards was evaluated, the white spots were found to be small, and compared to Examples 2 and 7, the effect of preventing toner fusion on the photosensitive drum was observed.

[0093]

[Table 1]

[0094]

INDUSTRIAL APPLICABILITY The present invention provides an image having a good balance of sharpness of characters, solid black density and voids in characters by adding a specific inorganic fine powder to a toner having a particle size distribution in a small diameter range. It has become possible.

[Brief description of drawings]

FIG. 1 is a diagram based on a magnified photograph of a general character having a length and width of about 2 mm, showing the level of sharpness of the character.

FIG. 2 is a diagram schematically showing an example (a) in which a transfer state is good with general characters and an example (b) in which a transfer state is poor.

FIG. 3 is a diagram schematically showing a specific example of an image forming method and an image forming apparatus suitable for the present invention.

[Explanation of symbols]

 301 Photoreceptor 302 Charging Means 303 Transfer Means 304 Toner Carrier 305 Latent Image Forming Means 306 Erase Exposure 307 Heat Press Roller Fixer 308 Cleaning Means 309 Developing Means 310 Electrostatic Image Developing Toner 311 Magnetic Blades 312 Bias Applying Means 313 Voltage Application means P Transfer paper

Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display area G03G 9/08 375

Claims (12)

[Claims] 1. A toner for developing an electrostatic charge image, comprising at least toner particles and an inorganic fine powder, wherein the particle size distribution of the toner for developing an electrostatic charge image is calculated from a weight average diameter (D ₄ ) of X (μm) and a number distribution. When the number% of 3.17 μm or less based on the obtained number is defined as Y (%), the following condition −5X + 35 ≦ Y ≦ −25X + 180 3.5 ≦ X ≦ 6.5 is satisfied, and the inorganic fine powder is a silane cup. Treated with a ring agent,
Bulk density of 60-180 g / liter and pH of 4.5-
A toner for developing an electrostatic charge image, which is 8.5. 2. The toner for developing an electrostatic image according to claim 1, wherein 0.05 to 3 parts by weight of the inorganic fine powder is added to 100 parts by weight of the toner particles. 3. The toner for developing an electrostatic image contains 20 to 90% by weight of silicone oil or silicone varnish, has a bulk density of 0.2 to 0.8 g / ml and a specific surface area of 0.01 to 50 m. ^The toner for developing an electrostatic charge image according to claim 1 or 2, containing a second inorganic fine powder having a content of ² / g. 4. The toner according to claim 3, wherein 0.02 to 1 part by weight of the second inorganic fine powder is added to 100 parts by weight of the toner particles. . 5. A third inorganic having a bulk density of 30 to 60 g / liter and a specific surface area of 80 to 140 m ² / g, which is obtained by treating the toner with a silane coupling agent and then treated with silicone oil or silicone varnish. The electrostatic charge image developing toner according to claim 1, further comprising a fine powder. 6. The electrostatic image developing device according to claim 5, wherein 0.05 to 3 parts by weight of the third inorganic fine powder is added to 100 parts by weight of the toner particles. toner. 7. The toner particles according to claim 1, wherein the toner particles contain a magnetic material, and silicon atoms are contained in an amount of 0.2 to 2.0% by weight based on the magnetic material. The toner for developing an electrostatic charge image according to any one of claims 1. 8. The toner particles contain at least a binder resin and a magnetic material, and the magnetic material is contained in an amount of 70 to 150 parts by weight with respect to 100 parts by weight of the binder resin. Item 7. The toner for developing an electrostatic image according to Item 7. 9. The electrostatic charge image developing toner according to claim 7, wherein silicon atom is contained in an amount of 0.6 to 2.8% by weight based on the electrostatic charge image developing toner. 8. The toner for developing an electrostatic charge image according to item 8. 10. The toner for developing an electrostatic charge image according to claim 1, wherein the toner particles contain an organometallic compound represented by the following formula as a charge control agent. . Embedded image 11. The toner for developing an electrostatic charge image according to claim 1, wherein the toner particles contain an organometallic compound represented by the following formula as a charge control agent. . Embedded image 12. The toner for developing an electrostatic charge image according to claim 1, wherein the toner particles contain an organometallic compound represented by the following formula as a charge control agent. Embedded image