JPH1010772A - Toner for developing electrostatic latent image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a toner for developing an electrostatic latent image excellent in environmental stability and flowability, not causing the problem of the sticking of a toner component to a photoreceptor and the problem of voids in a solid image even at the time of repetitive use, capable of giving a superior image and fit to form a full-color image. SOLUTION: Colored resin particles contg. at least a colorant and a resin binder are mixed with hydrophobic fine silica particles having 10-50nm number average particle diameter and a hydrophobicity of >=50, hydrophobic fine titania particles having 10-90nm number average particle diameter and a hydrophobicity of >=50 and inorg. fine particles having 100-3,000nm number average particle diameter. The total amt. of the silica and titania particles added is 1-3wt.% of the amt. of the colored resin particles and the amt. of the inorg. fine particles added is 0.5-3wt.% of the amt. of the colored resin particles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a toner for developing an electrostatic latent image, and more particularly to a toner for developing an electrostatic latent image used in a full-color image forming apparatus such as a full-color copying machine and a full-color laser beam printer.

[0002]

2. Description of the Related Art Conventionally, an electrostatic latent image formed on an electrostatic latent image carrier such as a photosensitive member is developed using toner, and the toner image is transferred onto a recording member such as recording paper. The forming method is widely used in copiers, printers, facsimile machines and the like, and has recently been adopted in full-color image forming apparatuses that reproduce a multicolor image by superimposing a plurality of color toners.

In such an image forming apparatus, an area gradation method and a laser intensity modulation method are employed for reproducing a multi-gradation image. Also, high fluidity is required for the toner.However, especially in the laser intensity modulation method, gradation reproduction is performed by changing the toner adhesion amount corresponding to the change in the charge amount of the latent image due to laser intensity modulation, so higher fluidity is required. is necessary.

Further, a full-color toner needs to have a light-transmitting property, so that a binder resin used for toner particles needs to have a sharp melt property. However, toner having such characteristics tends to cause toner agglomeration due to stress in the developing device during printing, and the likelihood of white spots due to the agglomerates in solid images. There is.

Further, such a toner has a small variation in the amount of charge of the toner with respect to environmental changes such as temperature and humidity, and does not cause sticking (BS) of the toner component to the photosensitive member. It is required to have characteristics. However, there are various technical problems to satisfy all the above-mentioned characteristics. For example, in order to improve the fluidity, it is effective to externally add silica fine particles to the toner and increase the amount thereof, but the environmental stability is reduced. When titania fine particles or alumina fine particles are added to improve environmental stability, the total amount of external additives added to the toner increases, so that the amount of external additives that pass through the cleaning blade and adhere to the photoreceptor surface also increases. The external additive becomes a nucleus and adheres to the other toner components so as to pull off the edge during cleaning, and the problem of fixation (BS) to the photoreceptor becomes remarkable. If the amount of the external additive is reduced so that BS does not occur, not only does the fluidity become insufficient, but also toner agglomeration occurs due to stress in the developing device during printing, causing This causes the problem of white spots.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrostatic latent image developing toner which solves the above-mentioned problems. That is, an object of the present invention is to provide a toner for developing an electrostatic latent image which is excellent in environmental stability, does not cause image deterioration due to changes in humidity or temperature, and solves the problem such as white spots on an image. Another object of the present invention is to provide a toner for developing an electrostatic latent image which is excellent in fluidity and does not cause a problem of adhesion of a toner component to a photoreceptor. Another object of the present invention is to provide a toner for developing an electrostatic latent image suitable for forming a full-color image.

[0007]

According to the present invention, there is provided a colored resin particle containing at least a colorant and a binder resin, comprising hydrophobic silica fine particles having a number average particle diameter of 10 to 50 nm and a degree of hydrophobicity of 50 or more. , Number average particle size is 10 to 90
hydrophobic titania fine particles having a hydrophobicity of 50 or more in nm,
Inorganic fine particles having a number average particle diameter of 100 to 3000 nm are added and mixed, and the total added amount of the silica fine particles and the titania fine particles is 1 to 3% by weight based on the colored resin particles. The present invention relates to a toner for developing an electrostatic latent image, the amount of which is 0.3 to 3% by weight with respect to the colored resin particles. The present invention also relates to an electrostatic latent image developing toner used in a full-color image forming apparatus that reproduces a multicolor image using magenta toner, cyan toner, yellow toner, and black toner.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a method in which silica fine particles and titania fine particles which are externally added to and mixed with toner particles (colored resin particles) have a specific number average particle diameter and a specific degree of hydrophobicity. The above-mentioned problem is solved by using an inorganic fine particle having a specific number average particle diameter in addition to using it in an amount. In the present invention, the number average particle diameter of the primary particles is 10 to 50 nm,
Preferably 10 to 30 nm, more preferably 10 to 25
Hydrophobic silica fine particles having a hydrophobicity of 50 or more, preferably 55 to 90 in nm are used. By using such silica fine particles, it is possible to improve the fluidity of the toner, improve the gradation reproducibility, and impart the lubricating property of the cleaning blade to the photoconductor. Average particle size is 5
If it is larger than 0 nm, the effect of improving the fluidity of the toner and the effect of improving the lubricity of the cleaning blade become insufficient. On the other hand, when the average particle size is smaller than 10 nm, embedding in toner particles is apt to occur, and the change in powder characteristics at the time of printing endurance becomes large, and environmental stability is lowered. If the degree of hydrophobicity is lower than 50, fog occurs on a white background portion of an image under a high temperature and high humidity environment.

As the titania fine particles, the primary particles have a number average particle size of 10 to 90 nm, preferably 30 to 80 nm,
More preferably, hydrophobic titania fine particles having a diameter of 35 to 80 nm and a degree of hydrophobicity of 50 or more, preferably 55 to 90, are used. By using such titania fine particles, it is possible to solve the problem of image density reduction in a low-temperature and low-humidity environment due to the silica fine particles, to prevent the problem of white spots, and to improve the heat-resistant storage stability. If the average particle size is larger than 90 nm, the coverage of the toner is reduced, and the environmental stability, heat storage stability, and the effect of preventing white spots are reduced. If the average particle size is smaller than 10 nm, the agitation stress in the developing device during printing use is reduced. As a cause, titania is easily embedded in the toner particles. As a result, the effect of suppressing the aggregation of the developer is reduced, and white spots are easily generated in a solid image.

As such titania fine particles, small particles having a number average particle diameter of 10 to 30 nm and a number average particle diameter of 3 to 30 nm are used.
Large-diameter particles of 0 to 90 nm, preferably 35 to 80 nm may be used in combination. The small-diameter particles contribute to the improvement of the fluidity, and the large-diameter particles more effectively contribute to the heat-resistant storage property and the effect of preventing white spots.

As the titania fine particles, anatase titania, rutile titania, amorphous titania and the like can be used, but anatase titania is preferable.

The total amount of the silica fine particles and titania fine particles is 1 to 3% by weight, preferably 1.2 to 2.5% by weight, based on the colored resin particles. If the amount is less than 1% by weight, the effect of preventing white spots becomes insufficient, and if it exceeds 3% by weight, BS is likely to be generated. The addition weight ratio of the silica fine particles and the titania fine particles cannot be said unconditionally because they vary depending on the respective particle diameters and the like. However, it is preferable to use them in a ratio of 9: 1 to 1: 9, preferably 7: 3 to 3: 7. desirable.

The silica fine particles and the titania fine particles are surface-treated with a hydrophobizing agent. As such a hydrophobizing agent, a silane coupling agent, a titanate coupling agent, silicone oil, silicone varnish and the like can be used. Examples of the silane coupling agent include hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, benzyldimethylchlorosilane, methyltrimethoxysilane, methyltriethoxysilane, and isobutyl Trimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, trimethylmethoxysilane, hydroxypropyltrimethoxysilane, phenyltrimethoxysilane, n-butyltrimethoxysilane, n-hexadecyltrimethoxysilane, n-octadecyltrimethoxysilane, Vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, etc. A possible use, silicone - as is N'oiru, such as dimethylpolysiloxane, methylhydrogenpolysiloxane, methylphenyl polysiloxane can be used.

In order to surface-treat a silica or titania base material with the above-mentioned hydrophobizing agent, for example, the hydrophobizing agent is diluted with a solvent, the above-mentioned diluent is added to the base material and mixed, and this mixture is heated and dried. It can be carried out by a dry method of post-crushing, a wet method of dispersing the base material in an aqueous system to form a slurry, adding and mixing a hydrophobizing agent, heating and drying and then crushing. In particular, for the titania, it is preferable to perform the hydrophobic treatment in an aqueous system from the viewpoint of the uniformity of the surface treatment of the hydrophobizing agent, the prevention of aggregation of the titania particles, and the like.

In the present invention, the degree of hydrophobicity is measured by a methanol wettability method. First, methanol is dropped into water in which a sample is dispersed, and the weight of methanol required to wet the entire sample is measured. The percentage of the weight of methanol in water and methanol at this time was defined as the degree of hydrophobicity.

The toner of the present invention has a number average particle size of 100 to 3000 in addition to the titania and silica.
nm, preferably 100 to 1000 nm of inorganic fine particles are added and mixed. By using such inorganic fine particles in combination, it is possible to eliminate BS which becomes a problem when the total amount of silica and titania fine particles is 1% by weight or more from the viewpoint of preventing white spots and improving the fluidity. This is presumably because inorganic fine particles have a function of reducing the amount of silica and titania particles that pass through the blade during blade cleaning. When the average particle diameter of the inorganic fine particles is smaller than 100 nm, the effect of preventing BS becomes insufficient, and when the average particle diameter is larger than 3000 nm, when image formation is repeatedly performed, at the time of blade cleaning, or at the time of press transfer by a transfer drum in a full-color image forming apparatus or the like. The photoconductor is easily damaged.

Such inorganic fine particles include silica,
Fine particles such as titania, alumina, barium titanate, magnesium titanate, calcium titanate, strontium titanate, chromium oxide, cerium oxide, magnesium oxide, and zirconium oxide can be used alone or in combination of two or more. In particular, fine particles containing sintered aggregates of primary particles are preferable, and such particles have a number average particle diameter of 100 to 1000 nm, preferably 100 to 800 nm.
Strontium titanate fine particles of nm are desirable.

The inorganic fine particles are 0.3 to the colored resin particles.
To 5.0% by weight, preferably 0.5 to 3.0% by weight. If the amount is less than 0.3% by weight, the effect of preventing BS is insufficient. If the amount is more than 5% by weight, the damage to the photoconductor and the effect on the chargeability of the toner are undesirably increased.

As the binder resin used in the toner of the present invention, known resins can be used, for example, styrene resins, acrylic resins such as alkyl acrylates and alkyl methacrylates, styrene-acrylic copolymer resins, and polyester resins. Resins, epoxy resins, silicon resins, olefin resins, amide resins and the like can be mentioned, and these can be used alone or in combination.

In the present invention, the binder resin used for full-color toners such as cyan toner, magenta toner, yellow toner and black toner has a number average molecular weight (Mn) of 3,000 to 6000, preferably 35 to 6,000.
00 to 5500, the ratio Mw / Mn of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 2 to 6, preferably 2.5
~ 5.5, glass transition point 50 ~ 70 ° C, preferably 5
It is preferable to use a polyester resin or an epoxy resin having a temperature of 5 to 65 ° C and a softening point of 90 to 110 ° C, preferably 90 to 105 ° C, and use it as a negatively chargeable toner.

The number average molecular weight of the binder resin is 3000
If it is smaller than that, the image portion is peeled off when a full-color solid image is bent, causing image defects (bending fixability is deteriorated). If it is larger than 6000, the heat melting property at the time of fixing is reduced and the fixing strength is reduced. I do. If Mw / Mn is less than 2, high-temperature offset is likely to occur, and if it is greater than 6, sharp melt characteristics at the time of fixing deteriorate, and the light transmittance of the toner and the color mixing at the time of full-color image formation decrease. I will. On the other hand, if the glass transition point is lower than 50 ° C., the heat resistance of the toner becomes insufficient, and the toner tends to aggregate during storage. If the glass transition point is higher than 75 ° C., the fixability decreases and the color mixture during full-color image formation. Is reduced. If the softening point is lower than 90 ° C., high-temperature offset is likely to occur, and 1
If the temperature is higher than 10 ° C., the fixing strength, the light transmittance, the color mixing, and the gloss of a full-color image are reduced. As the polyester resin, those containing etherified diphenols as an alcohol component and aromatic dicarboxylic acids as an acid component can be used.

The above etherified diphenols include:
For example, polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2) -2,2-bis (4-hydroxyphenyl) propane and the like can be mentioned.

In addition to the etherified diphenols, diols such as ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol and the like can be used. Kind,
Sorbitol, 1,2,3,6-hexanetetrol,
1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,2
4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2
-Methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene and the like may be used.

As the aromatic dicarboxylic acids, aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid, acid anhydrides thereof and lower alkyl esters thereof can be used.

Further, aliphatic dicarboxylic acids such as fumaric acid, maleic acid, succinic acid, alkyl or alkenyl succinic acids having 4 to 18 carbon atoms, and aliphatic dicarboxylic acids such as acid anhydrides or lower alkyl esters thereof are used. You may.

Also, 1,2,4-benzenetricarboxylic acid (trimellitic acid), 1,2,5-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid,
2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanenetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, Polyvalent carboxylic acids such as 4-cyclohexanetricarboxylic acid, tetra (methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid, anhydrides thereof and lower alkyl esters are used as acid values of polyester resins. Adjustment of,
For the purpose of improving the resin strength, a small amount may be used as long as the translucency is not impaired. When used for a black toner, it is not necessary to particularly consider the translucency.

As the colorant used in the toner of the present invention,
Known ones can be used and are not particularly limited.

It is preferable that the colorant used in the color toner has improved dispersibility of the colorant by a master batch process or a flushing process. The content of the colorant is preferably 2 to 15 parts by weight based on 100 parts by weight of the binder resin.

The toner of the present invention may contain desired additives such as a charge control agent, a magnetic powder, and a wax, in addition to the coloring agent.

Known charge control agents can be used, and are not particularly limited. The charge control agent used for the color toner is the color tone of the color toner,
A colorless, white or light-colored charge control agent which does not adversely affect light transmittance can be used. It is preferable to use a charge control agent such as a system compound. The salicylic acid metal complex is described in, for example,
JP-A-127726, JP-A-62-145255 and the like; calixarene-based compounds described in, for example, JP-A-2-201378 and the like; -221
No. 967 and the like, and fluorine-containing quaternary ammonium salt-based compounds are described, for example, in JP-A-3-1162.
Publications described in Japanese Patent Application Laid-Open No. H10-260, etc. can be used.

When such a charge control agent is added,
It is preferable to use 0.1 to 10 parts by weight, preferably 0.5 to 5.0 parts by weight, based on 100 parts by weight of the binder resin.

The volume average particle diameter of the toner according to the present invention is preferably adjusted to 5 to 10 μm, more preferably 6 to 9 μm, from the viewpoint of high definition reproducibility of an image.

The toner of the present invention can be used as a two-component developer toner which is used by mixing with a carrier, or as a one-component developer toner which does not use a carrier.

As the carrier used in combination with the toner of the present invention, those conventionally known as carriers for two-component developers can be used. For example, carriers made of magnetic particles such as iron and ferrite can be used. A resin-coated carrier obtained by coating such magnetic particles with a resin,
Alternatively, a binder-type carrier formed by dispersing a magnetic fine powder in a binder resin or the like can be used. Among these carriers, a silicone resin as a coating resin,
Use of a resin-coated carrier using a copolymer resin (graft resin) of an organopolysiloxane and a vinyl monomer or a polyester-based resin, or a binder-type carrier using a polyester-based resin as a binder resin is a toner spent. And the like. Particularly, a carrier coated with a resin obtained by reacting an isocyanate with a copolymer resin of an organopolysiloxane and a vinyl-based monomer has excellent chargeability, durability, and environmental resistance to a negatively chargeable toner. It is preferable from the viewpoint of stability and spent resistance. As the vinyl monomer, it is necessary to use a monomer having a substituent such as a hydroxyl group reactive with isocyanate. The carrier has a volume average particle size of 20 to 100 μm.
m, preferably 30 to 80 μm, from the viewpoints of ensuring high image quality and preventing carrier adhesion.

[0035]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to examples, but the present invention is not limited thereto.

(Production of Polyester Resin) A 2-liter four-necked flask was equipped with a reflux condenser, a water separator, a nitrogen gas inlet tube, a thermometer, and a stirrer. , 2) -2,2
-Bis (4-hydroxyphenyl) propane, polyoxyethylene (2,0) -2,2-bis (4-hydroxyphenyl) propane, fumaric acid and terephthalic acid in a molar ratio of 5: 5: 5: 4 The reaction was carried out by heating and stirring while introducing nitrogen into the flask. The progress of the reaction was monitored while measuring the acid value. When the acid value reached a predetermined value, the reaction was terminated.
A polyester resin having a weight average molecular weight Mw and a number average molecular weight Mn of Mw / Mn of 4.0, a glass transition point of 58 ° C, and a softening point of 100 ° C was obtained.

The number-average molecular weight and weight-average molecular weight are determined by gel permeation chromatography (807-I).
(T type: manufactured by JASCO Corporation), the column was kept at 40 ° C., tetrahydrofuran was flowed at 1 kg / cm ³ as a carrier solvent, and 30 mg of a sample to be measured was dissolved in 20 ml of tetrahydrofuran. 5m
g was introduced together with the above-mentioned carrier solvent, and determined in terms of polystyrene.

For the glass transition point, a differential scanning calorimeter (DSC-200: manufactured by Seiko Instruments Inc.) was used.
About 0 mg, the measurement was performed at a heating rate of 10 ° C./min using alumina as a reference, and the shoulder value of the main absorption peak was defined as the glass transition point.

For the softening point, use a flow tester (CF
T-500: manufactured by Shimadzu Corporation) for 1.0 g of a sample, using a die having a pore diameter of 1.0 mm and a pore length of 1.0 mm, a temperature rising rate of 3.0 ° C./min, and a preheating time of 18
The measurement was performed under the conditions of 0 seconds, a load of 30 kg, and a measurement temperature range of 60 to 140 ° C., and the temperature at which the sample flowed out by １ ／ was defined as the softening point.

(Production of Toner Particle A) The above polyester resin and cyan pigment (CI Pigment Blue 15-
3: manufactured by Toyo Ink Mfg. Co., Ltd.) and kneaded in a pressure kneader so that the weight ratio of resin to pigment was 7: 3. The obtained kneaded material was cooled and pulverized by a feather mill to obtain a pigment master batch.

93 parts by weight of the polyester resin, 10 parts by weight of the pigment masterbatch, and 2 parts by weight of a charge control agent (zinc salicylate complex: E-84: manufactured by Orient Chemical Industries) were mixed with a Henschel mixer. The mixture was kneaded with a screw extruder. The obtained kneaded product was cooled, coarsely pulverized by a feather mill, finely pulverized by a jet mill, and classified to obtain toner particles A having a volume average particle diameter of 8.0 μm.

(Production of Toner Particles B) 100 parts by weight of the above polyester resin, 3 parts by weight of carbon black (Mogal L: manufactured by Cabot), and a charge control agent (zinc salicylate complex: E-84: manufactured by Orient Chemical Industries) 2 After mixing parts by weight with a Henschel mixer, the mixture was kneaded with a twin-screw extruder. After cooling the obtained kneaded material, it was coarsely pulverized by a feather mill, finely pulverized by a jet mill, and further classified by an airflow classifier to obtain toner particles B having a volume average particle diameter of 8.0 μm.

(Adjustment of Toner) The toner particles obtained above were mixed with an external additive shown in Table 1 in an amount shown in Table 2 using a Henschel mixer.
The toners of Examples and Comparative Examples were obtained through a 00 mesh circular vibrating screen.

[0044]

[Table 1]

[0045]

[Table 2]

(Example of Carrier Production) Capacity 500 equipped with a stirrer, condenser, thermometer, nitrogen inlet tube, and dropping device
100 parts by weight of methyl ethyl ketone was charged into a ml flask. Separately, methyl methacrylate at 80 ° C under nitrogen atmosphere
36.7 parts by weight, 5.1 parts by weight of 2-hydroxyethyl methacrylate, 58.2 parts by weight of 3-methacryloxypropyltris (trimethylsiloxy) silane and 1,1'-azobis (cyclohexane- A solution obtained by dissolving 1 part by weight of 1-carbonitrile in 100 parts by weight of methyl ethyl ketone was dropped into a reaction vessel over 2 hours and aged for 5 hours.

To the obtained resin, isophorone diisocyanate / trimethylolpropane adduct (IPDI / TMP system: NCO% = 6.1%) was added as a crosslinking agent to O.
After adjusting the H / NCO molar ratio to be 1/1, it was diluted with methyl ethyl ketone to prepare a coat resin solution having a solid ratio of 3% by weight.

Fired ferrite powder F-300 as core material
(Average particle size: 50 μm, manufactured by Powder-Tech Co.)
The amount of the coating resin with respect to the core material was 1.
Spiracoater (manufactured by Okada Seiko Co., Ltd.) so that the content becomes 5% by weight.
And dried. The obtained carrier was calcined at 160 ° C. for 1 hour in a hot-air circulation oven. After cooling, the ferrite powder bulk is opened to 106 μm and 75 μm.
Was crushed by using a screen shaker equipped with a screen mesh, to obtain a resin-coated carrier.

(Aggregation noise (white spots)) Each toner was mixed with the carrier obtained in the above production example at a toner mixing ratio of 7% by weight.
To prepare a developer. This developer was used under a N / N environment (25 ° C., 50%) using a digital full-color copying machine CF900 (manufactured by Minolta).
/ W15% images were printed on 5000 sheets. After printing, three full-size solid images (ID = 1.2) are printed on A3 paper.
Evaluation was performed according to the following criteria, and the average value of the three sheets was used as the evaluation result. The evaluation criterion is x when the image unevenness (white spot) having an ID of 1/2 or less of the solid image ID of 2 mm ² or more in the solid image occurs, and the white spot does not occur. Are observed in the image where nuclei of aggregates of about 0.3 μm are observed and the surrounding image density is slightly reduced at three or more places in the image. Those that did not occur at all were marked with ◎. Table 3 shows the results.

(Environmental stability) The developer prepared in the same manner as above was used under CF / L900 under L / L environment (1
(0 ° C., 15%), an image of B / W 15% was formed. The image density (ID) of the obtained image is determined by a Macbeth reflection densitometer R
Measured by D-900, the image density is 1.2 or more,
1.0 or more and less than 1.2 were evaluated as Δ, and less than 1.0 was evaluated as x.

Using a CF900, 5,000 images of 15% B / W were formed in an H / H environment (30 ° C., 85%). The white part of the obtained image was evaluated by visual observation, and the result was evaluated as follows: ○: no fogging occurred in the image; Δ: slight fogging but no practical problem; Is indicated by x. Table 3 shows the results.

(Fixing of Toner Component on Photoconductor (BS))
For the developer adjusted in the same manner as above, CF900
5,000 images of B / W 15% under N / N environment using
Printed. Evaluation was performed by visual observation on the photoreceptor at the beginning and after printing and evaluation by electron microscope observation, and evaluation by visual observation of a solid image at the beginning and after printing was performed. The external additives were not fixed on the photoreceptor by electron microscope observation. ◎ The external additives were fixed on the photoreceptor by electron microscope observation, but the external additive was fixed by visual observation. O: No image noise was observed and no image noise was generated. O: External additives and toner components were fixed on the photoreceptor by visual observation. When the external additive and toner component were fixed on the top, and this was recognized as noise on the image, it was evaluated as x. Table 3 shows the results.

(Heat resistance storage stability) When 5 g of the toner was put in a glass bottle and stored at 50 ° C. for 24 hours, x indicates that the toner agglomerated. Those that could not be seen were marked with ○. Table 3 shows the results.

[0054]

[Table 3]

[0055]

The toner of the present invention is excellent in environmental stability, fluidity, heat-resistant storage stability, does not cause toner components to adhere to the photoreceptor even after repeated use, and has no white spots in a solid image. Images can be obtained.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroyuki Fukuda 2-3-113 Azuchicho, Chuo-ku, Osaka-shi Osaka International Building Minolta Co., Ltd.

Claims (5)

[Claims] 1. A colored resin particle containing at least a coloring agent and a binder resin, having a number average particle size of 10 to 10.
Hydrophobic silica fine particles having a hydrophobicity of 50 or more at 50 nm, hydrophobic titania fine particles having a number average particle diameter of 10 to 90 nm and a hydrophobicity of 50 or more, and a number average particle diameter of 100 to
3000 nm of inorganic fine particles are added and mixed, the total amount of the silica fine particles and the titania fine particles is 1 to 3% by weight based on the colored resin particles, and the added amount of the inorganic fine particles is the colored resin particles. 0.1 to 3% by weight of the toner for developing an electrostatic latent image. 2. The method according to claim 1, wherein the weight ratio of the silica fine particles to the titania fine particles is 1: 9 to 9: 1.
The toner for developing an electrostatic latent image according to the above. 3. The silica fine particles having a number average particle size of 10
~ 30 nm, the number average particle size of the titania particles is 30 ~
90 nm, the number average particle diameter of the inorganic fine particles is 100 to 2
2. The toner for developing an electrostatic latent image according to claim 1, wherein the toner has a thickness of 000 nm. 4. The method according to claim 1, wherein the titania fine particles have a number average particle size of 10%.
2. The electrostatic latent image developing toner according to claim 1, comprising fine particles having a diameter of 30 to 30 nm and fine particles having a large diameter of 30 to 90 nm, wherein the large diameter fine particles are at least 10 nm larger than the small diameter fine particles. 5. The toner according to claim 1, wherein the toner is a toner used in a full-color image forming apparatus that reproduces a multicolor image using magenta, cyan, yellow, and black toners. An electrostatic latent image developing toner.