JP3115450B2 - Non-magnetic one-component toner and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder toner used for visualizing a latent image formed on an optical semiconductor in electrophotography, electrostatic recording, and the like. The present invention relates to a toner suitable for a non-magnetic one-component developing method, which is conveniently used for a paper fax or the like.

[0002]

2. Description of the Related Art In electrophotography, electrostatic recording, and the like, as a method of visualizing an electrostatic latent image formed on an optical semiconductor with a powder toner, a toner which is a colored fine powder and a toner are charged. Conventionally, a two-component magnetic brush developing method using a two-component developer with a carrier used for conveying a toner to an electrostatic latent image portion by a magnetic force has been most conveniently used. However, since the two-component magnetic brush developing method uses a magnetic force to transport the developer, a magnet is required in the developing roll, and the carrier is also a metal or an oxide thereof, such as iron powder, nickel powder, and ferrite. The container and the developer become heavy, which hinders reduction in size and weight of the recording apparatus.

On the other hand, for example, US Pat. No. 3,909,258
No. 4,121,931, the magnetic one-component developing method of enclosing a magnetic material inside the toner without using a carrier and conveying the toner to the electrostatic latent image portion by the magnetic force of the toner is also better than before. Has been used. However,
This developing method also requires a magnet inside the developing roll, and is disadvantageous from the viewpoint of reducing the weight of the developing device.

In order to solve the above-mentioned problems of these developing methods, there are described in US Pat. Nos. 2,895,847, 3,152,012, JP-B Nos. 41-9475, 45-2877, 54-3624 and the like. In recent years, studies and improvements of a non-magnetic one-component developing method using only a toner containing no magnetic powder have been actively conducted. However, in the non-magnetic one-component developing method,
Since the toner can be charged only at the moment of passing through the charging blade, it is very difficult to control the charging of the toner used in the present developing method. In order to solve such a problem, as disclosed in JP-A-59-231549, silica fine powder having been subjected to a special surface treatment is added to the toner surface, and is proposed in JP-A-63-226666. As described above, a special charge control agent is used. On the other hand, it is also important to improve the contact efficiency between the toner and the charging blade, and various external additives have been studied as disclosed in JP-A-64-77075 and JP-A-3-294864. Also,
For the purpose of preventing the toner having a large particle size from impairing the charging of a toner having a small particle size, the particle size distribution as disclosed in JP-A-63-279261 has been studied.

[0005] However, when the above method is used to repeatedly provide a toner which can provide a good image at the beginning, the image density is reduced, the fog is increased, and the resolution of the image is reduced when toner supply is repeated. There's a problem.
JP-A-3-294864 discloses that an inorganic fine powder having a particle size of 0.1 to 1.0 μm is added.The inorganic fine powder is added for polishing, and the purpose of the present invention is not to be considered. It is completely different.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a toner excellent in developability and stability over time with respect to a non-magnetic one-component developing method. An object of the present invention is to stably provide a high-quality copy image having an appropriate image density without background fog.

[0007]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have analyzed a conventional non-magnetic one-component toner. Observation of the surface of the toner with a scanning electron microscope revealed that inorganic fine particles that could be observed on an unused toner surface were not observed any more.
Further, when the inorganic element analysis of the toner surface was further performed, it was found that the toner after use had almost the same amount of inorganic oxide as the toner before use. From the above results, the inventor of the present invention concluded that the cause of image quality deterioration due to repeated printing is that as the printing proceeds, the inorganic fine particles present on the toner surface are embedded in the toner by being rubbed by a charging blade or the like, and the fluidity of the toner is reduced. Was determined to be worse. As a result of earnest studies based on such facts, they have found that the above-mentioned problems can be solved by attaching inorganic fine particles having a specific particle size range to the toner surface, and completed the present invention.

That is, according to the present invention, the average particle diameter is 30 nm on the surface of the colored particles containing the binder resin, the coloring agent, and the charge controlling agent.
As described above, an object of the present invention is to provide a non-magnetic one-component toner obtained by adhering inorganic fine particles of less than 100 nm, and a method for producing the same. Such a non-magnetic one-component toner of the present invention is suitably used for a developing device having a developing roll and a blade that uniformly regulates the thickness of a toner layer formed on the developing roll and gives a charge to the toner. Is done.

Although the particle size of the inorganic fine particles used in the present invention can be measured by a particle size distribution measuring device utilizing dynamic light scattering, it is difficult to dissociate the secondary aggregation of the particles. It is best to determine the particle size from a photograph obtained by a scanning electron microscope. As another index, an inorganic fine particle having a BET specific surface area of 20 to 80 m ² / g corresponds to the above particle diameter.

In the present invention, when the average particle diameter of the inorganic fine particles is smaller than 30 nm, the inorganic fine particles are easily embedded on the toner surface, and a non-magnetic one-component toner having satisfactory image stability over time cannot be obtained. In addition, when particles having an average particle diameter of 100 nm or more are adhered to the toner, appropriate fluidity cannot be imparted to the toner, so that satisfactory image density and image quality cannot be obtained. Easy to desorb,
It is easy to damage the photoreceptor and damage the charging blade. The particularly preferred average particle diameter of the inorganic fine particles is 70 nm or less.

As the composition of the inorganic fine particles used in the present invention, conventionally known ones such as silica, alumina, titania and zirconia can be used. It is preferable that the surface of these inorganic fine particles is made hydrophobic with a silane coupling agent, silicone oil, or the like from the viewpoint of environmental stability of toner charging.

The amount of the inorganic fine particles added to the toner of the present invention is preferably 0.1 to 5% by weight based on the colored particles containing the binder resin, the colorant and the charge control agent. The amount of the inorganic fine particles to be added must be carefully adjusted in consideration of the particle diameter of the inorganic fine particles, and further, in consideration of the material of the charging blade, the pressing pressure thereof, the material of the developing roll, and the like. Further, the mixing ratio of the binder resin, the colorant and the charge control agent in the colored particles of the toner of the present invention is 99 to 75% by weight of the binder resin and 0.5% of the colorant.
-20% by weight and the charge control agent 0.1-5% by weight are preferred. In the present invention, as a method for attaching the inorganic fine particles to the surface of the colored particles, any conventionally known powder mixing method can be used. Further, in the present invention, after the inorganic fine particles are adhered to the surface of the colored particles, the aggregates of the inorganic fine particles are separated and removed in a gas stream by a cyclone or the like, whereby a toner having more excellent temporal stability can be provided. Here, the aggregate of the inorganic fine particles refers to free inorganic fine particles remaining without being attached to the surface of the colored particles when the inorganic fine particles are attached to the surface of the colored particles. Since the aggregate of such inorganic fine particles easily changes its form, it is difficult to remove it with a vibrating sieve conventionally used for removing foreign matter in toner,
An airflow type separation / removal method such as a cyclone is required.

As the composition of the toner used in the present invention, conventionally known materials can be used. Examples of the binder resin of the toner used in the present invention include a charging blade and the like.
From the viewpoint of the toughness against applied stress, (a) the following general formula (I)

[0014]

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(Wherein R ¹ is an alkylene group having 2 to 4 carbon atoms, x and y are positive integers, and the average of the sum is 2 to 16). , (B) the following general formula (II) or (III)

[0016]

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Wherein R ² and R ³ each have 4 to 20 carbon atoms
Is a saturated or unsaturated hydrocarbon group. 1) to 50 mol% of the divalent carboxylic acid or its anhydride, and 10 to 10 mol% of trimellitic acid or its anhydride.
A polyester resin obtained by condensation polymerization of an acid component containing 30 mol% , especially a polyether having a glass transition temperature of 70 ° C or higher.
Effect of the present invention when using ester resin Ru is well exhibited. In the present invention, the glass transition temperature of the resin is:
It is determined according to a standard method using the DSC method.

Examples of the alcohol component of the polyester resin used in the present invention include polyoxypropylene (2.2) -2,2-bis (4-) represented by the aforementioned general formula (I).
(Hydroxyphenyl) propane, polyoxyethylene (2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (6) -2,2-bis (4
- hydroxyphenyl) propane, polyoxypropylene (16) -2,2-bis (4-hydroxyphenyl) Bisphenol A-based monomers such as propane can be cited
You.

The acid component used in the present invention includes n-dodecenyl succinic acid, iso-dodecyl succinic acid, iso-octyl succinic acid and n-dodecenyl succinic acid represented by the general formula (II) or (III). In addition to succinic acid derivatives such as octyl succinic acid and n-butyl succinic acid, phthalic acid, isophthalic acid, terephthalic acid, fumaric acid, maleic acid, trimellitic acid, pyromellitic acid, etc., and their anhydrides and lowers thereof Compounds used in the production of ordinary polyester resins such as alkyl esters can be used.

The polyester resin used in the present invention comprises:
Usually, it can be produced by polycondensing a polyol component and a polycarboxylic acid component at a temperature of 180 to 250 ° C. in an inert gas atmosphere. At this time, in order to accelerate the reaction, a commonly used esterification catalyst such as zinc oxide, stannous oxide, dibutyltin oxide, dibutyltin dilaurate and the like can be used.

The colorant used in the present invention includes carbon black; CI Pigment Yellow 1,
Acazoacetic acid arylamide monoazo yellow pigments such as those described in 3, 3, 74, 97 and 98; CI Pigment Yellow 12,
Acetoacetic acid arylamide disazo yellow pigments such as 13, 14, and 17; CI Solvent Yellow 19, 77, and 7
9, yellow dyes such as CI Disperse Yellow 164;
I. Pigment Red 48, 49: 1, 53: 1, 57,
57: 1, 81, 122, 5 etc. red or red pigments; CI Solvent Red 49, 52, 58, 8 etc. red dyes; CI Pigment Blue 15: 3 etc. copper Blue dyes and pigments of phthalocyanine and its derivatives; CI Pigment Green 7, 36 (phthalocyanine green)
And other green pigments. These dyes and pigments
They may be used alone or as a mixture of two or more.

Further, as the charge control agent used in the present invention, for negatively charged toner, chromium azo complex dye, iron azo complex dye, cobalt azo complex dye, chromium zinc zinc aluminum of salicylic acid or a derivative thereof is used. Boron complex or salt compound, chromium / zinc / aluminum of naphthol acid or its derivative, boron complex or salt compound, chromium / zinc / aluminum / boron complex or salt compound of benzylic acid or its derivative, long-chain alkyl. Carboxylates, surfactants such as long-chain alkyl sulfonates, for positively charged toner, nigrosine dyes and derivatives thereof, triphenylmethane derivatives, quaternary ammonium salts, quaternary phosphonium salts,
Derivatives such as quaternary pyridinium salts, guanidine salts, amidine salts and the like can be exemplified.

In the toner of the present invention, a magnetic substance such as ferrite, a conductivity modifier, a metal oxide such as tin oxide, silica, alumina, zirconia, titania, and zinc oxide;
An extender, a reinforcing filler such as a fibrous substance, an antioxidant, a release agent, and the like may be added as necessary.

Further, in addition to the inorganic fine particles having a specific particle size range specified in the present invention, the toner
Other additives may be used in combination to prevent filming or to improve the cleaning performance of the residual toner on the photoconductor. These additives include silica, alumina,
Inorganic oxides such as titania, zirconia, tin oxide, zinc oxide, acrylates, methacrylates,
Examples thereof include homo- or copolymer resin fine particles such as styrene, fluoro resin fine particles, silicone resin fine particles, higher fatty acids such as stearic acid and metal salts thereof, carbon black, graphite fluoride, silicon carbide, and boron nitride. There is no problem even if these particles are out of the particle size range of the inorganic fine particles shown in the present invention. As a method for producing the toner of the present invention, conventionally known production methods such as a kneading and pulverizing method, a spray drying method, and a polymerization method can be used.

[0025]

[Function / Effect] Since the particle diameter of the inorganic fine particles used in the present invention is specified in an appropriate range, it is possible to impart proper powder fluidity to the toner, and the toner is applied by a pressure applied from a charging blade or the like. It is rarely embedded inside. Therefore, by using the toner of the present invention, it is possible to provide a non-magnetic one-component developing system in which the image density and the image quality are less changed by continuous copying. Further, in the present invention, a polyester resin having a glass transition temperature of 70 ° C. or higher, which is less likely to be deformed by pressure due to a charging blade or the like, particularly a polyester resin containing a bisphenol A-based monomer and an alkenyl succinic acid-based monomer component as components is used. By doing so, the effect of the present invention becomes more remarkable.

[0026]

EXAMPLES Examples of the present invention will be described below, but the present invention is of course not limited to these examples. In the examples, what is indicated as “parts” indicates “parts by weight” unless otherwise specified.

Production Example 1 540 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 215 g of polyoxyethylene (2) -2,2-bis (4-hydroxyphenyl) propane, terephthalic acid 225 g and n-dodecenyl succinic anhydride (31.5 g) were placed in a glass 1-liter four-necked flask, fitted with a thermometer, a stainless steel stirring rod, a falling condenser and a nitrogen inlet tube, and heated to 230 ° C. in an electric heating mantle. The reaction was carried out while stirring under a nitrogen stream. When the water generated by the reaction stopped flowing out, the acid value was measured to be 1.5. Further, 94 g of trimellitic anhydride was added and reacted for about 8 hours.
When the reaction became, the reaction was terminated. The obtained resin is a pale yellow solid, having an acid value of 25 mgKOH / g and a hydroxyl value of 26 mgKOH / g.
g, glass transition point = 74 ° C, weight average molecular weight = 180,000.

Example 1 Resin of Production Example 1 100 parts Carbon black 4 parts Chromium / azo complex 1.5 parts Low molecular weight polypropylene / wax 2 parts The above compositions were premixed, kneaded with a pressure kneader, crushed and classified and weight averaged. Colored particles having a particle size of 10 μm were obtained. 0.8 parts of silica R809 (average particle size = 40 nm) manufactured by Nippon Aerosil Co., Ltd. was mixed with 100 parts of the colored particles using a Henschel mixer to obtain a toner.

Example 2 Hydrophobic silica MOX-80 (particle size = 30 nm) manufactured by Nippon Aerosil Co., Ltd. was treated with hexamethyldisilazane to prepare hydrophobic silica A having a methanol hydrophobicity of 38%. To 100 parts of the same colored particles as in Example 1, 0.6 part of hydrophobic silica A was similarly mixed to obtain a toner.

Example 3 Alumina manufactured by Daimei Chemical Co., Ltd. (particle size = 60 nm) was hydrophobized with hexamethyldisilazane to prepare hydrophobic alumina B having a methanol hydrophobicity of 21%. The same colored particles as in Example 1
In 100 parts, 1.2 parts of hydrophobic alumina B were similarly mixed to obtain a toner.

Comparative Example 1 A toner was prepared by similarly mixing 0.3 part of hydrophobic silica R972 (particle size = 16 nm) manufactured by Nippon Aerosil Co., Ltd. with 100 parts of the same colored particles as in Example 1.

Comparative Example 2 Alumina manufactured by Daimei Chemical Co., Ltd. (particle size = 100 nm) was hydrophobized with hexamethyldisilazane to prepare hydrophobic alumina C having a methanol hydrophobicity of 38%. The same colored particles as in Example 1
In 100 parts, 2 parts of hydrophobic alumina C were similarly mixed to obtain a toner.

Test Example A continuous print test of 2,000 sheets was performed on the toners of Examples 1 to 3 and Comparative Examples 1 and 2 using a modified facsimile TF-58HW machine manufactured by Toshiba. A measurement of the apparent density of loose toner fluidity was performed. Table 1 shows the results.

[0034]

[Table 1]

Note) 1) Measure with Macbeth densitometer 2) Copy the image on the photoreceptor onto a mending tape and measure the Y value with a colorimeter CR-221 (manufactured by Minolta Camera Co., Ltd.). And the difference from the Y value of the tape.

As shown in Table 1, the toner of the present invention was 2,0
Even when continuous printing of 00 sheets was performed, the loose apparent density of the toner did not decrease and a good image was stably provided. On the other hand, when the toner of Comparative Example 1 to which silica having a small particle diameter was added was used, , The apparent density decreased, the image density decreased, and the uniformity of solid black deteriorated. In addition, when the toner of Comparative Example 2 to which inorganic particles having a large particle diameter were added was used, it was found that scratches occurred on the photoreceptor, and the inorganic particles were accumulated in the scratches. Observation of the toner surface of Example 1 and the toner surface of Comparative Example 1 after printing 2,000 sheets with a scanning electron microscope confirmed that silica was present on the toner surface of Example 1; The silica was hardly observed on the surface of the toner No. 1.

Example 4 The toner of Example 1 was subjected to cyclone classification using an MDS classifier manufactured by Nippon Pneumatic Co., Ltd., from which the classification part was removed, to remove aggregates of inorganic fine particles. A continuous printing test was performed on the obtained toner using a modified Toshiba plain paper facsimile TF-58HW while supplying toner.
Good image quality without image defects could be maintained up to 5,000 sheets.
The photoreceptor was removed from the device after the test, and the surface was observed. No problems such as scratches were found.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-215964 (JP, A) JP-A-57-109825 (JP, A) JP-A-6-95429 (JP, A) JP-A 60-215 112052 (JP, A) JP-A-2-190866 (JP, A)

Claims (4)

(57) [Claims] (1 ) The following general formula (I) : (Wherein, R ¹ is an alkylene group having 2 to 4 carbon atoms,
x and y are positive integers, and the average of the sum is 2 to 16
is there. A) a diol component represented by the following general formula (II) or (III) : (Wherein R ² and R ³ are each saturated or substituted with 4 to 20 carbon atoms)
Is an unsaturated hydrocarbon group. Divalent carbo represented by)
Acid or its anhydride in 1 to 50 mol%,
Contains 10 to 30 mol% of melitic acid or its anhydride
Polyester obtained by condensation polymerization of acid components
A non-magnetic one-component toner comprising an inorganic fine particle having an average particle diameter of 30 nm or more and less than 100 nm attached to the surface of a colored particle containing a binder resin composed of a fat , a colorant, and a charge control agent. 2. An inorganic fine particle having an average particle size of 30 nm or more and 70 nm or more.
2. The non-developing device according to claim 1, which is used for a developing device having a developing roll and a blade that uniformly regulates the thickness of a toner layer formed on the developing roll and gives a charge to the toner. Magnetic one-component toner. 3. The non-magnetic one-component toner according to claim 1, wherein the binder resin used for the colored particles is a polyester resin having a glass transition temperature of 70 ° C. or higher. 4. An inorganic fine particle having an average particle diameter of 30 nm or more and less than 100 nm is adhered to the surface of a colored particle containing a binder resin, a colorant, and a charge controlling agent, and then an aggregate of the inorganic fine particle is introduced into a gas stream. 2. The method according to claim 1, wherein the toner is separated and removed.