JPH11184139A - Nonmagnetic one component developer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the nonmagnetic one component developer small in change of the surface state of a toner even in repeating copying and capable of retaining toner characteristics and prevented from production of powdery dust and power smoke out of a developing device and excellent in durability. SOLUTION: This nonmagnetic one component developer comprises negatively chargeable toner particles containing a binder resin and a colorant and fine inorganic particles having a primary average particle diameter of 1-70 nm and surface-treated with a hydrophobe, and a little larger inorganic fine particles having a primary average particle diameter of 100-500 nm and surface-treated with a surface treating agent having a cationic group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developer for developing an electric latent image in electrophotography and electrostatic printing, and more particularly to a non-magnetic one-component developer.

[0002]

2. Description of the Related Art In general, a two-component developing system and a one-component developing system are known as a developing device, but a one-component developing system is often adopted from the viewpoint of preventing a reduction in charging performance and miniaturizing an image forming apparatus. Have been.

The one-component developing system includes a magnetic one-component system and a non-magnetic one-component system. In the magnetic one-component developing system, it is usually necessary to add black magnetic powder to the toner. In this case, a non-magnetic one-component developing system is preferable. In the non-magnetic one-component developing method, the developer regulating member is arranged to be in contact with the developer carrier, and the non-magnetic one-component developer passes through the gap between the developer carrier and the developer regulating member. By forming a thin toner layer on the carrier by carrying out the charging, the toner is transferred to the developing area as it is,
The electrostatic latent image formed on the electrostatic latent image carrier is developed.

In general, inorganic particles such as silica and titania are added (externally added) to a toner as a fluidizing agent in order to improve fluidity. For example, JP-A-7-439
No. 30, there is reported a technique in which a fluidizing agent having a particle size of 0.05 μm (50 nm) or less is externally added to toner particles in a one-component developing system. However, in the one-component developing method, as described above, the toner particles are charged by passing through the gap (regulating portion) between the developer carrying member and the developer regulating member, so that a large stress is applied to the toner at that time. For this reason, the fluidizing agent externally added to the toner is embedded in the toner particles, so that the fluidity cannot be secured for repeated use. Further, there is a problem that the surface condition of the toner changes due to the embedding of the fluidizing agent on the toner surface due to repeated use, and it is difficult to maintain stable toner characteristics.

[0005] On the other hand, a technique of externally adding inorganic fine particles having a relatively large particle diameter, which hardly embeds in the toner particles, is also known. There is a problem that the detached inorganic fine particles stay or agglomerate, causing streaks or unevenness in the thin toner layer. Apart from this, there is also a problem that toner particles that need to be set to have high fluidity, such as color toner, spill out of the developing device as powder smoke.

[0006]

According to the present invention, even when copying is repeated, the change in the surface condition of the toner is small, and the toner characteristics can be maintained. An object of the present invention is to provide a non-magnetic one-component developer excellent in durability, which does not generate smoke outside the container.

[0007]

SUMMARY OF THE INVENTION The present invention is directed to negatively charged toner particles containing at least a binder resin and a colorant, inorganic fine particles having an average primary particle size of 1 to 70 nm, and an average primary particle size of 100 nm to 500 nm. A non-magnetic one-component developer comprising large-sized inorganic fine particles, wherein the small-sized inorganic fine particles are surface-treated by a hydrophobizing agent, and the large-sized inorganic fine particles have a cationic group-containing surface treatment. The present invention relates to a non-magnetic one-component developer characterized by being surface-treated with an agent.

In the present specification, the average primary particle size of the inorganic fine particles is determined by a scanning electron microscope (JSM-840A; manufactured by JEOL Ltd.).
And the average of the major axis of the fine particles was shown.

In the present invention, a small amount of inorganic fine particles and a large amount of inorganic fine particles having a specific particle size are externally added to a conventional toner particle by a specific amount, so that a toner thin layer can be formed by repeated copying. No streak or unevenness occurs on the
It is considered that a non-magnetic one-component developer having excellent durability can be provided. It is thought that the fluidity is reduced due to the small particle size inorganic fine particles directly contributing to the improvement of the fluidity, which are embedded in the toner particles by repeated copying. By including a specific amount of inorganic fine particles having a small diameter, the probability of contact between toner particles is reduced, and external stress such as regulation by a developer regulating member during development or stirring in a developing device is diffused. It is considered that the surface is less likely to be directly affected by external stress and the surface state is less likely to change, and as a result, the embedding of the inorganic fine particles having a small particle diameter is eased and the durability of the developer is improved.

In the present invention, since the inorganic fine particles having a specific particle size are contained and the fine particles are surface-treated with a surface treating agent having a cationic group, the fine particles are negatively charged. It is considered that the electrostatic attraction with the particles avoids the detachment of the large-sized inorganic fine particles which adhere to the toner particles and are generally easily detached.
Furthermore, since the detachment of the large-diameter inorganic fine particles hardly occurs, the electrostatic attractive force acts by interposing the large-diameter inorganic fine particles between the toner particles. It is considered that the generation of powder smoke outside the developing device is avoided.

The inorganic fine particles having a small particle diameter contained in the developer of the present invention have an average primary particle diameter of 1 to 70 nm, preferably 5 to 60 nm.
nm inorganic fine particles. By uniformly covering the toner particles by incorporating the fine particles, uniform desired toner fluidity can be obtained. If the average primary particle size is less than 1 nm, the stability of charging of the toner after long-term use and the stability of charging of the toner with respect to environmental changes become insufficient.
If the ratio exceeds the above range, the dispersibility of the inorganic fine particles in the toner particles is remarkably reduced, so that the fluidity and chargeability of the toner become non-uniform, and a good copied image cannot be obtained.

As the material used for the small-sized inorganic fine particles, various materials conventionally used as a fluidizing agent can be used, for example, silica, alumina, titania (titanium dioxide), tin oxide, and the like. , Magnesium oxide,
Zinc oxide or the like can be used alone or in combination of two or more. Preferred small-particle inorganic fine particles are silica and titania.

In the present invention, the inorganic fine particles having a small particle diameter are surface-treated with a hydrophobizing agent. This is because the environmental stability of the toner, in particular, the change in toner charge due to the influence of humidity is suppressed. The degree of hydrophobicity is 30 to 80%, preferably 4
Desirably, it is 0 to 80%. If the degree of hydrophobicity is lower than 30%, the environmental resistance is liable to deteriorate, and if it exceeds 80%, it is difficult to obtain a stable product in production.

As the hydrophobizing agent, a silane coupling agent, a titanate coupling agent, a silicone oil,
Conventionally used hydrophobizing agents such as silicone varnish can be used, preferably a silane coupling agent,
A silicon-based oil, more preferably, a silane-based coupling agent is used. Examples of the silane coupling agent include trimethylsilane, trimethylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, benzyldimethylchlorosilane,
Methyltrimethoxysilane, methyltriethoxysilane, isobutyltrimethoxysilane, n-hexyltrimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, trimethylmethoxysilane, hydroxypropyltrimethoxysilane, phenyltrimethoxysilane, n-hexadecyl Trimethoxysilane, n-
Octyltrimethoxysilane, n-octadecyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane and the like can be used.

As the silicone oil, for example, dimethylpolysiloxane, methylhydrogenpolysiloxane, methylphenylpolysiloxane and the like can be used. The hydrophobizing agent may be used in an amount sufficient to achieve the above-mentioned degree of hydrophobization, and may be treated by a conventional method.

In the present invention, the inorganic fine particles having a small particle diameter, in particular, the inorganic fine particles having a small particle diameter made of titania, may be subjected to a surface treatment using a fluorine-based silane coupling agent or a fluorine-based silicon oil in combination. This is because the toner is negatively charged, thereby improving the negatively chargeable toner,
This is because it is effective for preventing image fog. Normally, the chargeability of the toner is controlled by including a charge control agent in the toner particles. However, in the one-component developing system according to the present invention, the developer carrier and the developer regulating member Since the toner is charged by frictional charging when the toner passes through the gap between the press contact portions, the chargeability of the toner particles is important for the chargeability of the toner particles. Therefore, when controlling the chargeability, it is more effective to adjust the chargeability of the external additive of the toner than to adjust the content of the charge control agent.

As the fluorine-based silane coupling agent,
For example, the following compounds can be used alone or as a mixture, but are not limited thereto. _{· CF 3 (CH 2) 2} SiCl 3 · CF 3 (CF 2) 5 SiCl 3 · CF 3 (CF 2) 5 (CH 2) 2 SiCl 3 · CF 3 (CF 2) 7 (CH 2) 2 SiCl 3 CF ₃ (CF ₂ ) ₇ CH ₂ CH ₂ Si (OCH ₃ ) ₃ CF ₃ (CF ₂ ) ₇ (CH ₂ ) ₂ Si (CH ₃ ) Cl ₂ CF ₃ (CH ₂ ) ₂ Si (OCH _{3 ) 3 · CF 3 (CH 2} ) 2 Si (CH 3) (OCH 3) 2 · CF 3 (CF 2) 3 (CH 2) 2 Si (OCH 3) 3 · CF 3 (CF 2) 5 (CH 2 ) ₂ Si (OCH ₃ ) ₃ · CF ₃ (CF ₂ ) ₆ CONH (CH ₂ ) ₂ Si (OC ₂ H ₅ ) ₃ · CF ₃ (CF ₂ ) ₆ COO (CH ₂ ) ₂ Si (OCH ₃ ) ₃・ CF ₃ (CF ₂ ) ₇ (CH ₂ ) ₂ Si (OCH ₃ ) ₃・ CF ₃ (CF ₂ ) ₇ (CH ₂ ) ₂ Si (CH ₃ ) (OCH ₃ ) ₂・ CF ₃ (CF ₂ ) ₇ NH (CH ₂ ) ₃ Si (OC ₂ H ₅ ) ₃ .CF ₃ (CF ₂ ) ₈ (CH ₂ ) ₂ Si (OCH ₃ ) ₃

The fluorine-based silane coupling agent is used in an amount of 1 to 20 parts by weight, preferably 2 to 100 parts by weight of the inorganic fine particles.
It is preferable to use １５15 parts by weight.

In order to surface-treat inorganic fine particles using the above-mentioned surface treating agent (fluorine-based coupling agent or fluorine-based silicone oil, hydrophobizing agent), for example, the surface-treating agent is diluted with a solvent, After adding and mixing the liquid, heating and drying the mixture, crushing is performed by a dry method. The inorganic fine particles are dispersed in an aqueous system to form a slurry, and then a surface treating agent is added and mixed, and the mixture is heated and dried. After that, it can be carried out by a wet method of crushing or the like. In particular, after performing the hydrophobic treatment in an aqueous system from the viewpoint of the uniformity of the surface treatment of the hydrophobic agent with respect to the inorganic fine particles, the anti-aggregation property of the inorganic fine particles, and the like, the fluorinated coupling agent or the fluoric silicone oil is used by a dry method. Surface treatment is preferred.

The inorganic fine particles having a small particle diameter which has been subjected to the surface treatment in the above manner are contained in an amount of 0.3 to 3.0% by weight based on the toner particles.
Preferably 0.5-2.5% by weight, more preferably 1.
Desirably, the content is 0 to 2.5% by weight. If the amount is less than 0.3% by weight, the desired fluidity cannot be imparted, the durability deteriorates, and white streaks and image unevenness tend to occur in the copied image. On the other hand, if the content is more than 3.0% by weight, contamination in the apparatus occurs, the amount of poorly charged toner increases, fogging occurs in a copied image, and the cost is disadvantageous.

In the present invention, a mixture of two or more kinds of inorganic fine particles having different average primary particle diameters within the above range may be used as the small-diameter inorganic fine particles. Hereinafter, a case where the inorganic fine particles having a smaller particle diameter are referred to as first inorganic fine particles, the inorganic fine particles having a larger particle diameter are referred to as second inorganic fine particles, and these two types of inorganic fine particles are used as the above-described inorganic fine particles having a small particle diameter will be described.

In the present invention, when a mixture of the first inorganic fine particles and the second inorganic fine particles is used as the small inorganic fine particles, one of the inorganic fine particles is preferably made of silica, more preferably the other inorganic fine particles. The fine particles are composed of titania. By using two kinds of inorganic fine particles of silica and titania, environmental resistance and chargeability are improved, and these effects become remarkable especially when a full-color developer is prepared.

The first inorganic fine particles have an average primary particle size of 1 to 40.
nm, preferably 5 to 35 nm, more preferably 5 to 3 nm.
Desirably, it is 0 nm. By including inorganic fine particles having such a particle size, desired toner fluidity can be more easily obtained. When the average primary particle size is less than 1 nm, the stability of charging of the toner due to long-term use and the stability of charging of the toner against environmental changes become insufficient.
When the ratio exceeds, it is difficult to obtain the effect of improving the fluidity.

The second inorganic fine particles have an average primary particle size of 40 to 7
It is desirable that the average particle diameter of the first inorganic fine particles is 0 nm, preferably 40 to 60 nm, which is 10 nm or more.
The decrease in the fluidity of the toner due to repeated copying, which has conventionally been a problem, is thought to be due to the fact that small inorganic fine particles such as the first inorganic fine particles are embedded in the toner particles. , The embedding can be relaxed and desired fluidity can be secured. When the average primary particle diameter is less than 40 nm, the effect of relaxing the embedding of the first inorganic fine particles in the toner particles is liable to be remarkably reduced. When the average primary particle diameter exceeds 70 nm, the dispersibility of the inorganic fine particles in the toner particles is significantly reduced. The properties and charging properties become non-uniform, and good copied images cannot be obtained.

The contents of the first inorganic fine particles and the second inorganic fine particles are set so that the total content thereof becomes the above-mentioned content of the small inorganic fine particles. 0.1 to 2.0% by weight, preferably 0.3 to 1.5% by weight, and the second inorganic fine particles 0.1 to 2.5% by weight with respect to the toner particles.
Preferably, the content is 0.3 to 2.0% by weight. The content of the first inorganic fine particles is 0.1% by weight.
If the amount is less than the desired value, the desired fluidity is not easily provided, and white streaks are easily generated in the copied image. If the amount is more than 2.0% by weight, contamination in the apparatus occurs, and the amount of poorly charged toner increases, causing fog on the copied image. It is easy and disadvantageous in terms of cost. When the content of the second inorganic fine particles is less than 0.1% by weight, the effect of reducing the embedding of the first inorganic fine particles is difficult to be obtained, and when the content is more than 2.5% by weight, contamination in the machine or occurrence of poorly charged toner increases. As a result, fogging tends to occur in the copied image, and the cost tends to be disadvantageous.

The inorganic fine particles having a large particle diameter contained in the developer of the present invention have an average primary particle diameter of 100 to 500 nm, preferably 120 to 400 nm, more preferably 150 to 300 n.
m. As described above, since the average primary particle size of the large-sized inorganic fine particles is relatively large, the probability of contact between the toner particles is reduced, and external control such as regulation by the developer regulating member during development or stirring in the developing device is performed. Since the stress is diffused, the surface of the toner particles is less likely to be directly affected by external stress. In addition, the large-diameter inorganic fine particles have a function of enhancing the function of alleviating embedding of the small-diameter inorganic fine particles. Further, by the external addition of the fine particles, the photosensitive member is appropriately polished, and the effect as a cleaning improver can be expected. Particle size is 1
If the thickness is less than 00 nm, the above-mentioned effects cannot be expected, and the charging property is greatly affected. On the other hand, when the thickness exceeds 500 nm, the particles are easily detached from the toner particles, so that the particles easily accumulate in the regulating portion, resulting in a thin layer formation defect and a charging defect.

As the material used for the large-diameter inorganic fine particles, similarly to the small-diameter fine particles, various materials conventionally used as a fluidizing agent can be used. You may use it. Preferred large-diameter inorganic fine particles are titania, alumina, silica, barium titanate, zinc oxide, tin oxide, magnesium zirconate, strontium zirconate, calcium zirconate, and barium zirconate.

In the present invention, such large-diameter inorganic fine particles are surface-treated with a surface treating agent having a cationic group. For this reason, the large-diameter inorganic fine particles after the treatment are effectively subjected to electrostatic adhesion to the negatively-charged toner particles, and the separation of the fine particles from the toner particles is avoided,
The formation of a thin toner layer, which has conventionally been a problem, can be avoided, and a good copied image can be provided. In addition, by making it difficult for large-diameter inorganic fine particles to desorb,
The negatively chargeable toner particles are via the large-diameter inorganic fine particles,
Alternatively, since it is easily connected to the large-sized inorganic fine particles electrostatically, generation of powder smoke outside the developing device is also avoided.

As the surface treating agent having a cationic group, for example, aminosilane, silane containing an ammonium base, and amino-modified silicone oil can be used.

The aminosilane is a so-called aminofunctional silane, and the one represented by the following general formula can be used: X _m1 SiY _n1 (where X is an alkoxy group or a chlorine atom, and m ₁ is 1 to 1)
An integer of 3, Y is a hydrocarbon group having a primary to amino group,
n1 represents an integer of ₁ to 3).

Specifically,

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[0032]

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[0033]

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Specific examples of the ammonium group-containing silane include:

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[0035]

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Further, there may be mentioned those obtained by substituting the alkoxy group of the above-mentioned organosilane with another hydrolyzable group or hydroxyl group, and these may be used in combination of two or more.

As the amino-modified silicone oil, those represented by the following general formula can be used:

Embedded image (Where R ₁ represents a hydrogen, an alkyl group, an aryl group or an alkoxy group, R ₂ represents an alkylene group or a phenylene group, and R ₃ and R ₄ represent a hydrogen, an alkyl group or an aryl group. alkyl group, an aryl group, an alkylene group, a phenylene group may contain amine, and to the extent not impairing the chargeability may have a substituent such as halogen .m ₂ and n ₂ are positive Represents an integer.)

Specifically, the following are available on the market. Viscosity at 25 ° C. Amine equivalent Equivalent Trade name (cPs) SF8417 (manufactured by Toray Silicone Co., Ltd.) 1200 3500 KF393 (manufactured by Shin-Etsu Chemical Co., Ltd.) 60 360 KF857 (manufactured by Shin-Etsu Chemical Co., Ltd.) 70 830 KF860 (manufactured by Shin-Etsu Chemical Co., Ltd.) 250 7600 KF861 (manufactured by Shin-Etsu Chemical Co., Ltd.) 3500 2000 KF862 (Shin-Etsu Chemical Co., Ltd.) 750 1900 KF864 (Shin-Etsu Chemical Co., Ltd.) 1700 3800 KF865 (Shin-Etsu Chemical Co., Ltd.) 90 4400 KF369 (Shin-Etsu Chemical Co., Ltd.) 20 320 KF383 (Shin-Etsu Chemical Co., Ltd.) 20 320 X-22-3680 (Shin-Etsu Chemical Co., Ltd.) 90 8800 X-22-380D (Shin-Etsu Chemical Co., Ltd.) 2300 3800 X-22-3801C (Shin-Etsu Chemical Co., Ltd.) 3500 3800 X-22-3810B (Shin-Etsu Chemical Co., Ltd.) 1300 17 0 Note that the amine equivalent, equivalent weight per amine (g /
eqiv) is the value obtained by dividing the molecular weight by the number of amines per molecule.

The amount of the surface treating agent having a cationic group to be used is preferably 0.1 to 20 parts by weight, more preferably 0.5 to 15 parts by weight, based on 100 parts by weight of the inorganic fine particles.

In order to treat the inorganic fine particles with the surface treating agent having a cationic group as described above, such a surface treating agent is treated with tetrahydrofuran (THF), toluene, ethyl acetate, methyl ethyl ketone or acetone, ethanol, hydrogen chloride saturated. The mixture is diluted with a solvent such as ethanol, and the inorganic fine powder is forcibly stirred with a blender or the like, and a diluting solution of the surface treating agent is added dropwise or sprayed, and mixed well. At that time, a device such as a kneader coater, a spray drier, a thermal processor, and a fluidized bed can be used.

Next, the obtained mixture is transferred to a vat or the like, placed in an oven, and heated and dried. Then again the mixer,
Disintegrate sufficiently with a jet mill or the like. Further, it is desirable to classify as necessary, the volume average particle diameter (secondary aggregate particle diameter) by dry method of laser diffraction type is 10μm or less,
It is preferable that aggregated particles having a size of 30 μm or more be suppressed to 1% by volume or less.

In addition to the dry method, the inorganic fine powder is immersed in an organic solvent solution of the surface treating agent and dried, or the inorganic fine powder is dispersed in water to form a slurry, and then the surface treating agent is treated. There is also a wet processing method in which an aqueous solution is dropped, and then the inorganic fine powder is settled, heated, dried, and crushed. The temperature during heating is preferably 100 ° C. or higher.
When the temperature is lower than 100 ° C., the condensation reaction between the inorganic fine powder and the surface treating agent is difficult to complete.

The content of the large-diameter inorganic fine particles subjected to the surface treatment in this manner is 0.3 to the toner particles.
%, Preferably 0.4 to 2.0% by weight. If the amount is less than 0.3% by weight, the effect of the addition becomes insufficient. On the other hand, when the content exceeds 3.0% by weight, the large-diameter inorganic fine particles detached from the toner particles increase, so that the inorganic fine particles easily accumulate in the regulating portion and cause a thin layer formation defect.

The above-mentioned inorganic fine particles having a small particle diameter and inorganic fine particles having a large particle diameter are externally added to negatively charged toner particles obtained by a known method. The negatively charged toner particles used in the present invention contain at least a binder resin and a colorant.

As the binder resin used in the present invention, a resin capable of rendering the obtained toner particles negatively charged is used. In this case, a resin that can be controlled to be negatively charged by internally adding a charge control agent described later may be used. Further, in order to improve the dispersibility of the colorant in the binder resin, 1.0 to 30.0 KOH mg /
g, preferably a resin having an acid value of 1.0 to 25.0 KOH mg / g, more preferably 2.0 to 20.0 KOH mg / g. This has an acid value of 1.0 KOH
When the amount is smaller than mg / g, the effect of improving the dispersibility is reduced, and 3
This is because if the amount exceeds 0.0 KOH mg / g, the change in the charge amount due to environmental fluctuations increases.

The kind of the resin is not limited as long as it is such a binder resin. For example, a styrene resin, an acrylic resin, a styrene-acryl resin, a polyamide resin,
Polyester-based resins, polyurethane-based resins, epoxy-based resins and other known resins can be used alone or in combination, and a suitable resin may be appropriately selected and used according to the use. For example, a polyester resin is used when preparing a negatively chargeable toner without using a charge control agent, and a polyester resin or styrene-acryl is used when preparing a negatively chargeable toner using a negative charge control agent. It is preferable to use a polyester resin when preparing a full-color toner and a polyester resin or a styrene-acrylic resin when preparing a black toner.

In the present invention, a preferred polyester resin contains bisphenol A alkylene oxide adduct as an alcohol component as a main component, and phthalic dicarboxylic acids or a phthalic dicarboxylic acid and an aliphatic dicarboxylic acid as an acid component. It is synthesized by a polycondensation reaction.

As the bisphenol A alkylene oxide adduct, bisphenol A propylene oxide adduct and bisphenol A ethylene oxide adduct are suitable, and it is preferable to use a mixture of these.

As the alcohol component, the following diols or polyhydric alcohols may be slightly used together with the bisphenol A alkylene oxide adduct. Such alcohol components include, for example, ethylene glycol, diethylene glycol, triethylene glycol, 1,2
Diols such as propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, didiol Pentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, Trimethylolpropane, 1,3,
5-trihydroxymethylbenzene and the like.

The phthalic dicarboxylic acids include phthalic dicarboxylic acids such as terephthalic acid and isophthalic acid;
The acid anhydride or the lower alkyl ester thereof can be used.

The aliphatic dicarboxylic acids usable together with the phthalic dicarboxylic acids include aliphatic dicarboxylic acids such as fumaric acid, maleic acid, succinic acid, alkyl or alkenyl succinic acids having 4 to 18 carbon atoms, and acids thereof. Examples thereof include anhydrides and lower alkyl esters thereof.

In order to adjust the acid value of the resin, a small amount of a polycarboxylic acid such as trimellitic acid may be used as long as the light transmittance of the toner is not impaired. Examples of such a polyvalent carboxylic acid component include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 1,2,5-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid,
1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, 1,2 , 4-cyclohexanetricarboxylic acid, tetra (methylenecarboxyl) methane,
Examples thereof include 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid, anhydrides thereof, and lower alkyl esters.

When the negatively chargeable toner particles of the present invention are used as a full-color toner, the binder resin has a glass transition point of 55 to 75 ° C., preferably 58 to 7 ° C.
0 ° C, softening point 95-120 ° C, preferably 100-1
At 18 ° C., the number average molecular weight is 2500 to 6000, preferably 3000 to 5500, and the weight average molecular weight / number average molecular weight is 2 to 8, preferably 3 to 7. When the glass transition point is low, the heat resistance of the toner is reduced, and when the glass transition point is high, the light transmittance and the color mixing are reduced. When the softening point is low, a high-temperature offset is likely to occur during fixing, and when the softening point is high, the fixing strength is reduced. When the number average molecular weight is small, the toner is easily peeled off when the image is bent, and when the number average molecular weight is large, the fixing strength is reduced. When the weight-average molecular weight / number-average molecular weight is small, high-temperature offset is likely to occur, and when it is large, the light transmittance is reduced.

As the colorant, various known colorants such as cyan, magenta, yellow, and black can be used, and the amount of the colorant can be the same as that of the conventional colorant. Usually, the colorant is added in an amount of about 1 to 15 parts by weight based on 100 parts by weight of the binder resin.

The negatively charged toner particles of the present invention may contain, in addition to the above-mentioned colorants, desired additives such as a charge control agent and an anti-offset agent.

As the charge control agent, a zinc salicylate complex or the like and other known negative charge control agents can be used, and the type thereof may be selected according to the purpose of use. For full-color copying, it is preferable to use a colorless, white or pale yellow charge control agent. There is no particular limitation for black copy. The amount of the charge control agent may be appropriately set according to the purpose of use, but is usually 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. Used in the range.

The anti-offset agent is not particularly limited. For example, polyethylene wax, oxidized polyethylene wax, polypropylene wax,
Oxidized polypropylene wax, carnauba wax, sasol wax, rice wax, candelilla wax, jojoba oil wax, beeswax, and the like can be used. This not only improves the offset resistance, but also reduces the problem of toner sticking to the developer regulating member and the developer carrier in the non-magnetic one-component developing device. It is particularly preferable to use a wax having an acid value of 0.5 to 30 KOH mg / g from the viewpoint of dispersibility in a binder resin having the above acid value. The amount of the wax to be added is preferably 0.5 to 5 parts by weight, more preferably 1 to 4 parts by weight, based on 100 parts by weight of the binder resin. This is because if the amount is less than 0.5 part by weight, the effect of the addition is insufficient, and if it is more than 5 parts by weight, light transmittance and color reproducibility are reduced.

The toner particles according to the present invention are prepared by using the above-mentioned binder resin and colorant and other desired additives, and kneading and pulverizing, suspension polymerization, emulsion polymerization, emulsion dispersion granulation, and encapsulation. It can be produced by other known methods such as a method. Among these production methods, it is preferable to produce by a kneading / pulverization method from the viewpoint of production cost and production stability.

The kneading and pulverizing method includes a step of mixing toner components such as a resin and a colorant with a mixer such as a Henschel mixer, a step of melting and kneading the mixture, a step of cooling and kneading the kneaded material, Toner particles are produced by a step of finely pulverizing the coarsely pulverized particles and a step of classifying the obtained finely pulverized particles. The volume average particle diameter of the toner particles of the present invention is preferably adjusted to 4 to 10 μm, more preferably 6 to 9 μm, from the viewpoint of high definition reproducibility of an image. The volume average particle diameter of the toner particles is a value measured with a Coulter Multisizer (manufactured by Coulter Counter Co.) at an aperture diameter of 100 μm.

The obtained toner particles are mixed with the above-mentioned small-sized inorganic fine particles and large-sized inorganic fine particles using a mixer such as a Henschel mixer to prepare a non-magnetic one-component developer.

The non-magnetic one-component developer of the present invention thus obtained comprises a colorant, a binder resin, a charge control agent,
By appropriately selecting a wax or the like, it can be used as a full color developer or a black developer, but in the present invention, it is effective to use a full color developer. For this reason, the developer of the present invention can be used in any developing device as long as it is a developing device employing a one-component developing method, but is particularly preferably used in a full-color image forming apparatus. Hereinafter, an example of a full-color image forming apparatus will be described with reference to FIG.

In FIG. 1, the full-color laser beam printer is generally driven to rotate in a direction indicated by an arrow a, a photosensitive drum 10, a laser scanning optical system 20, a full-color developing device 30, and driven in a direction indicated by an arrow b. It comprises an endless intermediate transfer belt 40 and a paper feed unit 60. Around the photosensitive drum 10, a photosensitive drum 10
A charging brush 11 for charging the surface of the photosensitive drum to a predetermined potential and a cleaner 12 having a cleaner blade 12a for removing toner remaining on the photosensitive drum 10 are provided.

The laser scanning optical system 20 is a well-known type having a built-in laser diode, polygon mirror, and fθ optical element, and its control unit includes C (cyan), M (magenta), and Y.
(Yellow) and Bk (black) print data are transferred from the host computer. The laser scanning optical system 20 sequentially outputs print data for each color as a laser beam, and scans and exposes the photosensitive drum 10. This allows
An electrostatic latent image for each color is sequentially formed on the photosensitive drum 10.

The full-color developing device 30 includes C, M, Y, B
The four color developing units 31C, 31M, 31Y, and 31Bk each containing a one-component developer composed of k non-magnetic toners are integrated, and can be rotated clockwise about a support shaft 81 as a fulcrum. Each developing device includes a developing sleeve (developer carrying member) 32, a toner regulating blade (developer regulating member) 34
It has. The toner conveyed by the rotation of the developing sleeve 32 is charged by passing through a pressure contact portion (a regulating portion) between the blade 34 and the developing sleeve 32.

The intermediate transfer belt 40 includes support rollers 41, 4
2 and endlessly stretched over the tension rollers 43 and 44, and are driven to rotate in the direction of arrow b in synchronization with the photosensitive drum 10. A projection (not shown) is provided on a side portion of the intermediate transfer belt 40. By detecting the projection by the microswitch 45, image forming processes such as exposure, development, and transfer are controlled. The intermediate transfer belt 40 is pressed by a rotatable primary transfer roller 46 and is in contact with the photosensitive drum 10. The contact portion is a primary transfer portion T _1. The intermediate transfer belt 40 is in contact with a rotatable secondary transfer roller 47 at a portion supported by the support roller 42. The contact portion is a secondary transfer portion T _2.

Further, a cleaner 50 is provided in a space between the developing device 30 and the intermediate transfer belt 40. The cleaner 50 has a blade 51 for removing residual toner on the intermediate transfer belt 40. The blade 51 and the secondary transfer roller 47 can contact and separate from the intermediate transfer belt 40.

The paper supply unit 60 includes a paper supply tray 61 that can be opened to the front side of the image forming apparatus main body 1, a paper supply roller 62,
And a timing roller 63. The recording sheets S are stacked on a paper feed tray 61, fed one by one to the right in the drawing by the rotation of a paper feed roller 62, and synchronized with an image formed on the intermediate transfer belt 40 by a timing roller 63. To the secondary transfer section. The horizontal conveyance path 65 for the recording sheet is constituted by an air suction belt 66 and the like including the paper feeding section, and a vertical conveyance path 71 provided with conveyance rollers 72, 73, 74 from the fixing device 70 is provided. The recording sheet S is discharged from the vertical conveyance path 71 to the upper surface of the main body 1 of the image forming apparatus.

Here, the printing operation of the full-color printer will be described. When the printing operation is started, the photosensitive drum 10 and the intermediate transfer belt 40 are driven to rotate at the same peripheral speed, and the photosensitive drum 10 is charged to a predetermined potential by the charging brush 11.

Subsequently, exposure of the cyan image is performed by the laser scanning optical system 20, and an electrostatic latent image of the cyan image is formed on the photosensitive drum 10. This electrostatic latent image is immediately developed by the developing device 31C, and the toner image is transferred onto the intermediate transfer belt 40 in the primary transfer section. Immediately after the end of the primary transfer, the developing device 31M is switched to the developing section D, and then exposure, development, and primary transfer of the magenta image are performed. Further, switching to the developing device 31Y, exposure, development, and primary transfer of the yellow image are performed. Further, switching to the developing device 31Bk, exposure of a black image, development, and primary transfer are performed, and a toner image is superimposed on the intermediate transfer belt 40 for each primary transfer.

When the final primary transfer is completed, the recording sheet S is sent to the secondary transfer section, and the full-color toner image formed on the intermediate transfer belt 40 is transferred onto the recording sheet S. When the secondary transfer is completed, the recording sheet S is conveyed to the belt-type contact heat fixing device 70, where the full-color toner image is fixed on the recording sheet S, and
Is discharged to the upper surface of the The present invention is described in more detail by the following examples.

[0071]

EXAMPLES In this example, the polyester resins A to A used
The method for producing C is described below. (Production of polyester resin A (for color toner)) Polyoxypropylene (2,2) -2,2- was placed in a glass four-necked flask equipped with a thermometer, a stirrer, a falling condenser and a nitrogen inlet tube. Bis (4-hydroxyphenyl) propane, polyoxyethylene (2,2) -2,2-
Bis (4-hydroxyphenyl) propane and terephthalic acid were charged in a molar ratio of 5: 5: 9.5. After further adding a polymerization initiator (dibutyltin oxide), these were reacted with stirring in a mantle heater under a nitrogen atmosphere at 220 ° C. to obtain a number average molecular weight (Mn) of 4800.
Weight average molecular weight / number average molecular weight 4.5, softening point 108
° C, glass transition point 66 ° C, acid value (AV) 4.2 KOHm
g / g of polyester resin A was obtained.

(Production of Polyester Resin B (for Black Toner)) Polyoxypropylene (2,2) -2 was placed in a glass four-necked flask equipped with a thermometer, a stirrer, a falling condenser and a nitrogen inlet tube. , 2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2,2)-
2,2-bis (4-hydroxyphenyl) propane, isododecenyl succinic anhydride, terephthalic acid and fumaric acid were charged in a weight ratio of 82: 77: 16: 32: 30. After further adding a polymerization initiator (dibutyltin oxide), these were added in a mantle heater under a nitrogen atmosphere.
The mixture was reacted at 220 ° C. with stirring to obtain a polyester resin B having a softening point of 110 ° C., a glass transition point of 60 ° C., and an acid value of 17.5 KOH mg / g.

(Production of Polyester Resin C (for Black Toner)) Styrene and 2-ethylhexyl acrylate were adjusted to a weight ratio of 17: 3.2, and added to a dropping funnel together with a polymerization initiator, digmilyl peroxide. on the other hand,
In a glass four-necked flask equipped with a thermometer, a stirrer, a falling condenser and a nitrogen inlet tube, polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene ( 2,2) -2,2
-Bis (4-hydroxyphenyl) propane, isododecenyl succinic anhydride, terephthalic acid, 1,2,4-anhydride
Benzene tricarboxylic acid and acrylic acid are added in a weight ratio of 4
It was adjusted to 2: 11: 11: 11: 8: 1 and charged with a polymerization initiator (dibutyltin oxide). While stirring these at 135 ° C. in a mantle heater under a nitrogen atmosphere under a nitrogen atmosphere, styrene or the like was dropped from the dropping funnel, and the temperature was raised and reacted at 230 ° C .; 24.5 KOH mg / g of polyester resin C was obtained.

The molecular weight was determined by gel permeation chromatography (807-IT; manufactured by JASCO Corporation).
And using tetrahydrofuran as a carrier solvent, the molecular weight was determined in terms of polystyrene.

For the softening point, use a flow tester (CF
T-500; manufactured by Shimadzu Corporation) using a 1.0 mm × 1.0 mm die for 1.0 g of the sample at a rate of temperature increase of 3.0 ° C./min. The measurement was performed under the conditions of a load of 30 kg and the temperature at which the sample flowed out by half was defined as the softening point.

The glass transition point was measured by a differential scanning calorimeter (DSC-
200; manufactured by Seiko Denshi Co., Ltd.)
0 mg was measured, and alumina was used as a reference, and the shoulder value of the main endothermic peak in the range of 30 to 80 ° C. was taken as the glass transition point.

The acid value was represented by the number of mg of potassium hydroxide necessary to dissolve the weighed sample in an appropriate solvent and neutralize the acidic group using an indicator such as phenolphthalein.

In this example, the following inorganic fine particles were used as the inorganic fine particles. The method for producing the inorganic fine particles a to g is also shown. Inorganic fine particles A (hydrophobic silica, 55% hydrophobicity, average primary particle size 7 nm, TS500; manufactured by Cabosil Co., Ltd.) Inorganic fine particles B (hydrophobic silica, 48% hydrophobicity, average primary particle size 15 nm, R974; Nippon Aerosil Inorganic fine particles C (hydrophobic silica, hydrophobicity 55%, average primary particle size 50 nm, R809; manufactured by Nippon Aerosil Co., Ltd.)

Inorganic fine particles D (hydrophobic titanium dioxide, rutile type titanium dioxide (MT-150W; manufactured by Teica) having a hydrophobicity of 55% and an average primary particle size of 15 nm, surface-treated with n-hexyltrimethoxysilane) Inorganic fine particles E (hydrophobic titanium dioxide, hydrophobicity 60%,
Anatase type titanium dioxide having an average primary particle size of 20 nm
-Those treated with hexyltrimethoxysilane) Inorganic fine particles F (hydrophobic titanium dioxide, hydrophobicity 57%,
Anatase type titanium dioxide having an average primary particle size of 50 nm
-What is surface-treated with hexyltrimethoxysilane) Inorganic fine particles G (hydrophobic titanium dioxide, hydrophobicity 50%,
Inorganic fine particles F are further surface-treated with a fluorine-based silane coupling agent (CF ₃ (CH ₂ ) ₂ Si (OCH ₃ ) ₃ )

(Inorganic fine particles a)-Average primary particle size 250n
m of titanium dioxide (KR-380; manufactured by Titanium Industry Co., Ltd.) by the following chemical formula (I);

Embedded image Surface-treated with an aminosilane coupling agent represented by

(Inorganic fine particles b)-average primary particle size 250n
m surface-treated titanium dioxide (KR-380; manufactured by Titanium Industry Co., Ltd.) with amino-modified silicone oil (KF-857; manufactured by Shin-Etsu Chemical Co., Ltd.).

(Inorganic fine particles c)-average primary particle size 250n
m of titanium dioxide (KR-380; manufactured by Titanium Industry Co., Ltd.) by the following chemical formula (II);

Embedded image Surface-treated with a quaternary ammonium salt represented by

(Inorganic fine particles d)-Average primary particle size 200n
m obtained by subjecting a synthetic spherical silica (SO-C1; manufactured by Admatechs Co., Ltd.) to a surface treatment with an aminosilane coupling agent represented by the above chemical formula (I).

(Inorganic fine particles e) -Synthetic spherical silica (SO-C3; manufactured by Admatechs Co., Ltd.) having an average primary particle size of 1 μm and surface-treated with an aminosilane coupling agent represented by the above chemical formula (I).

(Inorganic fine particles f) -average primary particle size 1.5 μm
m titanium dioxide (KR-310; manufactured by Titanium Industry Co., Ltd.) surface-treated with an aminosilane coupling agent represented by the above chemical formula (I).

(Inorganic fine particle g)-average primary particle size 250n
m surface-treated titanium dioxide (KR-380; manufactured by Titanium Industry Co., Ltd.) with n-hexyltrimethoxysilane.

The degree of hydrophobicity was determined by adding 50 ml of pure water to a 200 ml beaker, adding 0.2 g of a sample, and adding methanol dehydrated with anhydrous sodium sulfate from a burette while stirring the beaker. Using the point almost disappeared as the end point, the degree of hydrophobicity was calculated from the required amount of methanol by the following formula: [Methanol use amount / (50 + methanol use amount)] × 100.

The method for producing the melt-blended polypropylene wax used as the wax in this example is described below. (Production of melt-blended polypropylene wax) Acid value 0
KOH mg / g non-oxidized polypropylene wax (Viscol 550P; manufactured by Sanyo Chemical Industries, Ltd.) and acid value 52
KOH mg / g oxidized polypropylene wax (UMEX 1010; manufactured by Sanyo Chemical Industries, Ltd.) in a weight ratio of 92:
8, melt-kneaded, cooled and pulverized to obtain an acid value of 4.0 KOH mg / g and a melt viscosity at 160 ° C of 20.
A melt-blended polypropylene wax having a softening point of 5 ° C. and a melting point of 150 ° C. was obtained.

Example 1 A polyester resin A and a cyan pigment (CI Pigment Blue 15-3) were charged and kneaded in a pressure kneader at a weight ratio of 7: 3. After cooling the obtained kneaded material, it was pulverized with a feather mill to obtain a pigment master batch.

Polyester resin A93 parts by weight, pigment master batch 10 parts by weight, polypropylene wax (Viscol TS200; manufactured by Sanyo Chemical Industries, Ltd .; acid value: 3.
2 parts by weight of 5KOH mg / g) and 1.5 parts by weight of a zinc salicylate complex (E84; manufactured by Orient Chemical Industries) are sufficiently mixed by a ball mill, and the mixture is subjected to a twin-screw extruder (PC).
M-30; Ikegai Iron Works Co., Ltd.)
Then, it was coarsely pulverized with a feather mill. This coarsely pulverized product was finely pulverized with a jet mill and classified into fine powder to obtain toner particles having a volume average particle size of 8.0 μm.

To 100 parts by weight of the obtained toner particles, 0.5 part by weight of inorganic fine particles A, 0.7 part by weight of inorganic fine particles F and 1.0 part by weight of inorganic fine particles a were added and mixed by a ball mill to obtain a developer. Was.

Examples 2 to 11 and Comparative Examples 1 to 5 Developers were obtained in the same manner as in Example 1 except that the inorganic fine particles shown in Table 1 or Table 2 were used in the indicated amounts.

Example 12 A developer was obtained in the same manner as in Example 1 except that toner particles having a volume average particle diameter of 6.1 μm were prepared and used.

Example 13 40 parts by weight of a polyester resin B, 60 parts by weight of a polyester resin C, polyethylene wax (800P; manufactured by Mitsui Petrochemical Industries, Ltd .; melt viscosity at 160 ° C. 5400)
cps; softening point 140 ° C.) 1 part by weight, melt-blended polypropylene wax 3 parts by weight, acidic carbon black (Mogal L; manufactured by Cabot Corporation; pH 2.5; average primary particle size 24 nm) 8 parts by weight and zinc salicylate complex (E
84; Orient Chemical Industries Co., Ltd.) 2.5 parts by weight were sufficiently mixed with a Henschel mixer, and the mixture was melt-kneaded with a twin-screw extruder (PCM-30; manufactured by Ikegai Iron Works), cooled, and then hammer milled. And coarsely pulverized. This coarsely pulverized product was finely pulverized by a jet pulverizer and classified into fine powder to obtain toner particles having a volume average particle size of 8.2 μm.

To 100 parts by weight of the obtained toner particles, 0.6 parts by weight of inorganic fine particles B, 1.0 part by weight of inorganic fine particles C and 1.0 part by weight of inorganic fine particles a were added and mixed by a ball mill to obtain a developer. Was.

Example 14 A developer was obtained in the same manner as in Example 13 except that the inorganic fine particles shown in Table 1 were used in the amounts indicated.

Using an electrophotographic printer (SP1000; manufactured by Minolta) equipped with a non-magnetic one-component developing device in which the pressure force of the evaluation regulating blade is variably changed, a normal temperature and normal humidity environment (25 ° C., 4 ° C.) is used.
(5%), 30 g of the developer was set, and continuously driven in a blank paper mode setting to evaluate a thin layer formation and a regulating blade.

(Thin layer formation) One minute from the start of continuous driving, 30 minutes
After one minute and one hour, the driving was stopped and the state of forming a thin layer on the developer carrying member (sleeve) was observed, and evaluated according to the following ranking. ；: No streaks or unevenness was observed in the formed thin layer, and no toner spill or dust was generated. Δ: Some streaks or unevenness were observed in the formed thin layer, but toner spill or dust was not observed. There was almost no occurrence and there was no problem in practical use; ×; streaks or unevenness occurred in the formed thin layer,
From that portion, toner spills and powder smoke were remarkably generated.

(Regulatory Blade) One hour after the start of continuous driving, the drive is stopped, the developer regulating member (regulator blade) is removed, and the attached toner is blown off with air gently to observe the surface condition of the regulator blade. Was evaluated according to the following ranking. a: no foreign matter (dust) was present on the blade; b: white lumps or aggregates of toner components were present on portions of the blade corresponding to streaks or unevenness of the thin layer on the sleeve.

The above evaluation results are shown in Tables 1 and 2 together with the processing conditions in the above Examples and Comparative Examples.
Indicated by

[0101]

[Table 1]

[0102]

[Table 2]

[0103]

According to the present invention, even if copying is repeated,
It is possible to provide a non-magnetic one-component developer which is not only capable of maintaining the toner characteristics with a small change in the surface state of the toner and not generating dust and smoke in a developing device and having excellent durability.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a full-color image forming apparatus.

[Explanation of symbols]

10: Photoconductor drum, 11: Charging brush, 12: Cleaner, 20: Laser scanning optical system, 30: Full color developing device, 32: Developer carrier (sleeve), 33: Support shaft,
34: developer regulating member (blade), 40: intermediate transfer belt, 41: support roller, 42: support roller, 43: tension roller, 44: tension roller, 46: primary transfer roller, 47: secondary transfer roller, 60: paper feed unit, 6
1: paper feed tray, 62: paper feed roller, 63: timing roller, 66: air suction belt, 70: fixing device, 71: vertical transport path.

Claims (2)

[Claims] 1. Negatively charged toner particles containing at least a binder resin and a colorant, having an average primary particle size of 1 to 70.
nm small-diameter inorganic fine particles, and an average primary particle diameter of 100 to
A non-magnetic one-component developer containing 500 nm large-diameter inorganic fine particles, wherein the small-diameter inorganic fine particles are surface-treated by a hydrophobizing agent, and the large-diameter inorganic fine particles have a surface having a cationic group. A non-magnetic one-component developer, which is surface-treated with a processing agent. 2. The content of the inorganic fine particles having a small particle size is 0.3 to 3.0% by weight based on the toner particles, and the content of the inorganic fine particles having a large particle size is 0.3 to 3% by weight based on the toner particles. 0.0% by weight
The non-magnetic one-component developer according to claim 1, wherein