JP2002006557A - Nonmagnetic single-component color toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonmagnetic single-component color toner, capable of stabilizing image quality over a long periods of time, without lowering the initial printing quality. SOLUTION: The nonmagnetic single-component color toner contains resin particles, consisting essentially of a bonding resin and a colorant and two additives different from each other in polarity added to the surfaces of the resin particles. The average particle diameter of the primary particles of each of the two additives is >=30 nm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner used in a developing device for enhancing an electrostatic latent image in an electrophotographic method, and more particularly to a non-magnetic one-component color toner.

[0002]

2. Description of the Related Art FIG. 1 is a sectional view showing a structure of a developing device of a general image forming apparatus. As shown in FIG. 1, in a non-magnetic one-component developing method which is mainly used in full-color electrophotographic technology, toner is frictionally charged by a toner replenishing roller 3 and a toner conveying roller (developing roller) 2, and furthermore, a toner layer thickness regulation. The member 4 (doctor blade) is thinned to obtain a sufficient charge amount, and the toner is transferred and adhered to the portion of the electrostatic latent image holder 1 where the electrostatic latent image is formed, thereby forming the electrostatic latent image. It becomes noticeable and participates in development. The toner image formed on the electrostatic latent image holder 1 is transferred onto a separately supplied sheet. At this time, a charge having a polarity opposite to that of the toner image is applied to the back surface of the sheet. Then, the toner image transferred onto the paper is fixed by heat and pressure as the holding roller rotates between the heat roller and the pressure roller.

That is, the toner in this system must obtain a charge amount for forming a clear visual image in a simplified developing mechanism. Has become a major issue.

As a method of simultaneously controlling the charge amount and the fluidity of the toner, which are particularly important factors in the physical properties of the toner, in a non-magnetic one-component color toner, several kinds of external additives have conventionally been used. There is known a method of adding to the toner surface.

[0005] That is, the particle diameters (primary particle diameter = average particle diameter of primary particles) of the several kinds of external additives are arbitrarily changed to different particle diameters. For example, it is a common practice to add two types of external additives having a large or small particle size.
A large particle size external additive having a primary particle diameter of 30 nm or more mainly controls the charge amount of the toner, and the other type is a small particle size external additive having a primary particle size of less than 20 nm, and is mainly composed of toner fluidity. Control the
In this way, image stabilization is achieved.

In Japanese Patent Application Laid-Open No. Hei 10-171155, the chargeability is improved by including an inorganic oxide that is positively charged when an external additive is frictionally charged with iron powder and an inorganic oxide that is negatively charged. There is disclosed an invention which secures and reduces fog and ghost caused by delay of rising of charging.
Also in the present invention, an external additive having a large or small particle diameter of a negatively charged inorganic oxide having a primary particle diameter of 30 nm or more and a positively charged inorganic oxide having a primary particle diameter of less than 20 nm is added.

Further, in recent years, the demand for full-color printers has been greatly increased, and at the same time, the market cost has been rapidly decreasing. To cope with this low-cost era, the cost of the engine body has been reduced while consumables ( The running cost is also reduced by extending the life of the developing device and the photoconductor. Under such circumstances, in a non-magnetic one-component developing device, as a means for stabilizing the image quality as the life of the developing device is extended, the physical properties of the toner (charge amount, fluidity) are generally used.
In order to achieve this, it is necessary to optimize the toner shape and particle size distribution. This is the addition of external additives.

[0008]

However, in order to improve the fluidity, a small particle size external additive that is often employed is:
In general, since the toner is buried in the toner together with the printing durability of the developing device, the fluidity improving effect of the small particle size external additive is limited to a certain number of printing durability, and it is difficult to stabilize the image quality for a long time. Become. To cope with this, it is conceivable to increase the amount of the external additive to be added. In this case, however, fixing performance such as occurrence of fixing offset is lowered as an initial image.

In other words, the addition of a small particle size external additive so as to satisfy long-term stabilization of image quality is a means which is likely to cause side effects in the initial printing quality, and this lowers the initial printing quality. However, it has been a problem to stabilize the image quality for a long period of time in order to extend the life of the developing device.

Accordingly, an object of the present invention is to provide a non-magnetic one-component color toner capable of stabilizing image quality for a long period of time without deteriorating initial print quality. I do.

[0011]

The non-magnetic one-component color toner of the present invention comprises a resin particle comprising at least a binder resin and a colorant, and two kinds of particles having different polarities added to the surface of the resin particle. A non-magnetic one-component color toner containing an additive, wherein the primary particles of the two additives each have an average particle diameter of 30 nm or more.

[0012]

DETAILED DESCRIPTION OF THE INVENTION The invention according to claim 1 contains at least resin particles composed of a binder resin and a colorant, and two additives having different polarities added to the surface of the resin particles. A non-magnetic one-component color toner, wherein the average particle diameter of both primary particles of the two additives is 30 nm or more, which can impart fluidity to the toner and a developing roller The stability of the toner charge amount is good, and the image quality can be stabilized for a long time without lowering the initial print quality.

According to a second aspect of the present invention, in the first aspect, the two kinds of additives are added in an amount of 0.05 to 3 parts by weight with respect to 100 parts by weight of the resin particles. Therefore, there is no occurrence of the offset phenomenon, the photosensitive member, the toner conveying roller, the toner layer thickness regulating member, and the fixing roller are not damaged, and the image quality can be stabilized for a long time.

According to a third aspect of the present invention, in the first and second aspects, the two kinds of additives are both made of an inorganic oxide, which imparts suitable fluidity to the toner, The stability of the charge amount can be improved.

According to a fourth aspect of the present invention, in the third aspect, both of the two kinds of inorganic oxides are made of hydrophobic silica, so that the fluidity is optimally imparted to the toner and the toner is charged. The stability of the quantity can be improved.

According to a fifth aspect of the present invention, in the first to fourth aspects, the binder resin is made of a polyester resin, has a good fixing property, and has a coloring property and a durability as a toner. Can be improved.

According to a sixth aspect of the present invention, in the fifth aspect, the weight average molecular weight of the polyester resin is 10,000.
In this case, the offset phenomenon can be prevented, the melting suitability is good, and the fixing failure can be prevented.

According to a seventh aspect of the present invention, in the first to sixth aspects, the weight distribution average particle diameter is 6 to 10 μm, and the occurrence of a toner flying phenomenon and fogging is prevented. And the image resolution performance does not deteriorate.

Hereinafter, embodiments of the present invention will be described in detail.

The non-magnetic one-component color toner of the present invention comprises:
It contains at least a binder resin, a colorant, and two types of additives having different polarities, and may further contain other additives, a charge control agent, and the like.

First, two types of additives having different polarities, which are added to the non-magnetic one-component color toner of the present invention, will be described.

In the present invention, the two types of additives having different polarities mean a positively charged additive and a negatively charged additive. Therefore, the material of the additive itself may be the same as the positively charged additive and the negatively charged additive, or different materials may be used. In other words, as the additives, the materials described below can be used, but in using these additives, they are used in a state where polarities are different from each other,
It is important to use as a positively charged additive and a negatively charged additive.

The two types of additives having different polarities to be added to the surface of the resin particles of the non-magnetic one-component color toner of the present invention include oxides, double oxides, inorganic oxides, and the like. Metal oxide, metal, silicon compound, carbon, carbon compound, fullerene, boron compound, carbide,
Examples include nitrides and ceramics, and examples of inorganic oxides include silica, titania, alumina, zirconia, zinc oxide, magnesium oxide, cerium oxide, strontium titanate, iron oxide, copper oxide, and tin oxide.

Of these, silica, alumina, and the like, which function as a fluidity improver, are particularly preferable.
These are inorganic oxides such as titania and zirconia, and the surface of these inorganic oxides is a silane compound having a nitrogen element-containing substituent such as aminosilane or a silicone oil having a nitrogen element-containing substituent such as amino-modified silicone oil. Is preferably subjected to a hydrophobic treatment. For example, hydrophobic silica can be used. These additives are externally added to the surface of the resin particles of the toner.

The average particle size of the primary particles of these additives is 30 nm or more for positively charged additives and 30 nm or more for negatively charged additives. That is, both the positively charged additive and the negatively charged additive are 30 nm or more.

The average particle size of the primary particles of the additive is 30 n
If the value is smaller than m, the toner charge amount on the developing roller is not stable, and the initial print quality may be reduced.
Long-term stabilization of image quality cannot be achieved.

The average particle size of the primary particles of these additives is as follows for both positively charged additives and negatively charged additives.
Preferably it is 500 nm or less. If it is larger than 500 nm, there is a problem that the photosensitive member, the toner conveying roller (developing roller), the toner layer thickness regulating member (doctor blade), and the fixing roller are damaged.

Therefore, it is preferable that both the average particle diameter of the primary particles of the positively charged additive and the negatively charged additive be 30 nm or more and 500 nm or less.

The average particle size of the primary particles of the additive is as follows:
It is a number distribution average particle diameter.

The amount of these additives is 0.05 parts by weight ≦ additive amount ≦ with respect to 100 parts by weight of the resin particles of the non-magnetic one-component color toner.
3 parts by weight, which is a negatively charged additive.
0.05 parts by weight ≦ addition amount ≦ 3 parts by weight with respect to 0 parts by weight.

That is, both the positively charged additive and the negatively charged additive are preferably added in an amount of 0.05 to 3 parts by weight with respect to 100 parts by weight of the resin particles.

If the amount added is less than 0.05 parts by weight,
When the image quality cannot be stabilized for a long period of time and exceeds 3 parts by weight, an offset phenomenon in which the toner is transferred to the fixing roller occurs, and the photosensitive member, the toner conveying roller (developing roller), and the toner layer thickness regulating member ( Doctor blade), and there is a problem that the fixing roller is damaged. More preferably, the amount is 0.2 to 2 parts by weight.

Further, in the case of a positively chargeable toner, the mixing ratio of the positively charged additive and the negatively charged additive is such that the mixing ratio of the positively charged additive / negatively charged additive is 50 /. 5
In the case of a negatively chargeable toner, the mixing ratio of the positively charged additive / negatively charged additive is in the range of 10/90 to 50/50.

As described above, it is preferable that the polarity of the toner is determined by the charge control agent described later, and the mixing ratio of the external additive is adjusted to this. The reason for this is that if the proportion of the external additive having too low polarity is increased, image defects such as fogging may occur.

The following resins can be used as the binder resin.

Polyester resin, epoxy resin, polyol resin, styrene-acrylic resin, polyvinyl chloride, phenolic resin, phenol resin modified with natural resin,
Maleic acid resin, natural resin modified maleic acid resin, acrylic resin, methacrylic resin, acrylic phthalate resin,
Polyvinyl acetate, silicone resin, polyurethane, polyamide resin, polyvinyl butyral, terpene resin, coumarone indene resin, polycarbonate, fluorine resin, aliphatic or aliphatic hydrocarbon resin, aromatic petroleum resin, modified rosin, paraffin, natural Waxes, synthetic waxes and the like can be mentioned, and these resins can be used alone or in combination of two or more.

Further examples include styrenes such as styrene, chlorostyrene, α-methylstyrene and vinylstyrene, monoolefins such as ethylene, propylene, butylene and isobutylene, vinyl acetate, vinyl propionate, vinyl benzoate and butyric acid. Vinyl esters such as vinyl, acrylic acid such as methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate Alkyl ethers and methacrylic acid alkyl esters, vinyl methyl ether, vinyl ethyl ether, vinyl ethers such as vinyl butyl ether,
Examples include homopolymers or copolymers of vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, and vinyl isopropenyl ketone.

Typical examples thereof include polystyrene and poly-
Homopolymers of styrene such as p-chlorostyrene and polyvinyltoluene and substituted products thereof, styrene-p-chlorostyrene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-alkyl acrylate Ester copolymer, styrene-alkyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer Copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-acrylonitrile-indene copolymer, styrene-based copolymer such as styrene-maleic anhydride copolymer, polyethylene, ethylene-vinyl acetate copolymer Polymer, ethylene bi Ethylene copolymer of alcohol copolymer, and polypropylene.

These homopolymers or copolymers can be used alone or in combination of two or more.

Among the above binder resins, polyester resins have sharp melting suitability and good fixability. Further, it is possible to improve the coloring property and the durability of the toner, which is particularly preferable.

The weight average molecular weight of the polyester resin is preferably 10,000 or more and 25,000 or less. That is, if it is less than 10,000, there is a problem that a so-called offset phenomenon occurs in which the toner is transferred to the fixing roller in the toner fixing step, and 25,000.
If it is larger than this, there is a problem that the meltability is deteriorated and a fixing failure occurs, which is not preferable.

Further, as the colorant used in the non-magnetic one-component color toner of the present invention, any organic or inorganic pigment or dye is used.

Pigments such as disazo pigments, insoluble azo pigments, azo lake pigments, copper phthalocyanine pigments and the like can be used.
Dyes such as anthraquinone dyes, xanthene dyes, methine dye basic dyes and oil-soluble dyes can be used.
These pigments and dyes can be used alone or in combination of two or more.

The pigments include phthalocyanine blue, indanthrene blue, peacock blue, fast sky blue, induslen blue, aniline blue, calcoil blue, ultramarine blue, permanent red, watching red calcium salt, brilliant carmine , Lake Red, Rose Bengal, Naphthol Yellow, Hansa Yellow, Rhodamine Yellow, Hansa Yellow, Permanent Yellow, Benzidine Yellow, Naphthol Yellow, Chrome Yellow, Quinoline Yellow, Carbon Black, Aniline Black, Acetylene Black, Lamp Black, Alizarin Lake, Bengala , Rhodamine lake, permanent orange, pyrazolone orange, benzine orange, malachite green oki Rate, quinacridone, fast violet, methyl violet lake, as a blue dye or pigment of copper phthalocyanine and derivatives thereof,
C. I. Pigment Blue 15: 3, C.I. I. Pigment Blue 15, C.I. I. Pigment Blue 16, red or red pigments include C.I. I. Pigment Red 5, C.I. I. Pigment Red 3, C.I. I. Pigment Red 2, C.I. I. Pigment Red 6, C.I. I. Pigment Red 7, C.I. I. Pigment Red 57, C.I.
I. Pigment Red 122, C.I. I. Pigment Red 9, C.I. I. Pigment Red 48, C.I. I. Pigment Red 48: 3, C.I. I. Pigment Red 53:
1, C.I. I. Pigment Red 112, C.I. I. Pigment Red 149, C.I. I. Pigment Red 170,
C. I. Pigment Red 168, C.I. I. Pigment Red 188, C.I. I. Pigment Red 194, C.I.
I. Pigment Red 175, C.I. I. Pigment Red 208, C.I. I. Pigment Red 187, C.I. I.
Pigment Red 57: 1, C.I. I. Pigment Red 81, C.I. I. Pigment Red 122, C.I.
I. Pigment Red 49: 1, benzimidazolone monoazo pigments such as C.I. I. Pigment Yellow 151, C.I. I. Pigment Yellow 154, C.I.
I. Pigment Yellow 156, C.I. I. Pigment Yellow 120, C.I. I. Pigment Yellow 17
5. As an acetoacetic acid arylamide-based disazo yellow pigment, C.I. I. Pigment Yellow 12, C.I. I. Pigment Yellow 13, C.I. I. Pigment Yellow 14, C.I. I. Pigment Yellow 17, C.I. I. Pigment Yellow 83, isoindolinone pigments such as C.I. I. Pigment Yellow 110, C.I. I. Pigment Yellow 109, C.I. I. Pigment Yellow 137, C.I. I. Pigment Yellow 173, acetoacetic arylamide monoazo yellow pigment,
C. I. Pigment Yellow 1, C.I. I. Pigment Yellow 3, C.I. I. Pigment Yellow 74,
C. I. Pigment Yellow 97, C.I. I. Pigment Yellow 98 can be used.

As the dye, C.I. I. Direct Blue 1, C.I. I. Direct Blue 2, C.I. I. Acid Blue 9, C.I. I. Acid Blue 15, C.I. I.
Basic Blue 3, C.I. I. Basic Blue 5,
C. I. Modant Blue 7, C.I. I. Direct Red 1, C.I. I. Direct Red 4, C.I. I. Acid Red 1, C.I. I. Basic Red 1, C.I. I. Basic Red 12, C.I. I. Modern Red 30,
C. I. Solvent Red 49, C.I. I. Solvent Red 52, C.I. I. Solvent Red 109, C.I. I.
Solvent Red 58, C.I. I. Solvent Red 8,
C. I. Solvent Yellow 19, C.I. I. Solvent Yellow 77, C.I. I. Solvent Yellow 7
9, C.I. I. Disperse Yellow 164 can be used.

The additives used in the non-magnetic one-component color toner of the present invention may contain various additives in addition to the above-mentioned two additives having different polarities.

As these additives, fluidity improvers,
Examples include release agents, lubricants, fixing aids, cleaning improvers, conductive substances, extenders, reinforcing fillers such as fibrous substances, antioxidants, antioxidants, and anti-offset agents.
The additives are added to satisfy various characteristics required for the toner or to improve the characteristics.

Further, various waxes may be added, such as fluororesin fine particles, silicone resin fine particles, higher fatty acids such as stearic acid, and metal salts thereof such as zinc stearate and aluminum stearate.

As other additives, release agents include
Low-molecular-weight polypropylene, low-molecular-weight polyethylene, or waxes such as microstalin wax, carnauba wax, sasol wax, and paraffin wax. Further, wax such as polyolefin, polyethylene, and polypropylene also functions as an anti-offset agent. Examples of the lubricant include Teflon (registered trademark), zinc stearate, polyvinylidene fluoride and the like. Low molecular weight polyethylene, low molecular weight polypropylene and the like can be added as a fixing aid. These additives can be used alone or in combination of two or more as needed, and are added internally or externally according to the purpose.

Next, the non-magnetic one-component color toner of the present invention can also contain a charge control agent, and the following charge control agents can be used.

Examples of the charge controlling agent as the negatively chargeable toner include a chromium-zinc-aluminum-boron complex or a salt compound of salicylic acid or a derivative thereof, and a chromium-zinc-aluminum-boron complex or a salt compound of benzylic acid or a derivative thereof. , Tetraphenylborate, chromium azo complex dye, iron azo complex dye, cobalt azo complex dye, chromium zinc of naphtholic acid or its derivative
Surface active agents such as aluminum-boron complex or salt compound, long-chain alkyl carboxylate, and long-chain alkyl sulfonate.

The charge control agent as a positively chargeable toner includes cetyltrimethylammonium bromide, quaternary ammonium salt, N, N-dialkylaminoalkyl (meth) acrylates, and N, N-dialkylaminoalkyl (meth) acrylate. Radical polymerizable copolymers obtained by copolymerizing monomers having a nitrogen-containing functional group of acrylamides, nigrosine dyes and derivatives thereof, triphenylmethane derivatives, quaternary phosphonium salts, quaternary pyridinium salts, guanidine salts, derivatives such as amidine salts And the like.

Next, a method for producing the non-magnetic one-component color toner of the present invention will be described.

The non-magnetic one-component color toner of the present invention can be produced by a kneading and pulverizing method.
Other than the kneading and pulverizing method, there is a polymerization method and the like.

In the kneading and pulverizing method, first, a binder resin, a colorant, a charge control agent, and various internal additives are mixed.

As a mixing method, a Henschel mixer,
It can be performed by a known mixer such as a ball mill.

After being sufficiently mixed in a mixer, the mixture is melt-kneaded, and the colorants, the charge control agent, and the internal additives are dispersed or dissolved while the resins are mutually compatible.

The kneading method at this time can be performed using a known melt kneader. As the heating kneader, there can be used a device such as a three-roll type, a single screw type, a twin screw type, or a Banbury mixer type that heats and kneads a kneaded material by applying a shearing force.

Next, the melt-kneaded product is cooled and solidified.

Further, this lump is coarsely pulverized by a cutter mill or the like, then pulverized by a jet mill pulverizer, and fine powder particles are cut by a classifier such as an airflow classifier to obtain a desired color toner. .

At this time, by appropriately adjusting the classifier, color toner resin particles having a desired weight distribution average particle diameter can be obtained.

The weight distribution average particle diameter of the color toner of the present invention is preferably from 6 to 10 μm. The reason is 6
When the diameter is smaller than μm, the flying phenomenon of the toner becomes remarkable, and fogging easily occurs. Also, 10
When it is larger than μm, there is a problem that image resolution performance is deteriorated.

The particle size distribution of the toner can be measured by various methods. For the measurement of the non-magnetic one-component color toner of the present invention, a Coulter counter was used. The Coulter counter is an apparatus for measuring the number, diameter and volume of fine particles by an electric resistance method. In this invention, it measured using the Coulter counter TA-II type (made by Coulter). The aperture used is a 100 μm aperture. The volume and the number of the toner are measured, and the volume distribution and the number distribution of the particles are calculated. Thereby, the weight distribution average particle diameter calculated from the number distribution average particle diameter and the volume distribution can be obtained.

When two kinds of additives (for example, inorganic oxides such as silica, alumina, titania and zirconia) of the present invention are added, a high-speed stirrer such as a super mixer or a Henschel mixer may be used. Can be used to stir and mix the color toner and the external additive to add the external additive to the toner surface.

As described above, the colorant can be contained in the toner at the time of melt-kneading. However, by dispersing the colorant by using it in advance as a master batch that has been melt-kneaded at a high concentration with the binder resin. It will be easier. Similarly, the charge control agent can also be used as a masterbatch previously melt-kneaded at a high concentration with the binder resin. If it is difficult to simultaneously mix and disperse all of the mixture to be contained in the binder resin, such as the colorant, the charge control agent, and the internal additive, the colorant, the charge control agent, The additives may be melt-kneaded in advance with the binder resin, and then the colorant-dispersed resin, the charge control agent-dispersed resin, the internal additive-dispersed resin and the binder resin may be melt-kneaded.

[0066]

Next, the present invention will be described in detail with reference to examples of the present invention and comparative examples. The present invention is not limited at all by the following Examples and Comparative Examples.

Example 1 The material composition of the toner used in Example 1 is shown below. Binder resin Polyester resin 91.0 parts by weight Colorant C.I. I. Pigment Blue 15: 3 4.5 parts by weight Charge control agent Zinc salt of salicylic acid derivative 4.5 parts by weight (“E-84” manufactured by Orient Chemical Industries, Ltd.) The mixture is mixed well with a ball mill or the like, heated and kneaded with a twin-screw kneading extruder, cooled, coarsely ground with a cutter mill, finely ground with a jet mill, and finely ground with a gas flow classifier. To obtain the color toner resin particles of Example 1.

As a result of measurement using the Coulter Counter TA-II (manufactured by Coulter Inc.), the color toner resin particles of Example 1 had a weight distribution average particle size of 9.7.
0 (μm).

Further, the following two additives were added to 100 parts by weight of the color toner resin particles of Example 1, and mixed and adhered using a Henschel mixer to obtain a color toner of Example 1. . Positively charged additive hydrophobic silica, average particle size of primary particles 30 nm 0.5 parts by weight Negatively charged additive hydrophobic silica, average particle size of primary particles 30 nm 1.5 parts by weight The polarity of the color toner of the first embodiment is a negative polarity and is a negatively charged toner.

Example 2 In the same manner as in Example 1, the materials having the above composition were mixed, heated and kneaded, cooled, roughly pulverized.
By finely pulverizing and classifying and appropriately adjusting the classifier, the color toner resin particles of Example 2 were obtained.

As in Example 1, the following 2 was added to 100 parts by weight of the color toner resin particles of Example 2.
Various additives were added and mixed and attached using a Henschel mixer to obtain a color toner of Example 2. Positively charged additive hydrophobic silica, average particle diameter of primary particles 40 nm 0.9 parts by weight Negatively charged additive hydrophobic silica, average particle diameter of primary particles 40 nm 2.5 parts by weight The polarity of the color toner of the first embodiment is a negative polarity and is a negatively charged toner.

Here, the average particle diameters and the polarities of the primary particles of the two additives in Examples 1 and 2 are summarized in Table 1.

[0073]

[Table 1]

(Comparative Example 1) For comparison, Example 1 was used.
In the same manner as in the above, the materials of the above composition were mixed, heated and kneaded, cooled, coarsely ground, finely ground and classified, and the classifier was appropriately adjusted to obtain color toner resin particles of Comparative Example 1.

In the same manner as in Example 1, the same additives as described below were added to 100 parts by weight of the color toner resin particles of Comparative Example 1 and mixed and adhered using a Henschel mixer. Was obtained. Negatively charged additive Hydrophobic silica, average particle diameter of primary particles 30 nm 0.5 parts by weight Hydrophobic silica, average particle diameter of primary particles 16 nm 0.4 parts by weight The obtained color of Comparative Example 1 The polarity of the toner is negative and the toner is negatively charged.

(Comparative Example 2) For comparison, Example 1 was used.
In the same manner as in the above, the color toner resin particles of Comparative Example 2 were obtained by mixing, heating and kneading, cooling, coarsely pulverizing, finely pulverizing and classifying the materials having the above-mentioned composition, and appropriately adjusting the classifier.

Further, in the same manner as in Example 1, the same additives as described below were added to 100 parts by weight of the color toner resin particles of Comparative Example 2 and mixed and adhered using a Henschel mixer. Was obtained. Negatively charged additive Hydrophobic silica, average particle diameter of primary particles 40 nm 0.9 parts by weight Hydrophobic silica, average particle diameter of primary particles 16 nm 0.4 parts by weight The obtained color of Comparative Example 2 The polarity of the toner is negative and the toner is negatively charged.

(Comparative Example 3) For comparison, Example 1 was used.
In the same manner as in the above, the color toner resin particles of Comparative Example 3 were obtained by mixing, heating and kneading, cooling, coarsely pulverizing, finely pulverizing and classifying the materials having the above-mentioned composition, and appropriately adjusting the classifier.

Further, in the same manner as in Example 1, the same additives as described below were added to 100 parts by weight of the color toner resin particles of Comparative Example 3 and mixed and adhered using a Henschel mixer. Was obtained. Negatively charged additive Hydrophobic silica, average particle diameter of primary particles 30 nm 0.5 parts by weight Hydrophobic silica, average particle diameter of primary particles 7 nm 0.1 parts by weight The color of Comparative Example 3 obtained here The polarity of the toner is negative and the toner is negatively charged.

(Comparative Example 4) For comparison, Example 1 was used.
In the same manner as in the above, materials of the above composition were mixed, heated and kneaded, cooled, coarsely pulverized, finely pulverized, and classified, and the classifier was appropriately adjusted, whereby color toner resin particles of Comparative Example 4 were obtained.

Further, as in Example 1, the following 2 was added to 100 parts by weight of the color toner resin particles of Comparative Example 4.
Various additives were added and mixed and attached using a Henschel mixer to obtain a color toner of Comparative Example 4. Positively charged additive hydrophobic silica, primary particle average particle diameter 12 nm 1.5 parts by weight Negatively charged additive hydrophobic silica, primary particle average particle diameter 30 nm 0.1 part by weight Obtained Further, the polarity of the color toner of Comparative Example 4 is a negative polarity and is a negatively charged toner.

Comparative Example 5 For comparison, Example 1 was used.
In the same manner as described above, the color toner resin particles of Comparative Example 5 were obtained by mixing, heating and kneading, cooling, coarsely pulverizing, finely pulverizing and classifying the materials having the above-mentioned composition, and appropriately adjusting the classifier.

As in Example 1, the following 2 was added to 100 parts by weight of the color toner resin particles of Comparative Example 5.
Various additives were added and mixed and attached using a Henschel mixer to obtain a color toner of Comparative Example 5. Positively charged additive hydrophobic silica, average particle size of primary particles 30 nm 0.5 parts by weight Negatively charged additive hydrophobic silica, average particle size of primary particles 16 nm 0.4 parts by weight Further, the polarity of the color toner of Comparative Example 5 is negative polarity and is a negatively charged toner.

(Comparative Example 6) For comparison, Example 1 was used.
In the same manner as described above, the color toner resin particles of Comparative Example 6 were obtained by mixing, heating and kneading, cooling, coarsely pulverizing, finely pulverizing, and classifying the materials having the above composition, and appropriately adjusting the classifier.

In the same manner as in Example 1, to 100 parts by weight of the color toner resin particles of Comparative Example 6, the same additives as described below were added, and mixed and adhered using a Henschel mixer. Was obtained. Positively charged additive Hydrophobic silica, average particle size of primary particles 30 nm 1.5 parts by weight Hydrophobic silica, average particle size of primary particles 12 nm 0.1 parts by weight The color of Comparative Example 5 obtained The polarity of the toner is negative and the toner is negatively charged.

Here, the average particle diameter and the polarity of the primary particles of each additive in Comparative Examples 1 to 6 are summarized in Table 2 below.

[0087]

[Table 2]

Further, in Examples 1 and 2 and Comparative Examples 1 to 6,
Was charged into a non-magnetic one-component developing device, and a continuous printing life test was performed on 10,000 sheets.

The test results are shown in (Table 3).

[0090]

[Table 3]

Here, the evaluation methods and evaluation criteria in the evaluation items of (Table 3) will be described.

The weight distribution average particle size after the life test was
As described above, the weight distribution was measured using a Coulter Counter TA-II type (manufactured by Coulter), compared with the weight distribution average particle diameter before the life test, and the increase in the weight distribution average particle diameter due to the toner selection phenomenon was evaluated. .

The evaluation criteria were as follows: ：: the average particle diameter was small, the increase was good, and Δ: the average particle diameter was a tendency to increase.

The stability of the charge amount is obtained by actually sucking the color toner on the toner conveying roller (developing roller), and determining the charge remaining on the toner conveying roller and the weight of the sucked color toner. Evaluation was made based on the difference between the initial charge amount and the charge amount of the 10,000th print after the life test.

The evaluation criteria were as follows: ：: small decrease in charge amount and good, Δ: small decrease in charge amount.

The stability of the image density is to confirm the change over time of the printed image density.
The image density of the zeroth sheet is measured with a Macbeth densitometer (manufactured by Macbeth). Then, evaluation was made based on the difference in the concentration change.

Evaluation criteria are as follows: ：: less than 15% density change;
Δ: Density change 15% or more and less than 25% X: Density change 15
% Or more.

The fogging is a phenomenon of toner flying to a non-image portion, and the degree of contamination of the non-image portion was determined as a fogging ratio by calculating an occupied area ratio by an image processing apparatus.

The evaluation criteria were as follows: か: fog rate of less than 0.4%,
Δ: fog rate of 0.4% or more and less than 1.0%, x: fog rate of 1.0% or more.

Character dust is a phenomenon in which toner flies around a character portion. The degree of the flying toner is evaluated by reproducibility of fine lines of 600 dpi dots, and is visually judged (optical microscope).

The evaluation criteria were: ○: good fine line reproducibility, Δ:
The thin line was broken, and X: the thin line was not reproduced.

The solid followability was evaluated by visually checking whether or not the image was blurred in the printing direction when a full solid image was printed.

The evaluation criteria were as follows: ○: no image blur, Δ: light density blur, x: white blurred portion.

As is apparent from these results, the color toners of Examples 1 and 2 of the present invention had excellent characteristics as compared with Comparative Examples 1 to 6.

[0105]

As described above, according to the present invention, the stability of the charge amount of the toner on the developing roller in the non-magnetic one-component developing method is good, and the image quality can be stabilized for a long time without lowering the initial print quality. Can be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a developing device of a general image forming apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 electrostatic latent image holder 2 toner transport roller 3 supply roller 4 toner layer thickness regulating member 5 toner transport paddle

Claims (7)

[Claims] 1. A non-magnetic one-component color toner comprising at least resin particles comprising a binder resin and a colorant, and two additives having different polarities added to the surface of the resin particles. A non-magnetic one-component color toner, wherein the primary particles of the two additives each have an average particle diameter of 30 nm or more. 2. The resin composition according to claim 1, wherein the two additives are selected from the group consisting of
2. The non-magnetic one-component color toner according to claim 1, wherein 0.05 to 3 parts by weight are added to each part by weight. 3. The non-magnetic one-component color toner according to claim 1, wherein the two kinds of additives both comprise an inorganic oxide. 4. The non-magnetic one-component color toner according to claim 3, wherein said two kinds of inorganic oxides are both made of hydrophobic silica. 5. The non-magnetic one-component color toner according to claim 1, wherein said binder resin is made of a polyester resin. 6. The non-magnetic one-component color toner according to claim 5, wherein the polyester resin has a weight average molecular weight of 10,000 or more and 25,000 or less. 7. The resin particles having a weight distribution average particle diameter of 6
The non-magnetic one-component color toner according to any one of claims 1 to 6, wherein the thickness of the non-magnetic one-component color toner is from 10 to 10 µm.