JP2001005213A - Electrostatic charge image developing toner and two- component developer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an image free from diffused transfer by using a toner obtained by adding hydrophobic fine rutile type titanium dioxide powder and hydrophobic fine silica powder each having a specified average particle diameter to toner matrix particles. SOLUTION: Hydrophobic fine rutile type titanium dioxide powder having 0.005-0.2 μm average particle diameter and hydrophobic fine silica powder having 0.005-0.2 μm average particle diameter are added as additives to toner matrix particles consisting essentially of a bonding resin, a colorant and an electrostatic charge controlling agent to obtain the objective toner. The ratio of the weight(Wt) of the hydrophobic fine rutile type titanium dioxide powder to the weight(Ws) of the hydrophobic fine silica powder in the toner is preferably 0.5<=Wt/Ws<=1.3 in the case of a black toner, 0.7<=Wt/Ws<=1.5 in the case of a magenta toner, 0.8<=Wt/Ws<=1.6 in the case of a cyan toner and 0.9<=Wt/Ws<=1.8 in the case of a yellow toner. The electrostatic charge controlling agent is preferably a quaternary ammonium salt, an amino-containing polymer or a complex compound of salicylic acid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a toner and a developer used for developing an electrostatic image in electrophotography, electrostatic recording, electrostatic printing and the like.

[0002]

2. Description of the Related Art Conventionally, various methods for electrophotography have been described in U.S. Pat. No. 2,297,691, JP-B-49-23910, and JP-B-43-24748. Uses photoconductive materials,
An electric latent image is formed on the photoreceptor by various means, then the latent image is developed using dry toner, the toner image is transferred to paper or the like, and then fixed by heating, pressing, etc., and a copy is made. What you get.

[0003] Dry toners used in these methods are:
As is known, a binder resin, a colorant as a main component,
If necessary, additives such as a charge control agent and a release agent are added. Characteristics required for these toners include fixing properties, charging properties, transfer properties, fluidity, environmental stability, mechanical strength, pulverizability, and the like.

In recent years, colorization has been rapidly progressing, but the quality of a color image obtained by electrophotography is not always satisfactory, and the current situation is that improvements are being made every day. The main issues are gloss,
There are color tone reproducibility, transparency and transferability.

Regarding gloss, for example, Japanese Patent Application Laid-Open No. 7-120
Japanese Patent Application Laid-Open No. 996 and Japanese Patent Application Laid-Open No. 7-195958 describe a method for reducing the gloss of a black toner to make the gloss of a four-color copy image uniform.
JP-A-314300 describes an image forming method in which the relationship between the fixing temperature and gloss is defined.
Japanese Patent Application Publication No. 9695 describes a method relating to a fixing speed, a fixing pressure, a fixing temperature and a fixing area as means for controlling gloss.

The color tone reproducibility and transparency are described in, for example, JP-A-50-62442 and JP-A-51-14462.
No. 5, JP-A-59-57256, etc., have transparency from a combination of a novel color binder resin and a colorant,
A toner having a wide reproduction range is described. Further, with respect to the transparency of the toner, for example, Japanese Patent Publication No. 2675950 describes a toner to which a fine powder of hydrophobic anatase type titanium oxide having an average particle diameter, a degree of hydrophobicity, and light transmittance is defined.

According to these proposed electrophotographic toners, the chargeability is stabilized, the transferability is improved, and a color image having a color tone and transparency can be obtained. However, when these toners are used, a phenomenon in which part of an image is still not locally transferred at the time of transfer, "transfer missing", or a visible image is not transferred to a position to which a visible image should be originally transferred at the time of transfer. The phenomenon "transfer dust" that is diffused and transferred to the peripheral portion often occurs.

As a means for avoiding the phenomenon of dropout during transfer, an intermediate transfer member (intermediate transfer belt) is used. However, US Pat. No. 5,053,827, JP-A-7-181732, and US Pat. Kaihei 7-181733
There are various techniques disclosed in Japanese Unexamined Patent Application Publication Nos. However, although such a measure significantly improves the phenomenon of omission during transfer, it has little effect on transfer dust.

[0009] With respect to such color dropout during transfer and transfer dust, the present applicant previously disclosed in Japanese Patent Application Laid-Open No. 10-69147 a combination of hydrophobic fine particles of silica and titanium oxide fine particles as an external additive. We have proposed an electrostatic charge developing toner with good transfer quality. According to the use of this toner, a high-quality toner image can be obtained for a long period of time even under various environments. However, subsequent studies did not show that any type of titanium oxide particles or silica particles were effective, and after conducting research on the combination and charge amount, they concluded that there was still room for improvement. did.

[0010]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to obtain a mono-color or full-color image using one or two or more multicolor toners, and in particular, an electrostatic charge for suppressing the phenomenon of transfer dust. An object of the present invention is to provide a toner for image development. Another object of the present invention is to provide a toner for developing an electrostatic image, which improves the yield representing the number of prints per unit weight of toner.

[0011]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and found that the average particle size is 0.0
The present inventors have found that the above problem can be remarkably improved by using a toner to which fine particles of hydrophobic rutile type titanium oxide and fine particles of hydrophobic silica having a particle size of from 0.5 to 0.2 μm are externally added, and have reached the present invention.

According to the present invention, first, there is provided a toner for developing an electrostatic charge image, wherein an external additive is added to toner base particles containing at least a binder resin, a colorant and a charge control agent as main components, The external additive is a hydrophobic rutile type titanium oxide fine powder having an average particle diameter of 0.005 to 0.2 μm and an average particle diameter of 0.005 to 0.005 μm.
Provided is a toner for developing an electrostatic image, which is used in combination with 0.2 μm hydrophobic silica fine powder.

Second, the ratio of the weight (Wt) of the hydrophobic rutile type titanium oxide fine powder in the toner to the weight (Ws) of the hydrophobic silica fine powder is 0.5 ≦ Wt / Ws ≦ 1.3. The first black toner for developing an electrostatic image is provided.

Third, the ratio of the weight (Wt) of the hydrophobic rutile type titanium oxide fine powder in the toner to the weight (Ws) of the hydrophobic silica fine powder is 0.7 ≦ Wt / Ws ≦ 1.5. The first magenta toner for developing an electrostatic image described above is provided.

Fourth, the ratio of the weight (Wt) of the hydrophobic rutile type titanium oxide fine powder in the toner to the weight (Ws) of the hydrophobic silica fine powder is 0.8 ≦ Wt / Ws ≦ 1.6. There is provided the first cyan toner for developing an electrostatic image described above.

Fifth, the ratio of the weight (Wt) of the hydrophobic rutile type titanium oxide fine powder in the toner to the weight (Ws) of the hydrophobic silica fine powder is 0.9 ≦ Wt / Ws ≦ 1.8. The first yellow toner for developing an electrostatic image is provided.

Sixth, the toner for developing an electrostatic image according to any one of the first to fifth aspects, wherein the charge control agent is a complex compound of a quaternary ammonium salt amino group-containing polymer and salicylic acid. .

Seventh, the first to sixth electrostatic image developing toners are provided, wherein the binder resin is an epoxy resin.

Eighth, the hydrophobic rutile-type titanium oxide fine powder and the hydrophobic silica fine powder are used in an amount of 0.1 to 2.0 parts by weight based on 100 parts by weight of the toner base particles. A non-contact fixing type electrostatic image developing toner according to any one of the above second to seventh aspects is provided.

A two-component developer comprising the toner according to any one of the first to eighth aspects and a carrier which has been subjected to a silicon coating treatment is provided.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. According to the present invention, it is possible to suppress transfer dust in a mono-color or full-color image. Usually, the toner transferred to the first color is a recording medium (paper, OHP)
Since there is no toner on the transfer material such as paper or plastic sheet) or the intermediate transfer belt, the transfer can be performed without causing transfer dust. However, depending on the image pattern, the toner of the second and subsequent colors may have already been transferred onto a recording medium or an intermediate transfer belt, and transfer dust will occur. In particular, the generation of the transfer dust is remarkable in the toner to which the hydrophobic anatase type titanium oxide fine powder used for the purpose of improving the environmental stability of charging is externally added.

The present inventors can externally add hydrophobic rutile-type titanium oxide fine powder and hydrophobic silica fine powder to toner base material particles mainly containing a colorant, a binder resin and a charge control agent. Has been found to be extremely effective in suppressing the fluidity of the toner and improving the phenomenon of transfer dust. It has also been found that the external transfer of hydrophobic rutile-type titanium oxide fine powder and hydrophobic silica fine powder can improve the transfer rate from the photoreceptor to a recording medium or an intermediate transfer belt.

In order to obtain a rutile-type titanium oxide fine powder subjected to a hydrophobic treatment, a hydrophilic fine powder is treated with a silane coupling agent such as methyltrimethoxysilane, methyltriethoxysilane, octyltrimethoxysilane or the like. Obtainable. Further, it can be obtained by polycyclosan treatment. In addition, fatty acid metal salts (zinc stearate, aluminum stearate, etc.), metal oxides (alumina, tin oxide, antimony oxide, etc.), fluoropolymers and the like may be added as additives. Commercially available hydrophobized rutile-type titanium oxide fine powders include MT
-100S, MT-100T, MT-150A, MT-
150AFM (all manufactured by Teika).

Commercially available hydrophobic silica fine powders include HDK H2000, HDKH 2000/4,
HDK H 2050EP, HVK21 (above, manufactured by Hoechst), R972, R974, RX200, RY20
0, R202, R805, and R812 (both manufactured by Nippon Aerosil Co., Ltd.) and TS720 (manufactured by Cabot).

The average particle diameter of the hydrophobic rutile type titanium oxide fine powder and the average particle diameter of the silica fine powder contained in the toner of the present invention are both preferably 0.005 to 0.2 μm.
01 to 0.1 μm is more preferable. Average particle size 0.2μ
If it is larger than m, the fluidity of the toner deteriorates, and toner scattering occurs due to poor charging. On the other hand, when the average particle size is smaller than 0.005 μm, the resin is easily embedded in the resin surface and does not function.

The hydrophobic rutile-type titanium oxide fine powder has the effect of suppressing the charging characteristics of the toner, especially the rise in charge over time, while the silica fine powder has the effect of increasing the charge. These fine powders are preferably used in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the toner base particles, and 0.1 to 2 parts by weight for the non-contact fixing system.
When the amount is less than 0.1 part by weight, the fluidity of the toner particles is remarkably reduced. When the amount is more than 5 parts by weight, all of the fine powder is not attached to the toner base particles but is released. This is because the surface is contaminated and the charge amount of the toner is reduced. In addition, in the non-contact fixing type toner, the upper limit of the amount of addition of these fine powders is set in the toner base particles 1.
The reason why the amount is set to 2 parts by weight with respect to 00 parts by weight is that if the amount of the external additive is large, heat is hardly transmitted to the toner base particles.

In addition, since the kind of the coloring agent differs depending on the color,
In order to secure an appropriate charge amount, the ratio (Wt / Ws) of the hydrophobic rutile-type titanium oxide fine powder (Wt) and the silica fine powder (Ws) must be set for each color. For example,
In the case of a black toner, it is preferable that 0.5 ≦ Wt / Ws ≦ 1.3, and it is more preferable that 0.6 ≦ Wt / Ws ≦ 1.2. Similarly, for magenta toner, 0.7 ≦ Wt
/Ws≦1.5, preferably 0.8 ≦ Wt / Ws ≦ 1.
4 is more preferred. 0.8 ≦ Wt / W for cyan toner
s ≦ 1.6 is preferable, and 0.9 ≦ Wt / Ws ≦ 1.4 is more preferable. 0.9 ≦ Wt / Ws for yellow toner
≦ 1.8, preferably 1.0 ≦ Wt / Ws ≦
1.6 is more preferred. For example, if Wt / Ws is smaller than these ranges, the charge amount of the toner increases and the image density decreases. On the other hand, if Wt / Ws is larger than these ranges, the charge amount of the toner becomes small, the image density becomes high, and toner scattering occurs. The proper charge amount is 2
0-30 (μC / g).

It is important that the toner used in the image forming method of the present invention contains at least one of a polyester resin and an epoxy resin as a binder resin.
Polyester resins and epoxy resins are extremely useful as color binder resins because they have better storage stability and color development than other resins. In particular, when the toner is fixed on a recording medium, the toner is overheated, which may cause odor. However, the epoxy resin is also very excellent in this respect.

The polyester resin used in the present invention is:
Obtained by condensation polymerization of alcohol and carboxylic acid.

Examples of the alcohol used include glycols such as ethylene glycol, diethylene glycol, triethylene glycol and propylene glycol, 1,4-bis (hydroxymeth) cyclohexane,
And etherified bisphenols such as bisphenol A, other dihydric alcohol monomers, and trihydric or higher polyhydric alcohol monomers.

Examples of the carboxylic acid include divalent organic acid monomers such as maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, succinic acid and malonic acid;
1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methylenecarboxypropane, 1,
Examples thereof include trivalent or higher polyvalent carboxylic acid monomers such as 2,7,8-octanetetracarboxylic acid.

The epoxy resin used in the present invention is obtained by polycondensation of bisphenol and epichlorohydrin. Examples of the bisphenol used include ethylene oxide, propylene oxide, butylene oxide, and alkylene oxide adducts of dihydric phenol, which are reaction products of a mixture of these with bisphenol A, bisphenol F, and the like. These bisphenols can be glycidylated with epichlorohydrin or β-methylepichlorohydrin. In particular, a glycidyl ether of an alkylene oxide adduct of bisphenol A is preferred.

The Tg of these polyester resins and epoxy resins is preferably from 58 to 75 ° C.

The toner of the present invention can use resins other than polyester resins and epoxy resins. As the other resin used in the present invention, a conventionally known resin is used. For example, styrene, poly-α-stillstyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer, styrene -Styrene such as maleic acid copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethyl acrylate copolymer, styrene-acrylonitrile-acrylic acid ester copolymer Resin (mono- or copolymer containing styrene or styrene substituent), vinyl chloride resin, rosin-modified maleic resin, phenol resin, polyethylene resin, polypropylene resin, petroleum resin, polyurethane resin, ketone resin, ethylene-ethyl Acrylate copolymer, xylene Resins, polyvinyl butyrate resins, and the like can be mentioned. These resins may be used in combination with a polyester resin or an epoxy resin, or may be used alone. Also, two or more kinds may be used in combination.

The method for producing these resins is not particularly limited, and any of bulk polymerization, solution polymerization, emulsion polymerization and suspension polymerization can be used.

As the colorant used in the present invention, all pigments and dyes conventionally used as colorants for toner are applied. Specifically, carbon black,
Lamp black, iron black, ultramarine, nigrosine dye, aniline blue, calco oil blue, Dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, phthalocyanine green, hansa yellow, rhodamine 6C lake, chrome yellow, quinacridone, benzidine yellow, malachite green,
Malachite green hexalate, oil black, azo oil black, rose bengal, monoazo dyes, disazo dyes, trisazo dyes, and the like.

The amount of the colorant used is generally 0.1 to 50 parts by weight based on 100 parts by weight of the binder resin.

In the toner of the present invention, it is effective to add a polarity controlling agent in order to control the polarity.
Examples of the polarity control agent in this case include a nigrosine dye, a quaternary ammonium salt, an amino group-containing polymer, a metal-containing azo dye, a complex compound of salicylic acid, and a phenol compound, among which the color tone is not affected. A quaternary ammonium salt amino group-containing polymer and a complex compound of salicylic acid are useful.

In the present invention, the amount of the charge control agent used depends on the type of the binder resin, the presence or absence of additives used as necessary,
It is determined by the toner manufacturing method including the dispersion method, and is not limited to a specific one. However, it is preferably used in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin. . More preferably, the range is 2 to 5 parts by weight. If the amount is less than 0.1 part by weight, the negative charge of the toner is insufficient, which is not practical. If the amount is more than 10 parts by weight, the chargeability of the toner is too large, and the electrostatic attraction between the toner and the carrier or the charging member is increased, so that the fluidity of the developer is reduced and the image density is reduced.

As other additives, for example, fatty acid metal salts (aene stearate, aluminum stearate, etc.), other metal oxides (aluminum oxide, tin oxide, antimony oxide, etc.), fluoropolymers and the like may be contained. good.

In the present invention, the toner may be fixed in a contact fixing system in which the toner is directly contacted with a heat roller or the like, or may be used in a non-contact fixing system by, for example, flash fixing or ultraviolet irradiation. . When a non-contact fixing method using ultraviolet irradiation is employed, it is desirable to use an ultraviolet curable resin as a part of the binder resin of the toner base particles.

In the present invention, the toner may be used as a developer alone to develop an electrostatic latent image into a visible image by a so-called one-component developing method. Alternatively, a two-component developer obtained by mixing a toner and a carrier may be used. The latent image may be developed by a two-component developing method for visualizing the electrostatic latent image. As a carrier used when the toner of the present invention is used as a two-component dry toner, glass,
A powder containing iron, ferrite, nickel, zircon, silica or the like as a main component and having a particle size of about 30 to 1000 μm is used. Styrene-acrylic resin using the powder as a core material,
A resin coated with a silicon-based resin, a polyamide-based resin, a polyvinylidene fluoride-based resin, or the like is more preferable because the surface deterioration due to the toner is small and the life of the developer can be extended. In general, a suitable mixing ratio of the carrier and the toner is about 0.5 to 6.0 parts by weight of the toner per 100 parts by weight of the carrier.

[0043]

Next, the present invention will be described more specifically with reference to examples. In the embodiment of the present invention, recording paper is used as a recording medium, but a recording medium such as an intermediate transfer belt and an OHP sheet can also be used. Parts here are by weight. Also, although the examples take up a two-component developer,
Of course, the present invention is not limited to this, and can be used as a one-component developer.

<< Toner Production Example 1 >> (Black Toner) 1200 parts of water 200 parts of phthalocyanine green water-containing cake (solid content 30%) 200 parts 540 parts of carbon black (MA60, manufactured by Mitsubishi Chemical Corporation) are thoroughly stirred with a flasher. In addition, epoxy polyol resin (Mn: 3800, Mw / Mn: 3.9, T
g: 59 ° C.), kneading at 150 ° C. for 30 minutes, kneading at 150 ° C. for 30 minutes, adding 1000 parts of xylene, kneading for another hour, removing water and xylene, rolling, cooling and pulverizing with a pulperizer to obtain a master batch pigment. . Subsequently, a material consisting of 100 parts of an epoxy polyol resin (Mn: 3800, Mw / Mn: 3.9, Tg: 59 ° C.) 8 parts of the above master batch pigment 2 parts of a zinc salicylate derivative (Bontron E84, manufactured by Orient Chemical Co., Ltd.) After mixing with a mixer, the mixture was melt-kneaded with a two-roll mill, and the kneaded product was rolled and cooled. Thereafter, pulverization and classification were performed to obtain toner base particles having a volume average particle size of 8.0 μm.
Further, 0.1 wt% of hydrophobic rutile type titanium oxide fine powder (MT150A, average particle size 0.01 μm, manufactured by Teica) was added to the toner base particles, and hydrophobic silica fine powder (H20) was used.
00, average particle size 0.02 μm, Hoechst) 0.2 wt.
% And mixed with a mixer to obtain a black toner.

(Magenta Toner) 600 parts of water 1200 parts of Pigment Red 57 water-containing cake (solid content 50%) is thoroughly stirred with a flasher. In addition, epoxy polyol resin (Mn: 3800, Mw / Mn: 3.9, T
g: 59 ° C.), kneading at 150 ° C. for 30 minutes, kneading at 150 ° C. for 30 minutes, adding 1000 parts of xylene, kneading for 1 hour, removing water and xylene, rolling and cooling, pulverizing with a pulperizer, and adding 2 parts with a three-roll mill. Pass to obtain a masterbatch pigment. Subsequently, a material consisting of 100 parts of an epoxy polyol resin (Mn: 3800, Mw / Mn: 3.9, Tg: 59 ° C.) 8 parts of the above master batch pigment 2 parts of a zinc salicylate derivative (Bontron E84, manufactured by Orient Chemical Co., Ltd.) After mixing with a mixer, the mixture was melt-kneaded with a two-roll mill, and the kneaded product was rolled and cooled. Thereafter, pulverization and classification were performed to obtain toner base particles having a volume average particle size of 8.0 μm.
Further, 0.15 wt. Of hydrophobic rutile-type titanium oxide fine powder (MT150A, manufactured by Teica) was added to the toner base particles.
%, Hydrophobic silica fine powder (H2000, manufactured by Hoechst)
Was added thereto and mixed with a mixer to obtain a magenta toner.

(Cyan Toner) 600 parts of water 1200 parts of Pigment Blue 15: 3 water-containing cake (solid content 50%) are thoroughly stirred with a flasher. In addition, epoxy polyol resin (Mn: 3800, Mw / Mn: 3.9, T
g: 59 ° C.), kneading at 150 ° C. for 30 minutes, kneading at 150 ° C. for 30 minutes, adding 1000 parts of xylene, kneading for 1 hour, removing water and xylene, rolling and cooling, pulverizing with a pulperizer, and adding 2 parts with a three-roll mill. Pass to obtain a masterbatch pigment. Subsequently, 100 parts of an epoxy polyol resin (Mn: 3800, Mw / Mn: 3.9, Tg: 59 ° C., melt viscosity at 140 ° C .: 75 mP · sec) 5 parts of the above master batch pigment zinc salicylate derivative (Bontron E84, A mixture of 2 parts (Orient Chemical Co., Ltd.) was mixed with a mixer, melt-kneaded with a two-roll mill, and the kneaded product was rolled and cooled. Thereafter, pulverization and classification were performed to obtain toner base particles having a volume average particle size of 8.0 μm.
Further, 0.2 wt% of hydrophobic rutile type titanium oxide fine powder (MT150A, manufactured by Teica) was added to the toner base particles.
%, Hydrophobic silica fine powder (H2000, manufactured by Hoechst)
Was added and mixed with a mixer to obtain a cyan toner.

(Yellow Toner) 600 parts of water 1200 parts of a pigment yellow 17 water-containing cake (50% of solid content) are thoroughly stirred with a flasher. In addition, epoxy polyol resin (Mn: 3800, Mw / Mn: 3.9, T
g: 59 ° C.), kneading at 150 ° C. for 30 minutes, kneading at 150 ° C. for 30 minutes, adding 1000 parts of xylene, kneading for 1 hour, removing water and xylene, rolling and cooling, pulverizing with a pulperizer, and adding 2 parts with a three-roll mill. Pass to obtain a masterbatch pigment. Subsequently, a material consisting of 100 parts of an epoxy polyol resin (Mn: 3800, Mw / Mn: 3.9, Tg: 59 ° C.) 8 parts of the above master batch pigment 2 parts of a zinc salicylate derivative (Bontron E84, manufactured by Orient Chemical Co., Ltd.) After mixing with a mixer, the mixture was melt-kneaded with a two-roll mill, and the kneaded product was rolled and cooled. Thereafter, pulverization and classification were performed to obtain toner base particles having a volume average particle size of 8.0 μm.
Further, 0.2 wt% of hydrophobic rutile type titanium oxide fine powder (MT150A, manufactured by Teica) was added to the toner base particles.
%, Hydrophobic silica fine powder (H2000, manufactured by Hoechst)
Was added and mixed with a mixer to obtain a yellow toner.

<< Toner Production Example 2 >> A toner was produced in exactly the same manner as in Toner Production Example 1 except that the addition amounts of the hydrophobic rutile-type titanium oxide fine powder and the hydrophobic silica fine powder were as shown in Table 1 below.

[Table 1]

<< Toner Production Example 3 >> A toner was produced in exactly the same manner as in Toner Production Example 1 except that the amounts of the hydrophobic rutile-type titanium oxide fine powder and the hydrophobic silica fine powder were changed as shown in Table 2 below.

[Table 2]

<< Toner Production Example 4 >> A toner was produced in exactly the same manner as in Toner Production Example 1, except that the addition amounts of the hydrophobic rutile-type titanium oxide fine powder and the hydrophobic silica fine powder were as shown in Table 3 below.

[Table 3]

<< Toner Production Example 5 >> Produced in exactly the same manner as in Toner Production Example 1 except that hydrophobic anatase-type titanium oxide fine powder (STT-30, titanium industry) was used instead of hydrophobic rutile-type titanium oxide fine powder. did.

<< Carrier Production Example 1 >> Silicon resin solution (manufactured by Shin-Etsu Chemical Co., Ltd., KR50) 100 parts Carbon black (manufactured by Cabot Corporation, BP2000) 3 parts Toluene 100 parts The above formulation is dispersed by a homomixer for 30 minutes to form a coating layer. The liquid was adjusted. This coating layer forming solution was used to obtain a carrier A in which a coating layer was formed on the surface of 1,000 parts of spherical ferrite having an average particle size of 50 μm using a fluidized bed type coating apparatus.

Example 1 1.7 kg of the carrier A and 70 g of the toner of Production Example 1 were placed in a ball mill and stirred for 10 minutes to obtain a two-component developer. The obtained developer is placed in a commercially available electrophotographic copying machine (IBM 3170 digital full-color printer) to produce an image, and the transfer dust of the overlapping portion of four colors is best.
The worst was evaluated as 1 and evaluated on a 5-point scale. Further, the charge amount of the toner in the developing section was measured by a blow-off method. further,
A running test of 50,000 sheets of A4 size was performed, and the yield was calculated. Table 4 shows the results.

Example 2 1.7 kg of the carrier A and 70 g of the toner of Production Example 2 were placed in a ball mill and stirred for 10 minutes to obtain a two-component developer. The obtained developer was put into an IBM 3170 digital full-color printer to produce an image, and the transfer dust of the overlapping portion of four colors was evaluated on a five-point scale. Further, the charge amount of the toner in the developing section was measured by a blow-off method. Further, a running test was performed on 50,000 sheets of A4 size, and the yield was calculated. Table 4 shows the results.

Example 3 1.7 kg of the carrier A and 70 g of the toner of Production Example 3 were placed in a ball mill and stirred for 10 minutes to obtain a two-component developer. The obtained developer was put into an IBM 3170 digital full-color printer to produce an image, and the transfer dust of the overlapping portion of four colors was evaluated on a five-point scale. Further, the charge amount of the toner in the developing section was measured by a blow-off method. Further, a running test was performed on 50,000 sheets of A4 size, and the yield was calculated. Table 4 shows the results.

Example 4 1.7 kg of the carrier A and 70 g of the toner of Production Example 4 were placed in a ball mill and stirred for 10 minutes to obtain a two-component developer. The obtained developer was put into an IBM 3170 digital full-color printer to produce an image, and the transfer dust of the overlapping portion of four colors was evaluated on a five-point scale. Further, the charge amount of the toner in the developing section was measured by a blow-off method. Further, a running test was performed on 50,000 sheets of A4 size, and the yield was calculated. Table 4 shows the results.

Comparative Example 1 1.7 kg of the carrier A and 70 g of the toner of Production Example 5 were placed in a ball mill and stirred for 10 minutes to obtain a two-component developer. The obtained developer was put into an IBM 3170 digital full-color printer to produce an image, and the transfer dust of the overlapping portion of four colors was evaluated on a five-point scale. Further, the charge amount of the toner in the developing section was measured by a blow-off method. Further, a running test was performed on 50,000 sheets of A4 size, and the yield was calculated. Table 4 shows the results.

[0058]

[Table 4]

[0059]

As is clear from the description of the embodiments, according to the present invention, the transfer is achieved by using a toner in which hydrophobic rutile-type titanium oxide fine powder and hydrophobic silica fine powder are externally added to toner base particles. An image free of dust can be obtained, a toner charge amount having no problem in image density and toner scattering can be obtained, and an extremely excellent effect of high yield can be exhibited.

Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat II (Reference) G03G 9/08 375 9/10 352 F term (Reference) 2H005 AA01 AA06 AA08 AA21 BA06 CA07 CA12 CA21 CA25 CA28 CB07 CB13 DA01 DA02 DA03 EA05 EA07 FA01

Claims (9)

[Claims] 1. An electrostatic image developing toner in which an external additive is added to toner base particles containing at least a binder resin, a colorant, and a charge control agent as main components, wherein the external additive has an average particle size. A toner for developing an electrostatic charge image, comprising a combination of 0.005-0.2 μm hydrophobic rutile-type titanium oxide fine powder and hydrophobic silica fine powder having an average particle diameter of 0.005-0.2 μm. 2. The toner according to claim 1, wherein the ratio of the weight (Wt) of the hydrophobic rutile type titanium oxide fine powder to the weight (Ws) of the hydrophobic silica fine powder in the toner is 0.5 ≦ W.
A black toner for developing electrostatic images, wherein t / Ws ≦ 1.3. 3. The toner according to claim 1, wherein the ratio of the weight (Wt) of the hydrophobic rutile-type titanium oxide fine powder to the weight (Ws) of the hydrophobic silica fine powder in the toner is 0.7 ≦ W.
A magenta toner for developing an electrostatic image, wherein t / Ws ≦ 1.5. 4. The toner according to claim 1, wherein the ratio of the weight (Wt) of the hydrophobic rutile-type titanium oxide fine powder to the weight (Ws) of the hydrophobic silica fine powder in the toner is 0.8 ≦ W.
A cyan toner for developing an electrostatic image, wherein t / Ws ≦ 1.6. 5. The toner according to claim 1, wherein the ratio of the weight (Wt) of the hydrophobic rutile type titanium oxide fine powder to the weight (Ws) of the hydrophobic silica fine powder in the toner is 0.9 ≦ W.
A yellow toner for developing an electrostatic image, wherein t / Ws ≦ 1.8. 6. The toner for developing an electrostatic image according to claim 1, wherein the charge control agent is a complex compound of a quaternary ammonium salt amino group-containing polymer and salicylic acid. 7. The toner for developing an electrostatic image according to claim 1, wherein the binder resin is an epoxy resin. 8. The toner according to claim 2, wherein the hydrophobic rutile-type titanium oxide fine powder and the hydrophobic silica fine powder are combined in a total amount of 0.1 to 100 parts by weight of the toner base particles. A non-contact fixing type toner for developing an electrostatic image, wherein the toner is used in an amount of from 2.0 to 2.0 parts by weight. 9. A two-component developer comprising the toner according to claim 1 and a carrier which has been subjected to a silicon coating treatment.