JPH08262784A - Toner for developing electrostatic charge image and its production - Google Patents

Abstract

PURPOSE: To form an image free from image fog without scattering a toner. CONSTITUTION: In this toner consisting of colored particles consisting essentially of a resin, a colorant and a releasing agent and inorg. fine particles, the amt. of the releasing agent existing on the surfaces of the colored particles is 0.1-0.3, the domain diameter of the releasing agent in the colored particles is 0.1-1.0μm and the inorg. fine particles are two or more kinds of inorg. fine particles (A), (B) satisfying the inequalities 10<Qa-Qb<300 and 0<Qb<50 [where Qa is the quantity (μC/g) of electric charges of the inorg. fine particles A and Qb is the quantity (μC/g) of electric charges of the inorg. fine particles B].

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic charge image developing toner used in an image forming method such as electrophotography and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, an electrostatic image developing toner is manufactured, for example, as follows. First, the binder resin and the colorant,
Then, if necessary, a release agent, a charge control agent, a magnetic material, and other auxiliary agents are added. After premixing this blend, it is melt-kneaded. The obtained kneaded product is cooled, then pulverized and classified to obtain colored particles. Further, the obtained colored particles are blended with inorganic fine particles and, if necessary, other additives. A toner is obtained by externally mixing this compound.

The purpose of externally adding the inorganic fine particles is to improve the fluidity of the toner and also to control the charging property. On the surface of the colored particles, a binder resin, a coloring agent, a releasing agent, and a charging agent are charged. Those having different compositions such as a control agent and different charging properties are exposed, and selectively adhere to a portion which is easily electrostatically adhered when externally mixing inorganic fine particles. Therefore, weakly charged toner and reverse polarity toner are generated due to non-uniform charging property, which causes image fogging and toner scattering. In particular, the colored particles immediately after the kneading, pulverizing and classifying steps are very dry and in an electrostatically active state. Therefore, image fogging and toner scattering are likely to occur due to the non-uniform charging property described above.

Conventionally, a technique for defining the surface abundance of a compound having releasability, such as polypropylene or polystyrene, and the domain diameter of these is known (for example, JP-A-3-243956 and JP-A-3-264961). Japanese Patent Laid-Open No. 3-296067
No. 5-45925). Also disclosed therein are methods for suppressing pulverization of toner particles, filming, spent, and sticking to a blade.

As a positively chargeable toner, there is known a toner containing inorganic fine particles treated with an ammonium salt-modified polysiloxane or treated with a nitrogen-containing coupling agent (JP-A-2-110473 and JP-A-2-110473). 2-110474 etc.). However, when this technique is applied to a toner containing a release agent, the effect of imparting a positive chargeability is high, but the negative chargeability of the release agent (so-called polyolefins) present on the toner surface causes Selective adhesion to the part occurs, the surface of the toner becomes non-uniform, and in long-term use, the burial of the inorganic fine particles on the surface of the release agent is promoted, and the durability cannot be maintained. As a result, problems such as image fog and toner scattering occur.

Further, two kinds of hydrophobicized inorganic fine particles having different polarities are used to prevent an increase or decrease of the charge amount by a canceling effect, thereby avoiding blocking or attenuation of the toner charge amount (Japanese Patent Laid-Open Publication No. HEI5- No. 74818), and silica particles and titania particles are used to prevent fogging due to a reverse polarity toner (Japanese Patent Application Laid-Open No. 2-43564). However, even in these cases, selective adhesion of the external additive to the release agent is not possible. Since it has not been sufficiently improved, image fog and toner scattering have not been sufficiently improved as in the above-mentioned technique.

[0007]

By uniformly depositing the inorganic fine particles on the surface of the colored particles and preventing the generation of the weakly charged toner and the reverse polarity toner, image fog and toner scattering are reduced, and stable for a long period of time. Get charge.

[0008]

The present invention has been proposed to solve the above problems. That is, the inventors of the present invention, in the above-mentioned kneading and pulverizing steps, to make the chargeability of the surface of the colored particles uniform, specifically, to make the dispersion of the release agent forming the domains in the resin uniform. In order to control the surface properties of the particles and to achieve uniform adhesion of the inorganic fine particles to the surface, it is possible to selectively adhere to the surface of the colored particles by adding two or more kinds of inorganic fine particles having different charge amounts. It was found that prevention is important for increasing the uniformity of the external additive on the toner surface and achieving the task,
The invention has been completed.

That is, the object of the present invention is to provide a toner comprising at least colored particles comprising a resin, a colorant and a release agent and inorganic fine particles, wherein the amount of the release agent present on the surface of the colored particles is 0.1 to 0. .3, and the release agent domain diameter in the colored particles is in the range of 0.1 to 1.0 μm,
Toner characterized in that the charge amount of the inorganic fine particles is composed of at least two kinds of inorganic fine particles (A, B) satisfying the following relational expression: 10 <Qa-Qb <3000 <Qb <50 Qa: Inorganic fine particles ( A) Charge amount (μC / g) Qb: Achieved by the charge amount (μC / g) of the inorganic fine particles (B).

In order to control the release agent domain diameter, the average filling degree of the kneaded material in the kneading zone in the kneading machine in the kneading step is
It is in the range of 240 to 400 (kg / m ³ ), and the fluctuation range is controlled to be ± 10% or less so that the additives in the kneaded material, particularly the release agent, are uniformly dispersed. Further, the amount of the surface release agent can be achieved by controlling the amount returned to the crushing process in the closed circuit crushing system. By uniformly dispersing the negatively-charged release agent in the colored particles, the negatively-charged surface of the colored particles is made uniform.

If the release agent domain diameter is less than 0.1 μm, the inorganic fine particles are less likely to adhere, and if it exceeds 1.0 μm, the release agent is insufficiently dispersed.

The release agent surface abundance is, for example, a resin containing oxygen such as a styrene-acrylic polymer is used, and the release agent is a hydrocarbon compound such as a low molecular weight polyolefin. In some cases, it can be defined by the amount of oxygen obtained by surface analysis of the toner surface by ESCA. The release agent surface abundance is the reciprocal of the amount of oxygen obtained by ESCA.

The surface in the present invention is defined as from the outermost surface to a depth of about 0.1 μm. That is, the effective depth from the surface that can contribute to the charging property of the toner surface is about 0.
It is defined because it is up to 1 μm. Although the depth as a measurement value when measuring the existence ratio of the surface varies depending on the measuring method, in ESCA, the measuring depth can be controlled by a method such as surface etching.

As the ESCA measuring instrument, there is the model 5400 series manufactured by ULVAC-PHI, Inc., and the surface abundance can be calculated from the following formula as described above.

{[C] + [O] + [N]} / [O] where [C], [O], and [N] are carbon, oxygen, and nitrogen present on the surface, as measured by ESCA. The atomic number% is shown.

If the amount of the release agent on the surface is less than 0.1, it is difficult for the inorganic fine particles to adhere, and if it exceeds 0.3, the negative chargeability of the release agent poses a problem, and the chargeability becomes weak, resulting in a weak charge. The generation of toner and reverse polarity toner causes problems such as image fogging and toner scattering.

The charge amount of the inorganic fine particles is determined by the method described later. The difference in charge amount between the inorganic fine particles (A) and (B) is 10
To 300 μc / g is preferable, and more preferably 20 to 25
It is 0 μc / g. When this difference is 10 μC / g or less, it is difficult to prevent the selective adhesion of the inorganic fine particles (A) having a high charge amount to the surface of the colored particles because the difference in the charge amount is small. When it is 300 μC / g or more, electrostatic adhesion between the inorganic fine particles occurs, and the effect of the plurality of inorganic fine particles cannot be exhibited. Further, the charge amount of the inorganic fine particles (B) is preferably small in positive chargeability, and is less than 50 μC / g. It is more preferably 2 to 40 μC / g. If this charge amount is too large, it becomes difficult to prevent the selective adhesion of the inorganic fine particles (A) having a high charge amount. If the toner has a negative charging property, the charging property of the toner will be significantly reduced.

The release agent domain diameter, the release agent surface abundance, and the charge amount can be determined by the methods described in Examples below.

[0019]

As the raw material for the toner used in the present invention, all known materials can be used. First, as the binder resin, for example, polyester resin, styrene-alkyl acrylate resin, styrene-alkyl methacrylate resin, styrene-butadiene resin, styrene-acrylonitrile resin, styrene-acryl-ester resin, styrene-acryl- Crystalline ester graft resin, urethane resin, epoxy resin, silicone resin, vinyl chloride resin,
Examples thereof include amide resin, vinyl butyral resin, rosin resin, modified rosin resin, phenol resin, and xylene resin.

As the colorant, for example, carbon black,
Examples include chrome yellow, DuPont oil red, quinoline yellow, and phthalocyanine blue.

When used as a one-component developer (magnetic toner), so-called magnetic powder may be used as a colorant. As the magnetic powder, any magnetic material that has been conventionally used can be used. The magnetic substance is a ferromagnetic element or an alloy or compound containing them, and a compound such as magnetite, maghemite, or ferrite, or iron,
Examples include metals such as cobalt, nickel, manganese, and alloys thereof.

Although the content of the magnetic powder varies depending on the developing method, it can be added to the toner in an amount of 15 to 80 wt%. More preferably, it is 25 to 65 wt%. further,
The particle diameter of this magnetic powder is 0.0 in terms of number average primary particle diameter.
1 to 1 μm is preferable, and 0.1 to 0.
5 μm. In addition, this particle size shows the value measured by the transmission electron microscope.

As the charge control agent, a nigrosine dye, 4
An organic salt or complex containing a secondary ammonium salt compound, an alkylpyridinium compound and a divalent or higher valent metal can be used.

Examples of the releasing agent include low molecular weight polyethylene having a number average molecular weight (the number average molecular weight is a polystyrene molecular weight conversion value in high temperature GPC) of 1500 to 8000, low molecular weight polypropylene and low molecular weight polyethylene.
Polyolefin wax such as polypropylene copolymer and high melting point paraffin wax such as microwax and Fischer-Tropsch wax can be used.

The above-mentioned raw materials are appropriately mixed, and colored particles are obtained through the steps of mixing, kneading, cooling, pulverizing and classifying. At this time, the colored particles have been dried by the heat applied by kneading or the like and are in a state of being easily charged.

Next, inorganic fine particles and, if necessary, other substances are mixed as an external additive. Examples of the inorganic fine particles include silica, barium titanate, magnesium titanate, calcium titanate, strontium titanate, and oxidation. Examples thereof include zinc, cerium oxide, antimony trioxide, zirconium oxide, silicon carbide and silicon nitride. These may be hydrophobized or non-hydrophobicized. The average particle diameter is the primary average particle diameter,
005 μm to 0.5 μm is preferable, and particularly 0.00
It is preferably 6 μm to 0.3 μm. The average particle diameter of the inorganic fine particles means the primary average particle diameter measured by image analysis by observing with a scanning electron microscope.

In order to obtain the inorganic fine particles in the preferred range, the amount of charge can be adjusted by surface-treating with a surface-treating agent. Such surface treatment agents include titanium coupling agents such as tetrabutyl titanate, tetraoctyl titanate, isopropyl triisostearoyl titanate, isopropyl tridecylbenzene sulfonyl titanate, bis (dioctyl pyrophosphate).
Oxyacetate titanate and the like. Further, as the silane coupling agent, γ- (2-aminoethyl)
Aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, γ-
(2-Aminoethyl) aminopropyltrimethoxysilane hydrochloride, γ-methacryloxypropyltrimethoxysilane, N-β- (N-vinylbenzylaminoethyl) γ
-Aminopropyltrimethoxysilane hydrochloride, dichlorodimethylsilane, hexamethyldisilazane, methyltrimethoxysilane, butyltrimethoxysilane, isobutyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, dodecyltrisilane Examples thereof include methoxysilane, phenyltrimethoxysilane, o-methylphenyltrimethoxysilane, p-methylphenyltrimethoxysilane and the like.

Further, organopolysiloxanes such as polydimethylsiloxane, polyoctyl, methylsiloxane, polydiphenylsiloxane, polymethylphenyl and siloxane, and amino-modified silicone oil can also be used.

Examples of the fatty acid and its metal salt include undecyl acid, lauric acid, tridecyl acid, dodecyl acid, myristic acid, palmitic acid, pentadecyl acid, stearic acid, heptadecyl acid, arachidic acid, montanic acid, oleic acid, linoleic acid, Examples include long-chain fatty acids such as arachidonic acid, and their metal salts include zinc, iron, magnesium,
Examples thereof include salts with metals such as aluminum, calcium, sodium and lithium.

Other external additives include lubricants such as zinc stearate and polyvinylidene fluoride.

In order to adjust the inorganic fine particles (A) and (B) having different charge amounts, it can be obtained by adjusting the above-mentioned surface treatment agent.

The total proportion of the inorganic fine particles (A) and (B) is preferably 0.01 to 10% by weight, more preferably 0.05 to 5% by weight based on the toner. The ratio of (B) to the total amount of the inorganic fine particles (A) and (B) is preferably 1 to 50 wt%. When the total proportion of these inorganic fine particles is too large, the inorganic fine particles are liberated and adhere to the carrier, which causes a problem of a decrease in charge amount. On the other hand, when the total proportion is too small, the effect of adding the inorganic fine particles is not exerted such that an appropriate amount of charge and sufficient fluidity cannot be obtained. Further, the ratio of the inorganic fine particles (B) is 1 wt with respect to the total amount of the inorganic fine particles (A) and (B).
If it is less than 50%, it becomes difficult to prevent the selective adhesion of the inorganic fine particles (A), and if it exceeds 50% by weight, electrostatic adhesion between the inorganic fine particles occurs and the effect of the plurality of inorganic fine particles cannot be exhibited. .

The toner of the present invention is mixed with a carrier to prepare a toner.
It may be used as a component developer or may be used as a toner alone as a one-component developer.

As a carrier constituting the two-component developer, a conventionally known carrier can be used. Ferromagnetic metals such as iron, nickel and cobalt, alloys containing these metals, ferromagnetism such as ferrite and magnetite. A carrier obtained by coating particles of a metal compound with a fluororesin, a silicone resin, or the like, and a magnetic substance-dispersed carrier in which magnetic fine particles are dispersed in a polyester resin or a polyethylene resin can be preferably used. The volume average particle diameter of the carrier is preferably in the range of 20 to 200 μm, particularly 30 to 1
The range of 50 μm is preferable. In addition, the volume average particle diameter is a laser diffraction type particle size distribution measuring apparatus "Heros" equipped with a wet disperser.
(HELOS) "(manufactured by SYMPATEC).

[0035]

The present invention will be described in detail below with reference to examples, but the embodiments of the present invention are not limited thereto.

(Production of Inorganic Fine Particles) Inorganic fine particles Charge amount μC / g a 6- (2-aminoethyl) aminopropyl methyldimethoxysilane surface-treated 378 1-order average particle diameter 0.006 μm Silica b γ- (2 -Aminoethyl) aminopropyltrimethoxysilane 150 surface-treated with hydrochloride and dichlorodimethylsilane 150 silica with a primary average particle size of 0.008 μm c surface-treated with amino-modified silicone oil 145 silica with a primary average particle size of 0.008 μm d Surface-treated with polyoctylmethylsiloxane 60 Silica with 1st-order average particle size 0.05 μm e Surface-treated with decyltrimethoxysilane 28 Titanium oxide with 1st-order average particle size 0.10 μm f Surface-treated with octyltrimethoxysilane 20 Titanium oxide having a primary average particle size of 0.05 μm g Surface-treated with dimethylpolysiloxane 10 Titanium oxide having a 1st-order average particle diameter of 0.05 μm h Surface-treated with hexamethyldisilazane −-30 Titanium oxide having a 1st-order average particle diameter of 0.08 μm Here, the charge amount of the inorganic fine particles Was determined by the following method. 0.2 g of inorganic fine particles and 20 g of a ferrite core (DFC-200F manufactured by Dowa Iron Powder Industry Co., Ltd.) having a volume average particle diameter of 60 μm were put in a 20 cc glass bottle and shaken in an environment of 20 ° C. and 50% RH for 20 minutes. (Shaker: YS manufactured by Yayoi Co., Ltd.
-LD) and a blow-off powder charge amount measuring device (TB-200 manufactured by Toshiba Chemical Co., Ltd.).

(Example of Two-Component Developer) Binder Resin Styrene-Acrylic Resin 100 parts by weight Coloring agent carbon black 10 parts by weight Release agent Low molecular weight polypropylene 3 parts by weight (number average molecular weight = 3000) The number average molecular weight is , Obtained by the following method.

That is, GPC-150C (WATER
(Manufactured by S Co., Ltd.), and as a column, SHODEX HT-8
06, o-dichlorobenzene with 0.1% ionol added as solvent, temperature = 135 ° C., flow rate = 1
It is measured under the condition of ml / min. The calibration of the molecular weight is a styrene-equivalent molecular weight.

The above components were mixed, kneaded, pulverized and classified to obtain colored particles having a volume average particle diameter of 8.5 μm. Two kinds of inorganic fine particles a to h were combined with the colored particles and externally added to obtain a toner. Release agent domain diameter of colored particles, release agent surface abundance, addition amount of two kinds of inorganic fine particles, and Qa
-Qb and Qb are shown in Table 1 below.

The amount of the release agent present on the surface and the domain diameter were determined by the following methods.

Amount of release agent on the surface The ESCA measuring instrument is manufactured by ULVAC-PHI.
There are model 5400 series etc. In the present invention, the measurement conditions for ESCA analysis were carried out as follows.

Measuring device: PHI manufactured by Perkin Elmer
Model 560 ESCA / SAM Measurement conditions: X-ray output 15 kv, 26.7 mA Sample preparation: Toner is sprinkled on double-sided tape and fixed on the sample table for measurement. The peaks of carbon C1S oxygen O1S nitrogen N1S are used for quantitative calculation. Each amount was calculated from the area of the peak. Using these peak areas, the intensity ratio was corrected by the sensitivity coefficient as the intensity correction by each element.

The sensitivity coefficient is "Hand" manufactured by Perkin Elmer.
"Book of Xray PHOTOELECTRON SPECTROS COPY". The amount of oxygen existing on the surface was calculated from the element ratio (AC) obtained as described above and expressed as the reciprocal.

Domain size Toner is embedded in resin and is about 0.20μ with a microtome.
Create m-thick sections. This section was photographed with a transmission electron microscope at a negative magnification of 280 times and stretched to produce a 1200 times photograph. This is an image analysis device (SP
ICCA: Japan Avionics Co., Ltd.) analyzes the image and measures the domain diameter. Here, the domain diameter was measured by the number average diameter.

[0045]

[Table 1]

The toners obtained in Examples 1 to 6 and Comparative Examples 1 to 8 were mixed with a styrene-acrylic resin-coated copper-zinc ferrite carrier having a volume average particle size of about 60 μm to obtain a toner concentration of 5%. A two-component developer was obtained.

Using a modified electronic copying machine (U-BIX 3035 made by Konica) equipped with a negatively chargeable organic photoreceptor,
The developing conditions are a photoreceptor surface potential of 600 V, a DC bias potential of 150 V, and a developing gap 50 between the developing sleeve and the photoreceptor.
The actual copying test was conducted over 100,000 copies in an environment of 0 μm, 30 ° C. and 80% RH.

(Example of one-component developer) Binder resin Styrene-acrylic resin 100 parts by weight Coloring agent Magnetic powder (first-order average particle size = 0.2 μm) 60 parts by weight Release agent Low molecular weight polypropylene 3 parts by weight (number) Average molecular weight = 3500) The number average molecular weight, the amount of the release agent on the surface, and the like were determined by the same method as for the two-component developer.

The above components were mixed, kneaded, pulverized and classified to obtain colored particles having a volume average particle diameter of 11.0 μm. Two or more of the following inorganic fine particles a to h are combined with the colored particles and subjected to an external addition treatment, and Examples 7 to 12 and Comparative Examples 9 to 16 are performed.
Magnetic toner of Table 2 below shows the release agent domain diameter of the colored particles, the surface abundance, the addition amounts of the two kinds of inorganic fine particles, and the like.

[0050]

[Table 2]

An electronic copying machine (manufactured by U-BIX 3035 Konica Corp.) equipped with a negatively chargeable organic photoconductor was remodeled and the developing condition was changed to the one-component developing condition. Photoconductor surface potential 600
V, DC bias potential of 150 V, development gap between developing sleeve and photoconductor of 200 μm, developer layer = 220 μm, and an actual copying test was conducted for 100,000 copies in an environment of 30 ° C. and 80% RH.

(Evaluation Criteria) a. An image fog Sakuradensitometer (manufactured by Konica Corporation) was used to measure the relative density of the white background portion of the copy image corresponding to the white background portion (reflection density 0.000) of the transfer paper.

Less than 0.010 (no practical problem) 0.010 or more (no practical problem) b. Toner scattering Place a blank sheet of paper under the development area, attach the scattered toner, fix the blank sheet under the same fixing conditions as the same evaluation machine, and measure the density with a Sakura densitometer. The relative concentration corresponding to 0.00) was measured.

[0054] The above evaluation results are shown in Table 3 for the two-component developer and Table 4 for the one-component developer.

[0055]

[Table 3]

[0056]

[Table 4]

According to the above results, Examples 1 to 1 in the present invention
6 and Examples 7 to 12 show good characteristics in both fogging and toner scattering, while it is understood that the comparative examples other than the present invention have problems in both performances.

[0058]

EFFECTS OF THE INVENTION According to the present invention, the adhesion of the inorganic fine particles to the surface of the colored particles is made uniform, and the weak charge and the generation of the opposite polarity toner are prevented, so that the image fog and the toner scattering are reduced and the toner is stable for a long period of time. The chargeability can be obtained.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuji Marukawa 2970 Ishikawa-cho, Hachioji-shi, Tokyo Konica Stock Company

Claims (2)

[Claims] 1. A toner for developing an electrostatic image comprising at least colored particles comprising a resin, a colorant and a release agent and inorganic fine particles, wherein the amount of the release agent on the surface of the colored particles is 0.1 to 0. .3, the release agent domain diameter in the colored particles is in the range of 0.1 to 1.0 μm, and the amount of charge of the inorganic fine particles satisfies at least the following relational expression. A toner for developing an electrostatic charge image, which comprises B). 10 <Qa-Qb <3000 0 <Qb <50 However, Qa: charge amount of inorganic fine particles (A) (μC / g) Qb: charge amount of inorganic fine particles (B) (μC / g) 2. In the method for producing an electrostatic charge image developing toner comprising at least colored particles comprising a resin, a colorant and a release agent and inorganic fine particles, the amount of the release agent on the surface of the release agent is 0.1. To 0.3, the release agent domain diameter in the colored particles is in the range of 0.1 to 1.0 μm, and the charge amount of the inorganic fine particles is at least 2 satisfying the following relational expression.
1. A method for producing a toner for developing an electrostatic charge image, which comprises one kind of inorganic fine particles (A, B). 10 <Qa-Qb <3000 0 <Qb <50 However, Qa: charge amount of inorganic fine particles (A) (μC / g) Qb: charge amount of inorganic fine particles (B) (μC / g)