JPH041766A - Electrostatic charge image developing toner - Google Patents

Abstract

PURPOSE:To improve the durability of the toner by using the resin grains of specified shape and forming a specified ruggedness on the grain. CONSTITUTION:When the radius of the inscribed circle in contact with the resin grain at at least three points in the plane of projection is denoted by (r) and the radius of the circumscribed circle by R, 1.00 < R/r <=1.20 has to be fulfilled. The ruggedness is formed on the grain, and the peripheral length L of the plane of projection and the circumference (l) of the inscribed circle are limited to conform to 1.01l < L < 2.00l. Since the appropriate ruggedness is formed on the surface of the toner in this way, the practically spherical shape is not deformed, and the deterioration of various additives with time is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a toner for developing electrostatic images, and more particularly to a toner for developing electrostatic images formed in electrophotography.

[Prior Art] Many methods are known for electrophotography, as described in US Pat. No. 2,297,691, etc.
Generally, a photoconductive substance is used to form an electrical latent image on a photoreceptor by various means, the latent image is developed using toner, and the toner image is transferred to a transfer member such as paper as necessary. After the image is transferred, it is fixed using heat, pressure, solvent vapor, etc. to obtain a copy.

Furthermore, various methods have been proposed as methods for developing with toner or methods for fixing toner images, and methods suitable for each image forming process are adopted.

In recent years, high-speed copying and high image quality have been required for electrophotography.

Generally, toner is produced by melt-mixing coloring agents such as dyes and pigments and additives such as charge control agents in a thermoplastic resin, uniformly dispersing the mixture, and then using a pulverizer and a classifier to form the desired particles. Methods are known for producing toners having a large diameter.

Toner produced by these pulverization methods generally has an amorphous shape, so there is a limit to faithfully reproducing a latent image, which is disadvantageous for achieving high image quality. In order to achieve high image quality in the pulverization method, it is necessary to pulverize particles into smaller particles. However, reducing the particle size has problems such as requiring more energy and poor toner yield.

As opposed to these irregularly shaped toners, spherical toners have been proposed. For example, in Japanese Patent Publication No. 56-13945, a spherical toner is obtained by a melt spray method, and in Japanese Patent Publication No. 57-51676, a small amount of an organic solvent is added to an amorphous toner, and the mixture is stirred under cooling. A method for obtaining spherical toner by this method is further disclosed in Japanese Patent Publication No. 36-10231, Japanese Patent Application Laid-open No. 59-53856, and Japanese Patent Application Laid-Open No. 59-538.
No. 9-61842 and the like disclose a method of obtaining a spherical toner using a polymerization method.

These spherical toners have a uniform shape and are easy to line up, so they tend to adhere faithfully to the latent image. Especially at the edges of the latent image, minute disturbances are eliminated, resulting in high image quality. Furthermore, when a spherical toner is obtained by a polymerization method, it is easy to reduce the particle size of the particles, making it suitable for achieving high image quality.

However, even when various additives are added to spherical toner, its properties tend to deteriorate (and it has been difficult to obtain toner with sufficient durability. Also, spherical toner does not adhere to the photoconductor). The adhesion was strong and toner cleaning after the transfer process was likely to be insufficient.

[Problems to be Solved by the Invention] An object of the present invention is to provide a toner that solves the above-mentioned problems.

An object of the present invention is to provide a toner that has high image density, excellent fine line reproducibility, and excellent highlight gradation.

An object of the present invention is to provide a toner whose performance does not change even after long-term use.

An object of the present invention is to provide a toner with almost no fogging or scattering.

[Means and effects for solving the problems] An object of the present invention is to provide resin particles containing at least a colorant and a binder resin;
In an electrostatic image developing toner containing at least one of a fluidity imparting agent, a lubricant, and an abrasive as an additive, the resin particles are in contact with the projection surface of the resin particles at at least three points. A spherical particle that satisfies the relationship 1.00<R/r≦1.20 between the inscribed circle with radius r and the circumscribed circle with radius R, and This is achieved by a toner for developing an electrostatic image, characterized in that unevenness satisfying the relationship of 1, olJ2 < L < 2.01 is formed on the resin particles between the circumference C of the tangent circle. .

The present invention will be explained in detail below.

As a result of intensive studies, the inventors of the present invention found that the deterioration in durability when various additives are used in combination with spherical toner is mainly caused by the shape of the toner. In other words, when the shape is spherical, the contact area is wide (for example, between toner and toner, between toner and carrier, between toner and sleeve, etc.), and it is easier to rub than an irregularly shaped toner, and as a result, it adheres to the toner surface. Freely movable additives are embedded and fixed on the toner surface, significantly inhibiting its function and resulting in poor durability.

Based on the above knowledge, we conducted further studies and arrived at the present invention. That is, it has been found that by creating appropriate irregularities on the surface of the toner, it is possible to prevent the deterioration of the durability of various additives without changing the actual shape.

Moreover, since the toner of the present invention is substantially spherical, high-quality images can be obtained as described above.

In the present invention, at least one of a fluidity imparting agent, a lubricant, and an abrasive is used as an additive.

When a fluidity imparting agent is used, the van der Waals force acting on the toner is weakened, and the toner exhibits a behavior more faithful to the Coulomb force. As a result, the toner can easily move from the toner carrier to the latent image on the photoreceptor, resulting in high image quality.
concentration can be obtained. Furthermore, since it is faithful to the latent image, it is possible to obtain an image without fog. moreover,
By using a fluidity imparting agent, toner replenishment becomes easier. In the case of a two-component developer, since the toner has good miscibility with magnetic particles, the toner is also well charged.

In general, the smaller the particle size of these fluidity imparting agents, the more
High ability to provide liquidity.

However, when a fluidity imparting agent is used in a spherical toner, because of its small particle size, it tends to be embedded inside the toner (and tends to lose its fluidity imparting effect).

In contrast, the present inventors have discovered that by combining a resin particle that is substantially spherical and has irregularities with a fluidity imparting agent, a toner whose fluidity imparting effect is less likely to deteriorate can be obtained. .

Further, in the present invention, a lubricant is used to assist in cleaning the toner on the photoreceptor. In order to obtain high-quality images, reducing toner particle size makes toner cleaning difficult.
This tends to appear as poor cleaning on images. In the present invention, since the toner has minute irregularities, it tends to be easier to clean. However, when used in combination with a lubricant, cleaning becomes easier even in the case of small particle size toner, and it can be applied to a simple cleaning device. became.

Further, in the present invention, an abrasive is used in order to prevent deterioration of image quality. The image quality deterioration referred to here refers to background smearing due to so-called filming. In other words, fixability,
As the durability of wax components contained in the resin and silica fine powder externally added to improve offset resistance progresses, a phenomenon occurs in which they adhere to the surface of the photoreceptor in a layered manner, and the areas corresponding to the adhesion occur. This is a phenomenon in which images become foggy or smudged.

To deal with this filming problem, Japanese Patent Laid-Open No. 50-10
As disclosed in Japanese Patent No. 631, a method has been proposed in which the surface of a photoreceptor is polished by adding an abrasive to toner to prevent filming.

Further, the addition of an abrasive has the effect of facilitating toner cleaning of the photoreceptor.

However, when an abrasive is used in a spherical toner at the same time as the above-mentioned fluidity imparting agent, the difference in hardness between the toner and the toner is too large and the particle size is relatively fine, so the abrasive tends to embed inside the toner (i.e., abrasive). It was easy to lose effectiveness.

On the other hand, the present inventors have discovered that by combining substantially spherical and uneven resin particles with an abrasive agent, a toner whose abrasive effect is less likely to deteriorate can be obtained.

In addition, since the toner is substantially spherical, it does not have sharp protrusions and is less likely to be pulverized during stirring in the developing device. As a result, there will be no fogging caused by an increase in powder, and there will be no scattering inside the machine.

The toner according to the present invention is substantially spherical and has minute irregularities on the surface, and the method for obtaining such a toner is as follows:
For example, the following methods may be mentioned.

1) Wet heat treatment method: After uniformly adhering child particles, which are particles smaller than the spherical particles, to spherical particles, they are dispersed in a liquid and subjected to heat treatment to fix the child particles to the surface of the spherical particles. .

2) Addition of child particles during toner particle polymerization - When obtaining toner particles by polymerization, child particles are added to the monomer in advance, or child particles are added during the polymerization process (child particles or dispersion system). (by controlling the physical properties of the toner), the polymerization is completed with the child particles protruding from the toner surface.

3) Mechanochemical method Two spherical particles and child particles are fused to the surface of toner particles using a mechanochemical method.

4) Dry heat treatment method: After mixing spherical particles and child particles, the mixture is heated in a fluidized heating bed to fix the child particles to the surface of the spherical particles.

5) Drying method after swelling: Toner particles are once immersed in a solvent and swelled, and then dried in a heated air stream or under reduced pressure.

This causes the surface to become wrinkled and uneven. At this time, spheroidization processing may also be performed.

6) Solvent Removal Method During Polymerization When toner particles are obtained by the duplex method, a soluble solvent is contained in the monomer in advance, and the solvent is removed during the polymerization reaction by raising the temperature or the like.

Due to the volumetric contraction at this time, the surface becomes wrinkled and uneven.

Examples of the spherical particles used in methods 1), 3), and 4) include particles obtained by the above-mentioned spheroidization treatment of irregularly shaped toner, polymerization method, and melt spray method. Further, from the viewpoint of high image quality, it is desired that toner particles be made smaller in diameter, and melt spraying and polymerization methods are suitable for meeting this demand. In particular, a polymerization method in which oil droplets are obtained under high shear force in water is a method suitable for reducing the particle size.

Similarly, the child particles used in methods l) to 4) above are:
Particles whose particle size is in the range of 1/200 to 1/10, preferably 1/100 to 1/10 of the spherical particles are good. In addition to thermoplastic resin, inorganic compounds such as magnetic particles can be used as the material for the child particles. However, since the child particles exist on the surface of the toner and affect the amount of charge on the toner, they must be appropriately charged. Preferably controlled.

As described above, the toner particles in the present invention are preferably substantially spherical, and between an inscribed circle of radius r and a circumscribed circle of radius R that touch the projection plane of the toner particles at at least three points. It is preferable that there is a relationship of 1.00<R/r≦1.20. When R/r becomes thick (the shape moves away from a spherical shape, and when it exceeds 1.20, the characteristics of a spherical toner no longer appear).

The volume average particle size of these spherical toners is 2 to 20 pm, preferably 3 to lgm, and more preferably 4 to 10 μm.

Furthermore, in the present invention, the relationship between the peripheral length of the projection plane and the circumference ρ of the inscribed circle is 1.01β<L<2.00! It is preferable that the following relationship is satisfied. Perimeter length is 1.01β
If it is smaller, there will be almost no unevenness, and 2.0
If it is larger than Of2, there will be many microscopic irregularities that are finer than the particle size of the additive, or there will be irregularities with a large head. Among these, the former cannot prevent the additive from deteriorating. In addition, in the latter case, the actual shape approaches an amorphous shape, making it difficult to obtain high image quality, and also making it easy to cause pulverization in the developing device.

In the present invention, the projection plane of toner particles means at least 2000 times or more, preferably 5000 times or more, using an electron microscope.
This refers to an image obtained by focusing on the contour of the particle at magnification, and using Luzex 5000, the radius r of the inscribed circle and circumscribed circle is determined as shown in FIG. 1(a).

R was determined, and the peripheral length was also determined as shown in FIG. 1(b).

R, r, and L are measured for at least 50 such toner images, preferably 100 or more, and it is preferable that the majority of toners fall within the claimed range.

As the fluidity imparting agent used in the present invention, any fluidity imparting agent can be used as long as it improves fluidity when added to the resin particles. Specific examples are given below, but the invention is not limited to these.

Metal fluorides such as silicon oxide, aluminum oxide, and titanium oxide, inorganic compounds such as carbon black and carbon fluoride, fluorine resin powders such as polyvinylidene fluoride and polytetrafluoroethylene, and fine powders such as fatty acid metal salts. One or more types may be used. The finer the particle size, the more suitable it is for the present invention; however, fine silica powder and fine alumina powder are easier to obtain (preferably. Fine silica powder subjected to surface hydrophobization treatment is more preferred).

As the lubricant used in the present invention, one or more resin powders are used. Specific examples are shown below, but the invention is not limited to these.

Fluororesin powders such as polytetrafluoroethylene and polyvinylidene fluoride, fatty acid metal salt powders such as zinc stearate and aluminum stearate, polyolefin powders, and fluorocarbon powders are used.

As the abrasive used in the present invention, one or more of inorganic metal hydride, nitride, carbide, sulfuric acid, or metal carbonate having a Mohs hardness of 3 or more is used. Specific examples are shown below, but the invention is not limited to these.

5rTiO's, CeO, Cry, ARzO, Mg
These include metal oxides such as O, nitrides such as 5idL, carbides such as SiC, and sulfuric acid or metal carbonate salts such as CaSO4゜BaSO4 and CaCO5.

Preferably 5rTiOs with a Mohs hardness of 5 or more, CRO
w (e.g. Mirek, Molek T, ROX M-1
Powder containing CeO□ and rare earth elements such as) + 5
zsL+ 5L-C is good.

These substances may also be surface-treated with a coupling agent such as a silane coupling agent, a titanium coupling agent, a zircoaluminate coupling agent, silicone oil, or other organic compound.

Among these additives, the fluidity imparting agent is
Based on the weight part, 0.1 to 5 parts by weight is used, preferably 0.1 to 3 parts by weight.

The lubricant and the abrasive are each used in an amount of 100 parts by weight of the toner particles.
0.1 to 10 parts by weight are used, preferably 0.1 to 5 parts by weight.
Parts by weight are used.

The resin particles of the present invention are composed of at least a colorant and a binder resin. combination, styrene and other vinyl monomers (e.g. acrylonitrile□
・Copolymers with butadiene, etc.), polyester resins,
Epoxy resins and the like are used alone or in combination.

Regarding the thermal properties of these binder resins, those having a glass transition point of 30 to 80°C, preferably 40 to 60°C are preferable from the viewpoint of blocking resistance and fixing properties.

As the colorant used in the present invention, known colorants can be used, such as carbon black, iron black, C,1
, Direct Red 1, c, r, Direct Red 4,
C,1, Acid Red 1, C,1, Basic Red 1. C, 1, Modern Tread 30. C, 1, Direct Blue 1. C, 1, Direct Blue 2, C, I.

Acid Blue 9, C, 1, Acid Blue 15, C,
I.

Basic Ivy Blue 3, C, 1, Basic Blue 5, C
, 1, Mordand Blue, C, 1, Direct Green 6, C, I, Hessick Green 4, C, ■, Dyes such as Hessick Green 6, yellow lead, cadmium yellow, Mineral Fast Yellow, Navel Yellow, Naphthol Yellow s1 Banza Yellow G, Permanent Yellow NCG, Tartrazine Lake, Molybdenum Orange, Permanent Orange GTR, Benzidine Orange G, Cadmium Red, Permanent Red 4R,
Watching Red Calcium Salt, Brilliant Carmine 3B.

Fast Violet B1 Methyl Violet Lake,
Pigments include navy blue, cobalt blue, alkali blue lake, Victoria blue lake, pheasant, rhodamine B1 phthalocyanine blue, first sky blue, pigment green B, malachite green lake, and final yellow green G.

Further, in order to use the toner as a magnetic toner, magnetic powder may be included. As such magnetic powder, a substance that is magnetized when placed in a magnetic field is used, and includes powder of ferromagnetic metals such as iron, cobalt, and nickel, and compounds such as magnetite and ferrite. In particular, when obtaining a toner using a polymerization method, it is necessary to pay attention to the polymerization inhibiting properties and aqueous phase migration properties of the colorant and magnetic material. It is better to perform hydrophobic treatment using a substance.

Further, in order to improve release properties during hot roll fixing, waxes, such as hydrocarbon compounds, which are generally used as release agents may be added to the toner. The waxes used in the present invention include paraffin/polyolefin waxes, modified products thereof, such as oxides and grafted products, as well as higher fatty acids, metal salts thereof, and amidox. These waxes have a softening point of 40 to 130 according to the ring and ball method (JIS K 2531).
℃, preferably 50 to 10℃,
If the softening point is 40° C. or lower, the blocking resistance and shape retention of the toner will be insufficient, and if the softening point is 130° C. or higher, the releasability effect will be insufficient.

In the present invention, it is desirable to add a charge control agent to the toner material for the purpose of controlling the chargeability of the toner. As these charge control agents, known ones are used,
For example, positive charge control agents include nigrosine dyes, triphenylmethane dyes, quaternary ammonium salts, amine and polyamine compounds, and negative charge control agents include salicylic acid metal compounds, monoazo dye metals, etc. compounds, styrene-acrylic acid copolymers, styrene-methacrylic acid copolymers, and the like.

Particle size distribution measurement in the present invention will be described.

The measuring device is a Coulter counter TA-II type (
CX-1 and an interface (manufactured by Nikkaki) that outputs a number average distribution 1 volume average distribution.
A personal computer (manufactured by Canon) is connected, and a 1% NaCj) aqueous solution is prepared using primary sodium chloride as the electrolyte.

As a measurement method, the electrolytic aqueous solution 100 to 150mj? 0.1 to 5 mjl of a surfactant, preferably an alkylbenzene sulfonate, as a dispersant! In addition, 0.5 to 50 mg of the measurement sample is added.

The electrolyte in which the sample was suspended was dispersed for about 1 to 3 minutes using an ultrasonic disperser, and the particle size distribution of particles of 2 to 40 μm was measured using a 100 gm aperture using the Coulter Counter TA-II. Measure and obtain the volume average distribution and number average distribution.

The volume average particle diameter is obtained from the volume average distribution 9 number average distribution thus determined.

In addition, regarding the particle size of the abrasive in the examples, Coulter
It is difficult to measure particle size with a counter. In the present invention, since the size of the toner surface is a problem, detailed measurements are performed using an electron microscope. That is,
Using an electron microscope, a photograph of the toner surface is observed at a magnification of at least 2000 times or more, preferably 5000 times or more. The particle size of at least 100, preferably 500 or more particles of the abrasive in the image is measured to determine the volume average diameter.

[Examples] Hereinafter, the present invention will be described in detail based on Examples. All parts are by weight.

111 mouths.

(Manufacture of spherical particles) Add 0.25 g of γ-aminopropyltrimethoxysilane to 100 mj of ion-exchanged water, further add 5 g of hydrophilic colloidal silica, heat to 70°C, and mix using a TK type homomixer M type (Tokushu Kikako Co., Ltd.). 10.00 Orpm using a pear-shaped
The mixture was dispersed for 15 minutes. Further l/l0N-)]Cj)
was added to adjust the system pH to 6.

The components of the above formulation were heated to 70° C. in a container, and dissolved and dispersed using an ultrasonic dispersion machine (1 OK Hz, 200 W) to obtain a monomer mixture. Furthermore, while maintaining the temperature at 70°C,
Initiator dimethyl 2,2'-azobisisobuticy 810
A monomer composition was prepared by adding and dissolving 1 part of the monomer.

The above monomer composition was put into a 2β flask containing the dispersion medium obtained above, and stirred at 8500 rpm for 60 minutes at 70 ° C. using a TK homomixer under a nitrogen atmosphere.
The monomer composition was granulated. Thereafter, polymerization was carried out at 70° C. for 20 hours while stirring with a paddle stirring blade.

After the polymerization reaction was completed, the reaction product was cooled, NaOH was added to dissolve the dispersant, and spherical particles were obtained by filtration, washing with water, and drying.

When the particle size of the obtained spherical particles was measured with a Coulter counter (aperture diameter 100H+), the particle size was found to have a volume average diameter of 9.0 βm and a sharp particle size distribution.

(Manufacture of resin fine particles) 150 parts of ion-exchanged water was placed in a reaction vessel and heated to 80°C, and further, while stirring, 1 part of a monomer system of styrene/n-butyl methacrylate = 90/10 (wt/wt) was added. 10 parts of an aqueous solution of lθ% ammonium persulfate were added thereto, 99 parts of the above monomer system were added dropwise over a period of 3 hours, and then 110 parts of methacryl was added dropwise, and the polymerization was continued for 1 hour. After the polymerization is completed, it is cooled, washed with water, filtered, and dried. Spherical resin fine particles having a volume average diameter of 0.5 μm were obtained by Coulter N4.

(Irregularization treatment) 5 parts of the resin fine particles were added to 50 parts of the spherical particles, and the mixture was dispersed and mixed using a Henschel mixer. Separately, add 4 parts of positively charged hydrophilic colloidal silica to 600 parts of ion-exchanged water.
It was distributed to different departments. The above mixed particle system was added to this dispersion medium system, and immobilization treatment was performed in an autoclave while heating and stirring (conditions: 110"C, 1.2kg/cm", 30 minutes). After the treatment, the dispersion medium system is cooled and further subjected to colloidal silica removal treatment, followed by water washing, filtration, and drying to form textured particles (R/r=1.10.L/j!=
1.30) was obtained.

To 100 parts of the obtained textured particles, 0.6 part of silica fine powder having a specific surface area of 200 m''/g by the BET method and hydrophobized with hexamethyldisilazane was externally added,
I used it as a toner. 92 parts of acrylic-coated ferrite carrier were mixed with 8 parts of this toner to prepare a developer.

Using the developer thus obtained, Canon C
As a result of a running test of 20,000 sheets with the LC-500, images with an image density of 1.4 or higher, no fog, very high resolution were stably obtained, and no toner cleaning defects occurred. , toner scattering inside the copier was not noticeable.

Arashi comparison (spherical particles) The same procedure as in Example 1 was carried out except that the homomixer condition during granulation was set to 7000 rpm.
．． Spherical particles with a sharp particle size distribution of 1 μm were obtained.

(Resin fine particles) The above formulation was stirred at 80° C. for 4 hours under a nitrogen stream to perform emulsion polymerization. Furthermore, 10 parts of methacrylic acid was added,
Polymerization was continued for 2 hours. After the polymerization is completed, it is cooled, washed with water, filtered, and dried until the volume average diameter is 0 by Coulter N4.
．． 05#Lm spherical resin fine particles were obtained.

(Immobilization treatment) The above spherical particles and fine resin particles were subjected to immobilization treatment in the same manner as in Example 1 to obtain particles. (R/r = 1.01゜L#
! = 1.005) To 100 parts of the obtained particles, 0.5 part of the same fine silica powder as that used in Example 1 was externally added to prepare a toner.

As a result of conducting a running test using this toner in the same manner as in Example 1, it was found that the image density decreased, especially during continuous copying, and defective toner cleaning occurred after 10,000 copies, and the degree gradually worsened. So I stopped running after 1000 tickets.

Add 0.25 g of γ-aminopropyltrimethoxysilane to 100 mA+ of ion-exchanged water, further add 5 g of hydrophilic colloidal silica, heat to 70°C, and mix using a TK homomixer M type (Tokushu Kako pear type). Dispersion was carried out for 15 minutes at 10.00 rpm. Furthermore, 1/10N-HCl was added to bring the pH in the system to 6.

Copolymer (mono uLt88:10:2. Mw =58
．． 000) 10 parts The ingredients of the above recipe were heated to 70°C in a container and dissolved and dispersed using an ultrasonic dispersion machine to form a monomer mixture, and then added and melted to form a monomer composition. Prepared.

The above monomer composition was charged into a 2I2 flask containing the dispersion medium obtained above, and stirred at 9000 rpm for 10 minutes under a nitrogen atmosphere at 70°C using a TK homomixer to dissolve the monomer. The composition was granulated. Thereafter, the polymerization reaction was carried out at 70°C for 8 hours while stirring with a paddle stirring blade, and then at 90°C.
Toluene was distilled off by raising the temperature to 0°C. After keeping at 90° C. for 1 hour to completely remove toluene, the reaction product was cooled, NaOH was added to dissolve the dispersant, and particles were obtained by filtration, washing with water, and drying.

When the particle size of the obtained particles was measured with a Coulter counter (aperture diameter 100 μm), the volume average diameter was 7.
It had a sharp particle size distribution of 5 μm. Furthermore, observation using an electron microscope confirmed that the surface of the particles had an irregular shape with depression-like undulations. (R/r
=1.15. L#! =1.35) This irregularly shaped particle 1
00 parts, the specific surface area by BET method is 100 m2
0.8 part of alumina fine powder of 0.2 g/g was added externally to prepare a toner. 92 parts of acrylic-coated ferrite carrier were mixed with 8 parts of this toner to prepare a developer.

Using the developer obtained in this way, a running test of 20,000 sheets was conducted using Canon's CLC-500, and the results showed that the image density was 1.4 or higher, and there was no fog (very Images with high resolution were stably obtained, and no toner cleaning defects occurred.

A polymerized toner was obtained in the same manner as in Example 1, except that the monomer mixture formulation in Example 1 was changed as follows.

Hydrophobic magnetic material is a hydrophilic magnetic material treated with a titanium coupling agent.

The particle size of the obtained particles was measured with a Coulter counter (aperture diameter 100 μm), and the volume average diameter was 10
．． It had a sharp particle size distribution at 6 pm. In addition, the magnetic particles adhere to the surface of the particles in a protruding manner to form unevenness (R/r = 1.08. L/R = 1.10
) was confirmed by electron microscopy.

To 100 parts of the irregularly shaped particles, 0.6 parts of fine silica powder having a specific surface area of 150 m''7 g by the BET method and hydrophobized with dimethyl silicone oil was added externally to prepare a toner.

Using the toner obtained in this way, we conducted a running test of 20,000 sheets using Canon NP-6650, and the results showed that the image density was 1.3 or higher, there was no fogging, and the images were stable with high resolution. No toner cleaning failure occurred.

Spherical particles were obtained in the same manner as in Example 1, except that paraffin wax was not added. The spherical particles were melt-kneaded using a roll mill, cooled, and then coarsely ground using a hammer mill to a particle size of approximately 1 to 2 nm+m. Then, it was pulverized using an air jet type pulverizer. Further, the obtained finely pulverized product was classified to obtain particles having a volume average diameter of 8.1 #Lm and a shape of particle size distribution almost the same as in Example 1.

The obtained particles were used as a developer in the same manner as in Example 1. Using this developer, 2
A running test of 0,000 sheets was conducted.

The image for evaluation was obtained by obtaining an unfixed image using CLC-500 and then performing good fixing using an external fixing device. As a result, there were no problems with image density, fogging, or toner scattering, but the resolution of the image was inferior to any of the examples.

In Example 1, the same procedure as in Example 1 was performed except that fine silica powder as a fluidity imparting agent was not used. From the beginning of running, the image density was less than 1.0, and there was no fogging. The image quality was so bad that I stopped running after 1000 images.

To 100 parts of the textured particles obtained in Example 1, 0.3 parts of polyvinylidene fluoride powder and 0.6 parts of hydrophobized silica fine powder were externally added, I used it as a toner.

92 parts of acrylic-coated ferrite carrier were mixed with 8 parts of this toner to prepare a developer.

Using the developer obtained in this way, we conducted a running test of 20,000 sheets on Canon's CLC-500, and as a result, images with extremely high resolution were stably obtained, and there were no toner cleaning defects. There was no noticeable scattering of toner inside the copier.

Storm Calibration A Toner was prepared by adding the same external additive as that used in Example 4 to 100 parts of the particles of Comparative Example 1 obtained by fixing spherical particles and resin particles. Using this toner, a running test was conducted in the same manner as in Example 1, and as a result, 1
At the time of 0,000 sheets, a toner cleaning failure occurred and the severity gradually worsened, so the running was stopped at 1,000 sheets.

To 100 parts of the amorphous particles obtained in Example 2, 0.3 part of polytetrafluoroethylene fine powder and 0.8 part of hydrophobic silica fine powder were added externally to prepare a toner. 92 parts of acrylic-coated ferrite carrier were mixed with 8 parts of this toner to prepare a developer.

Using the developer obtained in this way, we conducted a running test of 20,000 sheets using Canon's CLC-500, and as a result, images with extremely high resolution were stably obtained, and toner cleaning No defects occurred.

To 100 parts of the amorphous particles obtained in Example 3, 0.2 parts of fluorocarbon powder and 0 parts of hydrophobized silica fine powder were added.
．． A total of 6 parts were added externally to form a toner.

Using the toner obtained in this way, we conducted a running test of 20,000 sheets using Canon NP-6650, and as a result, images with high resolution were stably obtained, and no toner cleaning defects occurred. .

1.0 parts of strontium titanate having a volume average diameter of 0.30 parts m per 100 parts of the textured particles obtained in Example 1.
1 part and 0.5 part of hydrophobic silica fine powder are added externally,
I used it as a toner. 92 parts of acrylic-coated ferrite carrier were mixed with 8 parts of this toner to prepare a developer.

Using the thus obtained developer, a running test of 30,000 sheets was conducted using CLC-500 manufactured by Canon Inc. As a result, fog-free images with very high resolution were stably obtained.

The same external additive as that used in Example 7 was added to 100 parts of the particles of Comparative Example 1 obtained by fixing the spherical particles and the fine resin particles to prepare a toner. A running test was conducted using this toner in the same manner as in Example 7, and the results were as follows:
Toner cleaning failures began to occur after 10,000 sheets, and from around 20,000 sheets, background stains began to appear on the images. When the photoreceptor drum was examined after 30,000 sheets had been printed, it was confirmed that a low molecular weight resin was attached to the areas corresponding to background stains.

K5! 1 Paraffin wax (m,
Amorphous particles were obtained in the same manner as in Example 2, except that 40 parts of 32 parts (p, 155°F) were used.

For 100 parts of these irregularly shaped particles, the volume average diameter is 0.4
1.2 parts of cerium oxide of pm and 0.5 parts of hydrophobic silica were added externally to form a toner. A running test was conducted using this toner in the same manner as in Example 1, and as a result, fog-free images with very high resolution were stably obtained, and no toner cleaning defects occurred.

To 100 parts of the amorphous particles obtained in Example 3, 1.0 part of silicon nitride powder with a volume average diameter of 0.15 parts m and 0.6 parts of hydrophobized silica fine powder were added. It was added externally and used as a toner.

Using the toner obtained in this way, we conducted a running test of 20,000 sheets using Canon NP-6650, and the results showed that the image density was 1.3 or higher, there was no fogging, and the images were stable with high resolution. No toner cleaning failure occurred.

When the same procedure as in Example 8 was carried out except that cerium oxide, which is an abrasive, was not used, background stains became noticeable in the images after 20,000 sheets were printed.

At this time, when the photoreceptor drum was examined, it was found that low molecular weight resin had adhered to the drum.

[Effects of the Invention] According to the present invention, since moderate irregularities are formed on the surface of spherical toner particles, it is possible to prevent the durability of various additives from deteriorating, and there is no change in performance even after long-term use. , you can get images of excellent quality.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of toner particles of the present invention.

Claims (1)

[Scope of Claims] An electrostatic image developing toner comprising resin particles containing at least a colorant and a binder resin, and at least one of a fluidity imparting agent, a lubricant, and an abrasive as an additive, The resin particles have an inscribed circle with a radius r and a radius R that touch the projection plane of the resin particles at at least three points.
is a spherical particle that satisfies the relationship 1.00<R/r≦1.20 with the circumscribed circle of (2) the peripheral length L of the projection surface and the circumference l of the inscribed circle. A toner for developing an electrostatic image, characterized in that unevenness satisfying the relationship of 1.01l<L<2.00l is formed on the resin particles.