JP2784923B2 - Electrostatic image developing toner and electrostatic image developer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention comprises a toner for developing an electrostatic image for developing a latent image in electrophotography, and the toner for developing an electrostatic image and carrier particles. A two-component electrostatic image developer.

<Prior Art> Electrostatic image development in an electrophotographic apparatus is generally performed as follows.

The surface of the photoconductor is positively or negatively charged.

The surface of the photoreceptor is irradiated with light reflected from the original.

The photoreceptor increases conductivity when irradiated with light.Therefore, a portion where the charge is lost and a portion where the charge remains are generated on the surface of the photoreceptor in accordance with the intensity of the reflected light from the document, and a latent image is formed on the surface of the photoreceptor. Is formed.

The developing toner charged to the opposite polarity to the charge on the surface of the photoreceptor is adhered to the surface of the photoreceptor from a toner carrier or the like by electrostatic attraction to form a visible image.

After transferring the visualized image to the transfer paper surface, the image is fixed by heating, pressing and the like.

In such electrostatic image development, a one-component or two-component toner is used as the developing toner.

The two-component developing toner is composed of toner particles made of resin powder containing a colorant and carrier particles made of iron or ferrite. The two-component developing toner is charged by friction between toner particles and carrier particles. The charge polarity is controlled by selecting a carrier particle constituting material, coating a resin on the surface of the carrier particles, and selecting a charge control agent to be contained in the developing toner.

On the other hand, the one-component developing toner does not use carrier particles, and is described in, for example, US Pat. Nos. 3,909,258 and 4,219,191.
As shown in the specification, the toner consists of magnetic toner particles containing a magnetic powder which is itself a colorant.

Such charging of the one-component developing toner is performed by friction between the magnetic toner particles and a blade / toner carrier or the like in contact with the magnetic toner particles, or friction between the magnetic toner particles. However, in such charging by friction, it is difficult to charge all the toner particles to the same polarity, and the charge amount is also insufficient.

When a magnetic toner holding only an insufficient amount of charge is used as a developing toner, image quality is easily deteriorated such that an image is disturbed. Therefore, as a method for stably obtaining a high-quality image, it is desirable to use a two-component developing toner having a sufficient charge amount.

<Problems to be Solved by the Invention> However, the two-component developing toner has the following problems.

Since the toner particles are charged by friction with the carrier particles, the surface of the carrier particles is easily contaminated by the components of the toner particles.

Since the individual toner particles have an irregular distribution, the charge control itself is incomplete.

The control of the toner (%) becomes insufficient due to the deterioration of the carrier particles, which has an adverse effect on the replenishment of the toner particles.

As described above, when mixed with the carrier particles, the rise of the charge is slow, the amount of charge of the toner particles changes with time, and the influence on the image quality such as the image density, fog and resolution becomes large. Further, the toner for development may be scattered in the machine.

The present invention has been made to solve the above-described problem in the two-component developing toner.
Small change in image density over time, little fogging and little deterioration over time, high resolution and small deterioration over time, rapid rise in charge, and small electrostatic charge image developing toner and electrostatic image developer The purpose is to provide.

<Means for Solving the Problems> The above object is achieved by the present invention described below.

 That is, the present invention includes the following (1) to (9).

(1) Chargeable insulative non-magnetic toner particles and chargeable insulative magnetic toner particles having the same polarity as the chargeable insulative nonmagnetic toner particles; An electrostatic image developing toner containing 0.01 to 10 parts by weight of toner particles.

(2) The toner for developing an electrostatic charge image according to (1), wherein the electrical conductivity of the chargeable insulating non-magnetic toner particles and the electrical conductivity of the chargeable insulating magnetic toner particles are 10 ⁻¹² mho / cm or less.

(3) The above (1) or (2), wherein the volume average particle diameter of the chargeable insulating nonmagnetic toner particles is 5 to 30 μm, and the volume average particle diameter of the chargeable insulating magnetic toner particles is 2 to 10 μm. The toner for developing an electrostatic charge image according to the above item.

(4) Saturation magnetization (σ) of the chargeable insulating magnetic toner particles
m) is 2 to 45 emu / g, the electrostatic image developing toner according to any one of the above (1) to (3).

(5) The electrostatic image development according to any one of (1) to (4) above, wherein the chargeable insulating nonmagnetic toner particles and the chargeable insulating magnetic toner particles contain a styrene-acrylic copolymer resin. For toner.

(6) The toner for developing an electrostatic image according to any one of the above (1) to (5), further comprising a fluidizing agent having the same polarity as the charged insulative non-magnetic toner particles.

(7) The electrostatic image developing toner according to (6), wherein the fluidizing agent is colloidal silica.

(8) An electrostatic image developer containing the toner for developing an electrostatic image according to any one of (1) to (7) and carrier particles.

(9) The electrostatic image developer according to the above (8), wherein the carrier particles are Mg-Cu-Zn ferrite.

JP-A-53-35546 discloses a developer for developing an electrostatic image, and this developer is made of a conductive magnetic powder (conductivity of 10 ^-4 to 10 ^-11 mho / cm). And an insulating non-magnetic powder (conductivity of 10 ⁻¹² mho / cm or less), and is a one-component developer using no carrier particles. Moreover, according to the description of the publication, the conductive magnetic powder and the insulating non-magnetic powder are opposite to each other in the same manner as the toner particles and the carrier particles are charged to opposite polarities in a two-component system. It is charged to a polarity. Therefore, the electrostatic image developer described in this publication has a completely different structure from the electrostatic image developing toner of the present invention.

Japanese Patent Application Laid-Open No. 60-159752 discloses that "a high-resistance carrier, an insulating toner charged to a certain polarity by contact with the carrier, and a polarity opposite to the frictional charging polarity of the toner by contact with the toner. Powder developer for electrostatic image development, characterized by being mixed with insulating particles having an average particle diameter of 8 μm or more that are triboelectrically charged but are not actually triboelectrically charged by contact with the carrier ” Is disclosed. According to the publication, the toner is capable of rapidly raising the charge due to the contact of the toner with the carrier, and the insulating particles are separated from the toner at the time of development and the electrostatic latent image carrier (photosensitive). Since it adheres to the non-image portion of the body, it does not adversely affect the copy paper.

However, in this case, since the insulating particles adhere to the photoconductor, a cleaning device for the photoconductor is required, and the photoconductor is deteriorated. Further, since the insulating particles do not form an image, the toner density is reduced as a result, and the transfer efficiency is reduced.

Hereinafter, a specific configuration in the case where the toner for developing an electrostatic image of the present invention is used in a two-component developer, that is, in the case where the toner is mixed with carrier particles and used, will be described in detail.

The toner for developing an electrostatic image according to the present invention comprises charged non-magnetic toner particles (hereinafter referred to as non-magnetic toner particles) and charged insulating magnetic toner particles having the same polarity as the non-magnetic toner particles (hereinafter referred to as magnetic toner particles). It contains.

By containing magnetic toner particles of the same polarity in addition to non-magnetic toner particles, the rise of charge at the time of toner replenishment is expedited, thereby suppressing the change over time of the charge amount and reducing image density, fog, resolution, etc. Keep it stable,
Further, it has an effect of preventing scattering of the developing toner in the apparatus.

In the present invention, the electric conductivity of the non-magnetic toner particles and the magnetic toner particles is preferably 10 ⁻¹² mho / cm or less, more preferably 10 ⁻¹⁴ mho / cm or less. When the conductivity exceeds the above range, the so-called image quality such as fog and resolution tends to be adversely affected.

The non-magnetic toner particles are made of a resin containing a colorant, and further contain a charge control agent, a wax, a resistance adjuster, and the like as needed.

The magnetic toner particles are made of a resin containing a magnetic powder, and further contain a charge control agent, a wax, a colorant, a resistance adjuster, and the like as needed.

The volume average particle diameter of the non-magnetic toner particles is preferably 5 to
30 μm, especially 5.0-20.0 μm, more preferably 9.0-12.0 μm
m.

When the volume average particle diameter is less than the above range, toner aggregation occurs, the toner tends to be highly charged, and the image density tends to decrease and cleaning failure tends to occur. If the ratio exceeds the above range, the charge becomes low, and the fog and the in-flight scatter are likely to be deteriorated.

The volume average particle diameter of the magnetic toner particles is preferably 2 to 10
μm, especially 2.0 to 9.5 μm, more preferably 7.0 to 9.0 μm
It is. When the volume average particle diameter is less than the above range, the toner is highly charged and the image density is easily reduced. When the volume average particle diameter is more than the above range, the toner clamp is easily generated on the black solid image portion.

The content ratio of these toner particles is determined by specific magnetic toner particles
For 100 parts by weight, magnetic toner particles are 0.01 to 10 parts by weight,
Particularly, it is 0.03 to 5.0 parts by weight, more preferably 0.1 to 0.7 parts by weight. If the content ratio of the magnetic toner particles is less than the above range, various problems of the existing two-component toner occur. If the content ratio exceeds the above range, selective development of the specific magnetic toner and the magnetic toner occurs.

The saturation magnetization (σm) of the magnetic toner particles is preferably 2
4545 emu / g, more preferably 3 to 30 emu / g. If σm is less than the above range, various problems of the present two-component toner are likely to occur, and if σm exceeds the above range, photoreceptor deterioration tends to be promoted.

In the present invention, the resin used for the specific magnetism and the magnetic toner particles may be selected from known resins according to a fixing method such as heating or pressure bonding, and is not particularly limited. The resins suitably used in the present invention are, for example, those described below.

That is, polyethylene, olefin resin such as polypropylene, polymethacrylic acid ester, methacrylic acid copolymer, acrylic resin such as acrylic acid copolymer, styrene copolymer such as styrene-acrylic copolymer, ethylene-vinyl acetate Various vinyl resins such as copolymers and polyvinyl chloride; polyamide resins such as polymerized fat-modified polyamide; alkyd resins such as phthalic acid resin and maleic acid resin; epoxy resins; synthetic resins such as phenol formaldehyde resin; And one or more of various resins such as polyester resin.

Among these resins, it is particularly preferable to use a styrene-acryl copolymer resin and a polyester resin, especially a styrene-acryl copolymer resin.

In this case, the styrene-acrylic copolymer is obtained by a copolymerization reaction of styrene and its derivative with a (meth) acrylic monomer which can be copolymerized.

As copolymerizable acrylic monomers, methyl acrylate, ethyl acrylate, isopropyl acrylate,
N-butyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, hydroxypropyl acrylate, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-methacrylate One or more of acrylates or methacrylates such as hexyl, lauryl methacrylate, 2-hydroxyethyl methacrylate, and hydroxypropyl methacrylate are exemplified.

The colorant may be selected according to the purpose, and is not particularly limited. Suitable coloring agents include, for example, pigments and dyes such as carbon black, copper phthalocyanine, Dupont oil red, quinoline yellow, methylene blue, chrome yellow, azo dyes, and nigrosine dyes.

The content of such a colorant is preferably about 3 to 20 parts by weight based on 100 parts by weight of the resin of the specific magnetic toner particles. When the colorant is contained in the magnetic toner particles, it is preferably about 1 to 10 parts by weight based on 100 parts by weight of the resin of the magnetic toner particles.

The charge control agent is added as needed to limit the charge polarity, charge amount, and the like. In the present invention, the intended polarity,
A known suitable charge control agent may be selected according to the charge amount and the like, and there is no particular limitation. For example, metal complex salt azo dyes,
Nigrosine dyes and the like can be mentioned, and these are selected according to required characteristics.

The content of such a charge control agent is preferably about 0.3 to 5 parts by weight per 100 parts by weight of the resin in the non-magnetic toner particles.

Also, the content of the magnetic toner particles is preferably about 0.3 to 5 parts by weight based on 100 parts by weight of the resin.

Wax is added as a release agent as needed to prevent offset. In the present invention, the wax used is not particularly limited, and various known waxes, for example, polyethylene wax, polypropylene wax, silicon wax, etc. may be used, and these are selected according to required characteristics. The content of such a wax is preferably about 2 to 7 parts by weight per 100 parts by weight of the resin in the non-magnetic toner particles. In the magnetic toner particles, the content is preferably about 1 to 7 parts by weight based on 100 parts by weight of the resin.

There is no particular limitation on the magnetic powder contained in the magnetic toner particles, and known magnetic powders such as magnetite and various ferrites may be used, and these are selected according to required characteristics.

Such a magnetic powder may be contained so that the σm of the magnetic toner particles is in the above range, and varies depending on the type of the magnetic powder. For example, 5 to 70 parts by weight based on 100 parts by weight of the resin of the magnetic toner particles It is preferable that the content be contained in the order of parts.

The non-magnetic toner particles and the magnetic toner particles include:
In addition to these, a resistance adjusting agent may be contained.

The non-magnetic toner particles and the magnetic toner particles may be manufactured by a usual toner manufacturing method, for example, manufactured as described below.

From the above-mentioned colorant, charge control agent, wax, magnetic powder, other additives, etc.
These predetermined amounts and the resin are melted and kneaded, cooled, and coarsely pulverized by a hammer mill, a cutter mill or the like. Then
After finely pulverized by a jet mill, an ong mill or the like, non-magnetic or magnetic toner particles are obtained by preferably classifying the particles into the above-mentioned volume average particle size range.

The non-magnetic toner particles and the magnetic toner particles thus obtained are mixed by a Henschel mixer, a grind mixer, or the like, and the magnetic toner particles are attached to the surface of the non-magnetic toner particles. Used as

The toner for developing an electrostatic image of the present invention preferably contains a fluidizing agent having the same polarity as these in addition to the non-magnetic toner particles and the magnetic toner particles. As the fluidizing agent, any known fluidizing agent may be used as long as it has the same polarity as the non-magnetic toner particles and the magnetic toner particles, but a particularly preferred fluidizing agent in the present invention is colloidal silica. Colloidal silica is fine particles of silica. In the present invention, colloidal silica having an average particle size of about 0.01 to 0.5 μm is preferably used.

The content of the fluidizing agent is preferably 0.1 to part by weight, more preferably 0.3 to 0.1 part by weight, based on 100 parts by weight of the non-magnetic toner particles.
8 parts by weight. When the content of the fluidizing agent is less than the above range, toner aggregation occurs, and the fluidity tends to deteriorate.
When the ratio exceeds the above range, deterioration of the photoreceptor and instability of the charge amount are caused, which easily affects the image quality.

When a fluidizing agent is contained in the electrostatic image developing toner of the present invention, nonmagnetic toner particles, magnetic toner particles and a fluidizing agent are mixed with a Henschel mixer or the like as described above,
The magnetic toner particles and the fluidizing agent are made to adhere to the surface of the non-magnetic toner particles and used as a toner for developing an electrostatic image.

The electrostatic image developing toner of the present invention is usually mixed with carrier particles and used as a two-component electrostatic image developer.

The carrier particles to be used are not particularly limited, and known carrier particles composed of Fe, various ferrites, and the like may be used. However, Mg-Cu-Zn-based ferrite is preferably used because charge control is easy.

In the present invention, the volume average particle size of the carrier particles is preferably 40 to 120 μm, more preferably 75 to 120 μm.

In the electrostatic image developer composed of such carrier particles and the above-described toner for developing an electrostatic image, the content of the toner for developing an electrostatic image is preferably 2 to 10% by weight, more preferably 3.5 to 10% by weight. 4.5 wt%.

Such an electrostatic image developer of the present invention exhibits a predetermined effect when used as a two-component developer in a dry developing method such as a magnetic brush developing method, a cascade method, a bristle brush method, and a powder cloud method.

The electrostatic image developing toner of the present invention can also be used as a one-component developer without being mixed with carrier particles. For example, JP-B-41-9475, JP-B-45-2877, JP-B-54-3624, U.S. Pat. It can also be suitably used for a method. Further, it can be suitably used for the FEED developing method described in JP-A-57-114163.

<Example> Hereinafter, the present invention will be described in more detail with reference to specific examples of the present invention.

[Example 1-1] Styrene / acrylic resin (styrene 70-methyl methacrylate 20-butyl acrylate 10) 85 parts by weight Polypropylene wax (Viscol 550P manufactured by Sanyo Chemical Industries, Ltd.) 3 parts by weight carbon black (MA manufactured by Mitsubishi Industrial Chemicals Corporation) -100) 10 parts by weight Charge control agent (TRH manufactured by Hodogaya Chemical Co., Ltd.) 2 parts by weight After dissolving and kneading the above substances, the mixture was cooled and coarsely pulverized with a hammer mill. Subsequently, it was finely pulverized by a jet mill and classified to prepare various non-magnetic toner particles.

Next, 83 parts by weight of styrene / acrylic resin (styrene 78-butyl acrylate 22) 15 parts by weight of magnetite (TFP-2 manufactured by TDK Corporation) 2 parts by weight of charge control agent (TRH manufactured by Hodogaya Chemical Co., Ltd.) After melting and kneading, the mixture was cooled and coarsely pulverized by a hammer mill. Subsequently, it was finely pulverized by a jet mill and classified to prepare various magnetic toner particles.

The non-magnetic toner particles and magnetic toner particles produced as described above and a fluidizing agent (colloidal silica: R-972 manufactured by Nippon Aerosil Co., Ltd.) were mixed using a Henschel mixer, and toner Nos. 1 to 1 shown in Table 1 were mixed. 5 was obtained. As a result of observing these toners with a transmission electron microscope and EPMA,
It was confirmed that the magnetic toner and the fluidizing agent were attached to the surface of the non-magnetic toner. Incidentally, non-magnetic toner particles,
The magnetic toner particles and the fluidizer were all of the same polarity.

Table 1 shows the contents of the non-magnetic toner particles, the magnetic toner particles and the fluidizing agent in each toner.

Further, the conductivity and volume average particle size of the non-magnetic toner particles and the conductivity, volume average particle size and σm
Are shown in Table 1.

Example 1-2 Toner Nos. 11 to 13 shown in Table 1 were produced in the same manner as in Example 1-1, except that the raw materials of the nonmagnetic toner particles and the magnetic toner particles were as follows.

(Non-magnetic toner particles) Polyester resin 82 parts by weight Polypropylene wax (Viscol 550P manufactured by Sanyo Chemical Industries) 3 parts by weight Carbon black (MA-100 manufactured by Mitsubishi Industrial Chemicals) 10 parts by weight Charge control agent (TRD manufactured by Hodogaya Chemical Co., Ltd.) 0.5 parts by weight (magnetic toner particles) 82 parts by weight of polyester resin Magnetite (TFP-2 manufactured by TDK Corporation) 15 parts by weight Overcharge control agent (TRH manufactured by Hodogaya Chemical Co., Ltd.) 0.5 parts by weight [Comparative Example 1-1] For comparison, Example 1 except that no magnetic toner was contained
In the same manner as in No.-1, toner Nos. 101 to 103 shown in Table 1 were produced. In addition, toner No. 1 containing two kinds of non-magnetic toner particles having different volume average particle diameters without containing magnetic toner particles
04 was also made. The non-magnetic toner particles and the magnetic toner particles used in these toners had the same composition as in Example 1-1.

[Comparative Example 1-2] For comparison, Example 1 was repeated except that no magnetic toner was contained.
In the same manner as in -2, Toner No. 111 shown in Table 1 was prepared.

Example 2-1 Various toners prepared in Example 1-1 and Mg-Cu-Zu
Ferrite carrier particles (TFC-040 manufactured by TDK Corporation) were mixed to obtain various developers each containing 4.0 wt% of toner. Toner N contained in each developer
o. is shown in Table 2.

Comparative Example 2-1 Using the various toners produced in Comparative Example 1-1, various developers containing 4.0 wt% of each toner were produced in the same manner as in Example 2.

The developers prepared in Example 2-1 and Comparative Example 2-1 were applied to an electrophotographic copying machine (BD-7720 manufactured by Toshiba Corporation), and the following items were evaluated. The copy manuscript used was a dataquest chart, an electrophotographic society chart, a running test pattern, and the like. Table 2 shows the results.

(Image Density) The copy image density at the initial stage and after copying 50,000 sheets was measured with a photovolta densitometer (manufactured by Tokyo Denshoku Co., Ltd.).

(Charge amount) The charge amount of the toner at the initial stage and after copying 50,000 sheets is measured by a blow-off charge amount measuring device (TB-20 manufactured by Toshiba Chemical Corporation).
0). The measured values shown in Table 2 are 10 second values.

(Fog) The white background and the white background of plain paper of the toner image (Chart of the Society of Electrophotography) at the initial stage and after copying 50,000 sheets were measured with a photovolt densitometer (manufactured by Tokyo Denshoku Co., Ltd.), and the following formula was used. I asked for fog.

(Resolution) The resolution of the copied images at the initial stage and after copying 50,000 sheets was measured by a line densitometer (manufactured by Tokyo Denshoku KK).

(In-machine scattering) After 50,000 sheets were copied, developer scattering in the copying machine was measured.
The details of the evaluation shown in Table 2 are as follows.

：: minute Δ: medium ×: large (toner clamp) The occurrence of toner clamp was visually confirmed in the black solid image at the initial stage and after copying 50,000 sheets.

○: No ×: Yes As is evident from Table 2, Developer Nos. 101 to 103 containing no magnetic toner particles showed insufficient results with respect to resolving power, fog and in-machine scattering. Developer No. 104 containing no magnetic toner particles but instead containing non-magnetic toner particles having the same volume average particle size as the magnetic toner particles
Also, the change of each characteristic with time was large.

In addition, the developer No. 4 showed a slightly large change in the amount of charge and a change in the image density, but showed very good results with respect to the resolving power, fogging and scattering inside the machine.

[Example 2-2] Various toners prepared in Example 1-2 and Mg-Cu-Zn
Ferrite carrier particles (TFC-040 manufactured by TDK Corporation) were mixed to obtain various developers each containing 4.0 wt% of toner. Toner N contained in each developer
Table 3 shows o.

Comparative Example 2-2 Various developers containing 4.0 wt% of each toner were produced in the same manner as in Example 2-1 using the various toners produced in Comparative Example 1-2.

The developer prepared in Example 2-2 and Comparative Example 2-2 was applied to an electrophotographic copying machine (BD-7720 manufactured by Toshiba Corporation), and the same items as described above were evaluated.

 Table 3 shows the results.

However, the image density, charge amount, fog, resolution, scattering inside the apparatus and toner clamp are values after copying 30,000 sheets.

Example 3 The above developer Nos. 2, 4, and 102 were agitated by a ball mill, and the rise of the charge amount was measured. The results are shown in FIG. The measurement of the charge amount was performed in the same manner as described above.

As is clear from FIG. 1, the developer No. 102 has a poor rise of the charge amount. On the other hand, the developer Nos. 2 and 4, which are the developers of the present invention, show a good start-up, and from Table 2 show that the charge amount and the image quality change over time, and the effect of preventing scattering in the machine is excellent. I understand.

<Effect of the Invention> The toner for developing an electrostatic image and the electrostatic image developer of the present invention have a small change over time in the amount of charge and a change over time in the image density because a rapid rise of charge can be obtained during toner replenishment. Further, fog and its deterioration with time are small. Further, it has an effect of stably maintaining a so-called high-quality image having a high resolving power and a small deterioration over time. Further, scattering of the developer in the machine is small.

[Brief description of the drawings]

FIG. 1 is a graph showing the rise of the charge amount of the electrostatic image developer of the present invention.

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshihiko Amano 1-13-1 Nihonbashi, Chuo-ku, Tokyo Inside TDK Corporation (56) References JP-A-57-85060 (JP, A) JP-A-59 -218458 (JP, A) JP-A-63-206765 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03G 9/08 G03G 9/083

Claims (9)

(57) [Claims] Claims: 1. A method according to claim 1, wherein the non-magnetic toner particles have the same polarity as the chargeable non-magnetic toner particles and 100 parts by weight of the non-magnetic toner particles.
A toner for developing an electrostatic image, comprising 0.01 to 10 parts by weight of the above-mentioned chargeable insulating magnetic toner particles. 2. The charge-insulating non-magnetic toner particles and the charge-insulating magnetic toner particles have an electrical conductivity of 10 ^-12 mho / c.
2. The toner for developing an electrostatic image according to claim 1, wherein the toner is not more than m. 3. The charge-insulating non-magnetic toner particles have a volume average particle size of 5 to 30 μm, and the charge-insulating magnetic toner particles have a volume average particle size of 2 to 10 μm. 3. The toner for developing an electrostatic image according to item 1. 4. The electrostatic charge image developing toner according to claim 1, wherein said charged insulative magnetic toner particles have a saturation magnetization (σm) of 2 to 45 emu / g. 5. The electrostatic charge image developing device according to claim 1, wherein said chargeable insulating non-magnetic toner particles and said chargeable insulating magnetic toner particles contain a styrene-acrylic copolymer resin. toner. 6. The toner for developing an electrostatic image according to claim 1, further comprising a fluidizing agent having the same polarity as the chargeable insulating nonmagnetic toner particles. 7. The toner according to claim 6, wherein the fluidizing agent is colloidal silica. 8. An electrostatic image developer comprising the electrostatic image developing toner according to claim 1 and carrier particles. 9. The electrostatic image developer according to claim 8, wherein the carrier particles are Mg-Cu-Zn ferrite.