JPH11316474A - Magnetic toner, image forming method and process cartridge - Google Patents

Abstract

(57) [Problem] To provide a sharp image even when applied to a toner large-capacity developing device, to have a stable charging performance without fog even in long-term durability, and to cause no fading phenomenon. Provide a magnetic toner. SOLUTION: In a magnetic toner having magnetic toner particles containing at least a binder resin and magnetic iron oxide, the magnetic iron oxide contains Mn, Zn, N based on the iron element.
i, Cu, Co, Cr, Cd, Al, Sn and Mg, each containing at least one metal element selected from the group consisting of Mg and a silicon element in a specific amount; The ratio of the content B _si and content C _{si of} the silicon element present when the dissolution rate of the iron element is up to 20% by weight and up to 10% by weight, and the total silicon content A _si is within a specific range. The magnetic toner has a weight average particle diameter of 3.5 to 10.
0 μm and a particle size of 12.7 μ determined from the volume distribution.
A magnetic toner in which the content of magnetic toner particles of m or more is 0 to 30% by volume.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a magnetic toner used in an image forming method such as an electrophotographic method, an electrostatic printing method, a magnetic recording method, and a toner jet method, and an image forming method and a process using the magnetic toner. More particularly, the present invention relates to a toner for developing an electrostatic latent image for developing an electrostatic latent image, an image forming method using the toner, and a process cartridge.

[0002]

2. Description of the Related Art Conventionally, electrophotography has been disclosed in U.S. Pat. No. 2,297,691, Japanese Patent Publication No. 42-23910.
No. (corresponding US Pat. No. 3,666,363)
And Japanese Patent Publication No. 43-24748 (corresponding US Pat. No. 4,071,361),
Numerous methods are known. In general, a photoconductive substance is used to form an electric latent image on a photoreceptor by various means, and then the latent image is developed with toner to form a toner image to form a visible image. In accordance with the method, a toner image is transferred to a transfer material such as paper, and then fixed by fixing means such as heating, pressurizing, and heating and pressurizing to obtain a copy or print.

Various developing methods for visualizing an electrostatic latent image using toner have been known. For example, U.S. Pat.
The magnetic brush method described in U.S. Pat. No. 4,063, the cascade developing method described in U.S. Pat. No. 2,618,552 and the U.S. Pat. No. 2,221,776. Many developing methods such as powder cloud method, fur brush developing method and liquid developing method are known. Among these developing methods, in particular, a magnetic brush method, a cascade method, and a liquid developing method using a two-component developer mainly composed of a toner and a carrier have been put to practical use.
Each of these developing methods is an excellent method for obtaining a good image relatively stably, but has the problems associated with the two-component developer such as deterioration of the carrier and fluctuation of the mixing ratio of the carrier of the toner.

In order to solve such a problem, various developing methods using a one-component developer composed of only a toner have been proposed. Among them, many are excellent in a method using a one-component developer composed of magnetic toner particles.

US Pat. No. 3,909,258 proposes a developing method for developing using a magnetic toner having electrical conductivity. In this method, a conductive magnetic toner is supported on a cylindrical conductive sleeve having magnetism therein, and is contacted with an electrostatic latent image holding member having an electrostatic latent image for development. At this time, in the developing section, a conductive path is formed by the toner particles between the surface of the electrostatic latent image holding member and the surface of the sleeve, and electric charges are guided from the sleeve to the magnetic toner particles via the conductive path, thereby forming an electrostatic latent image. The toner particles adhere to the image portion and are developed by the cloning force between the image portion and the magnetic toner particles. The developing method using the conductive magnetic toner is an excellent method that avoids the problems associated with the conventional two-component developing method.However, since the toner is conductive, it is difficult to remove the toner from an electrostatic latent image holding member having a toner image. There is a problem that it is difficult to transfer electrostatically to a final supporting member such as paper.

As a developing method using a high-resistance magnetic toner capable of electrostatic transfer, there is a developing method utilizing dielectric polarization of toner particles. However, such a method has a problem that the developing speed is essentially low and it is difficult to obtain a sufficient density of a developed image.

Other developing methods using a high-resistance insulating magnetic toner include frictionally charging the magnetic toner particles by friction between the magnetic toner particles and friction between the magnetic toner particles and a friction member such as a sleeve to reduce the triboelectric charge. A development method for developing an electrostatic latent image with a magnetic toner is known. However, these methods are problematic in that the number of times of contact between the magnetic toner particles and the friction member is so small that triboelectric charging tends to be insufficient, and that the charged magnetic toner particles are liable to aggregate on the sleeve due to the strong cloning force between the sleeve and the sleeve. Have a point.

Japanese Patent Application Laid-Open No. 55-18656 (corresponding US Pat. Nos. 4,395,476 and 4,473,627) proposes a novel jumping developing method which eliminates the above-mentioned problems. I have. This involves applying a very thin layer of magnetic toner on a sleeve, triboelectrically charging it, and then developing the magnetic toner layer on the sleeve close to the electrostatic latent image. This method increases the chance of contact between the sleeve and the magnetic toner by applying the magnetic toner on the sleeve very thinly, enables sufficient frictional charging of the magnetic toner, supports the magnetic toner by magnetic force, and By moving the magnet and the magnetic toner as a whole, the cohesion between the magnetic toner particles is released and the toner is sufficiently rubbed with the sleeve, whereby an excellent image can be obtained.

In the insulating toner used in the above-mentioned developing method, a fine powdery magnetic substance is mixed and dispersed in a considerable amount, and a part of the magnetic substance is exposed on the surface of the toner particles. Affects the flowability and triboelectricity of the magnetic toner. As a result, various characteristics required for the magnetic toner, such as the development characteristics and durability of the magnetic toner, are affected.

More specifically, in a conventional jumping development method using a magnetic toner containing a magnetic substance, if a long-term repeated development process (for example, copying) is continued, a one-component system containing a magnetic toner is used. The fluidity of the developer is reduced, sufficient triboelectric charging is not obtained, the charging tends to be uneven, and the fogging phenomenon easily occurs in a low-temperature and low-humidity environment, which tends to cause a problem on an image. When the adhesiveness between the binder resin and the magnetic material constituting the magnetic toner particles is weak, the magnetic material is detached from the surface of the magnetic toner particles by the repeated development process, and adverse effects such as a decrease in the density of the toner image are caused. Tends to give.

When the dispersion of the magnetic material in the magnetic toner particles is not uniform, the magnetic toner particles containing a large amount of the magnetic material and having a small particle diameter accumulate on the sleeve, which is called image density reduction and sleeve ghost. In some cases, shading is observed.

Conventionally, magnetic iron oxides contained in magnetic toners are disclosed in JP-A-62-279352 (corresponding to US Pat. No. 4,820,603) and JP-A-62-2781.
No. 31 (corresponding US Pat. No. 4,975,214)
Has proposed a magnetic toner containing magnetic iron oxide particles containing a silicon element. In such magnetic iron oxide particles, a silicon element is positively present inside the magnetic iron oxide particles. However, in a magnetic toner containing the magnetic iron oxide particles, the fluidity of the magnetic toner should be further improved. Have a point.

Japanese Patent Publication No. 3-9045 (corresponding to European Patent Application Publication No. EP-A187434) proposes to control the shape of magnetic iron oxide particles to be spherical by adding a silicate. Since the magnetic iron oxide particles obtained by this method use silicate to control the particle size, a large amount of silicon element is distributed inside the magnetic iron oxide particles, and the amount of silicon element present on the surface of the magnetic iron oxide particles Less,
The fluidity of the magnetic toner tends to be insufficiently improved.

Japanese Patent Application Laid-Open No. 61-34070 proposes a method for producing ferric oxide by adding a hydroxosilicate solution during the oxidation reaction to ferric oxide. The triiron tetroxide particles obtained by this method have Si
Although the element is present, the Si element exists in a layer near the surface of the triiron tetroxide particles, and has a problem that the surface is weak against mechanical shock such as friction.

In Japanese Patent Application Laid-Open No. 5-72801 (corresponding to European Patent Application Publication No. EP-A5333069), a magnetic iron oxide particle contains 0.4 to 4% by weight of silicon element, and the magnetic iron oxide particles have In addition, a magnetic toner containing magnetic iron oxide particles in which 44 to 84% of the total silicon element content is present has been proposed.

However, in the magnetic toner containing the magnetic iron oxide particles, although the fluidity of the toner and the adhesion between the binder resin and the magnetic iron oxide particles are improved, the magnetic toner described in the production example is used. In the iron oxide particles, a large amount of a silicic acid component is present on the outermost surface, a pore structure is formed on the surface of the magnetic iron oxide particles, and the BET specific surface area of the magnetic iron oxide particles tends to be high. After being left in a high-humidity environment for a long period of time, the magnetic toner having a tendency to have reduced triboelectric charging characteristics.

JP-A-4-362954 (corresponding European Patent Application Publication No. EP-A468525) discloses magnetic iron oxide particles containing both silicon and aluminum elements, but further improvement in environmental characteristics is desired. It is rare.

Japanese Patent Application Laid-Open No. Hei 5-213620 discloses magnetic iron oxide particles containing a silicon component and having a silicon component exposed on the surface. However, as described above, further improvement in environmental characteristics is desired. It is rare.

Japanese Patent Application Laid-Open No. 7-239571 describes that a magnetic iron oxide particle contains a silicon component and further adjusts the Fe / Si ratio on the outermost surface. This improves the triboelectric charging property in a high-humidity environment.However, the magnetic iron oxide particles described in the production examples tend to have a high bulk density, and even when converted to toner, they are more likely to be used in a developing device. It becomes easier to tighten.

In a large-capacity system in which the amount of toner charged into the developing unit is increased in response to the recent increase in speed and life, such a magnetic toner is subjected to pressure by the toner's own weight and a stirrer, so that the magnetic toner is As a result, the toner tends to pack, which causes a shortage of the toner to be supplied to the sleeve, and the fading phenomenon that the image is stripped easily occurs.

Further, such a magnetic toner is insufficient in terms of improvement in fluidity, and when the cartridge is transported for a long time, the toner in the cartridge is tapped to one side to one side, and remains in that state. When image formation is started, the distribution of the magnetic toner on the sleeve is likely to be non-uniform, and image omission may occur.

JP-A-9-59024 and JP-A-9-59024
Japanese Unexamined Patent Publication No. 59025 discloses that Si is converted to 1.7 with respect to Fe.
And at least one metal element selected from Mn, Zn, Ni, Cu, Al and Ti as a metal element other than iron containing 0 to 4.5 atomic% of silicon in an amount of 0 to 10 atoms with respect to Fe. % Of magnetite particles.

Although the magnetic properties can be improved and the chargeability can be improved by this, the flowability of the toner cannot be sufficiently improved merely by adding the above metal. Have.

In order to further improve the fluidity of the toner, it is desired that the fluidity be improved not only by the magnetic material but also by other raw materials for toner.

JP-A-62-226260, JP-A-63-139365, JP-A-3-50559 and JP-A-6-208244 contain a polypropylene modified with a carboxylic acid or a maleic acid. Although toners or resin compositions for toners have been proposed, they have not been able to sufficiently improve the flowability of toners.

In recent years, there has been a demand for an image forming apparatus using electrophotography such as a copying machine and a laser beam printer to have a higher speed and a longer life, and to obtain a higher definition and higher image quality of the obtained toner image. Is required. The storage environment of the toner and the process cartridge filled with the toner is various, and the storage stability is important as the toner characteristics.

As for printer devices, LED and LBP printers have become the mainstream in the recent market, and the direction of technology has been increasing to higher resolution, that is, from 240,300 dpi to 400,600,1200 dpi. . Accordingly, the development system is required to have higher definition.

The functions of the copier have also been enhanced,
Therefore, it is moving toward digitalization. In this direction, the method of forming an electrostatic charge image with a laser is the main method, so it is also proceeding in the direction of high resolution, and here, as in the case of printers, high resolution and high definition development methods are required. JP-A-1-112253 and JP-A-2-112.
Japanese Patent No. 284158 proposes a toner having a small particle size.

However, by reducing the particle size of the toner, it is possible to form a high-resolution and high-definition image. On the other hand, the surface area per unit weight of the magnetic toner is increased. Since the amount increases, the fluidity of the magnetic toner decreases, and therefore,
The occurrence of the above-described fading phenomenon and the non-uniformity of the distribution of the magnetic toner on the sleeve become more remarkable.

[0030]

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic toner which solves the above-mentioned problems, an image forming method using the magnetic toner, and a process cartridge.

An object of the present invention is to provide a magnetic toner having a high image density and excellent image reproducibility, an image forming method using the magnetic toner, and a process cartridge.

An object of the present invention is to provide a magnetic toner which has no fogging even when used for a long time and has stable charging performance.
An object of the present invention is to provide an image forming method and a process cartridge using the magnetic toner.

It is an object of the present invention to provide a magnetic toner which has excellent charging characteristics even under a high humidity environment and further has excellent long-term storage stability, an image forming method using the magnetic toner, and a process cartridge. .

An object of the present invention is to provide a magnetic toner which does not cause a fading phenomenon even when applied to an image forming method having a large capacity developing device, an image forming method having the magnetic toner, and a process cartridge. It is in.

An object of the present invention is to provide a magnetic toner capable of forming a high-resolution and high-definition image and having no fading phenomenon even when applied to an image forming method having a large-capacity developing device. And an image forming method and a process cartridge having the magnetic toner.

An object of the present invention is to provide a magnetic toner that is stably supplied onto a sleeve even when toner in a cartridge is tapped on one side and does not cause image omission, an image forming method using the magnetic toner, and an image forming method. It is to provide a process cartridge.

[0037]

The above object is achieved by the following constitution of the present invention.

According to the present invention, there is provided a magnetic toner having magnetic toner particles containing at least a binder resin and magnetic iron oxide, wherein the magnetic iron oxide contains Mn, Z
n, Ni, Cu, Co, Cr, Cd, Al, Sn and M
g, containing at least one metal element selected from the group consisting of 0.2 to 0.4% by weight, and further containing 0.2 to 0.8% by weight of a silicon element. the ratio between the content a _si of the total silicon element iron element dissolution percentage of the magnetic iron oxide is present in the content B _si and in magnetic iron oxide of silicon element present up to 20 wt% (B _si / A _si ) ×
100 is a 45 to 85%, and the ratio between the content C _si and the content A _si of silicon element to an iron element dissolution percentage of the magnetic iron oxide is present in up to 10 wt% (C _si / A _si) × 100
Is 35 to 70%, the magnetic toner has a weight average particle diameter of 3.5 to 10.0 μm, and the content of magnetic toner particles having a particle diameter of 12.7 μm or more determined from the volume distribution is 0 to 70%. The present invention relates to a magnetic toner characterized by being 30% by volume.

Further, the present invention provides a latent image forming step of forming an electrostatic latent image on an electrostatic latent image holding member, and transferring the electrostatic latent image held on the electrostatic latent image holding member onto a toner holding member. A developing step of developing with a supported magnetic toner to form a toner image, wherein the magnetic toner has magnetic toner particles containing at least a binder resin and magnetic iron oxide. The magnetic iron oxide is composed of Mn, Zn, Ni, Cu, Co, Cr,
It contains 0.2 to 0.4% by weight of at least one metal element selected from the group consisting of Cd, Al, Sn and Mg, and further contains 0.2 to 0.8% by weight of a silicon element. The magnetic iron oxide has a silicon element content B _si existing when the iron element dissolution rate of the magnetic iron oxide is up to 20% by weight.
And the content A _si of the total silicon element present in the magnetic iron oxide
The ratio of _{(B si / A si) ×} 100 is 45 to 85%, and the content of silicon element of the iron element dissolution percentage of the magnetic iron oxide is present in up to 10 wt% C _si and the content A ratio of _{si (C si / a si)} × 100 is 35 to 70%, magnetic toner has a weight average particle diameter of 3.5 to 10.0μm
Wherein the content of magnetic toner particles having a particle diameter of 12.7 μm or more determined from a volume distribution is 0 to 30% by volume.

Further, according to the present invention, there is provided a process cartridge detachably mounted on an image forming apparatus main body, wherein the process cartridge includes an electrostatic latent image holding member for holding an electrostatic latent image, and the electrostatic latent image holding member. At least a magnetic toner for development, the magnetic toner includes magnetic toner particles containing at least a binder resin and a magnetic iron oxide, and the magnetic iron oxide is based on an iron element. As
Mn, Zn, Ni, Cu, Co, Cr, Cd, Al, S
a magnetic element containing 0.2 to 4.0% by weight of at least one metal element selected from the group consisting of n and Mg, and 0.2 to 0.8% by weight of a silicon element; Iron oxide has an iron element dissolution rate of 20% by weight of the magnetic iron oxide.
The ratio between the content A _si of the total silicon element present in the content B _si and in magnetic iron oxide of silicon element present up to (B _si /
A _si ) × 100 is 45 to 85%, and the ratio (C _si) of the content C _si of the silicon element and the content A _si of the magnetic iron oxide in which the iron element dissolution rate of the magnetic iron oxide is up to 10% by weight. / A _si )
× 100 is 35 to 70%, the magnetic toner has a weight average particle diameter of 3.5 to 10.0 μm, and a content of magnetic toner particles having a particle diameter of 12.7 μm or more determined from a volume distribution. The present invention relates to a process cartridge characterized in that the content is 0 to 30% by volume.

[0041]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have conducted intensive studies to solve the conventional problems, and as a result, by controlling the composition and structure of the magnetic iron oxide particles contained in the magnetic toner, a small particle size has been obtained. It has been found that the toner has extremely excellent fluidity, long-term storage stability, durability, and magnetic substance dispersibility in toner particles.

That is, in the present invention, the magnetic iron oxide used in the magnetic toner contains 0.2 to 0.8% by weight of silicon element based on iron element, and further contains Mn as a metal element other than iron. , Zn, Ni, Cu, Co, C
It is characterized in that it contains 0.2 to 4.0% by weight of at least one metal element (other metal element) selected from the group consisting of r, Cd, Al, Sn and Mg, based on the iron element. One of By using these other metal elements together with the silicon element to suppress the precipitation of silicon compounds in the vicinity of the surface of the magnetic iron oxide to some extent, and to supplement it with the other metal, impair the fluidity improvement effect of the magnetic iron oxide. Without moisture absorption.

In the present invention, the magnetic iron oxide contains 0.2 to 0.8% by weight, preferably 0.3 to 0.7% by weight of silicon element based on the iron element.

When the content of the silicon element is less than 0.2% by weight, the effect of improving the magnetic toner, particularly the improvement of the fluidity of the magnetic toner, is weak. If the content of the silicon element is more than 0.8% by weight, the charging characteristics are deteriorated in environmental characteristics, especially in long-term storage and long-term durability in a high-humidity environment. The dispersibility of the magnetic iron oxide in the binder resin also decreases.

When the content of the other metal element is less than 0.2% by weight, the effect of improving the fluidity of the magnetic toner is small. When the content of the other metal element is more than 4.0% by weight,
Magnetic iron oxide particles tend to adversely affect the charging characteristics of the magnetic toner.

In the present invention, the ratio between the content A _si of the total silicon element present in the magnetic iron oxide and the content B _si of the silicon element present when the iron element dissolution rate of the magnetic iron oxide is up to 20%. _{(B si / a si) ×} 100 is 45 to 85%, preferably from 50 to 80%, the content of the content C _si and total silicon element of the silicon element iron element dissolution ratio is present in up to 10% the ratio of the _{a si (C si / a si} ) × 100 is 35 to 7
0%, preferably 40 to 65%.

When (B _si / A _si ) × 100 is smaller than 45%, or when (C _si / A _si ) × 100 is smaller than 35%, a large amount of silicon is present inside the magnetic material, and In addition to easily deteriorating the process, there is a case where the magnetic iron oxide becomes unstable in magnetic properties. (B _si / A _si ) × 100 is 8
If it is greater than 5% or (C _si / A _si ) × 100 is 7
If it is more than 0%, a large amount of silicon element is present in the surface layer of the magnetic iron oxide, making it brittle against mechanical impact, and when used in a magnetic toner, harmful effects are likely to occur.

In the present invention, Mn, Zn, Ni, C in which the iron dissolution rate of the magnetic iron oxide exists up to 20% by weight.
content of one or more metal elements selected from the group consisting of u, Co, Cr, Cd, Al, Sn and Mg
_Metal and the ratio of the content A _Metal of the metal group element present in the magnetic iron oxide _{(B Metal / A Metal) ×} 10
0 is preferably 40 to 100%. (B _Metal /
If (A _Metal ) × 100 is less than 40%, it is difficult for other metals to effectively act near the surface, which is liable to be deteriorated even in the manufacturing process, and in addition, magnetic iron oxide may be unstable in magnetic properties.

In the present invention, when the magnetic iron oxide contains Mn element as another metal element, the M
The content of the n element is preferably based on the iron element,
The content is preferably 0.7 to 2.0% by weight, more preferably 0.8 to 1.8% by weight.

When the content of the Mn element is less than 0.7% by weight, the effect of improving the magnetic toner, particularly the improvement of the fluidity of the magnetic toner, is weak. When the content of the Mn element is more than 2.0% by weight, the charging characteristics may be deteriorated in environmental characteristics, particularly in long-term storage and long-term durability under high humidity, and further, the toner durability and toner Dispersibility of the magnetic iron oxide in the binder resin tends to decrease.

In the present invention, the ratio of the content A _Mn of the total Mn element present in the magnetic iron oxide to the content B _Mn of the Mn element present when the iron dissolution rate of the magnetic iron oxide is up to 20%. B _Mn / A _Mn × 100 is preferably 50 to 90%, more preferably 60 to 85%.

B _Mn / A _Mn × 100 is smaller than 50%,
If the Mn element is present in a large amount in the magnetic material, the manufacturing process is likely to be deteriorated and the magnetic properties may be unstable, resulting in a magnetic iron oxide. 90% of B _Mn / A _Mn × 100
In the case where the ratio exceeds 1, the Mn element is present in a large amount in the surface layer portion of the magnetic iron oxide, so that it becomes brittle against mechanical shock, and tends to have a bad influence on the charging characteristics.

In the present invention, when the magnetic iron oxide contains a Zn element as another metal element, the content of the Zn element in the magnetic iron oxide is preferably based on the iron element.
The content is preferably 0.2 to 0.8% by weight, more preferably 0.3 to 0.7% by weight.

When the content of the Zn element is less than 0.2% by weight, the effect of improving the fluidity of the magnetic toner is weak. Z
When the content of the n element is more than 0.8% by weight, the charging characteristics may deteriorate in the environmental characteristics and long-term durability, and further, the durability of the toner and the magnetic iron oxide in the toner binder resin may be reduced. Tends to decrease in dispersibility.

[0055] In the present invention, the ratio of the content A _Zn of total Zn element present in the magnetic iron oxide, the content B _Zn of Zn element entire element dissolution ratio of the magnetic iron oxide is present in up to 20% B _Zn / A _Zn × 100 is preferably 50 to 90%, more preferably 55 to 90%.

B _Zn / A _Zn × 100 is smaller than 50%,
When a large amount of Zn element is present inside the magnetic body, the manufacturing process is likely to be similarly deteriorated, and magnetic iron oxide may be unstable in magnetic properties. When _BZn / _AZn * 100 exceeds 90%, a large amount of Zn element is present in the surface layer of the magnetic iron oxide and becomes brittle against mechanical shock. When used in a magnetic toner, adverse effects are likely to occur. .

In the present invention, when the magnetic iron oxide contains a Cu element as another metal element, the content of the Cu element in the magnetic iron oxide is preferably based on the iron element.
0.01 to 0.8% by weight, more preferably 0.05
It is preferably from 0.7 to 0.7% by weight.

When the content of the Cu element is less than 0.01% by weight, the effect of improving the magnetic toner, in particular, the improvement of the fluidity of the magnetic toner is weak. When the content of the Cu element is more than 0.8% by weight, the charging characteristics may be deteriorated in environmental characteristics, particularly in long-term storage and long-term durability under high humidity, and furthermore, the toner durability and toner Dispersibility of the magnetic iron oxide in the binder resin tends to decrease.

In the present invention, the ratio of the total Cu element content A _Cu present in the magnetic iron oxide to the Cu element content B _Cu present when the iron element dissolution rate of the magnetic iron oxide is up to 10%. B _Cu / A _Cu × 100 is preferably 70 to 100%,
More preferably, it is 80 to 100%.

B _Cu / A _Cu × 100 is smaller than 70%,
When a large amount of Cu element is present inside the magnetic body, the manufacturing process is liable to be deteriorated, and magnetic iron oxide may be unstable in magnetic properties.

In the present invention, when the magnetic iron oxide contains a Ni element as another metal element, the content of the Ni element in the magnetic iron oxide is preferably based on the iron element.
The content is preferably 0.1 to 0.6% by weight, more preferably 0.2 to 0.6% by weight.

When the content of the Ni element is less than 0.1% by weight, the effect of improving the magnetic toner, particularly the improvement of the fluidity of the magnetic toner, is weak. When the content of the Ni element is more than 0.6% by weight, the charging characteristics may be deteriorated in environmental characteristics, particularly in long-term storage and long-term durability under high humidity, and further, the toner durability and toner The dispersibility of the magnetic iron oxide in the binder resin is also deteriorated.

In the present invention, the ratio of the total Ni element content A _Ni present in the magnetic iron oxide to the Ni element content B _Ni present when the iron element dissolution rate of the magnetic iron oxide is up to 20%. B _Ni / A _Ni × 100 is preferably 40 to 100%, more preferably 50 to 100%.

B _Ni / A _Ni × 100 is less than 40%,
When a large amount of Ni element is present inside the magnetic material, the manufacturing process is liable to be deteriorated, and magnetic iron oxide may be unstable in magnetic properties.

In the present invention, the magnetic iron oxide has a sphericity of preferably preferably 0.8 or more, more preferably 0.80 to 1.00, further preferably 0.82 to 1 based on a measuring method described later. .00.

When the sphericity is smaller than 0.80, the magnetic iron oxide particles come into surface-to-surface contact, and the particle size is 0.1
In the case of small magnetic iron oxide particles having a size of about 1.0 μm to about 1.0 μm, the particles cannot be easily separated from each other even with a mechanical shearing force, so that the magnetic iron oxide cannot be sufficiently dispersed in the magnetic toner. There is.

In the present invention, the magnetic iron oxide particles preferably have a bulk density of 0.4 to 0.8 g / m ³ , more preferably 0.5 to 0.7 g, based on a measuring method described later.
/ M ³ should be satisfied.

When the bulk density is less than 0.4 g / m ³ , it adversely affects the physical mixing property of the toner with other constituent materials during the production of the toner, and deteriorates the dispersibility of the magnetic iron oxide in the toner. Further, when the bulk density exceeds 0.8 g / m ³ , when the magnetic toner is used, the toner tends to be tight in a developing device, and the fluidity of the toner may be reduced to cause fading.

In the present invention, the magnetic iron oxide preferably has a number average particle diameter based on a measuring method described below, preferably of 0.0
The thickness is preferably from 5 to 1.00 μm, more preferably from 0.10 to 0.40, in view of the dispersibility of the magnetic toner in the binder resin and the uniformity of charging.

The number average particle size of the magnetic iron oxide is 1.00 μm
If the diameter is larger than the above, the number of magnetic iron oxide particles contained in the toner is reduced, so that the dispersion of the magnetic iron oxide in the binder resin is likely to be biased and the uniformity of charging is impaired. When the number average particle diameter of the magnetic iron oxide is smaller than 0.05 μm, the adhesive force between the magnetic iron oxide particles is increased, and the dispersibility in the binder resin is deteriorated.

In the present invention, the magnetic toner has a weight average particle diameter of 3.5 to 10.0 μm, preferably 4.5 to 9.0 μm, and a particle diameter of 1 to 10 μm determined from the volume distribution.
The content of the magnetic toner particles having a size of 2.7 μm or more is 0 to 30.
It is preferable to increase the resolution of the image by volume%, preferably 0 to 20% by volume, from the viewpoint of higher definition.

The weight average particle diameter of the magnetic toner is 10.0 μm.
If it is larger, the reproducibility of fine lines in graphic images and the sharpness of character contours will be poor. If the weight average particle size of the magnetic toner is smaller than 3.5 μm, the image density will be significantly reduced.

When the content of the toner particles having a particle diameter of 12.7 μm is more than 30% by volume, the magnetic toner has a remarkable difference in particle diameter from the contained fine powder toner, so that a uniform charging property is obtained. And fog tends to occur.

In the present invention, the volume average particle diameter of the magnetic toner is particularly preferably 2.5 to 6.0 μm from the viewpoint of high resolution and high definition.

When the volume average particle diameter of the magnetic toner is larger than 6.0 μm, the reproducibility of fine lines in a graphic image may be poor. 2.5μ volume average particle size of magnetic toner
If it is smaller than m, the image density tends to decrease.

In the present invention, the content of the magnetic toner particles having a particle diameter of less than 4.0 μm (particle diameter of 2.0 μm or more and less than 4.0 μm) determined from the number distribution is 10 to 40% by number. Is preferred in terms of image uniformity. When the content of the toner particles having a particle size of less than 4.0 μm is more than 40% by number, fogging due to non-uniform charging is likely to occur, and the content of the toner particles having a particle size of less than 4.0 μm Is less than 10% by number, the faithful image reproducibility is poor.

In the present invention, the magnetic toner is preferably prepared by adding magnetic iron oxide particles to 100 parts by weight of the binder resin.
20 to 200 parts by weight, more preferably 30 to 150 parts by weight.

When the content of the magnetic iron oxide is less than 20 parts by weight, the transportability is insufficient, and the developer layer on the developer carrier becomes uneven, which tends to cause image unevenness. When the content of the magnetic iron oxide exceeds 200 parts by weight, the image density decreases.

In the present invention, the magnetic iron oxide particles may be treated with a surface treating agent such as a silane coupling agent, a titanium coupling agent, titanate, aminosilane or an organosilicon compound.

In the present invention, as the binder resin for the magnetic toner, a homopolymer of styrene and its substituted substances such as polystyrene and polyvinyl toluene; styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinyl Naphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-
Octyl acrylate copolymer, styrene-dimethylaminoethyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene- Dimethylaminoethyl methacrylate copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer Styrene-based copolymers such as styrene-maleic acid copolymer, styrene-maleic acid ester copolymer; polymethyl methacrylate; polybutyl methacrylate; polyvinyl acetate; polyethylene; polyvinyl propylene; polyvinyl butyral; Resin; polyamide resin, epoxy resins, polyacrylic acid resins; rosin; modified rosins;
Temper resins; phenolic resins; aliphatic or cycloaliphatic hydrocarbon resins; aromatic petroleum resins; paraffin wax; and carnauba wax. These can be used alone or in combination. In particular, a styrene-based copolymer and a polyester resin are preferable in view of development characteristics and fixability.

In the present invention, the magnetic toner may contain a hydrocarbon wax and an ethylene olefin polymer (homopolymer or copolymer) together with a binder resin as fixing aids. The fixing property at the time of fixing is preferred from the viewpoint of high compatibility with the anti-offset property.

Here, those applied as an ethylene-based olefin homopolymer or an ethylene-based olefin copolymer include polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, and ethylene-ethyl acrylate copolymer. The copolymer includes an ionomer having a polyethylene skeleton, and the copolymer preferably contains 50 mol% or more (more preferably, 60 mol% or more) of an olefin monomer.

In the present invention, in particular, 1 to 30 mg KO
It is preferable to use a polypropylene wax having an acid value of H / g.

As a result of intensive studies by the present inventors, in the above-mentioned magnetic toner containing a specific magnetic iron oxide, a small particle size was obtained by controlling the acid value and thermal characteristics of the wax contained in the magnetic toner. It has been found that the toner has extremely excellent development sleeve coat stability, developability, durability, magnetic substance dispersibility in toner, fixability, and offset resistance.

That is, as described above, the magnetic iron oxide used in the present invention uses another metal element together with the silicon element to suppress the precipitation of silicon compounds near the surface of the magnetic iron oxide to some extent, By supplementing with metal, without impairing the fluidity improvement effect of magnetic iron oxide,
Hygroscopicity can be suppressed. Furthermore, by using a polypropylene wax having a specific acid value, the dispersibility of the wax in the binder resin is improved, the wax acts as a plasticizer for the binder resin, and the wax reduces the melt viscosity of the toner. By lowering it, the dispersibility of the magnetic iron oxide in the toner can be further improved. As a result, the fluidity of the toner can be more effectively improved, so that the uniformity of the toner coat over the entire area of the developing sleeve is improved, and a high image density can be maintained even at the end of the image. In particular, even when the toner is agitated and fed to the developing sleeve in the toner container, the toner has a good fluidity, so that the toner is sufficiently supplied to the developing sleeve and no development problem occurs.

In the present invention, the polypropylene wax preferably has an acid value of 1 to 30 mgKOH / g,
More preferably, it is 1 to 15 mgKOH / g, and still more preferably 1 to 10 mgKOH / g.

If the acid value is less than 1 mgKOH / g, it is difficult to obtain sufficient dispersibility of the wax in the toner. If the acid value exceeds 30 mgKOH / g, the cohesiveness between the waxes becomes strong, and the fluidity and developability of the toner decrease.

In the present invention, the polypropylene wax preferably has an endothermic peak measured by DSC of 130 ° C. or less. When the endothermic peak is 130 ° C. or lower, the softening point of the toner decreases, and the dispersibility of the magnetic material improves.

In the present invention, the content of the ethylene component in the polypropylene wax is 3% by weight or more, preferably 3 to 20% by weight, more preferably 3 to 10% by weight.
It is preferred that

When the content of the ethylene component is 3% by weight or more, the crystallinity of the wax is reduced, the dispersibility of the wax in the toner is improved, and the wax is used as a plasticizer for the binder resin. It works and the dispersibility of the magnetic material is further improved.

Examples of the polypropylene wax used in the present invention include a homopolymer of propylene and a copolymer of propylene and another olefin (especially ethylene).

The acid monomer used for modifying the polypropylene wax used in the present invention preferably contains at least one of a carboxyl group, a carboxylic anhydride group and a carboxylate group. Methacrylic acid, α-ethylacrylic acid, acrylic acid such as crotonic acid and its α- or β-alkyl derivative, fumaric acid, maleic acid, unsaturated dicarboxylic acid such as citraconic acid and its monoester derivative or anhydride, These acid monomers can be used alone or as a mixture.

In particular, a polypropylene wax modified with an acid monomer selected from at least one of maleic acid, maleic acid half ester, and maleic anhydride is preferable.

The polypropylene wax preferably has a weight-average molecular weight of 50,000 or less. Further, 0.5 to 2 parts by weight based on 100 parts by weight of the binder resin in the magnetic toner particles.
It is preferably contained in an amount of 0 parts by weight.

When the content of the polypropylene wax is 20
When the amount is larger than the weight part, the chargeability of the toner deteriorates,
If the amount is less than 0.5 part by weight, the effect of the wax is not exhibited.

In the present invention, a wax having no acid value can be used in combination with a wax having an acid value. The wax component having no acid value preferably has a weight average molecular weight of 50,000 or less, and more preferably 0.5 to 20 parts by weight based on 100 parts by weight of the binder resin in the magnetic toner particles. .

In the present invention, the magnetic toner may further contain conventionally known pigments or dyes such as carbon black and copper phthalocyanine as coloring materials.

In the present invention, the magnetic toner may optionally contain a charge control agent. In the case of a negatively chargeable toner, a negative charge controlling agent such as a metal complex salt of a monoazo dye or a metal complex salt of salicylic acid, alkylsalicylic acid, dialkylsalicylic acid or naphthoic acid is used.

In the case of a positively chargeable toner, a positive charge control agent such as a nigrosine compound or an organic quaternary ammonium salt is used.

In the present invention, the magnetic toner preferably contains an inorganic fine powder or a hydrophobic inorganic fine powder mixed with the magnetic toner particles. As the inorganic fine powder, for example, silica fine powder or titanium oxide fine powder is preferably used alone or in combination.

The silica fine powder used in the present invention includes both dry silica called fumed silica or fumed silica produced by vapor phase oxidation of a silicon halide and so-called wet silica produced from water glass. Although it can be used, fumed silica having few silanol groups on the surface and inside and having no production residue is preferable.

Further, the silica fine powder used in the present invention is preferably subjected to a hydrophobic treatment. The hydrophobic treatment is provided by chemically treating with a treating agent such as an organosilicon compound which reacts or physically adsorbs with the silica fine powder. A preferred method is to treat the dry silica fine powder produced by the vapor phase oxidation of the silicon halide compound with a silane coupling agent and then treat it with an organosilicon compound such as silicone oil, or simultaneously with the treatment with a silane coupling agent. A method of treating with an organosilicon compound such as silicone oil may be used.

Examples of the silane coupling agent used in the hydrophobic treatment include hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, and allylphenyl. Dichlorosilane, benzylmethylchlorosilane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilanemethylcaptan, trimethylsilylmercaptan, triorganosilyl acrylate, Vinyldimethylacetoxysilane, dimethylethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisiloxane, 1, Examples include 3-divinyltetramethyldisiloxane and 1,3-diphenyltetramethyldisiloxane.

Examples of the organosilicon compound used for the hydrophobizing treatment include silicone oil. As a preferred silicone oil, one having a viscosity at 25 ° C. of about 30 to 1,000 centistokes is used. For example, dimethyl silicone oil, methylphenyl silicone oil, α-methylstyrene-modified silicone oil, chlorophenyl silicone oil, and fluorine-modified silicone oil are preferred.

Examples of the method of silicone oil treatment include a method in which silica fine powder treated with a silane coupling agent and silicone oil are directly mixed using a mixer such as a Henschel mixer, and a method in which silicone oil is injected into silica as a base. Or a method in which silicone oil is dissolved or dispersed in an appropriate solvent, mixed with a base silica fine powder, and the solvent is removed.

Further, a preferred form of the hydrophobizing treatment of the silica fine powder used in the present invention is a method prepared by treating with dimethyldichlorosilane, then with hexamethyldisilazane, and then with silicone oil. Can be

As described above, it is preferable to treat the silica fine powder with two or more silane coupling agents and then treat it with oil, since the degree of hydrophobicity can be effectively increased.

The hydrophobic treatment of the above silica fine powder and the oil treatment of the titanium oxide fine powder can be used in the present invention, and it is preferable as in the case of silica.

The inorganic fine powder or the hydrophobic inorganic fine powder mixed with the magnetic toner particles is used in an amount of 0.1 to 5.0 parts by weight (preferably 0.1 to 5.0 parts by weight) based on 100 parts by weight of the magnetic toner particles.
3.0 parts by weight).

In the present invention, an external additive other than the silica fine powder may be added to the magnetic toner, if necessary.

The external additives include, for example, a charge auxiliary, a conductivity-imparting agent, a fluidity-imparting agent, an anti-caking agent,
Examples thereof include resin fine particles and inorganic fine particles that function as a release agent, a lubricant, and an abrasive at the time of hot roll fixing.

The resin fine particles preferably have a number average particle diameter of 0.03 to 1.0 μm based on a measuring method described later. As the polymerizable monomer constituting the resin,
Styrene, o-methylstyrene, m-methylstyrene,
Styrene-based monomers such as p-methylstyrene, p-methoxystyrene and p-ethylstyrene; acrylic acid; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, n-propyl acrylate, acrylic N-octyl acid, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate,
Acrylates such as 2-chloroethyl acrylate and phenyl acrylate; methacrylic acid; methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, methacryl Methacrylates such as dodecyl acrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate; other monomers such as acrylonitrile; methacrylonitrile; and acrylamide. No.

As a method for polymerizing resin fine particles using the above monomers, suspension polymerization, emulsion polymerization, and leap-free polymerization can be used, and more preferably, particles obtained by soap-free polymerization are preferable.

In particular, the resin fine particles having the above-described characteristics can be fused to a drum when a contact charging member such as a roller, a brush, or a blade is used as a charging member for primary charging a latent image carrier such as a photosensitive drum. A great effect can be brought about in suppressing the noise.

Examples of the inorganic fine particles include abrasives such as zinc stearate or cerium oxide, silicon carbide and strontium titanate (preferably strontium titanate), and fluidity imparting agents such as titanium oxide and aluminum oxide ( Above all, hydrophobic ones are preferable), and anti-caking agents, for example, a conductivity-imparting agent such as carbon black, zinc oxide, antimony oxide and tin oxide, and white and black fine particles of opposite polarity are used in small amounts as developability improvers. It can also be used.

As described above, the magnetic toner may be used by externally adding an external additive to the magnetic toner particles. However, as is apparent from the method for measuring the particle size distribution of the magnetic toner described below, the particle size distribution of the magnetic toner is measured for particles having a particle size of 2 μm or more. Since it is smaller than the target and the amount of external addition is small, the particle size distribution before and after externally adding the external additive to the magnetic toner particles does not substantially change.

To prepare a magnetic toner for developing an electrostatic image according to the present invention, a magnetic iron oxide and a vinyl or non-vinyl thermoplastic resin, if necessary, a pigment or dye as a colorant, Control agent, other additives and the like are sufficiently mixed by a mixer such as a ball mill, and then heated,
Melting, kneading and kneading using a hot kneader such as a kneader or extruder to disperse or disperse the magnetic iron oxide and the pigment or dye in the resin, then solidify by cooling, pulverize and strictly The magnetic toner according to the present invention can be obtained by performing an appropriate classification.

As another method for obtaining the magnetic toner according to the present invention, the toner can be produced by a polymerization method. This polymerization toner uniformly dissolves or disperses a polymerizable monomer, a magnetic iron oxide, and a polymerization initiator (and, if necessary, a crosslinking agent, a charge control agent and other additives) to form a monomer composition. After preparation, the monomer composition or a pre-polymerized version of the monomer composition is dispersed in a continuous phase (eg, water) containing a dispersion stabilizer using a suitable stirrer, and simultaneously polymerized. The reaction is carried out to obtain toner particles having a desired particle size. When the magnetic iron oxide used in the present invention is used in the polymerization method, it is preferable to perform a hydrophobic treatment in advance.

Next, the structure and production method of the magnetic iron oxide used in the present invention will be described.

The silicon element and other metal elements in the magnetic iron oxide used in the present invention are basically present inside and on the surface of the magnetic iron oxide.

The distribution of the internal metal elements of the magnetic iron oxide shown in Examples of the present invention was examined by an acid dissolution method. As a result, the silicon element and other metal elements were present from the center of the magnetic iron oxide and were directed toward the surface. It was found that the content increased in a gradient manner.

The magnetic iron oxide containing a silicon element according to the present invention is produced, for example, by the following method. A predetermined amount of Mn, Zn, Ni, Cu, Co, Cr, Cd,
After adding one or more metal salts and silicates selected from Al, Sn, and Mg, an alkali such as sodium hydroxide is added to the iron component in an equivalent amount or more to prepare an aqueous solution containing ferrous hydroxide. I do. Adjust the pH of the prepared aqueous solution to pH 7
Air is blown in while maintaining the above (preferably pH 8 to 10), and the ferrous hydroxide is oxidized while the aqueous solution is heated to 70 ° C. or higher, and a seed crystal serving as a core of magnetic iron oxide particles is first generated. I do.

Next, an aqueous solution containing the first equivalent of ferrous sulfate based on the amount of the alkali previously added is added to the slurry liquid containing the seed crystals. The reaction of ferrous hydroxide is promoted while blowing air while maintaining the pH of the solution at 6 to 10, and magnetic iron oxide particles are grown around the seed crystal. The pH of the solution shifts to the acidic side as the oxidation reaction proceeds, but it is preferable that the pH of the solution is not less than 6. It is preferable that the pH of the solution is adjusted at the end of the oxidation reaction so that a predetermined amount of another metal compound is unevenly distributed on the surface layer and the surface of the magnetic iron oxide particles.

Examples of the silicate used for the addition include sodium silicate and potassium silicate. As metal salts other than iron used for the addition, sulfates, nitrates and chlorides can be used.

As the ferrous salt, iron sulfate generally produced as a by-product in the production of titanium sulfate, iron sulfate produced as a by-product of washing the surface of a copper plate, and iron chloride can be used. .

The method for producing magnetic iron oxide by the aqueous solution method generally uses an iron concentration of 0.5 to 2 mol / liter in view of preventing an increase in viscosity during the reaction and the solubility of iron sulfate. Generally, the lower the concentration of iron sulfate, the smaller the particle size of the product tends to be. At the time of the reaction, the larger the amount of air and the lower the reaction temperature, the more easily the particles are atomized.

According to the above-mentioned production method, when observed with a transmission electron microscope photograph, the magnetic iron oxide particles containing a silicate element and another kind of metal element were formed into a spherical shape mainly formed of a curved surface having no plate-like surface. It is preferable to produce magnetic iron oxide composed of particles and containing almost no octahedral particles, and use the magnetic iron oxide in a magnetic toner.

The method for measuring various physical property data in the present invention will be described in detail below.

(1) Amount of Metal Element In the present invention, the content (based on the iron element) of the metal element other than iron in the magnetic iron oxide, the dissolution rate of the iron element, and the metal other than iron relative to the dissolution rate of the iron element The content of the element can be determined by the following method. For example, 5
Put about 3 liters of deionized water in a liter beaker and heat in a water bath to 45-50 ° C. About 25 g of magnetic iron oxide slurried with about 400 ml of deionized water is added to the 5 liter beaker with the deionized water while washing with about 300 ml of deionized water.

Next, while maintaining the temperature at about 50 ° C. and the stirring speed at about 200 rpm, a special grade hydrochloric acid or a mixed acid of hydrochloric acid and hydrofluoric acid is added to start dissolution. At this time, the hydrochloric acid aqueous solution is about 3N. Approximately 20m several times from the start of dissolution until it is completely dissolved and transparent
Sample 1 and filter through a 0.1 μm membrane filter to collect the filtrate. Filter the filtrate to plasma emission spectroscopy (IC
By P), the iron element and the metal element other than the iron element are quantified.

The dissolution rate of iron element for each sample is calculated by the following equation.

[0132]

[Outside 1]

The content of the metal element other than the metal element for each sample is calculated by the following equation.

[0134]

[Outside 2]

The total content A of the metal element other than the iron element in the magnetic iron oxide corresponds to the concentration of the metal element per unit weight of the magnetic iron oxide (mg / l) after being completely dissolved.

The contents B and C of the metal elements other than the iron element of the magnetic iron oxide are determined when the dissolution rate of the magnetic iron oxide is 20% or
%, It corresponds to the concentration (mg / l) of metal elements other than iron element per unit weight of the detected magnetic iron oxide.

(2) Density of Magnetic Iron Oxide The bulk density of the magnetic iron oxide particles in the present invention is determined according to JIS-K
It measured according to the pigment test method of -5101.

(3) Sphericity of Magnetic Iron Oxide The sphericity of magnetic iron oxide in the present invention is calculated as follows.

[0139]

[Outside 3]

The sphericity (φ) was measured using an electron microscope (Hitachi / H-700H) using a magnetic iron oxide sample treated on a copper mesh of a collodion film at an applied voltage of 100 kV.
The image is photographed at 0000 ×, the printing magnification is 3 ×, and the final magnification is 30000 ×. Thus, the shape is observed, 100 magnetic iron oxide particle specimens are randomly selected, the maximum length and the minimum length are measured, and the calculated values are averaged.

(4) Number Average Particle Size of Magnetic Iron Oxide From a transmission electron micrograph (magnification: 30,000 times), 100 particles on the photograph were randomly selected, the particle diameter was measured, and the average value was used as the number average particle size. Diameter.

(5) Particle Size Distribution of Magnetic Toner The toner particle size distribution of the present invention is measured using a Coulter Counter TA-II or Coulter Multisizer (manufactured by Coulter Co.). The electrolyte is 1% using primary sodium chloride. Adjust the aqueous NaCl solution. For example, IS
OTON R-II (manufactured by Coulter Scientific Japan) can be used. As a measuring method, a surfactant, preferably an alkylbenzene sulfonate, is used as a dispersant in 100 to 150 ml of the electrolytic aqueous solution.
Add 1 to 5 ml, and further add 2 to 20 mg of the measurement sample.
The electrolyte in which the sample is suspended is subjected to dispersion treatment for about 1 to 3 minutes using an ultrasonic disperser, and the volume and number of toner particles having a size of 2 μm or more are measured using the above-mentioned measuring device using an aperture of 100 μm as an aperture. Distribution was calculated.

Then, the weight-based weight average diameter (D4) and the volume average particle diameter (D4) obtained from the volume distribution according to the present invention were obtained.
v) (The median value of each channel is set as a representative value for each channel.) Content of magnetic toner particles having a particle diameter of 12.7 μm or more determined from volume distribution and magnetic toner particles having a particle diameter of less than 4.0 μm determined from number distribution. I asked.

(6) Acid value of wax The acid value of the wax is determined by the following method.

<Sampling of Wax Component> 0.5 to 1.0 g of a toner sample was weighed, placed in a cylindrical filter paper (for example, No. 86R manufactured by Toyo Roshi Kabushiki Kaisha), and toluene 100 was used as a solvent.
Soxhlet extraction was performed for 20 hours using 、 200 ml, and the soluble components eluted by the solvent were evaporated.
Vacuum dry at 100 ° C for several hours. To the obtained extract, 20 ml of chloroform is added, and the mixture is allowed to stand for 1 hour, then filtered through a membrane filter having a pore size of 0.45 μm and dried to obtain a wax component.

<Measurement of acid value>-Apparatus and apparatus Direct reading balance Erlenmeyer flask (200 ml) Measuring cylinder (100 ml) Microburet (10 ml) Electric heater-Reagent Xylene dioxane N / 10 caustic potassium standard methanol solution 1% phenolphthalein solution (Indicator) Measurement method 1 to 1.5 g of a wax is precisely weighed in an Erlenmeyer flask, 20 ml of xylene is added thereto, and the mixture is heated and dissolved. After dissolution, 20 ml of dioxane is added and titration is carried out as soon as possible with 1% phenolphthalein as an indicator with a methanolic solution of N / 10 caustic potassium while the solution does not become turbid or turbid. Perform a blank test at the same time. ·a formula

[0147]

[Outside 4] A: Number of ml of N / 10 caustic potassium standard methanol solution required for this test B: Number of ml of N / 10 caustic potassium standard methanol solution required for blank test f: Fact of N / 10 caustic potassium standard methanol solution
r S: sample (g)

(7) Endothermic peak of the wax by DSC measurement In the DSC measurement, the exchange of heat is measured and its behavior is observed. Therefore, from the measurement principle, a highly accurate internal heating type input compensation type differential scanning calorimeter is used. Need to measure. For example, DSC-7 manufactured by PerkinElmer can be used.

The measuring method is as described in ASTM D3418-82.
Perform according to. The DSC curve used in the present invention has a temperature rate of 10 ° C./min after the temperature is raised once and a pre-history is obtained.
A DSC curve measured when the temperature is lowered and raised in the temperature range of 0 to 200 ° C. is used. Endothermic peak temperature is DS
In the C curve, the peak temperature in the positive direction, that is, 0 when the differential value of the peak curve changes from positive to negative.
Say that

(8) Content of Ethylene Component in Wax The content of ethylene component in the wax can be measured by composition analysis using a nuclear magnetic resonance apparatus (13C ^- NMR).

Specifically, for example, the measurement can be performed under the following conditions using a 400 MHz EX400FT-NMR apparatus manufactured by JEOL Ltd. Measurement frequency: 100, 40 MHz Pulse condition: 5.0 μs (45 °) by DEPT method Data point: 32768 Delay time: 25 sec Frequency range: 10500 Hz Number of integration: 10,000 times Measurement temperature: 110 ° C. Sample: 200 mg of a measurement sample having a diameter of 10 mm The solution is prepared by adding benzene d ₆ / o-dichlorobenzene d ₄ (1/4) as a solvent in a sample tube and dissolving it in a thermostat at 110 ° C.

The content of the ethylene unit is calculated from the integrated value of the peak value based on the difference in chemical shift caused by the difference in the bond between the measured methine group and carbon in the molecule.

(9) Number average particle diameter of resin fine particles From an electron microscope enlarged photograph (× 10000) of resin fine particles, 100 particles having a particle diameter of 0.005 km or more were randomly selected, their diameters were measured, and the average was measured. The calculated value was defined as the number average particle diameter of the resin fine particles.

One preferred embodiment of the image tilt method of the present invention will be described with reference to FIG.

The surface of the OPC photosensitive drum 3 as an electrostatic latent image carrier is negatively charged by a contact charging member 11 comprising a charging roller as a primary charger, and is exposed to laser light.
Forming a digital latent image by image scanning, and a developing device 1 as a developing unit having a developing sleeve 6 as a toner carrying member including a urethane rubber elastic blade 8 and a magnet 15 installed in the counter direction. The latent image is reversal-developed with the negatively triboelectrically chargeable magnetic toner 13. Alternatively, an amorphous silicon photoreceptor is used as an electrostatic latent image holding member, the photoreceptor is charged to a positive polarity to form an electrostatic latent image, and regular development is performed using a negative frictionally chargeable magnetic toner.

The amount of toner charged in the developing device is usually 10
Although the amount is 0 to 900 g, the present invention can cope with a case where a large amount of magnetic toner of 1000 to 4000 g is filled as compared with the normal toner filling amount of the developing device.

An alternate bias, a pulse bias and / or a DC bias are applied to the developing sleeve 6 by the bias applying means 12. When the transfer paper P is conveyed and arrives at the transfer section, the transfer paper P is charged from the back surface (opposite to the photosensitive drum side) of the transfer paper P by the contact transfer member 4 including a transfer roller as a transfer means, so that the transfer paper P is transferred onto the photosensitive drum surface Is electrostatically transferred onto the transfer paper P. Photosensitive drum 3
The transfer paper P separated from the transfer paper P is subjected to a fixing process for fixing a toner image on the transfer paper P by a heating and pressing fixing device having a heating roller 21 having a heating unit 20 and a pressure roller 22 therein.

The magnetic toner remaining on the photosensitive drum 3 after the transfer step is removed by the cleaning device 14 having the cleaning blade 7. Photosensitive drum 3 after cleaning
Is removed by the erase exposure 10, and the process starting from the charging process by the primary charger 11 is repeated again.

The electrostatic latent image holder (photosensitive drum) has a photosensitive layer and a conductive substrate, and moves in the direction of the arrow. The non-magnetic cylindrical developing sleeve 6 serving as the toner carrier rotates in the developing section so as to advance in the same direction as the surface of the electrostatic latent image holding member. Inside the non-magnetic cylindrical developing sleeve 6, a multi-pole permanent magnet 15 (magnet roll) as a magnetic field generating means is arranged so as not to rotate. The magnetic toner 13 in the developing device 1 is applied on the developing sleeve 6, and the magnetic toner particles are given a negative triboelectric charge by friction between the surface of the developing sleeve 6 and the magnetic toner particles. Further, by disposing the elastic blade 8, the thickness of the toner layer is regulated to be thin (30 μm to 300 μm) and uniform, so that the development is performed with the photosensitive drum 3 in the developing section, which is the area where the photosensitive drum 3 faces the developing sleeve 6. A toner layer thinner than the gap between the sleeves 6 is formed so as to be in non-contact. The rotational speed of the developing sleeve 6 is adjusted so that the surface speed of the toner carrier is substantially equal to or close to the speed of the surface of the electrostatic latent image holding member.

An AC bias or a pulse bias may be applied to the developing sleeve 6 by the bias means 12.
This AC bias is f 200 to 4,000 Hz, Vp
It is preferable that p is 500 to 3,000 V.

When the magnetic toner is transferred from the toner carrier to the electrostatic latent image carrier in the developing portion, the electrostatic force on the surface of the electrostatic latent image carrier that holds the electrostatic latent image and the AC bias or pulse bias are applied. By the action, the magnetic toner is transferred to the electrostatic latent image holding member side.

A plurality of components such as the electrostatic latent image holding member such as the photosensitive drum, the developing device, the primary charging means, and the cleaning means are integrally combined as an apparatus unit to constitute a process cartridge. This process cartridge may be detachably mounted to the apparatus main body. For example, a process cartridge is formed by integrally supporting the primary charging unit and the developing device together with the photosensitive drum,
A single unit that can be attached to and detached from the apparatus main body may be configured to be detachably attached using a guide unit such as a rail of the apparatus main body. At this time, the above-described process cartridge may be provided with a cleaning unit.

FIG. 2 shows an embodiment of the process cartridge of the present invention. In the present embodiment, a developing device 1, a drum-like electrostatic latent image holding member (photosensitive drum) 3, a cleaner 1
4. A process cartridge 18 in which the primary charger 11 is integrated is exemplified.

In the process cartridge, when the magnetic toner 13 in the developing device 1 runs out, the cartridge is replaced with a new cartridge.

In this embodiment, the developing device 1 uses the magnetic toner 1
3, a predetermined electric field is formed between the photosensitive drum 3 and the developing sleeve 6 at the time of development, so that the developing process is preferably performed. The distance between them is very important. In this embodiment, the center is set to, for example, 300 μm, and the adjustment is performed so that the error becomes ± 20 μm.

In the process cartridge shown in FIG. 2, the developing device 1 includes a toner container 2 for storing the magnetic toner 13 and the magnetic toner 13 in the toner container 2 facing the electrostatic latent image holder 3 from the toner container 2. And a magnetic toner carried on the developing sleeve 6 and conveyed to the developing area to a predetermined thickness, and a toner thin layer is formed on the developing sleeve 6. An elastic blade 8 as a toner layer thickness regulating member for forming a layer.

The developing sleeve 6 can have any structure. Usually, it is composed of a non-magnetic developing sleeve 6 having a magnet 15 built therein. The developing sleeve 6 may be a cylindrical rotating body as shown. It is also possible to adopt a belt shape that moves in a circulating manner. The material is usually
Preferably, aluminum or SUS is used.

The elastic blade 8 is an elastic plate formed of a rubber elastic material such as urethane rubber or silicone rubber NBR; a metal elastic material such as phosphor bronze or a stainless steel plate; a resin elastic material such as polyethylene terephthalate or high-density polyethylene. Be composed. The elastic blade 8 is in contact with the developing sleeve 6 by the elasticity of the member itself, and is fixed to the toner container 2 by a blade supporting member 9 made of a rigid body such as iron. It is preferable that the elastic blade 8 abuts on the developing sleeve 6 carrying the magnetic toner at a linear pressure of 5 to 80 g / cm in one counter direction with respect to the rotation direction of the developing sleeve 6.

As the contact charging member, a blade-shaped charging blade can be used instead of the above-described charging roller.

When the image forming method of the present invention is applied to a facsimile printer, the light image exposure L is an exposure for printing received data. FIG. 3 shows 1 in this case.
An example is shown in a block diagram.

The controller 31 controls the image reading section 30 and the printer 39. The whole controller 31 is CP
It is controlled by U37. The read data from the image reading unit is transmitted to the partner station through the transmission circuit 33. Data received from the partner station is sent to the printer 39 through the receiving circuit 32. Predetermined image data is stored in the image memory. The printer controller 38 is the printer 3
9 is controlled. 34 is a telephone.

The image received from the line 35 (image information from a remote terminal connected via the line) is demodulated by the receiving circuit 32, and then the CPU 37 performs a decoding process of the image information and sequentially executes the image memory 36 Is stored in Then, when the image of at least one page is stored in the memory 36,
The image of the page is recorded. The CPU 37 is a memory 3
6, one page of image information is read out and the combined one page of image information is sent to the printer controller 38. The printer controller 38 receives 1
When the image information of the page is received, the printer 39 is controlled to record the image information of the page.

The CPU 37 receives the next page during recording by the printer 39.

As described above, image reception and recording are performed.

[0175]

EXAMPLES The present invention will be described below in more detail with reference to production examples and examples.

In the examples, "part" and "%"
Means “parts by weight” and “% by weight” unless otherwise specified.

Production of Magnetic Iron Oxide 1: (Production Example 1) Sodium silicate was added to an aqueous ferrous sulfate solution so that the content of silicon element with respect to iron element was 1.8%. 0.6% content of zinc element
After adding zinc sulfate so as to obtain, an aqueous solution containing ferrous hydroxide was prepared by mixing 1.0 to 1.1 equivalents of a sodium hydroxide solution with respect to iron ions.

The pH of the aqueous solution is adjusted to pH 7 to 10 (for example, p
H9), while blowing air, 80 to 90
An oxidation reaction was carried out at a temperature of ° C. to prepare a chiller solution for generating seed crystals.

Next, an aqueous ferrous sulfate solution was added to this chiller solution so that the amount thereof became 0.9 to 1.2 equivalents relative to the initial alkali amount (sodium component of sodium silicate and sodium component of caustic soda). While maintaining the pH of the chiller at pH 6 to 10 (for example, pH 8), the oxidation reaction was promoted while blowing air, the pH was adjusted at the end of the oxidation reaction, and the silicate component and the zinc component were unevenly distributed on the surface of the magnetic iron oxide particles. . Wash the generated magnetic iron oxide particles by a usual method,
Filtration, drying, and subsequent crushing treatment were performed to obtain magnetic iron oxide A.

Table 1 shows the relationship between the dissolution amounts of the iron element, the silicon element and the other metal elements and the properties of the obtained magnetic iron oxide A.

(Production Examples 2 to 7) Addition amount of sodium silicate
Magnetic iron oxides B to G having the characteristics shown in Table 1 were obtained in the same manner as in Production Example 1, except that the addition amount of the other metal salt was changed as shown in Table 1.

(Comparative Production Example 1) Magnetic iron oxide a having the properties shown in Table 1 was obtained in the same manner as in Production Example 1 except that sodium silicate and zinc sulfate were not added.

(Comparative Production Example 2) To 100 parts of the magnetic iron oxide obtained in Comparative Production Example 1, 0.7 parts by weight of a fine silica powder was mixed with a Henschel mixer to obtain the characteristics shown in Table 1. Magnetic iron oxide b was obtained.

(Comparative Production Example 3) Addition amount of sodium silicate
Magnetic iron oxides c to j having the characteristics shown in Table 1 were obtained in the same manner as in Production Example 1, except that the addition amount of the other metal salt was changed as shown in Table 1.

[0185]

[Table 1]

Production of Toner I: (Example 1) Styrene-n-butyl acrylate copolymer (copolymerization ratio = 70: 30, Mw = 300,000, Tg = 60 ° C.) 10
0 parts ・ 100 parts of magnetic iron oxide particles A of Production Example 1 ・ 2 parts of negative charge control agent represented by the following formula

[0187]

[Outside 5] ・ 3 parts of low molecular weight polypropylene

The above mixture was melt-kneaded with a twin-screw extruder heated to 140 ° C., and the cooled kneaded material was coarsely pulverized by a hammer mill, and the coarsely pulverized product was finely pulverized by a jet mill. Was classified with a fixed wall type air classifier to produce a classified powder. Furthermore, the resulting classified powder Coanda effect a multi-division classifier utilizing (Nittetsu Mining Co., Ltd. Elbow Jet classifier) ultrafine and coarse powder simultaneously strictly classified remove the weight average particle diameter (D ₄ ) 6.7 μm, volume average particle diameter (D ₁ ) 5.25 μm, content 0.2% of magnetic toner particles having a particle diameter of 12.7 μm or more, and particle diameter of less than 4.0 μm (particle diameter of 2.0 μm or more. (Less than 0 μm) to obtain negatively chargeable magnetic toner particles having a content of 20.5% of magnetic toner particles.

100 parts of the magnetic toner particles, 1.2 parts of hydrophobic silica fine powder (BET 300 m ² / g) treated with dimethyldichlorosilane, treated with hexamethyldisilazane, and then treated with dimethylsilicone oil, Negatively-chargeable magnetic toner 1 was prepared by mixing 0.08 parts of styrene-acrylic fine particles (average particle diameter 0.05 μm) obtained by soap-free polymerization with a Henschel mixer.

(Image Output Test) An image forming apparatus shown in FIG. 1 in which a laser beam printer 930 made by Canon was modified from 24 sheets / minute to 32 sheets / minute was used, and 1700 g of toner could be filled in a cartridge. The remodeled process cartridge shown in FIG. 2 was filled with 1700 g of the above magnetic toner 1. The process cartridge filled with the externally added magnetic toner was mounted on the image forming apparatus main body. The process speed at this time is 1
45 mm / sec. Met.

The primary charging was -700 V, the gap was set without contact between the photosensitive drum and the magnetic toner layer on the developing sleeve (including the magnet), and an AC bias (f = 2000 Hz, V
pp = 1600 V) and DC bias (V _DC = −500)
V) to the developing sleeve while applying _VL to -150.
V, the electrostatic latent image was developed to form a magnetic toner image on the OPC photoconductor.

The magnetic toner image formed on the OPC photoreceptor was transferred to plain paper at the above-mentioned positive transfer potential, and the plain paper having the magnetic toner image was fixed through a heating / pressing roller fixing device.

At this time, the surface temperature of the heating roller of the heating and pressing roller fixing device was set at 190 ° C., and the total pressure between the heating roller and the pressing roller was set at 30 kg.

Under the above set conditions, under a high temperature and high humidity environment (3
2.5 ° C, 85% RH) and low temperature and low humidity environment (10 ° C,
2 sheets / 20 sec. A printout test was performed on 30,000 sheets continuously at a printing speed of, and the obtained images were evaluated for the following items.

In a high-temperature, high-humidity environment, 15,000
After performing the image formation test, the sample was allowed to stand for 2 days under the same environment, and a 15,000 image formation test was further performed.

(1) Image Density Evaluation was made based on the image density of an image printed on ordinary plain paper for copying machines (filling amount: 75 g / m ² ). The image density was measured using a Macbeth reflection densitometer (manufactured by Macbeth).
The relative density with respect to the printout image of the white background portion where the document density was 0.00 was measured.

(2) In-page image density uniformity In-page image density uniformity was determined from the difference between the maximum and minimum image density values in the printout image.

(3) The whiteness (D _r ) of the transfer paper before printing and the whiteness (D _S ) of the transfer paper after printing solid white, measured by a fogging reflectometer (manufactured by Tokyo Denshoku Co., Ltd.). (D _S -D _r )
Fog was calculated. The environment in which the image is formed is low temperature and low humidity (15 ° C., 10 RH), and the print mode is 2 sheets / 20 sec. And

(4) Image Quality The checker pattern shown in FIG. 4 was printed out, and the dot reproducibility was evaluated based on the following evaluation criteria.

(Evaluation Criteria) Rank 1: Very good (2 or less defects / 100) Rank 2: Good (3 to 5/100 defects) Rank 3: Normal (6 to 10/100 defects) Rank 4: Bad (missing 11 or more / 100)

Table 2 shows the evaluation results.

(Examples 2 to 7) Magnetic toners 2 to 7 of Examples 2 to 7 were obtained in the same manner as in Example 1 except that the magnetic iron oxides B to G of Production Examples 2 to 7 were used. . Evaluation was performed in the same manner as in Example 1 using the obtained magnetic toners 2 to 7. Table 2 shows the evaluation results.

(Comparative Examples 1 to 10) Comparative Production Examples 1 to 1
Magnetic toners 8 to 17 were produced and evaluated in the same manner as in Example 1 except that magnetic iron oxides a to j of 0 were used. Table 2 shows the evaluation results.

[0204]

[Table 2]

Production of Magnetic Iron Oxide: (Production Example 8) Sodium silicate was added to an aqueous ferrous sulfate solution so that the content ratio of silicon element to iron element was 1.5%. 0.5% zinc element content
After adding zinc sulfate so as to obtain, an aqueous solution containing ferrous hydroxide was prepared by mixing 1.0 to 1.1 equivalents of a sodium hydroxide solution with respect to iron ions.

The pH of the aqueous solution is adjusted to pH 7 to 10 (for example, p
H9), while blowing air, 80 to 90
An oxidation reaction was performed at a temperature of 0 ° C. to prepare a slurry liquid for generating seed crystals.

Next, an aqueous ferrous sulfate solution was added to this chiller solution so as to have an equivalent amount of 0.9 to 1.2 equivalents based on the initial alkali amount (sodium component of sodium silicate and sodium component of caustic soda). While maintaining the pH of the solution at 6 to 10 (for example, pH 8), the oxidation reaction is promoted while blowing air, and the pH is adjusted at the end of the oxidation reaction.
Silicic acid components and zinc components were unevenly distributed on the surface of the magnetic iron oxide particles. The resulting magnetic iron oxide particles were washed, filtered, and dried by a conventional method, and then subjected to a crushing treatment to obtain magnetic iron oxide AA.

Table 3 shows the relationship and characteristics of the amounts of iron, silicon and other metal elements dissolved in the obtained magnetic iron oxide AA.

(Production Examples 9 to 13) Tables 3 and 4 were prepared in the same manner as in Production Example 8 except that the amounts of sodium silicate and other metal salts were changed as shown in Table 3. Magnetic iron oxides BB to FF having characteristics were obtained.

(Comparative Production Example 11) A magnetic iron oxide aa having the properties shown in Table 3 was obtained in the same manner as in Production Example 8, except that sodium silicate and zinc sulfate were not added.

(Comparative Production Example 12) To 100 parts of the magnetic iron oxide obtained in Comparative Production Example 11, 0.7 part of a silica derivative was mixed with a Henschel mixer, and had the properties shown in Table 3. Magnetic iron oxide bb was obtained.

(Comparative Production Example 13) The characteristics shown in Table 3 were the same as in Production Example 8 except that the addition amount of sodium silicate and the addition amount of the other metal salt were changed as shown in Table 3. Of magnetic iron oxides cc to gg were obtained.

[0213]

[Table 3]

Production of Toner II: (Example 8) Styrene-n-butyl acrylate copolymer (copolymerization ratio = 70: 30, Mw = 280,000, Tg = 59 ° C.) 10
0 parts-95 parts of magnetic iron oxide particles AA of Production Example 8-2 parts of a negative charge control agent represented by the following formula

[0215]

[Outside 6] 3 parts of acrylic acid-modified propylene-ethylene copolymer wax (acid value: 11.0 mgKOH / g, endothermic peak of DSC: 128 ° C., ethylene content: 6% by weight)

The above mixture was melt-kneaded with a twin-screw extruder heated to 140 ° C., and the cooled kneaded material was coarsely ground with a hammer mill, and the coarsely ground material was finely ground with a jet mill. Was classified with a fixed wall type air classifier to produce a classified powder. Furthermore, the resulting classified powder Coanda effect a multi-division classifier utilizing (Nittetsu Mining Co., Ltd. Elbow Jet classifier) ultrafine and coarse powder simultaneously strictly classified remove the weight average particle diameter (D ₄ 18.) 6.8 μm, volume average particle diameter (D ₁ ) 5.37 μm, content 0.1% of magnetic toner particles having a particle diameter of 12.7 μm or more, and content of magnetic toner particles having a particle diameter of less than 4.0 μm 7% of negatively chargeable magnetic toner particles were obtained.

100 parts of the magnetic toner particles, 1.2 parts of hydrophobic silica fine powder (BET 300 m ² / g) treated with dimethyldichlorosilane, treated with hexamethyldisilazane, and then treated with dimethylsilicone oil, 0.08 parts of styrene-acrylic fine particles (average particle diameter: 0.05 μm) obtained by soap-free polymerization were mixed with a Henschel mixer to prepare a negatively chargeable magnetic toner 18.

(Image Output Test) A Canon laser beam printer Laser Shot 430 (8 sheets /
), The toner supply state onto the sleeve and the image were evaluated. A printout test was performed by the following method using the image forming apparatus shown in FIG. 1 and the process cartridge shown in FIG. In this printout test,
This is performed as an extreme simulation of the fact that the toner is offset in the cartridge when the process cartridge is transported for a long time. Fill the process cartridge with 100 g of toner.・ Set up the process cartridge so that the developing sleeve in the cartridge is perpendicular to the ground, and drop the process cartridge 10 times from a height of about 10 cm onto a table on which a cushioning material such as cloth is laid, without vigor. . In the state where the process cartridge is dropped (the process cartridge is set up) for the tenth time, the process cartridge is left for 2 days in an environment where a printout test is performed.

The primary charge is -650 V, the gap is set in a non-contact manner between the photosensitive drum and the magnetic toner layer on the developing sleeve (including magnets), and an AC bias (f = 1800 Hz, V
pp = 1200 V) and DC bias (V _DC = −400)
V) is applied to the developing sleeve while _VL is -130.
V, the electrostatic latent image was developed to form a magnetic toner image on the OPC photoconductor.

The magnetic toner image formed on the OPC photoreceptor was transferred to plain paper at the above-mentioned positive transfer potential, and the plain paper having the magnetic toner image was fixed through a heating and pressing roller fixing device.

At this time, the surface temperature of the heating roller of the heating and pressing roller fixing device was set at 180 ° C., and the total pressure between the heating roller and the pressing roller was set at 7.5 kg.

Under the above set conditions, under a high temperature and high humidity environment (3
2.5 ° C, 85% RH) and low temperature and low humidity environment (15 ° C,
A printout test was performed using a process cartridge left for 2 days in an environment of 10% RH), and the obtained image was subjected to the same procedures as in Example 1 to obtain (1) image density,
Each item of (2) image density uniformity within a page, (3) fog, and (4) image quality was evaluated.

Table 5 shows the evaluation results.

(Examples 9 to 12) Except that the magnetic iron oxides BB to EE of Production Examples 9 to 12 and the wax shown in Table 4 were used, the negative charging of Examples 9 to 12 was performed in the same manner as in Example 8. Magnetic toners 19 to 22 were obtained. The obtained magnetic toners 19 to 22 were evaluated in the same manner as in Example 8. Table 5 shows the evaluation results.

(Example 13) Magnetic iron oxide F of Production Example 13
F and the waxes shown in Table 4 were used, and an unmodified polypropylene wax (99% or more of propylene component, D
Negatively-chargeable magnetic toner 23 was obtained in the same manner as in Example 8, except that 4 parts of an endothermic peak of SC (137 ° C.) was added. The obtained magnetic toner 23 was evaluated in the same manner as in Example 8. Table 5 shows the evaluation results.

Example 14 A magnetic toner 24 of Example 14 was obtained in the same manner as in Example 8, except that the wax shown in Table 4 was used. The obtained magnetic toner 24 was used in Example 8.
The evaluation was performed in the same manner as described above. Table 5 shows the evaluation results.

Comparative Examples 11 to 17 Magnetic toners 25 to 31 were produced in the same manner as in Example 8 except that the magnetic iron oxides aa to gg of Comparative Production Examples 11 to 17 and the wax shown in Table 4 were used. evaluated. Table 5 shows the evaluation results.

[0228]

[Table 4]

[0229]

[Table 5]

[0230]

As described above, even when the magnetic toner of the present invention is used in a large-capacity toner developing device, the magnetic toner does not undergo fading development under low-temperature, low-humidity and high-temperature, high-humidity environments. Achieves high quality images, high developability, no fog, excellent image quality, and long-term durability.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of an image forming apparatus capable of performing an image forming method of the present invention.

FIG. 2 is a schematic explanatory view of a process cartridge of the present invention.

FIG. 3 is a block diagram showing a case where the image forming method of the present invention is applied to a printer of a facsimile machine.

FIG. 4 is an explanatory diagram of a checker pattern for testing the development characteristics of a magnetic toner.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Developing device 2 Toner container 3 Electrostatic latent image holding body (photosensitive drum) 4 Transfer means 5 Laser light or analog light 6 Toner carrier (developing sleeve) 7 Cleaning blade 8 Regulator blade 11 Primary charging means 12 Bias applying means 13 Magnetic toner 14 Cleaning means 15 Magnetic field generating means 18 Process cartridge 20 Heating body 21 Fixing roller 22 Pressure roller

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI G03G 9/08 375 (72) Inventor Tsutomu Onuma 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Invention ▲ Taka ▼ No Masao No.3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc.

Claims (90)

[Claims] 1. A magnetic toner comprising magnetic toner particles containing at least a binder resin and magnetic iron oxide, wherein the magnetic iron oxide is composed of Mn, Zn, N
One or more metal elements selected from the group consisting of i, Cu, Co, Cr, Cd, Al, Sn and Mg.
2 to 0.4% by weight, and further contains 0.1% of silicon element.
2 to 0.8% by weight, wherein the magnetic iron oxide contains the silicon element content B _Si present when the iron element dissolution rate of the magnetic iron oxide is up to 20% by weight and the magnetic iron oxide is present in the magnetic iron oxide. Ratio of the total silicon element to the _Si content (B
_Si / A _Si ) × 100 is 45 to 85%, and the ratio of the content C _Si of the silicon element and the content A _Si of the magnetic iron oxide present when the iron element dissolution rate of the magnetic iron oxide is up to 10% by weight ( C _Si / A
_Si ) × 100 is 35 to 70%, and the magnetic toner has a weight average particle size of 3.5 to 10.0 μm.
m, and the content of the magnetic toner particles having a particle diameter of 12.7 μm or more determined from the volume distribution is 0 to 30% by volume. 2. The magnetic iron oxide according to claim 1, wherein Mn, Zn, Ni, and Ni are present when the iron element dissolution rate of the magnetic iron oxide is up to 20% by weight.
Content B of one or more metal elements selected from the group consisting of Cu, Co, Cr, Cd, Al, Sn and Mg
_Metal and the ratio of the content A _Metal of the metal group element present in the magnetic iron oxide _{(B Metal / A Metal) ×} 10
0 is 40 to 100%.
3. The magnetic toner according to item 1. 3. The magnetic iron oxide according to claim 1, wherein M is based on iron element.
The n elements containing 0.7 to 2.0 wt%, and the content M _Mn of Mn element iron element dissolution percentage of the magnetic iron oxide is present in up to 20% by weight, the total present in the magnetic iron oxide The ratio (M _Mn / A _Mn ) × 100 of Mn element content to A _Mn is 50 to 90.
%. 3. The magnetic toner according to claim 1, wherein 4. The magnetic iron oxide according to claim 1, wherein Z
The n elements containing 0.2 to 0.8 wt%, and the content B _Zn of Zn element iron element dissolution ratio of the magnetic iron oxide is present in up to 20% by weight, the total present in the magnetic iron oxide the ratio between the content a _Zn of Zn element _{(B Zn / a Zn) ×} 100 is 40 to 1
The magnetic toner according to claim 1, wherein the content of the magnetic toner is 00%. 5. The magnetic iron oxide according to claim 1, wherein C is
the Cu element content B _Cu containing 0.01 to 0.8% by weight of the u element, and the iron element dissolution rate of the magnetic iron oxide is up to 10% by weight; 3. The magnetic toner according to claim 1, wherein a ratio (B _Cu / A _Cu ) × 100 of the Cu element content to A _Cu is 70 to 100%. 6. The magnetic iron oxide according to claim 1, wherein said magnetic iron oxide is N
The i element containing 0.1 to 0.6 wt%, and the content B _Ni of Ni element iron element dissolution ratio of the magnetic iron oxide is present in up to 20% by weight, the total present in the magnetic iron oxide Ni element content A _Ni ratio (B _Ni / A _Ni ) × 100 is 40 to 1
The magnetic toner according to claim 1, wherein the content of the magnetic toner is 00%. 7. The magnetic toner according to claim 1, wherein the magnetic iron oxide has a bulk density of 0.4 to 0.8 g / cm ³ . 8. The magnetic toner according to claim 1, wherein the magnetic iron oxide has a sphericity of 0.80 or more. 9. The magnetic iron oxide has a number average particle size of 0.0
The magnetic toner according to any one of claims 1 to 8, wherein the thickness is 5 to 1.00 µm. 10. The magnetic iron oxide has a number average particle size of 0.1.
2. The structure according to claim 1, wherein the thickness is 10 to 0.40 μm.
9. The magnetic toner according to any one of items 1 to 8. 11. The magnetic toner having a volume average particle size of 2.
The magnetic toner according to claim 1, wherein the magnetic toner has a thickness of 5 to 6.0 μm. 12. The magnetic toner according to claim 1, wherein the magnetic iron oxide contains 20 to 200 parts by weight of the magnetic iron oxide based on 100 parts by weight of the binder resin. Magnetic toner. 13. The magnetic toner according to claim 1, wherein the magnetic toner contains 30 to 150 parts by weight of the magnetic iron oxide based on 100 parts by weight of the binder resin. Magnetic toner. 14. The magnetic toner particles according to claim 1, wherein the magnetic toner particles further contain a hydrocarbon wax, an ethylene olefin polymer or an ethylene olefin copolymer as a fixing aid. The magnetic toner according to any one of the above. 15. The magnetic toner particles may contain 1 to 30 mg.
14. The composition according to claim 1, further comprising a polypropylene wax having an acid value of KOH / g.
The magnetic toner according to any one of the above. 16. The magnetic toner particles may contain 1 to 30 mg.
14. The composition according to claim 1, further comprising a polypropylene wax having an acid value of KOH / g.
The magnetic toner according to any one of the above. 17. The magnetic toner according to claim 15, wherein the wax contains an ethylene component in an amount of 3% by weight or more. 18. The wax has an ethylene component of 3 to 2 times.
The magnetic toner according to claim 15, wherein the magnetic toner is contained in an amount of 0% by weight. 19. The wax has an ethylene component of 3 to 1%.
The magnetic toner according to claim 15, wherein the magnetic toner is contained in an amount of 0% by weight. 20. The wax according to claim 1, wherein the wax is at least one selected from the group consisting of maleic acid, maleic acid half ester and maleic anhydride.
16. The magnetic toner according to claim 15, wherein the magnetic toner is modified with an acid monomer selected from at least one kind. 21. The magnetic toner according to claim 1, wherein the magnetic toner has a mixture of the magnetic toner particles and inorganic fine powder. 22. The magnetic toner according to claim 21, wherein the inorganic fine powder has been subjected to a hydrophobic treatment. 23. The method according to claim 21, wherein the inorganic fine powder comprises silica fine powder or titanium fine powder.
3. The magnetic toner according to 2. 24. The magnetic toner according to claim 21, wherein the silica fine powder is treated with a silane coupling agent and silicone oil. 25. The method according to claim 24, wherein the silica fine powder is treated with a silane coupling agent and then treated with a silicone oil, or simultaneously treated with a silane coupling agent and a silicone oil. 3. The magnetic toner according to item 1. 26. The magnetic toner, comprising:
The inorganic fine powder is added in an amount of 0.1 to 5.0 parts by weight to 00 parts by weight.
26. The composition according to claim 21, wherein the component has a weight part.
The magnetic toner according to any one of the above. 27. The magnetic toner according to claim 21, wherein the magnetic toner has a mixture having resin fine particles in addition to the magnetic toner particles and the inorganic fine powder. 28. A latent image forming step of forming an electrostatic latent image on an electrostatic latent image holder, and a step of carrying the electrostatic latent image held on the electrostatic latent image holder on a toner carrier. Developing a magnetic toner to form a toner image, wherein the magnetic toner has magnetic toner particles containing at least a binder resin and magnetic iron oxide; The magnetic iron oxide is composed of Mn, Zn, N based on the iron element.
One or more metal elements selected from the group consisting of i, Cu, Co, Cr, Cd, Al, Sn and Mg.
2 to 4.0% by weight, and further contains 0.1% of silicon element.
2 to 0.8% by weight, wherein the magnetic iron oxide contains the silicon element content B _Si present when the iron element dissolution rate of the magnetic iron oxide is up to 20% by weight and the magnetic iron oxide is present in the magnetic iron oxide. Ratio of the total silicon element to the _Si content (B
_Si / A _Si ) × 100 is 45 to 85%, and the iron dissolution rate of the magnetic iron oxide is up to 10% by weight. Silicon element content C _Si , the content C _Si and the content the ratio of the _{a Si (C Si / a Si} ) × 100 is 35 to 70%, magnetic toner has a weight average particle diameter of 3.5 to 10.0μ
m, and the content of magnetic toner particles having a particle diameter of 12.7 μm or more determined from a volume distribution is 0 to 30% by volume. 29. The magnetic iron oxide according to claim 1, wherein the magnetic iron oxide has an iron element dissolution rate of up to 20% by weight.
i, Cu, Co, Cr, Cd, Al, the content of the metal group element present in the content B _Metal and in magnetic iron oxide of at least one metallic element selected from the group consisting of Sn and Mg A _Metal and ratio (B _Metal / a _Metal) ×
The image forming method according to claim 28, wherein 100 is 40 to 100%. 30. The magnetic iron oxide contains 0.7 to 2.0% by weight of Mn element based on the iron element, and the iron dissolution rate of the magnetic iron oxide is up to 20% by weight. (B _Mn / A _Mn ) × 100 of the content B _Mn of the magnetic iron oxide to the content A _Mn of the total Mn present in the magnetic iron oxide is 50 to 90%.
30. The image forming method according to claim 28, wherein: 31. The magnetic iron oxide contains 0.2 to 0.8% by weight of Zn element based on the iron element, and the Zn element exists when the iron element dissolution rate of the magnetic iron oxide is up to 20% by weight. 29. The ratio (B _Zn / A _Zn ) × 100 of the content B _Zn of the content to the content A _Zn of all Zn elements present in the magnetic iron oxide is 40 to 100%. Or the image forming method according to 29. 32. The magnetic iron oxide according to claim 1, wherein said magnetic iron oxide contains 0.01 to 0.8% by weight of Cu element, and said magnetic iron oxide has a solubility of iron element of up to 10% by weight. 29. The ratio (B _Cu / A _Cu ) × 100 of the content B _Cu of the content to the content A _Cu of all Cu elements present in the magnetic iron oxide is 70 to 100%. Or 29
2. The image forming method according to 1., 33. The magnetic iron oxide, wherein the magnetic iron oxide contains 0.1 to 0.6% by weight of Ni element based on the iron element, and the iron element dissolution rate of the magnetic iron oxide is up to 20% by weight. 29. The ratio (B _Ni / A _Ni ) × 100 of the content B _Ni of the content of _Ni to the content A _Ni of all Ni elements present in the magnetic iron oxide is 40 to 100%. Or the image forming method according to 29. 34. The image forming method according to claim 28, wherein said magnetic iron oxide has a bulk density of 0.4 to 0.8 g / cm ³ . 35. The image forming method according to claim 28, wherein the magnetic iron oxide has a sphericity of 0.80 or more. 36. The magnetic iron oxide has a number average particle size of 0.1.
3. The thickness of the film is from 0.05 to 1.00 μm.
36. The image forming method according to any one of items 8 to 35. 37. The magnetic iron oxide has a number-average particle diameter of 0.1.
3. The structure according to claim 2, wherein the thickness is 10 to 0.40 μm.
36. The image forming method according to any one of items 8 to 35. 38. The magnetic toner having a volume average particle size of 2.
The image forming method according to any one of claims 28 to 37, wherein the thickness is 5 to 6.0 µm. 39. The magnetic toner according to claim 28, wherein the magnetic iron oxide contains 20 to 200 parts by weight of the magnetic iron oxide based on 100 parts by weight of the binder resin. Image forming method. 40. The magnetic toner according to claim 28, wherein the magnetic iron oxide contains 30 to 150 parts by weight of the magnetic iron oxide based on 100 parts by weight of the binder resin. Image forming method. 41. The magnetic toner according to claim 28, wherein the magnetic toner particles further contain a hydrocarbon wax, an ethylene-based olefin polymer or an ethylene-based olefin copolymer as a fixing aid. The image forming method according to any one of the above. 42. The magnetic toner particles may contain 1 to 30 mg.
The polypropylene wax having an acid value of KOH / g is further contained.
0. The image forming method according to any one of 0. 43. The magnetic toner particles may contain 1 to 30 mg.
The polypropylene wax having an acid value of KOH / g is further contained.
0. The image forming method according to any one of 0. 44. The image forming method according to claim 42, wherein said wax contains 3% by weight or more of an ethylene component. 45. The wax according to claim 35, wherein the ethylene component is 3 to 2 times.
43. The image forming method according to claim 42, wherein 0% by weight is contained. 46. The wax contains an ethylene component in an amount of 3 to 1.
43. The image forming method according to claim 42, wherein 0% by weight is contained. 47. The wax may comprise at least one of maleic acid, maleic acid half ester and maleic anhydride.
43. The image forming method according to claim 42, wherein the image forming method is modified with an acid monomer selected from at least one kind. 48. The image forming method according to claim 28, wherein the magnetic toner has a mixture of the magnetic toner particles and inorganic fine powder. 49. The image forming method according to claim 48, wherein the inorganic fine powder has been subjected to a hydrophobic treatment. 50. The inorganic fine powder comprises silica fine powder or titanium fine powder.
10. The image forming method according to item 9. 51. The image forming method according to claim 48, wherein the fine silica powder is treated with a silane coupling agent and silicone oil. 52. The silica fine powder, which is treated with a silane coupling agent and then treated with a silicone oil, or simultaneously treated with a silane coupling agent and a silicone oil. 2. The image forming method according to 1., 53. The magnetic toner, comprising:
The inorganic fine powder is added in an amount of 0.1 to 5.0 parts by weight to 00 parts by weight.
53. The device according to claim 48, wherein the component has a weight part.
The image forming method according to any one of the above. 54. The image forming method according to claim 48, wherein the magnetic toner has a mixture having resin fine particles in addition to the magnetic toner particles and the inorganic fine powder. 55. An electrophotographic photosensitive member is used as the electrostatic latent image holding member.
The image forming method according to any one of the above. 56. The image forming method according to claim 28, wherein the toner image formed on the electrostatic latent image holding member is transferred to a transfer material. 57. The image forming method according to claim 56, wherein the toner image transferred onto the transfer material is heat-fixed. 58. The surface of the electrostatic latent image holding member after transfer,
56. The cleaning device according to claim 56, wherein the cleaning is performed.
8. The image forming method according to item 7. 59. The magnetic toner is carried on a surface of a toner carrier that is spaced from the electrostatic latent image carrier, and the magnetic latent image carrier and the toner are carried on the surface of the toner carrier. A toner layer having a thickness smaller than the distance between the toner carrier and the toner carrier was formed. The image forming method according to any one of claims 28 to 58, wherein the electrostatic latent image on the electrostatic latent image holding member is developed by the magnetic toner of the toner layer. 60. The image forming method according to claim 59, wherein an AC bias or a pulse bias is applied to the toner carrier when developing the electrostatic latent image. 61. A process cartridge removably mounted on an image forming apparatus main body, wherein the process cartridge includes an electrostatic latent image holder for holding an electrostatic latent image and a developing unit for developing the electrostatic latent image. The magnetic toner has magnetic toner particles containing at least a binder resin and a magnetic iron oxide, and the magnetic iron oxide has a Mn based on an iron element. , Zn, N
One or more metal elements selected from the group consisting of i, Cu, Co, Cr, Cd, Al, Sn and Mg.
2 to 4.0% by weight, and further contains 0.1% of silicon element.
2 to 0.8% by weight, wherein the magnetic iron oxide contains the silicon element content B _Si present when the iron element dissolution rate of the magnetic iron oxide is up to 20% by weight and the magnetic iron oxide is present in the magnetic iron oxide. Ratio of the total silicon element to the _Si content (B
_Si / A _Si ) × 100 is 45 to 85%, and the ratio of the content C _Si of the silicon element and the content A _Si of the magnetic iron oxide in which the iron element dissolution rate of the magnetic iron oxide is up to 10% by weight ( C _Si / A
_Si ) × 100 is 35 to 70%, and the magnetic toner has a weight average particle size of 3.5 to 10.0 μm.
m, and a content of magnetic toner particles having a particle diameter of 12.7 μm or more determined from a volume distribution is 0 to 30% by volume. 62. The magnetic iron oxide, wherein Mn, Zn, N is present when the iron dissolution rate of the magnetic iron oxide is up to 20% by weight.
i, Cu, Co, Cr, Cd, Al, the content of the metal group element present in the content B _Metal and in magnetic iron oxide of at least one metallic element selected from the group consisting of Sn and Mg A _Metal and ratio (B _Metal / A _Metal ) × 1
63. The process cartridge according to claim 61, wherein 00 is 40 to 100%. 63. The magnetic iron oxide contains 0.7 to 2.0% by weight of Mn element based on the iron element, and the iron dissolution rate of the magnetic iron oxide is up to 20% by weight. (B _Mn / A _Mn ) × 100 of the content B _Mn of Pb and the content A _Mn of all Mn elements present in the magnetic iron oxide is 50 to 9
63. The process cartridge according to claim 61, wherein the amount is 0%. 64. The magnetic iron oxide contains 0.2 to 0.8% by weight of Zn element based on the iron element, and the Zn element is present when the iron element dissolution rate of the magnetic iron oxide is up to 20% by weight. 62. The ratio (B _Zn / A _Zn ) × 100 of the content B _Zn of the content to the content A _Zn of all Zn elements present in the magnetic iron oxide is 40 to 100%. 63. The process cartridge according to 62. 65. The magnetic iron oxide contains Cu element in an amount of 0.01 to 0.8% by weight based on the iron element, and the iron element dissolution rate of the magnetic iron oxide is up to 10% by weight. 62. The ratio (B _Cu / A _Cu ) × 100 of the content B _Cu of the content of iron to the content A _Cu of all Cu elements present in the magnetic iron oxide is 70 to 100%. Or 62
The process cartridge according to 1. 66. The magnetic iron oxide contains 0.1 to 0.6% by weight of Ni element based on iron element, and the Ni element exists when the iron element dissolution rate of the magnetic iron oxide is up to 20% by weight. 63. The ratio (B _Ni / A _Ni ) × 100 of the content B _Ni of the magnetic iron oxide to the content A _Ni of all Ni elements present in the magnetic iron oxide is 40 to 100%. 63. The process cartridge according to 62. 67. The process cartridge according to claim 61, wherein said magnetic iron oxide has a bulk density of 0.4 to 0.8 g / cm ³ . 68. The process cartridge according to claim 61, wherein the magnetic iron oxide has a sphericity of 0.80 or more. 69. The magnetic iron oxide having a number average particle size of 0.5.
7. The thickness of the film is from 0.05 to 1.00 μm.
69. The process cartridge according to any one of 1 to 68. 70. The magnetic iron oxide having a number average particle size of 0.1.
7. The structure according to claim 6, wherein the thickness is 10 to 0.40 μm.
69. The process cartridge according to any one of 1 to 68. 71. The magnetic toner having a volume average particle size of 2.
The process cartridge according to any one of claims 61 to 70, wherein the thickness is 5 to 6.0 µm. 72. The magnetic toner according to claim 61, wherein the magnetic iron oxide contains 20 to 200 parts by weight of the magnetic iron oxide based on 100 parts by weight of the binder resin. Process cartridge. 73. The magnetic toner according to claim 61, wherein the magnetic iron oxide contains 30 to 150 parts by weight of the magnetic iron oxide based on 100 parts by weight of the binder resin. Process cartridge. 74. The magnetic toner according to claim 61, wherein the magnetic toner particles further contain a hydrocarbon wax, an ethylene-based olefin polymer or an ethylene-based olefin copolymer as a fixing aid. The process cartridge according to any one of the above. 75. The magnetic toner particles may contain 1 to 30 mg.
The polypropylene wax having an acid value of KOH / g is further contained.
4. The process cartridge according to any one of 3. 76. The magnetic toner particles may contain 1 to 30 mg.
The polypropylene wax having an acid value of KOH / g is further contained.
4. The process cartridge according to any one of 3. 77. The process cartridge according to claim 75, wherein said wax contains 3% by weight or more of an ethylene component. 78. The wax contains an ethylene component of 3 to 2
The process cartridge according to claim 75, wherein the process cartridge contains 0% by weight. 79. The wax, wherein an ethylene component is 3-1.
The process cartridge according to claim 75, wherein the process cartridge contains 0% by weight. 80. The process cartridge according to claim 75, wherein said wax is modified with an acid monomer selected from at least one of maleic acid, maleic acid half ester, and maleic anhydride. 81. The process cartridge according to claim 61, wherein said magnetic toner has a mixture of said magnetic toner particles and inorganic fine powder. 82. The process cartridge according to claim 81, wherein said inorganic fine powder is subjected to a hydrophobic treatment. 83. The method according to claim 81, wherein the inorganic fine powder comprises silica fine powder or titanium fine powder.
3. The process cartridge according to 2. 84. The process cartridge according to claim 81, wherein said fine silica powder is treated with a silane coupling agent and silicone oil. 85. The silica fine powder is treated with a silane coupling agent and then treated with a silicone oil, or simultaneously treated with a silane coupling agent and a silicone oil. The process cartridge according to 1. 86. The magnetic toner, wherein the magnetic toner particles 1
The inorganic fine powder is added in an amount of 0.1 to 5.0 parts by weight to 00 parts by weight.
86. The device has a weight part.
The process cartridge according to any one of the above. 87. The process cartridge according to claim 81, wherein the magnetic toner has a mixture having resin fine particles in addition to the magnetic toner particles and the inorganic fine powder. 88. The process cartridge according to claim 61, wherein said electrostatic latent image holding member is a photoconductor for electrophotography. 89. The process cartridge according to claim 61, wherein said process cartridge further comprises a cleaning means for cleaning a surface of said electrostatic latent image holding member. . 90. The process cartridge has a toner carrier for carrying and transporting the magnetic toner, and the electrostatic latent image holding property and the toner carrier are spaced from each other. The process cartridge according to any one of claims 61 to 89, wherein the thickness of the toner layer provided by the magnetic toner carried on the surface of the toner carrier is smaller than the distance.