JP2002091093A - Magnetic material dispersion type resin carrier, two- component developer and method for forming image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic material dispersion type resin carrier excellent in durability and developing property. SOLUTION: In the magnetic material dispersion type resin carrier prepared by coating the surface of the carrier core having metal compound particles dispersed in a binder resin with silicone resin, the Si/Fe ratio of the carrier satisfies 0.003<=Si/Fe<=0.03. The reduction rate in the Si/Fe ratio after the carrier is cleaned with toluene satisfies 1.5% <= reduction rate in Si/Fe(%)<=15%. The transmittance for light when the carrier is dispersed in an aqueous solution satisfies transmittance T(%)>=95%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic material-dispersed resin carrier having excellent durability and stable chargeability, and further relates to a two-component developer and an image forming method.

[0002]

2. Description of the Related Art As an electrophotographic method, US Pat.
Various methods are described in JP-B-97,691, JP-B-42-23910 and JP-B-43-24748. In these methods, an electrostatic image is formed by irradiating a photoconductive layer with a light image corresponding to an original, and then toner is adhered on the electrostatic image to develop the electrostatic image, and if necessary, After transferring the toner image onto a transfer material such as paper, the toner image is fixed by heat, pressure, heat and pressure or solvent vapor to obtain a copy or print.

In recent years, with the development of computers and multimedia, there is a demand for means for outputting higher definition images such as small letters, photographs, and color originals in a wide range of fields from offices to homes. Heavy users demand high durability without deterioration in image quality even when copying or printing a large number of sheets, and in small offices and homes, obtain high-quality images, reduce the size of the device from the viewpoint of space saving and energy saving, and reduce waste toner. There is a demand for recycling, waste toner-less (cleaner-less), and lowering the fixing temperature, and various studies have been made from each viewpoint to achieve these objects.

In the electrophotographic method, the step of developing an electrostatic image is to form an image of the charged toner particles on the electrostatic image by utilizing the electrostatic interaction of the electrostatic image.
Of the developers for developing electrostatic images using toner, one-component developer using magnetic toner in which magnetic material is dispersed in resin, and two-component developer using non-magnetic toner mixed with magnetic carrier The latter is preferably used in a full-color image forming apparatus such as a full-color copying machine or a full-color printer, which requires a high image quality.

As a magnetic carrier used for a two-component developer, an iron powder carrier, a ferrite carrier, or a magnetic material-dispersed resin carrier in which magnetic fine particles are dispersed in a binder resin are known. In the iron powder carrier, since the carrier specific resistance is low, the charge of the electrostatic charge image leaks through the carrier and disturbs the electrostatic charge image, which may cause an image defect.

Even when a ferrite carrier having a relatively high specific resistance is used, in particular, in a developing method in which an alternating electric field is applied, charge leakage of an electrostatic image through the carrier may not be prevented in some cases. Since these have a large saturation magnetization, the magnetic brush becomes stiff, and the magnetic brush may appear on the toner image in some cases.

In order to solve such a problem, there has been proposed a magnetic material-dispersed resin carrier in which magnetic fine particles are dispersed in a binder resin. Compared with ferrite carriers, magnetic material-dispersed resin carriers have relatively high specific resistance, low saturation magnetization, and low true specific gravity, so the magnetic brush of the carrier does not become rigid, and good toner images without texture Can be formed.

Further, in the conventional two-component type developer, a part of the toner particles is deposited on the surface of the carrier particles by mechanical collision such as collision between particles and collision between particles and a developing machine, or heat generated by these. There is a property of so-called "spent formation" in which a film is physically attached to form a film. In such a situation, a film of the components of the toner is gradually accumulated on the surface of the carrier particles, and the frictional charge between the carrier particles and the toner particles is replaced with the frictional charge between the toners, so that the entire developer is charged. The triboelectric charging characteristics are deteriorated, and a large amount of toner adheres to the background portion of the copy image. This causes a so-called “ground stain” phenomenon. In contrast, the above-described magnetic substance dispersed resin carrier has a small saturation magnetization, Further, since the true specific gravity is small, it is advantageous for such spent, and further, the small true specific gravity has an advantage that the developing device can be lightened. Copy quality will be degraded. Further, when the formation of a film by the toner component on the carrier surface becomes remarkable, the entire developer must be replaced, which leads to an increase in cost.

On the other hand, the above-mentioned magnetic material-dispersed resin carrier has a small saturation magnetization and a small true specific gravity, which is advantageous for such spent. Has the advantage of being lighter.

[0010] Further, the magnetic material-dispersed resin carrier has excellent fluidity since it is relatively easy to form a spherical shape having small particle distortion and high particle strength. Since the size can be controlled in a wide range, it is expected to be applied to high-speed copying machines and high-speed laser beam printers.

However, the magnetic material-dispersed resin carrier has a problem that the magnetic material may be missing from the carrier particles, and the durability should be further improved. Further, the toner spent is still not enough.

Further, in the toner used for the two-component developer, inorganic fine particles are preferably added to the surface of the toner particles for the purpose of improving charging characteristics, fluidity and transferability. In the case of using a magnetic material-dispersed resin carrier in combination with a toner to which fine particles are externally added, the unevenness present on the particle surface of the magnetic material-dispersed resin carrier, and the protrusions scrape off the inorganic fine particles present on the toner surface, A so-called external additive adhesion phenomenon that the scraped fine particles adhere to the concave portions may occur. As a result, in addition to the deterioration of the charging performance that the carrier should give to the toner, the charging characteristics, fluidity, and transferability of the toner itself are impaired, causing image defects.

The external additive adhered to the concave portion on the particle surface of the magnetic material-dispersed carrier has the same behavior as the toner, and is formed in the developing area by an AC bias voltage applied to the developing sleeve which is a developer carrier. Is developed on the photoreceptor by the alternating electric field, and then further transferred onto the recording material.
The toner is fixed by the fixing device, but a part of the toner remains on the photosensitive member without being transferred, and is collected by the cleaning member. Therefore, the inorganic fine particles more than necessary are supplied to the fixing device and the cleaning device, so that the life of the fixing device and the life of the photosensitive member are shortened, which may greatly affect the image forming apparatus main body.

In order to solve these problems, a method of coating the surface of a magnetic material-dispersed resin carrier with a resin can be preferably used. Further, since the charging characteristics of the toner can be easily controlled by the charging characteristics of the resin to be coated, a desired charge can be imparted to the toner by selecting the resin to be coated.

However, as described above, a carrier which is effective in spent resistance and impact resistance and has stable charging characteristics for a long time has not yet been obtained.

[0016] Further, the magnetic substance-dispersed resin carrier tends to have a higher resistance than the ferrite carrier, and if the resin is coated to solve the above problem, the resistance is further increased. become. When an image is formed under a low-temperature and low-humidity environment using such a carrier, an image with an edge is obtained. On the other hand, a problem that an image density in a central portion is extremely low on an image surface having a large area, May occur. In some cases, the contrast required for obtaining a sufficient image density must be increased. Density fluctuation due to durability may increase.

[0017]

As described above, in consideration of the above-mentioned required characteristics of the carrier, the conventional carrier still has a problem to be improved, and further improvement is desired.

In particular, in a magnetic material-dispersed resin carrier in which magnetic particles are dispersed in a binder resin, the durability, developability, the spent resistance including the attachment of external additives, and the charge imparting property to the toner are as follows. There is a need for improved carriers.

An object of the present invention is to propose a magnetic carrier which solves the above problems, a two-component developer having the magnetic substance-dispersed carrier and a toner, and an image forming method using the two-component developer. It is in.

An object of the present invention is to propose a magnetic carrier having excellent durability, a two-component developer having the magnetic material-dispersed carrier and a toner, and an image forming method using the two-component developer. It is in.

An object of the present invention is to propose a magnetic carrier having excellent developability, a two-component developer having the magnetic material-dispersed carrier and a toner, and an image forming method using the two-component developer. It is in.

An object of the present invention is to provide a magnetic carrier having excellent spent resistance including an external additive adhered thereto, a two-component developer having the magnetic material-dispersed carrier and a toner, and the use of the two-component developer. The purpose of the present invention is to propose an image forming method.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a magnetic carrier having an excellent charge imparting property to a toner, a two-component developer having the magnetic material-dispersed carrier and a toner, and an image forming method using the two-component developer. The idea is to propose a method.

[0024]

The above objects can be achieved by the following constitutions of the present invention.

The present invention relates to a magnetic material-dispersed resin carrier in which the surface of a carrier core in which metal compound particles are dispersed in a binder resin is coated with a silicone resin, wherein the Si / Fe ratio of the carrier is 0.003 ≦ Si /Fe≦0.03, and the Si /
The Fe ratio reduction ratio satisfies 0.5% ≦ Si / Fe reduction ratio (%) ≦ 15%, and the light transmittance when the carrier is dispersed in an aqueous solution is such that the transmittance T (%) ≧ 80% And a magnetic material-dispersed resin carrier characterized by satisfying the following conditions.

The present invention also provides a magnetic material-dispersed resin carrier in which the surface of a carrier core in which metal compound particles are dispersed in a binder resin is coated with a silicone resin, and a toner containing at least a binder resin and a colorant. And the carrier has an Si / Fe ratio satisfying 0.003 ≦ Si / Fe ≦ 0.03, and the carrier has a Si / Fe ratio after washing with toluene.
The Fe ratio reduction ratio satisfies 0.5% ≦ Si / Fe reduction ratio (%) ≦ 15%, and the light transmittance when the carrier is dispersed in an aqueous solution is such that the transmittance T (%) ≧ 80% And the toner comprises at least a polyester resin as the binder resin.

Further, according to the present invention, the electrostatic image carrier is charged by a charging means, the charged electrostatic image carrier is exposed to form an electrostatic image on the electrostatic image carrier, and the electrostatic image is formed. A toner image is formed on an electrostatic image carrier by developing with a developing means having a two-component developer, and the toner image on the electrostatic image carrier is transferred via an intermediate transfer member or without an intermediate transfer member. In a method of forming an image by transferring the toner image on a transfer material and fixing the toner image on the transfer material by a heat and pressure fixing unit, the two-component developer has at least a toner and a magnetic material-dispersed resin carrier. Contains at least a binder resin for toner and a colorant, and contains at least a polyester resin, and the magnetic substance-dispersed resin carrier has metal compound particles dispersed in the binder resin. Careerco Surface is a magnetic material-dispersed resin carrier coated with a silicone resin, of the carrier Si / F
e ratio satisfies 0.003 ≦ Si / Fe ≦ 0.03, and Si /
The Fe ratio reduction ratio satisfies 0.5% ≦ Si / Fe reduction ratio (%) ≦ 15%, and the light transmittance when the carrier is dispersed in an aqueous solution is such that the transmittance T (%) ≧ 80% And an image forming method characterized by satisfying the following.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION As a result of intensive studies by the present inventors,
In a magnetic material-dispersed resin carrier in which the surface of a carrier core in which metal compound particles are dispersed in a binder resin is coated with a silicone resin, the Si / Fe ratio of the carrier is 0.003 ≦ Si / Fe ≦ 0.03. And the Si /
The Fe ratio reduction ratio satisfies 0.5% ≦ Si / Fe reduction ratio (%) ≦ 15%, and the light transmittance when the carrier is dispersed in an aqueous solution is such that the transmittance T (%) ≧ 80% It has been found that by satisfying the above condition, good image quality can be obtained over a long period of time.

The details will be described below.

When the surface of the carrier core in which the metal compound particles are dispersed in the binder resin is coated with a silicone resin, the surface energy of the resin is advantageous for the spent resistance of the toner and the external additive. In addition, the silicone resin is excellent in adhesion to the base material, resistant to coating peeling, and can provide a carrier excellent in charge imparting performance to toner.

In addition, a stable image can be obtained even with long-term durability without peeling of the magnetic substance and the resistance adjusting agent, which is a disadvantage peculiar to the magnetic substance-dispersed carrier.

At this time, when the Si / Fe ratio of the carrier coated with the silicone resin is less than 0.003, sufficient effects on the above-mentioned spent resistance, charge imparting property, and peeling of the magnetic material are obtained. Can not be. Further, the core of the magnetic substance dispersed type carrier has more irregularities on the surface than the ferrite carrier, and has a porous shape. Therefore, when the Si / Fe ratio is less than 0.003, the resin penetrates into the holes existing inside the core, and the amount of the resin actually present on the surface varies depending on the lot, so that the production stability is unstable. May remain.

If the Si / Fe ratio exceeds 0.03, the resistance is further increased, and particularly in a low humidity environment, the edge of the image is excessively emphasized, and the latitude for the transfer and the fixing device configuration is reduced. I will. In addition, there is a problem that the image density in the central portion becomes extremely low on a large-area image surface. Further, although the reason is not clear, the charge distribution becomes broad due to the increase in the coat thickness, and in some cases, the contrast required to obtain a sufficient image density must be increased. Furthermore, the broadening of the charge distribution causes so-called selective development, in which only particles having an appropriate charge for development are developed, and toner particles having an inappropriate charge are left in a developing device. In some cases, the concentration may be reduced.

When the Si / Fe reduction rate (%) of the magnetic material-dispersed resin carrier coated with the silicone resin, which is reduced by washing with toluene, is less than 0.5%, the coating is peeled off and the magnetic material is removed. Easily detached, resulting in poorly durable carriers. Si / F
e Reduction rate (%) is considered to indicate the amount of the low molecular weight component of the silicone resin, and if less than 0.5%, the film strength of the resin becomes too hard, the flexibility is poor, and the We believe that the film is inferior in adhesion.

Further, the Si / Fe reduction rate (%) is 15%.
If the ratio exceeds the above range, the carrier may be poor in fluidity of the carrier, adhesion of the external additive, toner spent property, and miscibility with the toner. This is thought to be caused by the presence of more low molecular weight components than necessary.

The magnetic substance-dispersed resin carrier coated with the silicone resin is shaken for 5 minutes, then dispersed in an aqueous solution in which a surfactant is dropped, and the light transmittance T (%) when left standing for 5 minutes is obtained. If less than 80%, the carrier will have poor durability. This is the light transmittance T
(%) Is considered to indicate the easiness of peeling of the magnetic substance and the resistance adjuster dispersed in the binder resin, and when less than 80%, the coating amount represented by Si / Fe alone We believe that the weakness of the core itself, which cannot be covered completely, may be the cause. Also, the carrier in such a state,
Image defects such as a magnetic substance and a resistance adjuster attached to the initial image were also observed. Furthermore, using such a core having a low strength may cause a lot of variation in the charge amount depending on the lot, so that there is a concern that production stability may remain uneasy.

In the present invention, the measurement of the Si / Fe ratio was performed by the following measuring method.

<Method of Measuring Si / Fe Ratio> Carrier and Si
And a toner containing no Fe component at a toner concentration of 8%, shaken, packed in a ring having a diameter of 20 mm, and pressed into a sample press molding machine (BR-E31: MAEKA).
Pressing with a WA Testing Machine Co., Ltd.) and X-ray fluorescence (RIX-3000: Rigaku Denki Kogyo Co., Ltd.)
Manufactured), the Si strength and the Fe strength were measured. Si / F
The e ratio was determined by dividing the measured intensity of Si by the measured intensity of Fe.

In the present invention, the following methods were used for the toluene washing and the Si / Fe ratio reduction rate after the washing.

<Method of Measuring Si / Fe Ratio Reduction Ratio> 40 cc of toluene was added to 20 g of the carrier, and the carrier was shaken about 200 times to be well-adapted. Then, the mixture was left for 60 minutes, suction-filtered with a Kiriyama funnel, and only the carrier was taken out. Further drying was performed at 80 ° C. for 12 hours to obtain a toluene-washed carrier. The measurement of the Si / Fe ratio was performed in the same manner as the above method, and the reduction rate was calculated by the following equation.

Si / Fe ratio reduction rate = (Si / Fe ratio <before cleaning> −Si / Fe ratio <after cleaning>) / (Si / Fe ratio <before cleaning>) × 100

In the present invention, the transmittance T (%) was determined by the following method.

<Method of Measuring Transmittance T (%)> Carrier 50
g was shaken at 125 times / min for 5 minutes. Add 10% surfactant and 10 ml of water to 1 g of shaken carrier,
He shakes his hand 200 more times. Thereafter, the mixture was allowed to stand for 5 minutes, and the supernatant was subjected to light transmittance T at 600 nm using a UV autographing spectrophotometer UV-2200 (manufactured by Shimadzu Corporation).
(%) Was measured.

The specific resistance of the carrier is 1 × 10 ⁸ to 1 × 1.
0 ¹⁵ Ω · cm, more preferably
It is preferably 1 × 10 ⁹ to 1 × 10 ¹⁴ Ω · cm.

When the specific resistance of the carrier is less than 1 × 10 ⁸ Ω · cm, the carrier is liable to adhere to the surface of the photoreceptor, causing damage to the photoreceptor or being directly transferred onto paper to cause image defects. Easily occur. Further, the developing bias may leak through the carrier and disturb the electrostatic latent image drawn on the photosensitive drum.

If the specific resistance of the carrier exceeds 1 × 10 ¹⁵ Ω · cm, a sharp edge-enhanced image is easily formed, and the charge on the carrier surface is hardly leaked.
In some cases, the image density may decrease due to the charge-up phenomenon, and fogging and scattering may occur due to the inability to apply the charge to the newly replenished toner.
Further, the toner may be charged with a substance such as the inner wall of the developing device, and the charge amount of the toner which should be applied may become non-uniform. In addition, image defects such as electrostatic adhesion of external additives are likely to occur.

The specific resistance of the carrier was measured using a powder insulation resistance measuring instrument manufactured by Vacuum Riko Co., Ltd.
Measurement conditions, 23 ° C., put left carrier for 24 hours or more 60% under the conditions in the measuring cell diameter ^{20mm (0.283cm 2), 11.8kPa (} 120g / cm 2)
, A thickness of 2 mm, and an applied voltage of 50 mm.
It was measured at 0V.

The magnetic properties of the carrier are 1000 / 4π
(KA / m) is preferably 20 to 10
0 (Am ² / kg), more preferably 30 to 65 (Am ² / kg)
/ Kg).

The carrier has a magnetization intensity of 100 (Am ² /
kg), the density of the magnetic brush formed on the developing sleeve at the developing pole decreases, the spike length becomes longer, and it becomes rigid. Eye irregularities are likely to occur, and particularly, the durability of the developer is likely to deteriorate due to copying or printing a large number of sheets.

The carrier has a magnetization intensity of 20 (Am ² / k
If the value is less than g), the magnetic force of the carrier is reduced even if the carrier fine powder is removed, the carrier is likely to adhere, and the toner transportability is likely to be reduced.

The measurement of the magnetic properties of the carrier was performed by using an oscillating magnetic field type automatic magnetic property recording apparatus BHV-3 manufactured by Riken Denshi Co., Ltd.
5 was performed. As the measurement conditions, an external magnetic field of 1000 / 4π (kA / m) was created for the magnetic characteristics of the carrier powder, and the magnetization intensity at that time was determined. The carrier is packed in a cylindrical plastic container so that the carrier particles are sufficiently dense so that the carrier particles do not move, the magnetization moment is measured in this state, and the actual weight when the sample is placed is measured. And the intensity of magnetization (Am ² / kg).

The carrier has a volume average particle size of 15 to 60 μm.
m is preferable, and more preferably 25 to 50 μm. When the carrier volume average particle diameter is less than 15 μm, it may not be possible to sufficiently prevent the carrier from adhering to the non-image area due to particles on the fine particle side of the carrier particle size distribution. When the volume average particle diameter of the carrier is larger than 60 μm, the texture due to the rigidity of the magnetic brush does not occur,
In some cases, unevenness of the image due to the size may occur.

According to the particle size distribution of the carrier of the present invention, the content of particles having a particle size of ／ or less of the volume average particle size is 5% by volume.
The following is preferred. If it exceeds 2/3,
Carrier adhesion due to carrier fines tends to occur. The average particle size was indicated by a value measured by a laser diffraction type particle size distribution meter (manufactured by Horiba, Ltd.).

In the present invention, examples of the metal compound particles used for the carrier core include magnetite or ferrite having magnetism represented by the following formula (1) or (2).

MO.Fe ₂ O ₃ ... (1) M.Fe ₂ O ₄ ... (2) (where M represents a trivalent, divalent or monovalent metal ion)

As M, Mg, Al, Si, Ca, S
c, Ti, V, Cr, Mn, Fe, Co, Ni, Cu,
Zn, Sr, Y, Zr, Nb, Mo, Cd, Sn, B
a, Pb, and Li, which can be used alone or in combination.

Specific examples of the magnetic compound particles having magnetism include, for example, magnetite, Zn-Fe
Ferrite, Mn-Zn-Fe ferrite, Ni-Z
n-Fe ferrite, Mn-Mg-Fe ferrite, C
Examples include iron-based oxides such as a-Mn-Fe-based ferrite, Ca-Mg-Fe-based ferrite, Li-Fe-based ferrite, and Cu-Zn-Fe-based ferrite.

Further, in the present invention, as the metal compound particles used for the carrier core, a mixture of the above-described magnetic metal compound and the following non-magnetic metal compound may be used.

As the non-magnetic metal compound, for example, A
l ₂ O ₃ , SiO ₂ , CaO, TiO ₂ , V ₂ O ₅ , CrO,
MnO ₂ , α-Fe ₂ O ₃ , CoO, NiO, CuO, Zn
O, SrO, Y ₂ O ₃ and ZrO ₂ are mentioned. In this case, one kind of metal compound can be used, but it is particularly preferable to use a mixture of at least two or more kinds of metal compounds. In that case, it is more preferable to use particles having similar specific gravities and shapes in order to increase the adhesion to the binder resin and the strength of the carrier core particles.

Specific examples of the combination include, for example, magnetite and hematite, magnetite and γ-Fe
₂ O ₃ , magnetite and SiO ₂ , magnetite and Al ₂ O
₃ , magnetite and TiO ₂ , magnetite and Ca-Mn-
Fe-based ferrite, magnetite and Ca-MgFe-based ferrite can be preferably used. Among them, a combination of magnetite and hematite can be particularly preferably used.

When the above-mentioned magnetic metal compound is used alone or in combination with a non-magnetic metal compound, the number average particle diameter of the magnetic metal compound is determined by the number average particle diameter of the carrier core. It is preferably 0.02 to 2 μm, and more preferably 0.05 to 1 μm.

When the number average particle diameter of the metal compound exhibiting magnetism is less than 0.02 μm, it becomes difficult to obtain preferable magnetic properties. If the number average particle diameter of the magnetic metal compound exceeds 2 μm, it is difficult to obtain a carrier having a high strength and a preferable particle diameter due to uneven granulation.

When a mixture of a magnetic metal compound and a nonmagnetic compound is used, the number average particle size of the nonmagnetic metal compound is preferably 0.05 to 5 μm, more preferably 0.1 to 3 μm. Good to be. In this case, the number average particle diameter (average particle diameter ra) of the metal compound having magnetism,
The particle size ratio (rb / ra) to the number average particle size (average particle size rb) of the nonmagnetic metal compound is preferably 1.0 to 3.0.
0, more preferably 1.2 to 3.0.

The number average particle diameter of the non-magnetic metal compound is 0.1.
When the thickness is less than 05 μm, favorable resistance cannot be obtained, and the carrier tends to adhere. When the number average particle size of the nonmagnetic metal compound exceeds 5 μm, it is difficult to obtain a carrier having a preferable particle size with high strength due to non-uniform granulation.

Further, when rb / ra is less than 1.0, ferromagnetic metal compound particles having a low specific resistance tend to emerge on the surface, it is difficult to increase the specific resistance of the carrier core, and the effect of preventing carrier adhesion is obtained. It is difficult to obtain. When rb / ra exceeds 5, the strength of the carrier tends to decrease, and the carrier is likely to be destroyed.

The number average particle diameter of the metal oxide was measured by a transmission electron microscope H-800 manufactured by Hitachi, Ltd.
Using a photographic image magnified 00 to 20000 times, 300 or more particles having a particle size of 0.01 μm or more were randomly extracted, and an image processing analysis device Luzex3 manufactured by Nireco Co., Ltd. was used.
Was measured as the metal oxide particle size with the Feret diameter in the horizontal direction, and averaged to calculate the number average particle size.

The specific resistance of the metal compound dispersed in the binder resin is such that the specific resistance of the magnetic metal compound particles is 1 × 1.
It is preferably in the range of 0 ³ Ω · cm or more. In particular, when a magnetic metal compound and a nonmagnetic compound are used in combination, the specific resistance of the magnetic metal compound particles is 1
× 10 ³ Ω · cm or more is preferable, and the other nonmagnetic metal compound particles preferably have higher specific resistance than the magnetic metal compound particles, and are preferably used.
The specific resistance of the nonmagnetic metal compound used in the present invention is 1 × 10
^It is preferably ⁸ Ω · cm or more, more preferably 1 × 10 ¹⁰ Ω · cm or more.

The specific resistance of the magnetic metal compound particles is 1
When the content is less than × 10 ³ Ω · cm, it is difficult to obtain a desired high specific resistance even if the content is reduced, which leads to charge injection, image quality deterioration and carrier adhesion. When a mixture of a magnetic metal compound and a nonmagnetic compound is used, the specific resistance of the nonmagnetic metal compound is 1 × 10 ⁸ Ω · cm.
If it is less than the specific resistance of the magnetic carrier core becomes low,
After all, image quality deterioration such as carrier adhesion is likely to occur.

In the present invention, the specific resistance of the magnetic metal compound and the non-magnetic metal compound is measured according to the method of measuring the specific resistance of carrier particles.

In the carrier core of the present invention, the content of the metal compound is preferably 80 to 99% by mass based on the carrier core.

When the content of the metal compound is less than 80% by mass, the chargeability tends to be unstable, and the carrier is charged particularly in a low-temperature and low-humidity environment, and the residual charge tends to remain. And an external additive easily adhere to the surface of the carrier particles, and a proper specific gravity cannot be obtained. When the content of the metal compound exceeds 99% by mass, the strength of the carrier decreases, and problems such as cracking of the carrier due to durability tend to occur.

Further, in a preferred embodiment of the present invention, in the carrier core containing a mixture of a magnetic metal compound and a non-magnetic compound, the content of the magnetic metal compound in the whole metal compound is preferably The content is preferably 50 to 95% by mass, more preferably 55 to 95% by mass.

When the content of the metal compound having magnetism in the whole metal compound is less than 50% by mass, the resistance of the core is improved, but the magnetic force as a carrier is reduced, and the carrier adhesion is reduced. May be invited. If the content of the magnetic metal compound in the whole metal compound exceeds 95% by mass, depending on the specific resistance of the magnetic metal compound, it may not be possible to achieve a more desirable high core resistance.

In the present invention, the specific gravity of the carrier is 2.5
-4.5 is preferred. If it is lower than 2.5, it cannot be uniformly mixed when it is mixed with the toner as a developer.
On the other hand, if it is larger than 4.5, the damage to the toner is increased, which is not only disadvantageous to the toner deterioration but also the weight of the developing unit is heavy, so that the characteristics of the resin carrier cannot be fully utilized. .

The binder resin of the carrier core particles used in the present invention is a thermosetting resin, and a part or all of the binder resin is 3%.
It is preferable that the resin is a cross-linked resin. Thereby, the dispersed metal compound particles can be firmly bound, so that the strength of the carrier core can be increased, and the detachment of the metal compound hardly occurs even in a large number of copies,
Further, the silicone resin as the coating resin can be coated better, and as a result, high image quality can be maintained.

The method for obtaining the magnetic material-dispersed carrier core is not particularly limited to the method described below, but in the present invention, a solution in which the monomer and the solvent are uniformly dispersed or dissolved is used. From the inside, the production method of the polymerization method of generating particles by polymerizing the monomer, particularly, by subjecting the metal oxide dispersed in the carrier core particles to lipophilic treatment, a sharp particle size distribution, fine powder A method for obtaining a small magnetic substance dispersed resin carrier core is as follows.
It is preferably used.

To achieve high image quality, it is preferable to use in combination with a small particle size toner having a weight average particle size of 1 to 10 μm, but the carrier particle size is also reduced according to the particle size of the toner. The above-mentioned production method is particularly preferable because even if the carrier particle size is reduced, a carrier with a small amount of fine powder can be produced regardless of the average particle size.

The monomers used for the binder resin include:
Radical polymerizable monomers can be used. For example, styrene; o-methylstyrene, m-methylstyrene, p-methoxystyrene, p-ethylstyrene, p-methylstyrene
Styrene derivatives such as tertiary butyl styrene; acrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate, n-propyl acrylate, isobutyl acrylate, octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, Acrylic esters such as stearyl acrylate, 2-chloroethyl acrylate, and phenyl acrylate; methacrylic acid, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-methacrylate Octyl, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminomethyl methacrylate, diethylaminoethyl methacrylate,
Methacrylates such as benzyl methacrylate;
2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate; acrylonitrile, methacrylonitrile, acrylamide; methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, n-butyl ether, isobutyl ether, β-chloroethyl vinyl ether, phenyl vinyl ether, p-methylphenyl ether And vinyl ethers such as p-chlorophenyl ether, p-bromophenyl ether, p-nitrophenyl vinyl ether and p-methoxyphenyl vinyl ether; and diene compounds such as butadiene.

These monomers can be used alone or as a mixture, and a suitable polymer composition capable of obtaining preferable characteristics can be selected.

As described above, the binder resin of the carrier core particles is preferably three-dimensionally cross-linked. However, as a cross-linking agent for three-dimensionally cross-linking the binder resin,
It is preferable to use a crosslinking agent having two or more polymerizable double bonds per molecule. Examples of such a crosslinking agent include aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; ethylene glycol diacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, and 1,3-butylene glycol. Dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, 1,4-butanediol diacrylate, neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, penta Erythritol dimethacrylate, pentaerythritol tetramethacrylate, glycerol Alkoxy dimethacrylate, N, N-divinyl aniline, divinyl ether, and a divinyl sulfide and divinyl sulfone. These may be used by mixing two or more kinds as appropriate. The cross-linking agent can be previously mixed with the polymerizable mixture, or can be added as needed during the polymerization.

Other monomers for the binder resin of the carrier core particles include bisphenols and epichlorohydrin as starting materials for the epoxy resin; phenols and aldehydes of the phenolic resin; ureas and aldehydes of the urea resin; melamine and aldehydes. No.

The most preferred binder resin is a phenolic resin. The starting materials are phenol, m
-Phenol compounds such as cresol, 3,5-xylenol, p-alkylphenol, resorcil, p-tert-butylphenol, and aldehyde compounds such as formalin, paraformaldehyde and furfural. Particularly, a combination of phenol and formalin is preferred.

When these phenol resins or melamine resins are used, it is preferable to use a basic catalyst as a curing catalyst. As the basic catalyst, various catalysts used in the production of ordinary resol resins can be used. Specific examples include amines such as aqueous ammonia, hexamethylenetetramine, diethyltriamine, and polyethyleneimine, and the use of aqueous ammonia is particularly preferred.

The carrier core particles may be subjected to a heat treatment as needed to further cure the resin. It is particularly preferable to carry out the reaction under reduced pressure or in an inert atmosphere in order to prevent oxidation of the inorganic compound fine particles and the like.

The temperature at that time is preferably lower, particularly preferably 100 ° C. or more and less than 180 ° C. The reason is not clear, but by treating at lower temperature, the unreacted monomer does not escape as a gas, effectively acting as a binder resin, and at the same time preventing the core from becoming porous, We think that it may be possible to coat evenly.

In the present invention, the metal compound contained in the carrier core is subjected to lipophilic treatment to sharpen the particle size distribution of the magnetic carrier particles and to prevent the metal compound particles from detaching from the carrier. Preferred above.
In the case of forming carrier core particles in which a lipophilic metal compound is dispersed, particles insoluble in a solution are generated at the same time as the polymerization reaction proceeds from a liquid in which a monomer and a solvent are uniformly dispersed or dissolved. At that time, it is considered that the metal oxide has an effect of uniformly and densely taking in the inside of the particles and an effect of preventing aggregation of the particles and sharpening the particle size distribution. Furthermore, when a metal compound subjected to lipophilic treatment is used, there is no need to use a suspension stabilizer such as calcium fluoride, and the suspension stabilizer remains on the carrier surface, thereby impairing the chargeability. It is possible to prevent the nonuniformity of the coating resin and the inhibition of the reaction when coating with a reactive resin such as a silicone resin.

In the lipophilic treatment, an organic compound having one or more functional groups selected from an epoxy group, an amino group and a mercapto group, or a lipophilic treatment agent which is a mixture thereof is used. Is preferred. In particular, an epoxy group is preferably used in order to obtain a carrier having a stable charging ability.

The magnetic metal oxide particles are preferably treated with 0.1 to 10 parts by weight, more preferably 0.2 to 6 parts by weight, per 100 parts by weight of the magnetic metal oxide particles. Is preferred in order to increase the lipophilicity and hydrophobicity of the magnetic metal oxide particles.

As the lipophilic treating agent having an epoxy group, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, β-
(3,4-epoxycyclohexyl) trimethoxysilane, epichlorohydrin, glycidol and styrene-
Glycidyl (meth) acrylate copolymer is exemplified.

Examples of the lipophilic treatment agent having an amino group include γ-aminopropyltrimethoxysilane, γ-aminopropylmethoxydiethoxysilane, γ-aminopropyltriethoxysilane, and N-β (aminoethyl)- γ-
Aminopropyltrimethoxysilane, N-β (aminoethyl) -γ-aminopropylmethyldimethoxysilane, N
-Phenyl-γ-aminopropyltrimethoxysilane, ethylenediamine, ethylenetriamine, styrene-dimethylaminoethyl (meth) acrylate copolymer, isopropyl tri (N-aminoethyl) titanate and the like are used.

As the lipophilic treatment agent having a mercapto group, for example, mercaptoethanol, mercaptopropionic acid and γ-mercaptopropyltrimethoxysilane are used.

The silicone resin can be used alone, but is preferably used in combination with a coupling agent in order to increase the strength of the coating layer and control the charging to a preferable level.
Further, the above-mentioned coupling agent is preferably used as a so-called primer agent, a part of which is treated on the carrier core surface before coating the resin, and the subsequent coating layer has a covalent bond. , Can be formed with higher adhesion.

As the coupling agent, aminosilane is preferably used. As a result, a positively chargeable amino group can be introduced into the carrier surface, and the toner can be favorably imparted with negative charge characteristics.

The coating of the resin may be performed by a known method, for example, a method of dry-mixing the composite particles and the resin using a Henschel mixer or a high-speed mixer, or a method of mixing the composite particles in a solvent containing the resin. How to impregnate,
Any method such as spraying a resin onto the composite particles using a spray drier may be used. In particular, a method of diluting the resin with a solvent such as toluene and coating with stirring in a Nauta mixer is preferably used.

During the coating treatment of the coating layer, in particular, at 30 ° C. to 80
At a temperature of 100 ° C., the coating treatment is performed at normal pressure, and the subsequent solvent removal is performed at 13300 to 79800 Pa (100 to 600 T).
It is preferably carried out under reduced pressure of (or).

Although the reason is not clear, the silicone resin is treated at normal pressure and adapted to the core particles, so that the resin penetrates firmly into the core. I believe that can be made. In addition, by performing the subsequent solvent removal under reduced pressure, the time required for solvent removal is reduced, the share on the carrier surface is minimized, and the carrier can be obtained at least in the production stage without causing coating peeling. I believe. Furthermore, by a series of these steps, in the subsequent baking step, low-temperature treatment at least at 160 ° C. or less is possible, preventing excessive crosslinking of the resin,
The durability of the coating layer can be increased. Furthermore, it is considered that the Si / Fe reduction rate of the silicone resin carrier after washing with toluene can be easily controlled within the scope of the present invention.

The toner for constituting the two-component developer in combination with the carrier of the present invention contains at least a binder resin for toner and a colorant, and at least a polyester resin as the binder resin for the toner. It is particularly effective when it contains. That is, the polyester resin is excellent in fixing property and color mixing property, and is particularly preferably used as a binder resin for a color toner. However, on the other hand, the polyester resin has a strong negative charging ability, and has a problem that the charging tends to be excessive particularly in a low humidity environment. I was However, when used in combination with the carrier of the present invention, it is possible to suppress excessive charging of the toner and obtain excellent developability.

Other binder resins for toner include polystyrene; high molecular compounds obtained from styrene derivatives such as poly-p-chlorostyrene and polyvinyltoluene; styrene-p-chlorostyrene copolymer and styrene-vinyltoluene copolymer. Polymer, styrene-vinylnaphthalene copolymer, styrene-acrylate copolymer, styrene-
Methacrylic acid ester copolymer, styrene-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ketone copolymer,
Styrene copolymers such as styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer; polyvinyl chloride, phenolic resin, modified phenolic resin, maleic resin, acrylic resin, methacrylic resin, poly Vinyl acetate, silicone resin; polyester resin having as a structural unit a monomer selected from aliphatic polyhydric alcohol, aliphatic dicarboxylic acid, aromatic dicarboxylic acid, aromatic dialcohols and diphenols; polyurethane resin, polyamide Resins, polyvinyl butyral, terpene resins, cumarone indene resins, and petroleum resins.

Further, the toner has a shape factor SF-1 of 10
More preferably, it is 0 to 120.

In a toner having a shape factor SF-1 of more than 120, the change in the fluidity of the developer tends to be large.
In a long-term durability test, the charge amount easily changes. S
The toner having an F-1 in the range of 100 to 120 has a high transfer efficiency on paper, and can provide the same density as the conventional toner even if the amount of toner put on the photoreceptor is small.
It is also advantageous in terms of cost. In addition, since the toner easily rolls on the carrier and the packing density of the developer tends to be high, there are many chances of contact with the carrier, and it is easy to always maintain stable charge.

The shape factor SF-1 of the toner was measured using a FE-SEM (S-800) manufactured by Hitachi, Ltd.
300) are randomly sampled, and the image information is introduced into an image analysis device (Luzex3) manufactured by Nireco via an interface, analyzed, and the value calculated by the following equation is used as the toner value. Is defined as the shape factor SF-1.

[0102]

(Equation 1) (Where MXLNG indicates the maximum diameter of the toner, and AREA
Indicates the projected area of the toner. )

A toner having a core / shell structure and having a core formed of a material having a low softening point is also preferably used. Although the above toner uses a low softening point substance, it is advantageous for low-temperature fixing.However, it tends to be disadvantageous to heat generation due to mechanical shear, and toner spent may occur in a developing device. The use of the carrier of the invention eliminates that concern.

As a method for encapsulating the low softening point substance in the toner particles, the polarity of the material in the aqueous medium is set to be smaller for the low softening point substance than for the main monomer, and a small amount of the larger polarity is used. By adding a resin or a monomer, toner particles having a so-called core / shell structure in which a low softening point substance is coated with an outer shell resin can be obtained.

The particle size distribution and the particle size of the toner can be controlled by changing the type and amount of the hardly water-soluble inorganic salt or dispersant to be used as a protective colloid, or by using mechanical device conditions such as a roller. A predetermined toner can be obtained by controlling the peripheral speed, the number of passes, stirring conditions such as the shape of the stirring blade, the shape of the container, or the solid concentration in the aqueous medium.

As the outer shell resin of the toner, styrene-
(Meth) acrylic copolymers, polyester resins, epoxy resins, styrene-butadiene copolymers may be mentioned.

In the method of directly obtaining toner particles by a polymerization method, those monomers are preferably used. Specifically, styrene; styrene monomers such as o (m-, p-)-methylstyrene and m (p-)-ethylstyrene; methyl (meth) acrylate, ethyl (meth) acrylate, (meth) ) Propyl acrylate, butyl (meth) acrylate, octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, behenyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, ( (Meth) acrylate monomers such as dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate; butadiene, isoprene, cyclohexene, (meth) acrylonitrile,
An ene monomer such as acrylamide is preferably used.

In these toners, it is preferable to use at least silica fine particles and / or titanium oxide fine particles as an external additive, since the fluidity can be favorably imparted to the developer and the life of the developer is improved. Further, by using these fine powders, a developer having less environmental fluctuation can be obtained.

Other external additives include metal oxide fine powder (aluminum oxide, strontium titanate, cerium oxide, magnesium oxide, chromium oxide, tin oxide, zinc oxide, etc.) and nitride fine powder (silicon nitride, etc.) , Carbide fine powder (silicon carbide, etc.), metal salt fine powder (calcium sulfate, barium sulfate, calcium carbonate, etc.), fatty acid metal salt fine powder (zinc stearate, calcium stearate, etc.), carbon black, resin fine powder (polytetra Fluoroethylene, polyvinylidene fluoride, polymethyl methacrylate, polystyrene, silicone resin, etc.) are preferred. Even if these external additives are used alone,
Also, a plurality of them may be used in combination. It is more preferable that the above-mentioned external additives including the silica fine powder have been subjected to a hydrophobic treatment.

The above-mentioned external additive has a number average particle size of 0.2.
It is preferably not more than μm. Number average particle size is 0.2
If it exceeds μm, the fluidity will decrease and the image quality will deteriorate during development and transfer.

The external additive is preferably used in an amount of preferably 0.01 to 10 parts by mass, more preferably 0.05 to 5 parts by mass, based on 100 parts by mass of the toner particles.

[0112] the external additive has a specific surface area by nitrogen adsorption according to the BET method is preferably 30 m ² / g or more, more preferably is suitable in the range of 50 to 400 m ² / g.

The mixing treatment of the toner particles and the external additive can be performed using a mixer such as a Henschel mixer.

In the present invention, examples of the colorant used in the toner include the following.

Examples of yellow colorants include condensed azo compounds, isoindolinone compounds, anthraquinone compounds,
Compounds represented by azo metal complexes, methine compounds and allylamide compounds are used. Specifically, C.I. I. Pigment Yellow 12, 13, 14, 15, 17, 6
2, 74, 83, 93, 94, 95, 109, 110,
111, 128, 129, 147, and 168 can be suitably used.

Examples of the magenta colorant include condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds and perylene compounds. Specifically, C.I.
I. Pigment Red 2, 3, 5, 6, 7, 23, 4
8: 2, 48: 3, 48: 4, 57: 1, 81: 1, 1
44, 146, 166, 169, 177, 184, 18
5, 202, 206, 220, 221, 254 can be suitably used.

Examples of the cyan coloring agent include copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, and basic dye lake compounds. Specifically, C.I. I. Pigment Blue 1, 7, 15, 15: 1, 15: 2, 1
5: 3, 15: 4, 60, 62, 66 can be suitably used.

These colorants can be used alone or as a mixture or in the form of a solid solution.

Examples of the black coloring agent include carbon black and the above-described yellow / magenta / cyan coloring agents which are toned to black.

In the case of a color toner, the hue angle,
The selection is made in consideration of saturation, lightness, weather resistance, OHP transparency, and dispersibility in toner. The content of the colorant is preferably 1 to 20 parts by mass based on 100 parts by mass of the binder resin for toner.

As the charge control agent used in the toner,
Known ones can be used. In the case of a color toner, a charge control agent which is colorless or light-colored and has a high toner charging speed and can stably maintain a constant charge amount is particularly preferable. Further, in the present invention, when a toner is produced by a polymerization method, a charge control agent having no polymerization inhibition and having no soluble matter in an aqueous medium is particularly preferable.

Further, the toner used in the present developer was 280 to 35 when the extract was extracted with 0.1 mol / l of sodium hydroxide and the absorbance was measured.
It is preferable to have at least one peak in the range of 0 nm. This peak is a peak derived from oxycarboxylic acid which is preferably used in the toner for the purpose of controlling charging, accelerating the curing of the binder resin and increasing the fluidity, and the like. Such an oxycarboxylic acid can impart high chargeability to the toner. However, depending on the binder resin, other materials, and the method of manufacturing the toner, an extremely low charge amount under high humidity or a charge-up of the toner under low humidity may be observed. Was.

However, by using the carrier of the present invention, it has become possible to effectively suppress the toner charge-up phenomenon particularly under low humidity.

The extracted amount of sodium hydroxide was 0.1 mol
1 g of the toner is weighed and added to 50 ml of an aqueous solution of 1 / liter sodium hydroxide, and then 50 rpm using a stirrer.
And uniformly disperse. After the dispersion treatment for 3 hours, the membrane filter (pore size: 0.45 μm)
m), and the absorbance of the obtained filtrate was measured.

Examples of the negative charge control agent include metal compounds of salicylic acid, dialkylsalicylic acid, naphthoic acid, dicarboxylic acid and derivatives thereof; high molecular weight compounds having sulfonic acid or carboxylic acid in the side chain; boron compounds; A urea compound; a silicon compound; and carricks arene are preferably used. As positive charge control agents,
For example, a quaternary ammonium salt; a polymer compound having the quaternary ammonium salt in a side chain; a guanidine compound; and an imidazole compound are preferably used. The content of the charge control agent is 0.5 to 10 with respect to 100 parts by mass of the binder resin.
It is preferably in parts by mass. However, the addition of the charge control agent to the toner particles is not essential.

The toner particles can be produced by melt-kneading a binder resin, a colorant, and other internal additives, cooling the kneaded material, pulverizing and classifying, or directly using a suspension polymerization method. A method for producing particles, a method for dispersion polymerization in which toner particles are directly produced using an aqueous organic solvent in which the obtained polymer is insoluble in a monomer, or a method in which polymerization is carried out directly in the presence of a water-soluble polar polymerization initiator. A method of producing toner particles using an emulsion polymerization method typified by a soap-free polymerization method for producing toner particles is exemplified.

In the present invention, the shape factor SF of the toner
It is preferable to use a method of producing toner particles by a suspension polymerization method, which can control -1 to 100 to 120, and relatively easily obtains a fine particle toner having a sharp particle size distribution and an appropriate weight average particle size.

When toner particles are produced by the polymerization method, 2,2′-azohis- (2,2
4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1,1'-azobis (cyclohexane-1-carbonitrile, 2,2'-azobis-4-methoxy-2,4-dimethylvalero Azo polymerization initiators such as nitrile and azobisisobutyronitrile; benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide;
A peroxide-based polymerization initiator such as lauroyl peroxide is used.

The amount of the polymerization initiator varies depending on the desired degree of polymerization.
0 mass% is added and used. The type of the polymerization initiator varies slightly depending on the polymerization method, but is used alone or in combination with reference to the 10-hour half-life temperature. Known crosslinking agents, chain transfer agents, polymerization inhibitors and the like for controlling the degree of polymerization can be further added and used.

In the case where suspension polymerization is used as a toner production method, tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, calcium carbonate, carbonate Examples include magnesium, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, and alumina. Examples of the organic compound include polyvinyl alcohol, gelatin, methylcellulose, methylhydroxypropylcellulose, ethylcellulose, sodium salts of carboxymethylcellulose, starch and the like. These are used by being dispersed in an aqueous phase. These dispersants are used in an amount of 0.2 to 100 parts by mass of the polymerizable monomer.
It is preferred to use 10.0 parts by weight.

As these dispersants, commercially available ones may be used as they are, but in order to obtain fine and uniform dispersed particles, the inorganic compound may be formed under high-speed stirring in a dispersion medium. I can do it. For example, in the case of tricalcium phosphate, a dispersant suitable for a suspension polymerization method can be obtained by mixing an aqueous solution of sodium phosphate and an aqueous solution of calcium chloride under high-speed stirring. Further, 0.001 to 0.1 parts by mass of a surfactant for miniaturization of these dispersants may be used in combination. Specifically, commercially available nonionic, anionic or cationic surfactants can be used, for example, sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, potassium stearate. Calcium oleate is preferably used.

In the case where the direct polymerization method is used for the production method of the toner, it is possible to specifically produce the toner by the following production method. A monomer composition obtained by adding a release agent, a colorant, a charge control agent, a polymerization initiator, and other additives made of a low-softening substance to a monomer and uniformly dissolving or dispersing the mixture using a homogenizer, an ultrasonic disperser, or the like. The product is dispersed in an aqueous phase containing a dispersion stabilizer using a conventional stirrer, homomixer, homogenizer, or the like. Preferably, the stirring speed and the time are adjusted so that the droplets composed of the monomer composition have a desired size of the toner particles, and the droplets are granulated. Thereafter, by the action of the dispersion stabilizer, the stirring may be performed to such an extent that the particle state is maintained and the sedimentation of the particles is prevented. The polymerization temperature is 40 ° C. or higher, generally 50 to 9
The polymerization is carried out at a temperature of 0 ° C. The temperature may be raised in the latter half of the polymerization reaction, and further, for the purpose of improving the durability properties, in order to remove unreacted polymerizable monomers and by-products, in the latter half of the reaction or after completion of the reaction, a part of the aqueous medium is distilled You may leave. After the reaction, the generated toner particles are collected by washing and filtration, and dried. In the suspension polymerization method, the monomer system 1 is usually used.
It is preferable to use 300 to 3000 parts by mass of water as a dispersion medium with respect to 00 parts by mass.

The toner may be classified to control the particle size distribution, and a multi-segment classifier utilizing inertial force is preferably used as the method. By using this apparatus, a toner having a preferable particle size distribution in the present invention can be efficiently produced.

Next, the image forming method of the present invention will be described.

In the image forming method of the present invention, the electrostatic image carrier is charged by a charging means, and the charged electrostatic image carrier is exposed to form an electrostatic image on the electrostatic image carrier. A toner image is formed on an electrostatic image carrier by developing the image with a developing unit having a two-component developer, and the toner image on the electrostatic image carrier is passed through an intermediate transfer member, or
The toner image is transferred onto the transfer material without any intervention, and the toner image on the transfer material is fixed by the heat and pressure fixing unit.

Hereinafter, the image forming method of the present invention will be described with reference to the accompanying drawings.

In FIG. 1, a magnetic brush composed of magnetic particles 23 is formed on the surface of the transfer sleeve 22 by the magnetic force of the magnet roller 21, and this magnetic brush contacts the surface of the electrostatic image carrier (photosensitive drum) 1. Then, the photosensitive drum 1 is charged. A charging bias is applied to the transport sleeve 22 by a bias applying unit (not shown). By irradiating the charged photosensitive drum 1 with laser light 24 by an exposure device (not shown), a digital electrostatic charge image is formed. The electrostatic charge image formed on the photosensitive drum 1 includes a magnet roller 12 and a two-component developer 19 carried on a developing sleeve 11 to which a developing bias is applied by a bias applying device (not shown). Is developed by the toner 19a.

The developing device 4 as a developing means includes a partition 17
, And is divided into a developer chamber R1 and a stirring chamber R2, and developer conveying screws 13 and 14 are provided respectively. Above the stirring chamber R2, a toner storage chamber R3 containing the toner 18 for replenishment is provided, and a replenishing port 20 is provided below the storage chamber R3.

The developer transport screw 13 rotates to transport the two-component developer 19 in the developer chamber R1 in one direction along the longitudinal direction of the developing sleeve 11 while stirring. The partition 17 is provided with openings (not shown) on the near side and the back side in the figure, and the two-component developer 19 conveyed to one side of the developer chamber R1 by the screw 13 passes through the opening of the partition 17 on one side. Is fed into the stirring chamber R2 through the developer transfer screw 14. The rotation direction of the screw 14 is opposite to that of the screw 13 and the stirring chamber R
The two-component developer 19 in 2, the two-component developer 19 transferred from the developer chamber R1, and the toner supplied from the toner storage chamber R3 are stirred and mixed in the opposite direction to the screw 13 while being mixed. The developer is conveyed in the chamber R2, and is sent into the developer chamber R1 through the other opening of the partition wall 17.

To develop the electrostatic charge image formed on the photosensitive drum 1, the developer 19 in the developer chamber R1 is pumped up by the magnetic force of the magnet roller 12, and the developing sleeve 1
1 is carried on the surface. The two-component developer 19 carried on the developing sleeve 11 is conveyed to the regulating blade 15 with the rotation of the developing sleeve 11, where it is regulated to a developer thin layer having an appropriate layer thickness. The photosensitive drum 1 reaches a development area facing the photosensitive drum 1. A magnetic pole (development pole) is provided at a portion of the magnet roller 12 corresponding to the development area.
N1 is located, and the developing pole N1 forms a developing magnetic field in the developing area, and the developer magnetically rises by the developing magnetic field,
A magnetic brush of the two-component developer 19 is generated in the development area. Then, the magnetic brush comes into contact with the photosensitive drum 1, and the toner 19a attached to the magnetic brush and the toner 19 attached to the surface of the developing sleeve 11 are formed by the reversal developing method.
a is transferred to and adheres to the region of the electrostatic charge image on the photosensitive drum 1, and the electrostatic charge image is developed to form a toner image.

The two-component developer 19 that has passed through the development area
Is returned into the developing device 4 with the rotation of the developing sleeve 11, is peeled off from the developing sleeve 11 by a repelling magnetic field between the magnetic poles S1 and S2, and the developer chamber R1 and the stirring chamber R2
Drops inside and is collected.

When the T / C ratio (mixing ratio of toner and carrier, that is, the toner concentration in the developer) of the two-component developer 19 in the developing device 4 is reduced by the above-described development, the toner 18 is transferred from the toner storage chamber R3 to the toner 18 Is supplied to the stirring chamber R2 in an amount corresponding to the amount consumed in the development, and the T /
C is kept at a predetermined amount. To detect the T / C ratio of the two-component developer 19 in the container 4, a toner concentration detection sensor that measures a change in the magnetic permeability of the two-component developer 19 using the inductance of the coil is used. The toner concentration detection sensor has a coil (not shown) therein.

The regulating blade 15 which is disposed below the developing sleeve 11 and regulates the layer thickness of the two-component developer 19 on the developing sleeve 11 is a non-magnetic blade 15 made of a non-magnetic material such as aluminum or SUS316. It is. The distance between the end and the surface of the developing sleeve 11 is 300 to
It is 1000 μm, preferably 400 to 900 μm.
If the distance is less than 300 μm, the magnetic carrier is clogged during this time, and the developer layer is likely to be uneven, and it is difficult to apply a two-component developer necessary for good development, and the density is low and there are many unevenness. An image is easily formed.
This distance is preferably 400 μm or more in order to prevent non-uniform application (so-called blade jam) due to unnecessary particles mixed in the developer. If this distance is larger than 1000 μm, the amount of the developer applied on the developing sleeve 11 increases, and it is difficult to regulate the predetermined thickness of the developer layer, and the adhesion of the magnetic carrier particles to the photosensitive drum 1 increases, and the developer The development regulation by the circulation and regulation blade 15 is weakened, so that the toner tribo is reduced and fogging is easily caused.

Even when the developing sleeve 11 is rotationally driven in the direction of the arrow, the magnetic carrier particle layer is separated from the surface of the sleeve by the balance between the restraining force based on magnetic force and gravity and the conveying force in the moving direction of the developing sleeve 11. Movement slows down. Some fall under the influence of gravity.

Accordingly, by appropriately selecting the arrangement positions of the magnetic poles N and S and the fluidity and magnetic properties of the magnetic carrier particles, the magnetic carrier particle layer becomes closer to the sleeve so that the magnetic pole N1 becomes closer to the sleeve.
To form a moving layer. Due to the movement of the magnetic carrier particles, the developer is conveyed to the developing area with the rotation of the developing sleeve 11 and is used for development.

The developed toner image is transferred onto a conveyed transfer material (recording material) 25 by a transfer blade 27 which is a transfer unit to which a transfer bias is applied by a bias applying unit 26, and is transferred onto the transfer material. The transferred toner image is fixed to a transfer material by a fixing device (not shown). In the transfer step, the transfer residual toner remaining on the photosensitive drum 1 without being transferred to the transfer material is adjusted in charge in the charging step, and is collected during development.

FIG. 3 is a schematic diagram in which the image forming method of the present invention is applied to a full-color image forming apparatus.

The main body of the full-color image forming apparatus includes a first image forming unit Pa, a second image forming unit Pb,
An image forming unit Pc and a fourth image forming unit Pd are provided side by side, and images of different colors are formed on a transfer material through a process of forming, developing, and transferring a latent image.

The configuration of each image forming unit provided in the image forming apparatus will be described by taking the first image forming unit Pa as an example.

The first image forming unit Pa includes an electrophotographic photosensitive drum 6 having a diameter of 30 mm as an electrostatic image carrier.
1a, the photosensitive drum 61a is rotated in the direction of arrow a. Reference numeral 62a denotes a primary charger as a charging unit, and a magnetic brush formed on the surface of a sleeve having a diameter of 16 mm is arranged so as to contact the surface of the photosensitive drum 61a. Reference numeral 67a denotes a laser beam for forming an electrostatic charge image on the photosensitive drum 61a, the surface of which is uniformly charged by the primary charger 62a, and is irradiated by an exposure device (not shown). 63a is the photosensitive drum 6
This is a developing device as a developing unit for developing a static toner image carried on 1a to form a color toner image, and holds a two-component developer having a carrier and a color toner. 64a is a belt-shaped transfer material carrier 6 for transferring the color toner image formed on the surface of the photosensitive drum 61a.
The transfer blade 64a is a transfer blade serving as a transfer unit for transferring the transfer material onto a surface of a transfer material (recording material) conveyed by the transfer member 8. The transfer blade 64a contacts a back surface of the transfer material carrier 68 to apply a transfer bias. What you get.

The first image forming unit Pa uniformly charges the photosensitive drum 61a with the primary charger 62a, forms an electrostatic image on the photosensitive member with the exposure device 67a, and transfers the formed electrostatic image to the photosensitive drum 61a. The developing device 63a develops the image with the two-component developer color toner, and the developed toner image is carried and transported by a first transfer section (a contact position between the photosensitive member and the transfer material). A transfer bias is applied from a transfer bias applying unit 60a to a transfer blade 64a that is in contact with the back surface side of the belt-shaped transfer material carrier 68, thereby transferring the image onto the surface of the transfer material.

When the toner is consumed by the development and the T / C ratio decreases, the decrease is detected by a toner concentration detection sensor 85 for measuring a change in the magnetic permeability of the developer using the inductance of the coil, and the toner is consumed. The supply toner 65 is supplied according to the toner amount. The toner density detection sensor 85 has a coil (not shown) therein.

The present image forming apparatus has the same configuration as the first image forming unit Pa, and has a second image forming unit Pb, a third image forming unit Pc, and a second image forming unit Pc having different colors of the color toner held in the developing device. Four image forming units of the fourth image forming unit Pd are provided side by side. For example, yellow toner is used for the first image forming unit Pa, magenta toner is used for the second image forming unit Pb, cyan toner is used for the third image forming unit Pc, and black toner is used for the fourth image forming unit Pd. The transfer of each color toner onto the transfer material is sequentially performed in the transfer section of each image forming unit. In this step, while the registration is being performed, each color toner is superimposed on the same transfer material by one transfer of the transfer material, and when the transfer is completed, the transfer material is separated from the transfer material carrier 68 by the separation charger 69. The sheet is sent to a fixing device 70, which is a heating / pressing fixing unit, by a conveying unit such as a conveying belt, and a final full-color image is obtained by a single fixing.

The fixing device 70 has a pair of a fixing roller 71 having a diameter of 40 mm and a pressure roller 72 having a diameter of 30 mm. The fixing roller 71 has heating means 75 and 76 therein.
have.

The unfixed color toner image transferred onto the transfer material passes through the pressure contact portion between the fixing roller 71 and the pressure roller 72 of the fixing device 70, and is applied to the transfer material by the action of heat and pressure. Is established.

In FIG. 3, the transfer material carrier 68 is an endless belt-like member, which is moved in the direction of arrow e by a driving roller 80.
79 is a transfer belt cleaning device, 81 is a belt driven roller, and 82 is a belt static eliminator. Reference numeral 83 denotes the transfer material in the transfer material holder,
8 is a pair of registration rollers for conveying the sheet to the registration rollers 8.

The transfer means is a contact transfer in which a transfer bias can be directly applied by contacting the back surface of a transfer material carrier such as a roller-shaped transfer roller instead of the transfer blade contacting the back surface of the transfer material carrier. Means can be used.

Further, in place of the above-mentioned contact transfer means, transfer is performed by applying a transfer bias from a corona charger arranged in a non-contact manner on the back side of a generally used transfer material carrier. It is also possible to use non-contact transfer means.

However, it is more preferable to use the contact transfer means in that the amount of ozone generated when the transfer bias is applied can be controlled.

Next, an example of another image forming method of the present invention will be described with reference to FIG.

FIG. 4 is a schematic diagram showing an example of an image forming apparatus capable of performing the image forming method of the present invention.

This image forming apparatus is configured as a full-color copying machine. As shown in FIG. 4, the full-color copying machine has a digital color image reader unit 35 at the upper part and a digital color image printer unit 36 at the lower part.

In the image reader section, the original 30 is placed on an original platen glass 31, and is exposed and scanned by an exposure lamp 32, so that a reflected light image from the original 30 is condensed on a full color sensor 34 by a lens 33, and a color image is formed. Obtain a decomposed image signal. The color separation image signal is processed by a video processing unit (not shown) through an amplification circuit (not shown), and is sent to a digital image printer unit.

In the image printer section, the photosensitive drum 1, which is an electrostatic image carrier, is, for example, an organic photoconductor (OPC).
And is rotatably supported in the direction of the arrow. Around the photosensitive drum 1, a pre-exposure lamp 41,
A corona charger 2 as a primary charging member, a laser exposure optical system 3 as a latent image forming means, a potential sensor 42, four developing devices 4Y, 4C, 4M, and 4K having different colors; The device 5A and the cleaning device 6 are arranged.

In the laser exposure optical system 3, an image signal from the reader unit is converted into an image scan exposure light signal by a laser output unit (not shown), and the converted laser light is reflected by the polygon mirror 3a. , Lens 3b
And is projected onto the surface of the photosensitive drum 1 via the mirror 3c.

At the time of image formation, the printer unit
Is rotated in the direction of the arrow, and after the charge is eliminated by the pre-exposure lamp 11, the photosensitive drum 1 is uniformly negatively charged by the charger 2 to irradiate a light image E for each separation color, and the latent image is formed on the photosensitive drum 1. To form

Next, the latent image on the photosensitive drum 1 is developed by operating a predetermined developing device, and a visible image, that is, a toner image is formed on the photosensitive drum 1 by using a resin-based negatively chargeable toner. I do. The developing devices 4Y, 4C, 4M, and 4K alternately approach the photosensitive drum 1 in accordance with each separated color and perform development by the operation of the eccentric cams 24Y, 24C, 24M, and 24K.

The transfer device 5A includes a transfer drum 5, a transfer charger 5b, a suction charger 5c for electrostatically attracting a recording material and a suction roller 5g opposed thereto, an inner charger 5d, an outer charger 5e, It has a separation charger 5h. The transfer drum 5 is rotatably supported so as to be rotatable, and a transfer sheet 5f, which is a recording material carrier for supporting a recording material (transfer material) in an opening area around the transfer drum 5, is integrally adjusted in a cylindrical shape. A polycarbonate film is used for the transfer sheet 5f.

The recording material is conveyed from the recording material cassette 7a, 7b or 7c to the transfer drum 5 through the recording material conveyance system, and is carried on the transfer sheet 5f. Transfer drum 5
The recording material carried thereon is repeatedly conveyed to a transfer position facing the photosensitive drum 1 as the transfer drum 5 rotates, and is transferred onto the photosensitive material by the action of the transfer charger 5b while passing through the transfer position. 1 is transferred.

In the above image forming step, yellow (Y),
By repeating the process for cyan (C), magenta (M), and black (K), a color image in which four color toner images are superimposed and transferred on the recording material on the transfer drum 5 is obtained.

In the case of single-sided image formation, the recording material onto which the four color toner images have been transferred in this way is separated by the action of the separation claw 8a, the separation push-up roller 8b, and the separation charger 5h.
The sheet is separated from the transfer drum 5 and sent to the heat fixing device 9.
The heat fixing device 9 includes a heat fixing roller 9a having a heating unit therein and a pressure roller 9b. The full-color image carried on the recording material is fixed on the recording material by passing the recording material through the pressure contact portion between the heat fixing roller 9a and the pressure roller 9b as a heating member. That is, in this fixing step, toner color mixing, color development, and fixing to the recording material are performed to form a full-color permanent image, which is then discharged to the tray 10 to complete one full-color copy. On the other hand, the photosensitive drum 1 is subjected to the image forming process again after the residual toner on the surface is cleaned and removed by the cleaning device 6.

In the image forming method of the present invention, a toner image obtained by developing the electrostatic image formed on the latent image carrier can be transferred to a recording material via an intermediate transfer member.

That is, in this image forming method, the toner image formed by developing the electrostatic image formed on the electrostatic image carrier is transferred to the intermediate transfer member, and the toner image transferred to the intermediate transfer member is developed. Is transferred to a recording material.

An example of an image forming method using an intermediate transfer member will be specifically described with reference to FIG.

In the apparatus system shown in FIG. 5, the cyan developing device 54-1, the magenta developing device 54-2, the yellow developing device 54-3, and the black developing device 54-4 are respectively provided with a cyan developer containing a cyan toner and a magenta developer. A magenta developer having a toner, a yellow developer having a yellow toner, and a black developer having a black toner have been introduced. An electrostatic latent image is formed on a photosensitive member 51 as a latent image holding member by a latent image forming means 53 such as a laser beam. By a developing method such as a magnetic brush developing method, a non-magnetic one-component developing method or a magnetic jumping developing method,
The electrostatic charge image formed on the photoconductor 51 is developed with these developers, and a toner image of each color is formed on the photoconductor 51.
The photosensitive member 51 is a photosensitive drum or a photosensitive belt having a conductive substrate 51b and a photoconductive insulating material layer 51a such as amorphous selenium, cadmium sulfide, zinc oxide, an organic photoconductor, and amorphous silicon formed on the conductive substrate 51b. is there. The photoconductor 51 is rotated in a direction indicated by an arrow by a driving device (not shown). As the photoconductor 51, a photoconductor having an amorphous silicon photosensitive layer or an organic photosensitive layer is preferably used.

The organic photosensitive layer may be a single layer type in which the photosensitive layer contains a charge generating substance and a substance having charge transporting ability in the same layer, or a functional separation type in which the charge transporting layer contains the charge generating layer as a component. It may be a photosensitive layer. A laminated photosensitive layer having a structure in which a charge generation layer and then a charge transport layer are laminated on a conductive substrate in this order is one of preferred examples.

As the binder resin for the organic photosensitive layer, a polycarbonate resin, a polyester resin, or an acrylic resin has good cleaning properties, and poor cleaning, fusion of the toner to the photosensitive member, and filming of the external additive hardly occur.

In the charging step, there are a non-contact type with the photoreceptor 51 using a corona charger and a contact type with a contact charging member such as a roller, and both types are used. For efficient uniform charging, simplification, and low ozone generation, a contact type as shown in FIG. 5 is preferably used.

The charging roller 52 as a primary charging member includes:
The central conductive wire 52b and the conductive elastic layer 5 forming the outer periphery thereof
2a as a basic configuration. Charging roller 52
Is pressed against the surface of the photoconductor 51 with a pressing force, and the photoconductor 5
The rotation follows the rotation of 1.

A preferable process condition when the charging roller is used is that the contact pressure of the roller is 4.9 to 490 N
/ M (5 to 500 g / cm), when an AC voltage is superimposed on a DC voltage, the AC voltage is 0.5 to 5
kVpp, AC frequency = 50 Hz to 5 kHz, DC voltage = ± 0.2 to ± 5 kV.

Other contact charging members include a method using a charging blade and a method using a conductive brush. These contact charging members are effective in that high voltage is not required and generation of ozone is reduced.

The material of the charging roller and the charging blade as the contact charging member is preferably conductive rubber, and a release coating may be provided on the surface thereof. As the release coating, a nylon resin, PVDF (polyvinylidene fluoride), PVDC (polyvinylidene chloride), or a fluorine acrylic resin can be used.

The toner image on the photosensitive member is applied with a voltage (for example, ±
(0.1 to ± 5 kV). The intermediate transfer member 55 includes a pipe-shaped conductive core 55b and a medium-resistance elastic layer 55 formed on the outer peripheral surface thereof.
a. The cored bar 55b may be provided with a conductive layer (for example, conductive plating) on the surface of plastic.

The medium-resistance elastic layer 55a is formed of silicone rubber, Teflon (registered trademark) rubber, chloroprene rubber, urethane rubber, EPDM (ethylene propylene diene).
An electrical resistance value (volume resistivity) of 10 ⁵ to 10 ¹¹ by blending and dispersing a conductivity-imparting material such as carbon black, zinc oxide, tin oxide, and silicon carbide in an elastic material such as
It is a solid or foamed layer adjusted to a medium resistance of Ω · cm.

The intermediate transfer member 55 is provided in parallel with the photosensitive member 51 so as to be in contact with the lower surface of the photosensitive member 51, and is arranged in the counterclockwise direction indicated by an arrow at the same peripheral speed as the photosensitive member 51. Rotate.

The first color toner image formed and carried on the surface of the photosensitive member 51 is transferred by the transfer bias applied to the intermediate transfer member 55 in the process of passing through the transfer nip portion where the photosensitive member 51 and the intermediate transfer member 55 are in contact with each other. The intermediate transfer is sequentially performed on the outer surface of the intermediate transfer body 55 by the electric field formed in the nip area.

The untransferred toner on the photosensitive member 51 that has not been transferred to the intermediate transfer member 55 is transferred to the photosensitive member cleaning member 5.
8 and is collected in the photoconductor cleaning container 59.

A transfer means is provided in parallel with the intermediate transfer body 55 and is brought into contact with the lower surface of the intermediate transfer body 55. The transfer means 57 is, for example, a transfer roller or a transfer belt. It rotates clockwise with the same peripheral speed as the arrow. The transfer means 57 may be provided so as to directly contact the intermediate transfer body 55, or a belt or the like may be provided so as to contact between the intermediate transfer body 55 and the transfer means 57.

In the case of the transfer roller, the transfer roller is basically composed of a central core bar 57b and a conductive elastic layer 57a formed on the outer periphery thereof.

For the intermediate transfer member and the transfer roller, general materials can be used. By setting the volume resistivity of the elastic layer of the transfer roller smaller than the volume resistivity of the elastic layer of the intermediate transfer body, the voltage applied to the transfer roller can be reduced, and a good toner image can be formed on the transfer material. In addition, it is possible to prevent the transfer material from being wound around the intermediate transfer member. In particular, it is particularly preferable that the volume specific resistance of the elastic layer of the intermediate transfer member is at least 10 times the volume specific resistance of the elastic layer of the transfer roller.

The hardness of the intermediate transfer member and the transfer roller is J
It is measured in accordance with IS K-6301. The intermediate transfer member used in the present invention is preferably composed of an elastic layer belonging to the range of 10 to 40 degrees. On the other hand, the hardness of the elastic layer of the transfer roller is higher than the hardness of the elastic layer of the intermediate transfer member. Those having a value of from -80 degrees are preferred in order to prevent the transfer material from winding around the intermediate transfer member. When the hardness of the intermediate transfer body and that of the transfer roller are reversed, a concave portion is formed on the transfer roller side, and the winding of the transfer material around the intermediate transfer body is likely to occur.

The transfer means 57 rotates the intermediate transfer member 55 at a constant speed or at a different peripheral speed. The transfer material 56 is conveyed between the intermediate transfer body 55 and the transfer means 57,
The toner image on the intermediate transfer body 55 is transferred to the surface of the transfer material 56 by applying a bias having a polarity opposite to the frictional charge of the toner to the transfer unit 57 from the transfer bias unit.

The untransferred toner remaining on the intermediate transfer member that has not been transferred to the transfer material 56 is removed by the cleaning member 6 for the intermediate transfer member.
0 and is collected in the intermediate transfer body cleaning container 62. The toner image transferred to the transfer material 56 is fixed on the transfer material 56 by the heat fixing device 61.

As the material of the transfer roller, the same material as that of the charging roller can be used. The preferable transfer process condition is that the contact pressure of the roller is 2.94 to 490.
N / m (3 to 500 g / cm) (more preferably, 19.
6 to 294 N / m), DC voltage = ± 0.2 to ± 10 k
V.

When the linear pressure as the contact pressure is less than 2.94 N / m, it is not preferable because the transfer of the transfer material and the occurrence of transfer failure tend to occur.

For example, the conductive elastic layer 5 of the transfer roller 57
7b is an elastic material such as polyurethane rubber or EPDM (ethylene propylene diene terpolymer), and a conductive agent such as carbon black, zinc oxide, tin oxide or silicon carbide mixed and dispersed in the material to obtain an electric resistance value (volume resistivity). ) From 10 ⁶
It is a solid or foamed layer adjusted to have a medium resistance of 10 ¹⁰ Ω · cm.

Although not shown, it is preferable that the image forming apparatus shown in FIGS. 3 to 5 be provided with an atmosphere heater for controlling the inside of the apparatus to a constant temperature.

That is, by controlling the inside of the apparatus to a constant temperature, the charging of the developing toner in the present invention becomes stable,
Transferability is improved. In particular, in the image forming apparatus shown in FIG. 3, the charge adjustment of the transfer residual toner becomes easy, and the toner can be efficiently collected at the time of development.

As the heater, a heating element may be used. More specifically, an electric resistance heating element such as a wound heater of a sheath-shaped heater, a plate-shaped heater, and a ceramic heater, and a heat radiation element such as a halogen lamp and an infrared lamp. Examples of the heating element include a lamp heating element, a heating element using heat exchange means using a liquid, a gas, or the like as a heating medium. As the surface material of the heating element, metals such as stainless steel, nickel, aluminum, and copper, ceramics, heat-resistant polymer resin, and the like can be used. Regarding the temperature control of the heating element, any of the methods of installing a thermoswitch near the heating element and controlling the temperature by sensing the temperature in the vicinity may be used.

[0200]

The present invention will now be described in detail with reference to Examples, but it should not be construed that the present invention is limited thereto.

Carrier Production Example 1 Phenol 7.5 parts by mass Formalin solution 11.25 parts by mass (formaldehyde about 40%, methanol about 10%, balance water) γ-glycidoxypropyltrimethoxysilane 1.0 53% by mass of magnetite fine particles treated with lipophilic treatment by mass% (average particle size: 0.30 μm, specific resistance: 4.7 × 10 ⁵ Ω · cm) ・ γ-glycidoxypropyltrimethoxysilane: 1.0 mass% 35 parts by mass of oiled α-Fe ₂ O ₃ fine particles (average particle size 0.51 μm, specific resistance 2.3 × 10 ⁹ Ω · cm)

The magnetite and α-Fe ₂ O used here
The lipophilic treatment of ₃ was carried out by using 99 parts by mass of magnetite and α-Fe
1.0 parts by weight for each ₂ O ₃ 99 parts by γ-
Glycidoxypropyltrimethoxysilane was added, and the mixture was premixed and stirred at 100 ° C. for 30 minutes in a Henschel mixer.

The above materials and 11 parts by weight of water were mixed at 40 ° C. for 1 hour. 2.0 parts by mass of 28% by mass ammonia water as a basic catalyst and 11 parts by mass of water were added to the slurry, and the mixture was heated and maintained at 85 ° C. for 40 minutes with stirring and mixing, and reacted for 3 hours.
A phenolic resin was formed and cured. Thereafter, the mixture was cooled to 30 ° C., 100 parts by mass of water was added, the supernatant was removed, and the precipitate was washed with water and air-dried. Next, this was dried at 140 ° C. under reduced pressure (5 mmHg or less) to obtain spherical magnetic carrier core particles containing magnetite fine particles using a phenol resin as a binder resin.

[0204] The particles are removed by coarse sieves through sieves of 60 mesh and 100 mesh, and then a multi-split air classifier utilizing the Coanda effect (Eppo Jet Lab EJ-L-3, manufactured by Nippon Mining Co., Ltd.) Was used to remove fine powder and coarse powder to obtain carrier core particles.

The obtained carrier core particles were put into a coater, and 0.3% by mass of γ-aminopropyltrimethoxysilane diluted with a toluene solvent was treated on the core surface while continuously applying a shearing stress. did. At that time, 4
Treatment at 0 ° C. and 101080 Pa (760 Torr) for 10 minutes, and then 39900 Pa over 10 minutes
(300 Torr) under reduced pressure and in a dry nitrogen stream while evaporating the solvent. Subsequently, 0.5% by mass of a straight silicone resin in which all the substituents are methyl groups, and 0.5% of γ-aminopropyltrimethoxysilane.
The mixture of 01% by mass was coated with toluene as a solvent.
At that time, first, 1/3 of the mixture was heated at 40 ° C. and 101080
The treatment was performed at Pa (760 Torr) for 10 minutes, and then the pressure was reduced to 66500 Pa (500 Torr) over 10 minutes, and the solvent was evaporated under a dry nitrogen stream. This operation was repeated twice for each 1/3 of the mixture, and the remaining 2/3 of the treatment was performed.

Further, this magnetic coated carrier was
C., baked at 100.degree. C., and agglomerated coarse particles were cut with a 100-mesh sieve, and then fine and coarse powders were removed with a multi-split air classifier to adjust the particle size distribution.

Thereafter, the humidity was adjusted for 100 hours in a hopper maintained at 23 ° C. and 60%, and the magnetic coat carrier No. 1 was obtained. The obtained magnetic coated carrier No. Table 1 shows the production method 1 and Table 2 shows the physical properties.

Carrier Production Example 2 In Carrier Production Example 1, the ratio of magnetite to hematite was changed to a ratio of 70:30, and the core drying temperature was changed to 1%.
Except for performing at 60 ° C., the same procedure as in Carrier Production Example 1 was carried out. 2 was obtained. The obtained magnetic coated carrier No. Table 2 shows the production method of No. 2 and Table 2 shows the physical properties.

Carrier Production Example 3 In Carrier Production Example 2, 10108 of aminosilane was added.
13300 after treatment at 0 Pa (760 Torr) for 10 minutes
The magnetic coated carrier No. was the same as in Carrier Production Example 2 except that the treatment was carried out under reduced pressure to Pa (100 Torr). 3 was obtained. The obtained magnetic coated carrier No. Table 1 shows the production method of No. 3 and Table 2 shows the physical properties.

Carrier Production Example 4 In Carrier Production Example 2, the ratio of magnetite to hematite was set to 100: 0 and the surface treatment was performed using magnetite treated with γ-aminopropyltrimethoxysilane, and the drying temperature was adjusted to 200 ° C. To manufacture the core. 0.15% by mass of aminosilane was treated in the same manner as in Carrier Production Example 3 to obtain 0.25% of methylsilicone and 0.1% of aminosilane.
005% at 101080 Pa (760 Torr)
After performing the magnetic coating carrier No. 1 in the same manner as in Carrier Production Example 2, except that the pressure is reduced to 39900 Pa (300 Torr) after the treatment, the processing is changed to 39900 Pa (300 Torr). 4 was obtained. The obtained magnetic coated carrier No. Table 1 shows the manufacturing methods of Table 4.
Table 2 shows the physical properties.

Carrier Production Example 5 A carrier is produced in the same manner as in Carrier Production Example 1, except that the ratio of magnetite to hematite is 40:60. After that,
The same as in Carrier Production Example 3 except that in Carrier Production Example 3, the amount of methyl silicone was changed to 1.5% by mass and that of aminosilane was changed to 0.03% by mass. 5 was obtained. Obtained magnetic coated carrier N
o. Table 1 shows the production method of No. 5, and Table 2 shows the physical properties.

Carrier Production Example 6 In Carrier Production Example 3, the core was dried at 200 ° C.
, Except that the carrier was changed to the carrier-coated carrier No. 3 in the same manner as in Carrier Production Example 3. 6 was obtained. The obtained magnetic coated carrier No. Table 1 shows the production method of No. 6 and Table 2 shows the physical properties.

Carrier Production Example 7 In Carrier Production Example 3, the core was dried at 150 ° C.
As a result, core particles were obtained. Thereafter, 0.2% by mass of aminosilane was treated at normal pressure, and further, methyl silicone resin was added in an amount of 0.1%.
Except that 35% by mass and 0.007% by mass of aminosilane were treated at normal pressure, the same procedure as in Carrier Production Example 3 was carried out except that the magnetic coated carrier No. 3 was used. 7 was obtained. The obtained magnetic coated carrier No. Table 1 shows the production method of No. 7, and Table 2 shows the physical properties.

Carrier Production Example 8 In Carrier Production Example 7, 0.3% by mass of aminosilane was used.
Immediately after the addition, the pressure was reduced to 39,900 Pa (300 Torr) and the treatment was further performed.
(300 Torr), except that the treatment was carried out under reduced pressure. 8 was obtained. The obtained magnetic coated carrier No. 8
Is shown in Table 1 and the physical properties are shown in Table 2.

Carrier Production Example 9 In Carrier Production Example 7, the ratio of magnetite to hematite was set to 50:50, a core was obtained at a drying temperature of 250 ° C., 0.15% by mass of aminosilane was treated at normal pressure, and methyl silicone was added at 0%. 0.25% by mass, aminosilane 0.2.
005% by mass of the magnetic coated carrier No. 7 in the same manner as in Carrier Production Example 7 except that the carrier was treated at normal pressure. 9 was obtained. The obtained magnetic coated carrier No. Table 1 shows the production method of No. 9 and Table 2 shows the physical properties.

Carrier Production Example 10 In Carrier Production Example 3, 0.6% by mass of aminosilane was used.
Was treated at 101080 Pa (760 Torr) for 10 minutes, the pressure was reduced to 79800 Pa (600 Torr), and the solvent was removed.
Aminosilane 0.05% by mass is added to 101080 Pa (76
0 Torr) for 10 minutes and then 79800 Pa (60
The pressure is reduced to 0 Torr and the solvent is removed. In addition,
Except that the subsequent baking is performed at 120 ° C,
Magnetic coated carrier N in the same manner as in Carrier Production Example 3
o. 10 was obtained. The obtained magnetic coated carrier No. 1
Table 1 shows the production method of No. 0, and Table 2 shows the physical properties.

Carrier Production Example 11 In Carrier Production Example 3, 0.1% by mass of aminosilane was used.
Was treated at 101080 Pa (760 Torr) for 10 minutes, the pressure was reduced to 13300 Pa (100 Torr), and the solvent was removed.
0.006% by mass of aminosilane is added to 101080 Pa (7
After processing at 60 Torr (10 Torr) for 10 minutes, 13300 Pa (1
(00 Torr) to remove the solvent. Further, except that the subsequent baking is performed at 200 ° C., the same procedure as in Carrier Production Example 3 was carried out. 11 was obtained. The obtained magnetic coated carrier No.
Table 1 shows the production methods of No. 11 and Table 2 shows the physical properties.

Carrier Production Example 12 In Carrier Production Example 11, aminosilane was changed to 0.9% by mass, methyl silicone was further changed to 1.5% by mass, and aminosilane was changed to 0.03% by mass.
C. except that the carrier was performed at a magnetic coating carrier No. 11 in the same manner as in Carrier Production Example 11. 12 was obtained. The obtained magnetic coated carrier No. Table 1 shows the production methods of No. 12, and Table 2 shows the physical properties.

Carrier Production Example 13 In Carrier Production Example 3, 0.1 mass% of aminosilane was used.
Was treated at 101080 Pa (760 Torr) for 10 minutes, the pressure was reduced to 66500 Pa (500 Torr), and the solvent was removed.
0.002% by mass of aminosilane was added to 101080 Pa (7
After processing at 60 Torr (10 Torr) for 10 minutes, 66500 Pa (5
00 Torr), except that the solvent was removed by reducing the pressure. 13 was obtained. The obtained magnetic coated carrier No.
Table 1 shows the production methods of No. 13 and Table 2 shows the physical properties.

Carrier Production Example 14 In Carrier Production Example 3, the particle size of magnetite was set to 0.1.
Except that the particle size of the hematite was changed to 0.64 μm, the magnetic coated carrier No. was changed in the same manner as in Carrier Production Example 3. 14 was obtained. The obtained magnetic coated carrier No. Table 1 shows the production method of No. 14, and Table 2 shows the physical properties.

Carrier Production Example 15 In Carrier Production Example 3, the particle size of magnetite was set to 0.1.
Except that the particle size of hematite was changed to 0.40 μm, the magnetic coated carrier No. was changed in the same manner as in Carrier Production Example 3. 15 was obtained. The obtained magnetic coated carrier No. Table 1 shows the production methods of No. 15 and Table 2 shows the physical properties.

Production Example 1 of Toner (Pulverized Toner 1 ) 100 parts by mass of polyester resin (condensed polymer of propoxylated bisphenol A and fumaric acid, acid value 10.8 mg KOH / g) I. Pigment Blue 15:35 5 parts by mass ・ Aluminum compound of dialkylsalicylic acid 5 parts by mass ・ Low molecular weight polypropylene 5 parts by mass To perform melt kneading. This melt-kneaded material was crushed by a hammer mill to obtain a crushed material having a mesh path of 1 mm. Further, after finely pulverizing with a jet mill, classification was performed with a multi-segment classifier (Elbow Jet) to obtain cyan toner particles.

To 100 parts by mass of the cyan toner particles, 1.2 parts by mass of hydrophobized titanium oxide fine powder (number average particle size of primary particles: 0.02 μm) was mixed using a Henschel mixer, and the weight average particle size was adjusted. 7.5 μm cyan toner No. 1 was obtained. The obtained toner No. Table 3 shows the composition and physical properties of No. 1.

Toner Production Example 2 (Pulverized Toner 2) A styrene-n-butyl acrylate copolymer resin (acid value 0 ) was used in place of the polyester resin used in Toner Production Example 1.
mgKOH / g, Mw30000, Mn9000) 10
Using 0 parts by mass, 1.2 parts by mass of hydrophobically treated silica fine powder (number average particle size of primary particles: 0.03 μm) is mixed with 100 parts by mass of the cyan toner particles by using a Henschel mixer. In the same manner as in toner production example 1, cyan toner No. 2 was obtained. The obtained toner No. Table 3 shows the composition and physical properties of Sample No. 2.

Toner Production Example 3 (Pulverized Toner 3) Cyan toner No. 1 was prepared in the same manner as in Production Example 1 of toner except that the aluminum compound of dialkylsalicylic acid used in Production Example 1 of Toner was not added. 3 was obtained. The obtained toner No. Table 3 shows the composition and physical properties of No. 3.

Toner Production Example 4 (Pulverized Toner 4) A cyan toner production example 1 was used, except that calixarene was used in place of the aluminum compound of dialkylsalicylic acid used in toner production example 1. Toner No. 4 was obtained. The obtained toner No. Table 3 shows the composition and physical properties of Sample No. 4.

Toner Production Example 5 (Polymerized Toner 5) 450 parts by mass of a 0.1 M Na ₃ PO ₄ aqueous solution was charged into 710 parts by mass of ion-exchanged water, and heated to 60 ° C.
1200 using a homo homomixer (manufactured by Tokushu Kika Kogyo)
The mixture was stirred at 0 rpm. To this, 68 parts by mass of a 1.0 M CaCl ₂ aqueous solution was gradually added to obtain an aqueous medium containing Ca ₃ (PO ₄ ) ₂ .

On the other hand, styrene 165 parts by mass n-butyl acrylate 35 parts by mass C.I. I. Pigment Blue 15: 3 (coloring agent) 15 parts by mass ・ Dialkylsalicylic acid metal compound (charge controlling agent) 5 parts by mass ・ Saturated polyester (polar resin) 10 parts by mass ・ Ester wax (melting point 70 ° C.) 50 parts by mass C., and uniformly dissolved and dispersed at 11,000 rpm using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.). Into this, 10 parts by mass of a polymerization initiator 2,2′-azobis (2,4-dimethylvaleronitrile) was dissolved to prepare a polymerizable monomer composition.

The polymerizable monomer composition was placed in an aqueous medium, and the mixture was stirred at 60 ° C. under a N ₂ atmosphere at 11,000 rpm for 10 minutes using a TK homomixer to form a polymerizable monomer composition. Granulated. Thereafter, while stirring with a paddle stirring blade, the temperature was raised to 80 ° C., and the reaction was performed for 10 hours. After completion of the polymerization reaction, the remaining monomer was distilled off under reduced pressure, and after cooling, hydrochloric acid was added to dissolve calcium phosphate, followed by filtration, washing with water,
After drying, cyan toner particles were obtained. Hydrophobized silica fine powder (number average particle size of primary particles: 0.03 μm) was added to 100 parts by mass of the obtained cyan toner particles.
6 parts by mass of cyan toner No. 1 having a weight average particle size of 7.8 μm. 5 was obtained. The obtained toner No. Table 3 shows the composition and physical properties of No. 5.

Toner Production Example 6 (Polymerized Toner 6) Hydrophobized alumina fine powder (number average particle diameter of primary particles: 0.1 μm) was used in place of the hydrophobized silica fine powder used in Toner Production Example 6. Except for using 1.2 parts by mass, cyan toner No. was produced in the same manner as in Production Example 6 of the toner.
7 was obtained. The obtained toner No. Table 3 shows the composition and physical properties of No. 6.

Toner Production Example 7 (Polymerized Toner 7) I. Pigment Blue 1
Magenta Toner No. 5 in the same manner as in Production Example 5 of the toner except that 8 parts by mass of quinacridone was used instead of 5: 3. 7 was obtained. The obtained toner No. Table 3 shows the composition and physical properties of No. 7.

Toner Production Example 8 (Polymerized Toner 8) The C.I. I. Pigment Blue 1
5: 3, except that 6.5 parts by mass of Pigment Yellow 93 was used in the same manner as in Production Example 5 of the toner. 8 was obtained. The obtained toner No.
Table 3 shows the composition and physical properties of No. 8.

Production Example 9 of Toner (Polymerized Toner 9) I. Pigment Blue 1
Black toner No. 5 was manufactured in the same manner as in Production Example 5 of toner except that 10 parts by mass of carbon black was used instead of 5: 3. 9 was obtained. The obtained toner No. Table 3 shows the composition and physical properties of No. 9.

[0234]

[Table 1]

[0235]

[Table 2]

[0236]

[Table 3]

[Example 1] Carrier no. 1 and toner N
o. 5 was mixed so that the ratio of the toner to the total mass was 8% by mass to produce a two-component developer A.

Using the obtained two-component developer A in an image forming apparatus modified from a commercial copying machine GP55 (manufactured by Canon Inc.), image formation was performed, and transfer efficiency, charge stability, toner scattering, fog, image An evaluation was made for the concentration. The respective measurement conditions and evaluation criteria are shown below.

The evaluation environment was normal temperature and low humidity (23 ° C./5% R
H), and in each environment of normal temperature and normal humidity (23 ° C./60% RH).

The transfer efficiency was evaluated at normal temperature and normal humidity. First, a solid black image is formed on a photosensitive drum, the solid black image is collected with a transparent adhesive tape, and the image density (D1) is measured using a color reflection densitometer (col).
or reflection densitometer
X-RITE 404A manufactured
by X-Rite Co. ). Next, a solid black image is formed again on the photosensitive drum, the solid black image is transferred to a recording material, the solid black image transferred on the recording material is collected with a transparent adhesive tape, and its image density (D2 ) Was measured. The transfer efficiency was calculated from the obtained image densities (D1) and (D2) based on the following equation.

Transfer efficiency (%) = (D2 / D1) × 100

The charge stability was evaluated by conducting a copy test of 50,000 sheets under normal temperature and low humidity, and evaluating the charge stability from the change in the charge amount of the developer. The evaluation was performed according to the following evaluation criteria, in which the change amount of the charge amount at the time of copying 1000 sheets and the change amount of the charge amount at the end of the copy were expressed in%. (Evaluation Criteria) A: Change in charge amount is 0% to less than 11% B: Change in charge amount is 11% to less than 20% C: Change in charge amount is 21% to less than 30% D: Charge amount E: the change width of the charge amount is 41% to less than 50% F: the change width of the charge amount is 51% or more

For toner scattering, the developing device is taken out after 50,000 sheets of image have been output at normal temperature and low humidity, and set in an idle rotating machine. Place A4 paper under the sleeve of the developing unit
After idle rotation for 0 minutes, the weight of the toner dropped on the paper was measured and evaluated according to the following criteria. (Evaluation criteria) A: Less than 4 mg B: 4 mg to less than 7 mg C: 7 mg to less than 10 mg D: 10 mg to less than 13 mg E: 13 mg to less than 16 mg F: 16 mg or more

Regarding fog, images were taken at normal temperature and low humidity by using a reflection densitometer (densitometer TC6MC:
(Tokyo Denshoku Technical Center) was used to measure the reflection density of blank paper and the reflection density of the non-image area of the paper of the copying machine, and the difference between the two reflection densities was evaluated with reference to the reflection density of blank paper. . (Evaluation criteria) A: less than 0.6% B: 0.6 to less than 1.1% C: 1.1 to less than 1.6% D: 1.6 to less than 2.1% E: 2.1 to less Less than 4.1% F: 4.1% or more

The image density was measured at normal temperature and low humidity by copying a solid black image at the initial stage and after the completion of 50,000 copies, and measuring the density with a color reflection densitometer (color reflectometer).
ion densitometer X-Rite 4
04A manufactured by X-Rit
e Co. ). Table 4 shows the evaluation results.

[Examples 2 to 13 and Comparative Examples 1 to 5] Table 4
The two-component developers B to T were produced in the same manner as in Example 1 except that the combination of the carrier and the toner as shown in Example 1 was used. Table 4 shows the evaluation results.

[0247]

[Table 4]

[Embodiment 14] The carrier no. 1 and toner no. 5 was mixed so that the ratio of the toner to the total mass was 8% by mass to produce a two-component developer A.

Toner No. 5 in place of toner no.
7, toner no. 8 and toner no. 9 was used to produce two-component developers V, U and W.

The resulting four-color two-component developers V, U, and A
And W were charged into the developing devices 63a, 63b, 63c and 63d of the full-color image forming apparatus shown in FIG. 3, respectively, and a full-color image was formed under the following conditions. In copying, a full-color image having a stable image density was obtained.

(Image Forming Conditions) In the charging step, OP
The following magnetic particles 23 were used for the magnetic brush charging device for charging the C photosensitive drum.

Preparation of Magnetic Particles 5 parts by mass of MgO, 8 parts by mass of MnO, 4 parts by mass of SrO, F
After 83 parts by mass of e ₂ O ₃ were each atomized, water was added and mixed, the mixture was granulated, fired at 1300 ° C., the particle size was adjusted, and ferrite magnetic particles having an average particle size of 28 μm (σ
_79.6 is 60 Am ² / kg, coercive force is 4.38 × 10 ^-1 k
A / m [= 55 Oersted]).

A mixture of 100 parts by mass of the above magnetic particles and 10 parts by mass of isopropoxytriisostearoyl titanate in 99 parts by mass of hexane / 1 part by mass of water was mixed so that the treatment amount became 0.1 part by mass. The treatment yielded magnetic particles.

The magnetic particles have a volume resistance of 3 × 10 ⁷ Ω.
Cm.

In the charging device, the photosensitive drum 1 is rotated in the counter direction at a peripheral speed of 120% with respect to the peripheral speed of the photosensitive member, and a DC / AC electric field (-700 V, 1 kHz / 1.
2 kVpp) was applied, and the photosensitive drum 1 was charged. An original image having an image area of 30% was digitally processed, and a digital latent image was formed on the OPC photosensitive drum as an electrostatic image.

The developing devices 63a, 63b, 63c and 63
As d, the developing device 4 shown in FIG. 1 was used.
An electrostatic charge image was developed by a reversal developing method using a negatively chargeable color toner. As the developing bias applied to the developing sleeve, a DC / AC voltage (-300 V, 8 kHz / 2 kVpp) using the discontinuous AC bias voltage shown in FIG. 2 is superimposed, and the developing contrast is set to 200 V, and the fog removal reversal contrast is set to -150 V. did.

The color toner image formed on the photosensitive drum 1 is transferred to a first transfer section (a contact position between the photosensitive member and the transfer material).
By applying a transfer current of −15 μA from the transfer bias applying means 60a to the transfer blade 64a, the transfer is performed on the surface of the transfer material, and further in the second transfer section, the third transfer section, and the fourth transfer section. Multiple transfer of the color toner image was performed on the transfer material.

In the heat and pressure fixing device, a heating roller coated with a PFA resin to a layer thickness of 1.2 μm was used, and a PFA resin was coated to a layer thickness of 1.2 μm as the pressure roller.
Was used. The silicone oil applying means was removed from the heat and pressure fixing device, and oilless fixing was performed.

Example 18 The four-component two-component developers V, A, U and W produced in Example 17 were used as developing devices 4Y, 4C, 4M and 4 in the full-color image forming apparatus shown in FIG.
K, and a DC / AC voltage (-500 V, 12 V) using a discontinuous AC bias voltage for the developing sleeve.
kHz / 2 kVpp), the developing contrast was set to 270 V, the fog removal reversal contrast was set to −120 V, and a full-color image was formed by transfer current of 17 μA and oil-less fixing. A good full-color image was obtained. In addition, a full-color image having a stable image density was obtained even in multiple-sheet copying.

[Embodiment 19] The four-color two-component developers A, U, V and W produced in Embodiment 17 were used as developing units 54-1 and 54-2 of the full-color image forming apparatus shown in FIG. 5
4-3 and 54-4, respectively, and a DC / AC voltage (-350 V, 3 kHz / 1.8 kVpp) using a discontinuous AC bias voltage is applied to the developing sleeve in a superimposed manner, and a developing contrast of 250 V and fogging are removed. Invert contrast was set to -150V, and transfer current was 15μ
A: When a full-color image was formed by oil-less fixing, a good full-color image was obtained, and a full-color image having a stable image density was obtained even when copying a large number of sheets.

[0261]

According to the present invention, a carrier having excellent durability, having excellent charge-imparting properties to toner, and enabling a high-quality image to be obtained even when copying a large number of sheets.

[Brief description of the drawings]

FIG. 1 is a schematic view illustrating a preferred example of an image forming method of the present invention.

FIG. 2 is a diagram showing an alternating electric field used in Example 1.

FIG. 3 is a schematic explanatory view showing an example of a full-color image forming method.

FIG. 4 is a schematic explanatory view showing another example of the image forming apparatus for performing the image forming method of the present invention.

FIG. 5 is a schematic explanatory view showing another example of the image forming apparatus for performing the image forming method of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 electrostatic image carrier (photosensitive drum) 4 developing device 11 developer carrier (developing sleeve) 12 magnet roller 13, 14 developer transport screw 15 regulating blade 17 partition 18 replenishing toner 19 developer 19 a toner 19 b carrier 20 replenishing Port 21 Magnet roller 22 Transport sleeve 23 Magnetic particles 24 Laser beam 25 Transfer material (recording material) 26 Bias applying means 27 Transfer blade 28 Toner density detection sensor 61a Photosensitive drum 62a Primary charger 63a Developing device 64a Transfer blade 65a Replenishing toner 67a Laser beam 68 Transfer material carrier 69 Separation charger 70 Fixer 71 Fixing roller 72 Pressure roller 73 Web 75, 76 Heating means 79 Transfer belt cleaning device 80 Driving roller 81 Belt driven roller 2 belt discharger 83 registration rollers 85 toner concentration detecting sensor

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 9/08 375 G03G 9/10 352 9/107 9/08 321 15/06 101 331 9/10 331 362 (72) Inventor Yuji Mikuri 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Naotaka Ikeda 3-30-2, Shimomaruko 3-chome, Ota-ku, Tokyo Canon Inc. Person Masayoshi Kato 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 2H005 AA01 AA08 AA12 BA03 BA06 BA07 CA08 CA12 CA14 CA15 CA17 CA26 CA28 CB03 CB07 CB13 EA01 EA03 EA05 EA07 EA01 BA03A BA13 CA03 CA22

Claims (53)

[Claims] 1. A magnetic material-dispersed resin carrier in which the surface of a carrier core in which metal compound particles are dispersed in a binder resin is coated with a silicone resin, wherein the Si / Fe ratio of the carrier is 0.003 ≦ Si / Fe ≦ 0.03, and the Si /
Fe ratio reduction rate 0.5% ≦ Si / Fe reduction rate (%) ≦ 1
A magnetic material-dispersed resin carrier, wherein the carrier satisfies 5% and the light transmittance when the carrier is dispersed in an aqueous solution satisfies a transmittance T (%) ≧ 80%. 2. The carrier has a specific resistance of 1 × 10 ⁸ to 1
× 10 ¹⁵ (Ω · cm) and 1000 / 4π (kA /
m) is 20 to 100 (Am ² / k)
The magnetic material-dispersed resin carrier according to claim 1, wherein g) is satisfied. 3. The carrier core contains at least two or more kinds of metal compound particles, wherein the ratio of the metal compound to the binder resin is 80 to 99% by mass, and one of the metal compound particles is strong. A magnetic material, and the other is nonmagnetic metal compound particles having higher resistance than the ferromagnetic material, wherein the ratio of the ferromagnetic material to the total amount of the metal compound particles is 50 to 95% by mass. The magnetic material-dispersed resin carrier according to claim 1. 4. The particle diameter ratio between the number average particle diameter ra of the ferromagnetic material and the number average particle diameter rb of the nonmagnetic metal compound particles is 1 ≦
rb / ra ≦ 3, wherein rb / ra ≦ 3.
A magnetic material-dispersed resin carrier according to any one of the above. 5. The carrier core according to claim 1, wherein the carrier core contains magnetite as the ferromagnetic material, and contains hematite as at least one of the high-resistance metal compounds. Magnetic material-dispersed resin carrier. 6. The magnetic material-dispersed resin carrier according to claim 1, wherein the binder resin is a thermosetting resin and has a crosslinked structure. 7. The magnetic material-dispersed resin carrier according to claim 1, wherein the binder resin is a phenol resin. 8. The method according to claim 7, wherein the phenol resin is obtained in the presence of an ammonia catalyst.
3. The magnetic material-dispersed resin carrier according to item 1. 9. The surface of the metal compound particles is treated with a lipophilic treatment agent having at least one functional group selected from the group consisting of an epoxy group, an amino group and a mercapto group. The magnetic material-dispersed resin carrier according to claim 1. 10. The magnetic material-dispersed resin carrier according to claim 1, wherein the surface of the metal compound particles is treated with a lipophilic treatment agent having at least an epoxy group. . 11. The magnetic material-dispersed resin carrier according to claim 1, wherein the surface of the carrier core is coated with a silicone resin containing a coupling agent. 12. The magnetic material-dispersed resin carrier according to claim 1, wherein the surface of the carrier core is treated with a coupling agent and then coated with a silicone resin. . 13. The magnetic material-dispersed resin carrier according to claim 12, wherein the coupling agent is aminosilane. 14. A magnetic material-dispersed resin carrier in which a carrier core in which metal compound particles are dispersed in a binder resin is coated with a silicone resin, and a toner containing at least a binder resin and a colorant. In the component-based developer, the Si / Fe ratio of the carrier satisfies 0.003 ≦ Si / Fe ≦ 0.03, and the Si / Fe
The Fe ratio reduction rate satisfies 0.5% ≦ Si / Fe reduction rate (%) ≦ 15%, and the light transmittance when the carrier is dispersed in an aqueous solution is the transmittance T (%) ≧ 80%. Wherein the toner comprises at least a polyester resin as the binder resin. 15. The carrier has a specific resistance of 1 × 10 ⁸ or more.
1 × 10 ¹⁵ (Ω · cm) and 1000 / 4π (kA
/ M) is 20 to 100 (Am ² / k)
The two-component developer according to claim 14, wherein g) is satisfied. 16. The carrier core contains at least two or more kinds of metal compound particles, the ratio of the metal compound to the binder resin is 80 to 99% by mass, and one of the metal compound particles is strong. A magnetic material, and the other is nonmagnetic metal compound particles having higher resistance than the ferromagnetic material, wherein the ratio of the ferromagnetic material to the total amount of the metal compound particles is 50 to 95% by mass. The two-component developer according to claim 14 or 15, wherein 17. The particle diameter ratio between the number average particle diameter ra of the ferromagnetic material and the number average particle diameter rb of the nonmagnetic metal compound particles is 1
17. The two-component developer according to claim 14, wherein ≦ rb / ra ≦ 3. 18. The carrier core according to claim 14, wherein the carrier core contains magnetite as the ferromagnetic material, and contains hematite as at least one of the high-resistance metal compounds. Two-component developer. 19. The two-component developer according to claim 14, wherein the binder resin of the carrier core is a thermosetting resin and has a crosslinked structure. . 20. The two-component developer according to claim 14, wherein the binder resin of the carrier core is a phenol resin. 21. The magnetic material-dispersed resin carrier according to claim 20, wherein the phenol resin is obtained in the presence of an ammonia catalyst. 22. The surface of the metal compound particles is treated with a lipophilic treatment agent having at least one functional group selected from the group consisting of an epoxy group, an amino group and a mercapto group. The magnetic material-dispersed resin carrier according to any one of claims 14 to 21. 23. The magnetic material-dispersed resin carrier according to claim 14, wherein the surface of the metal compound particles is treated with a lipophilic treatment agent having at least an epoxy group. . 24. The magnetic material-dispersed resin carrier according to claim 14, wherein the surface of the carrier core is coated with a silicone resin containing a coupling agent. 25. The magnetic material-dispersed resin carrier according to claim 14, wherein the surface of the carrier core is treated with a coupling agent and then coated with a silicone resin. . 26. The magnetic material-dispersed resin carrier according to claim 25, wherein the coupling agent is aminosilane. 27. The toner according to claim 27, wherein the toner has at least one peak in a range of 280 to 350 nm when the absorbance of an extract obtained by extracting 0.1 mol / liter of sodium hydroxide is measured. Item 27. The two-component developer according to any one of Items 14 to 26. 28. The toner having a shape factor SF-1 of 10
15. The range of 0 to 120.
28. The two-component developer according to any one of the above items. 29. The two-component system according to claim 14, wherein the toner has a core / shell structure, and the core is formed of a material having a low softening point. Developer. 30. The two-component system according to claim 14, wherein the toner has a core / shell structure, and the core is formed of a material having a low softening point. Developer. 31. The toner according to claim 14, wherein the toner has, as an external additive, at least fine particles selected from the group consisting of silica fine particles, titanium oxide fine particles, and a mixture thereof. And a two-component developer. 32. An electrostatic image carrier is charged by charging means, the charged electrostatic image carrier is exposed to form an electrostatic image on the electrostatic image carrier, and the electrostatic image is developed by two-component development. A toner image is formed on an electrostatic image carrier by developing with a developing means having an agent, and the toner image on the electrostatic image carrier is transferred to a transfer material with or without an intermediate transfer member. An image forming method for fixing a toner image on a transfer material by a heating and pressurizing fixing means, wherein the two-component developer has at least a toner and a magnetic material-dispersed resin carrier; The magnetic material-dispersed resin carrier contains at least a binder resin and a colorant, and contains at least a polyester resin, and the carrier core surface in which metal compound particles are dispersed in the binder resin. Silico A magnetic material-dispersed resin carrier coated with a spine resin, wherein the Si / Fe ratio of the carrier satisfies 0.003 ≦ Si / Fe ≦ 0.03, and the Si / Fe ratio of the carrier after washing with toluene.
The Fe ratio reduction rate satisfies 0.5% ≦ Si / Fe reduction rate (%) ≦ 15%, and the light transmittance when the carrier is dispersed in an aqueous solution is the transmittance T (%) ≧ 80%. An image forming method characterized by satisfying the following. 33. The carrier has a specific resistance of 1 × 10 ⁸ or more.
1 × 10 ¹⁵ (Ω · cm) and 1000 / 4π (kA
/ M) is 20 to 100 (Am ² / k)
33. The image forming method according to claim 32, wherein g). 34. The carrier core contains at least two kinds of metal compound particles, the ratio of the metal compound to the binder resin is 80 to 99% by mass, and one of the metal compound particles is strong. A magnetic material, and the other is nonmagnetic metal compound particles having higher resistance than the ferromagnetic material, wherein the ratio of the ferromagnetic material to the total amount of the metal compound particles is 50 to 95% by mass. The image forming method according to claim 32 or 33, wherein 35. The particle diameter ratio of the number average particle diameter ra of the ferromagnetic material to the number average particle diameter rb of the nonmagnetic metal compound particles is 1
35. The image forming method according to claim 32, wherein ≦ rb / ra ≦ 3. 36. The carrier core according to claim 32, wherein the carrier core contains magnetite as the ferromagnetic material, and contains hematite as at least one of the high-resistance metal compounds. Image forming method. 37. The image forming method according to claim 32, wherein the binder resin of the carrier core is a thermosetting resin and has a crosslinked structure. 38. The image forming method according to claim 32, wherein the binder resin of the carrier core is a phenol resin. 39. The image forming method according to claim 38, wherein the phenol resin is obtained in the presence of an ammonia catalyst. 40. The surface of the metal compound particles is treated with a lipophilic treatment agent having at least one functional group selected from the group consisting of an epoxy group, an amino group and a mercapto group. The image forming method according to any one of claims 32 to 39. 41. The image forming method according to claim 32, wherein the surface of the metal compound particles is treated with a lipophilic treatment agent having at least an epoxy group. 42. The image forming method according to claim 32, wherein the surface of the carrier core is coated with a silicone resin containing a coupling agent. 43. The image forming method according to claim 32, wherein the surface of the carrier core is treated with a coupling agent and then coated with a silicone resin. 44. The image forming method according to claim 43, wherein the coupling agent is an aminosilane. 45. The toner according to claim 45, wherein the toner has at least one peak in the range of 280 to 350 nm when the absorbance of an extract obtained by extracting 0.1 mol / liter of sodium hydroxide is measured. Item 45. The image forming method according to any one of Items 32 to 44. 46. The toner having a shape factor SF-1 of 10
33. The range of 0 to 120.
45. The image forming method according to any one of the above items. 47. The image forming method according to claim 32, wherein the toner has a core / shell structure, and the core is formed of a material having a low softening point. . 48. The image forming method according to claim 32, wherein the toner has a core / shell structure, and the core is formed of a material having a low softening point. . 49. The toner according to claim 32, wherein the toner has at least fine particles selected from the group consisting of silica fine particles, titanium oxide fine particles and a mixture thereof as an external additive. An image forming method according to any one of the above. 50. The developing means has a developing sleeve enclosing a magnetic field generating means, and develops an electrostatic charge image with a two-component developer while applying an AC bias to the developing sleeve. The image forming method according to any one of the above. 51. The image forming method according to claim 50, wherein the waveform of the AC bias is continuous or discontinuous. 52. The image forming method according to claim 32, wherein the electrostatic charge image is a digital latent image, and the digital latent image is developed by a reversal developing method. 53. The image forming method according to claim 32, wherein the electrostatic image carrier is a photosensitive drum having an OPC photosensitive layer.