JP2002221821A - Toner for two-component developer, two-component developer, toner container, image forming apparatus and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide black toner for two-component developer which does not cause toner deposition of the background of an image and toner scattering or the like, especially, in the case of consecutively outputting many sheets of images having large image area, is excellent in fluidity, and hardly causes the occurrence of filming or the like, and further with which stable image quality is obtained over a long term even in the case of using small particle size toner, and to provide a two-component developer, a toner container, an image forming apparatus and an image forming method. SOLUTION: The black toner for two-component developer is used in the image forming apparatus (developing device) where the two-component developer consisting of toner and carrier is stirred by a stirring means, so that toner particles are triboelectrified, and the two-component developer including the electrified toner particles is held on a turnable nearly cylindrical developer carrier having a magnetic field generating means inside, whereby an electrostatic latent image formed on the image carrier is developed. The toner is constituted by incorporating a colorant made of at least metallic material in binding resin, and the saturation magnetization of the toner is 0.01 to 0 emu/g, and true specific gravity thereof is 1.35 to 1.60 g/cm3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a black toner for a two-component developer, a two-component developer, a toner container, an image forming apparatus and an image which are applied to an electrophotographic method, an electrostatic recording method, an electrostatic printing method and the like. It relates to a forming method.

[0002]

2. Description of the Related Art Conventionally, electrophotography has been disclosed in U.S. Pat. No. 2,297,691, Japanese Patent Publication No. 42-23910.
(U.S. Pat. No. 3,666,363) and Japanese Patent Publication No. 43-24748 (U.S. Pat.
No. 1,361), and the like, but generally, an electric latent image is formed on an image carrier such as a photosensitive member by various means, and then the obtained latent image is formed. Is developed using toner, and if necessary, the toner is transferred to a transfer material such as paper, and then fixed by heating, pressurizing, or solvent vapor while remaining on the image carrier without being transferred. The copied image is repeatedly obtained by cleaning the removed toner.

[0003] There are various developing methods for visualizing the electric latent image using toner, and they are roughly classified into a dry developing method and a wet developing method.

[0004] The dry development method is further divided into a method using a two-component developer composed of a toner and a carrier, and a method using a one-component developer composed only of a toner. Furthermore, it is divided into magnetic one-component developer using a magnetic material and non-magnetic one-component developer without using a magnetic material. The developing method used is dominant.

In the method using the two-component developer, the toner and the carrier are charged with different polarities by stirring and friction, and the charged toner is used to visualize an electrostatic image having the opposite polarity. Yes, depending on the type of toner and carrier, a magnetic brush method using an iron powder carrier (described in US Pat. No. 2,874,063) and a cascade method using a bead carrier (US Pat. No. 2,618,552) And the fur brush method are known. Further, as a toner applied to these various developing methods, a fine powder in which a colorant such as carbon black is dispersed in a binder resin made of a synthetic resin or a natural resin is used.

Here, if a continuous output of a large number of sheets is performed using a two-component developer, clear and good image quality can be obtained at the initial stage, but the supply of toner to the developer gradually stops, and the density decreases. Or the toner is mixed with the replenished toner in a state where the charge is insufficient, thereby making it easy to cause soiling, toner scattering, and the like. Tend to occur, such as image blurring and density unevenness, and this phenomenon is particularly remarkable at the time of continuous output of an image having a large image area. In addition, this phenomenon is caused by toner using carbon black as a colorant. , It tends to occur particularly.

Here, carbon black, which is generally used as a coloring agent, is a conductive substance and a high dielectric substance. Therefore, when dispersed and contained in toner, the conductivity of the toner itself increases, Resistance decreases. For this reason, background contamination, toner scattering, and the like are likely to occur, and an external electric field is more likely to be affected by charge injection and charge discharge. As a result, although the rising of the charge becomes good, the discharge of the charge is also quick, and the chargeability with time decreases,
The durability tends to decrease, and the transferability tends to deteriorate.

[0008] Further, carbon black forms secondary aggregates usually called agglomerates, and it is necessary to uniformly disperse these aggregates into primary particles. In practice, however, it is not possible to disperse them into primary particles. It is difficult, and usually only exists in the toner in a state of a primary aggregate called an aggregate or a state close thereto. For this reason, it is difficult to say that the dispersibility is sufficiently sufficient, whereby the charge amount tends to be non-uniform, and the background tends to be soiled and the toner is scattered.

On the other hand, a method has been proposed in which the surface of carbon black is subjected to an oxidation treatment to increase the resistance of the carbon black. Specifically, as a surface oxidation treatment method, for example, there is an oxidation treatment method using potassium permanganate as described in Japanese Patent Publication No. 5-31139. However, in this method, metal ions tend to remain as a counter ion of the carboxyl group on the carbon black surface, and the resistance of the carbon black decreases, and when used in a toner, it is not enough to improve the durability under high humidity. Effects cannot be obtained. In addition, Japanese Unexamined Patent Publication No.
Japanese Patent Publication No. 200158 discloses a surface oxidation treatment method using ozone. However, its purpose is to improve the dispersibility of carbon black by the interaction between carboxyl groups on the surface and polyester which is a binder resin for toner. Is 0.1 × 10 ⁻³ mol / g
Therefore, it is not sufficient in terms of improving the durability of the toner under high humidity.

On the other hand, in the one-component developer, a magnetic one-component developer containing a magnetic material is widely used instead of carbon black. %, The saturation magnetization of the toner is as high as about 10 to 50 emu / g, and the true specific gravity of the toner using carbon black containing no magnetic material is 1.2 to 1.3 g / cm. ^The characteristic is that it is as high as about 1.6 to 2.2 g / cm ³ , whereas the value is about ³ . However, when such a toner is used as a toner for a two-component developer, the magnetic binding force with respect to a carrier, a developer carrying member, and the like increases, so that the developing property is reduced, so that the image density is reduced. Is difficult to be detached from the surface of the carrier, so that the toner is easily fused to the surface of the carrier, and so-called carrier spent is liable to occur.

Further, a copying machine using electrophotography in recent years,
With the rapid spread of OA equipment such as printers and facsimile machines, demands for higher image quality and higher reproducibility than ever have been increasing. On the other hand, it is often practiced to improve the image quality by reducing the particle size of the toner.

Although reducing the particle size of the toner is effective for improving the image quality, the smaller the particle size of the toner, the more easily the dispersibility of each component of the toner is deteriorated. In addition, the distribution of the charge amount of the toner becomes uneven and wide, and the amount of the toner attached to the non-image portion on the photoreceptor increases.

Further, the smaller the particle size of the toner, the stronger the cohesiveness of the toner, thereby lowering the fluidity. Further, filming on the photoreceptor or the like tends to occur, and stable image quality can be obtained for a long period of time. This problem is particularly remarkable when carbon black is used as a colorant for the toner and the toner is used in an image forming apparatus that recycles the cleaned toner to the developing unit.

[0014]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems in the prior art. In particular, even in the continuous output of a large number of images having a large image area, background contamination and toner scattering occur. Black toner for two-component developer, two-component developer that can provide stable image quality over a long period of time even when a toner having a small particle diameter is used. An object of the present invention is to provide a developer, a toner container, an image forming apparatus, and an image forming method.

[0015]

SUMMARY OF THE INVENTION The object of the present invention is to provide (1) the present invention, wherein a toner component is frictionally charged by stirring a two-component developer composed of a toner and a carrier by a stirring means, and a magnetic field generating means is internally provided. An image forming apparatus (developing device) that holds a two-component developer containing charged toner particles on a rotatable substantially cylindrical developer carrier having a toner image and develops an electrostatic latent image formed on the image carrier In the black toner for a two-component developer used in (1), the toner comprises a binder resin containing at least a colorant made of a metal material, and the toner has a saturation magnetization of 0.01 to 10 emu / g, and Specific gravity is 1.
35 to 1.60 g / cm ³ , a black toner for a two-component developer ”, (2)“ the metallic material is made of Fe, Mn, T on the surface of hematite or maghematite.
The black for a two-component developer according to the above item (1), wherein one or more compounds selected from compounds of the respective elements i, Cu, Si and C are present. (3) The toner according to (1) or (2), wherein the metal material is a metal material that has been blackened by a surface treatment with a pigment and / or a dye. Black toner for component developer ", (4)" as the colorant,
(5) The black toner for a two-component developer according to any one of the above items (1) to (3), which contains 0.01 to 5% by weight of carbon black. (6) The black toner for a two-component developer according to any one of (1) to (4), wherein the toner has a saturation magnetization of 0.05 to 3 emu / g. The black for a two-component developer according to any one of the above items (1) to (5), wherein the true specific gravity of the toner is 1.40 to 1.55 g / cm ^3. toner ", (7)" dielectric loss tangent of the toner is 2.5 × ^{10 -} one of the paragraph (1), second (6) section, characterized in that a 3 to 7.5 × ^{10 -3} (8) The black toner for a two-component developer according to (1), (8) wherein the metal material has an average particle diameter of 0.01 to 0.8 μm. Serial No. (1), second (7) Black toner for two-component developer according to any one of claim ", (9)" with respect to 100 parts by weight of the binder resin content of the metallic material 10 to 2
The black toner for a two-component developer according to any one of the above items (1) to (8), wherein the binder resin is at least 5 parts by weight. Wherein the black toner for a two-component developer according to any one of the above items (1) to (9) is used, and (11) that the toner contains a release agent. Any one of the above items (1) to (10)
(12) The black toner for a two-component developer according to (12), wherein the release agent is at least one of carnauba wax, montan wax, and oxidized rice wax of a free fatty acid type. (13) The black toner for a two-component developer according to any one of the above items 1) to (11).
"The toner according to any one of the above items (1) to (12), wherein an additive is externally added, and at least silica and / or titania are used as the additive. Black toner for two-component developer ", (1
4) Achieved by "the black toner for a two-component developer as described in any one of the above items (1) to (13), wherein the weight average diameter of the toner is 2.5 to 10 [mu] m". Is done.

The object of the present invention is to provide a two-component developer using the black toner for a two-component developer and the carrier according to any one of the above items (1) to (14). (16) A two-component developer according to the above (15), wherein the carrier is coated with a coating material containing a silicone resin.

[0017] The above object is also achieved by (17) a "toner container filled with the black toner for a two-component developer according to any one of the above items (1) to (14)" of the present invention. Achieved.

The object of the present invention is also achieved in (18) an image forming apparatus for developing an electrostatic latent image formed on a latent image carrier according to the above (1) to (14). (19) An image forming apparatus using the black toner for a two-component developer according to any one of (1), (2) a step of forming an electrostatic latent image on a latent image carrier, and an obtained electrostatic image. Developing the latent image, transferring the developed toner image to a transfer material, cleaning the toner remaining on the latent image carrier,
An image forming apparatus having at least a step of recycling the cleaned toner to a developing unit, wherein the black toner for a two-component developer according to any one of the above items (1) to (14) is used. Characteristic image forming apparatus ", (20)" a step of forming an electrostatic latent image on a latent image carrier, a step of developing the obtained electrostatic latent image, and transferring the obtained toner image to a transfer material An image forming apparatus having at least a step of cleaning the toner remaining on the latent image carrier and a step of recycling the cleaned toner to a developing unit, wherein a magnetic field generating mechanism is provided in the recycling step. (21) "a step of forming an electrostatic latent image on a latent image carrier, and a step of developing the obtained electrostatic latent image." Toner image A classifying mechanism in the recycling step in an image forming apparatus having at least a step of transferring the toner to the transfer material, a step of cleaning the toner remaining on the latent image carrier, and a step of recycling the cleaned toner to the developing unit. The image forming apparatus according to the above mode (19) or (20). "

The object of the present invention is also achieved in (22) an image forming method for developing an electrostatic latent image formed on a latent image carrier according to the above (1) to (14). (23) An image forming method characterized by using the black toner for a two-component developer according to any one of (1) and (2), wherein the electrostatic latent image formed on the latent image carrier is developed and developed. In the image forming method, after the toner image is transferred to the transfer material, the toner remaining on the latent image carrier is cleaned, and the cleaned toner is recycled to a developing unit.
Item, wherein the black toner for a two-component developer is used in any one of the items (1) to (14).
(24) "After developing the electrostatic latent image formed on the latent image carrier and transferring the developed toner image to a transfer material, the toner remaining on the latent image carrier is cleaned and cleaned. The image forming method for recycling the cleaned toner to the developing section, wherein the magnetic field generating means is used for recycling the cleaned toner to the developing section. (2
5) “After developing the electrostatic latent image formed on the latent image carrier and transferring the developed toner image to a transfer material, the toner remaining on the latent image carrier is cleaned and cleaned. The image according to (23) or (24), wherein in the image forming method for recycling the toner to the developing unit, a classification unit is used for recycling the cleaned toner to the developing unit. Forming method "
Is achieved by

According to the present invention, there is provided a rotatable substantially cylindrical developer carrier having a magnetic field generating means therein by frictionally charging toner particles by stirring a two-component developer comprising toner and carrier by stirring means. A two-component developer containing charged toner particles is held thereon, and a two-component developer black toner used in an image forming apparatus that develops an electrostatic latent image formed on an image carrier is described below. A binder resin containing at least a colorant made of a metal material, wherein the toner has a saturation magnetization of 0.01 to 10 emu / g and a true specific gravity of 1.35 to 1.60 g / cm ^3. And a black toner for a two-component developer.

As a result of intensive studies, the present inventors frictionally charge toner particles by agitating a two-component developer composed of toner and carrier by agitating means, and are rotatable having a magnetic field generating means inside. On a substantially cylindrical developer carrier, holding a two-component developer containing charged toner particles,
In a black toner for a two-component developer used in an image forming apparatus for developing an electrostatic latent image formed on an image carrier, the toner comprises a binder resin containing at least a colorant made of a metal material. Further, the saturation magnetization of the toner is 0.0
1-10 emu / g, true specific gravity 1.35-1.60 g /
By satisfying the relationship of cm ³ , especially in continuous output of a large number of images having a large image area, background smear and toner scattering do not occur, the fluidity is excellent, the occurrence of filming and the like is small, and furthermore, It has been found that even when a toner having a small particle diameter is used, stable image quality can be obtained over a long period of time.

In particular, according to the present invention, a sufficient blackness can be obtained even in a toner containing no carbon black or having a carbon black content of 5% by weight or less, and further defines a saturation magnetization and a true specific gravity. By solving the various problems described above, the present inventors, in particular, using a metal material that is blackened by a surface treatment with a pigment and / or dye or itself is a black metal material,
Further, it has been found that a toner having a specific saturation magnetization and a true specific gravity is an effective solution to the above problem. Here, such a weakly magnetic toner close to non-magnetic and
Toners having a true specific gravity close to that of a conventional toner using carbon black have not existed so far.

Hereinafter, the present invention will be described in detail. As described above, the black toner for a two-component developer of the present invention frictionally charges the toner particles by stirring the two-component developer composed of the toner and the carrier by the stirring means, and has a magnetic field generating means inside. On a movable substantially cylindrical developer carrier,
In a black toner for a two-component developer used in an image forming apparatus that holds a two-component developer containing charged toner particles and develops an electrostatic latent image formed on an image carrier, the toner is bound. The resin contains at least a colorant made of a metal material, and the toner has a saturation magnetization of 0.01 to 10 e.
mu / g and a true specific gravity of 1.35 to 1.60 g / cm ³ .

In the conventional toner, in order to exhibit a black color,
Carbon black is mainly used as a coloring agent.
Since this carbon black is a conductive substance and a high dielectric substance, when dispersed and contained in the toner, the conductivity of the toner itself increases and the resistance decreases. For this reason, background contamination, toner scattering, and the like are likely to occur, and an external electric field is more likely to be affected by charge injection and charge discharge. As a result, although the rising of the charge becomes good, the charge is released quickly, the chargeability with the lapse of time is reduced, the durability tends to be reduced, and the transferability tends to be poor.

Further, carbon black forms secondary aggregates usually called agglomerates, and it is necessary to uniformly disperse the aggregates into the primary particles. In practice, however, it is not possible to disperse the aggregates into the primary particles. It is difficult, and usually only exists in the toner in a state of a primary aggregate called an aggregate or a state close thereto. For this reason, it is difficult to say that the dispersibility is sufficiently sufficient, whereby the charge amount tends to be non-uniform, and the background tends to be soiled and the toner is scattered.

On the other hand, the toner particles are frictionally charged by stirring the two-component developer composed of the toner and the carrier by the stirring means, and the rotatable substantially cylindrical developer carrier having a magnetic field generating means therein is provided. A two-component developer containing charged toner particles on a body, and a two-component developer black toner used in an image forming apparatus for developing an electrostatic latent image formed on an image carrier. Comprises a binder resin containing at least a colorant made of a metal material, and further has a saturation magnetization of 0.01 to 10 emu /
g, the true specific gravity of 1.35 to 1.60 g / cm ³ satisfies the relationship, does not cause background contamination and toner scattering, has excellent fluidity, has little occurrence of filming, and is stable over a long period of time. It is possible to obtain high quality, and it is particularly effective for continuous output of a large number of images having a large image area. The effect can be obtained.

This is because a magnetic toner containing a magnetic material or the like has a higher saturation magnetization and a higher magnetic binding force on a developer carrying member than a non-magnetic toner using carbon black or the like. Developability tends to decrease. On the other hand, the saturation magnetization of the toner is 0.01 to 10 emu / g,
Particularly preferably, when the content is 0.05 to 3 emu / g, a decrease in developability due to an increase in magnetic binding force can be prevented. Further, since the toner has an appropriate magnetism, the toner is Due to the restraint, the occurrence of toner adhesion or toner scattering to the non-image area can be greatly reduced. At this time, the true specific gravity of the toner is 1.35 to 1.60 g / cm ³ , particularly preferably 1.35 g / cm ³ .
It is also important that it is slightly higher than 40 to 1.55 g / cm ³ as compared with a toner using conventional carbon black.
This makes it easier for the toner to flow, so that good chargeability can be obtained. Further, since the difference in specific gravity between the toner and the carrier of the two-component developer is reduced, uniform mixing is improved. Even during replenishment, the toner is uniformly mixed with the carrier in a short period of time, so that it is possible to greatly reduce the occurrence of background contamination and toner scattering when replenishing the toner. It is possible to obtain a high effect even at the time of continuous output of a large image, and in addition, a high effect can be obtained even when a toner having a small particle diameter whose characteristics are more likely to be deteriorated in recycling is used. Therefore, it is considered that a high-quality image can be obtained. Furthermore, the true specific gravity is 1.35.
Since the true specific gravity of a toner having a density of up to 1.60 g / cm ³ is higher than that of a toner using conventional carbon black, classification accuracy during production is also improved, so that high productivity can be obtained.

In the above-described image forming apparatus, by providing a toner selecting mechanism by a magnetic field generating means in the recycle section, the transfer paper fibers mixed in the collected toner and the filler such as talc, kaolin, calcium carbonate, etc. And
Suspended matter in the air, furthermore, low-magnetization toner such as fine-powder toner and low-coloration toner in which the coloring agent is not sufficiently dispersed can be prevented from being re-mixed into the developing section. In addition to the reduction in image density, the increase in background contamination and toner scattering, and the occurrence of filming, etc., the occurrence of carrier spent due to fine powder toner, transfer unevenness, white spots, etc. It is possible to suppress the occurrence of defects and the like. Further, in the above-described image forming apparatus, by providing a toner sorting mechanism by a classifying means in the recycling section, fibers of transfer paper mixed in the collected toner, filler such as talc, kaolin, calcium carbonate, etc. Suspended matter, further, the toner having deteriorated properties such as agglomerated toner can be prevented from being re-mixed into the developing section, whereby the image density decreases over time, and background contamination and toner scattering increase, In addition to significantly suppressing the occurrence of filming and the like, it is also possible to further suppress the occurrence of image defects such as transfer unevenness and white spots.

Here, the saturation magnetization of the toner is 0.01 em
If the ratio is less than u / g, the magnetic transport force is weak, which tends to cause toner scattering and uneven development. Further, the polishing effect on the surface of the photoreceptor is insufficient, so that filming is likely to occur. In particular, when used in an image forming apparatus using a magnetic field generating means in the recycling section, it is difficult to recycle the collected toner.

On the other hand, when the saturation magnetization exceeds 10 emu / g, the magnetic binding force on the carrier such as the carrier and the developing sleeve increases, so that the developability decreases.
As a result, the image density is reduced, and the toner is less likely to be detached from the carrier surface, so that the toner is easily fused to the carrier surface, so-called carrier spent is liable to occur, and the fixability is also likely to deteriorate. .

The true specific gravity of the toner is 1.35 g / cm.
^When the ratio is less than ³ , the toner becomes difficult to flow and the chargeability is reduced. When a large amount of an additive is contained for the purpose of compensating for the decrease, the photosensitive member cleaning failure such as chattering and turning over of the blade and the toner are separated from the toner. Filming of the photoreceptor or the like by the additive is apt to occur, and various problems occur such that the durability of the cleaning blade or the photoreceptor is reduced, and the fixing property is easily deteriorated. Further, when used as a two-component developer, the difference in specific gravity between the toner and the carrier is large, so that the uniform mixing property of the toner and the carrier is reduced. Background dirt and toner scattering are likely to occur.Furthermore, when used in an image forming apparatus using a classifying and sorting means utilizing a specific gravity difference in the recycling section, fibers such as transfer paper having low specific gravity and fillers are used. Since the difference in specific gravity from the attached matter becomes small, the classification accuracy of the collected toner tends to decrease.

On the other hand, the true specific gravity of the toner is 1.60 g / cm
If it exceeds ³ , the number of toner particles per unit weight decreases, the charge amount per particle increases, and furthermore, the transportability of the developer to the developer carrier decreases, so that
The developing property tends to decrease, and the required toner weight per the same amount of adhesion also increases, which undesirably increases the toner consumption and increases the cost.

Here, the true specific gravity of the toner is measured by an air comparison specific gravity meter 930 (manufactured by Beckman Japan KK).
This was performed using

As the metal material used in the toner of the present invention, one or two or more compounds selected from compounds of Mn, Ti, Cu, Si and C are formed on the surface of hematite or maghemite. Preferably, the compound is present. Further, a metal material blackened by a surface treatment with a pigment and / or a dye can also be used. Here, as a material that can be used for the surface treatment of the metal material, for example, dyes and pigments such as carbon black, iron black, aniline black, graphite, and fullerene, and black by using a plurality of dyes and pigments or compounds in combination. Dyes and pigments, compounds, and the like that appear can also be used. In addition, the above metal materials include lead, tin, aluminum, antimony, sodium, magnesium, phosphorus, sulfur, potassium, calcium, chromium, cobalt, selenium, beryllium, bismuth, cadmium, nickel, tungsten, vanadium, zinc, chlorine, etc. Can be used.

The metal material may contain 0.01% of a conventionally known black colorant such as an azine dye such as carbon black, oil furnace black, channel black, lamp black, acetylene black or aniline black, or a metal salt azo dye. ~ 5% by weight, preferably 0.01 ~
It is also possible to use them together in the range of 3% by weight, or to use a blue colorant such as copper phthalocyanine blue as a complementary color. However, the addition of a small amount of 0.01 to 5% by weight is preferable in terms of color tone because the blackness is further increased, but is preferably not contained.
If the content is more than 5% by weight, the electric resistance of the toner is lowered, and the dispersibility is insufficient, so that background fouling and toner scattering are liable to occur, and the magnetic transport force is obtained. As a result, uneven development is likely to occur, and the effect of polishing the surface of the photoreceptor becomes insufficient, so that filming is likely to occur.

As described above, since the metal material can be made black by making the metal material have the above configuration,
It can have a function as a black colorant instead of carbon black or the like, and further, by using such a material, it becomes possible to prevent filming or the like due to a polishing effect on a photoreceptor or the like.

Here, these metal materials have an average particle diameter of 0.01 to 0.8 μm, preferably 0.02 to 0.5 μm.
When the average particle size is less than 0.01 μm, the dispersibility in the binder resin is deteriorated, and the fixability is also deteriorated. When the average particle size exceeds 0.8 μm, a sufficient degree of coloring cannot be obtained, and the dispersibility in the binder resin is deteriorated.

The content of the metal material is 100
The amount is preferably 5 to 50 parts by weight, particularly preferably 10 to 25 parts by weight based on parts by weight.

When the content of the metal material is less than 5 parts by weight, the coloring power of the toner is reduced, and the polishing effect on the surface of the photoreceptor becomes insufficient. When the toner is used in an image forming apparatus using a magnetic field generating means in the recycling section, the saturation magnetization of the toner is reduced, so that it is difficult to recycle the collected toner. If the amount is more than 50 parts by weight, the metal material is agglomerated and the dispersibility is deteriorated, and the developability is deteriorated due to a decrease in chargeability.
Further, since the content of the binder resin in the toner is relatively reduced, the fixing strength of the toner, which is the toner performance derived from the binder resin, to the paper is reduced, and the toner is peeled off from the image after fixing. Deterioration and blurring of the image quality such as bleeding are likely to occur.

Although the magnetic properties of these metallic materials are not particularly defined, the saturation magnetization is 0.05 to 60 em.
u / g, particularly preferably in the range of
0.1 to 40 emu / g.

Here, when the saturation magnetization is higher than 60 emu / g, the metallic materials tend to agglomerate with each other due to the magnetic force, and the saturation magnetization of the toner also increases. Since the magnetic binding force against the body and the like is increased, the developability is reduced, and therefore, the image density is reduced. Further, since the toner is hardly detached from the carrier surface, the toner is easily fused to the carrier surface. And the fixability tends to deteriorate.

The toner of the present invention has a dielectric loss tangent of 2.
It is preferably from 5 × 10 ^{−3 to} 7.5 × 10 ⁻³ , and particularly preferably from 2.5 × 10 ^{−3 to} 5.0 × 10 ^−3.
−3 . The dielectric loss tangent of the toner is from 2.5 × 10 ⁻³ to
By setting the range of 7.5 × 10 ⁻³ , the dispersion state of the colorant and the like in the toner becomes uniform and finely dispersed, whereby the charge amount distribution of the toner is within a certain narrow range. And excellent charge retention and stability can be obtained.

Here, the dielectric loss tangent of the toner is 7.5 × 10
If it exceeds ^-3 , the conductivity becomes high, which results in poor charging and a tendency to increase background contamination, toner scattering, and the like. In addition, since the dispersibility of the colorant and the like in the toner is also deteriorated, the charge amount distribution of the toner becomes non-uniform, and a high-quality image cannot be stably obtained. Further, when the dielectric loss tangent of the toner is less than 2.5 × 10 ⁻³ , the resistance increases, so that the charge amount increases and the image density tends to decrease.

Here, the measurement of the dielectric loss tangent of the toner was performed as follows. First, a toner molded into a pellet having a thickness of about 2 mm is supplied to a solid electrode (SE-SED manufactured by Ando Electric Co., Ltd.).
70)), and the phase shift when an alternating current of 1 kHz is applied between the electrodes is measured by a dielectric loss measuring device (TR-10C manufactured by Ando Electric Co., Ltd.), whereby the toner is removed. The dielectric loss tangent was calculated.

The toner of the present invention has a residual magnetization of 4e.
mu / g or less, particularly preferably 1 / mu / g or less.
emu / g or less. Here, the residual magnetization of the toner is 4
If it exceeds emu / g, dispersibility and durability tend to be poor.

The toner of the present invention has a coercive force of 50O.
e or less. Here, when the coercive force of the toner exceeds 50 Oe, the cohesiveness between the toners becomes strong, and the fluidity of the toner may decrease.

Here, the magnetic properties of the colorant and the toner were measured by using a magnetometer BHU-60 manufactured by Riken Denshi Co., Ltd.
The saturation magnetization, remanence magnetization, and coercive force were determined from the hysteresis curve when the magnetic field was swept up to 10 kOe on the toner filled in the cell having an inner diameter of 7 mm and a height of 10 mm.

As the binder resin used in the toner of the present invention, conventionally known binder resins can be used. For example, styrene such as polystyrene, poly-p-styrene and polyvinyltoluene and a homopolymer of a substituted product thereof, styrene-p
-Chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-
Methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-methacrylic acid copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-methacrylic acid Butyl copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, Styrene-based copolymers such as styrene-isopropyl copolymer, styrene-maleic acid ester copolymer, etc., polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polyester, polyurethane, epoxy resin, polyvinyl Butyral, Riakuriru acid resin, rosin, modified rosin, terpene resins, phenol resins, aliphatic or aliphatic hydrocarbon resins, aromatic petroleum resins, and the like can be used alone or in combination.

Particularly, as the binder resin used in the toner of the present invention, a polyester resin is particularly preferred from the viewpoint of low-temperature fixability and the like. Polyester resin is a resin having sharp melt properties and strong cohesion of the resin even at a low molecular weight, so that it is easy to achieve both low-temperature fixability and offset resistance. When using not only the polyester resin but also other resins, it is preferable that 80% by weight or more of the binder resin is the polyester resin so as not to impair the good properties of the polyester resin. Among them, the polyester resin used in the present invention includes (a) at least one selected from divalent carboxylic acids and lower alkyl esters and acid anhydrides thereof, and (b) diols represented by the following general formula (I). component,

[0050]

Embedded image (In the formula, R ¹ and R ² may be the same or different and each is an alkylene group having 2 to 4 carbon atoms, x and y are positive integers, and the sum is 2 to 16.) (C) a polyester resin obtained by reacting a trivalent or higher polycarboxylic acid, a lower alkyl ester and an acid anhydride thereof, and at least one selected from trivalent or higher polyhydric alcohols; Is preferred.

Examples of the divalent carboxylic acid (a) and its lower alkyl esters and acid anhydrides include terephthalic acid, isophthalic acid, sebacic acid, isodecylsuccinic acid, maleic acid, fumaric acid and Monomethyl, monoethyl, dimethyl and diethyl esters,
And phthalic anhydride and maleic anhydride, and terephthalic acid, isophthalic acid and dimethyl esters thereof are particularly preferred in terms of blocking resistance and cost. These divalent carboxylic acids and their lower alkyl esters and acid anhydrides greatly affect the fixing property and blocking resistance of the toner. That is, although depending on the degree of condensation, the use of a large amount of aromatic terephthalic acid, isophthalic acid or the like improves the blocking resistance but decreases the fixing property. Conversely, when sebacic acid, isodecylsuccinic acid, maleic acid, fumaric acid, etc. are used in a large amount, the fixing property is improved, but the blocking resistance is lowered. Therefore, these divalent carboxylic acids are appropriately selected according to other monomer compositions, ratios, and degrees of condensation,
Used alone or in combination.

An example of the diol component (b) represented by the general formula (I) is polyoxypropylene-
(N) -polyoxyethylene- (n ')-2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene- (n) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene -(N) -2,2-
Examples thereof include bis (4-hydroxyphenyl) propane, and particularly, polyoxypropylene- (n) -2,2-bis (4-hydroxyphenyl) propane and 2.1 ≦ n ≦ 2.5. Polyoxyethylene- (n) -2,2-bis (4-hydroxyphenyl) propane in which 0 ≦ n ≦ 2.5 is preferred. Such a diol component has an advantage that the glass transition temperature is improved and the reaction is easily controlled.

As the diol component, aliphatic diols such as ethylene glycol, diethylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol and propylene glycol are used. Is also possible.

However, these aliphatic diols are softer than the diols represented by the above general formula (I) and tend to have a lower glass transition temperature. Adhesiveness between toners increases, and additives and the like are easily buried, so that aggregation tends to occur.

Examples of the (c) tri- or higher-valent polycarboxylic acid and its lower alkyl ester and acid anhydride include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 1,3,5- Benzenetricarboxylic acid, 1,
2,4-cyclohexanetricarboxylic acid, 2,5,7-
Naphthrenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid,
1,2,5-hexatricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, tetra (methylenecarboxy) methane, 1,2,2
7,8-octanetetracarboxylic acid, empol trimer acid and their monomethyl, monoethyl, dimethyl and diethyl esters.

Examples of the trihydric or higher polyhydric alcohol (c) include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, and tripentane. Erythritol, sucrose, 1,2,4-butanetriol, 1,
2,5-pentatriol, glycerol, diglycerol, 2-methylpropanetriol, 2-methyl-
1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene and the like can be mentioned.

The proportion of the trivalent or higher polyvalent monomer is suitably about 1 to 30 mol% of the whole monomer composition. When the amount is less than 1 mol%, the offset resistance of the toner decreases, and the durability tends to deteriorate. On the other hand, if it exceeds 30 mol%, the fixability of the toner tends to deteriorate.

Of these trivalent or higher polyvalent monomers, benzenetricarboxylic acids such as benzenetricarboxylic acid and anhydrides or esters of these acids are particularly preferred. That is, by using benzenetricarboxylic acids, it is possible to achieve both fixability and offset resistance. Further, when used in an image forming apparatus that recycles toner collected from an image carrier such as a photoreceptor, an intermediate transfer member, and a transfer belt to a developing unit, the rubbing during transfer to the cleaning unit and the developing unit is performed. Since the destruction of the toner particles due to mechanical external force such as heat and agitation is unlikely to occur, the change in the particle size of the toner over time is small, and a high effect on durability and the like can be obtained.

The glass transition temperature (Tg) of these binder resins is preferably 55 ° C. or higher, particularly preferably 60 ° C. or higher, from the viewpoint of heat resistance and storage stability.

The method for producing these binder resins is not particularly limited, and any of bulk polymerization, solution polymerization, emulsion polymerization, suspension polymerization and the like can be used.

A releasing agent, a charge controlling agent, an additive and the like can be added to the toner of the present invention, if necessary.

As the release agent used in the toner of the present invention, conventionally known release agents can be used. In particular, a free fatty acid type carnauba wax, montan wax and rice oxide wax can be used alone or in combination. preferable. Here, the carnauba wax is preferably a microcrystalline wax, particularly preferably a wax having an acid value of 5 or less and a particle diameter of 1 μm or less when dispersed in a binder resin. The montan wax generally refers to a montan wax refined from minerals, and is preferably microcrystalline and has an acid value of 5 to 14 like carnauba wax. The oxidized rice wax is obtained by oxidizing rice bran wax with air, and preferably has an acid value of 10 to 30. As other release agents, any conventionally known release agents such as solid silicone varnish, higher fatty acid higher alcohol, montan ester wax, and low molecular weight polypropylene wax can be mixed and used.

Further, the melting point of the release agent at this time is 75 to
Particularly preferred is 125 ° C. By setting the melting point to 75 ° C. or higher, a toner having excellent durability can be obtained, and by setting the melting point to 125 ° C. or lower, the toner is quickly melted at the time of fixing, and a reliable releasing effect can be exhibited.

The content of these release agents depends on the binder resin 10
The amount is preferably from 1 to 20 parts by weight, particularly preferably from 2 to 10 parts by weight, per 0 parts by weight. When the amount is less than 1 part by weight, the effect of preventing offset is insufficient, and when the amount is more than 20 parts by weight, transferability, durability and the like are reduced.

Here, the melting point of the release agent was measured as follows. That is, a melting point analyzer (Rigaku, manufactured by Rigaku Corporation)
Thermoflex TG8110) was used at a heating rate of 10 ° C./min, and the main peak of the endothermic curve was defined as the melting point.

As the charge control agent used in the toner of the present invention, conventionally known charge control agents can be used. First, nigrosine and its modified product, tributylbenzyl ammonium-1 -Hydroxy-4-naphthosulfonate, quaternary ammonium salts such as tetrabutylammonium tetrafluoroborate, diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide, dibutyltin borate, dioctyltin borate, dicyclohexyltin borate And the like. In addition, as a device that controls the toner to be negatively charged, azo metal complexes and salts such as azo iron complexes, salicylic acid metal complexes and salts, organic boron salts, calixarene compounds and the like can be mentioned. These can be used alone or in combination of two or more.

The content of these charge control agents is as follows:
It is preferably 0.1 to 10 parts by weight, particularly preferably 1 to 5 parts by weight, per 100 parts by weight.

As the additives used in the toner of the present invention, conventionally known additives can be used.
i, Ti, Al, Mg, Ca, Sr, Ba, In, G
a, Ni, Mn, W, Fe, Co, Zn, Cr, Mo,
Examples thereof include oxides such as Cu, Ag, V, and Zr and composite oxides. In particular, silica and titania, which are oxides of Si and Ti, are more preferably used in terms of fluidity improvement, charge stabilization, recyclability, and the like. Used.

The amount of the additive is preferably 0.1 to 5 parts by weight, particularly preferably 0.5 to 2 parts by weight, based on 100 parts by weight of the base particles.

If the amount of the additive is less than 0.1 part by weight, sufficient fluidity cannot be obtained because the fluidity of the toner decreases, and transferability and heat-resistant storage stability become insufficient. It is also likely to cause soiling and toner scattering. Also, 5
When the amount is more than the weight part, the fluidity is improved, but chatter,
Poor cleaning of the photoreceptor, such as turning over of the blade, and filming on the photoreceptor due to the additives released from the toner are likely to occur, and the durability of the cleaning blade, the photoreceptor, etc. is reduced, and the fixing property is also deteriorated.

Here, there are various methods for measuring the content of the additive, but it is generally determined by X-ray fluorescence analysis. That is, for a toner having a known additive content,
A calibration curve is prepared by X-ray fluorescence analysis, and the content of the additive can be determined using the calibration curve.

Further, it is preferable that the additives used in the toner of the present invention have been subjected to a surface treatment, if necessary, for the purpose of hydrophobicity, improvement of fluidity, control of chargeability, and the like.

The treating agent used for the surface treatment is preferably an organic silane compound, for example, alkylchlorosilanes such as methyltrichlorosilane, octyltrichlorosilane, dimethyldichlorosilane, dimethyldimethoxysilane, octyltrimethoxysilane. Such as alkylmethoxysilanes, hexamethyldisilazane,
And silicone oil.

As a treatment method, a method in which an additive is immersed in a solution containing an organic silane compound and dried is used.
Although there is a method of spraying and drying a solution containing an organic silane compound as an additive, any method can be suitably used in the present invention.

Further, the additive used in the toner of the present invention has an average primary particle diameter of 0.00 from the viewpoint of imparting fluidity.
It is preferably from 2 to 0.1 μm, particularly preferably from 0.005 to 0.05 μm.

Additives having an average primary particle diameter of less than 0.002 μm are liable to be buried in the surface of the base particles, so that aggregation tends to occur and sufficient fluidity cannot be obtained. Further, filming on the photoreceptor is also likely to occur, and these tendencies are particularly remarkable under high temperature and high humidity. In addition, when the average primary particle size is smaller than 0.002 μm, the additives are liable to agglomerate inevitably, so that it is difficult to obtain sufficient fluidity.

In particular, when the toner is used in an image forming apparatus that recycles toner collected from an image carrier such as a photoreceptor, an intermediate transfer member, and a transfer belt to a developing unit, the fluidity deteriorates. The transferability during transfer to the cleaning unit or the developing unit is reduced, and the transfer unit receives a mechanical external force such as rubbing or stirring during transfer to the cleaning unit or the developing unit. Therefore, if these toners are re-mixed into the developing unit by recycling, transfer unevenness and white spots, and background contamination and in-machine contamination due to the toner are likely to be further deteriorated over time. The properties and the like are also likely to decrease.

Additives having an average primary particle size of more than 0.1 μm decrease the fluidity of the toner, failing to obtain sufficient chargeability, and are liable to cause background contamination and toner scattering. Additives having an average primary particle diameter of more than 0.1 μm are apt to damage the surface of the photoreceptor and cause filming or the like. The particle size of the additive can be determined by measuring with a transmission electron microscope.

The toner of the present invention may further contain other additives in addition to the above additives. Examples of such additives include, for example, polytetrafluoroethylene-based fluororesin as a lubricant, zinc stearate and polyvinylidene fluoride, and cerium oxide as an abrasive,
Silicon carbide, strontium titanate, and the like, and zinc oxide, antimony oxide, tin oxide, and the like as the conductivity-imparting material, respectively.

The toner of the present invention is generally produced as follows. The above-mentioned binder resin, colorant, and if necessary, a charge control agent, a release agent, and other additives are sufficiently mixed by a mixer such as a Henschel mixer. A batch type twin roll, a Banbury mixer or a continuous type twin screw extruder such as a KTK type twin screw extruder manufactured by Kobe Steel, a TEM type twin screw extruder manufactured by Toshiba Machine Co., a twin screw extruder manufactured by KCK, PCM type twin screw extruder manufactured by Ikegai Iron Works,
The constituent materials are kneaded well using a KEX twin screw extruder manufactured by Kurimoto Tekkosho Co., Ltd., or a continuous single screw kneader such as a co-kneader manufactured by Buss. After cooling the kneaded material, coarsely pulverized using a hammer mill or the like,
Further, the particles are finely pulverized by a fine pulverizer or a mechanical pulverizer using a jet stream, and classified to a predetermined particle size by a classifier using a swirling stream or a classifier using the Coanda effect to obtain base particles.

Further, as other production methods, a polymerization method, a capsule method and the like can be used. The outline of these production methods is described below.

(Polymerization Method Toner) A polymerizable monomer, and if necessary, a polymerization initiator, a colorant and the like are granulated in an aqueous dispersion medium. The granulated monomer composition particles are classified into an appropriate particle size. The monomer composition particles having a specified internal particle diameter obtained by the classification are polymerized. After a suitable treatment to remove the dispersant, the polymerization product obtained above is filtered, washed with water and dried to obtain base particles.

(Capsule Toner) A resin, a colorant and the like, if necessary, are kneaded with a kneader or the like to obtain a molten toner core material. The toner core is placed in water and stirred vigorously to produce a fine particle core. The above core material fine particles are put into a shell material solution, and a poor solvent is dropped with stirring, and the core material is encapsulated by covering the surface of the core material with the shell material. The capsules obtained above are filtered and then dried to obtain base particles.

Then, the base particles and additives such as inorganic oxides are sufficiently mixed by a mixer such as a Henschel mixer (manufactured by Mitsui Miike), a mechanofusion system (manufactured by Hosokawa Micron), a mechanomill (manufactured by Okada Seiko), or the like. And, if necessary, pass through a sieve having an opening of about 150 μm or less,
Aggregates and coarse particles are removed.

Here, the toner of the present invention has a stirring blade tip peripheral speed of 15 to 35 m when mixing the base particles and the additives.
/ Sec. It is preferred that The peripheral speed of the stirring blade tip is 15 m / sec. If the temperature is lower, sufficient mixing is not performed, so that the additives are not uniformly mixed, and the released additives adhere to the image carrier such as a photoconductor, a developing roller, a carrier, and the like, and filming is performed. And the like, and also tends to cause background contamination and a decrease in developability due to insufficient charging of the toner.

On the contrary, the peripheral speed of the tip of the stirring blade is 35 m / sec.
c. If it is higher, the additive strongly adheres to the base particles and is easily embedded in the surface of the base particles, so that aggregation is likely to occur and sufficient fluidity cannot be obtained. In addition, the toner may be melted due to heat generated during mixing.
In the case of a color toner, a low-softening binder resin having a large amount of low molecular weight components is generally used, so that the tendency is more remarkable.

In particular, when the toner is used in an image forming apparatus for recycling toner collected from an image carrier such as a photoreceptor, an intermediate transfer member, and a transfer belt to a developing unit, the fluidity deteriorates. The transferability during transfer to the cleaning unit or the developing unit is reduced, and the transfer unit receives a mechanical external force such as rubbing or stirring during transfer to the cleaning unit or the developing unit. Therefore, if these toners are re-mixed into the developing unit by recycling, transfer unevenness and white spots, and further, the soiling of the background and in-machine contamination due to the toner are likely to be further deteriorated over time. Developability also tends to decrease.

The particle diameter of the toner of the present invention is preferably 2.5 to 10 μm, more preferably 4 to 8 μm in terms of weight average diameter.

In particular, by incorporating the metal material having a high hardness and a high specific gravity used in the present invention into the toner, in the pulverizing step at the time of producing the toner, due to the difference in the hardness with the binder resin, the stress concentration site is reduced. Are formed at the interface between the binder resin and the metal material, so that they are easily crushed, and it is possible to cope with a reduction in the particle size of the toner. Further, according to the configuration of the present invention, even with a toner having a small particle diameter, a high effect can be obtained with respect to background contamination, toner scattering, filming, and the like.

In the case where the particle diameter is smaller than 2.5 μm, even when the structure of the present invention is used, background contamination or toner scattering occurs during development, or the fluidity is deteriorated, and toner replenishment and cleaning performance are reduced. May be inhibited. When the particle size is larger than 10 μm, dust in the image and deterioration of resolution may be a problem.

Here, the particle size distribution of the toner can be measured by various methods. In this example, the measurement was performed using a Coulter Multisizer. That is, a Coulter Multisizer IIe type (manufactured by Beckman Coulter, Inc.) was used as the measuring device, and an interface (manufactured by Nikkaki) for outputting the number distribution and volume distribution and a personal computer were connected. 1% Na with sodium
A Cl aqueous solution was prepared. As a measuring method, a surfactant, preferably an alkylbenzene sulfonate, is used as a dispersant in 100 to 150 ml of the electrolytic aqueous solution in an amount of 0.1 to 5 ml.
Then, 2 to 20 mg of the measurement sample was added, and a dispersion treatment was performed for about 1 to 3 minutes using an ultrasonic disperser. Further, 100 to 200 ml of the aqueous electrolytic solution is placed in another beaker, and the sample dispersion liquid is added therein to a predetermined concentration,
A 100 μm aperture was used as the aperture by the Coulter Multisizer IIe type, and 50,000
This was performed by measuring the average of individual particles.

Further, the toner of the present invention is used as a two-component developer together with a carrier. Here, as the carrier used together with the toner, conventionally known carriers can be used, and examples thereof include magnetic powder such as iron powder, ferrite powder and nickel powder, and glass beads. It is preferable to coat the surface with a resin or the like.

In this case, examples of the resin used include polyfluorocarbon, polyvinyl chloride, polyvinylidene chloride, phenol resin, polyvinyl acetal, styrene-acryl resin, and silicone resin.

Here, in the case of a styrene-acryl resin, those having a styrene content of 30 to 90% by weight are preferable. In this case, if the styrene content is less than 30% by weight, the developability decreases, and if the styrene content exceeds 90% by weight, the coating film becomes hard and easily peels off, shortening the life of the carrier.
Further, the resin used may contain an adhesion-imparting agent, a curing agent, a lubricant, a conductive material, a charge control agent, and the like in addition to the above-mentioned resins.

As a method for forming the resin layer, a resin may be applied to the surface of the carrier by a spraying method, a dipping method, or the like, as in the prior art. The amount of the resin used is usually preferably 1 to 10 parts by weight based on 100 parts by weight of the carrier.

The thickness of the resin is 0.02 to 2
μm, particularly preferably 0.05 to
1 μm, more preferably 0.1 to 0.6 μm,
If the film thickness is large, the fluidity of the carrier and the developer tends to decrease, and if the film thickness is small, the film tends to be easily affected by aging, etc.

The carrier used in the two-component developer of the present invention preferably has a saturation magnetization of 20 to 100 emu / g, particularly preferably 30 to 80 emu / g.

If the saturation magnetization of the carrier is less than 20 emu / g, it becomes difficult to hold the developer well on the developing sleeve, carrier adhesion and toner scattering are likely to occur, and the magnetic brush becomes small or Since the density of the magnetic brush becomes coarse, the effect of cleaning the surface of the photoreceptor becomes insufficient, and filming easily occurs. On the other hand, when the saturation magnetization of the carrier exceeds 100 emu / g, the magnetic brush composed of the carrier and the toner on the developing sleeve opposed to the electrostatic latent image on the photoconductor at the time of development is in a state of being tightly tightened. And the reproduction of the halftone are deteriorated, and the chargeability of the toner is also reduced.

On the contrary, the saturation magnetization of the carrier is set to 20 to 100.
By setting the emu / g range, the magnetic brush ears have an appropriate density and an appropriate hardness, so that a certain polishing effect is imparted to the developer layer itself and the photoconductor is finely polished. Thus, the filming material such as toner or adsorbed water on the photoreceptor can be cleaned.

Further, the saturation magnetization is 20 to 100 emu /
The carrier g is excellent in image uniformity and gradation reproducibility, and has a relatively high magnetization, so that the effect of imparting a triboelectric charge to the toner is high, and the effect of improving background contamination is extremely high. high.

The carrier used in the two-component developer of the present invention preferably has a residual magnetization of 20 emu / g or less, particularly preferably 10 emu / g or less, more preferably substantially 0 emu / g.

If the residual magnetization of the carrier is more than 20 emu / g, the carrier itself becomes more cohesive after passing the magnetic field, the mixing property with the toner is reduced, or the carrier is placed on the developing sleeve having a fixed magnet. Are strongly adhered,
Since the transportability of the developer is greatly reduced, image unevenness and the like are likely to occur.

Here, to measure the magnetic properties of the carrier,
Using a magnetometer BHU-60 manufactured by RIKEN ELECTRONICS CO., LTD.
The saturation magnetization and the residual magnetization were determined from the hysteresis curve when the magnetic field was swept to 3 kOe on the carrier filled in the cell having an inner diameter of 7 mmφ and a height of 10 mm.

[0104] Furthermore, the resistivity of the carrier used in two-component developer of the present invention ^is preferably ^{10 7 ~10 1 4 Ω · cm} .

When the specific resistance of the carrier is less than 10 ⁷ Ω · cm, the ears of the developer layer are likely to be rough, and charge injection is also likely to occur, which tends to cause deterioration of image quality such as image unevenness. On the other hand, when the specific resistance of the carrier exceeds 10 ¹⁴ Ω · cm, the rising property of triboelectric charging is remarkably reduced, and the uniform mixing property of the developer is also reduced. Further, the bias potential is hardly applied to the tip of the developer layer.

Here, the specific resistance of the carrier was measured by tapping the carrier in a container having a cross-sectional area of about 10 cm ² and a thickness of about 2 mm, and then adding 1 kg / c to the filled carrier.
A specific resistance was determined by applying a load of m ² and measuring a current value when a voltage of 100 V was applied between the load and the bottom electrode.

The weight average diameter of the carrier used in the two-component developer of the present invention is preferably 30 to 65 μm.

When the weight average diameter of the carrier is less than 30 μm, the carrier is apt to adhere to the photoreceptor, and the photoreceptor, the cleaning blade, the charging roller and the like are easily damaged. Further, when the weight average diameter exceeds 65 μm, especially in combination with a toner having a small particle diameter, the toner holding ability of the carrier is reduced, and uneven density of a solid image, toner scattering, background stain, and the like are likely to occur. Further, the magnetic brush becomes coarse, and it becomes difficult to obtain a high-quality image.

Here, the weight particle size of the carrier was measured by a laser diffraction type particle size distribution meter (manufactured by Horiba, Ltd.).

Here, as an adverse effect caused when the diameter of the carrier is reduced as described above, the fluidity of the developer is reduced, and the transportability of the developer in the developing device is reduced. As a countermeasure for this, there is a change in apparatus conditions such as increasing the stirring intensity in the developing device, but this is not preferable because it causes a problem such as shortening the durability life of the developer and the developing device. Therefore, it is important to ensure a certain level of fluidity as a developer. The two-component developer of the present invention preferably has a fluidity of 20 to 55 seconds.

If the time is longer than 55 seconds, the fluidity is poor, and it is not possible to smoothly charge the replenished toner, resulting in image deterioration. On the other hand, if the time is less than 20 seconds, the developer cannot be transported properly using the frictional resistance of the developer, and a problem arises in the transportability of the developer.

Here, the fluidity of the developer was measured using a bulk density meter having an orifice diameter of 3.00 mmφ.
0.0 g is charged from the inlet of the bulk density measuring instrument while holding down the lower outlet, releasing the lower outlet and simultaneously pressing the stopwatch until the developer is completely discharged from the lower outlet of the inlet. Was measured.

Further, the two-component developer of the present invention preferably has an initial toner concentration of 0.5 to 7.0%, particularly preferably 2.5 to 6.0%.

When the toner concentration is less than 0.5%, the load on the toner when the developer is stirred in the developing device becomes large, and the filming on the photoreceptor or the like during long-term use of the developer is performed. And spent on the carrier and the like, whereby the durability of the developer is reduced and the image quality is easily deteriorated. Further, when the toner concentration exceeds 7.0%, the occurrence of background contamination and toner scattering especially at the time of toner replenishment tends to occur.

The method for cleaning the transfer residual toner on the latent image carrier in the present invention may be any method such as blade cleaning, web cleaning, fur brush cleaning, magnetic brush cleaning, and a cleaning method using a combination thereof. Although preferred, blade cleaning with an elastic blade is more preferably used. The developing method of supplying the collected toner to the developing device includes a method of directly supplying the collected toner to the developing device and a method of temporarily supplying the collected toner to a container containing the replenishing toner, and then supplying the toner to the developing device together with the replenishing toner. Although a method is mentioned, in this invention, it can use preferably in any case.

When the toner of the present invention is used, the container is filled with the toner, and the container filled with the toner is distributed separately from the image forming apparatus, and is mounted on the image forming apparatus by a user and used for image formation. It is common. What is used as the container is not limited, and is not limited to a conventional bottle type or cartridge type.

The image forming apparatus is not limited as long as it is an apparatus for forming an image by electrophotography, and includes, for example, a copying machine, a printer, a facsimile and the like.

[0118]

Next, an embodiment of an image forming apparatus and method according to the present invention will be described. Here, FIG.
FIG. 2 is a schematic configuration diagram illustrating an example of an image forming apparatus and a method according to the present invention, FIG. 2 is a schematic configuration diagram illustrating an example of a main part of the image forming apparatus and the method, and FIG. FIG. 6 is a cross-sectional view illustrating an example of a toner recycling mechanism in which a magnetic field generating unit is provided in a recycling section of FIGS.
3A and 3B are a perspective view and a cross-sectional view illustrating an example of a toner recycling mechanism in which a classification unit is provided in a recycling unit of the image forming apparatus and method.

The copying apparatus main body (100) of FIG. 1 includes a reading optical system (101), a writing optical system (102), an image forming unit (103), a paper feeding unit (104), and the like. The copier (100) includes an image forming unit (103) based on a well-known electrophotographic method, and the image forming unit (103).
Has a drum-shaped photoconductor (131). Around the photoreceptor (131), a charging device (132), an exposing unit (120), and a developing device (13) for performing an electrophotographic copying process along a rotation direction indicated by an arrow (A).
3), a transfer / transport device (600) and a cleaning device (200) are sequentially arranged. Reading optical system (10
1) a light source (122) for irradiating light to a document placed on a document table (121) on the top surface of the copying machine main body; a first mirror (123) for guiding document reflected light in a predetermined direction; It has third mirrors (124) and (125) and an image pickup means (126) such as a CCD for receiving the reflected light of the document guided through a lens or the like (not shown) and performing photoelectric conversion. An image processing unit (not shown) that has received the A / D-converted digital image data output from the imaging unit (126) performs necessary processing on the image data, and writes the optical data based on the image signal after the image processing. The operation of the system (102) forms an electrostatic latent image on the photoconductor (131). Photoconductor (1
31) The electrostatic latent image formed on the developing device (133)
Is formed into a toner image by the paper feeding device (1
The transfer / transport device (6)
00). The transfer paper bearing the toner image is conveyed to a fixing device (135) where it is fixed, and is discharged out of the copying machine, for example, onto a paper discharge tray (150). Although FIG. 1 illustrates a digital image forming apparatus,
The embodiments of the present invention described below can also be applied to an analog image forming apparatus.

Next, in the main part of the image forming apparatus shown in FIG.
1) In principle, the toner adhered on the transfer member is electrostatically transferred to transfer paper by a transfer / conveyance device (600), but a part of the toner remains untransferred on the photoreceptor. The untransferred toner is scraped off the photoconductor (131) by the cleaning blade (211) and the brush roller (212) of the cleaning device (200). The scraped toner is sent from the outlet (210) of the cleaning device (200) to the toner recycling unit (500).

On the other hand, the transfer belt (601) of the transfer / transport device (600) also comes into contact with the photoreceptor in the untransferred portion or the non-image portion, and the toner adheres to the belt (601). Since such toner causes stains on the back of the transfer paper, the blade (6
02). The scraped toner is sent from the outlet (603) to the toner recycling unit (700). This toner recycling unit (700)
Has the same configuration as the toner recycling unit (500) attached to the cleaning device (200).

Then, an elastic tube (510) described later,
Via (710), the toner flow on the air reaches the recycle / discard switching unit (800). When recycling the collected toner of the cleaning device (200) and the transfer / transport device (600), the elastic tube (5) is used.
10) to the nozzle (801), the elastic tube (710)
Is inserted into the nozzle (802) and both toners are discarded, the elastic tube (510) is connected to the nozzle (81).
In 1), an elastic tube (710) is inserted into the nozzle (812). When recycling the collected toner from the cleaning device and discarding the collected toner from the transfer / transport device, the elastic tube (510)
Is inserted into the nozzle (801), and the elastic tube (710) is inserted into the nozzle (812). The nozzle port not connected to the tube is plugged to prevent toner leakage. The toner flow recycled by the nozzles (801) and (802) enters the toner replenishing hopper (310) from the inlet (400) of the developing device (133) via the tube (803), and is supplied with a new toner (not shown). The toner is mixed with new toner from the toner bottle to become a replenishing toner. On the other hand, the toner flow flowing through the tubes connected to the waste nozzles (811) and (812) enters the waste bottle (810), is accumulated, and is disposed of from or together with the bottle as necessary.

Further, the image forming apparatus and method of the present invention
In particular, by providing a toner sorting mechanism using magnetic field generation means in the recycling section, transfer paper fibers, fillers such as talc, kaolin and calcium carbonate, suspended matter in the air, and fine powder It is possible to prevent toner having low properties such as toner having low magnetization such as toner and toner having low coloring degree in which the colorant is not sufficiently dispersed, from being re-mixed into the developing section, and thereby the image over time can be prevented. In addition to being able to drastically suppress the reduction in density, the increase in background contamination and toner scattering, and the occurrence of filming, the occurrence of carrier spent due to fine powder toner, image defects such as transfer unevenness and white spots, etc. Generation can be suppressed.

Next, an example of the toner recycling mechanism in which the magnetic field generating means is provided in the recycling section will be described with reference to the sectional view of FIG. A sleeve (804) having a built-in magnet is disposed inside the recycle / disposal switching unit (800) of FIGS. 2 and 3, and a driving unit (not shown).
Thus, it is driven to rotate in the direction of the arrow. Further, it is possible to apply a bias to the sleeve as needed, and the bias voltage applied at this time may be AC or DC. Here, when applying a bias voltage, about 500 to 3000 V is preferable. If the applied bias voltage is lower than 500 V, the effect of applying the bias is less likely to be exhibited, while if it is more than 3000 V, leakage tends to occur, which is not preferable. Also,
When applying a bias, it is preferable to apply the bias so that the polarity is opposite to the polarity of the toner. Also,
Reference numeral (805) denotes a scraping blade for scraping the toner carried and conveyed on the sleeve (804) from the surface of the sleeve (804). Scraping blade (80
The toner scraped off in 5) is transferred to the tube (80).
3), is discharged out of the recycle / waste switching unit (800), enters the toner replenishing hopper (310) from the inlet (400) of the developing device (133), and receives new toner from a new toner bottle (not shown). When mixed, it becomes a replenishing toner. In addition, (806) is a waste bottle (8) that removes extraneous matter such as toner, paper fibers and filler remaining on the sleeve.
10) A brush for scraping off. The brush (806) is rotationally driven at a low speed in the counter direction with the sleeve.

Next, the flow of toner in the toner recycling mechanism will be described. Cleaning device (200)
The toner recovered from the transport device (600) is transported into the toner recycling mechanism shown in FIG. 2 by the nozzles (801) and (802), and is supplied to the sleeve (804). Here, the collected toner is placed in a sleeve (80
4) Attach to the surface of the sleeve (804) by the magnetic force of the magnet in (4) and the applied bias voltage, and scrape the blade (805) with the rotation of the sleeve (804).
And is scraped off the surface of the sleeve (804) by the scraping blade (805), and the tube (8)
03) to the developing device (133).

On the other hand, the toner having a weak magnetic force, and deposits such as fibers and fillers such as transfer paper do not adhere to the sleeve (804) but fall downward, and fall into the waste bottle (81) as waste toner.
Collected in 0). Also, a scraping blade (805)
Adhered matter such as toner remaining on the sleeve (804) without being scraped off by the brush is scraped off by a brush and falls downward, and similarly, as a waste toner, a waste bottle (81)
Collected in 0).

The image forming apparatus and method of the present invention
In particular, by providing a toner sorting mechanism using a classification means in the recycling section, fibers of transfer paper mixed in the collected toner, fillers such as talc, kaolin and calcium carbonate, suspended matters in the air, and further aggregated It is possible to prevent toner and the like having deteriorated properties such as toner from being re-mixed into the developing unit, thereby reducing image density over time,
In addition to significantly reducing the occurrence of background contamination and toner scattering, filming, and the like, it is possible to further suppress the occurrence of image defects such as transfer unevenness and white spots.

Next, an example of a toner recycling mechanism provided with a classifying means in the recycling section will be described with reference to the perspective views and sectional views of FIGS. 4 and 5, outlets (32) and (43) for discharging the toner collected from the cleaning device (200) and the transfer / transport device (600) are provided at the back side of the apparatus main body. 3
2) and (43) are connected to a pipe (60) connected to the collected toner processing device (70) via paths (65) and (66).

The transport of the collected toner to the toner processing device (70) is performed by a motor (61) using gears (62) and (6) by a transport screw (64) built in a pipe (60).
The rotation is performed by receiving the driving force via 3). This pipe (60) is connected to the collected toner processing device (7).
0), a toner classifying device (80) as a classifying means and a toner transfer device (90) for transferring the collected toner to the developing device (133) are provided in the case (71). ing.

The toner classification device (80) has a cylindrical classification network (81), and the classification network (81) is a holder having a discharge port (83A) formed through a cylindrical member (82) having the same diameter. (83). This holder (8
3) is adapted to be rotated by receiving rotation from the conveying screw (64), whereby the classification network (81) is rotated.
Is also rotated. The holder (83) has a case (7
A guide shaft (84) extending to the outside of 1) is integrally provided, and the guide shaft (84) is rotatably supported on a case (71) via a bearing (72) and movably in a thrust direction. Have been. The tip of the guide shaft (84) is rotatably connected to a classifier moving means (85) (FIG. 4) outside the case (71). This classification network moving means (85)
Has a wire (87) wound up or down by a movement motor (86) (FIG. 4), and a spring (88) is interposed in the wire (87).

On the other hand, the toner transfer device (90) is disposed below the toner classification device (80), and the case (71)
A screw pump (92) and a screw pump (92) are arranged so as to be connected thereto. This screw pump (92) is a female screw type stator (94) having a double pitch spiral groove made of an elastic body such as rubber inserted into a holder (93) attached to a case (71). And a male screw rotor (95) rotatably fitted in the stator (94). The rotor (95) is integrally connected to one end of the shaft of the transport screw (91) by a screw or a pin, and the other end of the transport screw (91) penetrates the case (71), and the case (71) Gear outside (9
6) and (97) are driven by the drive motor (98). An opening (73) is formed in the lower right part of the case (71), and the opening (73) communicates with a waste bottle (not shown).

At this time, the flow of the collected toner is such that the collected toner that has passed through the pipe (60)
7) It is dropped by the classifier (81). Here, the toner that has passed through the classification network (81) is transported by the conveying screw (91).
The developer drops to the upper side and is transferred to the developing device (133) by a screw pump (92) connected to the screw. At this time, the toner pump of FIG.
When the air is supplied from the air pump (402), the air promotes fluidization of the toner, and the transfer by the screw pump (92) is ensured. Furthermore, if a screw pump (92) is used, the hose (401) connected to its discharge side is a flexible tube, for example, made of soft vinyl chloride, silicon, nylon, or polytetrafluoroethylene-based fluororesin. Therefore, the transfer path can be freely set, and the transfer can be freely performed in any direction including up, down, left, and right. Moreover, the screw pump (92)
The transfer of the toner due to no mechanical stress on the toner is very effective for transferring the toner to be recycled.

On the other hand, the adhered substances such as aggregated toner, fibers such as transfer paper, fillers, etc., which could not pass through the classification network (81), fall downward from the outlet (83A) of the holder (83) and become waste toner. Waste bottle (not shown) from opening (73)
Will be collected.

Particularly, at this time, the true specific gravity of the toner is 1.35.
Since it is higher than ordinary toner, that is, 1.60 g / cm ³ , it can not only improve the accuracy of classifying fibers such as transfer paper having a low specific gravity, but also deposits such as fillers, and can be included in the collected toner. It is possible to select the toner from the aggregated toner, thereby suppressing the occurrence of image defects such as transfer unevenness and white spots due to the mixing of the aggregated toner and the like.

[0135]

The present invention will be described below in more detail with reference to examples. However, the present invention is not limited to these. The parts in the examples represent parts by weight.

<Production Example 1 of Metal Material> Mn-containing maghematite particles A (saturation magnetization at the time of applying 10 kOe: 15.0)
emu / g, average particle size: 0.28 μm), aniline black was fixed to the particle surface using 8% by weight mechanomill (manufactured by Okada Seiko) or mechanofusion system (manufactured by Hosokawa Micron), and the surface treatment of Production Example 1 A metal material A was obtained.

<Production Example 2 of Metal Material> Ti-containing hematite particles A (saturation magnetization at the time of applying 10 kOe: 14.3 em)
u / g, average particle diameter: 0.25 μm) and aniline black was fixed to the particle surface using an 8% by weight mechanomill (manufactured by Okada Seiko) or a mechanofusion system (manufactured by Hosokawa Micron), and the surface treatment of Production Example 2 was performed. Metal material B
I got

<Production Example 3 of Metallic Material> Mn-containing hematite particles A (saturation magnetization when applying 10 kOe: 2.6 emu)
/ G, average particle diameter: 0.03 μm) and aniline black is fixed to the particle surface using 8% by weight mechanomill (manufactured by Okada Seiko Co., Ltd.) or mechanofusion system (manufactured by Hosokawa Micron Co., Ltd.). Material C was obtained.

<Production Example 4 of Metal Material> Magnetite particles A (saturation magnetization at the time of applying 10 kOe: 76.1 emu /
g, average particle diameter: 0.28 μm), and aniline black was fixed to the particle surface using an 8% by weight mechanomill (manufactured by Okada Seiko Co., Ltd.) or a mechanofusion system (manufactured by Hosokawa Micron Co., Ltd.). D was obtained.

(Example 1) Binder resin Polyester resin (terephthalic acid, n-dodecenyl succinic anhydride, polyoxypropylene- (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene -(2.1) Polyester resin synthesized from 2,2-bis (4-hydroxyphenyl) propane and trimellitic acid, Tg: 63 ° C) 85 parts Styrene-acrylic resin (Styrene and n-butyl methacrylate) Copolymer, Tg: 61 ° C.) 15 parts Colorant Mn-containing maghematite particles A (saturation magnetization at 10 kOe application: 15.0 emu / g, average particle diameter: 0.28 μm) 20 parts Charge control agent Azo-based iron complex 2 parts Release agent De-free fatty acid type carnauba wax (melting point: 83 ° C) 5 parts Mix the above materials with Henschel mixer After the, 1
The mixture was melted and kneaded by a biaxial kneader heated to 40 ° C. The kneaded product was water-cooled, coarsely pulverized by a cutter mill, pulverized by a fine pulverizer using a jet stream, and then used to obtain base particles using an air classifier. Base particles 100 parts Additive Silica (hexamethyldisilazane surface-treated product, average primary particle diameter: 0.012 μm) 0.9 parts Titania (isobutyltrimethoxysilane surface-treated product, average primary particle size: 0.015 μm) 0 .6 parts Further, the above-mentioned material was mixed with a Henschel mixer at a peripheral speed of a stirring blade tip of 20 m / sec. Set to become 300
Mixing was carried out for 2 seconds, and then air sieving was performed with a sieve having openings of 100 μm to obtain the toner of Example 1.

(Example 2) The coloring agent of Example 1 was replaced with Ti-containing hematite particles A (saturation magnetization: 10 kOe applied: 1).
The toner of Example 2 was obtained in the same manner as in Example 1 except that the toner composition was changed to 4.3 emu / g, and the average particle diameter was 0.25 μm.

Example 3 The coloring agent of Example 1 was replaced with Mn-containing hematite particles A (saturated magnetization when 10 kOe was applied:
The toner of Example 3 was obtained in the same manner as in Example 1, except that the particle size was changed to 2.6 emu / g, and the average particle diameter was 0.03 μm.

(Example 4) Except that the colorant of Example 1 was changed to the surface-treated metal material A of Production Example 1 of the metal material,
In the same manner as in Example 1, the toner of Example 4 was obtained.

(Example 5) The coloring agents used in Example 4
Further, a toner of Example 5 was obtained in the same manner as in Example 4, except that 3 parts of carbon black (# 44: manufactured by Mitsubishi Chemical Corporation) was added.

Example 6 A toner of Example 6 was obtained in the same manner as in Example 1 except that the colorant of Example 1 was changed to 30 parts of the surface-treated metal material B of Production Example 2 of the metal material. Was.

Example 7 A toner of Example 7 was obtained in the same manner as in Example 1 except that the colorant of Example 1 was changed to 15 parts of the surface-treated metal material C of Production Example 3 of the metal material. Was.

(Embodiment 8) The procedure of Example 7 was repeated, except that the surface-treated metal material C of Example 7 was changed to 40 parts.
Thus, a toner of Example 8 was obtained.

Example 9 Mn-containing hematite particles B (saturation magnetization when 10 kOe was applied:
(0.9 emu / g, average particle size: 0.02 μm) A toner of Example 9 was obtained in the same manner as in Example 1, except that the amount was changed to 30 parts.

Example 10 The coloring agent of Example 1 was replaced with Ti
Containing hematite particles B (saturation magnetization at the time of applying 10 kOe:
(Example 8.2) The toner of Example 10 was obtained in the same manner as in Example 1 except that the particle size was changed to 8.2 emu / g, and the average particle diameter was 0.9 µm.

Example 11 Example 1 was repeated in the same manner as in Example 1 except that the polyester resin was changed to 50 parts and the styrene-acrylic resin was changed to 50 parts.
Thus, No. 1 toner was obtained.

Example 12 A toner of Example 11 was obtained in the same manner as in Example 1 except that the release agent of Example 1 was omitted.

Example 13 The toner of Example 13 was prepared in the same manner as in Example 1 except that the release agent of Example 1 was changed to a low molecular weight polypropylene wax (Viscol 550P: manufactured by Sanyo Chemical Industries, Ltd.). Obtained.

(Example 14) In the same manner as in Example 1, except that (1) the feed amount of the pulverization was increased and (2) the air pressure of the pulverization was reduced in the production of the pulverizer. 14 toners were obtained.

Comparative Example 1 A toner of Comparative Example 1 was obtained in the same manner as in Example 1 except that the colorant of Example 1 was changed to 10 parts of carbon black (# 44: manufactured by Mitsubishi Chemical Corporation). Was.

(Comparative Example 2) The coloring agent of Example 1 was replaced with magnetite particles A (saturation magnetization at the time of application of 10 kOe: 76.1).
emu / g, average particle size: 0.28 μm) A toner of Comparative Example 2 was obtained in the same manner as in Example 1, except that the amount was changed to 10 parts.

Comparative Example 3 The procedure of Comparative Example 2 was repeated, except that the magnetite particles A in Comparative Example 2 were changed to 20 parts.
A toner of Comparative Example 3 was obtained.

(Comparative Example 4) [0157] Except that the colorant of Example 1 was changed to the surface-treated metal material D of Production Example 4 of the metal material,
In the same manner as in Example 1, a toner of Comparative Example 4 was obtained.

Comparative Example 5 The procedure of Comparative Example 2 was repeated, except that the magnetite particles A in Comparative Example 2 were changed to 35 parts.
Thus, a toner of Comparative Example 5 was obtained.

Comparative Example 6 A toner of Comparative Example 6 was obtained in the same manner as in Example 9 except that the amount of the Mn-containing hematite particles B in Example 9 was changed to 70 parts.

(Comparative Example 7) A toner of Comparative Example 7 was obtained in the same manner as in Comparative Example 2, except that the magnetite particles A in Comparative Example 2 were changed to 110 parts.

Examples 1 to 15 and Comparative Examples 1 to 7
The toner was measured for saturation magnetization, true specific gravity, dielectric loss tangent, and weight average diameter. Table 1 shows the results.

[0162]

[Table 1]

<Example of Carrier Production> Core material Cu-Zn ferrite particles (weight average diameter: 45 μm) 5000 parts Coating material Toluene 450 parts Silicone resin SR2400 (manufactured by Dow Corning Toray Silicone, nonvolatile content 50%) 450 parts aminosilane SH6020 (manufactured by Dow Corning Toray Silicone Co., Ltd.) 10 parts Carbon black 10 parts A coating solution is prepared by dispersing the above coating material with a stirrer for 10 minutes, and the coating solution and the core material are stirred in a fluidized bed with a rotary bottom plate disk. The coating solution was applied to a core material, which was fed into a coating apparatus having a blade and performing coating while forming a swirling flow. Further, the obtained carrier is baked in an electric furnace at 250 ° C. for 2 hours to have a thickness of 0.5 μm.
Carrier particles (saturation magnetization of 65 emu when 3 kOe is applied)
/ G, 3 emu / g of residual magnetization upon application of 3 kOe, a specific resistance of 3.2 × 10 ⁸ Ω · cm, and a weight average diameter of 45 μm).

<Production Example of Developer> 2.5 parts of each of the toners of Examples 1 to 12 and Comparative Examples 1 to 7 and 97.5 parts of the carrier of the above Production Example were mixed with a turbuler mixer to obtain a fluidity. Obtained a developer for 29 to 37 seconds.

[Examples and Comparative Examples] Each of the above toners and developers was set in a copying machine having an image forming main unit shown in FIG. 2 and an image forming apparatus shown in FIG. In this environment, continuous copying of 100,000 sheets was performed, the following various evaluations were made, and ranking was made in five stages based on the following criteria. Table 2 shows the results.

In the fifteenth embodiment, the toner and the developer of the first embodiment are provided with a toner recycling mechanism having a main part for image formation shown in FIG. 2 and a recycle part shown in FIG. 3 having a magnetic field generating means. Further, the apparatus was set in a copying machine having the image forming apparatus shown in FIG. 1, and 100,000 sheets were continuously copied under the normal temperature / humidity environment, and the following various evaluations were similarly performed. According to the standard, ranking was performed in five stages. Table 2 shows the results.

Further, in the sixteenth embodiment, the toner and developer of the first embodiment are provided with a toner recycling mechanism having a main image forming portion shown in FIG. 2 and a classifying means in the recycling portion shown in FIGS. Was set in a copying machine having the image forming apparatus shown in FIG. 1, and 100,000 sheets were continuously copied under the normal temperature / humidity environment, and the following various evaluations were similarly performed. 5 according to the following criteria
The ranking was made at each stage. Table 2 shows the results.

(Durability) The durability was evaluated as 100,00
After continuous copying of 0 sheets, the image density of the solid portion was changed to X-Rite 9
38, and evaluated by the difference from the image density of the same portion in the initial image. Here, the lower the image density from the initial stage, the lower the durability.

(Background dirt) The background dirt was evaluated in the initial and 10
After continuous copying of 000 sheets, the degree of occurrence of background contamination in the non-image area was visually evaluated.

(Scattering of Toner) Toner scattering was evaluated by visually observing the degree of scattering of toner in a copying machine at the initial stage and after continuous copying of 100,000 sheets.

(Filming) Evaluation of filming is as follows.
After continuous copying of 100,000 sheets, the degree of filming of the photoconductor was visually evaluated.

(Transfer unevenness / white spots) The transfer unevenness / white spots were evaluated at the initial stage and after continuous copying of 100,000 sheets, and after 10 continuous A3-size solid images were output, the transfer unevenness / white spots in the image were output. The degree of omission was visually evaluated.

[0173]

[Table 2] Criteria ◎: Very good level ○: Good level □: General level △: Level that has no practical problem ×: Level that has practical problem

In Comparative Example 2, a sufficient image density was not obtained, and the amount of toner consumption was clearly larger than those in the other Examples and Comparative Examples. Was.

[0175]

As is apparent from the above detailed and concrete description, according to the present invention, even in the continuous output of a large number of images having a large image area, background contamination and toner scattering do not occur, Excellent in properties, less occurrence of filming, etc., and even when using a small particle size toner,
This provides an extremely excellent effect of providing a black toner for a two-component developer, a two-component developer, a toner container, an image forming apparatus, and an image forming method capable of obtaining stable image quality over a long period of time.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an example of an image forming apparatus and a method according to the present invention.

FIG. 2 is a schematic configuration diagram showing an example of a main part of an image forming apparatus and a method according to the present invention.

FIG. 3 is a cross-sectional view illustrating an example of a toner recycling mechanism in which a magnetic field generating unit is provided in a recycling unit of the image forming apparatus and method according to the present invention.

FIG. 4 is a perspective view illustrating an example of a toner recycling mechanism in which a classification unit is provided in a recycling unit of the image forming apparatus and method according to the present invention.

FIG. 5 is a cross-sectional view illustrating an example of a toner recycling mechanism in which a classification unit is provided in a recycling unit of the image forming apparatus and method according to the present invention.

[Explanation of symbols]

 32 Discharge port 43 Discharge port 60 Pipe 61 Motor 62 Gear 63 Gear 64 Conveyor screw 65 Path 66 Path 67 Toner discharge unit 70 Recovered toner processing device 71 Case 72 Bearing 73 Opening 80 Toner classification device 81 Classification network 82 Cylindrical member 83 Holder 83A Drain Outlet 84 Guide shaft 85 Classification net moving means 86 Moving motor 87 Wire 88 Spring 90 Toner transfer device 91 Conveying screw 92 Screw pump 93 Holder 94 Female screw type stator 95 Male screw type rotor 96 Gear 97 Gear 98 Drive motor 100 Copier main body 101 Reading optical System 102 Writing optical system 103 Image forming unit 104 Paper feeding unit 120 Exposure means 121 Document table 122 Light source 123 First mirror 124 Second mirror 125 Third mirror 126 Imaging means 131 Drum-shaped photoreceptor 132 Charging device 133 Developing device 135 Fixing device 140 Paper feeding device 150 Paper ejection tray 200 Cleaning device 210 Exit 211 Cleaning blade 212 Brush roller 310 Toner supply hopper 400 Inlet 401 Hose 402 Air pump 500 Toner Recycle unit 510 Elastic tube 600 Transfer / transport device 601 Transfer belt 602 Blade 603 Discharge port 700 Toner recycle unit 710 Elastic tube 800 Recycle / discard switching unit 801 Nozzle 802 Nozzle 803 Tube 804 Sleeve 805 Blade 806 Brush 810 Waste bottle 811 Nozzle 812 Nozzle A Rotation direction

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 9/087 G03G 9/08 301 9/09 15/08 507L 9/113 507D 15/08 507 21/00 326 15/09 9/08 361 21/10 331 9/10 352 9/08 302 (72) Inventor Toyoshi Sawada 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company, Ltd. (72) Inventor Yoichiro Watanabe 1-3-6 Nakamagome, Ota-ku, Tokyo Co., Ltd. Ricoh Company (72) Inventor Masahide Yamashita 1-3-6 Nakamagome, Ota-ku, Tokyo Co., Ltd. Ricoh Company (72) Inventor Akihiro Koban Ota, Tokyo 1-3-6 Nakamagome, Ward Ricoh Co., Ltd. (72) Inventor Keiko Shiraishi 1-6-6 Nakamagome, Ota-ku, Tokyo Fterm in Ricoh Co., Ltd. 2H005 AA01 AA0 2 AA03 AA06 AA08 BA06 CA08 CA12 CA14 CA21 CB03 CB07 CB13 CB18 DA08 EA01 EA02 EA05 EA07 EA10 FA02 2H031 AC01 AD03 AE01 AE02 BA08 BA09 BB01 CA07 CA10 2H077 AA37 AC02 AC04 AC12 AC16 AD35 AD01 AD32 GB01 JA03 JA04 JA12 JB02 KH01

Claims (25)

[Claims] An agitating means stirs a two-component developer composed of a toner and a carrier to frictionally charge toner particles, and places the toner particles on a rotatable substantially cylindrical developer carrier having a magnetic field generating means therein. A black toner for a two-component developer used in an image forming apparatus (developing apparatus) that holds a two-component developer containing charged toner particles and develops an electrostatic latent image formed on an image carrier; The toner has a binder resin containing at least a colorant made of a metal material, and has a saturation magnetization of 0.01 to 10 emu / g and a true specific gravity of 1.35 to 1.60 g / cm ^3. A black toner for a two-component developer, comprising: 2. The method according to claim 1, wherein the metal material is made of Fe, Mn, Ti, Cu, Si, C on a surface of hematite or maghematite.
2. The black toner for a two-component developer according to claim 1, wherein one or more compounds selected from the compounds of the respective elements are present. 3. The black toner for a two-component developer according to claim 1, wherein the metal material is a metal material blackened by a surface treatment with a pigment and / or a dye. 4. The method according to claim 1, wherein said colorant contains 0.01 to 5% by weight of carbon black.
4. The black toner for a two-component developer according to any one of items 1 to 3. 5. The toner has a saturation magnetization of 0.05 to 3 em.
5. The black toner for a two-component developer according to claim 1, wherein the ratio is u / g. 6. The toner has a true specific gravity of 1.40 to 1.55 g.
/ Cm ³ , the black toner for a two-component developer according to any one of claims 1 to 5. 7. The toner has a dielectric loss tangent of 2.5 × 10 ^−3.
The black toner for a two-component developer according to any one of claims 1 to 6, wherein the toner density is from 7.5 to ^10-3 . 8. The metal material has an average particle size of 0.01 to 0.01.
The black toner for a two-component developer according to any one of claims 1 to 7, wherein the thickness is 0.8 µm. 9. The two-component developer according to claim 1, wherein the content of the metal material is 10 to 25 parts by weight based on 100 parts by weight of the binder resin. Black toner. 10. The black toner for a two-component developer according to claim 1, wherein at least a polyester resin is used as the binder resin. 11. The black toner for a two-component developer according to claim 1, wherein the toner contains a release agent. 12. The two-component composition according to claim 1, wherein said release agent is at least one of carnauba wax, montan wax and oxidized rice wax. Black toner for developer. 13. The toner according to claim 1, wherein an additive is externally added to the toner, and at least silica and / or titania are used as the additive. Black toner for component developer. 14. The toner has a weight average diameter of 2.5 to 10
14. The black toner for a two-component developer according to claim 1, wherein the particle diameter is μm. 15. A two-component developer using the black toner for a two-component developer according to claim 1 and a carrier. 16. The two-component developer according to claim 15, wherein said carrier is coated with a coating material containing a silicone resin. 17. A toner container filled with the black toner for a two-component developer according to claim 1. Description: 18. An image forming apparatus for developing an electrostatic latent image formed on a latent image bearing member, wherein the black toner for a two-component developer according to claim 1 is used. Characteristic image forming apparatus. 19. A step of forming an electrostatic latent image on a latent image carrier, a step of developing the obtained electrostatic latent image, a step of transferring the developed toner image to a transfer material, 15. The two-component developer black toner according to claim 1, wherein the image forming apparatus includes at least a step of cleaning the toner remaining in the image forming apparatus and a step of recycling the cleaned toner to the developing unit. An image forming apparatus comprising: 20. A step of forming an electrostatic latent image on the latent image carrier, a step of developing the obtained electrostatic latent image, a step of transferring the obtained toner image to a transfer material, 20. The image forming apparatus according to claim 19, further comprising a step of cleaning the residual toner and a step of recycling the cleaned toner to the developing unit, wherein a magnetic field generating mechanism is provided in the recycling step. The image forming apparatus as described in the above. 21. A step of forming an electrostatic latent image on the latent image carrier, a step of developing the obtained electrostatic latent image, a step of transferring the obtained toner image to a transfer material, 21. An image forming apparatus having at least a step of cleaning toner remaining in a printer and a step of recycling the cleaned toner to a developing unit, wherein a classification mechanism is provided in the recycling step. An image forming apparatus according to claim 1. 22. An image forming method for developing an electrostatic latent image formed on a latent image carrier, wherein the black toner for a two-component developer according to claim 1 is used. Characteristic image forming method. 23. After developing the electrostatic latent image formed on the latent image carrier and transferring the developed toner image to a transfer material,
Cleaning the toner remaining on the latent image carrier,
15. An image forming method for recycling a cleaned toner to a developing unit, wherein the black toner for a two-component developer is used in any one of claims 1 to 14. 24. After developing the electrostatic latent image formed on the latent image carrier and transferring the developed toner image to a transfer material,
Cleaning the toner remaining on the latent image carrier,
24. The image forming method according to claim 23, wherein in the image forming method for recycling the cleaned toner to the developing unit, a magnetic field generating unit is used for recycling the cleaned toner to the developing unit. 25. After developing the electrostatic latent image formed on the latent image carrier and transferring the developed toner image to a transfer material,
Cleaning the toner remaining on the latent image carrier,
25. The image forming method according to claim 23, wherein in the image forming method for recycling the cleaned toner to the developing unit, a classification unit is used for recycling the cleaned toner to the developing unit.