JP2001350291A - Toner for formation of electrostatic image, method forming image and device for image formation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner for electrostatic image formation and to provide a method and device for image formation in which high quality images can be obtained while reducing the size of the device and cost by decreasing the number of parts and integrating the functions. SOLUTION: The toner for electrostatic image formation contains at least a binder resin and magnetic powder and it contains 10 to 40 wt.% of a magnetic material consisting of the magnetic powder coated with a coloring agent and colored into black.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming toner used in electrophotography, electrostatic printing, and the like, an image forming method, and an image forming apparatus.

[0002]

2. Description of the Related Art In a dry two-component developer used in a two-component developing method, fine toner particles are held on the surface of a relatively large particle by an electric force generated by friction between the two particles. When the image is close to the image, the suction force in the latent image direction on the toner particles due to the electric field force generated by the electrostatic latent image,
By overcoming the bonding force between the toner particles and the carrier particles, the toner particles are attracted to and adhered to the electrostatic latent image, so that the electrostatic latent image is visualized. The developer is used repeatedly while replenishing the toner consumed by the development.

Conventionally, non-magnetic toners using carbon black as a colorant have been mainly used as toners in two-component developers. When the reverse charge or weakly charged toner is generated in the charge amount, there is a problem that the background fog is easily generated. As a countermeasure, a method has been devised in which a magnetic material is contained and a ground bias is prevented by using a magnetic bias.However, if the amount of the magnetic material is large, the image density cannot be obtained, so that there is an appropriate range of the amount of the magnetic material. Was. In addition, when the amount of the magnetic material is small, the magnetic material alone is insufficient in terms of the degree of coloring, and it has been required to use the carbon material together with carbon black. However, a large amount of carbon black is contained for the purpose of improving the degree of coloring. In addition, there was a problem that the ground cover margin was reduced.

[0004] As a fixing method in electrophotography, a heat roller method is widely and generally used because of its high energy efficiency. Further, as in recent low-temperature fixing and high-speed copying for energy saving, thermal energy given to toner at the time of fixing tends to be small. It is generally attempted to improve the low-temperature fixability by using a resin or wax having a low softening point as the toner used for such low-temperature fixing. However, since such a low-temperature fixing toner is thermally weak, it is known that the toner is hardened by heat of a machine used or heat during storage, that is, so-called blocking occurs. Further, it is difficult to secure a sufficient fixing temperature range, and even if a polyester resin which is said to have relatively good heat preservability in spite of good low-temperature fixability is used, a toner which has solved this problem can still be obtained. Not.

To solve these problems, several methods using two types of polyester resins having different characteristics have been proposed. For example, Japanese Patent Application Laid-Open No. 60-9034
Japanese Patent Application Laid-Open No. 4 (1994) discloses that a non-linear polyester resin and a linear polyester resin are mixed.
No. 4-15755 discloses that Tg is 50 ° C. or higher and softening point is 2
Crosslinked polyester resin of 00 ° C or less and softening point of 150 ° C
Hereinafter, mixing with a linear polyester resin having a MW of 3,000 to 50,000 is disclosed.
JP-A-822267 discloses a non-linear high-molecular polyester resin having a MW of 5,000 or more and a dispersion ratio of 20 or more and a MW of 1,0.
JP-A-3-2 discloses that a non-linear polyester resin having a dispersion ratio of from 0.00 to 5,000 and a dispersion ratio of 4 or less is contained.
Japanese Patent No. 29264 discloses that an organic metal compound composed of a linear polyester resin having an acid value of 5 to 60 and a non-linear polyester resin having an acid value of less than 5 is contained. Discloses that a saturated polyester resin is mixed with a different polyester resin having an acid value ratio of 1.5 or more.

However, in recent years, low-temperature fixing has been increasingly advanced, and further low-temperature fixing has been demanded. In addition to downsizing of the apparatus, securing of low-temperature fixing property and fixing temperature range when a low-load fixing apparatus is used. It is becoming difficult to balance heat conservation with heat. In addition, in this two-component developing method, it is necessary to keep the mixture ratio of the carrier and the toner (toner density) constant in order to obtain a stable image density, and it is necessary to mount a toner replenishing mechanism, a sensor, and the like for that purpose. In addition, there is a drawback that the developing device becomes large and its operation mechanism becomes complicated.

On the other hand, the one-component developing method does not use a developer in which carrier particles and toner particles are mixed as in the two-component developing method, but uses a toner containing an electric force or a magnetic material generated by friction between the toner and the developing sleeve. When the toner is held on the developing sleeve by the magnetic force between the developing sleeve and the built-in magnet, and when the electrostatic latent image is brought close to the electrostatic latent image, the attracting force to the toner image due to the electric field formed by the electrostatic latent image is applied to the toner particle. By overcoming the bonding force between the toner and the developing sleeve, the toner particles are attracted onto the electrostatic latent image and the electrostatic latent image is visualized. Therefore, in the one-component developing method, there is no need to control the toner concentration, and thus there is an advantage that the developing device can be downsized. However, since the number of toner particles in the developing area is smaller than that in the two-component developing method, The supply of toner to the printer was not sufficient, and it was difficult to cope with a high-speed copying machine.

On the other hand, there is known a developing device which uses a two-component developer and does not require a toner density detecting means, and takes in toner by movement of the developer. However, in this developing device, the amount of toner taken in is different between a portion where the developer is active and a portion where the developer is not active, or a portion where the amount of the developer is large and a portion where the amount of the developer is small. Density unevenness and background fog are likely to occur. In view of this, there is a technology that solves density unevenness and background fogging in the longitudinal direction of the apparatus by disposing two toner supply members in a toner hopper and passing a developer through a path formed by each toner supply member. Kaisho 63-4282
No. 6,086,045. However, the technique disclosed in the above publication has a problem that the developing unit becomes large and the cost increases because two toner supply members are used. Further, Japanese Unexamined Patent Application Publication No.
Japanese Patent Application Laid-Open No. 97833 discloses a technique for resolving the above-mentioned drawbacks, but it is not sufficient for resolving the aforementioned density unevenness.

In recent years, the demand for high-quality images has been increasing in the market, and it is no longer possible to obtain sufficiently high image quality with a conventional toner having a volume average particle diameter of 10 to 15 μm.
Further, a toner having a small particle size is required.

[0010]

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an electrostatic image forming toner of the present invention in view of the above prior art, and further reduces the number of parts.
It is an object of the present invention to provide an image forming method and apparatus capable of obtaining a high-quality image while reducing the size and cost by integrating functions.

[0011]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies and found that a toner having at least a binder resin and a magnetic powder has a magnetic material whose surface is blackened by being coated with a coloring agent. It has been found that the above disadvantage can be solved by containing 〜40 wt%. here,
By including in the toner a magnetic material whose surface is improved in jetness by coating with a colorant, the use of carbon black, which is one of the causes of ground fogging, can be eliminated or reduced, and the magnetic bias Low charge due to effect,
Since it is possible to reduce the responsiveness of the toner having a small charge amount such as the reverse charge amount due to the bias, it is possible to further improve the margin such as ground fogging. Here, when the amount of the magnetic material is less than 10 wt%, the effect of improving the background fogging by the magnetic bias effect is low, and when it is more than 40 wt%, the magnetic bias effect is too large and the developing ability is extremely reduced, and the image density is reduced. The problem was seen in the point of.

The colorant used for the blackening is preferably a pigment and / or a dye. Further, since the coloring pigment is particularly carbon black, a black magnetic substance having a high jet blackness can be obtained, and there is an advantage that a desired black can be easily obtained by coating a small amount of the magnetic substance.

Further, the magnetic powder coated with the magnetic powder by carbon black is more preferably 10 to 30 watts.
It has been found that the above drawbacks can be solved by containing t%.

Further, when the toner contains carbon black therein, the content of carbon black is 6 watts.
It is necessary to be less than t%. Here, with respect to the carbon black content, when the content is more than 6 wt%, occurrence of fogging due to the carbon black content is observed, and the smaller the amount, the better the fog is improved. At most, 6 wt% is the limit value. , The ground fogging was the best in the case of not containing. More preferably, it is not contained.

The average particle diameter of the magnetic particles is 0.20.
When the thickness is from 0.40 μm, preferably from 0.2 to 0.30 μm, the dispersibility of the magnetic substance in the resin is appropriately dispersed, and a coloring degree as a substitute for a black coloring agent such as carbon black is obtained. be able to. Here, when the thickness is less than 0.2 μm, aggregation of the magnetic material in the resin is more likely to occur, and ground fogging or the like due to poor dispersion is observed.
If it exceeds 0.40 μm, there is a problem in the degree of coloring.

Further, the value of the saturation magnetization of the toner is 1
It is preferably in the range of 0 emu / g to 25 emu / g, more preferably 12 emu / g to 22 emu / g.
Good range. Here, the value of the saturation magnetization is 10 emu / g.
When it is less than 25, the effect of improving the background fogging by the magnetic bias effect is low, and when it is more than 25 emu / g, the magnetic bias effect is too large, the developing ability is extremely lowered, and a defect in image density is observed.

Still further, the binder resin is mainly a polyester resin, and the value of the molecular weight distribution by GPC determined by the THF soluble component of the toner has at least one peak between 1,000 and 10,000, It has been found that a toner having a half-width of the distribution of 15,000 or less in molecular weight and a THF insoluble content of 2 to 40% can be obtained by fixing the toner at a low temperature and free from the problem of background contamination.

Although the particle size of the toner of the present invention is not particularly limited, it is preferable that the volume average particle size is 2.5 to 10 μm in order to obtain high image quality with excellent reproducibility of fine lines. In particular, when a specific magnetic substance as used in the present invention is contained in the toner, the toner is easily crushed at the time of crushing during the production of the toner, and the particle size of the toner is more easily reduced. Therefore, high image quality is easily obtained.

Here, the toner volume average particle diameter can be measured by various methods. In the present invention, a Coulter counter TAII manufactured by Coulter Electronics Co., Ltd. of the United States is used.

Further, by using a two-component developer containing a toner and a magnetic carrier, the contact state between the developer and the toner is changed by changing the toner concentration of the developer on the developer carrier. In a developing device for changing a toner intake state of a developer on the developer carrier, the toner has at least a binder resin and a magnetic powder, and the surface of the magnetic powder is blackened by being coated with a colorant. It has been found that the above-mentioned drawbacks can be solved by an image forming method characterized by using a magnetic material having the above characteristics. In general, when a magnetic toner is used in two-component development, unlike a one-component development, when a magnetic toner having a high magnetization as used in a normal magnetic one-component developer is used, the developing ability is reduced due to the difference in the development. Is extremely reduced, and a desired image density cannot be obtained. In order to solve this problem, if a toner having a reduced magnetic substance content and reduced magnetization is used, a desired image density can be obtained even with two-component development. The blackness was reduced, and when a black pigment such as carbon black used in a conventional two-component toner was included in order to improve the blackness, the margin for background fog was reduced.

In particular, in the image forming method of the present invention which does not require the toner density detecting means, the density unevenness and the unevenness can be reduced as compared with the two-component development which has the conventional toner density detecting means and can maintain the proper toner density. It is required to improve the margin for occurrence of the ground cover.

The colorant used for the blackening is preferably a pigment and / or a dye. Further, since the coloring pigment is particularly carbon black, a black magnetic substance having a high jet blackness can be obtained, and there is an advantage that a desired black can be easily obtained by coating a small amount of the magnetic substance.
Further, by changing the toner concentration of the developer on the developer carrier using a two-component developer containing a toner and a magnetic carrier, the contact state between the developer and the toner is changed, and The toner used in the developing device that changes the toner intake state of the developer on the carrier has at least a binder resin and magnetic powder, and the surface of the magnetic powder is blackened by being coated with a colorant. It has been found that by using a magnetic material, it is possible to provide an image forming apparatus capable of solving the above-mentioned disadvantage.

As a specific example of the image forming apparatus of the present invention, a developer carrier having a magnetic field generating means therein for carrying and transporting a two-component developer containing a toner and a magnetic carrier; A first regulating member that regulates an amount of the developer carried and conveyed by the developer carrier; a developer accommodating section that accommodates the developer scraped off by the first regulating member; A toner storage unit that is adjacent to the developer storage unit and supplies toner to the developer carrier; and a contact state between the developer and the toner due to a change in toner concentration of the developer on the developer carrier. The developer accommodating portion to change the state of taking in the toner of the developer on the developer carrying member, wherein the developer accommodating portion is more developer than the first regulating member. Regulating section disposed on the upstream side in the conveyance direction The second regulating member regulates the passage of the increased amount of the developer when the toner concentration of the developer on the developer carrier increases and the layer thickness of the developer increases. Therefore, a gap with the developer carrier is set, and the developer in the developer accommodating portion is made of the same developer regardless of a change in the toner concentration of the developer on the developer carrier. When the developer moves within the storage section and the toner concentration of the developer on the developer carrying member reaches a predetermined toner concentration, the developer regulated to pass by the second regulating member is moved onto the developer carrying member. The toner used in a developing device that accumulates in a contact portion between the developer and the toner and stops the toner taking-in state of the developer on the developer carrier by blocking the contact portion with the developer is formed. At least a coating resin and magnetic powder, and the surface of the magnetic powder is Coated image forming apparatus using a magnetic material that has been blackened and the like.

The improvement of the density unevenness in the image apparatus is as follows.
This is to make the toner easy to move in the lateral direction. The larger the binding force on the toner constrained by the magnetic force on the developing sleeve, the more difficult it is for the toner to move and the density unevenness was more remarkable. Therefore, the lower the binding force to the toner, the better, and it is necessary to set the magnetic force of the toner itself within a specific range in order to achieve both background fogging suppression and density unevenness by a magnetic bias. However, in order to control the magnetic force of the toner, the amount of the magnetic substance contained in the toner may be controlled. However, when the amount of the magnetic substance is lower than a level generally called magnetic toner, the coloring power is reduced. In addition, when the coloring power was supplemented by incorporating carbon black, the ground fogging margin was reduced as described above. Here, by including in the toner a magnetic material whose surface is blackened by being coated with a colorant, a desired degree of coloring can be obtained even when only a small amount of magnetic material is used, and both the density unevenness and the background fog can be achieved. Found that he could do well.

In the image forming apparatus, the toner contains a magnetic material in an amount of 10 to 40% by weight, more preferably 1 to 40% by weight.
It has been found that the above disadvantage can be solved by containing 5 to 25 wt%. Here, the amount of the magnetic material is 10 wt.
%, The effect of improving the background fogging due to the magnetic bias effect is low, and if it is more than 40 wt%, the magnetic bias effect is too large, the developing ability is extremely reduced, and a defect in image density is observed. .

In the image forming apparatus, the colorant used for the blackening is preferably a pigment and / or a dye.

Further, in particular, when the coloring pigment is carbon black, a black magnetic substance having a high jet blackness can be obtained, and a desired black color can be easily obtained by coating a small amount of the magnetic substance. there were.

Further, it has been found that in the image forming apparatus, when the magnetic powder contains a magnetic substance coated with carbon black, more preferably 10 to 30% by weight, the above-mentioned disadvantage can be solved.

Further, in the image forming apparatus, when the toner contains carbon black inside, the content of carbon black needs to be 6 wt% or less. Here, the carbon black content is 6
When the amount is more than wt%, the occurrence of ground fogging due to the carbon black content is observed, and the smaller the amount, the better the ground fogging. At most, 6 wt% is the limit value. It was good. More preferably, it is not contained.

In the image forming apparatus, when the average particle diameter of the magnetic particles is 0.20 to 0.40 μm, the dispersibility of the magnetic substance in the resin is appropriately dispersed, and the black colorant Can be obtained as a substitute for carbon black. Here, when the thickness is less than 0.2 μm, aggregation of the magnetic material in the resin is more likely to occur, and ground fogging or the like due to poor dispersion is observed. When the thickness is more than 0.4 μm, there is a problem in the degree of coloring. was there.

Further, in the image forming apparatus, the value of the saturation magnetization of the toner is 10 emu / g to 25 emu / g.
g, more preferably 12e
The range of mu / g to 22 emu / g is good. Here, when the value of the saturation magnetization is less than 10 emu / g, the effect of improving the ground fogging by the magnetic bias effect is low, and when the value is more than 25 emu / g, the magnetic bias effect is too large and the developing ability is extremely reduced. A defect was observed in terms of density.

Further, in the image forming apparatus, the binder resin is mainly a polyester resin, and the TH
The value of the molecular weight distribution by GPC determined from the F-soluble component has at least one peak between 1,000 and 10,000, and the half width of the distribution is 15,000 or less,
It has been found that when the toner contains 2 to 40% of a THF-insoluble component, a toner which can be fixed at a low temperature and has no problem of background stain can be obtained.

Further, in the image forming apparatus, the particle size of the toner is not particularly limited, but in order to obtain high image quality excellent in fine line reproducibility and the like, the volume average particle size is 2.5%.
It is preferably from 10 to 10 μm. In particular, when a specific magnetic substance as used in the present invention is contained in the toner, the toner is easily crushed at the time of crushing during the production of the toner, and the particle size of the toner is more easily reduced. Therefore, high image quality is easily obtained.

GPC (gel permeation chromatography) is measured as follows. Stabilizing the column in a heat chamber at 40 ° C., flowing THF as a solvent through the column at this temperature at a flow rate of 1 ml per minute,
The measurement is performed by injecting 50 to 200 μl of a THF sample solution of a resin prepared to have a sample concentration of 0.05 to 0.6% by weight. In measuring the molecular weight of the sample, the molecular weight distribution of the sample was calculated from the relationship between the logarithmic value of a calibration curve prepared from several types of monodisperse polystyrene standard samples and the count number. As standard polystyrene samples for creating calibration curves,
For example, Pressure Chemical Co. Or, the molecular weight of Toyo Soda Kogyo KK is 6 × 10 ² ,
1 × 10 ³ , 4 × 10 ³ , 1.75 × 10 ⁴ , 5.1 × 1
^{0 4, 1.1 × 10 5,} 3.9 × 10 5, 8.6 × 10 5,
It is suitable to use 2 × 10 ⁶ and 4.48 × 10 ⁶ , and to use at least about 10 standard polystyrene samples. An RI (refractive index) detector is used as the detector.

The THF insoluble content is measured as follows.
About 1.0 g of the binder resin is weighed, about 50 g of THF is added thereto, and the mixture is allowed to stand at 20 ° C. for 24 hours. This is first separated by centrifugation and filtered at room temperature using JIS standard (P3801) 5 type C quantitative filter paper. Subsequently, the amount of filter paper residue (insoluble matter) was measured, and the ratio of the used toner to the filter paper residue (% by weight) was measured.
Is calculated. It should be noted that when the toner is used, T
When measuring the HF insoluble content, about 1.0 g of the toner is weighed and the same method as that for the binder resin is used. However, since solid matter such as pigment is present in the filter paper residue, it is separately analyzed by thermal analysis. Ask. The Tg of the binder resin is Rigaku T
It is measured by HRMOFLEX TG8110 at a temperature rising rate of 10 ° C./min. The softening point of the binder resin was determined by using an elevated flow tester CFT-500 (manufactured by Shimadzu Corporation), a die diameter of 1 mm, a pressure of 20 kg / cm ² , and a heating rate of 6 ° C./m.
It is measured at a temperature corresponding to 1/2 from the outflow start point to the outflow end point when a 1 cm ² sample is melted out under the condition of in.

Next, the materials used for the toner of the present invention will be described in detail. Examples of the binder resin used in the present invention include homopolymers of styrene such as polystyrene, poly p-chlorostyrene and polyvinyltoluene and substituted products thereof; styrene-p-chlorostyrene copolymer, styrene-propylene copolymer , Styrene-vinyl toluene copolymer, styrene-vinyl naphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer,
Styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene- Acrylonitrile copolymer, styrene-
Vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene- Styrene-based copolymers such as a maleic acid copolymer and a styrene-maleic acid ester copolymer are exemplified.

Further, the following resins can be mixed and used. Polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane, polyamide, epoxy resin, polyvinyl butyral, polyacrylic resin, rosin, modified rosin, terpene resin, phenol resin, aliphatic Or an alicyclic hydrocarbon resin, an aromatic petroleum resin, chlorinated paraffin, paraffin wax and the like.

Further, as the binder resin particularly suitable for pressure fixing, the following can be mentioned, and they can be used in combination. Polyolefin (low molecular weight polyethylene, low molecular weight polypropylene, polyethylene oxide polytetrafluoroethylene, etc.), epoxy resin, polyester resin, styrene-butadiene copolymer (monomer ratio 5-30: 95-7)
0), olefin copolymer (ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, ethylene-methacrylic acid copolymer, ethylene-methacrylic acid ester copolymer, ethylene-vinyl chloride copolymer, Ethylene-vinyl acetate copolymer, ionomer resin), polyvinyl pyrrolidone, methyl vinyl ether-maleic anhydride copolymer, maleic acid-modified phenol resin, phenol-modified terpene resin, and the like.

The method for producing these resins is not particularly limited, and any of bulk polymerization, solution polymerization, emulsion polymerization, and suspension polymerization can be used. Further, the glass transition temperature Tg of the resin is preferably 55 ° C. or more, more preferably 60 ° C. or more, from the viewpoint of heat preservability.

The magnetic material contained in the magnetic toner of the present invention includes iron oxide such as magnetite, hematite, and ferrite; metals such as iron, cobalt, and nickel; and aluminum, cobalt, copper, lead, and the like of these metals.
Magnesium, tin, zinc, antimony, beryllium,
Examples include alloys of metals such as bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, and vanadium, and mixtures thereof. In particular, magnetite is preferred in terms of magnetic properties. In the present invention, those obtained by coating the surface of these magnetic materials with a coloring agent are used. Here, the surface treatment with the coloring agent may be performed by using a mixer or the like for the magnetic substance, a method of immobilizing the colorant on the surface of the magnetic substance by a high-speed air impact method, a dry mechanochemical method, or a polysiloxane such as a paste. Is used, but the method is not limited thereto. The amount of carbon to be carbon-treated on the surface of the magnetic material is 5 to 20 wt.
%, More preferably 8 to 15% by weight. In particular, the shape of the magnetic material used is more preferably spherical. In addition, the average particle diameter was calculated | required by the average value of 50 actually measured at random from the scanning electron microscope photograph.

As the colorant used for coating the surface of the magnetic material of the present invention, for example, carbon black, lamp black,
A dye / pigment / compound that produces black by using several dyes and pigments, such as black dyes such as iron black, aniline black, graphite and fullerene, and any conventionally known black dye / pigment alone or mixed However, carbon black is most advantageous in terms of blackness.
Further, in consideration of the color of the magnetic substance, a colorant that makes the reddish color black by a complementary color, for example, a blue dye such as aniline blue or phthalocyanine blue may be used. The blackness of the toner using the blackened magnetic material of the present invention is expressed by the color space L ^* ab value, but the upper limit of the L ^* value is 2
4.0, preferably 23.0 or less, more preferably 21.0 or less, and the a value and the b value are each preferably ± 1.5 or less, more preferably ± 1.0 or less. . L
^{* If the} value exceeds 24.0, the lightness increases and the blackness decreases. For the a value and the b value, ± 1.5
If it is larger than the above, the color space will be in a direction away from black in the color space, and the degree of blackness will be reduced. Here, the measurement of the L ^* ab value was obtained by measuring a solid image formed on paper using X-Rite 938 manufactured by X-Rite.

As the colorant used in the toner of the present invention,
For example, dyeing such as carbon black, lamp black, iron black, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa Yellow G, rhodamine 6C lake, chaco oil blue, chrome yellow, quinacridone, benzidine yellow, rose bengal, and triallylmethane dyes Any conventionally known dyes and pigments such as pigments can be used alone or in combination, and can be used as a black toner or a full-color toner. The amount of these colorants to be used is generally 1 to 30% by weight, preferably 3 to 20% by weight, based on the toner resin component.

In the present invention, as the release agent used for the toner, any known release agent can be used. In particular, it is preferable to use carbauba wax, montan wax and rice oxide wax which are free fatty acids alone or in combination. it can.

The carnauba wax is preferably a microcrystalline wax having an acid value of 5 or less and a particle diameter of 1 μm or less when dispersed in a toner binder. The montan wax generally refers to a montan-based wax refined from a mineral, and is preferably a microcrystal 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. The use amount of these release agents is 1 to 20 parts by weight, preferably 3 to 10 parts by weight, based on the toner resin component.

The toner of the present invention can contain a charge controlling agent, a fluidity improving agent, and the like, if necessary. Further, as the charge control agent contained in the toner of the present invention,
All conventionally known ones can be used. Examples of positive charge control agents include nigrosine, basic dyes, lake dyes of basic dyes, quaternary ammonium salt compounds, and the like.As negative charge control agents, metal salts of monoazo dyes, salicylic acid,
Naphthoic acid, a metal complex of dicarboxylic acid, and the like.

As the hydrophobic inorganic fine powder used in the present invention, any known one can be used.
Hydrophobic silica fine powder, hydrophobic titanium fine powder and the like are preferable. As the hydrophobic silica particles used in the present invention, all known silica particles can be used. Examples of hydrophobizing agents such as silane coupling agents, silicone varnishes, silicone oils, organosilicon compounds, and these substances having a functional group include hexamethyldisilazane, hexamethylenedisilazane, trimethylsilane, and trimethylchlorosilane. , Trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, benzyldimethylchlorosilane, chloromethyldimethylchlorosilane,
Dichlorodimethylsilane, triorganosilylmercaptan, trimethylsilylmercaptan, vinyldimethylacetoxysilane, dimethylethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, aminopropyltrimethoxysilane, dipropylaminopropyltrimethoxysilane, dibutylaminopropyltrimethoxysilane , Dibutylaminopropylmethyldimethoxysilane, trimethoxysilyl-γ-propylphenylamine and the like. Silicone oils include methyl silicone oil, dimethyl silicone oil, phenyl methyl silicone oil, chlorophenyl methyl silicone oil, alkyl-modified silicone oil, fatty acid-modified silicone oil, amino-modified silicone oil,
And polyoxyalkyl-modified silicone oils. These are used in one kind or in a mixture of two or more kinds. In the above processes, a single process or various processes may be used in combination.

As the hydrophobic titanium particles used in the present invention, all known ones can be used. Examples of the surface treatment agent include various silicone oils such as methyl hydrogen polysiloxane, dimethyl polysiloxane, and methylphenyl polysiloxane, methyl trimethoxy silane, ethyl trimethoxy silane, hexyl trimethoxy silane,
Various alkylsilanes such as octyltrimethoxysilane, decyltrimethoxysilane, octadecyltrimethoxysilane, dimethyldimethoxysilane, octyltriethoxysilane, and n-octadecyldimethyl (3- (trimethoxysilyl) propyl) ammonium chloride Various fluoroalkylsilanes such as trimethoxysilane and heptadecafluorodecyltrimethoxysilane, especially silane-based, titanium-based, and aluminum represented by silane coupling agents such as vinyltrimethoxysilane and γ-aminopropyltrimethoxysilane Any metal-based coupling agent such as a metal-based, alumina-zirconia-based, etc. can be used, and two or more of these are mixed.

Further, the toner of the present invention may optionally contain additives. Examples of the additive include a lubricant such as Teflon (registered trademark) and zinc stearate, or a polishing agent such as cerium oxide and silicon carbide; a fluidity imparting agent such as colloidal silica and aluminum oxide; a caking inhibitor; Examples include a conductivity-imparting agent such as black and tin oxide, and a fixing aid such as low-molecular-weight polyolefin.

The toner of the present invention can be used as a one-component toner or a two-component toner, and can also be used as a mono-black toner or a full-color black toner.

The carrier core particles used when the toner of the present invention is used as a two-component developer include a magnetic core particle substantially consisting only of a magnetic material such as magnetic ferrite and a large number of magnetic fine particles. It is divided into the case of magnetic material-dispersed resin core particles dispersed in a resin.
In the case of the magnetic material core particles, as the magnetic material forming the core particles, magnetic metals such as iron, nickel and cobalt and alloys thereof, or alloys containing rare earth elements; hematite, magnetite, manganese-zinc ferrite Soft ferrites such as nickel-zinc ferrite, manganese-magnesium ferrite, and lithium ferrite; iron-based oxides such as copper-zinc ferrite; and mixtures thereof.

Further, other iron-based alloys, for example, iron-silicon-based alloys, iron-aluminum-based alloys, iron-silicon-aluminum-based alloys, permalloy alloys and the like can be used. In the present invention, preferably, magnetic ferrite core particles, wherein the ferrite particles are the periodic table IA,
IIA, IIIA, IVA, VA, VIA, IB, IIB, IIIB,
Magnetic particles containing at least one element selected from the group consisting of IVB, VB, VIB, VIIB, and VIIIB and containing less than 1% by weight of other elements can be used.

The magnetic core particles used in the present invention can be produced by a production method such as a sintering method or an atomizing method. By controlling the sintering temperature, heating rate, heating holding time, and the like, magnetic core particles having predetermined magnetic properties can be manufactured.

As the specific resistance of the magnetic core particles used in the present invention, any one can be used as long as it satisfies the desired magnetic properties, and a specific resistance of 10 ⁵ Ω · cm to ^{10 10} Ω · cm can be used. Ferrite particles having the following or magnetite particles are preferably used.

In the case of the magnetic material-dispersed resin core particles, examples of the magnetic material constituting the magnetic fine particles to be dispersed in the resin include alloys or compounds of ferromagnetic metals such as iron, cobalt and nickel.

The resin powder that can be coated on the carrier core particles used when the toner of the present invention is used as a two-component developer includes a styrene-acryl copolymer,
Silicone resin, maleic acid resin, fluorine resin, polyester resin, epoxy resin and the like are available. In the case of a styrene-acrylic copolymer, those having a styrene content of 30 to 90% by weight are preferred. In this case, the styrene content is 30
If the amount is less than 90% by weight, the developing characteristics are low. If the amount is more than 90% by weight, the coating film becomes hard and easily peels off, shortening the life of the carrier.

Further, the resin coating of the carrier in the present invention 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 resin.

Regardless of whether the toner of the present invention is used as a one-component developer or a two-component developer, the toner is filled in a container, and the container filled with the toner is distributed separately from the image forming apparatus. Generally, a user mounts an image on an image forming apparatus to form an image. 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 and a printer.

[0059]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described more specifically with reference to the following examples, but the present invention is not limited thereto. Note that the developing device is M
A modified MF-200 equipped with the F-250 and the apparatus of FIGS. 1 and 2 shown in the above configuration was used. All parts are parts by weight. Table 1 shows the results of averaging the evaluation results at the start and after 140,000 sheets of each example based on the following evaluation.

(Fog) Output in A3 size using a white original, and measure the image density at arbitrary six positions of the image using a Macbeth reflection densitometer. Performed in The state where there is no background fogging is a value equivalent to the reflection density of the paper, and the larger the value, the worse the ground fogging result. Good ◎: Very good, ○: Good, □: Normal, △: Bad,
×: Very bad evil

(Image Density Unevenness) The degree of occurrence of image density unevenness (history of the immediately preceding image) after continuously outputting 15 sheets of A4 size using a full-tone halftone chart is determined in five steps according to the following criteria. Performed in Good ◎: Very good, ○: Good, □: Normal, △: Bad,
×: Very bad evil

(Solid Uniformity (Image Density)) An image is output in A3 size using an A3 size chart having six solid portions in front, rear, left and right, and the positions of six solid portions of the image are output. Was measured with a Macbeth reflection densitometer, and the ID deviation was evaluated in five steps according to the following criteria. Good ◎: Very good, ○: Good, □: Normal, △: Bad,
×: Very bad evil

(Fine Line Reproducibility) An image evaluation test was carried out for each developer, and the fine line reproducibility was evaluated in five steps according to the following criteria. Excellent: ◎, Good: ○, □: Normal, △: Bad, ×: Worst

(Evaluation of Fixing Property) A copying machine MF-2 manufactured by Ricoh Co., Ltd. using a Teflon roller as a fixing roller.
Using a modified apparatus of the fixing unit 00, Ricoh type 6200 paper was set therein and a copying test was performed. By changing the fixing temperature, the cold offset temperature (fixing lower limit temperature) and the hot offset temperature (hot offset resistance temperature) were determined. The minimum fixing temperature of the conventional low-temperature fixing toner is about 140 to 150 ° C. The evaluation conditions for the low-temperature fixing are as follows: the linear velocity of the paper feed is 120 to 150 mm / sec;
Evaluation conditions of a surface pressure of 1.2 kgf / cm ² , a nip width of 3 mm, and a high-temperature offset are as follows.
c, the surface pressure was set to 2.0 kgf / cm ² , and the nip width was set to 4.5 mm. The cold offset occurrence temperature and the high temperature offset occurrence temperature were determined as follows. (Low temperature fixability) good ◎: less than 130 ° C., ○: 130 to 140 ° C., □:
140 to 150 ° C, Δ: 150 to 160 ° C, ×: 160
℃ or more bad (hot offset) good ◎: 201 ° C. or more, ○: 200 to 191 ° C., □: 1
90 to 181 ° C, Δ: 180 to 171 ° C, ×: 170 ° C
The following five steps were performed.

[0065]

[Table 1]

FIG. 1 is a schematic structural view of a main part of a developing device of an image forming apparatus employing an embodiment of the developing device of the present invention.
In an actual embodiment, the developing device is a copying machine MF-2 manufactured by Ricoh.
00 was incorporated into a modified machine and evaluated. The details will be described below. The developing device (13) disposed on the side of the photosensitive drum (1) as a latent image carrier includes a support case (14) and a developing sleeve (1) as a developer carrier.
5) It mainly comprises a developer accommodating member (16), a first doctor blade (17) as a developer regulating member, and the like.

The support case (14) having an opening on the photosensitive drum (1) side forms a toner hopper (19) as a toner accommodating portion for accommodating the toner (18) therein. Near the photosensitive drum (1) side of the toner hopper (19), a developer accommodating section (16) for accommodating a developer (22) comprising a toner (18) and a carrier as magnetic particles.
The developer accommodating member (16) forming (a) is provided integrally with the support case (14). Further, the support case (14) located below the developer accommodating member (16) is formed with a protruding portion (14a) having an opposing surface (14b). The space between the opposed surface (14b) forms a toner supply opening (20) for supplying the toner (18).

Inside the toner hopper (19), there is provided a toner agitator (21) as toner supply means which is rotated by a driving means (not shown). The toner agitator (21) sends the toner (18) in the toner hopper (19) toward the toner supply opening (20) while stirring. The toner hopper (19)
A toner end detecting means (14c) for detecting when the amount of the toner (18) in the toner hopper (19) becomes small is disposed on the side facing the photosensitive drum (1). I have.

The photosensitive drum (1) and the toner hopper (1)
A developing sleeve (15) is provided in the space between the developing sleeve (9). A developing sleeve (15), which is rotationally driven by a driving unit (not shown) in the direction of the arrow in the figure, has a magnet (not shown) as a magnetic field generating unit, disposed inside the developing sleeve (15) at a fixed position relative to the developing device (13). have. A first doctor blade (17) is provided on a side of the developer accommodating member (16) opposite to a side attached to the support case (14).
Are attached integrally. The first doctor blade (17) is arranged with a certain gap kept between its tip and the outer peripheral surface of the developing sleeve (15).

A second doctor blade (23) as a regulating member is provided at a portion of the developer containing member (16) located near the toner supply opening (20).
The second doctor blade (23) is formed of a layer of the developer (22) formed on the surface of the developing sleeve (15) such that its free end keeps a constant gap with respect to the outer peripheral surface of the developing sleeve (15). The base end is integrally attached to the developer accommodating member (16) in a direction that obstructs the flow, that is, with the free end facing the center of the developing sleeve (15). The developer accommodating portion (16a) is configured to have a sufficient space for circulating the developer (22) within a range where the magnetic force of the developing sleeve (15) can reach.

The facing surface (14b) is formed over a predetermined length so as to be inclined downward from the toner hopper (19) toward the developing sleeve (15). Accordingly, when vibration, uneven magnetic force distribution of a magnet (not shown) provided inside the developing sleeve (15), a partial increase in toner density in the developer (22), and the like occur, the second doctor blade ( 23) and the developing sleeve (1)
Even if the carrier in the developer accommodating portion (16a) falls from between the peripheral surface of (5) and the carrier, the fallen carrier will not move.
It is received by b), moves to the developing sleeve (15) side, is magnetically attached to the developing sleeve (15) by magnetic force, and is again supplied into the developer accommodating portion (16a). As a result, it is possible to prevent a decrease in the amount of carriers in the developer accommodating portion (16a), and to prevent image density unevenness in the axial direction of the developing sleeve (15) during image formation. The inclination angle (α) of the facing surface (14b) is about 5 °,
The predetermined length (l) is preferably 2 to 20.
mm, more preferably about 3 to 10 mm.

With the above configuration, the toner hopper (19)
The toner (18) sent out from the inside by the toner agitator (21) passes through the toner supply opening (20) and the developer (22) carried on the developing sleeve (15).
And transported to the developer accommodating section (16a). Then, the developer (22) in the developer accommodating portion (16a) is carried by the developing sleeve (15) and transported to a position facing the outer peripheral surface of the photosensitive drum (1), and only the toner (18) is transferred. The toner image is formed on the photosensitive drum (1) by being electrostatically coupled with the electrostatic latent image formed on the photosensitive drum (1).

Here, the behavior of the developer (22) during the formation of the toner image will be described. When a starter consisting of only the magnetic carrier (22a) is set in the developing device (13), as shown in FIG. 2, the magnetic carrier (22a) is magnetically attached to the surface of the developing sleeve (15) and contains the developer. It is divided into those housed in the section (16a). The magnetic carrier (22) accommodated in the developer accommodating portion (16a)
(a) is circulated in the direction of the arrow (b) by magnetic force from inside the developing sleeve (15) as the developing sleeve (15) rotates in the direction of the arrow (a). An interface (X) is formed at the boundary between the surface of the magnetic carrier (22a) magnetically attached to the surface of the developing sleeve (15) and the surface of the magnetic carrier (22a) moving in the developer accommodating portion (16a). It is formed.

Next, when the toner (18) is set in the toner hopper (19), the toner supply opening (20)
The toner (18) is supplied to the magnetic carrier (22a) carried on the developing sleeve (15). Therefore, the developing sleeve (15) carries the developer (22) which is a mixture of the toner (18) and the magnetic carrier (22a).

In the developer accommodating portion (16a), the developing sleeve (1) is provided due to the presence of the accommodated developer (22).
A force is applied to the developer (22) conveyed by 5) to stop the conveyance. When the toner (18) present on the surface of the developer (22) carried on the developing sleeve (15) is transported to the interface (X), friction between the developer (22) near the interface (X) is generated. The force decreases and the transport force of the developer (22) near the interface (X) decreases, thereby causing the developer (22) near the interface (X) to decrease.
Is reduced.

On the other hand, from the junction (Y), the developing sleeve (1)
In the developer (22) on the upstream side in the rotation direction of 5), the developing sleeve (1) as in the above-mentioned developer accommodating portion (16a) is provided.
Since no force is applied to the developer (22) conveyed by 5) to stop the conveyance, the developer (22) conveyed to the junction (Y) and the interface (X) are conveyed. The balance of the transport amount with the developer (22) to be carried out is lost, and a collision state of the developer (22) occurs, the position of the junction (Y) rises, and the developer (22) including the interface (X) is raised. ) Increases the layer thickness. Further, the layer thickness of the developer (22) passing through the first doctor blade (17) also gradually increases, and the increased developer (22) is scraped off by the second doctor blade (23).

When the developer (22) that has passed through the first doctor blade (17) reaches a predetermined toner concentration, as shown in FIG. 2, the second doctor blade (23).
Developer (22) that has been layered by being scraped off
Closes the toner supply opening (20), and the intake of the toner (18) ends in this state. At this time, in the developer accommodating portion (16a), the bulk of the developer (22) is increased due to the increase in toner concentration, and the space in the developer accommodating portion (16a) is narrowed. The moving speed at which the agent (22) circulates in the direction of the arrow (b) in the figure also decreases.

In the layer of the developer (22) formed so as to cover the toner supply opening (20), the developer (22) scraped off by the second doctor blade (23).
Is moved and received on the facing surface (14b), but the facing surface (14b) is inclined downward at an angle (α) toward the developing sleeve (15) side and has a predetermined length (1). Therefore, it is possible to prevent the developer (22) from dropping to the toner hopper (19) due to the movement of the layer of the developer (22), and to always keep the amount of the developer (22) constant. Therefore, it is possible to always self-control the toner supply to be constant.

[0079]

EXAMPLE Next, an example of manufacturing a carbon-treated magnetic material used in this example and the like will be described. This can be obtained by known surface treatment means, but is not limited thereto.

(Production Example 1 of Blackened Magnetic Material) Carbon black is added to magnetite particles MTS-305 manufactured by Toda Kogyo Co., Ltd. using an 8 wt% mechano mill (manufactured by Okada Seiko) or mechano fusion system (manufactured by Hosokawa Micron). The black magnetic material 1 was obtained by fixing the particles on the surface of the magnetite particles.

(Production Example 2 of Blackened Magnetic Material) An 8 wt% aniline black is added to magnetite particles MTS-305 manufactured by Toda Kogyo Co., Ltd. using a mechano mill (manufactured by Okada Seiko Co., Ltd.) or Mechano Fusion System (manufactured by Hosokawa Micron Co., Ltd.). The black magnetic material 2 was obtained by fixing the particles on the surface of the magnetite particles.

Next, a production example of a carrier having a silicone resin used in the present embodiment and the like in the coating layer will be described. This can be performed by known means. (Carrier production example 1) Composition of coating layer forming liquid Silicon resin solution (SR2411 manufactured by Toray Silicone Co., Ltd.) 100 parts Carbon black (# 44 manufactured by Mitsubishi Kasei Kogyo Co., Ltd.) 4 parts Toluene 100 parts The above formulation was dispersed with a homomixer for 30 minutes. Thus, a coating layer forming liquid was prepared. This coating layer forming solution was used to obtain a carrier A in which a coating layer was formed on the surface of 1,000 parts by weight of spherical ferrite having an average particle size of 80 μm using a fluidized bed type coating apparatus.

Example 1 85 parts of a polyester resin (weight average molecular weight: 104,100, Tg: 66 ° C., chloroform insoluble content: 5%, molecular weight peak: 15,000) Styrene methyl acrylate: 15 parts Carbon-treated magnetic material 1 (average diameter: 0.1%) 23 μm) 30 parts (21.9 wt%) carbon black 3 parts low molecular weight polypropylene 5 parts metal-containing azo compound 2 parts After sufficiently stirring and mixing the mixture of the above composition in a Henschel mixer, the mixture is roll-milled at a temperature of 130 to 140 ° C. 3
After heating and melting for 0 minutes and cooling to room temperature, the obtained kneaded material was pulverized and classified by a jet mill, a mechanical pulverizer, or an air classifier to obtain a toner base having a volume average diameter of 9.0 μm. 0.7 wt% of a predetermined hydrophobic silica was added to and mixed with the obtained toner base to obtain a final toner. 4.0 parts of this toner was mixed with 96.0 parts of the above carrier A by a ball mill to obtain a developer. A copying experiment was performed using MF-250 as the developer. At this time, the saturation magnetization of the toner is 15.2 emu / g, the main peak of the molecular weight distribution is 10,000, and the half width of the toner molecular weight distribution is 30,000.
0, THF insoluble content was 0%.

(Example 2) The toner volume average diameter was 12.0
A toner was obtained in the same manner as in Example 1 except that the amount of the hydrophobic silica was 0.5 μm and the amount of the hydrophobic silica was 0.5 wt%.

(Example 3) The toner volume average diameter was set to 7.0 μm.
m, except that the amount of hydrophobic silica added was 0.9 wt%.
The same toner as in Example 1 was obtained.

(Comparative Example 1) The same test as in Example 1 was conducted except that the carbon-treated magnetic material 1 in Example 1 was changed to an untreated carbon material.

(Comparative Example 2) The same test as in Example 1 was performed except that the carbon-treated magnetic material 1 in Example 1 was contained in an amount of 5 wt% and carbon black in an amount of 10 wt%. The saturation magnetization of the toner at this time was 5.8 emu / g.

(Comparative Example 3) The same test as in Example 1 was performed except that the carbon-treated magnetic material 1 in Example 1 was contained at 50 wt%. The saturation magnetization of the toner at this time was 41.8 emu / g.

(Embodiment 4) The amount of the magnetic material of the embodiment 1 was 36 w
The same test as in Example 1 was performed, except that the test was increased to t%. The saturation magnetization of the toner at this time is 31.2 em
u / g.

(Example 5) The particle size of the magnetic material of Example 1 was set to 0.
The same test as in Example 1 was performed except that the thickness was changed to 13 μm. At this time, the saturation magnetization of the toner is 16.2e
mu / g.

Example 6 The particle size of the magnetic material of Example 1 was set to 0.
The same test as in Example 1 was performed except that the thickness was changed to 35 μm. At this time, the saturation magnetization of the toner is 15.0 e.
mu / g.

Example 7 100 parts of polyester resin (weight average molecular weight 5,700, Tg 63 ° C., THF insoluble content 22%) Low molecular weight polypropylene 5 parts (Viscol 550P: manufactured by Sanyo Chemical Co., Ltd.) Black magnetic material 1 (average diameter) 0.23 μm) 25 parts (18.8 wt%) carbon black (# 44: manufactured by Mitsubishi Kasei Co., Ltd.) 2 parts Metal-containing azo compound 1 part After sufficiently stirring and mixing the mixture having the above composition in a Henschel mixer, the mixture was mixed with a roll mill. About 3 at 140 ° C
After heating and melting for 0 minutes and cooling to room temperature, the obtained kneaded material was pulverized and classified by a jet mill, a mechanical pulverizer, or an air classifier to obtain a toner base having a volume average particle size of about 9 μm. 0.7 wt% of a predetermined hydrophobic silica was added to and mixed with the obtained toner base to obtain a final toner. 4.0 parts of this toner was mixed with 96.0 parts of the above carrier A by a ball mill to obtain a developer. The same test as in Example 1 was performed using this developer. The saturation magnetization of the toner at this time is 13.6 emu / g, and the main peak of the molecular weight distribution is 7
900, half width of toner molecular weight distribution is 13,000, TH
The F-insoluble content was 18%.

Example 8 Toner 1 similar to Example 1
3.0 parts of the above carrier A and 87.0 parts of the carrier A were mixed by a ball mill to obtain a developer. Copying experiments were performed on this developer using a modified MF-200 equipped with the apparatus shown in FIGS.

Comparative Example 4 The same test as in Example 8 was performed except that the black magnetic material 1 in Example 8 was changed to a carbon untreated product.

Example 9 The same test as in Example 8 was conducted except that the content of carbon black in Example 8 was increased to 8 wt%. The saturation magnetization of the toner at this time was 12.3 emu / g.

(Embodiment 10) Black magnetic body 1 in Embodiment 8
Was carried out in the same manner as in Example 8, except that 5 wt% of carbon black and 10 wt% of carbon black were contained. The saturation magnetization of the toner at this time was 5.4 emu / g.

(Embodiment 11) Black magnetic body 1 in embodiment 8
Was carried out in the same manner as in Example 8, except that 50 wt% was contained. The saturation magnetization of the toner at this time is 4
It was 1.8 emu / g.

(Example 12) The same test as in Example 8 was conducted except that the toner in Example 8 except for the carbon black was used. The saturation magnetization of the toner at this time is 2
It was 1.9 emu / g.

(Embodiment 13) The amount of the magnetic material of the embodiment 8 was 38
The same test as in Example 8 was performed except that the amount was increased to wt%. The saturation magnetization of the toner at this time is 31.3 e.
mu / g.

(Example 14) The same test as in Example 8 was performed except that the particle diameter of the magnetic substance in Example 8 was changed to 0.13 µm. The saturation magnetization of the toner at this time was 13.8 emu / g.

Example 15 The same test as in Example 8 was performed except that the particle diameter of the magnetic material in Example 8 was changed to 0.35 μm. The saturation magnetization of the toner at this time was 13.2 emu / g.

(Example 16) A test similar to that of Example 8 was performed, except that the toner of Example 8 was changed to the following configuration. Polyester resin (A) 50 parts (weight average molecular weight 5,100, Tg 63 ° C, THF insoluble content 0%, softening point 145 ° C, molecular weight peak 4,100) Polyester resin (B) 50 parts (weight average molecular weight 6,200, Tg 61 ° C., THF insoluble content 30%, softening point 100 ° C., molecular weight peak 3,800) Oxidized rice wax 5 parts Black magnetic substance 2 (average diameter 0.25 μm) 30 parts (22.1 wt%) metal-containing azo compound 1 part After sufficiently stirring and mixing the mixture having the above composition in a Henschel mixer, the mixture was rolled at a temperature of 130 to 140 ° C. for about 3 hours.
After heating and melting for 0 minutes and cooling to room temperature, the obtained kneaded material was pulverized and classified by a jet mill, a mechanical pulverizer, or an air classifier to obtain a toner base having a volume average particle size of about 6.8 μm.
0.7 wt% of a predetermined hydrophobic silica is added to the obtained toner matrix.
% And mixed to obtain the final toner. 3. this toner
To 0 part, 96.0 parts of the above carrier A was mixed by a ball mill to obtain a developer. A test similar to that in Example 6 was performed using this developer. At this time, the saturation magnetization of the toner was 17.3 emu / g, the main peak of the molecular weight distribution was 6100, the half width of the toner molecular weight distribution was 10,000,
The THF insoluble content was 13%.

(Example 17) Black colorant 1 of Example 16
The same test as in Example 8 was conducted except that was changed to black colorant 2. The saturation magnetization of the toner at this time is 1
It was 7.1 emu / g.

[0104]

As is clear from the above description, the magnetic material whose surface has been blackened by coating with a coloring agent is contained in the toner within a predetermined range, so that the magnetic material can be grounded. It is possible to provide a toner with improved fog, and a toner used in a specific developing method in which the toner density can be easily adjusted with a simple configuration in which the toner supply can be constantly controlled to be constant. In addition, it is possible to provide an image forming method and an image forming apparatus with improved density unevenness and background fog over time by copying by incorporating a magnetic material whose surface is blackened by coating with a colorant. It has excellent effects.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of an image forming apparatus according to the present invention.

FIG. 2 is an example showing behavior of a developer when forming a toner image in an example of the image forming apparatus of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 latent image carrier (photosensitive drum) 13 developing device 14 support case 14a support case protrusion 14b support case facing surface 14c toner end sensor 15 developer carrier (development sleeve) 16 developer accommodating member 16a developer accommodating portion 17 First regulating member (first doctor blade) 18 Toner 19 Toner container (toner hopper) 20 Toner supply opening 21 Toner supplying means (toner agitator) 22 Developer 22a Magnetic carrier 23 Second regulating member (Second doctor) Blade) X Interface (Interface) Y Developer confluence a Developing sleeve rotation direction b Carrier circulation direction α Opposite surface inclination angle l Opposite surface length

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 15/08 115 G03G 9/08 331 504 361 507 15/08 507X (72) Inventor Masahide Yamashita Ota, Tokyo 1-3-6 Nakamagome-ku, Riku Co., Ltd. (72) Inventor Kazuto Watanabe 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (72) Keiko Shiraishi Nakamagome, Ota-ku, Tokyo 1-3-6, Ricoh Co., Ltd. (72) Inventor Mitsuteru Kato 1-3-6, Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd.

Claims (24)

[Claims] 1. A toner having at least a binder resin and magnetic powder, wherein the magnetic powder contains 10 to 40% by weight of a black magnetic material coated with a colorant. Electrophotographic toner. 2. The electrostatic image forming toner according to claim 1, wherein the colorant used for the blackening is a pigment and / or a dye. 3. The electrostatic image forming toner according to claim 2, wherein the color pigment is carbon black. 4. The electrostatic image forming toner according to claim 1, wherein the magnetic powder contains 10 to 30% by weight of a magnetic material coated with carbon black. 5. The electrostatic image forming apparatus according to claim 1, wherein when the toner contains garbon black, the content of carbon black is 6% by weight or less. For toner. 6. The magnetic particles having an average particle size of 0.20 to 0.20.
The toner for forming an electrostatic image according to claim 1, wherein the thickness of the toner is 0.40 μm. 7. The toner has a saturation magnetization of 10 to 25 e.
The toner for forming an electrostatic image according to any one of claims 1 to 6, wherein the toner is mu / g. 8. The binder resin is mainly a polyester resin, and a value of a molecular weight distribution by GPC determined by a THF-soluble component of the toner has at least one peak between 1,000 and 10,000, and The half width of the distribution is molecular weight 1
5,000 or less, and the toner has a THF insoluble content of 2 to 40
% Of any one of claims 1 to 7.
3. The toner for forming an electrostatic image according to item 1. 9. A toner having a volume average particle size of 2.5 to 10
9. The method according to claim 1, wherein the thickness is μm.
3. The toner for forming an electrostatic image according to item 1. 10. A two-component developer containing a toner and a magnetic carrier, wherein the contact state between the developer and the toner is changed by changing the toner concentration of the developer on a developer carrier. In a developing device for changing a toner take-up state of a developer on a developer carrier, the toner has at least a binder resin and a magnetic powder, and the surface of the magnetic powder is blackened by being coated with a colorant. An image forming method using a magnetic material. 11. The image forming method according to claim 10, wherein the colorant used for the blackening is a pigment and / or a dye. 12. The image forming method according to claim 11, wherein the color pigment is carbon black. 13. Using a two-component developer containing a toner and a magnetic carrier to change the contact state between the developer and the toner by changing the toner concentration of the developer on a developer carrier, The toner used in the developing device that changes the toner take-up state of the developer on the developer carrier has at least a binder resin and magnetic powder, and the surface of the magnetic powder is blackened by being coated with a colorant. An image forming apparatus using a magnetic material. 14. The image forming apparatus according to claim 13, wherein the content of the blackened magnetic material in the toner is 10 to 40 wt%. 15. The image forming apparatus according to claim 13, wherein the colorant used for the blackening is a pigment and / or a dye. 16. The image forming apparatus according to claim 15, wherein said color pigment is carbon black. 17. The image forming apparatus according to claim 13, wherein said magnetic powder contains 10 to 30 wt% of a magnetic material coated with carbon black. 18. The image forming apparatus according to claim 16, wherein when the toner contains garbon black, the content of garbon black is 6 wt% or less. 19. The magnetic particles having an average particle size of 0.20 to 0.20.
3. The method according to claim 1, wherein the thickness is 0.30 μm.
8. The electrostatic image forming apparatus according to any one of 8. 20. The toner having a saturation magnetization of 10 emu.
/ G to 25 emu / g.
20. The electrostatic image forming apparatus according to any one of items 3 to 19. 21. GPC determined by the THF-soluble content of the toner, wherein the binder resin is mainly a polyester resin.
Has at least one peak between 1,000 and 10,000, the half-width of the distribution is 15,000 or less, and the toner has a THF insoluble content of 2-4.
The electrostatic image forming apparatus according to any one of claims 13 to 20, wherein the content is 0%. 22. The toner has a volume average particle size of 2.5-1.
22. The image forming apparatus according to claim 13, wherein the thickness of the image forming apparatus is 0 [mu] m. 23. A toner container filled with the toner for forming an electrostatic image according to claim 1. Description: 24. An image forming apparatus equipped with the toner container according to claim 23.