JP4943243B2 - Electrophotographic developing carrier, carrier manufacturing method, developer, and image forming method - Google Patents

Description

  The present invention relates to a method for producing a carrier for developing an electrostatic latent image suitably used for electrophotography, electrostatic recording method, electrostatic printing method and the like, a carrier, a developer using the carrier, and the developer. The present invention relates to the image forming method used.

  The dry development method used in electrophotography forms a visible image by electrostatically attaching toner rubbed with a charging member to an electrostatic latent image. In such a dry development method, a so-called one-component development method having toner as a main component, glass beads, a magnetic carrier, or a carrier whose surface is coated with a resin and the toner are mixed. There is a so-called two-component development system to be used.

In the developer used in the two-component development system, minute toner particles are held on the surface of a relatively large core material by the electric force generated by friction between both particles, and this developer is close to the electrostatic latent image. Then, the toner particles overcome the binding force with the core material by the electric field formed by the electrostatic latent image, and are developed on the electrostatic latent image. The developer is repeatedly used while replenishing the toner consumed by the development.
For this reason, the core material must be triboelectrically charged with a desired polarity and a sufficient charge amount at all times during long-time use. However, collision between the particles, mechanical stirring in the particles and the developing device, or heat generated by them generates a so-called spent toner in which the toner is fused to the surface of the core material, and the charging characteristics of the core material decrease with use time. To do. As a result, the background of the image and toner scattering occur, so that the entire developer needs to be replaced.

  In order to prevent such spending, the life of the carrier is extended by coating the surface of the core material with a resin having a low surface energy, such as a fluororesin or a silicone resin. For example, a carrier coated with a room temperature curable silicone resin and a positively chargeable nitrogen resin (see Patent Document 1), a carrier coated with a coating material containing at least one modified silicone resin (see Patent Document 2), a room temperature curable silicone A carrier having a coating layer containing a resin and a styrene-acrylic resin (see Patent Document 3), a carrier in which the core particle surface is coated with two or more layers of silicone resin so that there is no adhesion between the layers (see Patent Document 4) ), A carrier in which silicone resin is applied in multiple layers on the core particle surface (see Patent Document 5), a carrier whose surface is coated with a silicon resin containing silicon carbide (see Patent Document 6), and exhibits a critical surface tension of 20 dyn / cm or less. A positively chargeable carrier coated with a material (see Patent Document 7) and coated with a coating material containing a fluorine alkyl acrylate. And a carrier, the developer comprising a toner containing a containing chromium azo dye (see Patent Document 8), and the like.

  Recently, in order to improve image quality, the toner tends to have a smaller particle size, and as a result, toner spent on the carrier is likely to occur. In addition, in conventional spray coating, it is difficult to uniformly wet the carrier surface with a coating material, and therefore it is difficult to produce a carrier having a coating film and a core material with a uniform film thickness and film quality. It has become. Furthermore, in the case of a full color toner, a resin with a low softening point is used in order to obtain a sufficient color tone. Therefore, the spent amount to the carrier is larger than that of the black toner, and the toner charge amount is reduced. Scattering and background contamination occur. As described above, in the full-color electrophotographic system, when the toner charge amount is lowered, there is a problem that the image density particularly in the highlight portion is easily changed and the high image quality cannot be maintained.

  In addition, in order to improve the durability of the carrier, a coating layer in which fine particles and a conductivity-imparting material are dispersed in a resin matrix of a low surface energy substance can be provided to control the spent resistance, film strength, and electrical characteristics. Although shown (see Patent Documents 9 to 11), since a dispersion liquid in which fine particles are added to an organic solvent is spray-coated at a high temperature, there is a problem that it is difficult to make the charge amount uniform due to aggregation of the fine particles and the like.

  Further, it has been shown that a coating layer formed by dispersing a conductive polymer substance in a resin is provided on the surface of the carrier core as a conductivity imparting material to control the electrical resistance of the carrier surface (see Patent Document 12). However, it is difficult to uniformly disperse the conductive polymer in the coating resin due to the compatibility problem between the resins, and the resistance has not been stabilized.

  Accordingly, a carrier having a coating layer on the surface of the core material, in which the conductive material is uniformly dispersed in the coating layer, having high adhesion between the core material and the coating layer, and a coating layer having a uniform thickness, and related technology However, there are not enough satisfactory products, and there are many problems to be improved in the conventional carrier manufacturing methods and carriers from the viewpoint of environmental load and resource saving. .

Japanese Patent Laid-Open No. 55-127469 Japanese Patent Laid-Open No. 55-157751 JP-A-56-140358 JP-A-57-96355 JP 57-96356 A JP 58-207054 A JP-A-61-1110161 JP-A-62-273576 JP-A-9-319161 JP-A-9-269614 Japanese Patent Laid-Open No. 10-186731 Japanese Patent No. 2626754

  An object of the present invention is to solve various problems in the prior art and achieve the following objects. That is, the present invention has a coating layer on the surface of the core material, and by containing the fibrous material in the coating layer, the toner chargeability, stability over time, etc. are good. A carrier for electrophotographic development having a coating layer with good adhesion and a uniform thickness, a method for producing the carrier, and there is no toner scattering, background contamination, or edge effect using the carrier, and an image with a high image density can be formed. An object is to provide a developer and an image forming method using the developer.

In order to solve the above-mentioned problems, the present inventors have conducted intensive studies. As a result, the coating layer contains a fibrous material, and the fibrous material is made of a conductive material. A carrier having high adhesiveness of the material, a coating layer having a uniform thickness, high mechanical strength, and excellent toner chargeability and stability over time can be obtained. It has been found that there can be obtained a developer capable of forming an image having a high image density without a background stain and an edge effect, and an image forming method using the developer.
That is, the above-described problem is (1) “in the carrier having a coating layer on the surface of the core material, the fibrous material is contained in the coating layer, and the fibrous material is selected from conductive polymers. At least one carrier , wherein the fibrous material is formed by an electrospinning method ",
(2) “The carrier according to the item ( 1 ) forms a coating layer on the core material surface coated with the fibrous material and a mixture of the core material and the fibrous material obtained in the above-described step. A carrier characterized by being manufactured through a process ",
(3) "The carrier manufacturing method according to ( 2 ), wherein the coating step coats a fibrous material by an electrospinning method",
(4) "Developer comprising the carrier described in the item ( 1 ) or (2) and a toner",
(5) “An electrostatic latent image forming step of forming an electrostatic latent image on the electrostatic latent image carrier, and developing the electrostatic latent image using the developer described in the item ( 4 )”. An image forming method comprising at least a developing step for forming a visible image, a transferring step for transferring the visible image to a recording medium, and a fixing step for fixing the transferred image transferred to the recording medium. To achieve.

  As will be apparent from the following detailed and specific invention, according to the present invention, the carrier particle has a coating layer on the surface of the core material, and the fibrous material is contained in the coating layer, so that the toner chargeability and stability over time are stabilized. And the like. The carrier for electrophotographic development having a coating layer of uniform thickness with good adhesion between the coating layer and the fibrous material, the method for producing the carrier, and the carrier, There are excellent effects that a developer capable of forming an image having a high image density without a background stain and an edge effect and an image forming method using the developer can be provided.

  The present invention is described in detail below.

[Coating layer]
The coating layer contains at least a coating resin, and further contains other components as necessary.

[Resin for coating]
The coating resin is not particularly limited and may be appropriately selected from known resins according to the purpose. Examples thereof include amino resins, polyvinyl resins, polystyrene resins, halogenated olefin resins, and polyesters. Resin, polycarbonate resin, polyethylene resin, polyvinyl fluoride resin, polyvinylidene fluoride resin, polytrifluoroethylene resin, polyhexafluoropropylene resin, copolymer of vinylidene fluoride and acrylic monomer, vinylidene fluoride and Copolymers with vinyl fluoride, fluoroterpolymers (triple fluoride (multiple) copolymer) such as terpolymers of tetrafluoroethylene, vinylidene fluoride and non-fluorinated monomers, silicone resins, etc. . These may be used individually by 1 type and may use 2 or more types together. Among these, a silicone resin is particularly preferable because of its high effect.

[Core]
There is no restriction | limiting in particular as said core material, According to the objective, it can select suitably from what is known as a two-component carrier for electrophotography, For example, a ferrite, magnetite, iron, nickel is mentioned suitably. In addition, in consideration of the environmental aspects that have advanced remarkably in recent years, if ferrite is used, for example, Mn ferrite, Mn-Mg ferrite, Mn-Mg-Sr ferrite, etc. should be used instead of conventional copper-zinc ferrite. Is preferred.
The core material preferably has a volume average particle size of 20 μm or more from the viewpoint of prevention of carrier adhesion (scattering) to the electrostatic latent image carrier, and is intended to prevent deterioration of image quality such as prevention of occurrence of carrier streaks. To 50 μm or less is preferable, and in particular, for recent high image quality, a volume average particle size of 20 to 50 μm is more preferable.
Here, the volume average particle diameter of the core material can be measured, for example, using “Microtrac particle size analyzer SRA” manufactured by Nikkiso Co., Ltd., with a range setting of 0.7 to 125 μm.

  When the obtained carrier is used as a two-component developer, it is preferable that LogR of the measured electric resistance is 7 to 16 Ω · cm. The electrical resistance can be appropriately selected according to the development process using a carrier, and when the LogR is less than 7 Ω · cm, the rising shape of the carrier brush (magnetic brush) held on the developer carrying member Becomes darker and becomes more conspicuous, and if LogR exceeds 16 Ω · cm, the density difference between the edge part and the solid part of the image or the density difference between the line image and the solid image may occur. In some cases, problems such as a decrease in developing ability due to charge-up and carrier development (carrier adhesion) on a non-image portion of a latent image may occur.

  Here, the electric resistance of the carrier is, for example, a value obtained from a current value and an applied voltage when a carrier is filled between two parallel electrodes and a potential difference is provided between the electrodes. Specifically, a container having electrodes arranged in parallel at an interval of 2 mm is filled with a carrier, and a direct current resistance at a potential difference of 50 V between both electrodes is measured by a 4329A High Resistance Meter manufactured by Yokogawa Hewlett-Packard Co., Ltd.

  Moreover, the thickness of the coating layer of the carrier is preferably set as appropriate so that the electric resistance falls within an appropriate range. However, since silicone has volume shrinkage during the condensation reaction, the coating layer becomes thicker as the thickness of the coating layer increases. There is a drawback that non-uniform reaction within the layer tends to occur. Therefore, the thickness of the coating layer is preferably 1.0 μm or less, and more preferably 0.02 to 0.8 μm. Here, the thickness of the coating layer can be measured by observing the cross section of the carrier using, for example, a transmission electron microscope (TEM).

[Fibrous material]
The “fibrous material” in the present invention is preferably a material having a fiber diameter of 1 nm to 1 μm and a length of 50 times or more with respect to the fiber diameter.

In addition, the fibrous material may have various cross-sectional shapes in the radial direction such as a circle, an ellipse, a flat shape, and a star shape, but a high aspect ratio is required to obtain smoothness with a small layer thickness. Those having a flat cross-section with The more complicated the shape of the fibrous material, the greater the specific surface area of the fibrous material. The greater the specific surface area of the fibrous material, the better the resistance control ability.
The fiber diameter of the fibrous material is not particularly limited, but is preferably 1 nm to 1 μm, more preferably 10 nm to 0.1 μm. When the fiber diameter of the fibrous material is within this range, the resistance control ability is excellent and the durability is good.
In addition, the fiber length of the fibrous material is not particularly limited, and the fibrous material is not particularly limited as long as it has a length of 50 times or more, preferably 100 times or more, more preferably 200 times or more of the fiber diameter. It is preferable because they easily come into contact with each other and contribute to improving the durability of the coating layer as well as improving the conductivity by entanglement of the fibers. When the fiber length with respect to the fiber diameter is less than 50 times, the fibrous materials are hardly in contact with each other, and the effect of resistance control ability is reduced, which is not preferable.

  Although content of a fibrous material is suitably selected also by the material which comprises a covering clothing layer, Preferably it is the range of 1 to 70 weight%, More preferably, it is the range of 10 to 50 weight%. If it is less than 1% by weight, the contact between the fibrous materials is insufficient, and the resistance adjustment ability of the coating layer may be insufficient. Conversely, if it exceeds 70% by weight, irregularities occur in the coating layer, Surface smoothness may deteriorate.

  The composition of the fibrous material includes a polymer that can be made into a solution or an emulsion by adding water and / or an organic solvent, a polymer that melts in a heated state and shows a liquid state, and further a liquid state at room temperature. There is no particular limitation as long as it is a polymer to be shown, and if it has a molecular weight, it can be used from thousands of oligomers to millions of ultrapolymers. These fibrous materials are mainly used in the form of an aqueous solution or a water emulsion in the carrier of the present invention, but are dissolved in an organic solvent such as alcohol, toluene, methyl ethyl ketone (MEK), xylene, ethyl acetate or the like. It may be used in the form of a solvent solution or an organic solvent emulsion.

  Moreover, as a polymer that can be made into a solution by adding water, a natural or synthetic water-soluble polymer having a hydrophilic group such as an ether group, an epoxy group, a carboxy group, a hydroxyl group, a sulfonic acid group, or a water-dispersed The emulsion resin is preferably used.

Examples of the water-soluble polymer include a polymer resin having a hydrogen bonding functional group. For example, a polymer having a hydroxyl group, a carboxylic acid, an amino group, a sulfonic acid, an amide group, or the like is preferable. For example, starches such as oxidized starch and dextrin; polyvinyl alcohol and derivatives thereof; carboxymethylcellulose, methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, methylcellulose, hydroxyethylmethylcellulose, carboxymethylcellulose, cellulose itself in which pulp fibers are dissolved, etc. Natural or synthetic cellulose; gelatin, casein, starch; polyvinylpyrrolidone, polyacrylamide, polyacrylic acid, polyhydroxyethyl acrylate, polyacryloylmorpholine, water-soluble polyvinyl acetal, poly-N-vinylacetamide, poly-N-vinylformamide and so on. Among these, polyvinyl alcohol and its derivatives, and starches are preferable because they are inexpensive and can provide fibrous materials having properties suitable for various purposes.
Among these, linear polymers are preferable because polyvinyl alcohol derivatives and cellulose derivatives are easily formed by electrospinning. In addition, conductive polymers such as polyaniline, polyacetylene, polyazulene, polyphenylacetylene, polydiacetylene, polypyrrole, polythiophene, polybenzthiophene, polyparaphenylene, polyparaphenylene vinylene, polyimidazole, polybenzimidazole, polyaniline, polythiophene, etc. Is excellent in compatibility with the water-soluble polymer, and can be suitably used. Moreover, you may use the polymer which introduce | transduced substituents, such as a hydroxyl group, an amino group, carboxylic acid, and a sulfonic acid, into these conductive polymers.

  In addition, conductive polymers such as polyaniline, polyacetylene, polyazulene, polyphenylacetylene, polydiacetylene, polypyrrole, polythiophene, polybenzthiophene, polyparaphenylene, polyparaphenylene vinylene, polyimidazole, polybenzimidazole, polyaniline, polythiophene, etc. Is excellent in compatibility with the water-soluble polymer, and can be suitably used. Moreover, you may use the polymer which introduce | transduced substituents, such as a hydroxyl group, an amino group, carboxylic acid, and a sulfonic acid, into these conductive polymers.

  Examples of the fibrous metal compound material of the present invention include metal oxides, metal nitrides, metal sulfides, metal carbides, metal fluorides, and metal borides. Here, a metal oxide can be produced as the metal compound by using a metal alkoxide as the precursor of the metal compound. Examples of the metal oxide include zinc oxide, tin oxide, indium oxide, cadmium oxide and copper oxide, and conductive oxides such as composite metal oxides obtained by combining these metal oxides with other metal oxides. preferable.

  These fibrous materials may be used alone or in combination of two or more according to the purpose. By mixing and using two or more kinds of fibrous materials, the compatibility and the difference in solubility in the solvent (water or organic solvent) used at the time of production are adjusted, and resistance control of the obtained fibrous material is performed. Performance and physical properties (fiber diameter, fiber length, cross-sectional shape, fiber surface shape, etc. of the fibrous material) can be adjusted.

  In addition to the fiber material as described above, the fibrous material has a viscosity or surface tension of the solution or emulsion when the fibrous material is used as a solution or emulsion within a range not impairing the effects of the present invention. In order to change the electrical conductivity, the solid content concentration, which is the ratio of the fibrous material to the solvent, and the molecular weight of the fibrous material are adjusted, inorganic salts such as NaCl and polyphosphate, sodium salts and ammonium salts of various carboxylic acids, etc. Organic salts, anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants and other surfactants, wetting agents such as polycarboxylic acids and sulfosuccinic acids, polyethylene glycol, antifoaming agents, Furthermore, in order to adjust electrical conductivity, additives such as styrene sulfonate, quaternary cations and amine compounds, and water resistance agents such as coupling agents and crosslinking agents may be included.

Although the fibrous material of this invention is not limited, For example, it can manufacture by the following method.
[Electrospinning method]

  The electrospinning method is known as a fiberizing method using the power of electricity by Dr. Frank Ko of Drexel University, one of the authorities. FIG. 1 shows a schematic diagram of an example of an electrospinning apparatus used in the present invention. In FIG. 1, a direct current is applied by a power source (4) between a nozzle (1) for supplying a conductive polymer or metal compound precursor-containing solution or dispersion and a receiver (2) containing a carrier such as a core material. When a high voltage is applied, the metal compound precursor-containing solution or dispersion is jetted toward the receptor (2), and the metal compound precursor is deposited on the receptor (2) by the electric field generated by the high voltage. . At this time, the metal compound precursor-containing solution or dispersion is ejected as fine droplets from the nozzle (1) due to the surface tension, but charges are collected on the surface of the droplets and the liquids repel each other. . When the repulsive force of this charge exceeds the surface tension, the droplet breaks up and becomes a jet (5). At this time, the solvent in the conductive polymer or metal compound precursor-containing solution or dispersion is volatilized, the charge repulsion is further increased, and the jet (5) is further divided into fine jets (5). In this jet (5), the metal compound precursor in the conductive polymer or metal compound precursor-containing solution or dispersion is oriented, and the metal compound precursor becomes an elongated fiber, reaching the receptor (2). And agglomerated to form a deposited layer composed of a fibrous material of the metal compound precursor on the support in the receiver (2).

  In the electrospinning method, by appropriately selecting the applied voltage, the distance between the nozzle (1) and the receiver (2), the discharge port diameter of the nozzle (1), the composition of the metal compound precursor-containing solution or dispersion, etc. A fibrous product of the metal compound precursor having a desired average diameter and average length is obtained.

  Although the applied voltage in the said electrospinning method is not specifically limited, The range of 20-30 kV is preferable. If the applied voltage is less than 20 kV, the metal compound precursor may not be sufficiently fiberized, and if it exceeds 30 kV, it is dangerous for the apparatus and the human body.

  The distance between the nozzle (1) and the receiver (2) in the electrospinning method varies depending on the applied voltage and the viscosity and conductivity of the metal compound precursor-containing solution or dispersion, but is in the range of 5 to 15 cm. Is preferred. Even if the distance between the nozzle (1) and the receiver (2) or the like is less than 5 cm or more than 15 cm, a good fibrous material of the metal compound precursor may not be obtained.

  Although the discharge port diameter of the nozzle (1) in the said electrospinning method is not specifically limited, The range of 300-500 micrometers is preferable. Even if the discharge port diameter of the nozzle (1) is less than 300 μm or more than 500 μm, a good fibrous material of the metal compound precursor may not be obtained.

[Image forming apparatus, process cartridge]
As illustrated in FIG. 2, the process cartridge for an image forming apparatus according to the present invention includes a photoreceptor (101), and in addition, a charging unit (102), a developing unit (104), a transfer unit (108), and a cleaning unit. An apparatus (part) that includes at least one of a means (107) and a charge eliminating means (not shown) and is detachable from the main body of the image forming apparatus.
Referring to the image forming process by the apparatus illustrated in FIG. 2, the surface of the photoconductor (101) is exposed by charging by the charging means (102) and exposure by the exposure means (103) while rotating in the direction of the arrow. An electrostatic latent image corresponding to the image is formed, and the electrostatic latent image is developed with toner by the developing means (104). The toner development is transferred to the transfer body (105) by the transfer means (108), and printed. Out. Next, the surface of the photoconductor after the image transfer is cleaned by a cleaning unit (107), and further neutralized by a neutralizing unit (not shown), and the above operation is repeated again.

Still another embodiment for carrying out the image forming method of the present invention by an example of the image forming apparatus of the present invention (for example, the image forming apparatus shown in FIGS. 3 to 6) will be described with reference to FIG.
The image forming apparatus (100) of the example shown in FIG. 3 includes a photosensitive drum (10) (hereinafter referred to as “photosensitive member 10”) as an electrostatic latent image carrier, a roller-shaped charging unit (20), and an exposure unit. (30), a developing means (40), an intermediate transfer member (50), a cleaning means (60) having a cleaning blade, and a static elimination lamp as a static elimination means (70).

  The intermediate transfer member (50) is an endless belt, and is designed to be movable in the direction of the arrow by three rollers (51) that are arranged on the inner side and stretch the belt. A part of the three rollers (51) also functions as a transfer bias roller capable of applying a predetermined transfer bias (primary transfer bias) to the intermediate transfer member (50). The intermediate transfer member (50) is provided with a cleaning means having a cleaning blade in the vicinity thereof, and transfers (secondary transfer) a developed image (image-forming particle image) onto a transfer sheet as a final transfer material. A transfer roller as a transfer means capable of applying a transfer bias is disposed opposite to the transfer roller. Around the intermediate transfer member (50), there is a corona charger (58) for applying a charge to the image-forming particle image on the intermediate transfer member (50) in the rotational direction of the intermediate transfer member (50). It is arranged between the contact portion between the photoconductor (10) and the intermediate transfer member (50) and the contact portion between the intermediate transfer member (50) and the transfer paper.

  The developing means (40) includes a developing belt (41) as a developer carrier, a black developing means (unit) (45K) provided around the developing belt (41), a yellow developing means (unit) (45Y), It is composed of a magenta developing means (unit) (45M) and a cyan developing means (unit) (45C). The black developing means (45K) includes a developer accommodating portion (42K), a developer supply roller (43K), and a developing roller (44K). The yellow developing means (45Y) is provided with a developer accommodating portion ( 42Y), a developer supply roller (43Y), and a development roller (44Y). The magenta developing means (45M) includes a developer accommodating portion (42M), a developer supply roller (43M), and a development roller (44M). The cyan developing means (45C) includes a developer container (42C), a developer supply roller (43C), and a developing roller (44C). Further, the developing belt (41) is an endless belt, is rotatably stretched around a plurality of belt rollers, and a part thereof is in contact with the photoreceptor (10).

  In the image forming apparatus (100) shown in FIG. 3, for example, the charging means (20) uniformly charges the photosensitive drum (10). The exposure means (30) exposes the photosensitive drum (10) imagewise to form an electrostatic latent image. The electrostatic latent image formed on the photosensitive drum (10) is developed by supplying image forming particles from the developing means (40) to form a visible image (image forming particle image). The visible image (image-forming particle image) is transferred (primary transfer) onto the intermediate transfer body (50) by the voltage applied from the roller (51), and further transferred onto the transfer paper (secondary transfer). As a result, a transfer image is formed on the transfer paper. The residual image forming particles on the photoreceptor (10) are removed by the cleaning means (60), and the charge on the photoreceptor (10) is once removed by the charge eliminating means (charge eliminating lamp) (70).

  Another mode for carrying out the image forming method of the present invention by the image forming apparatus of the present invention will be described with reference to FIG. The image forming apparatus (100) shown in FIG. 4 does not include the developing belt (41) in the image forming apparatus (100) shown in FIG. 3, and a black developing means (developing unit) (developing unit) ( 45K), yellow developing means (developing unit) (45Y), magenta developing means (developing unit) (45M) and cyan developing means (developing unit) (45C) are arranged directly opposite to each other, as shown in FIG. The image forming apparatus (100) shown in FIG. In FIG. 4, the same components as those in FIG. 3 are denoted by the same reference numerals.

Still another embodiment for carrying out the image forming method of the present invention by the image forming apparatus of the present invention will be described with reference to FIG. The tandem image forming apparatus (120) shown in FIG. 5 is a tandem color image forming apparatus. The tandem image forming apparatus (120) includes a copying apparatus main body (150), a paper feed table (200), a scanner (300), and an automatic document feeder (ADF) (400). The copying machine main body (150) is provided with an endless belt-like intermediate transfer member (50) at the center. The intermediate transfer member (50) is stretched around the support rollers (14), (15), and (16), and can rotate clockwise in FIG. An intermediate transfer body cleaning device (17) for removing residual image forming particles on the intermediate transfer body (50) is disposed in the vicinity of the support roller (15). The intermediate transfer member (50) stretched between the support roller (14) and the support roller (15) has four image forming units (18) of yellow, cyan, magenta, and black along the conveyance direction. A tandem developing means (120) arranged opposite to each other is arranged. An exposure means (21) is disposed in the vicinity of the tandem developing means (120). A secondary transfer unit (22) is disposed on the side of the intermediate transfer member (50) opposite to the side on which the tandem type developing unit (120) is disposed. In the secondary transfer means (22), a secondary transfer belt (24), which is an endless belt, is stretched between a pair of rollers (23), and a transfer sheet conveyed on the secondary transfer belt (24); The intermediate transfer member (50) can contact each other. A fixing means (25) is disposed in the vicinity of the secondary transfer means (22). The fixing means (25) includes a fixing belt (26) that is an endless belt, and a pressure roller (27) that is pressed against the fixing belt (26).
In the tandem image forming apparatus (120), a sheet reversal is performed in the vicinity of the secondary transfer unit (22) and the fixing unit (25) for reversing the transfer paper in order to form an image on both sides of the transfer paper. A device (28) is arranged.

  Next, full color image formation (color copying) using the tandem developing means (120) will be described. That is, first, a document is set on the document table (130) of the automatic document feeder (ADF) (400) or the automatic document feeder (400) is opened and the contact glass (32) of the scanner (300) is opened. A document is set on the document and the automatic document feeder (400) is closed.

  When a start switch (not shown) is pressed, when a document is set on the automatic document feeder (400), the document is transported and moved onto the contact glass (32). ) Immediately after the document is set on the scanner (300), the first traveling body (33) and the second traveling body (34) travel. At this time, light from the light source is irradiated by the first traveling body (33) and reflected light from the document surface is reflected by the mirror in the second traveling body (34), and is read through the imaging lens (35). The color original (color image) is read at (36), and is read as black, yellow, magenta and cyan image information.

  Each image information of black, yellow, magenta and cyan is stored in each image forming means (18) (black image forming means, yellow image forming means, magenta image forming means and cyan) in the tandem developing means (120). Image forming means), and image forming particle images of black, yellow, magenta and cyan are formed in each image forming means. That is, each image forming means (18) (black image forming means, yellow image forming means, magenta image forming means and cyan image forming means) in the tandem developing means (120) is partially enlarged in FIG. As shown in FIG. 6, which is a schematic diagram, the photoreceptor (10) (the photoreceptor for black (10K), the photoreceptor for yellow (10Y), the photoreceptor for magenta (10M), and the photoreceptor for cyan (10C), respectively. ), Charging means (59) for uniformly charging the photoconductor, and exposing the photoconductor for each color image corresponding to each color image information (L in FIG. 6). Exposure means for forming an electrostatic latent image corresponding to each color image on the surface, and each color developer (black developer, yellow developer, magenta developer and cyan developer) of the present invention on the electrostatic latent image. Use and develop each A developing means (61) for forming a toner image with a developer, a transfer charger (62) for transferring the developed toner image onto the intermediate transfer body (50), and a photoreceptor cleaning means (63). And a static eliminator (64), and each monochrome image (black image, yellow image, magenta image, and cyan image) can be formed based on the image information of each color. The black image, the yellow image, the magenta image, and the cyan image thus formed are transferred onto the intermediate transfer member (50) that is rotated by the support rollers (14), (15), and (16) in FIG. The black image formed on the black photoconductor (10K), the yellow image formed on the yellow photoconductor (10Y), the magenta image formed on the magenta photoconductor (10M), and the cyan photoconductor, respectively. The cyan image formed on the body (10C) is sequentially transferred (primary transfer). Then, the black image, the yellow image, the magenta image, and the cyan image are superimposed on the intermediate transfer member (50) to form a composite color image (color transfer image).

On the other hand, in the paper feed table (200), one of the paper feed rollers (142) is selectively rotated so that the sheet (recording paper) is fed from one of the paper feed cassettes (144) provided in the paper bank (143). ), Separated one by one by the separation roller (145), sent to the paper feed path (146), and conveyed by the conveyance roller (147) to the paper feed path (148) in the copier body (150). Guide and stop against the registration roller (49). Alternatively, the sheet feed roller (142) is rotated to feed out the sheets (recording paper) on the manual feed tray (54), separated one by one by the separation roller, and put into the manual feed path (53). 49) and stop. The registration roller (49) is generally used while being grounded, but may be used in a state where a bias is applied to remove paper dust from the sheet.
Then, the registration roller (49) is rotated in synchronism with the synthesized color image (color transfer image) in which the respective toners are synthesized on the intermediate transfer member (50), and the intermediate transfer member (50) and the secondary transfer means ( 22), a sheet (recording paper) is sent to the sheet (recording paper), and the composite color image (color transfer image) is transferred (secondary transfer) onto the sheet (recording paper) by the secondary transfer means (22). A color image is transferred and formed on the sheet (recording paper). The residual toner on the intermediate transfer member (50) after the image transfer is cleaned by the intermediate transfer member cleaning device (17).

  The sheet (recording paper) on which the color image has been transferred is transported by the secondary transfer means (22) and sent to the fixing means (25). The fixing means (25) generates heat and pressure. The composite color image (color transfer image) is fixed on the sheet (recording paper). Thereafter, the sheet (recording paper) is switched by the switching claw (55) and discharged by the discharge roller (56) and stacked on the discharge tray (57), or switched by the switching claw (55) and the sheet is reversed. The image is reversed by the device (28) and guided again to the transfer position, and an image is recorded also on the back surface. Then, the image is discharged by the discharge roller (56) and stacked on the discharge tray (57).

On the other hand, the intermediate transfer member (10) after the image transfer is removed by the intermediate transfer member cleaning device (17) to remove residual toner remaining on the intermediate transfer member (10) after the image transfer, and the tandem image forming device (20). To prepare for image formation again.
Here, the registration roller (49) is generally used while being grounded, but it is also possible to apply a bias for removing paper dust from the sheet.
In the tandem image forming apparatus (20) described above, the individual image forming means (18) includes, for example, a charging device (60), around a drum-shaped photoconductor (40), as shown in FIG. A developing device (61), a primary transfer device (62), a photoconductor cleaning device (63), a charge eliminating device (64), and the like are provided. 10 will be described. (65) is a developer on the developing sleeve, (68) is a stirring paddle, (69) is a partition plate, (71) is a toner concentration sensor, (72) is a developing sleeve, ( 73) a doctor, (75) a cleaning blade, (76) a cleaning brush, (77) a cleaning roller, (78) a cleaning blade, (79) a toner discharge auger, and (80) a driving device.

  Examples of the present invention will be described below, but the present invention is not limited to the following examples.

(Production Example 1)
[Production of Toner 1]
50 parts by mass of a polyester resin (weight average molecular weight = 12,000), 2 parts by mass of a copper phthalocyanine pigment, and the following structural formula (A) (nonylene perfluoroether, iodine salt of p-trimethylaminopropylamidophenyl) 2 parts by weight of the charge control agent is kneaded at 120 ° C. using a hot roll, cooled and solidified, pulverized and classified, and the volume average particle diameter is 7.1 μm, the number average particle diameter is 5.8 μm, Toner base particles having an average circularity of 0.953 were obtained.

次に、得られたトナー母体粒子５０質量部に対し、シリカＲ９７２（日本アエロジル株式会社製）を０．５質量部添加して混合し、「トナー１」を作製した。

Next, 0.5 parts by mass of silica R972 (manufactured by Nippon Aerosil Co., Ltd.) was added to and mixed with 50 parts by mass of the obtained toner base particles to prepare “Toner 1”.

(Production Example 2)
[Production of Toner 2]
50 parts by mass of a polyester resin (weight average molecular weight = 12,000), 5 parts by mass of carbon black, and 2 parts by mass of a chromium-containing azo dye represented by the following structural formula (B) were kneaded at 120 ° C. using a hot roll. After cooling and solidifying, the mixture was pulverized and classified to obtain toner base particles having a volume average particle size of 7.3 μm, a number average particle size of 6.0 μm, and an average circularity of 0.955.

次に、得られたトナー母体粒子５０質量部に対し、シリカＲ９７２（日本アエロジル株式会社製）を０．５質量部添加し、混合して、「トナー２」を作製した。

Next, 0.5 parts by mass of silica R972 (manufactured by Nippon Aerosil Co., Ltd.) was added to and mixed with 50 parts by mass of the obtained toner base particles to prepare “Toner 2”.

(Production Example 3)
[Preparation of Toner 3]
[Synthesis of organic fine particle emulsion]
In a reaction vessel equipped with a stir bar and a thermometer, 683 parts by mass of water, 11 parts by mass of sodium salt of ethylene oxide methacrylate adduct sulfate (Eleminol RS-30, manufactured by Sanyo Chemical Industries, Ltd.), 83 parts by mass of styrene Part, 83 parts by weight of methacrylic acid, 110 parts by weight of butyl acrylate, and 1 part by weight of ammonium persulfate were added and stirred at 400 rpm for 15 minutes to obtain a white emulsion. This emulsion was heated to raise the system temperature to 75 ° C. and reacted for 5 hours. Next, 30 parts by mass of a 1% by mass ammonium persulfate aqueous solution was added, and the mixture was aged at 75 ° C. for 5 hours to form a vinyl resin (a copolymer of methacrylic acid-butyl acrylate-methacrylic acid ethylene oxide adduct sulfate sodium salt). An aqueous dispersion was obtained. This is designated as [fine particle dispersion 1].
The volume average particle diameter of the fine particles contained in the obtained [fine particle dispersion 1] was measured with a particle size distribution measuring apparatus (“LA-920”, manufactured by Horiba, Ltd.) using a laser scattering method, and found to be 105 nm. It was. In addition, a part of [Fine Particle Dispersion 1] was dried to isolate only the resin component. The glass transition temperature (Tg) of this resin was 59 ° C., and the weight average molecular weight (Mw) was 150,000.

[Preparation of aqueous phase]
990 parts by mass of water, 83 parts by mass of [fine particle dispersion 1], 37 parts by mass of a 48.5% aqueous solution of dodecyl diphenyl ether disulfonate (Eleminol MON-7, manufactured by Sanyo Chemical Industries), and 90 parts by mass of ethyl acetate The mixture was stirred to obtain a milky white liquid. This liquid is designated [Aqueous Phase 1].

[Synthesis of low molecular weight polyester]
In a reaction vessel equipped with a cooling tube, a stirrer, and a nitrogen introduction tube, 229 parts by mass of bisphenol A ethylene oxide 2 mol adduct, 529 parts by mass of bisphenol A propylene oxide 3 mol adduct, 208 parts by mass of terephthalic acid, 46 adipic acid 46 Part by mass and 2 parts by mass of dibutyltin oxide were charged and reacted at 230 ° C. for 8 hours under normal pressure. Subsequently, after reacting under reduced pressure of 10 to 15 mmHg for 5 hours, 44 parts by mass of trimellitic anhydride was put in the reaction vessel and reacted at 180 ° C. and normal pressure for 2 hours to synthesize [low molecular weight polyester 1].
The obtained [low molecular weight polyester 1] had a glass transition temperature (Tg) of 45 ° C., a weight average molecular weight (Mw) of 5800, a number average molecular weight of 2600, and an acid value of 24 mgKOH / g. .

[Synthesis of polyester prepolymer]
In a reaction vessel equipped with a cooling tube, a stirrer, and a nitrogen introduction tube, 682 parts by mass of bisphenol A ethylene oxide 2 mol adduct, 81 parts by mass of bisphenol A propylene oxide 2 mol adduct, 283 parts by mass of terephthalic acid, 22 parts by mass of merit acid and 2 parts by mass of dibutyltin oxide were added and reacted at 230 ° C. for 8 hours under normal pressure. Subsequently, it reacted for 5 hours under the reduced pressure of 10-15 mmHg, and the [intermediate polyester 1] was synthesize | combined.
The obtained [Intermediate polyester 1] had a number average molecular weight of 250, a weight average molecular weight of 9,500, a glass transition temperature (Tg) of 55 ° C., an acid value of 0.5 mgKOH / g, and a hydroxyl value of 51.
Next, 410 parts by mass of [Intermediate Polyester 1], 89 parts by mass of isophorone diisocyanate and 500 parts by mass of ethyl acetate are placed in a reaction vessel equipped with a cooling tube, a stirrer, and a nitrogen introduction tube, and are stirred at 50 ° C. for 5 hours. Reaction was performed to obtain [Prepolymer 1].
The obtained [Prepolymer 1] had a free isocyanate mass% of 1.74%.

[Synthesis of ketimine]
In a reaction vessel equipped with a stir bar and a thermometer, 170 parts by mass of isophoronediamine and 75 parts by mass of methyl ethyl ketone were charged and reacted at 50 ° C. for 5 hours to synthesize [ketimine compound 1]. The amine value of the obtained [ketimine compound 1] was 418.

[Preparation of master batch (MB)]
1,200 parts by weight of water, 540 parts by weight of carbon black (PBk-7: Printex 60, manufactured by Degussa) [DBP oil absorption = 114 ml / 50 mg, pH = 10], and polyester resin (manufactured by Sanyo Chemical Industries, RS801) 1,200 parts by mass was added and mixed with a Henschel mixer (Mitsui Mining Co., Ltd.). The obtained mixture was kneaded at 150 ° C. for 30 minutes using two rolls, rolled and cooled, and pulverized with a pulverizer to obtain a master batch. This is designated as [Masterbatch 1].

[Preparation of oil phase]
In a reaction vessel equipped with a stir bar and a thermometer, 300 parts by weight of [low molecular weight polyester 1], 90 parts by weight of carnauba wax, 10 parts by weight of rice wax, and 500 parts by weight of ethyl acetate were charged and stirred with 79 parts. After dissolving at 0 ° C., it was rapidly cooled to 4 ° C. at once. Using a bead mill (Ultra Visco Mill, manufactured by Imex Co., Ltd.), the liquid feeding speed is 1 kg / hr, the disk peripheral speed is 6 m / sec, and 0.5 mm zirconia beads are filled by 80% by volume, and dispersion is performed under conditions of 3 passes. And a wax dispersion having a volume average particle size of 0.6 μm was obtained.
Next, 500 parts by mass of “Masterbatch 1” and 640 parts by mass of a 70% ethyl acetate solution of “Low molecular polyester 1” were added and mixed for 10 hours. “Oil phase 1” adjusted to mass% was prepared.

[Preparation of polymerized toner]
[Oil Phase 1] 73.2 parts by mass, [Prepolymer 1] 6.8 parts by mass, and [Ketimine Compound 1] 0.48 parts by mass were placed in a container and mixed well with [Emulsified oil phase 1]. 120 parts by mass of aqueous phase 1] was added, mixed for 1 minute with a homomixer, and then allowed to converge with a paddle for 1 hour with gentle stirring to obtain [Emulsion slurry 1].
The obtained [Emulsion slurry 1] was desolvated at 30 ° C. for 1 hour, further aged at 60 ° C. for 5 hours, washed with water, filtered and dried, and then sieved with a mesh of 75 μm, and the volume average particle diameter Toner base particles having a particle size of 6.1 μm, a number average particle size of 5.4 μm, and an average circularity of 0.972 were prepared.
Next, 0.7 parts by mass of hydrophobic silica and 0.3 parts by mass of hydrophobized titanium oxide were mixed with 50 parts by mass of the obtained toner base particles using a Henschel mixer to prepare “Toner 3”.

(Production Example 4)
[Preparation of fibrous material 1]
A solution of polyaniline in N-methyl-2-pyrrolidone (concentration 2%, containing 0.02% acetic acid) was placed in a container (made of plastic) having a capacity of 50 cc, and the inner diameter was 0.2 mm using a pump. The glass tube (outer diameter 5 mm) was connected via a silicone tube. The cross section of the tip of the glass tube was processed into a conical shape. A stainless steel collection container was placed 30 cm away from the tip of the glass tube and grounded. The stainless steel collection container is a plus of a high voltage source, a copper wire is put in a glass tube, and the copper wire is grounded. A voltage of 13 kV was applied between the glass tube and the collection container to form the fibrous material 1 in the collection container. The current value at this time was 5 to 10 μA, and the flow rate was 5 μl / sec. The amount of application of the fibrous material 1 was 0.1 g / m ² in terms of solid content (the amount of application was calculated from the amount of liquid consumption. The same applies hereinafter).

(Production Example 5)
[Preparation of fibrous material 2]
A fibrous material 2 was produced in the same manner as in Example 1 except that an aqueous emulsion solution of polythiophene (solid 0.5%, pH 2.2, trademark: Denatron P502RG, manufactured by Nagase Chemtech) was used instead of the polyaniline solution. did. The amount of polythiophene applied was 0.01 g / m ^{2 in} terms of solid content.

Example 1
[Production of Carrier 1]
Toluene solution (solid content concentration 10 mass) of silicone resin A (mass average molecular weight = 12,500, number average molecular weight (Mn) = 6,500, Mw / Mn = 1.92, phase transition temperature from solid = 45 ° C.) %) After stirring a dispersion of 500 parts by mass, 5 parts by mass of the catalyst [(CH ₃ ) ₂ Sn (OCOCH ₃ ) ₂ ] and 50 parts by mass of the fibrous material, a ferrite core material having a volume average particle diameter of 35 μm ( (Saturation magnetic moment at 1 k gauss = 65 emu / g) With respect to 5000 parts by mass, using a fluidized bed type coating apparatus, it was applied over 20 minutes at a rate of 50 g / min in an atmosphere of 50 ° C. The ferrite particles coated with the silicone resin were heated at 200 ° C. for 1 hour to prepare a carrier 1.
With respect to the obtained comparative carrier 1, the average thickness of the coating layer measured in the same manner as in Example 1 was 0.65 μm, and the electric resistance was Log R 13.7 Ω · cm.

(Example 2)
[Production of Carrier 2]
In Example 1, silicone resin A was changed to silicone resin B (weight average molecular weight (Mw) = 18,000, number average molecular weight (Mn) = 9,000, Mw / Mn = 2.00, transition temperature from solid = A carrier 2 was produced in the same manner as in Example 1 except that the temperature was changed to 60 ° C.
The thickness of the coating layer of the obtained carrier 2 was 0.62 μm, and the electric resistance was LogR13.7Ω · cm.

(Example 3)
[Production of Carrier 3]
A carrier 3 was produced in the same manner as in Example 1 except that the fibrous material 1 was changed to the fibrous material 2 in Example 1.
The thickness of the coating layer of the obtained carrier 3 was 0.64 μm, and the electric resistance was Log R 13.9 Ω · cm.

Example 4
[Preparation of Carrier 4]
A carrier 4 was produced in the same manner as in Example 2 except that the fibrous material 1 was changed to the fibrous material 2 in Example 2.
The thickness of the coating layer of the obtained carrier 4 was 0.62 μm, and the electric resistance was Log R 14.0 Ω · cm.

(Example 5)
[Preparation of Carrier 5]
A solution of polyaniline in N-methyl-2-pyrrolidone (concentration 2%, containing 0.02% acetic acid) was placed in a container (made of plastic) having a capacity of 50 cc, and the inner diameter was 0.2 mm using a pump. The glass tube (outer diameter 5 mm) was connected via a silicone tube. The cross section of the tip of the glass tube was processed into a conical shape. A stainless steel collection container with a shaker was placed 30 cm away from the tip of the glass tube and grounded. After putting 5000 parts by mass of ferrite core material (saturation magnetic moment at 1 k gauss = 65 emu / g) having a volume average particle diameter of 35 μm into the collection container, the stainless steel collection container is used as a high voltage source plus a glass tube. A copper wire was put inside, and the copper wire was grounded. A voltage of 13 kV was applied between the glass tube and the collection container, and a fibrous material was formed on the surface of the core material in the container while shaking the collection container, whereby a mixture 1 was obtained. The current value at this time was 5 to 10 μA, and the flow rate was 5 μl / sec. The coating amount of the fibrous material was 50 parts by mass in terms of solid content.

Toluene solution (solid content concentration 10 mass) of silicone resin A (mass average molecular weight = 12,500, number average molecular weight (Mn) = 6,500, Mw / Mn = 1.92, phase transition temperature from solid = 45 ° C.) %) After stirring a dispersion of 500 parts by mass and 5 parts by mass of the catalyst [(CH ₃ ) ₂ Sn (OCOCH ₃ ) ₂ ], 50 parts by mass of the mixture 1, 5050 parts by mass using a fluidized bed type coating apparatus. The ferrite particles coated at a rate of 50 g / min for 20 minutes in an atmosphere at 50 ° C. and coated with the obtained silicone resin were heated at 200 ° C. for 1 hour to prepare a carrier 5.
The thickness of the coating layer of the obtained carrier 5 was 0.60 μm, and the electric resistance was LogR13.3Ω · cm.

(Comparative Example 1)
[Production of Comparative Carrier 1]
Toluene solution (solid content concentration 10 mass) of silicone resin A (mass average molecular weight = 12,500, number average molecular weight (Mn) = 6,500, Mw / Mn = 1.92, phase transition temperature from solid = 45 ° C.) %) 500 parts by mass, a dispersion of 5 parts by mass of catalyst [(CH ₃ ) ₂ Sn (OCOCH ₃ ) ₂ ], and alumina (Sumitomo Chemical Co., Ltd., Sumiko Random AA-04, 0.4 μm, axial ratio 1) .1) After stirring 50 parts by mass, a ferrite core material having a volume average particle size of 35 μm (saturated magnetic moment at 1 k gauss = 65 emu / g) is used at 5000 ° C. using a fluidized bed type coating apparatus. The carrier particles were coated at a rate of 50 g / min for 20 minutes under the atmosphere of the above, and the obtained ferrite particles coated with the silicone resin were heated at 200 ° C. for 1 hour to prepare a comparative carrier 1.
With respect to the obtained comparative carrier 1, the average thickness of the coating layer measured in the same manner as in Example 1 was 0.72 μm, and the electric resistance was Log R 15.4 Ω · cm.

(Examples 6 to 12, Comparative Example 2)
[Production of developer]
The produced carriers 1 to 5 and comparative carrier 1 and toners 1 to 3 were combined as shown in Table 1 below, and developers of Examples 6 to 12 and Comparative Example 2 were produced by a conventional method.

  Using the obtained developers, image density, toner scattering property, background stain, edge effect, and comprehensive evaluation were performed as follows. The results are shown in Table 1.

<Image density>
Next, each developer obtained was attached to copy paper (TYPE6000 <70W>, manufactured by Ricoh Co., Ltd.) using a tandem color image forming apparatus (image Neo 450, manufactured by Ricoh Co., Ltd.). A solid image with an amount of 50 ± 0.05 mg / cm ² was formed. The solid image was repeatedly formed on 500,000 copy sheets.
The image density of the obtained solid image was visually observed for the initial stage and after the endurance of 500,000 sheets, and evaluated based on the following criteria. Note that the higher the image density obtained, the higher the density image can be formed. This evaluation corresponds to an embodiment of the process cartridge, the image forming apparatus, and the image forming method of the present invention.
〔Evaluation criteria〕
A: There was no change in image density and high image quality was obtained at the initial stage and after endurance of 500,000 sheets.
○: After 500,000 sheets were used, the image density was slightly reduced, but high image quality was obtained.
(Triangle | delta): After 500,000 sheet durability, the image density fell and the image quality fell.
X: The image density was remarkably lowered and the image quality was greatly lowered after the endurance of 500,000 sheets.

<Toner scattering property>
The extent of toner contamination in the machine when a chart with an image area ratio of 5% is output continuously by 500,000 sheets using a tandem color image forming apparatus (Imagio Neo 450, manufactured by Ricoh Co., Ltd.) is visually checked according to the following criteria. Evaluation was made in 4 stages.
〔Evaluation criteria〕
A: There is no toner contamination in the machine and it is in an excellent state.
○: There is no toner contamination in the machine and it is in a good state.
Δ: There is toner contamination in the machine, but it is a practically usable level.
X: Toner contamination in the machine is severe and the level is not practical.

<Soil dirt>
The chart below shows the degree of background contamination of the image background when the image area ratio of 5% is continuously output by using a tandem type color image forming apparatus (image Neo 450, manufactured by Ricoh Co., Ltd.). It was evaluated by.
〔Evaluation criteria〕
○: No background stains in the image background.
Δ: Soil is slightly generated in the background portion of the image.
X: Soil is generated in the background portion of the image.

<Edge effect>
A developer is set on a commercially available digital full color printer (IPSiO CX8200 manufactured by Ricoh), and a test pattern having a large area image is output. The difference between the thinness of the image density in the central portion of the image pattern thus obtained and the darkness of the edge portion was ranked as follows and evaluated according to the following criteria.
〔Evaluation criteria〕
A: There is no density difference.
○: There is a slight density difference.
Δ: Allowable although there is a difference in density.
X: Unacceptable due to density difference.

<Comprehensive evaluation>
From the above evaluation results, the following criteria were used for overall evaluation.
〔Evaluation criteria〕
◎: Very good ○: Good ×: Bad

表１の結果から、被覆層中に繊維状材料を含有するキャリア１〜５を用いた実施例６〜１２の現像剤は、比較例２の現像剤に比べて、トナー飛散や地汚れがなく、エッジ効果のない高画像濃度が得られることが確認できた。

From the results of Table 1, the developers of Examples 6 to 12 using the carriers 1 to 5 containing the fibrous material in the coating layer are free from toner scattering and background staining as compared with the developer of Comparative Example 2. It was confirmed that a high image density without an edge effect was obtained.

It is the schematic of an example of the electrospinning apparatus utilized by this invention. FIG. 2 is a schematic diagram illustrating an example of a process cartridge for an electrophotographic apparatus according to the present invention. It is the schematic which shows another example of the image forming apparatus which enforces the image forming method of this invention. It is the schematic which shows the further another example of the image forming apparatus which enforces the image forming method of this invention. It is the schematic which shows an example of the further another image forming apparatus (tandem type color image forming apparatus) for enforcing the image forming method of this invention. FIG. 6 is a partially enlarged schematic view of the image forming apparatus shown in FIG. 5.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Nozzle 2 Receptor 3 Shaker 4 Power supply 5 Jet 10 Photosensitive body (photosensitive drum)
10K black photoconductor 10Y yellow photoconductor 10M magenta photoconductor 10C cyan photoconductor 14 support roller 15 support roller 16 support roller 17 intermediate transfer cleaning device 18 image forming means 20 roller charging means 21 exposure means 22 secondary transfer means 23 Roller 24 Secondary transfer belt 25 Fixing means 26 Fixing belt 27 Pressure belt 28 Sheet reversing device 30 Exposure means 32 Contact glass 33 First traveling body 34 Second traveling body 35 Imaging lens 36 Reading sensor 40 Developing means 41 Developing belt 42K developer container 42Y developer container 42M developer container 42C developer container 43K developer supply roller 43Y developer supply roller 43M developer supply roller 43C developer supply roller 44K developer roller 44Y developer roller 44M Developing roller 44C Developing roller 45K Black developing means (developing unit)
45Y yellow development means (development unit)
45M Magenta development means (development unit)
45C Cyan development means (development unit)
49 Registration roller 50 Intermediate transfer member 51 Roller 53 Manual feed path 54 Manual feed tray 55 Switching claw 56 Ejection roller 57 Ejection tray 58 Corona charger 59 Charging means 60 Cleaning means 61 Development means 62 Transfer charger 63 Photoconductor cleaning means 64 Removal Electric device 65 Developer on developing sleeve 68 Stir paddle 69 Partition plate 70 Static elimination means (static elimination lamp)
DESCRIPTION OF SYMBOLS 71 Toner density sensor 72 Developing sleeve 73 Doctor 75 Cleaning blade 76 Cleaning brush 77 Cleaning roller 78 Cleaning blade 79 Toner discharge auger 80 Drive apparatus 100 Image forming apparatus 101 Photoconductor 102 Charging means 103 Exposure means 104 Developing means 105 Transfer body 107 Cleaning means DESCRIPTION OF SYMBOLS 108 Transfer means 110 Belt type fixing device 120 Tandem type developing means 130 Document table 142 Paper feed roller 143 Paper bank 144 Paper feed cassette 145 Separation roller 146 Paper feed path 147 Conveyance roller 148 Paper feed path 150 Copier main body 200 Paper feed table 300 Scanner 400 Automatic document feeder (ADF)
L exposure

Claims (5)

In the carrier having a coating layer on the surface of the core material, the fibrous material is contained in the coating layer, the fibrous material is at least one selected from conductive polymers, and the fibrous material is an electrospinning method. A carrier characterized by being formed by . The carrier according to claim 1 is manufactured through a step of coating a fibrous material on a surface of a core material and a step of forming a coating layer on a mixture of the core material and the fibrous material obtained in the step. A career characterized by being. The method for producing a carrier according to claim 2 , wherein the coating step coats the fibrous material by an electrospinning method. A developer comprising the carrier according to claim 1 and a toner. An electrostatic latent image forming step for forming an electrostatic latent image on the electrostatic latent image carrier, and development for developing the electrostatic latent image using the developer according to claim 4 to form a visible image. An image forming method comprising: a step, a transfer step of transferring the visible image to a recording medium, and a fixing step of fixing the transferred image transferred to the recording medium.

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