JP6079311B2 - Electrostatic latent image development carrier - Google Patents

Description

  The present invention relates to a carrier for developing an electrostatic latent image used for developing an electrostatic latent image in electrophotography, electrostatic recording, electrostatic printing, and the like, a two-component developer, an image forming method using the developer, and a developer The present invention relates to a container, a process cartridge, a replenishing developer, and an image forming apparatus.

In electrophotographic image formation, a latent image is formed by an electrostatic charge on an image carrier such as a photoconductive substance, and a charged toner particle is attached to the electrostatic latent image to form a visible image. After that, the toner image is transferred to a recording medium such as paper and fixed to form an output image. In recent years, the technology of copying machines and printers using an electrophotographic system is rapidly expanding from monochrome to full color, and the full color market tends to expand.
Color image formation by full-color electrophotography generally reproduces all colors by laminating three color toners of three primary colors, yellow, magenta, and cyan, or four color toners with black added thereto. .

As a development method conventionally used in an image forming apparatus, a one-component development method in which a toner layer provided on a developer toner transport sleeve so that the layer thickness is regulated is transported to a development nip region for development. , A two-component development system that repeatedly forms and moves a magnetic brush composed of a carrier for holding toner and supplies it to an electrostatic latent image; a hybrid development system that combines both systems, that is, the layer thickness of the toner layer is regulated. A hybrid development system that cooperates with the layer thickness regulating means and the magnetic brush forming and moving means is used, but in order to obtain a uniform and clear full-color image with excellent color reproducibility, an electrostatic latent image is supported. The amount of toner on the body needs to be kept faithful to the electrostatic latent image.
When the amount of toner on the electrostatic latent image carrier fluctuates, the image density changes on the recording medium or the color tone of the image fluctuates.

The cause of the fluctuation of the toner amount on the electrostatic latent image bearing member includes the fluctuation of the toner charge amount. For example, as described in Patent Document 1, the previous image history is used as the next image in hybrid development. Has been reported to take over (ghost phenomenon).
The ghost phenomenon shown in Patent Document 1 is a problem unique to the hybrid development system, and the amount of toner on the toner carrier changes according to the toner consumption pattern of the immediately preceding image, so that the image density of the next image fluctuates. It is.

This is because in the hybrid developing system, a constant amount of toner is always supplied to the toner carrier, and thus the amount of toner on the toner carrier varies depending on the number of times the toner is supplied.
That is, when the previous image prints an image with low toner consumption, the amount of residual toner on the toner carrier is large, and after toner supply, the amount of toner on the toner carrier is further increased and the image density becomes high. On the other hand, after printing an image with high toner consumption, the amount of residual toner on the toner carrier is small, and after toner supply, the amount of toner on the toner carrier is small and the image density is low.
As described above, the ghost development in the hybrid development is a process in which when the toner is transferred from the two-component developer onto the toner carrier, the toner is developed and the toner is removed from the toner carrier in the immediately preceding image forming process. The toner is not developed, and the toner remains on the toner carrier. As a result, it is difficult to re-apply the toner amount evenly by overcoming this non-uniform toner amount. This is because the amount of toner on the toner carrier during the next image printing varies.

In order to solve these problems, for example, in Patent Documents 1 to 3, it is proposed that the residual toner on the toner carrier is scraped off by a scraper or a toner collection roll after development and before toner resupply. Patent Document 4 proposes a method of stabilizing the amount of toner on the toner carrier by collecting the residual toner on the toner carrier to a magnetic roll by a potential difference using between copies or between papers. Has been.
Further, as a countermeasure against a hysteresis phenomenon using a magnetic brush, Patent Document 5 proposes to collect and supply toner on the developing roll by setting a wide half-value width region of the magnetic flux density of the magnetic roll. Further, Patent Document 6 uses a non-spherical carrier as a carrier for a two-component developer, so that a charge is injected up to the carrier at the tip of the magnetic brush, and the substantial difference between the developer carrier and the toner carrier. By narrowing the interval, the amount of toner supplied to the toner carrier at one time is increased, and the toner is supplied up to the toner saturation amount on the toner carrier, so that the toner is carried without being affected by the history of the previous image. A method for keeping the amount of toner on the body constant has been proposed.

Further, as described in Patent Document 7, the ghost phenomenon has been reported in the two-component development method, but the inventors have developed the two-component development method for the reason why the ghost phenomenon occurs in the two-component development method. It is considered that poor drug withdrawal is the cause.
The two-component developer is peeled off by using an odd number of magnets in the developing sleeve and providing a pair of magnets with the same polarity at a position below the rotation axis of the developing sleeve to create a peeling region where the magnetic force is almost zero. In this method, the developer after the development is naturally dropped by using gravity and is peeled off.
However, when the amount of toner consumed in the previous image is generated, a counter charge is generated in the carrier, so that a mirror image force is generated between the carrier / developer carrier and the agent is not normally separated at the agent separation pole. This is a phenomenon in which the developing ability is lowered and the image density is reduced by transporting the agent having a reduced density again to the development area. That is, there is a problem that the density of the one round of the sleeve is normal, but the density becomes thin after the second round.
In order to solve these problems, for example, Patent Document 7 describes a configuration in which a scooping roll having a magnet inside is arranged in the vicinity of a peeling region on the developing sleeve, and the developer is peeled off with the magnetic force. Has been. The peeled developer is further pumped up by another scooping roll and then conveyed to a developer agitating chamber having a screw to readjust the toner concentration and charge the toner.

In view of the current state of the prior art, the object of the present invention is to develop a stable toner amount without being affected by the toner consumption history of the immediately preceding image, and to obtain a uniform image with excellent color reproducibility over a long period of time. It is an object to provide a carrier and a two-component developer and to provide an image forming method using the same.
Furthermore, it has a stable charge-imparting ability over a long period of time, excellent in both hardness and toughness (flexibility & elasticity) of the carrier coating film, excellent in wear resistance (scraping / peeling), and little change in carrier resistance. Carrier adhesion due to the exposure of the core material does not occur, charging fluctuation due to spent toner composition is small, and charging fluctuations are suppressed, image density fluctuations, background stains, toner scattering even in various usage environments The object is to provide a carrier that simultaneously satisfies the various characteristics of not causing in-flight contamination by the machine.

According to the present invention, first, in the carrier for an electrostatic charge image developer having a coating layer containing at least a binder resin and fine particles on the carrier core material, the core material is surface-oxidized, and the core of the carrier Provided is a carrier for developing an electrostatic latent image, wherein the material surface exposed area ratio is 0.1 to 5.0%.
Second, the electrostatic latent image developing carrier according to the first aspect is provided, wherein the core material has a volume resistivity (Log Ω · cm) of 6.0 or more and 7.0 or less.
Third, the carrier for electrostatic latent image developer according to the first or second aspect, wherein SF-2 of the carrier is in a range of 115 to 150.
Fourthly, the electrostatic latent image developer carrier according to any one of the first to third aspects, wherein the resin component in the coating layer contains at least a silicon resin.
Fifth, the resin component in the coating layer is a heat treatment of a copolymer containing at least an A component represented by the following general formula (A) and a B component represented by the following general formula (B). The electrostatic latent image developer carrier according to any one of the first to fourth aspects, comprising the obtained resin.

(In the formula, R ¹ represents a hydrogen atom or a methyl group, R ² represents an alkyl group having 1 to 4 carbon atoms, R ³ represents an alkyl group having 1 to 8 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, m Represents an integer of 1 to 8. A plurality of R ² may be the same or different, X represents 10 to 90 mol%, and Y represents 90 to 10 mol%.)

  Sixthly, the copolymer for electrostatic latent image developer according to the fifth aspect is provided, wherein the copolymer includes a copolymer represented by the following general formula (1).

(In the formula, R ¹ represents a hydrogen atom or a methyl group, R ² represents an alkyl group having 1 to 4 carbon atoms, R ³ represents an alkyl group having 1 to 8 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, m Represents an integer of 1 to 8. The plurality of R ¹ and R ² may be the same or different, X is 10 to 40 mol%, Y is 10 to 40 mol%, and Z is 30 to 80 Mol%, 60 mol% <Y + Z <90 mol%)

Seventhly, the electrostatic latent image developing carrier according to any one of the first to sixth aspects is provided, wherein the fine particles are conductive fine particles.
Eighth, the electrostatic latent image developing carrier according to any one of the first to seventh aspects, wherein the conductive fine particles have a volume average particle diameter of 50 to 800 nm.
Ninth, there is provided a developer for developing an electrostatic latent image comprising the carrier and the toner according to any one of the first to eighth aspects.
Tenth, the developer for developing an electrostatic latent image according to the ninth aspect is provided, wherein the toner is a color toner.
Eleventh, there is provided a developer-containing container comprising the developer according to the ninth or tenth aspect.
Twelfth, the step of forming an electrostatic latent image on the electrostatic latent image carrier, and the electrostatic latent image formed on the electrostatic latent image carrier is developed according to the ninth or tenth aspect. Forming a toner image using the agent, transferring the toner image formed on the electrostatic latent image carrier to a recording medium, and fixing the toner image transferred to the recording medium. An image forming method is provided.
Thirteenth, an electrostatic latent image carrier that forms an electrostatic latent image, and developing means that develops the formed electrostatic latent image into a toner image using the developer described in the ninth or tenth aspect. And an image forming apparatus comprising: a transfer unit that transfers the toner image to a recording medium; and a fixing unit that fixes the toner image transferred to the recording medium.
Fourteenth, at least a unit for developing the electrostatic latent image carrier and the electrostatic latent image formed on the electrostatic latent image carrier using the developer described in the ninth or tenth above. Provided is a process cartridge that is supported.
Fifteenth, a replenishment developer comprising the carrier and toner according to any one of the first to eighth aspects, wherein the mixing ratio of the carrier and toner is such that the toner is 2 to 1 part by mass of the carrier. A replenishment developer characterized by being 50 parts by weight is provided.

As will be understood from the following detailed and specific description, according to the present invention, a uniform image is developed that is not affected by the toner consumption history of the immediately preceding image, develops a stable toner amount, and has excellent color reproducibility. A carrier and a two-component developer that can be obtained over a long period of time are provided, and an image forming method using the carrier is provided.
Furthermore, it has a stable charge-imparting ability over a long period of time, excellent in both hardness and toughness (flexibility & elasticity) of the carrier coating film, excellent in wear resistance (scraping / peeling), and changes in carrier resistance. Less, carrier adhesion due to the influence of the core material exposure does not occur, charging fluctuation due to spent of the toner composition is small, and charging environmental fluctuation is suppressed, image density fluctuation, background stains, toner in various usage environments The excellent effect of providing a carrier that simultaneously satisfies the various characteristics of not causing in-flight contamination due to scattering is exhibited.

It is a figure explaining the resistance measuring cell of the volume specific resistance of the carrier core material in this invention, and the measuring method using the same. It is a figure explaining the powder specific resistance means and measuring method of electroconductive fine particles in this invention. 1 is a diagram showing a schematic configuration of an example of an image forming apparatus having a developer according to the present invention. FIG. 4 is a partially enlarged schematic explanatory diagram of the image forming apparatus shown in FIG. 3. It is a figure which shows schematic structure of the example of a process cartridge which has the developing agent of this invention. It is the figure which showed the normal image and the ghost image used as a subject in a longitudinal belt chart. FIG. 4 is a diagram illustrating a method for separating a carrier and a toner for measuring a charge amount of a developer according to the present invention.

The ghost phenomenon that is the subject of the present invention is different in the generation mechanism from any of the above ghost phenomena. The generation mechanism of the ghost phenomenon in the present invention is considered as follows although the details are not clear. The toner adheres to the developer carrying member according to the immediately preceding image history, and the toner development amount of the next image varies depending on the potential of the toner attached on the developer carrying member. That is, it is considered that the toner development amount of the next image varies depending on the immediately preceding image history.
Specifically, the toner adhesion to the developer carrying member occurs when the toner is developed on the developer carrying member because a bias is applied in the direction of the developing sleeve when not developing, and thus onto the developer carrying member. Since the developed toner has a potential, the development potential is increased by the potential of the toner on the developer carrier during printing, and the toner development amount increases. Further, since the toner developed on the developer carrier is consumed during development, the amount of toner on the developer carrier is not constant but varies depending on the history of the previous image. That is, at the time of development when the immediately preceding image is a non-image or immediately after the interval between the sheets, the toner is developed on the developer carrier, and the toner is attached on the developer carrier, The image density increases. On the other hand, when the immediately preceding image is an image having a large image area, the toner is consumed on the developer carrying member, so that the image density decreases.
As described above, the phenomenon to be solved by the present invention is a phenomenon in which the toner development amount on the developer carrying member fluctuates in response to the history of the immediately preceding image, and the density fluctuation of the next image appears due to the fluctuation. .

As a result of intensive studies on this problem, improvement was confirmed by setting the exposed area ratio on the surface of the core material to 0.1 to 5.0%. Details are not clear, but by using the core irregularities to create a low resistance part that is close to the core resistance locally, the toner developed on the developer carrier during non-development is less likely to be consumed during printing For this reason, it is considered that the toner amount on the developer carrying member is stable regardless of the immediately preceding image, and the uniformity of the image is obtained.
Therefore, the exposed area ratio of the core material of the carrier of the present invention is preferably 0.1 to 5.0%, and more preferably 0.1 to 2.0%. At this time, if the exposed area ratio on the surface of the core material is less than 0.1%, since the low resistance portion is small, the toner developed on the developer carrier is consumed during printing. On the other hand, if it exceeds 5.0%, the resistance of the entire carrier becomes low, so that the amount of toner developed on the developing carrier during non-image increases and image uniformity cannot be obtained.

The ratio of the exposed area ratio of the carrier core material to the maximum exposed area is measured by the following method.
That is, a reflected electron image is taken under the conditions of an applied voltage of 1 KV and a magnification of 1000 times using a Hitachi scanning electron microscope S-4200. This is taken into a TIFF image and converted to an image of only particles using Image-Pro Plus, an image processing software manufactured by Media Cybernetics, and then binarized to produce a white part (core exposed part) and a black part. And the area of the widest portion of each area and the white portion is measured. The result is calculated by the following formula to calculate a numerical value.

Core material exposed area ratio (%) = {area of white portion / (area of white portion + area of black portion)} × 100 (1)
Ratio (%) of maximum exposed area among exposed portions of core material = {area of widest portion in white portion / (area of white portion + area of black portion)} × 100 (2)

  Further, as the core material of the carrier of the present invention, it is preferable to use a surface oxidized material. Here, as a meaning of using a core material whose surface is oxidized, in a carrier whose exposed area ratio on the surface of the core material is 0.1 to 5.0%, a core material that is not surface-oxidized is used. This is because carrier adhesion occurs. Although the details are not clear, it is considered that the core material in the exposed portion has a high resistance, thereby preventing the occurrence of carrier adhesion.

  The carrier core material of the present invention preferably has a volume resistivity (Log Ω · cm) of 6.0 or more and 7.0 or less. When the volume resistivity (Log Ω · cm) is less than 6.0, carrier adhesion occurs due to the low resistance of the exposed portion of the core material, and when it is 7.0 or more, the core material is partially exposed. A local low resistance due to the ghost cannot be created, and a ghost phenomenon occurs.

The volume resistivity referred to in this specification is measured as follows. That is, as shown in FIG. 1, a carrier 13 is filled in a cell 11 made of a fluororesin container containing an electrode 12a and an electrode 12b each having a distance between electrodes of 2 mm and a surface area of 2 × 4 cm. Using the PTM-1 type, a tapping operation is performed for 1 minute at a tapping speed of 30 times / min.
A DC voltage of 1000 V was applied between the two electrodes, and the DC resistance was measured by a high resistance meter 4329A (4329A + LJK5HVLVWDQFH 0HWHU; manufactured by Yokogawa Hewlett-Packard Co., Ltd.) to obtain the electrical resistivity R (Ω · cm), and LogR (Ω · cm ) Is calculated.

In the core material of the present invention, SF-2 is preferably larger than SF-1. When SF-1 is larger than SF-2, the shape of the entire carrier is more greatly affected than the core exposed portion due to the unevenness, so that it is difficult to obtain a local resistance effect.
The core shape factors SF1 and SF2 mean the following.
SF1 and SF2 indicating the shape factor are, for example, 100 carrier particle images that have been magnified 300 times using FE-SEM (S-800) manufactured by Hitachi, Ltd., and the image information is obtained via the interface. For example, it is introduced into an image analysis apparatus (Luzex AP) manufactured by Nireco and analyzed, and values obtained by the following calculation formulas (3) and (4) are defined as shape coefficients SF1 and SF2.

SF1 = (L ² / A) × (π / 4) × 100 Formula (3)
SF2 = (P ² / A) × (1 / 4π) × 100 Formula (4)
(In the above formula, L is the absolute maximum length of the particle (the length of the circumscribed circle), P is the peripheral length of the particle, and A is the projected area of the particle.)

    The shape factor SF1 indicates the degree of roundness of the particles, and the shape factor SF2 indicates the degree of unevenness of the particles. The value of SF1 increases as the distance from the circle (spherical) increases. When the unevenness on the surface becomes severe, the value of SF2 also increases.

  Further, the amount of fine particles of the carrier core material of the present invention is more preferably 20% or less at a ratio of 26 μm or less for carrier adhesion.

  Although it does not specifically limit as a core material of the carrier said by this invention, Mn type ferrite, Mn-Mg type ferrite, Mn-Mg-Sr ferrite, etc. are preferable.

  The carrier core material manufacturing method referred to in the present invention is obtained by pulverizing, mixing, and calcining each compound as a raw material, and then pulverizing, mixing, and granulating again. It is preferable to include a step of performing surface oxidation treatment after firing and further crushing and classification.

The surface oxidation treatment can be performed by performing heat treatment at, for example, 300 to 800 ° C. using a general rotary electric furnace, batch electric furnace or the like.
In order to uniformly oxidize the surface, it is preferable to use a rotary electric furnace.

  When the core particles are coated with the resin coating layer, it is important to coat the core particles so as to leave the irregularities of the core particles, and SF2 after coating is in the range of 115 to 150, more preferably in the range of 120 to 145. Is desirable. When the SF2 of the core material particles is less than 120, it is easy to cover the convex portions of the core material, and it becomes difficult to make a local low resistance. When the core particle SF2 exceeds 160, the voids in the core material particle are increased, the strength of the core material particle is weakened, and the magnetic force of the core material particle is decreased. It becomes easy to cause the carrier adhesion phenomenon that the carrier adheres to the body. Furthermore, when the SF2 is 160 or more, the core material is exposed excessively when used in a developing machine for a long time in actual use, and the change in the initial resistance value and the resistance value after use becomes large. The amount of toner on the carrier and how it is loaded change, and the image quality is not stable.

  The carrier of the present invention contains the binder resin in an amount of 2.8 to 4.6 parts by weight with respect to 100 parts by weight of the core material. 2 is preferably 115 to 150, more preferably 3.0 to 4.0 parts by weight. If the amount is less than 2.8 parts by weight, the coating layer is thin, so when a large amount of printing is performed on a high-stress machine, the exposure of the core material increases, the resistance decreases, and image uniformity is obtained. Absent. Further, since the exposure of the core material increases, the charging stability at the time of printing the low image area ratio is also deteriorated. If it exceeds 4.6 parts by weight, if the resin film is scraped off by a large amount of printing in a high-stress machine, the volume of the developer is greatly reduced, so that the agent may be depleted on the developing sleeve. is there.

As the binder resin for the carrier of the present invention, those containing at least a silicon resin are preferable. The improvement effect is remarkable because the binder resin of the carrier is at least a silicon resin.
This is because the toner component is difficult to spend due to the low surface energy of silicon resin.
As used herein, the term “silicon resin” refers to all commonly known silicon resins, such as straight silicon consisting only of organosilosan bonds, and silicon resins modified with alkyd, polyester, epoxy, acrylic, urethane, etc. However, it is not limited to this.

  For example, taking a commercial product as an example, examples of the straight silicone resin include KR271, KR255, KR152 manufactured by Shin-Etsu Chemical, SR2400, SR2406, SR2410 manufactured by Toray Dow Corning Silicon Co., etc. In this case, it is possible to use the silicon resin alone, but it is also possible to simultaneously use other components that undergo a crosslinking reaction, charge amount adjusting components, and the like. Further, as modified silicone resin, KR206 (alkyd modified), KR5208 (acryl modified), ES1001N (epoxy modified), KR305 (urethane modified) manufactured by Shin-Etsu Chemical, SR2115 (epoxy modified) manufactured by Toray Dow Corning Silicon Co., Ltd. , SR2110 (alkyd modified) and the like.

In the present invention, it is preferable that the coating film further contains a silane coupling agent because the stability of the carrier over time is improved and the durability can be improved.
The silane coupling agent is not particularly limited, and examples thereof include methyltrimethoxysilane, methyltriethoxysilane, octyltrimethoxysilane, and the like, but aminosilane is preferable.
The aminosilane is not particularly limited, but the following chemical formula:
H ₂ N (CH ₂ ) ₃ Si (OCH ₃ ) ₃ ,
H ₂ N (CH ₂ ) ₃ Si (OC ₂ H ₅ ) ₃ ,
H ₂ N (CH ₂ ) ₃ Si (CH ₃ ) ₂ (OC ₂ H ₅ ),
_{H 2 N (CH 2) 3} Si (CH 3) (OC 2 H 5) 2,
H ₂ N (CH ₂ ) ₂ (NH) (CH ₂ ) Si (OCH ₃ ) ₃ ,
H ₂ N (CH ₂ ) ₂ (NH) (CH ₂ ) ₃ Si (CH ₃ ) (OCH ₃ ) ₂ ,
H ₂ N (CH ₂ ) ₂ (NH) (CH ₂ ) ₃ Si (OCH ₃ ) ₃ ,
_{(CH 3) 2 N (CH} 2) 3 Si (CH 3) (OC 2 H 5) 2,
(C ₄ H ₉ ) ₂ N (CH ₂ ) ₃ Si (OCH ₃ ) ₃
The compound represented by these is mentioned.

  The content of aminosilane in the coating layer is preferably 0.001 to 30% by mass, and more preferably 0.001 to 15% by mass. When the content is less than 0.001% by mass, the effect of improving the durability of the carrier may be insufficient. When the content exceeds 30% by mass, conductive particles and inorganic particles are retained in the coating layer. May be difficult to do.

  The carrier for an electrostatic latent image developer of the present invention comprises magnetic core material particles and a coating layer that coats the surface of the core material particles, and contains conductive fine particles in the coating layer. The resin component is crosslinked by hydrolyzing a copolymer of the following general formula (2) obtained by radical copolymerization of the monomer A component and the monomer B component, generating a silanol group, and condensing using a catalyst. It is preferable to use a carrier for developing an electrostatic latent image obtained by heating after coating.

(Here, in the general formula (2), R ¹ , m, R ² , R ³ , X, and Y are as follows.)
R ¹ : a hydrogen atom or a methyl group,
m: alkylene group such as methylene group having 1 to 8 carbon atoms, ethylene group, propylene group, butylene group,
R ² : an alkyl group such as a methyl group having 1 to 4 carbon atoms, an ethyl group, a propyl group, an isopropyl group, and a butyl group,
R ³ : Alkyl group such as methyl group having 1 to 8 carbon atoms, ethyl group, propyl group, isopropyl group and butyl group, or alkoxy group having 1 to 4 carbon atoms such as methoxy group, ethoxy group, propoxy group and butoxy group. Group.

A component:

(In the previous formula,
R ¹ : a hydrogen atom or a methyl group,
m: alkylene group such as methylene group having 1 to 8 carbon atoms, ethylene group, propylene group, butylene group,
R ^2: an aliphatic hydrocarbon group having 1 to 4 carbon atoms, a methyl group, an ethyl group, a propyl group, and butyl group,
Represents. )

In A component, it is X = 10-90 mol%, More preferably, it is 30-70 mol%.
The A component has an atomic group having a large number of methyl groups in the side chain and tris (trimethylsiloxy) silane. When the ratio of the A component to the entire resin increases, the surface energy decreases, and the resin component of the toner. , Adhesion of wax components and the like is reduced. When the A component is less than 10 mol%, a sufficient effect cannot be obtained, and the adhesion of the toner component increases rapidly. On the other hand, if it exceeds 90 mol%, component B and component C decrease, crosslinking does not proceed, toughness is insufficient, adhesion between the core material and the resin layer decreases, and the durability of the carrier coating deteriorates. .

R ² is an alkyl group having 1 to 4 carbon atoms, and examples of such a monomer component include a tris (trialkylsiloxy) silane compound represented by the following formula (wherein Me is a methyl group, Et is an ethyl group and Pr is a propyl group).

_{CH 2 = CMe-COO-C} 3 H 6 -Si (OSiMe 3) 3
_{CH 2 = CH-COO-C} 3 H 6 -Si (OSiMe 3) 3
_{CH 2 = CMe-COO-C} 4 H 8 -Si (OSiMe 3) 3
_{CH 2 = CMe-COO-C} 3 H 6 -Si (OSiEt 3) 3
_{CH 2 = CH-COO-C} 3 H 6 -Si (OSiEt 3) 3
_{CH 2 = CMe-COO-C} 4 H 8 -Si (OSiEt 3) 3
_{CH 2 = CMe-COO-C} 3 H 6 -Si (OSiPr 3) 3
_{CH 2 = CH-COO-C} 3 H 6 -Si (OSiPr 3) 3
_{CH 2 = CMe-COO-C} 4 H 8 -Si (OSiPr 3) 3

  The production method of the component A is not particularly limited, but a method of reacting tris (trialkylsiloxy) silane with allyl acrylate or allyl methacrylate in the presence of a platinum catalyst, or a carboxylic acid described in JP-A-11-217389 It can be obtained by a method of reacting methacryloxyalkyltrialkoxysilane and hexaalkyldisiloxane in the presence of an acid catalyst.

Component B: (Crosslinking component)

(In the previous formula,
R ¹ : a hydrogen atom or a methyl group,
m: alkylene group such as methylene group having 1 to 8 carbon atoms, ethylene group, propylene group, butylene group,
R ^2: an aliphatic hydrocarbon group having 1 to 4 carbon atoms, a methyl group, an ethyl group, a propyl group, and butyl group,
R ³ : an alkyl group having 1 to 8 carbon atoms (methyl group, ethyl group, propyl group, butyl group, etc.) or an alkoxy group having 1 to 4 carbon atoms (methoxy group, ethoxy group, propoxy group, butoxy group), Represent. )
That is, the component B is a radically polymerizable bifunctional or trifunctional silane compound, and Y = 10 to 90 mol%, more preferably 30 to 70 mol%.

If the B component is less than 10 mol%, sufficient toughness cannot be obtained. On the other hand, when it exceeds 90 mol%, the coating becomes hard and brittle, and film scraping tends to occur. Moreover, environmental characteristics deteriorate. It is also conceivable that a large number of hydrolyzed crosslinking components remain as silanol groups, deteriorating environmental characteristics (humidity dependency).
Examples of such component B include 3-methacryloxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltriethoxysilane, and 3-methacryloxypropylmethyl. Examples include dimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltri (isopropoxy) silane, and 3-acryloxypropyltri (isopropoxy) silane.

In the present invention, the A component and the B component may be added to the acrylic compound (monomer) as a C component.
Examples of such a C component include a copolymer represented by the following general formula (1).

(In the formula, R ¹ , m, R ² , R ³ , X, Y, and Z are as follows.)
R ¹ : a hydrogen atom or a methyl group,
m: an alkylene group having 1 to 8 carbon atoms,
R ² : an alkyl group having 1 to 4 carbon atoms,
R ³ is an alkyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms,
Represents. )

A component:

X = 10 to 40 mol%.

B component:

Y = 10 to 40 mol%.

C component:

Z = 30 to 80 mol%, and 60 mol% <Y + Z <90 mol%.

  The C component imparts flexibility to the coating and improves the adhesion between the core material and the coating. However, if the C component is less than 30 mol%, sufficient adhesion cannot be obtained. If it exceeds 80 mol%, since either the X component or the Y component is 10 mol% or less, it becomes difficult to achieve both water repellency, hardness and flexibility (film scraping) of the carrier coating.

  As the acrylic compound (monomer) of component C, acrylic acid ester and methacrylic acid ester are preferable. Specifically, methyl methacrylate, methyl acrylate, ethyl methacrylate, ethyl acrylate, butyl methacrylate, butyl acrylate, 2- (dimethylamino) ) Ethyl methacrylate, 2- (dimethylamino) ethyl acrylate, 3- (dimethylamino) propyl methacrylate, 3- (dimethylamino) propyl acrylate. Of these, alkyl methacrylate is preferable, and methyl methacrylate is particularly preferable. One of these compounds may be used alone, or a mixture of two or more may be used.

Japanese Patent No. 3691115 is known as a technique for improving durability by crosslinking a coating. Japanese Patent No. 3691115 discloses radical copolymerization of a magnetic particle surface with an organopolysiloxane having at least a terminal vinyl group and at least one functional group selected from the group consisting of hydroxyl group, amino group, amide group and imide group. Is a carrier for developing an electrostatic image characterized in that a copolymer with a photopolymerizable monomer is coated with a thermosetting resin crosslinked with an isocyanate compound. The current situation is that it has not been obtained.
The reason for this is not clear enough, but in the case of a thermosetting resin obtained by crosslinking the above-mentioned copolymer with an isocyanate compound, the isocyanate in the copolymer resin is understood from the structural formula. There are few functional groups per unit weight which reacts (crosslinks) with the compound, and a two-dimensional or three-dimensional dense crosslinked structure cannot be formed at the crosslinking point. Therefore, if it is used for a long time, the film is easily peeled off or scraped off (the abrasion resistance of the film is small), and it is assumed that sufficient durability is not obtained.

When the film is peeled off or scraped off, the image quality changes due to a decrease in carrier resistance and carrier adhesion occurs. Also, peeling or scraping of the coating reduces the fluidity of the developer and causes a decrease in the amount of pumping, which causes a decrease in image density, contamination when toner is increased, and toner scattering.
The resin of the present invention is a copolymer resin having a large number (two to three times more per unit weight) of bifunctional or trifunctional crosslinkable functional groups (points) than the resin unit weight. Further, since this is further cross-linked by condensation polymerization, it is considered that the coating film is extremely tough and difficult to scrape, and high durability is achieved.

  Further, it is presumed that the aging stability of the coating is maintained because the crosslinking by the siloxane bond of the present invention has a higher binding energy and is more stable against heat stress than the crosslinking by the isocyanate compound.

  The coating layer of the present invention preferably contains conductive fine particles in order to adjust the volume resistivity of the carrier. Moreover, it is preferable that the volume average particle diameter of electroconductive fine particles is 50-800 nm. If the volume average particle size is less than 50 nm, resin or conductive fine particles adhere to the exposed core material, making it difficult to expose the core material. If it exceeds 800 nm, it will be difficult to hold the fine particles, the film will be scraped and the resistance will be reduced, and image uniformity will not be obtained.

  As the conductive fine particles of the present invention, a filler formed by forming a layer of tin dioxide or indium oxide on a substrate such as aluminum oxide, titanium dioxide, zinc oxide, silicon dioxide, barium sulfate, zirconium oxide, carbon black, etc. can be used. Aluminum oxide, titanium dioxide and barium sulfate are preferred.

The volume average particle diameter of the conductive fine particles is measured with an automatic particle size distribution analyzer CAPA-700 (manufactured by Horiba Seisakusho). As a pretreatment for the measurement, 300 ml of a toluene solution is added to 30 ml of aminosilane (SH6020: manufactured by Toray Dow Corning Silicone) in a juicer mixer.
Add 6.0 g of sample, set mixer rotation speed to low and disperse for 3 minutes. An appropriate amount of the dispersion is added to 500 ml of a toluene solution prepared in advance in a 1000 ml beaker and diluted. The diluting solution is continuously stirred with a homogenizer. This diluted solution is measured with an ultracentrifugal automatic particle size distribution analyzer CAPA-700.

[Measurement condition]
Rotation speed: 2000rpm
Maximum particle size: 2.0 μm
Minimum particle size: 0.1 μm
Particle size interval: 0.1 μm
Dispersion medium viscosity: 0.59 mPa · s
Dispersion medium density: 0.87 g / cm ³
Particle density: For the density of inorganic fine particles, the true specific gravity value measured using a dry automatic bulk density meter Accupic 1330 (manufactured by Shimadzu Corporation) is input.

The carrier of the present invention preferably has a powder specific resistance of conductive fine particles of 2 (Log Ω · cm) or less. If the powder specific resistance is larger than 2, the resistance of the entire carrier cannot be adjusted sufficiently.
The powder specific resistance is measured by the following method. (See FIG. 2). Take 5 g of sample with a pan balance, put a steel electrode on the bottom of a 1 inch inner diameter PVC tube, and place the sample in the PVC tube. Next, apply a steel electrode to the top of the PVC pipe. A 2 mm thick Teflon (registered trademark) plate is laid on the top and bottom of the electrode, and a load of 10 kg / cm ² is applied by a hydraulic gauge scale with a hydraulic press. An LCR meter (Yokogawa-HEWLETT-PACKARD 4261A or a measuring instrument having equivalent or better performance) is connected in a state where the pressure is 10 kg / cm ² . The resistance r (Ω) immediately after the connection is read and the total length L (cm) is measured with a caliper to calculate the powder specific resistance (Ω · cm). The calculation formula is shown in the following formula.

Specific resistance of powder (Ω · cm) = {(2.54 / 2) 2 × π} × r / (L-11.35) (5)
r: resistance immediately after connection L: full length when the sample is filled 11.35: full length when the sample is not filled

  Moreover, it is preferable that the weight average particle diameter of the carrier in this invention is 20 micrometers or more and 65 micrometers or less. When the weight average particle size is less than 20 μm, problems such as carrier adhesion occur because the uniformity of the particles is lowered and a technique for fully utilizing on the machine side has not been established. On the other hand, if it exceeds 65 μm, the reproducibility of image details is poor and a fine image cannot be obtained.

  The weight average particle diameter of the carrier can be measured using an SRA type of a Microtrac particle size analyzer (manufactured by Nikkiso Co., Ltd.). What was performed by the range setting of 0.7 micrometer or more and 125 micrometers or less is used. Further, methanol is used for the dispersion, and the refractive index is set to 1.33, and the refractive indexes of the carrier and the core material are set to 2.42.

Volume resistivity of the carrier in the present invention preferably has a volume resistivity of at most 1 × 10 ⁸ Ω · cm or more ^{1 × 10 15 Ω · cm,} 1 × 10 8 Ω · cm or more 1 × ^{10 12} Ω · More preferably, it is not more than cm. This is because when the volume resistivity is less than 1 × 10 ⁸ Ω · cm, the amount of toner developed on the developing carrier during non-image increases, and image uniformity cannot be obtained. On the other hand, when the volume resistivity exceeds 1 × 10 ¹⁵ Ω · cm, the toner developed on the developer carrier is consumed during printing, and image uniformity cannot be obtained.

  By applying the carrier of the present invention to a replenishment developer composed of a carrier and a toner and applying it to an image forming apparatus that forms an image while discharging excess developer in the developing device, a stable image can be obtained over a very long period of time. Quality is obtained. That is, the deteriorated carrier in the developing device and the non-deteriorated carrier in the replenishing developer are replaced, and the charge amount is kept stable over a long period of time, so that a stable image can be obtained. This method is particularly effective when printing a large image area. When printing a large image area, carrier charge deterioration due to toner spent on the carrier is the main carrier deterioration. However, when this method is used, the carrier replenishment amount increases when the image area is large, and the deteriorated carrier is replaced. Increases frequency. Thereby, a stable image can be obtained for an extremely long period of time.

  The mixing ratio of the replenishment developer is preferably 2 to 50 parts by mass of toner with respect to 1 part by mass of the carrier. When the amount of toner is less than 2 parts by mass, the amount of replenishment carrier is excessive, the carrier is excessively supplied, and the carrier concentration in the developing device becomes too high, so that the charge amount of the developer tends to increase. Further, as the developer charge amount increases, the developing ability decreases and the image density decreases. On the other hand, if the amount exceeds 50 parts by mass, the carrier ratio in the replenishment developer decreases, so that the replacement of carriers in the image forming apparatus decreases, and the effect on carrier deterioration cannot be expected.

[toner]
As the binder resin used in the toner of the present invention, known resins can be used. For example, styrene such as polystyrene, poly-p-styrene, and polyvinyltoluene, and homopolymers thereof, styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene- Methyl acrylate copolymer, Styrene-ethyl acrylate copolymer, Styrene-methacrylic acid copolymer Corp., Styrene-methyl acrylate copolymer, Styrene-ethyl acrylate copolymer, Styrene-methacrylic acid Butyl copolymer, styrene-α-chloromethacrylic acid methyl copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, Styrene-isopropyl copolymer, styrene-male Styrene copolymers such as acid ester copolymer, polythyme methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polyester, polyurethane, epoxy resin, polyvinyl butyral, polyacrylic acid resin, rosin, modified Rosin, terpene resin, phenol resin, aliphatic or aromatic hydrocarbon resin, aromatic petroleum resin, or the like can be used alone or in combination.
And as a binder resin for pressure fixing, a well-known thing can be mixed and used. For example, polyolefin such as low molecular weight polyethylene and low molecular weight polypropylene, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, styrene-methacrylic acid copolymer, ethylene-methacrylic acid ester copolymer, ethylene-chlorinated Vinyl copolymer, ethylene-vinyl acetate copolymer, olefin copolymer such as ionomer resin, epoxy resin, polyester resin, styrene-butadiene copolymer, polyvinylpyrrolidone, methyl vinyl ether-maleic anhydride, maleic acid modified phenol resin Phenol-modified terpene resins and the like can be used alone or in combination, but are not limited thereto.

  Further, the toner used in the present invention may contain a fixing aid in addition to the binder resin, the colorant, and the charge control agent. Accordingly, it can be used in a fixing system in which toner fixing prevention oil is not applied to the fixing roll, so-called oilless system. Known fixing aids can be used. For example, polyolefins such as polyethylene and polypropylene, fatty acid metal salts, fatty acid esters, paraffin waxes, amide waxes, polyhydric alcohol waxes, silicone varnishes, carnauba waxes and ester waxes can be used, but are not limited thereto.

As the colorant used in the toner such as the color toner of the present invention, known pigments and dyes capable of obtaining yellow, magenta, cyan, and black toners can be used, and are not limited to those listed here. Examples of yellow pigments include cadmium yellow, mineral fast yellow, nickel titanium yellow, navel yellow, naphthol yellow S, Hansa Yellow G, Hansa Yellow 10G, Benzidine Yellow GR, Quinoline Yellow Lake, Permanent Yellow NCG and Tartrazine Lake. Can be mentioned.
Examples of the orange pigment include molybdenum orange, permanent orange GTR, pyrazolone orange, vulcan orange, indanthrene brilliant orange RK, benzidine orange G, and indanthrene brilliant orange GK.
Examples of red pigments include Bengala, Cadmium Red, Permanent Red 4R, Resol Red, Pyrazolone Red, Watching Red Calcium Salt, Lake Red D, Brilliant Carmine 6B, Eosin Lake, Rhodamine Lake B, Alizarin Lake, Brilliant Carmine 3B.
Examples of purple pigments include fast violet B and methyl violet lake.
Examples of blue pigments include cobalt blue, alkali blue, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, phthalocyanine blue partially chlorinated, first sky blue, and indanthrene blue BC.
Examples of the green pigment include chrome green, chromium oxide, pigment green B, and malachite green lake.
Examples of black pigments include azine dyes such as carbon black, oil furnace black, channel black, lamp black, acetylene black, and aniline black, metal salt azo dyes, metal oxides, and composite metal oxides.
Moreover, these colorants can use 1 type (s) or 2 or more types.

  The toner such as the color toner of the present invention may contain a charge control agent in the toner as necessary. For example, the color toner of the present invention can contain a charge control agent in the toner as needed. For example, nigrosine, an azine dye containing an alkyl group having 2 to 16 carbon atoms (Japanese Patent Publication No. 42-1627), a basic dye (for example, CI Basic Yellow 2 (CI 41000), CI Basic Yellow 3, C.I.Basic Red 1 (C.I. 45160), C.I.Basic Red 9 (C.I. 42500), C.I.Basic Violet 1 (C.I. 42535), C I. Basic Violet 3 (C.I. 42555), C. I. Basic Violet 10 (C.I. 45170), C.I.Basic Violet 14 (C.I. 42510), C.I.Basic Blueet 1 (C.I. 42025), C.I.Basic Blue 3 (C.I.51005), C.I. ascii blue 5 (C.I. 42140), C.I.Basic Blue 7 (C.I.42595), C.I.Basic Blue 9 (C.I.522015), C.I.Basic Blue 24 (C. CI Basic Blue 25 (C.I.52025), C.I.Basic Blue 26 (C.I.44045), C.I.Basic Green 1 (C.I.42040), Lake pigments of these basic dyes, such as CI Basic Green 4 (CI 42000), CI Solvent Black 8 (CI 26150), benzoylmethyl hexadecyl ammonium chloride, decyltrimethyl chloride Quaternary ammonium salts such as dibutyl or dioctyl Dialkyl tin compounds, dialkyl tin borate compounds, guanidine derivatives, vinyl polymers containing amino groups, polyamine resins such as condensation polymers containing amino groups, Japanese Patent Publication No. 41-20153, Japanese Patent Publication No. 43-27596 A metal complex salt of a monoazo dye described in JP-B-44-6397 and JP-B-45-26478, salicylic acid described in JP-B-55-42752, JP-B-59-7385, Examples include dialkyl salicylic acid, naphthoic acid, dicarboxylic acid metal complexes such as Zn, Al, Co, Cr, and Fe, sulfonated copper phthalocyanine pigments, organic boron salts, fluorine-containing quaternary ammonium salts, calixarene compounds, and the like. . Naturally, color toners other than black should avoid the use of charge control agents that impair the target color, and white metal salts of salicylic acid derivatives are preferably used.

As for the external additive, the transferability and durability are further improved by externally adding inorganic fine particles such as silica, titanium oxide, alumina, silicon carbide, silicon nitride, boron nitride and resin fine particles to the base toner particles. This effect can be obtained by covering the wax that lowers transferability and durability with these external additives and reducing the contact area due to the toner surface being covered with fine particles. The surface of these inorganic fine particles is preferably subjected to a hydrophobic treatment, and metal oxide fine particles such as silica and titanium oxide subjected to the hydrophobic treatment are preferably used. As the resin fine particles, polymethyl methacrylate or polystyrene fine particles having an average particle diameter of about 0.05 to 1 μm obtained by a soap-free emulsion polymerization method are suitably used.
In addition, the combination of hydrophobized silica and hydrophobized titanium oxide increases the amount of hydrophobized titanium oxide externally added compared to the amount of hydrophobized silica externally charged. The toner can also be excellent in stability. In combination with the inorganic fine particles described above, silica having a specific surface area of 20 to 50 m / g or resin fine particles having an average particle diameter of 1/100 to 1/8 of the average particle diameter of the toner can be used. The durability can be improved by externally adding an external additive having a particle size larger than that of the additive to the toner.
This is because the metal oxide particles externally added to the toner tend to be embedded in the base toner particles in the process where the toner is mixed and stirred with the carrier in the developing device, charged, and used for development. This is because it is possible to prevent the metal oxide fine particles from being embedded by externally adding an external additive having a particle size larger than that of the oxide fine particles to the toner.
The above-mentioned inorganic fine particles and resin fine particles are contained (internally added) in the toner, but the effect is reduced as compared with the case of external addition, but the effect of improving transferability and durability can be obtained and the pulverization property of the toner can be improved. Can do. In addition, since external addition and internal addition can be used together to suppress embedding of externally added fine particles, excellent transferability can be stably obtained and durability can be improved.

  In addition, the following are mentioned as a typical example of the hydrophobization processing agent used here. Dimethyldichlorosilane, trimethylchlorosilane, methyltrichlorosilane, allyldimethyldichlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, p-chloroethyltrichlorosilane, Chloromethyldimethylchlorosilane, chloromethyltrichlorosilane, p-chlorophenyltrichlorosilane, 3-chloropropyltrichlorosilane, 3-chloropropyltrimethoxysilane, vinyltriethoxysilane, vinylmethoxysilane, vinyl-tris (β-methoxyethoxy) ) Silane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, divinyldichlorosilane, dimethylvinylchlorosilane, octyl Trichlorosilane, decyl-trichlorosilane, nonyl-trichlorosilane, (4-t-propylphenyl) -trichlorosilane, (4-t-butylphenyl) -trichlorosilane, diventyl-dichlorosilane, dihexyl-dichlorosilane, dioctyl-dichlorosilane, dinonyl -Dichlorosilane, didecyl-dichlorosilane, didodecyl-dichlorosilane, dihexadecyl-dichlorosilane, (4-t-butylphenyl) -octyl-dichlorosilane, dioctyl-dichlorosilane, didecenyl-dichlorosilane, dinonenyl-dichlorosilane, di-2-ethylhexyl-dichlorosilane, di- 3,3-dimethylbenthyl-dichlorosilane, trihexyl-chlorosilane, trioctyl-chlorosilane, tridecyl-chlorosilane Dioctyl-methyl-chlorosilane, octyl-dimethyl-chlorosilane, (4-t-propylphenyl) -diethyl-chlorosilane, octyltrimethoxysilane, hexamethyldisilazane, hexaethyldisilazane, diethyltetramethyldisilazane, hexaphenyldisilazane , Hexatolyl disilazane and the like. In addition, titanate coupling agents and aluminum coupling agents can also be used. In addition, as an external additive for the purpose of improving cleaning properties, a lubricant such as a fatty acid metal salt or a fine particle of polyvinylidene fluoride can be used in combination.

  Conventionally known methods such as a pulverization method and a polymerization method can be applied to the toner production method of the present invention. For example, in the case of the pulverization method, as a device for kneading the toner, a batch type two roll, a Banbury mixer or a continuous twin screw extruder, for example, KTK type twin screw extruder manufactured by Kobe Steel, TEM manufactured by Toshiba Machine Co., Ltd. Type twin screw extruder, KCK twin screw extruder, Ikegai Iron Works PCM type twin screw extruder, Kurimoto Iron Works KEX type twin screw extruder, continuous single screw kneader, for example Buss Co-kneader is preferably used. The melt-kneaded product obtained as described above is cooled and then pulverized. For pulverization, for example, coarsely pulverized using a hammer mill, a funnel plex or the like, and further, a fine pulverizer using a jet stream or mechanical pulverization A machine can be used. The pulverization is desirably performed so that the average particle diameter is 3 to 15 μm. Further, the pulverized product is preferably adjusted in particle size to 5 to 20 μm by a wind classifier or the like. Subsequently, the external additive is externally added to the base toner. The base toner and the external additive are mixed and stirred using a mixer, and the external additive is crushed and coated on the toner surface. At this time, it is important in terms of durability that external additives such as inorganic fine particles and resin fine particles are uniformly and firmly attached to the base toner. The above is only an example, and the present invention is not limited to this.

[Image forming apparatus, process cartridge]
FIG. 3 shows a schematic configuration of an example of an image forming apparatus equipped with a process cartridge having a developing unit using the developer of the present invention.
FIG. 5 shows the entire process cartridge, which includes a photoconductor, a charging unit, a developing unit, and a cleaning unit.
In the present invention, among the constituent elements such as the above-described photoreceptor, charging means, developing means, and cleaning means, the developing means using the developer of the present invention and one or more other means are used as a process cartridge. The process cartridge is configured so as to be integrally connected, and is configured to be detachable from a main body of an image forming apparatus such as a copying machine or a printer.

  In an image forming apparatus equipped with a process cartridge having developing means using the developer of the present invention, the photosensitive member is rotationally driven at a predetermined peripheral speed. In the rotation process, the photosensitive member receives a uniform positive or negative electric potential on its peripheral surface by the charging means, and then receives image exposure light from an image exposure means such as slit exposure or laser beam scanning exposure. An electrostatic latent image is sequentially formed on the peripheral surface of the body, and the formed electrostatic latent image is then developed with toner by a developing unit, and the developed toner image is transferred between the photosensitive member and the transfer unit from the paper feeding unit. Then, the image is sequentially transferred to the transfer material fed in synchronization with the rotation of the photosensitive member by the transfer means. The transfer material that has received the image transfer is separated from the surface of the photosensitive member, introduced into the image fixing means, and fixed on the image, and printed out as a copy (copy). The surface of the photoreceptor after the image transfer is cleaned by removing the transfer residual toner by the cleaning means, and after being further neutralized, it is repeatedly used for image formation.

  The apparatus shown in FIG. 3 is a tandem type color image forming apparatus (hereinafter, this apparatus may be referred to as “image forming apparatus A”). The tandem image forming apparatus includes a copying apparatus main body 110, a paper feed table 200, a scanner 300, and an automatic document feeder (ADF) 400. 4 is a partially enlarged schematic explanatory view of the image forming apparatus shown in FIG.

The copying apparatus main body 110 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 be rotated clockwise in FIG. 3. An intermediate transfer member cleaning device 17 for removing residual toner on the intermediate transfer member 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 is a tandem type in which four image forming units 18 of yellow, cyan, magenta, and black are arranged to face each other along the conveyance direction. A developing device 120 is disposed. An exposure device 21 is disposed in the vicinity of the tandem developing device 120.
A secondary transfer device 22 is disposed on the side of the intermediate transfer member 50 opposite to the side on which the tandem developing device 120 is disposed. In the secondary transfer device 22, a secondary transfer belt 24 that is an endless belt is stretched around a pair of rollers 23, and a recording medium (transfer paper) conveyed on the secondary transfer belt 24 and an intermediate transfer member 50. Can contact each other. A fixing device 25 is disposed in the vicinity of the secondary transfer device 22. The fixing device 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, a sheet reversing device 28 for reversing the transfer paper is disposed in the vicinity of the secondary transfer device 22 and the fixing device 25 in order to form an image on both sides of the transfer paper. .

Next, formation of a full-color image (color copy) using the tandem developing device 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 document is set on the contact glass 32 of the scanner 300. 400 is closed.
When a start switch (not shown) is pressed, when the document is set on the automatic document feeder 400, the document is transported and moved onto the contact glass 32, and then the document is set on the contact glass 32. Immediately after that, the scanner 300 is driven, and 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 received by the reading sensor 36 through the imaging lens 35 to be color. An original (color image) is read and used as black, yellow, magenta, and cyan image information.

Each image information of black, yellow, magenta, and cyan is stored in each image forming unit 18 (black image forming unit, yellow image forming unit, magenta image forming unit, and cyan image) in the tandem developing device 120. Each of the image forming units forms black, yellow, magenta, and cyan toner images with the two-component developer of the present invention. 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 device 120 is photosensitive as shown in FIG. Based on the color body 10 (the black photoconductor 10K, the yellow photoconductor 10Y, the magenta photoconductor 10M, and the cyan photoconductor 10C), the charging device 160 that uniformly charges the photoconductor 10, and each color image information. And exposing the photosensitive member to a color image-corresponding image (reference numeral L in FIG. 4), and forming an electrostatic latent image corresponding to each color image on the photosensitive member. Development is performed using the two-component developer of the present invention including color toners (black toner, yellow toner, magenta toner, and cyan toner) to form a toner image with each color toner. A developing device 61, a transfer charger 62 for transferring the toner image onto the intermediate transfer member 50, a cleaning device 63, and a charge eliminator 64 are provided, and each single color is based on the image information of each color. Images (black image, yellow image, magenta image, and cyan image) can be formed.
The black image, yellow image, magenta image, and cyan image formed in this way are formed on the black photoconductor 10K, respectively, on the intermediate transfer member 50 that is rotated by the support rollers 14, 15, and 16 shown in FIG. The transferred black image, the yellow image formed on the yellow photoconductor 10Y, the magenta image formed on the magenta photoconductor 10M, and the cyan image formed on the cyan photoconductor 10C are sequentially transferred (primary transfer). ) Then, a black image, a yellow image, a magenta image, and a 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 to feed out a sheet (recording paper) from one of the paper feed cassettes 144 provided in multiple stages in the paper bank 143. The sheets are separated one by one and sent to the paper feed path 146, transported by the transport roller 147, guided to the paper feed path 148 in the copying apparatus main body 110, and abutted against the registration roller 49 to stop. Alternatively, the sheet feeding roller 142 is rotated to feed out sheets (recording paper) on the manual feed tray 51, separated one by one by the separation roller 145, put into the manual feed path 146, and abutted against the registration roller 49 and stopped. . 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 synchronization with the synthesized color image (color transfer image) synthesized on the intermediate transfer member 50, and a sheet (recording paper) is interposed between the intermediate transfer member 50 and the secondary transfer device 22. , And the secondary transfer device 22 transfers the composite color image (color transfer image) onto the sheet (recording paper) (secondary transfer), whereby the color image is transferred and formed on the sheet (recording paper). The The residual toner on the intermediate transfer member 50 after 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 conveyed by the secondary transfer device 22 and sent to the fixing device 25, where the fixing color image (color transfer image) is generated by heat and pressure. ) 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. Alternatively, the sheet (recording paper) is switched by the switching claw 55 and reversed by the sheet reversing device 28 and returned to the transfer position. After the image is recorded on the back side, it is discharged by the discharge roller 56 and stacked on the discharge tray 57.

  EXAMPLES Next, although an Example and a comparative example are given and this invention is demonstrated further more concretely, this invention is not limited to these. Parts are based on weight.

[Manufacture of carrier core]
[Core Material Production Example 1]
MnCO ₃ , Mg (OH) ₂ , Fe ₂ O ₃ , and SrCO ₃ powder were weighed and mixed to obtain a mixed powder. This mixed powder was calcined at 900 ° C. for 1 hour in an air atmosphere in a heating furnace, and the obtained calcined product was cooled and pulverized to obtain a powder having a particle size of 3 μm or less. This powder was made into a slurry by adding 1 wt% of a dispersant together with water, and the slurry was supplied to a spray dryer and granulated to obtain a granulated product having an average particle size of about 40 μm.
This granulated product was loaded into a firing furnace and fired at 1200 ° C. for 4 hours in a nitrogen atmosphere. The obtained fired product was pulverized with a pulverizer, and the particle size was adjusted by sieving to obtain spherical ferrite particles 1 having a volume average particle size of about 35 μm, SF-1 of 136, and SF-2 of 131. Moreover, the volume resistivity of the spherical ferrite particles 1 was not measurable below the lower limit of measurement (breakdown).

[Core material production example 2]
The spherical ferrite particles 1 obtained in the core material production example 1 are subjected to surface oxidation treatment in a rotary electric furnace under atmospheric conditions so that the volume resistivity (LogΩ · cm) is 6.0. Thus, spherical ferrite particles 2 were obtained.

[Core Material Production Example 3]
The spherical ferrite particles 1 obtained in the core material production example 1 are subjected to surface oxidation treatment in a rotary electric furnace under atmospheric conditions so that the volume resistivity (LogΩ · cm) is 6.5. Thus, spherical ferrite particles 3 were obtained.

[Core Material Production Example 4]
The spherical ferrite particles 1 obtained in the core material production example 1 are subjected to surface oxidation treatment in a rotary electric furnace under atmospheric conditions so that the volume resistivity (LogΩ · cm) is 7.0. Thus, spherical ferrite particles 4 were obtained.

[Core Material Production Example 5]
The mixed powder was calcined in the same manner as in Core Material Production Example 1, and the obtained calcined product was cooled and pulverized to obtain a powder having a particle size of 3 μm or less.
This powder was made into a slurry by adding 1 wt% of a dispersant together with water, and the slurry was supplied to a spray dryer and granulated to obtain a granulated product having an average particle size of about 40 μm.
This granulated product was loaded into a firing furnace and fired at 1140 ° C. for 4 hours in a nitrogen atmosphere.
The obtained fired product was pulverized with a pulverizer, and the particle size was adjusted by sieving to obtain spherical ferrite particles having a volume average particle size of about 35 μm, SF-1 of 142, and SF-2 of 152.
The spherical ferrite particles 6 were subjected to a surface oxidation treatment in a rotary electric furnace under atmospheric conditions so that the volume resistivity (Log Ω · cm) was 6.5, and spherical ferrite particles 6 were obtained.

[Core Material Production Example 6]
The mixed powder was calcined in the same manner as in Core Material Production Example 1, and the obtained calcined product was cooled and pulverized to obtain a powder having a particle size of 3 μm or less.
This powder was made into a slurry by adding 1 wt% of a dispersant together with water, and the slurry was supplied to a spray dryer and granulated to obtain a granulated product having an average particle size of about 40 μm.
This granulated product was loaded into a firing furnace and fired at 1200 ° C. for 5 hours in a nitrogen atmosphere.
The obtained fired product was pulverized with a pulverizer, and the particle size was adjusted by sieving to obtain spherical ferrite particles having a volume average particle size of about 35 μm, SF-1 of 130, and SF-2 of 140.
The spherical ferrite particles 6 were subjected to a surface oxidation treatment in a rotary electric furnace under atmospheric conditions so that the volume resistivity (Log Ω · cm) was 6.5, and spherical ferrite particles 6 were obtained.

[Core Material Production Example 7]
The mixed powder was calcined in the same manner as in Core Material Production Example 1, and the obtained calcined product was cooled and pulverized to obtain a powder having a particle size of 1 μm or less.
This powder was made into a slurry by adding 1 wt% of a dispersant together with water, and the slurry was supplied to a spray dryer and granulated to obtain a granulated product having an average particle size of about 40 μm.
This granulated product was loaded into a firing furnace and fired at 1300 ° C. for 5 hours in a nitrogen atmosphere.
The obtained fired product was pulverized with a pulverizer, and the particle size was adjusted by sieving to obtain spherical ferrite particles having a volume average particle size of about 35 μm, SF-1 of 125, and SF-2 of 119. The spherical ferrite particles were subjected to surface oxidation treatment in a rotary electric furnace under atmospheric conditions so that the volume resistivity (Log Ω · cm) was 6.5, and spherical ferrite particles 7 were obtained.

[Resin synthesis example 1]
300 g of toluene was charged into a flask equipped with a stirrer, and the temperature was raised to 90 ° C. under a nitrogen gas stream. Subsequently, 3-methacryloxypropyltris (trimethylsiloxy) silane (sila) represented by CH ₂ ═CMe—COO—C ₃ H ₆ —Si (OSiMe ₃ ) ₃ (wherein Me is a methyl group) is added thereto. Plain TM-0701T manufactured by Chisso Corporation) 84.4 g (200 mmol), 3-methacryloxypropylmethyldiethoxysilane 39 g (150 mmol), methyl methacrylate 65.0 g (650 mmol) and 2,2′-azobis-2 -A mixture of 0.58 g (3 mmol) of methylbutyronitrile was added dropwise over 1 hour.
After completion of the addition, a solution of 2,2′-azobis-2-methylbutyronitrile (0.06 g, 0.3 mmol) dissolved in 15 g of toluene (2,2′-azobis-2-methylbutyronitrile A total amount of 0.64 g = 3.3 mmol) was added, and radical copolymerization was carried out by mixing at 90 to 100 ° C. for 3 hours to obtain a methacrylic copolymer.
The weight average molecular weight of the obtained methacrylic copolymer was 33,000. Subsequently, the methacrylic copolymer solution was diluted with toluene so that the nonvolatile content was 25% by mass to obtain a copolymer solution 1. The viscosity of the copolymer solution thus obtained was 8.8 mm ² / s, and the specific gravity was 0.91.

[Resin synthesis example 2]
500 g of toluene was put into a flask equipped with a stirrer, and the temperature was raised to 90 ° C. under a nitrogen gas stream. Subsequently, 3-methacryloxypropyltris (trimethylsiloxy) silane (sila) represented by CH ₂ ═CMe—COO—C ₃ H ₆ —Si (OSiMe ₃ ) ₃ (wherein Me is a methyl group) is added thereto. (Plain TM-0701T manufactured by Chisso Corporation) 126.6 g (300 mmol), 3-methacryloxypropyltrimethoxysilane 173.6 g (700 mmol) and 2,2′-azobis-2-methylbutyronitrile 0.58 g (3 Mmol) of the mixture was added dropwise over 1 hour.
After completion of the addition, a solution of 2,2′-azobis-2-methylbutyronitrile (0.06 g, 0.3 mmol) dissolved in 15 g of toluene (2,2′-azobis-2-methylbutyronitrile A total amount of 0.64 g = 3.3 mmol) was added, and radical copolymerization was carried out by mixing at 90 to 100 ° C. for 3 hours to obtain a methacrylic copolymer.
The weight average molecular weight of the obtained methacrylic copolymer was 35,000. Subsequently, it diluted with toluene so that the non volatile matter of this methacrylic copolymer solution might be 25 mass%, and the copolymer solution 3 was obtained. The viscosity of the copolymer solution thus obtained was 8.5 mm ² / s, and the specific gravity was 0.91.

[ Reference Example 1]
[Carrier coating layer]
Copolymer solution 1 [solid content 25% by weight] 37.6 parts by weight Silicone resin solution 930.5 parts by weight [solid content 20% by weight (SR2410: manufactured by Toray Dow Corning Silicone)]
9.1 parts by weight of aminosilane [solid content 100% by weight (SH6020: manufactured by Toray Dow Corning Silicone)]
EC-700 (Titanium Kogyo Co., Ltd., particle size: 0.35 μm) 426.7 parts by weight Toluene 2400 parts by weight The above raw material mixture for forming a carrier coating layer is dispersed with a paint shaker for 1 hour together with 1000 parts of 0.5 mm Zr beads. After that, the beads were removed with a mesh to obtain a resin coating film forming solution. Using the above-mentioned spherical ferrite particles 2: 5000 parts by weight as a core material, a solution obtained by adding 22.6 parts by weight of TC-750 (manufactured by Matsumoto Fine Chemical Co., Ltd.) to the above-mentioned coating film forming solution is added to the surface of the core material with a Spira coater (Okada Applied to the coater at a temperature of 70 ° C. and dried. The obtained carrier was baked in an electric furnace at 230 ° C. for 1 hour. After cooling, the ferrite powder bulk was pulverized using a sieve having an aperture of 63 μm, and the amount of binder resin was 4.5 parts by weight, the volume average particle size was 35.8 μm, and the volume resistivity (LogΩ · cm) was 11.4 [carrier. 1] was obtained.

[Toner 1]
(Toner binder synthesis)
724 parts of bisphenol A ethylene oxide 2-mole adduct, 276 parts of isophthalic acid and 2 parts of dibutyltin oxide were placed in a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen introduction tube, and reacted at 230 ° C. for 8 hours at normal pressure. The reaction was further carried out at a reduced pressure of 10 to 15 mmHg for 5 hours, followed by cooling to 160 ° C., and 32 parts of phthalic anhydride was added thereto and reacted for 2 hours.
Subsequently, it cooled to 80 degreeC and reacted with 188 parts of isophorone diisocyanate in ethyl acetate for 2 hours, and the isocyanate containing prepolymer (1) was obtained.
Next, 267 parts of the prepolymer (1) and 14 parts of isophoronediamine were reacted at 50 ° C. for 2 hours to obtain a urea-modified polyester (1) having a weight average molecular weight of 64,000.

In the same manner as above, 724 parts of bisphenol A ethylene oxide 2-mole adduct and 276 parts of terephthalic acid were polycondensed under normal pressure at 230 ° C. for 8 hours, and then reacted for 5 hours at a reduced pressure of 10 to 15 mmHg to give a peak molecular weight of 5000 An unmodified polyester (a) was obtained.
200 parts of urea-modified polyester (1) and 800 parts of unmodified polyester (a) are dissolved and mixed in 2000 parts of a mixed solvent of ethyl acetate / MEK (1/1), and an ethyl acetate / MEK solution of toner binder (1) is mixed. Got. Part of the mixture was dried under reduced pressure to isolate toner binder (1). Tg was 62 ° C.

(Create toner)
In a beaker, 240 parts of an ethyl acetate / MEK solution of the toner binder (1), 20 parts of pentaerythritol tetrabehenate (melting point: 81 ° C., melt viscosity: 25 cps), C.I. I. 4 parts of raw pigment of Pigment Yellow 154 was added and stirred at 12000 rpm with a TK homomixer at 60 ° C. to uniformly dissolve and disperse. In a beaker, 706 parts of ion-exchanged water, 294 parts of hydroxyapatite 10% suspension (Superite 10 manufactured by Nippon Chemical Industry Co., Ltd.) and 0.2 part of sodium dodecylbenzenesulfonate were uniformly dissolved. Next, the temperature was raised to 60 ° C., and the toner material solution was added and stirred for 10 minutes while stirring at 12000 rpm with a TK homomixer.
Subsequently, this mixed liquid was transferred to a Kolben equipped with a stirring bar and a thermometer, and the temperature was raised to 98 ° C. to remove the solvent. After the dispersion slurry was filtered under reduced pressure, a filter cake was obtained.

(Washing / drying / fluorine treatment)
1: 100 parts of ion-exchanged water was added to the filter cake, mixed with a TK homomixer (rotation speed: 12,000 rpm for 10 minutes), and then filtered.
2: 1OO parts of 10% sodium hydroxide aqueous solution was added to the filter cake of 1 above, mixed with a TK homomixer (30 minutes at 12,000 rpm), and then filtered under reduced pressure.
3: 100 parts of 10% hydrochloric acid was added to the filter cake of 2 above, mixed with a TK homomixer (10 minutes at 12,000 rpm), and then filtered.
4: 300 parts of ion-exchanged water was added to the filter cake of 3 above, mixed with a TK homomixer (rotation speed: 12,000 rpm for 10 minutes), and then filtered twice to obtain a cake.
This is designated as [Filter cake 1].
The above [Filter cake 1] was dried at 45 ° C. for 48 hours in a circulating dryer.
Thereafter, 15 parts of [Filter cake 1] are added to 90 parts of water, and 0.0005 part of the fluorine compound is dispersed therein, thereby attaching the fluorine compound (2) to the toner particle surface, and then circulating. It dried for 48 hours at 45 degreeC with the air dryer. Thereafter, the mixture was sieved with a 75 μm mesh to obtain toner base particles.
This is designated as [toner base particle 1]. To 100 parts of [Toner Base Particle 1] obtained above, 1.5 parts of hydrophobic silica and 0.7 parts of hydrophobized titanium oxide as external additives were added to a Henschel mixer at 2000 rpm × 30 seconds, 5 The toner was obtained by mixing in cycles. This is referred to as [Toner 1].
The developer obtained by mixing and stirring 7 parts of [Toner 1] and 93 parts of [Carrier 1] thus obtained was evaluated.

[ Reference Example 2]
[Carrier coating layer]
-Copolymer solution 1 [solid content 25% by weight] 32.9 parts by weight-Silicone resin solution 814.2 parts by weight [solid content 20% by weight (SR2410: manufactured by Toray Dow Corning Silicone)]
Aminosilane 7.9 parts by weight [solid content 100% by weight (SH6020: manufactured by Toray Dow Corning Silicone)]
EC-700 (Titanium Industry Co., Ltd., particle size: 0.35 μm) 373.3 parts by weight Toluene 2100 parts by weight The above coating raw material mixture is dispersed with a paint shaker for 1 hour together with 1000 parts of 0.5 mm Zr beads, and then meshed. The beads were removed to obtain a resin-coated film forming solution. Using 5000 parts by weight of the above-described spherical ferrite particles 2 as the core material, a solution obtained by adding 19.8 parts by weight of TC-750 (manufactured by Matsumoto Fine Chemical Co., Ltd.) to the above coating film forming solution is added to the surface of the core material with a Spira coater (Okada Applied to the coater at a temperature of 70 ° C. and dried. The obtained carrier was baked in an electric furnace at 230 ° C. for 1 hour. After cooling, the ferrite powder bulk was crushed using a sieve having a mesh size of 63 μm, and the amount of binder resin was 4.0 parts by weight, the volume average particle size was 35.6 μm, and the volume resistivity (LogΩ · cm) was 10.6. 2] was obtained.
The developer obtained by mixing and stirring 7 parts of [Toner 1] and 93 parts of [Carrier 2] thus obtained was evaluated.

[Example 3]
In Reference Example 1, the amount of the binder resin is 4.5 parts by weight, the volume average particle size is 36.0 μm, as in Reference Example 1, except that the spherical ferrite particles 3 are used instead of the spherical ferrite particles 2 as the core material. [Carrier 3] having a volume resistivity (Log Ω · cm) of 11.6 was obtained.
The developer obtained by mixing and stirring 93 parts of [Carrier 3] and 7 parts of [Toner 1] thus obtained was evaluated.

[Example 4]
In Reference Example 2, the amount of the binder resin was 4.0 parts by weight, the volume average particle size was 35.8 μm, in the same manner as in Reference Example 2 except that the spherical ferrite particles 4 were used instead of the spherical ferrite particles 2 as the core material. [Carrier 4] having a volume resistivity (Log Ω · cm) of 11.9 was obtained.

[Example 5]
[Carrier coating layer]
Copolymer solution 1 [solid content 25% by weight] 23.5 parts by weight Silicone resin solution 581.6 parts by weight [solid content 20% by weight (SR2410: manufactured by Toray Dow Corning Silicone)]
Aminosilane 5.7 parts by weight [solid content 100% by weight (SH6020: Toray Dow Corning Silicone)]
EC-700 (Titanium Industry Co., Ltd., particle size: 0.35 μm) 266.7 parts by weight Toluene 1500 parts by weight The above coating raw material mixture was dispersed with a paint shaker for 1 hour together with 1000 parts of 0.5 mm Zr beads, and then meshed. Then, the beads were removed to obtain a resin-coated film forming solution. Using 5000 parts by weight of the spherical ferrite particles 5 described above as a core material, a solution obtained by adding 14.1 parts by weight of TC-750 (manufactured by Matsumoto Fine Chemical Co., Ltd.) to the above coating film forming solution is added to the surface of the core material with a Spira coater (Okada Applied to the coater at a temperature of 70 ° C. and dried. The obtained carrier was baked in an electric furnace at 230 ° C. for 1 hour. After cooling, the ferrite powder bulk was pulverized using a sieve having an aperture of 63 μm, and the amount of binder resin was 2.8 parts by weight, the volume average particle size was 35.6 μm, and the volume resistivity (LogΩ · cm) was 10.4. 5] was obtained.
The developer obtained by mixing and stirring 7 parts of [Toner 1] and 93 parts of [Carrier 5] thus obtained was evaluated.

[Example 6]
In Example 5, the amount of the binder resin was 2.8 parts by weight, the volume average particle size was 35.8 μm, except that the spherical ferrite particles 6 were used instead of the spherical ferrite particles 5 in the same manner as in Example 5. [Carrier 6] having a volume resistivity (Log Ω · cm) of 11.1 was obtained.
The developer obtained by mixing and stirring 93 parts of [Carrier 6] and 7 parts of [Toner 1] thus obtained was evaluated.

[Example 7]
In Example 6, the amount of the binder resin was 2.8 parts by weight and the volume average particle size was 35.7 μm, except that the copolymer solution 2 was used instead of the copolymer solution 1 in Example 6. Thus, [Carrier 7] having a volume resistivity (Log Ω · cm) of 11.3 was obtained.
The developer obtained by mixing and stirring 93 parts of [Carrier 7] and 7 parts of [Toner 1] thus obtained was evaluated.

[Example 8]
[Carrier coating layer]
Silicone resin solution 855.3 parts by weight [solid content 20% by weight (SR2410: manufactured by Toray Dow Corning Silicone)]
Aminosilane 7.9 parts by weight [solid content 100% by weight (SH6020: manufactured by Toray Dow Corning Silicone)]
EC-700 (Titanium Industry Co., Ltd., particle size: 0.35 μm) 373.3 parts by weight Toluene 2100 parts by weight The above coating raw material mixture was dispersed with a paint shaker for 1 hour together with 1000 parts of 0.5 mm Zr beads, and then meshed. Then, the beads were removed to obtain a resin-coated film forming solution. Using 5000 parts by weight of the above-described spherical ferrite particles 1 as the core material, a solution obtained by adding 19.8 parts by weight of TC-750 (manufactured by Matsumoto Fine Chemical Co., Ltd.) to the above coating film forming solution is added to the surface of the core material with a Spira coater (Okada Applied to the coater at a temperature of 70 ° C. and dried. The obtained carrier was baked in an electric furnace at 230 ° C. for 1 hour. After cooling, the ferrite powder bulk was crushed using a sieve having a mesh size of 63 μm, and the amount of binder resin was 4.0 parts by weight, the volume average particle size was 35.9 μm, and the volume resistivity (LogΩ · cm) was 11.2 [Carrier 8] was obtained.
The developer obtained by mixing and stirring 93 parts of [Carrier 8] and 7 parts of [Toner 1] thus obtained was evaluated.

[Comparative Example 1]
Reference Example 2, except for using spherical ferrite particles 1 instead of spherical ferrite particles 2 as core material in the same manner as in Reference Example 2, the binder resin of 4.0 parts by weight, a volume average particle diameter 35.9Myuemu, [Carrier 9] having a volume resistivity (Log Ω · cm) of 10.8 was obtained.
The developer obtained by mixing and stirring 93 parts of [Carrier 9] and 7 parts of [Toner 1] thus obtained was evaluated.

[Comparative Example 2]
In Example 3, the amount of the binder resin is 4.5 parts by weight, the volume average particle size is 36.1 μm, except that the spherical ferrite particles 7 are used instead of the spherical ferrite particles 3 as the core material. [Carrier 10] having a volume resistivity (Log Ω · cm) of 11.3 was obtained.
The developer obtained by mixing and stirring 93 parts of [Carrier 10] thus obtained and 7 parts of [Toner 1] was evaluated.
That is, the following developer property evaluation was performed using the developer thus obtained. Table 1 shows the carrier properties, and Table 2 shows the developer property evaluation results.

[Developer characteristics evaluation]
<Print evaluation>
Each developer and replenishment toner created above are set in a commercially available digital full-color printer (RICOH Pro C901 manufactured by Ricoh Co., Ltd.), and a character chart (size of one character; approximately 2 mm × 2 mm) with an image area of 8% is 100 kp sheets After output, another 200 kp sheets were printed.

<Ghost image evaluation method>
For the ghost, after outputting 100 kp sheets, the longitudinal band chart shown in FIG. 6 is printed, and the density difference between the sleeve one round (a) and one round after (b) is determined by X-Rite 938 (manufactured by X-Rite). The average density difference between the three measurements at the center, rear, and front was taken as ΔID, and the ranking was divided below.
◎: Very good ○: Good △: Acceptable ×: Unusable level for practical use ◎, ○, △ were accepted and x was rejected.
A: 0.01 ≧ ΔID
○: 0.01 <ΔID ≦ 0.03
Δ: 0.03 <ΔID ≦ 0.06
×: 0.06 <△ ID

<Carrier adhesion evaluation>
Regarding carrier adhesion, after outputting 100 kp sheets, the development conditions are
Charging potential (Vd): -600V
Potential after exposure of the portion corresponding to the image portion: −100V
Development bias: DC-500V
Then, a solid image (30 mm × 30 mm) was output, and the number of white spots due to carrier adhesion on the image was counted.
◎: Very good ○: Good △: Acceptable ×: Unusable level for practical use ◎, ○, △ were accepted and x was rejected.
◎: 0 pieces ○: 1-2 pieces △: 3-4 pieces ×: 5 pieces or more

<Resistance value change>
The static resistance of the carrier was measured using a 0 kp printed developer and a 300 kp printed developer.
At this time, the developer of FIG. 7 is used as the developer, the carrier (3) and the toner (5) are separated by using a blow-off cage (7) having a 795 mesh net, and the toner (5) is removed by suction. Then, the resistance value of the carrier was measured using the apparatus of FIG. 2, and ΔLogR with 0 kp was calculated, and the following determination was made.
◎: Very good ○: Good △: Acceptable ×: Unusable level for practical use ◎, ○, △ were accepted and x was rejected.
A: ΔLogR ≦ 0.5
○: 0.5 <ΔLogR ≦ 1
△: 1 <△ LogR ≦ 2
×: 2 <ΔLogR

<Amount of spent toner>
The toner component is extracted with methyl ethyl ketone for the carrier running 300 kp sheets and the initial carrier, and the difference is expressed as the amount of spent toner (expressed in wt% with respect to the carrier weight).
◎: Very good ○: Good △: Acceptable ×: Unusable level for practical use ◎, ○, △ were accepted and x was rejected.
A: 0 or more and less than 0.03 Wt% B: 0.03 Wt% or more and less than 0.07 Wt% Δ: 0.07 Wt% or more and less than 0.15 Wt% ×: 0.15 Wt% or more

  Although the embodiments of the present invention have been specifically described above, the present invention is not limited to these embodiments, and these embodiments of the present invention depart from the spirit and scope of the present invention. And can be changed or modified.

(About Fig. 1 and Fig. 7)
3 Carrier 5 Toner 7 Blow-off cage 11 Cell made of fluororesin container 12a Electrode 12b Electrode 13 Carrier (FIGS. 3 and 4)
DESCRIPTION OF SYMBOLS 10 Photoconductor 10K Black photoconductor 10Y Yellow photoconductor 10M Magenta photoconductor 10C Cyan photoconductor 14 Support roller 15 Support roller 16 Support roller 17 Intermediate transfer body cleaning device 18 Image forming means 21 Exposure device 22 Secondary transfer device 23 Roller 24 Secondary transfer belt 25 Fixing device 26 Fixing belt 27 Pressure roller 28 Sheet reversing device 32 Contact glass 33 First traveling body 34 Second traveling body 35 Imaging lens 36 Reading sensor 49 Registration roller 50 Intermediate transfer body 51 Manual feed Tray 53 Manual feed path 55 Switching claw 56 Ejection roller 57 Ejection tray 58 Roller 61 Developing device 62 Transfer charger 63 Cleaning device 64 Static eliminator 100 Image forming device 110 Copying device main body 120 Tandem type developing device 130 Document table 42 the paper feed roller 143 paper bank 144 sheet cassette 145 separating roller 146 feed path 147 transport rollers 148 feed path 160 charging device 200 feeder table 300 Scanner 400 automatic document feeder (ADF)
L exposure

Japanese Patent No. 3356948 JP 2005-157002 A JP 11-231652 A JP-A-7-72733 JP 7-128983 A JP-A-7-92913 Japanese Patent Laid-Open No. 11-65247

Claims (14)

In an electrostatic latent image developing carrier having a coating layer containing at least a binder resin and fine particles on a carrier core material,
The carrier core material is surface-oxidized;
The volume resistivity (Log Ω · cm) of the carrier core material is 6.0 or more and 7.0 or less,
A carrier for developing an electrostatic latent image, wherein the core surface exposed area ratio of the carrier is 0.1 to 5.0%. 2. The electrostatic latent image developing carrier according to claim 1, wherein SF-2 of the electrostatic latent image developing carrier is in a range of 115 to 150. The coating layer includes a resin component;
The electrostatic latent image developing carrier according to claim 1, wherein the resin component contains at least a silicon resin . The coating layer includes a resin component;
The resin component contains a resin obtained by heat-treating a copolymer containing at least the A component represented by the following general formula (A) and the B component represented by the following general formula (B). The carrier for developing an electrostatic latent image according to any one of claims 1 to 2, wherein the carrier for developing an electrostatic latent image is provided .
(In the formula, R ¹ represents a hydrogen atom or a methyl group, R ² represents an alkyl group having 1 to 4 carbon atoms, R ³ represents an alkyl group having 1 to 8 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, m Represents an integer of 1 to 8. A plurality of R ² may be the same or different, X represents 10 to 90 mol%, and Y represents 90 to 10 mol%.) The carrier for electrostatic latent image development according to claim 4, wherein the copolymer includes a copolymer represented by the following general formula (1).
(Wherein R ¹ Is a hydrogen atom or a methyl group, R ² Represents an alkyl group having 1 to 4 carbon atoms, R ³ Represents an alkyl group having 1 to 8 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, and m represents an integer of 1 to 8. Multiple R ¹ And R ² May be the same or different. X represents 10 to 40 mol%, Y represents 10 to 40 mol%, Z represents 30 to 80 mol%, and 60 mol% <Y + Z <90 mol%. ) 6. The electrostatic latent image developing carrier according to claim 1, wherein the fine particles are conductive fine particles . The electrostatic latent image developing carrier according to any one of claims 1 to 6, wherein the conductive fine particles have a volume average particle diameter of 50 to 800 nm . An electrostatic latent image developing developer comprising the electrostatic latent image developing carrier according to any one of claims 1 to 7 and a toner . The developer for developing an electrostatic latent image according to claim 8, wherein the toner is a color toner . A developer-containing container comprising the developer for developing an electrostatic latent image according to claim 8 . 10. The process for forming an electrostatic latent image on the electrostatic latent image carrier, and the electrostatic latent image developing development according to claim 8 or 9, wherein the electrostatic latent image formed on the electrostatic latent image carrier is formed. Forming a toner image using the agent, transferring the toner image formed on the electrostatic latent image carrier to a recording medium, and fixing the toner image transferred to the recording medium. An image forming method comprising: An electrostatic latent image carrier that forms an electrostatic latent image; and a developing unit that develops the formed electrostatic latent image into a toner image using the developer for developing an electrostatic latent image according to claim 8 or 9. An image forming apparatus comprising: transfer means for transferring the toner image to a recording medium; and fixing means for fixing the toner image transferred to the recording medium . An electrostatic latent image carrier, and means for developing the electrostatic latent image formed on the electrostatic latent image carrier using the electrostatic latent image developing developer according to claim 8 or 9 are integrated at least integrally. A process cartridge which is supported . The replenishment developer comprising the electrostatic latent image developing carrier and the toner according to claim 1, wherein a blending ratio of the electrostatic latent image developing carrier and the toner is the electrostatic latent image. A replenishing developer, wherein the toner is 2 to 50 parts by mass with respect to 1 part by mass of the developing carrier .