JP2003280290A - Carrier for electrophotography, developer for electrophotography and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a carrier for electrophotography of two component developer having high durability, further having high durability even in the combination with a toner containing a releasing agent, developer for electrophotography, image forming method and image forming device. <P>SOLUTION: In this carrier for electrophotography with a coated film comprising at least binder resin and particle, particle diameter (D) and thickness (h) of binder resin film has a relation; 1<[D/h]<10, and the particle and/or coated film is surface-treated with one kind or more selected from titanate coupling agent, fluorine-containing silane coupling agent and aceto-alkoxy aluminum diisopropylate. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an electrophotographic carrier for developing an electrostatic latent image in electrophotography, electrostatic recording, electrostatic printing, etc., an electrophotographic developer, an image forming method, and an electrophotographic developer. The present invention relates to a container to be stored and an image forming apparatus.

[0002]

2. Description of the Related Art Generally, in an image forming method such as an electrophotographic method or an electrophotographic method, a toner and an electrophotographic carrier (hereinafter, referred to as a carrier) for developing an electrostatic latent image formed on a latent image carrier. The developer obtained by stirring and mixing with (hereinafter simply referred to as “carrier”) is used. This developer is
It is required to be a properly charged mixture. Generally, as a method for developing an electrostatic latent image, a method using a two-component developer obtained by mixing a toner and a carrier and a method using a one-component developer containing no carrier are known. . The former developing method using a two-component developer has a drawback in that although a relatively stable and good image can be obtained, carrier deterioration and variation in the mixing ratio of toner and carrier are likely to occur. On the other hand, the latter one-component developer does not have the drawbacks of the former, but has the disadvantage that the chargeability is difficult to stabilize.

Further, when the electrostatic latent image is repeatedly developed using a two-component developer, the toner in the developer is consumed and the toner density fluctuates, so that a stable image is obtained during printing. In addition, it is necessary to replenish the toner as necessary to suppress this fluctuation. Generally, as a method for controlling the toner supply amount, a copying machine is equipped with a transparency detection sensor, a fluidity detection sensor, an image density detection sensor, a bulk density detection sensor, etc. Is the mainstream these days. The sensor is a system that controls a toner replenishment amount by developing a certain image pattern on a latent image carrier and detecting an image density from reflected light.

The granular carrier used in such a two-component developing system prevents the filming of the toner on the surface of the carrier, the formation of a uniform surface of the carrier, the prevention of surface oxidation, the prevention of deterioration of moisture sensitivity and the life of the developer. For the purpose of extension, protection from scratches or abrasion by the carrier of the photoconductor, control of charge polarity or adjustment of charge amount, a hard and high-strength coating layer is usually provided by coating with a suitable resin material. It is carried out, for example, in Japanese Patent Laid-Open No. 58-108548.
In the publications, etc., those coated with a specific resin material,
For example, JP-A-54-155048 and JP-A-5757.
-40267, JP-A-58-108549, JP-A-59-166968, JP-B-1-19
No. 584, Japanese Patent Publication No. 3-628, and Japanese Patent Laid-Open No. 6-2
No. 02381 or the like in which various additives are added to the coating layer of the carrier, and in JP-A-5-273789 or the like, one in which the additive is attached to the carrier surface is used, and further in JP-A-9- Japanese Patent No. 160304 discloses a device in which conductive particles larger than the coating film thickness are contained in the coating film. Further, JP-A-8-6307 discloses that a benzoguanamine-n-butyl alcohol-formaldehyde copolymer is used as a main component in a carrier coating material, and is disclosed in Patent No. 26.
Japanese Patent No. 83624 discloses the use of a crosslinked product of a melamine resin and an acrylic resin as a carrier coating material.

However, the durability is still insufficient, and there are problems such as spent on the carrier surface of the toner, destabilization of the charge amount, and resistance reduction due to abrasion of the coating resin. However, the image quality of the copied image deteriorates as the number of copies increases, and therefore improvement is required. Therefore, JP-A-2
Japanese Patent Laid-Open No. 001-188388 discloses that the relationship between the particle diameter and the binder resin film thickness is defined, and the specific resistance of the particles is defined. As a result, the effect is remarkable as compared with the conventional ones, but the demand for the durability of the developer in recent years has further increased, and further improvement is desired. On the other hand, in image forming apparatuses such as copying machines, there is a demand for further downsizing, and for this reason, downsizing of photoconductors and developing devices is being studied. Among them, the fixing device is also required to be downsized. Current fixing devices apply silicone oil or the like to prevent offset between the fixing roller and recording paper. Therefore, an oil tank and an oil applying device are required, and it is difficult to downsize the fixing device.
In order to solve this, it has been considered to add a release agent to the toner to prevent offset. However, the toner containing the release agent has a problem that the release agent is easily attached to the surface of the carrier and the durability as a developer is short, and it has high durability even in combination with the toner containing the release agent. Carriers have great demands.

[0006]

Therefore, the present invention has been made in view of the above problems and demands, and an object thereof is to provide an electrophotographic carrier of a two-component developer having high durability. Is. A second object is to provide an electrophotographic carrier of a two-component developer having high durability even in combination with a toner containing a release agent. Furthermore, it is to provide an electrophotographic developer using these highly durable electrophotographic carriers. Also, an image forming method using these highly durable electrophotographic developers,
An image forming apparatus is provided.

[0007]

In order to solve the above-mentioned problems, the invention according to claim 1 provides a carrier having a coat film composed of at least a binder resin and particles, wherein the particle diameter (D) and the binder resin are The film thickness (h) is 1 <[D / h] <1
In the relationship of 0, the particles are titanate coupling agents,
A carrier for electrophotography, which is selected from among fluorine-containing silane coupling agents and acetoalkoxyaluminum diisopropylate, or which is surface-treated with two or more kinds. According to a second aspect of the present invention, in a carrier having a coat film composed of at least a binder resin and particles, the particle diameter (D) and the binder resin film thickness (h) are 1 <[D
/ H] <10, and the coating film is a carrier for electrophotography containing one or more selected from titanate coupling agents, fluorine-containing silane coupling agents, and acetoalkoxyaluminum diisopropylate. . According to a third aspect of the present invention, in a carrier having a coat film composed of at least a binder resin and particles, the particle diameter (D) and the binder resin film thickness (h) are 1 <
In the relationship of [D / h] <10, the particles are surface-treated with one or more selected from titanate coupling agents, fluorine-containing silane coupling agents, and acetoalkoxyaluminum diisopropylate,
The coat film is an electrophotographic carrier containing one or more selected from titanate coupling agents, fluorine-containing silane coupling agents, and acetoalkoxyaluminum diisopropylate. In the invention according to claim 4, the specific resistance of the particles is 10 ¹² Ω · cm.
The above is the electrophotographic carrier according to any one of claims 1 to 3. The invention according to claim 5 provides the electrophotographic carrier according to any one of claims 1 to 4, wherein the particles are alumina and / or silica. The invention according to claim 6 is
The content of the particles is 40 to 95 w of the coating film composition component.
It is t%. The electrophotographic carrier according to claim 1. The invention according to claim 7 is such that the film thickness of the binder resin is 0.05 μm to 1.00 μm.
The electrophotographic carrier according to item 6. The invention according to claim 8 is the electrophotographic carrier according to any one of claims 1 to 7, wherein the binder resin contains at least a resin obtained by crosslinking reaction of an acrylic resin and an amino resin or / and a silicone resin. The invention according to claim 9 is the electrophotographic carrier according to any one of claims 1 to 8, wherein the Tg of the resin is 20 to 100 ° C.

According to a tenth aspect of the invention, the electrophotographic developer comprises an electrophotographic developer comprising at least a toner containing a binder resin and a pigment, and the electrophotographic carrier according to any one of claims 1 to 9. Use as an agent. The invention according to claim 11 is the electrophotographic developer according to claim 10, wherein the toner contains a release agent. The invention according to claim 12 is an image forming method for visualizing an electrostatic latent image,
Use the electrophotographic developer according to claim 10.
Image forming method. A thirteenth aspect of the present invention is a multicolor image forming method for visualizing an electrostatic latent image to form a multicolor image, wherein a multicolor image is formed using the electrophotographic developer according to the tenth to eleventh aspects. Let's say Claim 14
The invention described in claim 1 is a container for accommodating a developer for electrophotography used in an image forming apparatus, wherein the container is
The container for housing the electrophotographic developer according to Item 11. According to a fifteenth aspect of the present invention, in the image forming apparatus for visualizing an electrostatic latent image, the image forming apparatus includes the container filled with the electrophotographic developer according to the fourteenth aspect.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below. As a result of continuing studies to solve the above-mentioned problems of the prior art, the present inventors have found that in a carrier having at least a coating film containing a binder resin and particles, the particle diameter (D) and the binder resin film thickness. (H) is 1 <[D
/ H] <10, and the particles are surface-treated with a titanate coupling agent, a fluorine-containing silane coupling agent, and acetoalkoxyaluminum diisopropylate alone or in combination of two or more, and the improvement effect is remarkable. I understood. This is because the particles have larger irregularities than the coat film, so by stirring for frictionally charging the developer, friction with the toner or friction between the carriers causes
It is possible to reduce the contact with the binder resin which is accompanied by a strong impact. As a result, it is possible to prevent the spent of the toner on the carrier, and it is also possible to prevent the film of the binder resin, which is the charging generation site, from being scraped.

However, since the convex portion, that is, the surface of the particle relaxes the contact with the binder resin accompanied by a strong impact, the particle itself is always in a state of being easily detached from the coating film. In order to cope with higher durability, it is necessary to suppress the detachment of the particles. According to the present inventor, the particles are treated with a titanate coupling agent, a fluorine-containing silane coupling agent, an acetoalkoxyaluminum diisopropionate. It was possible to suppress the detachment of particles by surface-treating them with one or more than one rate. This is because the adhesion between the particles and the binder resin in the coat film was increased, and the detachment of the particles was suppressed. In the case of a toner containing a release agent, the release agent plays a central role in accelerating the detachment of the particles, but the release agent is increased due to the increased adhesiveness between the particles and the binder resin in the coating film. The effect is comparable to that of the toner containing no toner.

Further, the present inventors have revealed that there is a specific range for [D / h]. [D /
When h] is less than 1, the particles are buried in the binder resin, and the effect is significantly reduced, which is not preferable. Traditionally,
When [D / h] is 5 or more, the contact area between the particles and the binder resin is small, so that a sufficient restraining force cannot be obtained and the particles are easily detached, which is not preferable. When a ring agent, a fluorine-containing silane coupling agent, or acetoalkoxyaluminum diisopropylate is surface-treated alone or in combination of two or more, the adhesiveness with the binder resin is increased, and when it is 5 or more or less than 10 However, it became possible to obtain a coat film in which particles were not detached. The surface treatment method used in the present invention may be any conventionally known method as long as the particles can be surface-treated with the treatment agent.
There is a method of diluting with a suitable solvent so as to have a concentration of about 1 to 10%, mixing and stirring the particles therein and thoroughly stirring, and then removing the solvent and drying. Further, a catalyst for accelerating the reaction may be added to the treatment liquid.

The titanate coupling agent, the fluorine-containing silane coupling agent, and the acetoalkoxyaluminum diisopropylate are not only surface-treated on the particles but also have the same effect when they are contained in the coating film alone or in combination of two or more kinds. I got it. In addition, the effect was more prominent when the particles were surface-treated and the particles were contained in the coat film. Further, it is desirable that these amounts are 0.01 to 20 parts by weight with respect to 100 parts by weight of the particles. More preferably 0.05 to 10 parts by weight is desirable

As titanate coupling agents, isopropyl triisostearoyl titanate, isopropyl tris (dioctyl pyrophosphate) titanate, isopropyl tri (N-aminoethyl-aminoethyl) titanate, tetraoctyl bis (ditridecyl phosphite) titanate, tetra (2,2-Diallyloxymethyl-1-butyl) bis (ditridecyl) phosphite titanate, bis (dioctylpyrophosphate) oxyacetate titanate, bis (dioctylpyrophosphate) ethylene titanate, isopropyl trioctanoyl titanate, isopropyl dimethacryl isoate Stearoyl titanate, isopropyl tridodecyl benzene sulfonyl titanate, isopropyl isostearoyl diac Ruchitaneto, isopropyl tri (dioctyl phosphate) titanate, isopropyl tricumylphenyl titanate, tetraisopropyl bis (dioctyl phosphite) titanate, can be exemplified.

Further, a fluorine-containing silane coupling agent
And then C_FourF₉CH_TwoCH_TwoSi (OCH_Three)_Three, C
₈F₁₇CH_TwoCH_TwoSi (OCH_Three)_Three, C₇F₁₅
COOCH_TwoCH_TwoCH_TwoSi (OCH_Three)_Three, C₇F
₁₅COSCH_TwoCH_TwoCH_TwoSi (OCH_Three)_Three, C
₇F₁₅CONHCH_TwoCH_TwoCH_TwoSi (OC
_TwoH₅)_Three, C₇F₁₅CONHCH_TwoCH_TwoCH_TwoS
i (OCH_Three)_Three, C₈F₁₇SO_TwoNHCH_TwoCH_Two
CH_TwoSi (OC_TwoH₅)_Three, C₈F₁₇CH_TwoCH_Two
SCH_TwoCH_TwoSi (OCH_Three)_Three, C₁₀F₂₁CH
_TwoCH_TwoSCH_TwoCH_TwoSi (OCH_Three)_Three, C₈F
₁₇CH_TwoCH_TwoSiCH_Three(OCH_Three)_Two, C₈F
₁₇SO_TwoN (CH_TwoCH_TwoCH_Three) CH_TwoCH_TwoCH
_TwoSi (OCH_Three)_Three, C₈F₁₇SO_TwoNHCH_TwoC
H_TwoN (SO_TwoC₈F₁₇) CH_TwoCH_TwoCH_TwoSi
(OCH_Three)_Three Can be illustrated.

Examples of acetoalkoxyaluminum diisopropylate include acetomethoxyaluminum diisopropylate, acetoethoxyaluminum diisopropylate, and acetopropoxyaluminum diisopropylate.

Further, in order to suppress the decrease in the charge amount when the developer is stored for a long period of time, the specific resistance of the particles is 10 ¹² Ω.
・ It is effective to be cm or more. This is because even if the particles have a contact with the core material and are exposed on the surface, leakage of charges is suppressed, so that stable chargeability can be obtained.
On the other hand, if the specific resistance of the particles is less than 10 ¹² Ω · cm, the leakage of charges cannot be suppressed, and stable charging properties cannot be obtained, which is not preferable. Also, as mentioned in the above-mentioned prior art,
A technique similar to the present invention in which conductive particles larger than the coating resin film thickness are contained in the coating film (JP-A-9-
160304), the particles of the present invention are not used as a resistance adjusting material as in the prior art, but are used as a protective material for a coating film resin and a surface shape adjusting material. . Furthermore, a titanium coupling agent, a fluorine-containing silane coupling agent, and acetoalkoxyaluminum diisopropylate are indispensable for suppressing the desorption of the particles.

Further, the particles are alumina and the content thereof is in the range of 40 to 95 wt% of the coating film composition component, preferably 7
The effect is remarkable when the content is 0 to 90 wt%.
Further, the particles are silica and the content is in the range of 40 to 95 wt% of the coating film composition component, preferably 70 to 90 wt%.
Therefore, the effect is remarkable. Further, alumina and silica may be mixed and used. When the content of the particles is less than 40 wt%, the ratio of the particles is smaller than the ratio of the binder resin on the surface of the carrier particles, so that the effect of alleviating the contact with the binder resin with a strong impact is reduced. Is not preferable because sufficient durability cannot be obtained. On the other hand, when it exceeds 95 wt%, the proportion of particles is too large as compared with the proportion of the binder resin on the carrier surface, so that the proportion of the binder resin at the charging generation point becomes insufficient, which is sufficient. The charging ability cannot be exhibited. In addition, since the amount of the particles is too large compared to the amount of the binder resin, the ability of the binder resin to hold the particles becomes insufficient and the particles are easily detached, which is not preferable because sufficient durability cannot be obtained. Further, the content range of particles is different from the technique similar to the present invention disclosed in Japanese Patent Laid-Open No. 9-160304 mentioned above. The technique disclosed in Japanese Patent Application Laid-Open No. 9-160304 discloses "0.01-50 w of coating resin.
t% ”, which is converted to the content calculation method of the present invention,
It is "0.01 to 33.33 wt% of the coating film composition component". In this case, the durability is improved as compared with the conventional case, but as described above, the proportion of the particles is smaller than the proportion of the binder resin on the surface of the carrier particles, so that a strong impact on the binder resin is obtained. The effect of alleviating the accompanying contact is small and sufficient durability cannot be obtained, which is not preferable.

According to the present invention, it is important that the binder resin contains a resin obtained by crosslinking an acrylic resin and an amino resin and / or a silicone resin. As this amino resin, a conventionally known amino resin can be used, but the use of guanamine or melamine significantly improves the charge amount imparting ability. Also, as the silicone resin, a conventionally known silicone resin can be used. In addition to the resins listed here,
A resin generally used as a coating resin for a carrier can be used, and of course, it may be used in combination with the above resin. For example, polystyrene resin, poly (meth) acrylic resin, polyolefin resin, polyamide resin, polycarbonate resin, polyether resin, polysulfinic acid resin, polyester resin, epoxy resin, polybutyral resin, urea Various thermoplastic resins such as resin, urethane / urea resin, and fluorine resin, thermosetting resins and mixtures thereof, and copolymers of these resins, but not limited to these.

The Tg of these resins is 20-100.
C., preferably 25 to 80.degree. C. is used. When the Tg of the resin is within this range, the resin has an appropriate elasticity, and due to the friction between the toner and the carrier or the friction between the carriers during the stirring for triboelectrifying the developer, the resin to the binder resin is At the time of contact with a strong impact, the impact can be absorbed and the coat film can be maintained without being damaged. If Tg is less than 20 ° C,
Since the binder resin blocks even at room temperature, it has poor storage stability and cannot be practically used, which is not preferable. on the other hand,
When Tg exceeds 100 ° C., the binder resin becomes too hard and brittle so that the impact cannot be absorbed, the binder resin is scraped from the brittleness, and the particles cannot be retained, resulting in desorption. It is not preferable because it can be easily released.

As the core material of the carrier, in order to prevent the carrier from adhering to the electrostatic latent image carrier and scattering of the carrier, a carrier having an average particle diameter of at least 20 μm is used, and carrier streaks or the like are generated. From the viewpoint of preventing deterioration of image quality such as prevention, a film having a size of at most 100 μm is used. As a specific material, a material known to be used for a carrier for a two-component developer for electrophotography, for example, ferrite, magnetite, iron, nickel or the like may be appropriately selected and used according to its use and purpose of use.

Carbon black or an acid catalyst may be used alone or in combination as the charge and resistance modifier. As the carbon black, any of those generally used for carriers or toners can be used. As the acidic catalyst, one having a catalytic action can be used. For example, those having a reactive group such as a fully alkylated type, a methylol group type, an imino group type, and a methylol / imino group type, are not limited to these.
The carrier is used as a two-component developer composed of toner, but the composed toner may be black toner or multicolor toner used in the multicolor image forming method.

The image forming apparatus of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of an image forming apparatus equipped with a container filled with a developer using the electrophotographic carrier of the present invention. Here, a developing section (1) mounted in the main body of the image forming apparatus and a developer storage container (2) filled with a developer using the electrophotographic carrier of the present invention to be replenished to the developing section (1). ) And a developer flow means (3) for connecting the two, respectively. The developing section (1) includes a developing housing (4) containing a two-component developer (D) in which toner and a carrier are mixed, and first and second stirring screws (5) for stirring and mixing the developer (D). , (6) and a developing roller (7), and the developing roller (7) is arranged to face the photoconductor (8) of the latent image carrier. Photoreceptor (8)
Is rotationally driven in the direction indicated by the arrow, and an electrostatic latent image is formed on the surface thereof. Reference numeral (26) in the figure denotes a connecting member (2
4) A cap fitted on or above the filter (25). Around the photoconductor (8), a charging means, an exposing means, a transferring means, a discharging means, which are not shown,
Other known units such as cleaning means are arranged. By rotating the first and second stirring screws (5) and (6), the developer (D) in the developing housing (4) is agitated, and the toner and the carrier are triboelectrically charged with opposite polarities. . The developing roller (7) in which the developer (D) is rotationally driven in the arrow direction
Is supplied to the peripheral surface of the developing roller (7), and the supplied developer is carried on the peripheral surface of the developing roller (7) and is conveyed in the rotation direction by the rotation of the developing roller (7). Next, the amount of the transported developer is regulated by the doctor blade (9), and the regulated developer is carried to the developing area between the photoconductor (8) and the developing roller (7), where The toner in the developer electrostatically transfers to the electrostatic latent image on the surface of the photoconductor, and the electrostatic latent image is visualized as a toner image.

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto. An example of toner production will be described below. <Toner Production Example 1: Black Toner 1> Water: 1200
Part, phthalocyanine green hydrous cake (solid content 30
%): 200 parts, carbon black (trade name MA60:
(Mitsubishi Chemical Co., Ltd.): 540 parts are thoroughly stirred with a flasher. Epoxy resin (Mn: 3500) 1200
Part, and kneading at 150 ° C for 30 minutes, then xylene 1000
After adding parts, the mixture was kneaded for an additional 1 hour, water and xylene were removed, the mixture was rolled and cooled, and pulverized with a pulverizer to obtain a masterbatch pigment. Next, epoxy resin (Mn: 3500): 100
Parts, the above masterbatch: 5 parts, and a zinc salicylate derivative (trade name: Bontron E84: Orient Chemical Co., Ltd.): 4 parts were mixed with a mixer, melt-kneaded with a two-roll mill, and the kneaded product was rolled and cooled. Then, pulverization and classification were performed to obtain a toner having a weight average particle diameter of 7.8 μm. Further, an external additive such as silica was added to impart fluidity and mixed with a Henschel mixer to obtain Black Toner 1. <Toner Production Example 2: Black Toner 2> Toner Production Example 1
All were produced in the same manner as in Production Example 1 except that 5 parts of carnauba wax was added to the above.

The production examples of the surface-treated particles are shown below.
You <Production Example of surface-treated particles 1: Alumina particles 1> Isopropyi
Lutriisostearoyl titanate (brand name KR TT
S: Ajinomoto Co.) 5 parts by weight, hexane 495 parts by weight
Alumina (average particle size 0.3 μm, resistivity:
10¹⁴Ω · cm) Add 50 parts by weight of particles and stir for 2 hours,
Then, after filtering and removing the solvent, the mixture was dried at 120 ° C. for 2 hours.
It was dried and surface-treated with a titanate coupling agent.
Lumina particles 1 were obtained. <Production Example 2 of surface-treated particles: Alumina particles 2> Silane cup
Pulling agent C₇F₁₅CO_TwoCH_TwoCH_TwoCH_TwoSi
(OCH_Three) _Three(Manufactured by Mitsubishi Metals) 5 parts by weight, hexane 4
Alumina (average particle size 0.3μ
m, specific resistance 10¹⁴Ω · cm) Add 50 parts by weight of particles to 2
After stirring for a time and subsequent filtration to remove the solvent, 120
Fluorine-containing silane coupling agent after drying at ℃ for 2 hours
Alumina particles 2 surface-treated with a coating agent were obtained. <Production Example 3 of surface-treated particles: Alumina particles 3> Acetoeth
Xyaluminum diisopropylate (trade name AL-
M: manufactured by Ajinomoto Co.) 5 parts by weight, 495 parts by weight of hexane
Alumina (average particle size 0.3 μm, specific resistance 1
0¹⁴Ω · cm) Add 50 parts by weight of particles and stir for 2 hours.
Filtered to remove the solvent, and then dried at 120 ° C for 2 hours.
Go and surface treat with acetoalkoxydiisopropylate
Alumina particles 3 were obtained.

An example of manufacturing the carrier is shown below. <Carrier Production Example 1: Carrier 1> Acrylic resin solution (solid content 50% by weight): 56.0 parts, guanamine solution (solid content 77% by weight): 15.6 parts, alumina particles 1:
160.0 parts, toluene: 900 parts, and butyl cellosolve: 900 parts were dispersed by a homomixer for 10 minutes to prepare a coating film forming solution. As the core material, calcined ferrite powder (trade name F-300: average particle size 50 μm: manufactured by Powder Tech Co., Ltd.) was used, and the coating film forming solution was applied to the surface of the core material to a film thickness of 0.
Spira coater (made by Okada Seiko Co., Ltd.) to be 15 μm
And then dried. The obtained carrier was left standing in an electric furnace at 300 ° C. for 2 hours for firing. After cooling, the ferrite powder bulk was crushed using a sieve having openings of 100 μm to obtain Carrier 1. In the binder resin film thickness measurement, the coating film covering the carrier surface can be observed by observing the carrier cross section with a transmission electron microscope. Therefore, the average value of the film thickness was taken as the film thickness.

<Carrier Production Example 2: Carrier 2> All were produced in the same manner as Carrier Production Example 1 except that the alumina particles 1 of Carrier Production Example 1 were changed to alumina particles 2. <Carrier Production Example 3: Carrier 3> All were produced in the same manner as Carrier Production Example 1 except that the alumina particles 1 of Carrier Production Example 1 were changed to alumina particles 3.

<Carrier Production Example 4: Carrier 4> Acrylic resin solution (solid content 50% by weight): 56.0 parts, guanamine solution (solid content 77% by weight): 15.6 parts, alumina particles (average particle size 0 0.3 μm, specific resistance 10 ¹⁴ Ω · c
m): 160.0 parts, isopropylpyrutris (dioctyl pyrophosphate) titanate (trade name KR 3
8S: manufactured by Ajinomoto Co., Inc.): 1.0 part by weight, toluene: 900
Parts, butyl cellosolve: all were manufactured in the same manner as in Charari Production Example 1 except that the formulation was changed to 900 parts. <Carrier Preparation Example 5: Carrier 5> isopropyl pills tris (dioctyl pyrophosphate) of the carrier preparation 4 titanate (trade name KR 38S: Ajinomoto Co., Ltd.) Silane coupling agent _{C 8 F 17 CH 2 CH 2} SiCH
₃ (OCH ₃ ) ₂ (manufactured by Mitsubishi Metals Co., Ltd.) was used and manufactured in the same manner as in Carrier Manufacturing Example 4. <Carrier Production Example 6: Carrier 6> Isopropyl pyrtris (dioctyl pyrophosphate) titanate (trade name KR 38S: manufactured by Ajinomoto Co.) of Carrier Production Example 4 was converted to acetoethoxy aluminum diisopropylate (trade name AL-M: manufactured by Ajinomoto Co., Inc.). All were produced in the same manner as in Carrier Production Example 4, except that the carrier was changed to (). <Carrier Production Example 7: Carrier 7> All were produced in the same manner as Carrier Production Example 4 except that the alumina particles in Carrier Production Example 4 were changed to Alumina particles 1. <Carrier Production Example 8: Carrier 8> Acrylic resin solution (solid content 50% by weight): 56.0 parts, guanamine solution (solid content 77% by weight): 15.6 parts, alumina particles (average particle size 0.3 μm, Specific resistance 10 ¹⁴ Ω · cm) 16
0.0 parts, toluene: 900 parts, butyl cellosolve: 9
All were manufactured in the same manner as in Carrier Manufacturing Example 1 except that the formulation was changed to 00 parts.

Example 1 The carrier 1 thus obtained and the black toner 1 were put in a ball mill and mixed for 10 minutes so that the toner concentration was 5% to obtain a developer. The developer and the black toner 1 were set in a commercially available digital full-color copying machine (imagioColor2800 manufactured by Ricoh Co., Ltd.), and running evaluation of 600,000 sheets was performed. Tables 1 and 2 show the results of obtaining the charge reduction amount and the resistance reduction amount of the carrier after the running. The amount of charge reduction referred to here is a charge amount measuring device using a general blow-off method (Toshiba Chemical (KK) ): TB-200), the amount of charge (Q1) measured on the carrier was obtained by removing the toner in the developer after running by the blow-off device, and the amount of charge measured by the same method as described above. It means the amount obtained by subtracting (Q2), and the target value is 7.0 (μc / g) or less. Further, the cause of the decrease in the charge amount is toner spent on the surface of the carrier. Therefore, by reducing the toner spent, the decrease in charge amount can be suppressed. The amount of resistance decrease is the resistance of the initial carrier measured parallel electrodes: gap 2
mm electrodes and apply DC200V for 30se
The carrier in which the toner in the developer after running was removed by the blow-off device from the value (R1) obtained by converting the resistance value after c was measured by a high resist meter into the volume resistivity (R1) was measured by the resistance measurement. Value measured by the same method (R
It is the amount obtained by subtracting 2), and the target value is 2.0 (L
og (Ω · cm)) or less. Further, since the cause of the resistance decrease is the abrasion of the binder resin film of the carrier, it is possible to suppress the amount of resistance reduction by reducing the abrasion of the film.

Example 2 Black Toner 1 of Example 1
All were evaluated in the same manner as in Example 1 except that black toner 2 was used. The evaluation results are shown in Tables 1 and 2. <Example 3> The same evaluation as in Example 2 was carried out except that the carrier 1 in Example 2 was changed to the carrier 2. The evaluation results are shown in Tables 1 and 2. <Example 4> Evaluation was made in the same manner as in Example 2 except that the carrier 1 of Example 2 was changed to the carrier 3. The evaluation results are shown in Tables 1 and 2. <Example 5> Evaluation was made in the same manner as in Example 2 except that the carrier 1 of Example 2 was changed to the carrier 4. The evaluation results are shown in Tables 1 and 2. <Example 6> Evaluation was made in the same manner as in Example 2 except that the carrier 1 of Example 2 was changed to the carrier 5. The evaluation results are shown in Tables 1 and 2. <Example 7> The same evaluation as in Example 2 was carried out except that the carrier 1 of Example 2 was changed to the carrier 6. The evaluation results are shown in Tables 1 and 2. <Example 8> The same evaluation as in Example 2 was carried out except that the carrier 1 of Example 2 was changed to the carrier 7. The evaluation results are shown in Tables 1 and 2.

Comparative Example 1 Evaluations were made in the same manner as in Example 1 except that the carrier 1 of Example 1 was changed to the carrier 8. The evaluation results are shown in Tables 1 and 2. Comparative Example 2 The same evaluation as in Example 1 was carried out except that the carrier 2 in Example 2 was changed to the carrier 8.

The evaluation results are shown in Tables 1 and 2.

<Table 1><Table 1: Combination of Examples 1 to 8 and Comparative Examples 1 and 2>

[0032]

[Table 2] <Table 2: Results of running 60,000 sheets> From Table 1 and Table 2, by using the carrier of the present invention,
The effect was more than double that of conventional durability. Also,
When combined with a toner containing a release agent, the effect was 6 times or more that of the conventional result.

[0033]

As will be apparent from the detailed and specific description above, according to the present invention, a more durable electrophotographic carrier, an electrophotographic developer, an image forming method, a storage container and an image forming apparatus can be provided. It becomes possible to provide. Further, it is possible to provide a highly durable electrophotographic carrier, electrophotographic developer, image forming method, storage container, and image forming apparatus even in combination with a toner containing a release agent.

[Brief description of drawings]

FIG. 1 is a diagram showing a container filled with the electrophotographic developer of the present invention and an image forming apparatus equipped with the container.

[Explanation of symbols]

1 development department 2 developer storage container 3 developer feeding means 4 Development housing 5 stirring screw 6 stirring screw 7 developing roller 8 photoconductor 9 doctor blade 24 Connection member 25 filters 26 caps D Electrophotographic developer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 15/08 503 G03G 9/10 351 507 361 362 352 15/08 507L (72) Inventor Masahide Yamashita Tokyo Ota-ku Nakamagome 1-3-6 Incorporated Ricoh Co., Ltd. (72) Inventor Kosuke Suzuki Kouma Ota-ku Nakamagome 1-3-6 Incorporated Ricoh Co., Ltd. (72) Inventor Satomi Tamura Nakamagome Ota-ku, Tokyo 1-3-6 Ricoh Co., Ltd. (72) Inventor Takayuki Koike 1-3-6 Nakamagome, Ota-ku, Tokyo F-Term (R) 2/3 Ricoh Co., Ltd. (Reference) 2H005 AA06 AA21 BA06 BA07 BA15 CA01 CA02 CA12 CA14 CA17 CA25 CA26 CA28 CB07 CB13 DA10 EA01 EA03 EA05 EA07 EA10 FA02 2H077 AA11 BA10 DB14 EA03 EA24 GA14 2H300 EJ42 EJ47 EJ50 EJ52 EJ59 GG37

Claims (15)

[Claims] 1. A carrier having a coat film comprising at least a binder resin and particles, wherein the particle diameter (D) and the binder resin film thickness (h) are 1 <[D / h].
In the relationship of <10, the particles are surface-treated with one or more selected from titanate coupling agents, fluorine-containing silane coupling agents, and acetoalkoxyaluminum diisopropylate. Electrophotographic carrier. 2. A carrier having a coat film comprising at least a binder resin and particles, wherein the particle diameter (D) and the binder resin film thickness (h) are 1 <[D / h].
In the relationship of <10, the electrophotographic carrier is characterized in that the coating film contains one or more selected from titanate coupling agents, fluorine-containing silane coupling agents, and acetoalkoxyaluminum diisopropylate. . 3. A carrier having a coat film comprising at least a binder resin and particles, wherein the particle diameter (D) and the binder resin film thickness (h) are 1 <[D / h].
In the relationship of <10, the particles are surface-treated with one or more selected from titanate coupling agents, fluorine-containing silane coupling agents and acetoalkoxyaluminum diisopropylate, and the coating film is a titanate cup. A carrier for electrophotography, which is selected from ring agents, fluorine-containing silane coupling agents, and acetoalkoxyaluminum diisopropylate, or contains at least two kinds. 4. The specific resistance of the particles is 10 ¹² Ω · cm.
The electrophotographic carrier according to any one of claims 1 to 3, wherein the electrophotographic carrier is as described above. 5. The carrier for electrophotography according to claim 1, wherein the particles are alumina and / or silica. 6. The content of the particles is 40 to 95 wt% of the coating film composition component.
5. The electrophotographic carrier according to item 5. 7. The film thickness of the binder resin is from 0.05 μm to
The carrier for electrophotography according to claim 1, which has a thickness of 1.00 μm. 8. The carrier for electrophotography according to claim 1, wherein the binder resin contains at least a resin obtained by crosslinking reaction of an acrylic resin and an amino resin or / and a silicone resin. 9. The carrier for electrophotography according to claim 1, wherein Tg of the resin is 20 to 100 ° C. 10. An electrophotographic developer comprising the toner comprising at least a binder resin and a pigment, and the electrophotographic carrier according to any one of claims 1 to 9. 11. The electrophotographic developer according to claim 10, wherein the toner contains a release agent. 12. An image forming method for visualizing an electrostatic latent image, wherein the electrophotographic developer according to claim 10 is used. 13. A multicolor image forming method for forming a multicolor image by visualizing an electrostatic latent image, wherein the electrophotographic developer according to claim 10 is used. Forming method. 14. A container for containing the electrophotographic developer used in an image forming apparatus, wherein the container contains the electrophotographic developer according to any one of claims 10 to 11. 15. An image forming apparatus for visualizing an electrostatic latent image, comprising the container filled with the electrophotographic developer according to claim 14.