JPH07104522A - Resin coated carrier for electrophotographic developer, its production and developer using the same - Google Patents

Abstract

PURPOSE:To produce a resin coated carrier excellent in environmental stability, having such satisfactory rising characteristics as to instantaneously impart electrostatic chargeability to a toner replenished at the time of printing and excellent also in durability and to provide a developer using the carrier. CONSTITUTION:A coating resin layer of silicone resin contg. an aminosilane coupling agent or modified silicone resin is formed on the core material of a carrier to obtain the objective resin coated carrier. The content of the aminosilane coupling agent in the coating resin is 6-25wt.% and the amino equiv. of the coupling agent is 163-235.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-coated carrier for an electrophotographic developer used in electrophotographic copying machines, printers and the like, a method for producing the same, and a developer using the carrier.

[0002]

2. Description of the Related Art A two-component developer used in electrophotography is composed of a toner and a carrier. The carrier is mixed and agitated with the toner in a developing box to give a desired charge to the toner and to give the charge. It is a carrier material that carries the borne toner to the electrostatic latent image on the photoreceptor to form a toner image.

The carrier remains on the magnet roll,
The toner is returned to the developing box again, mixed again with new toner, stirred again, and repeatedly used.

Therefore, as a carrier, during use,
It is required for the toner to constantly obtain desired charging characteristics under all environments.

However, the conventional developer has two problems due to collision of carriers with each other by stirring, friction between the developing box and carrier, and the like. One is that the toner is fused to the surface of the carrier and spent is formed. On the other hand, carrier resistance changes due to peeling and falling of the coating resin layer on the surface of the carrier, resulting in image deterioration (image density is insufficient, image fog defect, etc.) after printing as compared with the image at the initial stage. There is. Further, not only is the developer (carrier) deteriorated by stirring, but also due to environmental changes during printing durability, the charge amount decreases at high temperature and high humidity, and toner scattering and image fog defects occur.

On the other hand, at low temperature and low humidity, on the contrary, the charge amount rises, causing a problem of insufficient image density, and finally the life of the developer is shortened. Especially as a full-color carrier, compared with conventional copiers, printers, etc.
Since the solid portion is larger than the printed portion, the amount of toner transferred to the photosensitive member is large, and the durability of the carrier is further required.

[0007] A method of coating various resins has been proposed in order to stabilize charging due to such a spent state and environmental changes during printing durability, but a satisfactory method has not been obtained yet.

That is, it is said that a carrier coated with a silicone-based resin or a fluorine-based resin has a low critical surface tension and is unlikely to cause spent to be fused with the toner on the carrier surface, and has a long life as a developer. On the contrary, since the charging ability of the toner and the carrier is weak, the toner is often scattered, resulting in contamination inside the machine and eventually defects on the image, and the life is short in the comprehensive evaluation.

In addition, against the deterioration of the image due to the collision between the carriers due to stirring, the peeling of the coating resin layer on the carrier surface due to the friction between the developing box and the carrier, and the falling off (insufficient image density, defective fog on the image). It has been proposed that a silane coupling agent be used in order to improve the adhesiveness of the resin coating layer (Japanese Patent Laid-Open No. 60-19156).

However, although there is an improvement in the adhesiveness of the coating layer, there are problems that toner scattering and image fogging occur due to fluctuations in the charge amount under various environmental conditions.

On the other hand, a carrier in which a coating layer made of a silicone resin is provided on the surface of a carrier core material treated with a silane coupling agent in order to improve the adhesion between the carrier core material and the silicone resin is also described ( JP-A-62-12
1463).

However, since this product does not have a component of an aminosilane coupling agent having an effective amino group on the outermost surface of the carrier, it does not have sufficient charging ability for the negative polarity toner, and the toner scatters during printing durability. I couldn't get anything satisfactory.

In recent years, two resin layers containing an aminosilane coupling agent have been coated to change the resin components or additives of the intermediate layer and the outermost layer (Japanese Patent Laid-Open No. 5-72815). JP-A-5-13446
7 publication). Further, a carrier is described which is characterized in that a concentration gradient is applied to a silane coupling agent or the like in the thickness direction of the silicone resin layer (Japanese Patent Laid-Open No. Hei 5 (1999) -53977).
-204189 publication).

Since these constituents of these carriers are not uniform in the carrier resin layer, a change over time occurs particularly when the carrier is left on the silicone resin-coated carrier, and the curing of the outermost layer and the intermediate layer in the resin layer deviates. In the production, there is a large difference between the charging characteristics of the original toner and the charging characteristics of the toner after the passage of time, and in the case where a conductive substance is added, the charge amount decreases at high humidity, Furthermore, when the resin layers are peeled off or dropped during printing, the resistance of the carrier changes greatly and the final evaluation cannot be said to be durable.

On the other hand, in the resin-coated carrier using the conventional aminosilane coupling agent as described above, the aminosilane coupling agent accounts for 3% by weight of the coating resin.
Most of them are contained in an amount of less than or equal to about 5% by weight in the resin as described in JP-A-61-140951.

In recent years, there has been an increasing demand for uniform reproduction of images with many solid parts such as barcodes and images with graphic designs, etc., in place of slips with many printed parts such as printers, especially in the case of full color and the like. Since there are more solid areas, the amount of toner consumed and the amount of replenishment remarkably increase. In the electrophotographic development process, it is desired that the toner constantly maintains desired charging characteristics under all environmental conditions, but in recent years, high toner consumption and replenishment system development conditions are not satisfactory. Not obtained.

Therefore, conventional carriers and developers have been found to prevent spent and improve the adhesiveness of the carrier coating layer. By using an aminosilane coupling agent, the ability to impart a slight amount of charge to the toner can be obtained. However, there is no toner having a good rising charging characteristic especially under high temperature and high humidity conditions. The charge imparting ability to small particle size toner and high toner density for high resolution used in printers and full color machines with many solid parts in recent years is not sufficient, and the replenished toner is instantly charged during printing. The current situation is that the amount could not be increased, and finally, sufficient durability was not obtained.

[0018]

That is, the object of the present invention is to improve the environmental stability, and to give a charging characteristic to a toner which is newly replenished by repeating copying, in an instant, which has a rising characteristic. The purpose of the present invention is to provide a good carrier and a method for producing the same, and further to improve the performance of the electrophotographic developer.

Another object of the present invention is to provide a carrier suitable for improving the durability of a full-color developer which consumes a large amount of toner and is often in contact with a high-concentration toner, and a method for producing the same. Further, the life of the developer is extended, and the object is to reduce the copy cost per sheet.

A further object of the present invention is to provide a developer having a long storage period, which does not have a qualitative aging as a carrier or a developer by coating with a uniform layer.

[0021]

DISCLOSURE OF THE INVENTION The present inventors have earnestly studied to further improve the carrier described in the above-mentioned JP-A-60-19156, and as a result, have found that silicone-based silicone containing an aminosilane coupling agent is used. In a resin-coated carrier coated with a resin or a modified silicone resin, the content ratio of the aminosilane coupling agent in the coating resin and the amino equivalent in the aminosilane coupling agent are related to the charging ability of the toner especially at high temperature and high humidity. As a result of finding out that there is something, and further conducting research such as printing durability test, as a result, a resin coat that has good rising characteristics of charging in various environments and is durable depending on the structure of the aminosilane coupling agent and the baking conditions of the coating layer. We have found that a carrier can be obtained, and in particular, full-color printers that often come into contact with toner Surface of the carrier core material for aircraft, and found that the combination is effective with grain size, and have completed the present invention.

That is, according to the present invention, a carrier core material has a coating resin layer made of a silicone resin or a modified silicone resin containing an aminosilane coupling agent, and the aminosilane coupling agent is contained in the coating resin. The resin coated carrier for an electrophotographic developer is characterized in that the proportion is 6 to 25% by weight and the amino equivalent of the aminosilane coupling agent is 163 to 235.

The present invention will be described in detail below. The resin-coated carrier of the present invention has, on the carrier core material, a coating resin layer made of a silicone-based resin containing an aminosilane coupling agent or a modified silicone-based resin. The content ratio of the aminosilane coupling agent in this coating resin is
It is 6 to 25% by weight, preferably 12 to 22% by weight. Further, it is particularly preferably 14 to 18% by weight.
When the content ratio of the aminosilane coupling agent is less than 6% by weight, the content of amino groups is too small, and the charging ability with the toner under high humidity cannot be sufficiently obtained. On the other hand, if it exceeds 25% by weight, the absolute value of the charge amount will increase and the image density will decrease under low humidity. Further, if an aminosilane coupling agent is contained in the coating resin more than necessary, delamination of the resin or the like will occur, and durability will not be obtained.

The amino equivalent of this aminosilane coupling agent is 163 to 235, preferably 179 to 22.
It is 1. The amino equivalent referred to herein is the molecular weight of the aminosilane coupling agent divided by the number of nitrogen atoms held by the aminosilane coupling agent. When the amino equivalent is less than 163, in addition to the amino group at the end of the aminosilane coupling agent, it has a secondary or tertiary amino group contained in the main chain, and the secondary or tertiary amino group is It hardly contributes to the rising charging characteristics with the toner, and conversely causes fluctuations in the charging characteristics at high humidity, which is not preferable. On the other hand, when the amino equivalent exceeds 235, the number of amino groups having charge imparting ability is small, and good rising charging characteristics with the toner cannot be obtained. A general aminosilane coupling agent can be represented by the following general formula.

[0025]

[Chemical 2]

(Wherein R ₁ is an alkylene group having 1 to 4 carbon atoms, a phenylene group, R ₂ and R ₃ are alkyl groups having 1 to 2 carbon atoms, R ₄ and R ₅ are hydrogen atoms, methyl groups and ethyl groups. , Phenyl group, aminomethyl group, aminoethyl group, aminophenyl group, etc., where n = 2 or 3.)

However, the aminosilane coupling agent used in the present invention has the following formula.

[0028]

[Chemical 3]

(However, R ₁ is an alkylene group having 1 to 4 carbon atoms, R ₂ and R ₃ are alkyl groups having 1 to 2 carbon atoms, and n is 2 or 3.)

That is, in the present invention, the aminosilane coupling agent is a primary amine because R ₄ and R _{5 in} the above general formula are both hydrogen. On the other hand, a secondary or tertiary amine substituted with a methyl group, an ethyl group, a phenyl group or the like has weak polarity and has little effect on the charge rising property with the toner.

When R ₄ and R ₅ are an aminomethyl group, an aminoethyl group or an aminophenyl group as described above, the most advanced silane coupling agent is a primary amine. The amino group in the organic group of the chain does not contribute to the rising charging property with the toner, but is adversely affected by moisture when the humidity is high. , The charging ability is reduced during printing, and finally the life is shortened. An example is N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane.

R ₁ is an alkylene group having 1 to 4 carbon atoms, R ₂ ,
R ₃ is an alkyl group having 1 to 2 carbon atoms, among which R _{1 is}
Is most preferably an alkylene group having 3 carbon atoms, and R ₂ and R ₃ are most preferably a combination of alkyl groups having 2 carbon atoms. Further, R ₁ is an aliphatic alkylene group, rather than a phenylene group, because of its structure, it is suitable for a silicone resin, particularly a methylsilicone resin. Regarding R ₂ and R ₃ , it is necessary that R ₃ is at least n = 2, and most preferably n = 3. This is because it reacts with the base resin in the silicone-based resin or the modified silicone-based resin, and the aminosilane coupling agent adheres firmly.

The silicone resin may be any straight silicone resin having an organosiloxane bond, and commercially available products include KR-271 and KR manufactured by Shin-Etsu Chemical Co., Ltd.
-255, SR manufactured by Toray Dow Corning Silicone Co., Ltd.
-2410, SR-2406, SR-2411, TSR-127B and TSR-144 manufactured by Toshiba Silicone Co., Ltd., and a catalyst or the like may be added as necessary. Further, as the modified silicone resin, a modified silicone resin such as an alkyd resin, a polyester resin, an epoxy resin, a polyurethane resin, an acrylic resin can be used, and as a commercially available product, Shin-Etsu Chemical KR-206 (alkyd resin modified), KR-9706 (acrylic resin modified), ES-
1001N (epoxy resin modified), Toray Dow Corning Silicone SR-2101 (alkyd resin modified) and the like. A straight silicone resin is preferable, and a methyl silicone resin is particularly preferable in terms of film strength.

As the core material in the resin-coated carrier of the present invention, conventionally known materials can be used. For example,
Examples include ferromagnetic metals such as iron and cobalt, magnetite, hematite, and ferrite. It is preferable to use ferrite or iron whose surface is easy to control,
Ferrite is particularly preferable.

The surface properties of the carrier core material in the present invention are
The surface property index is preferably in the range of 1.0 to 2.1, and particularly preferably 1.5 to 2.0.

When the surface property index is less than 1.0, the surface property becomes too smooth or the particles of the carrier core material are sintered together, and a uniform shape cannot be maintained and a uniform resin coating becomes difficult. Further, the excess resin granulates the carriers with each other, so that good coating cannot be performed. On the other hand, if the surface property index exceeds 2.1, the surface property will not be smooth, the resin layer will penetrate into the inside of the carrier core material, and it will be difficult to coat the surface uniformly. Even if the amount of resin coating is increased by this, the thickness of the resin coating layer varies due to the unevenness of the outermost surface of the core material, the effective function of the aminosilane coupling agent cannot be obtained, and good durability cannot be obtained.

The surface property index mentioned here is represented by a value obtained by dividing the specific surface area by the BET method by the specific surface area by the air permeation method, and serves as a scale for evaluating the carrier surface property. BET
As for the specific surface area by the method, not only the convex and concave portions of the surface layer of the carrier core material but also the pores inside the carrier core material continuous from the surface can be measured by substituting N ₂ gas,
This is a good measurement method for calculating the amount of resin coating when performing resistance control in resin coating. Further, the specific surface area by the air permeation method is a method of measuring the specific surface area from the time required for air to pass through the carrier filled in the cell, and the value is relatively limited to the surface portion of the carrier core material. It is a measurement method suitable for measuring the area.

Therefore, the surface property index can be expressed by calculating the value of each specific surface area obtained by the both measurements by the following formula.

Surface property index = specific surface area (c
m ² / g) / specific surface area by air permeation method (cm ² / g)

For example, for measuring the specific surface area by the BET method, an apparatus similar to or similar to the Flowsorb II2300 manufactured by Shimadzu can be used. In addition, as a specific surface area measurement by the air permeation method, Shimadzu SS-2
Devices similar to or similar to 00 may be used.

The average particle size of the carrier core material in the present invention is preferably 20 to 100 μm, particularly 30 to 65 μm.
m is preferable. If the average particle size is less than 20 μm, the distribution of carrier particles will contain a large amount of fine particles, and the magnetization per particle will be low, resulting in carrier scattering. Further, if the average particle size of the carrier exceeds 100 μm, the specific surface area decreases, and the toner scatters. Further, in full color with many solid portions, the reproduction of solid portions is particularly poor, which is not preferable.

The solvent used for forming the coating resin layer in the present invention is toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cerusol butyl acetate or the like.

The resin coating amount in the resin coated carrier is 0.1 to 5.0% by weight based on the total amount of the resin coated carrier.
And preferably 0.15 to 2.0% by weight, and particularly preferably 0.8 to 1.5% by weight. If the coating amount of the resin is less than 0.1% by weight, a uniform coating may be formed on the carrier surface in the range of the surface property index (1.0 to 2.1) of the carrier core material used in the invention. If the amount exceeds 5.0% by weight, the coating layer becomes too thick and granulation of carrier particles occurs, and uniform carrier particles tend not to be obtained.

The method of forming the coating resin layer on the carrier core material is to dissolve the silicone resin or modified silicone resin containing the aminosilane coupling agent shown above in a solvent and then dip the carrier core material. After uniformly applying the same resin solution by spraying, brush coating, etc., the solvent is removed by drying, and then baking is performed.

The baking device may be either an external heating system or an internal heating system, for example, a fixed or fluid type electric furnace, a rotary electric furnace, a burner furnace, or a microwave baking. The baking temperature is preferably 180 to 300 ° C., especially 2
The optimum temperature is 20 to 280 ° C. Further, as a matter of course, when the baking temperature is less than 180 ° C., the silicone resin or the modified silicone resin containing the aminosilane coupling agent is not sufficiently cured, and a coating resin layer that is strong and does not fall off from the carrier core material is formed. I can't get it. Further, the reaction between the aminosilane coupling agent and the silicone base resin does not proceed sufficiently. On the other hand, if the temperature exceeds 300 ° C., a part of the silicone resin or a part of the aminosilane coupling agent may be decomposed, the surface layer of the resin may be roughened, and a uniform coating layer may not be obtained.

The carrier of the present invention is mixed with a toner and used as a two-component developer. As the toner used here, a colorant or the like is dispersed in a binder resin. The binder resin used for the toner is not particularly limited, but polystyrene, chloropolystyrene,
Examples thereof include a styrene-chlorostyrene copolymer, a styrene-acrylic acid ester copolymer, a styrene-methacrylic acid copolymer, a rosin-modified maleic acid resin, an epoxy resin, a polyester resin, and a polyurethane resin. These may be used alone or as a mixture.

Any appropriate charge control agent can be used as the charge control agent that can be used in the present invention. Examples thereof include metal salicylate chelate, metal-containing monoazo dye, and nigrosine base.

As the coloring body, conventionally known dyes and / or pigments can be used, and those used for full color can be used. For example, carbon black, phthalocyanine blue, permanent red, permanent yellow and the like can be used.
The content of this colorant is 100% by weight of the binder resin,
It may be about 0.5 to 10% by weight. In addition, external additives such as silica fine powder can be added according to the toner particles.

To prepare the toner according to the present invention, for example, the above-mentioned binder resin, charge control agent, and colorant are sufficiently mixed with a mixer such as a Henschel mixer, kneaded with a twin-screw extruder, and then cooled. After coarsely pulverizing the mixture with a feather mill, etc., use a jet pulverizer, a wind classifier, etc., and a particle size of 4 to 20 μm.
It can be obtained by forming particles having an average particle size of 7 μm, adding an external additive and the like, and mixing with a mixer.

[0050]

EXAMPLES The present invention will be specifically described below based on Examples and the like.

Example 1 As shown in Table 1, ferrite particles (trade name: F-
2035, manufactured by Powder Tech Co., Ltd., with an average particle size of 65
μm, surface property index 1.3 (BET specific surface area: 267c
m ² / g, air permeation method specific surface area: 205 cm ² / g) carrier silicone material (trade name: SR-
2411, solid content 20% by weight, Toray Dow Corning
8% by weight of γ-aminopropylmethyldimethoxysilane (amino equivalent: 163) was mixed with the solid content of Silicone Co., Ltd., dissolved in a toluene solvent, and 0.7 was added to the carrier core material using a fluidized bed. The coating was performed by weight% and baking was performed at 200 ° C. for 2 hours to obtain a carrier coated with the above resin.

The toner used for this carrier evaluation was a CF-70 magenta commercially available from Minolta Camera Co.
Various toners of cyan, yellow and black were used. By using this carrier and each color toner described above, a developer having a toner concentration of 8.0% by weight is prepared for each color, and CF-
Printing durability evaluation was performed using 70 (manufactured by Minolta Camera Co., Ltd.). Table 2 shows the image evaluation (image density, image fog, carrier adhesion, toner scattering, environmental change of charge amount, charge amount rising characteristic, comprehensive evaluation) at that time.

In Table 2, five ranks from ⊚ to × are used to rank the image evaluations. A level of Δ or more is a practically possible level. The specific evaluation method is as follows.

[Image Evaluation of Carrier]: Image Density (ID) A copy was made under appropriate exposure conditions, and the I.D. D. Was evaluated.
The image density of the solid area was measured by a Macbeth densitometer and ranked. ◎: The density of the original is reproduced very well without any uneven density. ○: The density of the original is reproduced without unevenness of the density. △: The image density is good (practical level). : Uneven image with uneven density or edge effect, image density is lower than original density x: Overall image density is low, and image density is much lower than original density

Fog on Image For fogging on an image, toner fogging on a white background image is evaluated using a colorimetric color difference meter Z-300 manufactured by Nippon Denshoku Industries Co., Ltd. or a device equivalent thereto, and ranked. It was ◎: Less than 0.5% ○: 0.5 to less than 1.0% △: 1.0 to less than 1.5% ▲: 1.5 to less than 2.5% ×: 2.5% or more

Carrier Adhesion The carrier adhesion on the image, that is, the level of white spots was evaluated and ranked. ◎: Not in 10 A3 sheets ○: 1 to 5 in 10 A3 sheets △: More than 5 in 10 A3 sheets, up to 3 in 3 A3 sheets ▲: In 3 A3 sheets More than 5 and less than 10 x: More than 10 out of 3 A3 sheets

Toner Scattering Unfavorable toner scattering conditions such as the degree of toner scattering that causes stains on the copy paper and the contamination of the charging charger were evaluated and ranked.

Change in charging environment Charge amount (Q _LL ) after storage of the developer in an environment of 10 ° C. and 15% for 24 hours and after storage for 24 hours in an environment of 30 ° C. and 85% (Q _HH ). Then, the difference ΔQ; ΔQ = Q _LL −Q _HH (μc / g) was calculated and ranked to evaluate the environmental change of charging. ◎: ΔQ = 3μc or less ○: ΔQ = 3μc or more and 5μc or less △: ΔQ = 5μc or more and 7μc or less ▲: ΔQ = 7μc or more and 12μc or less ×: ΔQ = 12μc or more Micron E-SPART A
It was determined by using NALYZER or an equivalent device.

Charge rising property The developer to which the new toner is replenished is stirred and mixed in the developing machine, the charge imparting speed to the replenishment toner is obtained from the variation value of the charge amount during the stirring time, and the charging is performed. Was evaluated. ◎: Very good level in charge rising property evaluation ○: No problem in charge rising property evaluation △: Practically usable level in charge rising property evaluation ▲: Problem in charge rising property evaluation , Unusable level ×: There is a problem and it cannot be practically used

Evaluation of each image in the printing durability test (image density, fog on the image,
Adhesion of carrier, toner scattering, environmental change of charging, rising property of charging) were comprehensively evaluated and ranked. ◎: Very good level in each image evaluation ○: No problem level in each image evaluation △: Practically usable level in each image evaluation ▲: There is a problem item in each image evaluation Unusable level x: There is a problem in most evaluations, and it is a level that cannot be practically used

Example 2 As shown in Table 1, ferrite particles (trade name: F-
400, manufactured by Powder Tech Co., Ltd., average particle diameter 26 μ
m, surface property index 2.1 (BET specific surface area: 1217c
m ² / g, air permeation method specific surface area: 580 cm ² / g) and a silicone resin (trade name: SR-
2411, solid content 20% by weight, Toray Dow Corning
25% γ-aminopropylmethyldimethoxysilane (amino equivalent: 163) based on the solid content of Silicone Co., Ltd.)
The carrier core material was mixed in an amount of 2.1% by weight in the same manner as in Example 1 and further baked at 280 ° C. for 3 hours to obtain a carrier coated with the above resin.

Using this carrier and each toner used in Example 1, a developer having a toner concentration of 8.0% by weight was prepared for each color, and CF-70 (manufactured by Minolta Camera) was used.
The printing durability was evaluated. Table 2 shows the image evaluation at that time.

Example 3 As shown in Table 1, ferrite particles (trade name: F-
300, manufactured by Powder Tech Co., Ltd., average particle size 44μ
m, surface index 1.7 (BET specific surface area: 546 cm
² / g, air permeation method specific surface area: 322 cm ² / g) and a silicone resin (trade name: SR-2) on the carrier core material.
411, solid content 20% by weight, 16% by weight of γ-aminopropyltriethoxysilane (amino equivalent: 221) based on the solid content of Toray Dow Corning Silicone Co., Ltd.
After mixing, the carrier core material was coated with 0.9% by weight in the same manner as in Example 1, and further baked at 250 ° C. for 3 hours to obtain a carrier coated with the above resin.

Using this carrier and each toner used in Example 1, a developer having a toner concentration of 8.0% by weight was prepared for each color, and CF-70 (manufactured by Minolta Camera) was used.
The printing durability was evaluated. Table 2 shows the image evaluation at that time.

Example 4 As shown in Table 1, ferrite particles (trade name: F-
350, manufactured by Powder Tech Co., Ltd., average particle diameter 38μ
m, surface property index 1.9 (BET method specific surface area: 705 cm
² / g, air permeation method specific surface area: 371 cm ² / g) and a silicone resin (trade name: SR-2)
411, solid content 20% by weight, 20% by weight of γ-aminopropyltriethoxysilane (amino equivalent: 221) based on the solid content of Toray Dow Corning Silicone Co., Ltd.
The carrier core material was mixed and coated with 1.5% by weight of the carrier core material in the same manner as in Example 1, and further baked at 280 ° C. for 3 hours to obtain a carrier coated with the above resin.

Using this carrier and each toner used in Example 1, a developer having a toner concentration of 8.0% by weight was prepared for each color, and CF-70 (manufactured by Minolta Camera Co.) was used.
The printing durability was evaluated. Table 2 shows the image evaluation at that time.

Example 5 As shown in Table 1, ferrite particles (trade name: F-
2535, manufactured by Powder Tech Co., Ltd., with an average particle size of 60
μm, surface property index 1.5 (BET specific surface area: 347c
m ² / g, air permeation method specific surface area: 231 cm ² / g) and a silicone resin (trade name: SR-
2411, solid content 20% by weight, Toray Dow Corning
12% by weight of γ-aminopropyltriethoxysilane (amino equivalent: 221) was mixed with the solid content of Silicone Co., Ltd., and 0.8% by weight was coated on the carrier core material in the same manner as in Example 1. Then, baking was further performed at 240 ° C. for 3 hours to obtain a carrier coated with the above resin.

Using this carrier and each toner used in Example 1, a developer having a toner concentration of 8.0% by weight was prepared for each color, and CF-70 (manufactured by Minolta Camera) was used.
The printing durability was evaluated. Table 2 shows the image evaluation at that time.

Example 6 As shown in Table 1, ferrite particles (trade name: F-
3040, manufactured by Powder Tech Co., Ltd., using an average particle size of 47
μm, surface property index 1.8 (BET method specific surface area: 557 c
m ² / g, air permeation method specific surface area: 310 cm ² / g) and a silicone resin (trade name: SR-
2411, solid content 20% by weight, Toray Dow Corning
6% by weight of γ-aminopropyltriethoxysilane (amino equivalent: 221) based on the solid content of Silicone Co., Ltd.
After mixing, the carrier core material was coated with 0.3% by weight in the same manner as in Example 1, and further baked at 220 ° C. for 2 hours to obtain a carrier coated with the above resin.

Using this carrier and each toner used in Example 1, a developer having a toner concentration of 8.0% by weight was prepared for each color, and CF-70 (manufactured by Minolta Camera Co., Ltd.) was used for printing durability. An evaluation was made. The image evaluation at that time is shown in Table 2.
Shown in.

Example 7 As shown in Table 1, ferrite particles (trade name: F-
3035, manufactured by Powder Tech Co., Ltd., with an average particle size of 54
μm, surface property index 1.8 (BET specific surface area: 484c
m ² / g, air permeation method specific surface area: 270 cm ² / g) and a modified silicone resin (trade name: K
6% by weight of γ-aminopropyltrimethoxysilane (amino equivalent: 179) was added to the solid content of R-9706, solid content 50% by weight, manufactured by Shin-Etsu Chemical Co., Ltd., and the same method as in Example 1 was used. The carrier core material was coated with 0.4% by weight and baked at 220 ° C. for 3 hours to obtain a carrier coated with the above resin.

This carrier and each toner used in Example 1 were used to prepare a developer having a toner concentration of 8.0% by weight for each color, and CF-70 (manufactured by Minolta Camera Co., Ltd.) was used for printing durability. An evaluation was made. The image evaluation at that time is shown in Table 2.
Shown in.

Example 8 As shown in Table 1, ferrite particles (trade name: F-
1530, manufactured by Powder Tech Co., Ltd., with an average particle size of 85
μm, surface property index 1.1 (BET specific surface area: 188c
m ² / g, air permeation method specific surface area: 170 cm ² / g) and a modified silicone resin (trade name: K
6% by weight of γ-aminopropyltrimethoxysilane (amino equivalent: 179) was added to the solid content of R-9706, solid content 50% by weight, manufactured by Shin-Etsu Chemical Co., Ltd., and the same method as in Example 1 was used. The carrier core material was coated with 0.4% by weight and baked at 220 ° C. for 3 hours to obtain a carrier coated with the above resin.

Using this carrier and each toner used in Example 1, a developer having a toner concentration of 6.0% by weight was prepared for each color, and CF-70 (manufactured by Minolta Camera Co., Ltd.) was used for printing durability. An evaluation was made. The image evaluation at that time is shown in Table 2.
Shown in.

Example 9 As shown in Table 1, ferrite particles (trade name: F-
400, manufactured by Powder Tech Co., Ltd., with an average particle size of 30μ
m, surface property index 3.5 (BET specific surface area: 2075c
m ² / g, air permeation method specific surface area: 592 cm ² / g) and a modified silicone resin (trade name: K
R-9706, solid content 50% by weight, manufactured by Shin-Etsu Chemical Co., Ltd.) 25% by weight of γ-aminopropylmethyldimethoxysilane (amino equivalent: 163) was mixed with the solid content, and in the same manner as in Example 1, The carrier core material was coated with 2.1% by weight and further baked at 280 ° C. for 3 hours to obtain a carrier coated with the above resin.

Using this carrier and each toner used in Example 1, a developer having a toner concentration of 8.0% by weight was prepared for each color, and CF-70 (manufactured by Minolta Camera Co., Ltd.) was used for printing durability. An evaluation was made. The image evaluation at that time is shown in Table 2.
Shown in.

Comparative Example 1 As shown in Table 1, the carrier core material used in Example 1 was used and a silicone resin (trade name: SR-241) was used.
1. Solid content 20% by weight, 3% by weight of γ-aminopropylmethyldimethoxysilane (amino equivalent: 163) was mixed with the solid content of Toray Dow Corning Silicone Co., Ltd., and the same method as in Example 1 A carrier was obtained by coating and baking with the same amount of resin.

This carrier was prepared as a developer in the same manner as in Example 1, and the printing durability was evaluated using the same machine.
Table 2 shows the image evaluation at that time.

Comparative Example 2 As shown in Table 1, the carrier core material used in Example 1 was used, and a silicone resin (trade name: SR-241) was used.
30% by weight of γ-aminopropylmethyldimethoxysilane (amino equivalent: 163) based on the solid content of 1, 20% by weight of solid content, manufactured by Toray Dow Corning Silicone Co., Ltd.
After mixing, coating and baking were carried out in the same manner as in Example 1 and with the same amount of resin to obtain a carrier.

This carrier was prepared as a developer in the same manner as in Example 1, and printing durability was evaluated using the same machine.
Table 2 shows the image evaluation at that time.

Comparative Example 3 As shown in Table 1, using the carrier core material used in Example 7, N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane (amino equivalent: 103)
Was mixed with the same resin used in Example 7 in the same ratio, and the same method and the same amount of resin as in Example 7 were used for coating and baking to obtain a carrier.

This carrier was prepared into a developer in the same manner as in Example 7, and printing durability was evaluated using the same machine.
Table 2 shows the image evaluation at that time.

Comparative Example 4 As shown in Table 1, using the carrier core material used in Example 7, γ-N-phenylaminopropyltrimethoxysilane (amino equivalent: 255) was used in Example 7. The same resin was mixed in the same ratio as in No. 1 and coated and baked by the same method and the same amount of resin as in Example 7 to obtain a carrier.

This carrier was prepared as a developer in the same manner as in Example 7, and the printing durability was evaluated using the same machine.
Table 2 shows the image evaluation at that time.

Comparative Example 5 As shown in Table 1, ferrite particles (trade name: F-
8020, manufactured by Powder Tech Co., Ltd., with an average particle size of 15
0 μm, surface property index 1.3 (BET specific surface area: 146
cm ² / g, air permeation method specific surface area: 113 cm ² / g) and a silicone resin (product name: SR
-2411, solid content 20% by weight, manufactured by Toray Dow Corning Silicone Co., Ltd.) to 3 solids of γ-aminopropylmethyldimethoxysilane (amino equivalent: 163).
0% by weight was mixed, and 0.3% by weight was coated on the carrier core material in the same manner as in Example 1, and further 200 ° C.
Baking for 2 hours to obtain a carrier coated with the above resin.

Using this carrier and each toner used in Example 1, a developer having a toner concentration of 5.0% by weight was prepared for each color, and CF-70 (manufactured by Minolta Camera Co., Ltd.) was used for printing durability. An evaluation was made. The image evaluation at that time is shown in Table 2.
Shown in.

Comparative Example 6 As shown in Table 1, ferrite particles (trade name: F-
2035, manufactured by Powder Tech Co., Ltd., with an average particle size of 65
μm, surface property index 5.5 (BET specific surface area: 1750
cm ² / g, air permeation method specific surface area: 318 cm ² / g) and a silicone resin (trade name: SR
-2411, solid content 20% by weight, manufactured by Toray Dow Corning Silicone Co., Ltd.) to 3 solids of γ-aminopropylmethyldimethoxysilane (amino equivalent: 163).
0% by weight was mixed, and 0.3% by weight was coated on the carrier core material in the same manner as in Example 1, and further 200 ° C.
Baking for 2 hours to obtain a carrier coated with the above resin.

Using this carrier and each toner used in Example 1, a developer having a toner concentration of 8.0% by weight was prepared for each color, and CF-70 (manufactured by Minolta Camera Co., Ltd.) was used for printing durability. An evaluation was made. The image evaluation at that time is shown in Table 2.
Shown in.

Comparative Example 7 As shown in Table 1, ferrite particles (trade name: F-
500, manufactured by Powder Tech Co., Ltd., average particle size 17μ
m, surface property index 5.5 (BET specific surface area: 4854c
m ² / g, air permeation method specific surface area: 883 cm ² / g) and a silicone resin (trade name: SR-
2411, solid content 20% by weight, Toray Dow Corning
3% by weight of γ-aminopropylmethyldimethoxysilane (amino equivalent: 163) was mixed with the solid content of Silicone Co., Ltd., and 5.0% by weight was coated on the carrier core material in the same manner as in Example 1. And then at 180 ° C for 2
After baking for a period of time, a carrier coated with the above resin was obtained.

Using this carrier and each toner used in Example 1, a developer having a toner concentration of 9.0% by weight was prepared for each color, and CF-70 (manufactured by Minolta Camera Co.) was used for printing durability. An evaluation was made. The image evaluation at that time is shown in Table 2.
Shown in.

Comparative Example 8 As shown in Table 1, the carrier core material used in Example 1 was used, and a silicone resin (trade name: SR-241) was used.
1. Solid content 20% by weight, manufactured by Toray Dow Corning Silicone Co., Ltd.) was dissolved in a toluene solvent, and then 0.7% by weight was coated on the carrier core material using a fluidized bed. At that time, γ-aminopropylmethyldimethoxysilane was gradually added to the silicone resin solution so that the concentration of γ-aminopropylmethyldimethoxysilane was gradually decreased, and the concentration of the aminosilane coupling agent was changed to the silicone resin. On the other hand, it was coated so as to have a concentration gradient. Further, γ-aminopropylmethyldimethoxysilane was added in an amount of 8% by weight in total with respect to the silicone resin. Further, it was baked at 200 ° C. for 2 hours to obtain a carrier coated with the above resin.

This carrier was prepared as a developer in the same manner as in Example 1, and printing durability was evaluated using CF-70 (manufactured by Minolta Camera Co., Ltd.). The image evaluation at that time is shown in Table 2.
Shown in.

[0093]

[Table 1] * 1: Ratio of aminosilane coupling agent in the coating resin. * 2: Has a concentration gradient.

[0094]

[Table 2]

[0095]

INDUSTRIAL APPLICABILITY As described above, the carrier of the present invention and the developer using the carrier include a coating resin composed of a silicone resin or a modified silicone resin in which an aminosilane coupling agent is contained in a carrier core material. By controlling the content ratio of the aminosilane coupling agent in the coating resin layer and the amino equivalent of the aminosilane coupling agent within a certain range, the toner has excellent environmental stability and can be supplied to the toner supplied during printing. Thus, it is possible to obtain a carrier and a developer which have good charging rise and can be instantly imparted with charging ability. Further, the carrier having the above characteristics can be satisfactorily obtained by the manufacturing method of the present invention.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshio Honjo 217, Toyoji Juyo, Kashiwa City, Chiba Prefecture

Claims (7)

[Claims] 1. A carrier core material has a coating resin layer made of a silicone resin or a modified silicone resin containing an aminosilane coupling agent, and the content ratio of the aminosilane coupling agent in the coating resin is 6 to 6. 25% by weight, and the amino equivalent of the aminosilane coupling agent is 1
63 to 235. A resin coated carrier for an electrophotographic developer, characterized in that 2. The resin coated carrier for an electrophotographic developer according to claim 1, wherein the aminosilane coupling agent has an aliphatic structure having a primary amino group represented by the following structural formula. [Chemical 1] (However, R ₁ is an alkylene group having 1 to 4 carbon atoms, R ₂ , R ₃
Is an alkyl group having 1 to 2 carbon atoms, n = 2 or 3) 3. The surface property index of the carrier core material is 1.0.
To 2.1, and the average particle size is 20 to 100.
The resin-coated carrier for an electrophotographic developer according to claim 1, which has a thickness of μm. 4. The content ratio of the aminosilane coupling agent is 12 to 22% by weight, and the amino equivalent of the aminosilane coupling agent is 179 to 221.
Alternatively, the resin-coated carrier for electrophotographic developer according to Item 3. 5. The electrophotographic developer according to claim 3, wherein the surface property index of the carrier core material in the coating resin is in the range of 1.5 to 2.0, and the average particle size is 30 to 65 μm. Resin coated carrier. 6. The total amount of the aminosilane coupling agent in the silicone resin or modified silicone resin is 6 to 2
5% by weight, and this is dissolved in a solvent to form a resin solution, and the resin solution is uniformly applied to a carrier core material to form a coating resin layer, and then the coating resin layer is formed at 180 to 300 ° C. A method for producing a resin-coated carrier for an electrophotographic developer, which comprises baking. 7. An electrophotographic developer comprising the carrier according to claim 1, and the carrier and a non-magnetic toner.