JP2009025676A - Resin coated toner carrier for electrophotography and method for manufacturing the same, developer, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin coated toner carrier for electrophotography and a method for manufacturing the carrier improved in charging characteristics, developing characteristics and lifetime characteristics without using a tin organic compound that is a controlled substance, and to provide a developer and an image forming apparatus. <P>SOLUTION: A toner carrier core 110 having a structure of aggregated particles is produced by sintering an oxide magnetic material; a coating resin liquid is prepared by dissolving a silicone-based resin (A) soluble with an organic solvent having compatibility with water, an amino-based silane coupling agent (B), an epoxy-based silane coupling agent (C) and water (D) in an organic solvent having compatibility with water; and the carrier core particles are coated with the resin coating liquid to form a silicone-based resin coating layer 120. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a resin-coated toner carrier for electrophotography, a method for producing the same, a developer, and an image forming apparatus, and more particularly, an oxide magnetic material having carrier particles exhibiting a structure of sintered aggregated particles. The present invention relates to an electrophotographic resin-coated toner carrier and a method for producing the same, a developer using the toner carrier, and an image forming apparatus for forming an image using the developer.

  Conventional electrophotographic methods include a one-component development method and a two-component development method. Each will be described below. The one-component development method is a development method in which an electrostatic latent image is developed on a paper surface or the like using only magnetic toner. The two-component development method is a development method in which an electrostatic latent image is developed on a paper surface or the like using toner and a toner carrier (so-called carrier), and is excellent in high-speed and high-quality processing and low in printing cost. Therefore, it is suitable for a large amount of printing processing.

  In general, the two-component development method is characterized in that the toner carrier is in charge of transporting the toner and the like, and the functions are easily controlled because the functions are separated as a developer. The two-component development method will be described in detail. The toner carrier and toner are abraded and charged oppositely (reverse polarity) by stirring and mixing the toner carrier having chargeability and magnetic duality and the toner having chargeability. Then, after the toner is electrically attached on the toner carrier, the toner is dispersed on the magnet roller by magnetism to form a magnetic brush. Next, the toner is electrically partially attached onto a photosensitive drum formed of a photoconductive material and having a latent image (electrostatic latent image) formed thereon by a predetermined method.

  In recent years, with the demands for higher image quality and higher speed of image forming apparatuses and longer life of toner carriers and developers, magnetic properties such as saturation magnetization and holding power for toner carriers, charging characteristics, development characteristics, and life characteristics Improvement is becoming important (see, for example, Non-Patent Document 1).

  The charging and developing characteristics are described below. The charge amount is generated by stirring and mixing the toner carrier and the toner, and the charge amount of the toner is stably generated to maintain the printing quality. Can do. There are two types of toner: monochrome printing and color printing. One monochrome toner is used for monochrome printing, and four colors (black, yellow, magenta, and cyan) are used for color printing.

  The image quality of printing is determined only by the charge amount of black toner in monochrome printing, but is determined by the charge amount of toner of four colors (black, yellow, magenta, cyan) in color printing. If there is a difference in charge amount (charge amount difference), the image quality is greatly affected. In general, black toner tends to have a higher charge amount than the other three colors. The reason for the difference in the charge amounts of the four color toners is that the charge properties of the coating resin applied to the toner carrier surface and the respective toners are different due to stirring and mixing.

  As a countermeasure against the difference in charge amount, a method using a commercially available silicone resin solution SR-2411 (manufactured by Toray Dow Corning) for coating, to which a curing agent of a tin organic compound is added (for example, see Patent Document 1). It is common. In order to control the value of the charge amount, an amino silane coupling agent, a fluorine silane coupling agent, or the like is used.

  Regarding the life characteristics, the causes of the toner carrier deterioration with time include wear and peeling due to stirring and mixing with the toner, and dirt (spent) of the resin coated on the toner carrier surface. The amount of charge decreases (for example, see Non-Patent Document 2 and Non-Patent Document 3). As countermeasures, improvement of the coating resin, weight reduction and spheroidization of the toner carrier have been performed (see, for example, Non-Patent Document 2). Among these, the improvement of the coating resin includes the use of a silicone resin with low surface energy (measures for spent), the improvement of hardness by the addition of a tin organic compound to the silicone resin (measures against wear) and the use of silane coupling agents. Addition improves adhesion to the toner carrier core (measures against peeling) (see, for example, Patent Documents 2 and 3).

  Conventionally, the toner carrier or the developing device is changed every thousands to tens of thousands of printed sheets, and it is necessary to construct the management and maintenance costs of the equipment and the service system. There is a problem. In addition, with the recent trend toward higher image quality and higher speed, there is a strong demand for the life of toner carriers to be as close as possible to the life of machine bodies such as multifunction peripherals and copiers. Yes.

In addition to the above-described improvements in charging characteristics, development characteristics, and life characteristics, as a countermeasure for the toner carrier core material, a binder-type toner carrier is used (for example, see Patent Document 4), and a depression is provided on the core surface by special processing. And the like (for example, refer to Patent Document 5), and the like (for example, refer to Patent Document 6) in which the surface of the toner carrier core material is smoothed by composition control.
Journal of the Imaging Society of Japan, Vol. 43, No. 5, P356-363 (2004) Konica Technical Report, VOL. 11, P356-363 (1998) Konica Technical Report, VOL. 14, P356-363 (2001) Japanese Patent No. 3162887 Japanese Patent No. 2901701 Japanese Patent Laid-Open No. 60-19156 JP-A-62-212463 Japanese Patent No. 2933780 Japanese Patent No. 1776809

  However, in the above conventional technology, as described above (Patent Document 1), tin organic compounds (dibutyltin compounds) used as an effective curing agent for improving the improvement in charging characteristics, development characteristics, and life characteristics are not regulated substances. Some tributyltin compounds are included and may not be usable in the future.

  In addition, as described above (Patent Document 2), the addition of an amino-based silane coupling agent can improve the adhesion to the toner carrier core and the charge amount, but the image quality can be improved by changing the charge amount in various environments. It has the problem of being lowered.

  In addition, as described above (Patent Document 3), although the adhesion to the toner carrier core can be improved by coating the surface of the toner carrier core with an amino silane coupling agent, the charge amount is improved on the surface of the toner carrier coating resin. Since there are few amino groups to be formed and there is not sufficient charging ability, there is a problem that the image quality of printing is deteriorated.

  In addition, some of the ones employing the binder-type toner carrier as described above (Patent Document 4) exhibit excellent performance in terms of life, but it is difficult to obtain one with high saturation magnetization, and the manufacturing cost is high. There is a problem.

  Further, the surface of the toner carrier core material is improved by providing a depression on the core surface as described above (Patent Document 5) or by smoothing the surface of the toner carrier core material as described above (Patent Document 6). In that case, it is necessary to add many new processes to the conventional method. Therefore, it can be considered that the yield and cost are affected.

  The present invention solves such a conventional problem, and does not use a tin organic compound as a curing agent for a silicone-based resin, and provides a longer life by improving charging characteristics, development characteristics, and life characteristics. It is an object of the present invention to provide a toner carrier and a manufacturing method thereof.

  Further, the present invention does not use a tin organic compound, which is a regulated substance, as a curing agent for a silicone resin, and has a toner carrier that provides a long life by improving charging characteristics, development characteristics, and life characteristics. It is an object of the present invention to provide an image forming apparatus that forms an image using the developer and the developer.

  In order to solve the above-mentioned problems, the present invention produces carrier core particles having a structure of aggregated particles by sintering an oxide magnetic material, and an organic solvent compatible with water is used as an organic solvent compatible with water. Solvent-soluble silicone resin (A), amino silane coupling agent (B), epoxy silane coupling agent (C), and water (D) are dissolved to produce a coating resin solution. Then, the carrier core particles are coated with a coating resin solution to form a coating resin layer.

  According to the present invention, without using a tin organic compound that is a regulating substance as a curing agent, while maintaining the adhesiveness with the toner carrier core, by improving the crosslinkability of the silicone resin, charging characteristics, An electrophotographic resin-coated toner carrier having improved development characteristics and life characteristics can be obtained.

  According to a first aspect of the present invention, there is provided a method for producing a resin-coated toner carrier for electrophotography, comprising preparing carrier core particles having a structure of aggregated particles by sintering an oxide magnetic material, and being compatible with water. In addition, a silicone resin (A) soluble in an organic solvent compatible with water, an amino silane coupling agent (B), an epoxy silane coupling agent (C), water (D), A coating resin liquid is prepared, and the carrier core particles are coated with the coating resin liquid to form a coating resin layer, and a tin organic compound which is a regulated substance as a curing agent Without using the toner, it has an effect of improving the crosslinkability of the silicone resin while maintaining the adhesion to the toner carrier core. That is, without using a tin organic compound that is a regulated substance as a curing agent, while maintaining adhesion to the carrier core, the amino group that is an organic functional group of the amino silane coupling agent and the epoxy silane coupling agent Crosslinking property of silicone resin by promoting the hydrolysis of alkoxy group of amino silane coupling agent and epoxy silane coupling agent by high crosslinking by epoxy ring-opening polymerization reaction of organic functional group and addition of water It has the effect | action of improving. For this reason, it has excellent image quality (improves charging characteristics and development characteristics: small difference in charge amount with respect to color toner), and excellent life characteristics (improves stain resistance, abrasion resistance, and peel resistance of coating resin) An electrophotographic resin-coated toner carrier capable of forming a silicone resin film is obtained.

  The method for producing a resin-coated toner carrier for electrophotography according to the second invention is the method according to the first invention, wherein the amino silane coupling agent (B) and the epoxy silane coupling agent (B) are hydrolyzed with three. It is characterized by having a functional group, improves the crosslinkability of the silicone resin (three-dimensional crosslinking), and adheres to the toner carrier core without using a tin organic compound that is a regulated substance as a curing agent. This has the effect of further improving the crosslinkability of the silicone-based resin while maintaining the properties. For this reason, it has excellent image quality (improves charging characteristics and development characteristics: small difference in charge amount with respect to color toner), and excellent life characteristics (improves stain resistance, abrasion resistance, and peel resistance of coating resin) An electrophotographic resin-coated toner carrier capable of forming a silicone resin film is obtained.

  The resin-coated toner carrier for electrophotography of the third invention is the weight ratio of the amino silane coupling agent (B) to the epoxy silane coupling agent (C) in the first invention or the second invention. The range of (C / B) is 1 to 3, while maintaining the adhesion to the toner carrier core without using a tin organic compound, which is a regulated substance, as a curing agent. And has the effect of further improving the crosslinkability of the silicone resin. For this reason, it has excellent image quality (improves charging characteristics and development characteristics: small difference in charge amount with respect to color toner), and excellent life characteristics (improves stain resistance, abrasion resistance, and peel resistance of coating resin) An electrophotographic resin-coated toner carrier capable of forming a silicone resin film is obtained.

  A resin-coated toner carrier for electrophotography according to a fourth aspect of the present invention is manufactured by the manufacturing method according to any one of the first to third aspects, and is a controlled substance as a curing agent. Without using a tin organic compound, the crosslinkability of the silicone resin is improved while maintaining adhesion to the toner carrier core. That is, without using a tin organic compound that is a regulated substance as a curing agent, while maintaining adhesion to the carrier core, the amino group that is an organic functional group of the amino silane coupling agent and the epoxy silane coupling agent Crosslinking property of silicone resin by promoting the hydrolysis of alkoxy group of amino silane coupling agent and epoxy silane coupling agent by high crosslinking by epoxy ring-opening polymerization reaction of organic functional group and addition of water Has the effect of improving. For this reason, it has excellent image quality (improves charging characteristics and development characteristics: small difference in charge amount with respect to color toner), and excellent life characteristics (improves stain resistance, abrasion resistance, and peel resistance of coating resin) An electrophotographic resin-coated toner carrier capable of forming a silicone resin film is obtained.

  The developer of the fifth invention has a constitution having the resin-coated toner carrier for electrophotography according to any one of the fourth invention, and has electric characteristics and development characteristics as compared with the conventional case. It has an effect that it can be provided as a two-component developer for electrophotography having excellent life characteristics. In addition, since the deterioration of the carrier or developer can be suppressed, the frequency of replacement of the carrier or developer can be reduced.

  The image forming apparatus of the sixth invention is characterized in that an image is formed using the developer described in the fifth invention, and charging characteristics, development characteristics, life characteristics are compared with the conventional case. By using a two-component developer for electrophotography using a resin-coated toner carrier for electrophotography with an improved image quality, it is possible to provide an image forming apparatus corresponding to higher image quality, higher speed, and longer life. For the end user, there is an effect that the frequency of replacement of the developer can be reduced and the maintenance service cost for the developer can be suppressed.

  Embodiments of the present invention will be described below.

(Embodiment 1)
Embodiments 1 to 5 of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing an example of the structure of the toner carrier of the present invention. FIG. 2 is an electron micrograph showing an example of the shape of the toner carrier core (one piece) before coating, FIG. 3 is an electron micrograph showing an example of the shape of the toner carrier core (one piece) after coating, and FIG. 4 is an electron micrograph showing an example of a shape of a toner carrier (whole) afterwards.

  In FIG. 1, 100 is an electrophotographic toner carrier particle, 110 is a toner carrier core of the electrophotographic toner carrier particle 100, and 120 is a silicone resin coating layer that is a coating resin layer formed on the surface of the toner carrier core 110. is there. As shown in FIG. 1, the toner carrier core 110 of the electrophotographic toner carrier particle 100 is an oxide magnetic body, has a structure of sintered aggregated particles, and has an average particle diameter of 25 μm to 150 μm. .

The surface of the toner carrier core 110 is coated with a silicone resin as the silicone resin coating layer 120. The silicone-based resin coating layer 120 has a range of 10-50% by weight of the silicone-based resin (A) soluble in an organic solvent compatible with water. The amino-based silane coupling agent (B) and the epoxy-based silane cup Coating resin dissolved in an organic solvent compatible with water so that the total (B + C) range of the ring agent (C) is 5 to 50% by weight and H ₂ O (D) is 20 to 90% by weight. It is coated with a liquid.

  In order to control the resistance value of the toner carrier, the surface of the silicone-based resin coating layer 120 may be coated with a high-resistance coating resin on a part of the surface of the low-resistance toner carrier core 110 or a high-resistance coating resin. In some cases, a conductive agent is added to cover the entire surface with resin.

  The adhesiveness at the boundary between the toner carrier core 110 and the silicone resin coating layer 120 is based on the anchor effect due to the unevenness of the surface of the toner carrier core 110 and the strong chemical properties due to the amino silane coupling agent and the epoxy silane coupling agent. The structure is caused by bonding and is difficult to peel off.

  The chemical bonding by the amino silane coupling agent and the epoxy silane coupling agent will be explained. Hydrolyzable groups of the amino silane coupling agent and the epoxy silane coupling agent added to the silicone resin are hydrolyzed. It becomes a silanol group and dehydrates with a hydroxyl group on the surface of the toner carrier core 110 to form a strong chemical bond.

  Since the silicone-based resin coating layer 120 forms a high-hardness resin layer having a high-dimensional structure of a silicone-based resin, the silicone-based resin coating layer 120 has excellent characteristics against peeling and abrasion, and prevents deterioration of charging property with time. . Further, the formation of a high-hardness resin layer having a high-dimensional structure of a silicone-based resin can reduce the charge amount difference of the color toner and improve the image quality.

(Embodiment 1)
As Embodiment 1 of the present invention, an embodiment of the toner carrier shown in FIG. 1 will be described. The toner carrier core uses MgO, Mn ₃ O ₄ , Fe ₂ O ₃ as an oxide raw material (oxide magnetic material) and has a molar ratio of MgO: Mn ₃ O ₄ : Fe ₂ O ₃ = 10: 35: 55. The composition was prepared by blending so that This blend was wet-mixed and pulverized with a ball mill, dried, and calcined at 950 ° C. Add 50 wt% to 100 wt% of water and a water-based dispersant and a polyvinyl alcohol (PVA) binder for viscosity adjustment to the pre-fired blend, and pulverize again with a ball mill for several hours. A slurry was prepared. The dispersant was 0.1 to 1%, the binder was 1% to 2% in terms of solid content, and the finished slurry viscosity was in the range of 300 cP to 500 cP. This slurry was dried and granulated with a spray dryer, and after classification, a granulated powder of 40 to 125 μm was produced.

  The granulated powder is fired in a nitrogen-oxygen atmosphere at 1000 ° C. to 1350 ° C., pulverized into single particles by wet pulverization by pot rotation, and then classified again, and a toner carrier core material having an average particle size of 45 μm to 90 μm Was made.

Next, silicone resin YR3370 (manufactured by GE Toshiba Silicone) is dissolved in ethanol, amino silane coupling agent KBM-602 (manufactured by Shin-Etsu Chemical), epoxy-based silane coupling agent KBE-402 (manufactured by Shin-Etsu Chemical), H ₂ O-added silicone resin coating solution is uniformly applied to the toner carrier core and baked at 200 ° C. to 240 ° C., and a toner carrier sample (Example) is prepared so that the charge amount is about 35 μC / g. Produced.

  As an example, three types of silicone resin coating liquids were prepared by changing the addition amount (mixing ratio) of the epoxy silane coupling agent KBE-402 (manufactured by Shin-Etsu Chemical Co., Ltd.), and uniformly applied to the toner carrier core. Thus, three types of toner carrier samples (Example 1, Example 2, and Example 3) were produced. Detailed production conditions of three types of toner carrier samples (Example 1, Example 2, and Example 3) are shown in Table 1.

In addition, an epoxy-based silane coupling agent KBE-402 (manufactured by Shin-Etsu Chemical) or a silicone resin coating solution to which H ₂ O is not added is evenly applied to the toner carrier core and baked at 200 ° C. to 240 ° C. for charging. A toner carrier sample (comparative example) was prepared so that the amount was about 35 μC / g.

As a comparative example, three types of silicone resin coating liquids were prepared by changing the addition amount (mixing ratio) of the epoxy silane coupling agent KBE-402 (manufactured by Shin-Etsu Chemical) or H ₂ O. By applying uniformly, three types of toner carrier samples (Comparative Example 1, Comparative Example 2, and Comparative Example 3) were produced. Table 1 shows the detailed production conditions of three types of toner carrier samples (Comparative Example 1, Comparative Example 2, and Comparative Example 3) for the toner carrier core 250g.

  These toner carriers were evaluated. As an evaluation method, 46.5 g of the toner carrier sample and 3.5 g of the toner are put in a plastic container having a length of 8 cm and a diameter of 4 cm, and the plastic container is mixed by rotating at 100 rpm, and the rotation mixing time is 10 minutes. The change with time in the charge amount was measured at 30 minutes and 60 minutes.

  As the toner, a black toner or a magenta toner for a color printing machine was used, and when the respective toners were used, a comparison was made between a difference in charge amount of toner and a change in charge amount with time. The charge amount is shown as a relative value of the charge amount, assuming that the charge amount at 10 minutes when black toner is used is 100%. The measurement results are also shown in (Table 1).

As can be seen from Table 1, the relative value of the charge amount is higher for the black toner than for the magenta toner in each of the examples and comparative examples. The smaller the charge amount difference, the better the image quality. From this, the toner carrier of Examples 1 to 3 to which the epoxy silane coupling agent KBE-402 (manufactured by Shin-Etsu Chemical) and H ₂ O were added was the epoxy-based silane coupling agent KBE-402 (manufactured by Shin-Etsu Chemical). Alternatively, it can be said that the image quality is better than the toner carriers of Comparative Examples 1 to 3 to which H ₂ O is not added.

  As can be seen from (Table 1), the relative value of the charge amount decreases with the passage of time. This is considered to be because the silicone resin coating layer 120 is worn or peeled off by rotating and mixing the toner carrier with the toner, or the surface of the silicone resin coating layer 120 is contaminated with the toner. The smaller the change over time in the relative value of the charge amount, the longer the life of the toner carrier.

Therefore, the toner carriers of Examples 1 to 3 to which the epoxy silane coupling agent KBE-402 (manufactured by Shin-Etsu Chemical) and H ₂ O are added are epoxy silane coupling agent KBE-402 (manufactured by Shin-Etsu Chemical) or It can be said that the lifetime is longer than that of the toner carriers of Comparative Examples 1 to 3 to which H ₂ O is not added.

(Embodiment 2)
As a second embodiment of the present invention, an embodiment of the toner carrier shown in FIG. 1 will be described. The toner carrier core uses MgO, Mn ₃ O ₄ , Fe ₂ O ₃ as an oxide raw material (oxide magnetic material) and has a molar ratio of MgO: Mn ₃ O ₄ : Fe ₂ O ₃ = 10: 35: 55. The composition was prepared by blending so that This blend was wet-mixed and pulverized with a ball mill, dried, and calcined at 950 ° C. A water-based dispersant and a PVA-based binder were added to adjust the viscosity of 50 wt% to 100 wt% of water, and the mixture was pulverized again for several hours with a ball mill to prepare a slurry. The dispersant was 0.1 to 1%, the binder was 1% to 2% in terms of solid content, and the finished slurry viscosity was in the range of 300 cP to 500 cP. This slurry was dried and granulated with a spray dryer, and after classification, a granulated powder of 40 to 125 μm was produced.

  The granulated powder is fired in a nitrogen-oxygen atmosphere at 1000 ° C. to 1350 ° C., pulverized into single particles by wet pulverization by pot rotation, and then classified again, and a toner carrier core material having an average particle size of 45 μm to 125 μm Was made.

Next, silicone resin YR3370 (manufactured by GE Toshiba Silicone) is dissolved in ethanol, and amino silane coupling agent (KBM-602 (manufactured by Shin-Etsu Chemical Co., Ltd.) having two hydrolyzable groups) and three hydrolyzable groups. KBM-603 (manufactured by Shin-Etsu Chemical)), epoxy-based silane coupling agent (KBE-402 (manufactured by Shin-Etsu Chemical) having two hydrolyzable groups) and KBM-403 (manufactured by Shin-Etsu Chemical) having three hydrolyzable groups )), A silicone resin coating solution to which H ₂ O is optionally added is uniformly applied to the toner carrier core and baked at 200 ° C. to 240 ° C. so that the charge amount is about 35 μC / g. Samples (Examples and Comparative Examples) were prepared.

  As an example, KBM-603 (manufactured by Shin-Etsu Chemical Co., Ltd.) having three hydrolyzable groups was used as an amino silane coupling agent, and KBM-403 (manufactured by Shin-Etsu Chemical Co., Ltd.) having three hydrolyzable groups was used as an epoxy silane. By using it as a coupling agent, changing the addition amount (mixing ratio) of the epoxy-based silane coupling agent KBM-403 to produce three types of silicone resin coating liquids, and uniformly coating the toner carrier core, Three types of toner carrier samples (Example 4, Example 5, and Example 6) were prepared. Table 2 shows the detailed production conditions of three types of toner carrier samples (Example 4, Example 5, and Example 6) for the toner carrier core 250g.

  As a comparative example, KBM-602 (manufactured by Shin-Etsu Chemical) having two hydrolyzable groups was used as an amino silane coupling agent, and KBE-402 (manufactured by Shin-Etsu Chemical) having two hydrolyzable groups was used as an epoxy silane. By using it as a coupling agent, changing the addition amount (mixing ratio) of the epoxy-based silane coupling agent KBE-402 to prepare three types of silicone resin coating liquids, and uniformly coating the toner carrier core, Three types of toner carrier samples (Comparative Example 4, Comparative Example 5, and Comparative Example 6) were prepared. Table 3 shows the detailed production conditions of three types of toner carrier samples (Comparative Example 4, Comparative Example 5, and Comparative Example 6) for the toner carrier core 250g.

  These toner carriers were evaluated. As an evaluation method, 46.5 g of the toner carrier sample and 3.5 g of the toner are put in a plastic container having a length of 8 cm and a diameter of 4 cm, and the plastic container is mixed by rotating at 100 rpm, and the rotation mixing time is 10 minutes. The change with time in the charge amount was measured at 30 minutes and 60 minutes.

  As the toner, a black toner or a magenta toner for a color printing machine was used, and when the respective toners were used, a comparison was made between a difference in charge amount of toner and a change in charge amount with time. The charge amount is shown as a relative value of the charge amount, assuming that the charge amount at 10 minutes when black toner is used is 100%. The measurement results are also shown in (Table 2) and (Table 3).

As can be seen from (Table 2) and (Table 3), as for the relative value of the charge amount, the value of the black toner is higher than the value of the magenta toner in each of the examples and the comparative examples. The smaller the charge amount difference, the better the image quality. Therefore, an amino silane coupling agent KBM-603 (manufactured by Shin-Etsu Chemical) having three hydrolyzable groups and an epoxy silane coupling agent KBE-403 (manufactured by Shin-Etsu Chemical) having three hydrolyzable groups, The toner carriers of Examples 4 to 6 to which H ₂ O was added were an amino silane coupling agent KBM-602 (manufactured by Shin-Etsu Chemical Co., Ltd.) having two hydrolyzable groups and an epoxy silane having two hydrolyzable groups. It can be said that the image quality is better than the toner carriers of Comparative Examples 1 to 3 to which a coupling agent KBE-402 (manufactured by Shin-Etsu Chemical Co., Ltd.) and H ₂ O are added.

(Embodiment 3)
As the third embodiment of the present invention, an embodiment of the toner carrier shown in FIG. 1 will be described. The toner carrier core uses MgO, Mn ₃ O ₄ , Fe ₂ O ₃ as an oxide raw material (oxide magnetic material) and has a molar ratio of MgO: Mn ₃ O ₄ : Fe ₂ O ₃ = 10: 35: 55. The composition was prepared by blending so that This blend was wet-mixed and pulverized with a ball mill, dried, and calcined at 950 ° C. A water-based dispersant and a PVA-based binder were added to adjust the viscosity of 50 wt% to 100 wt% of water, and the mixture was pulverized again for several hours with a ball mill to prepare a slurry. The dispersant was 0.1 to 1%, the binder was 1% to 2% in terms of solid content, and the finished slurry viscosity was in the range of 300 cP to 500 cP. This slurry was dried and granulated with a spray dryer, and after classification, a granulated powder of 40 to 1125 μm was produced.

  The granulated powder is fired in a nitrogen-oxygen atmosphere at 1000 ° C. to 1350 ° C., pulverized into single particles by wet pulverization by pot rotation, and then classified again, and a toner carrier core material having an average particle size of 45 μm to 90 μm Was made.

Next, the silicone resin YR3370 (manufactured by GE Toshiba Silicone) is dissolved in ethanol, and the range of the weight ratio (C / B) between the amino silane coupling agent (B) and the epoxy silane coupling agent (C) is 1-3 become as amino-based Shirankappuri agent (KBM-603 (Shin-Etsu chemical Co., Ltd.)) and the epoxy-based silane coupling agent (KBE-403 (Shin-Etsu chemical Co., Ltd.)) H ₂ O and the optionally added silicone The resin coating liquid was uniformly applied to the toner carrier core and baked at 200 ° C. to 240 ° C. to prepare toner carrier samples (Examples and Comparative Examples) so that the charge amount was about 35 μC / g.

  As an example, the addition amount (mixing ratio) of the epoxy-based silane coupling agent (KBE-403 (manufactured by Shin-Etsu Chemical)) was changed so that the weight ratio (C / B) ranged from 1 to 3. A silicone resin coating solution was prepared and uniformly applied to the toner carrier core, thereby preparing three types of toner carrier samples (Example 6, Example 7, and Example 8). Detailed production conditions of three types of toner carrier samples (Example 6, Example 7, and Example 8) are shown in Table 4.

  As a comparative example, three types of silicone resin coating liquids were prepared by changing the addition amount (mixing ratio) of the epoxy-based silane coupling agent (KBE-403 (manufactured by Shin-Etsu Chemical)), and uniformly formed on the toner carrier core. By coating, two types of toner carrier samples (Comparative Example 7 and Comparative Example 8) were produced. Detailed production conditions of two types of toner carrier samples (Comparative Example 7 and Comparative Example 8) for the toner carrier core 250g are also shown in (Table 4).

  These toner carriers were evaluated. As an evaluation method, 46.5 g of the toner carrier sample and 3.5 g of the toner are put in a plastic container having a length of 8 cm and a diameter of 4 cm, and the plastic container is mixed by rotating at 100 rpm, and the rotation mixing time is 10 minutes. The change with time in the charge amount was measured at 30 minutes and 60 minutes.

  As the toner, a black toner or a magenta toner for a color printing machine was used, and when the respective toners were used, a comparison was made between a difference in charge amount of toner and a change in charge amount with time. The charge amount is shown as a relative value of the charge amount, assuming that the charge amount at 10 minutes when black toner is used is 100%. The measurement results are also shown in (Table 1).

As can be seen from Table 4, the relative value of the charge amount is higher for the black toner than for the magenta toner in each of the examples and comparative examples. The smaller the charge amount difference, the better the image quality. Therefore, an amino silane coupling agent KBM-603 (manufactured by Shin-Etsu Chemical) having three hydrolyzable groups and an epoxy silane coupling agent KBE-403 (manufactured by Shin-Etsu Chemical) having three hydrolyzable groups, In the toner carrier to which H ₂ O is optionally added, the weight ratio (C / B) of the amino silane coupling agent (B) and the epoxy silane coupling agent (C) is adjusted to be 1 to 3. It can be said that the toner carriers of Examples 6 to 8 have better image quality than the toner carriers of Comparative Examples 7 and 8 whose weight ratio (C / B) is out of the range.

  Further, as can be seen from (Table 4), the relative value of the charge amount decreases with the passage of time. This may be because the silicone resin coating layer 120 is worn or peeled off by rotating and mixing the toner carrier with the toner, or the surface of the silicone resin coating layer 120 is contaminated with the toner. The smaller the change over time in the relative value of the charge amount, the longer the life of the toner carrier.

Therefore, an amino silane coupling agent KBM-603 (manufactured by Shin-Etsu Chemical) having three hydrolyzable groups and an epoxy silane coupling agent KBE-403 (manufactured by Shin-Etsu Chemical) having three hydrolyzable groups, In the toner carrier to which H ₂ O is optionally added, the range of the weight ratio (C / B) of the amino silane coupling agent (B) and the epoxy silane coupling agent (C) is 1 to 3. It can be said that the adjusted toner carriers of Examples 6 to 8 have a longer life than the toner carriers of Comparative Examples 7 and 8 having a weight ratio (C / B) outside the range.

(Embodiment 4)
In the fourth embodiment, a developer using the toner carrier according to the present invention will be described. First, a core material for a toner carrier having the characteristics shown in (Table 5) in the same manner as in the first embodiment of MnMg based ferrite prepared using MgO, Mn ₃ O ₄ and Fe ₂ O ₃ as starting materials. Was made.

Next, the silicone resin YR3370 (manufactured by GE Toshiba Silicone) is dissolved in ethanol, and the weight ratio (C / B) of the amino silane coupling agent (B) and the epoxy silane coupling agent (C) becomes 2. adding hydrolyzable amino-based silane coupling agent KBM603 (manufactured by Shin-Etsu chemical) having three groups and epoxy-based silane coupling agent having three hydrolyzable groups KBE403 (manufactured by Shin-Etsu chemical) and H ₂ O as The silicone resin coating liquid thus applied was uniformly applied to the toner carrier core and baked at 200 to 240 ° C. to prepare a toner carrier sample (Example 7) so that the charge amount was about 35 μC / g.

In addition, a silicone resin YR3370 (manufactured by GE Toshiba Silicone) is dissolved in ethanol, and an amino silane coupling agent KBM602 (manufactured by Shin-Etsu Chemical Co., Ltd.) having two hydrolyzable groups is added thereto to add an epoxy silane coupling agent and H _A toner carrier sample (Comparative Example 1) is prepared by uniformly applying a silicone resin coating solution without addition of ₂ O to the toner carrier core and baking it at 200 ° C. to 240 ° C. so that the charge amount is about 35 μC / g. Was made.

  The properties of the electrophotographic toner carrier thus prepared were measured for the powder properties, magnetic properties, charge amount and resistance value. The measurement results are also shown in (Table 5).

  Further, 7% by weight of toner was added to the electrophotographic resin-coated toner carrier prepared as described above and stirred, and then a developer was obtained. This developer was put into a developing device of a medium speed type multifunction peripheral (image forming apparatus) employing a two-component developing method manufactured by Matsushita Electric Industrial Co., Ltd., and a printing test was conducted.

  As a result of this printing test, FIG. 5 shows the relationship between the number of printed sheets and the charge amount change rate when the developer using the toner carrier according to the present invention and the conventional developer are used. In FIG. 5, the solid line shows the characteristics when the developer having the toner carrier (Example 7) according to the present invention is used, and the dotted line is the case where the developer having the conventional toner carrier (Comparative Example 1) is used. The characteristics of

  As can be seen with reference to FIG. 5, the charge amount change rate when the number of printed sheets reaches 200,000 is 15 when the developer having the toner carrier (Example 7) according to the present invention is used. %, Whereas when a developer having a conventional toner carrier (Comparative Example 1) is used, it is 43%. The toner carrier according to the present invention (Example 7) had a change rate of about 1/3 with respect to the conventional toner carrier (Comparative Example 1). This means that the initial printing state can be maintained for a long time.

  Accordingly, in the present invention, it is possible to provide a toner carrier that can reduce the replacement frequency of the toner carrier or the developer and can extend the life, or a developer having the toner carrier. In the above description, the toner carrier of Example 7 has been described as an example of the toner carrier according to the present invention. However, the toner carrier to which the present invention is applied can achieve the same effect as described above. It is possible to provide a toner carrier that can reduce the frequency of replacement of the developer and extend the life of the developer, or a developer having the toner carrier.

(Embodiment 5)
In the fifth embodiment, an image forming apparatus that forms an image using the developer according to the present invention will be described. The configuration of an image forming apparatus, for example, a color image forming apparatus will be described with reference to FIG. FIG. 6 is a main configuration diagram showing an example of the configuration of the color image forming apparatus.

  In FIG. 6, 1y, 1m, 1c, and 1k are charging means, 2y, 2m, 2c, and 2k are exposure means, 3y, 3m, 3c, and 3k are developing hand images, and 4 is an image forming photosensitive drum (image carrier). 5 is an intermediate transfer medium, 6 is a final transfer roller, 7 is a final transfer output medium, and 8 is a cleaning means.

  In this color image forming apparatus, although not shown in FIG. 6, a developer cartridge for replenishment to each of the developing means 3y, 3m, 3c and 3k and a developer replenishment to each of the developing means are provided. And fixing means for fixing the developed image transferred onto the final transfer output medium 7 such as recording paper. The charging units 1y, 1m, 1c, and 1k, the exposure units 2y, 2m, 2c, and 2k, the developing units 3y, 3m, 3c, and 3k, and the image forming photosensitive drum 4 are disposed.

  In each of the developing units 3y, 3m, 3c, and 3k, a two-component developer containing a non-magnetic powder toner and a magnetic carrier having different colors is incorporated. That is, each of these developing means incorporates the two-component developer containing the toner carrier and the toner described in any of the first to third embodiments. Here, for example, a toner carrier having the characteristics shown in Table 5 is used as the toner carrier.

  The developing sleeves 31y, 31m, 31c, and 31k existing in the developing units 3y, 3m, 3c, and 3k are used to form an image of each color developer contained in the developing units 3y, 3m, 3c, and 3k. The non-magnetic powder toner contained in the two-component developer is transported to the opposite surface of the photoconductive drum 4 and the electrostatic latent image formed on the image forming photoconductive drum 4 is transferred to the image forming photoconductive drum 4. Has the role of flying up.

  In this embodiment, the developing means 3y has a yellow (y) developer, the developing means 3m has a magenta (m) developer, and the developing means 3c has a cyan (c) developer. 3k contains a black (k) developer.

  Further, in this embodiment, the same alphabetic suffixes attached to the respective reference numerals attached to the charging means, the exposure means, and the developing means are combined to form a developed image of each color. ing. That is, first, the surface of the image-forming photosensitive drum 4 is charged to a predetermined surface potential by the charging unit 1y, then an electrostatic latent image is formed by the exposure unit 2y, and further, the image unit is formed by the developing unit 3y. The non-magnetic powder toner contained in the two-component developer is attached to the electrostatic latent image formed on the photosensitive photosensitive drum 4 to form a yellow developed image.

  Next, the surface of the image-forming photosensitive drum 4 is charged to a predetermined surface potential from above the yellow developed image previously formed on the image-forming photosensitive drum 4 by the charging means 1m, and then the exposure means 2m. Then, an electrostatic latent image is formed by the developing unit 3m, and the nonmagnetic powder toner contained in the two-component developer is attached to the electrostatic latent image formed on the image-forming photosensitive drum 4 by the developing unit 3m. Then, a magenta developed image is formed on the previously formed yellow developed image.

  Thereafter, image forming photosensitivity is performed by charging means 1c, exposure means 2c and developing means 3c for cyan, and charging means 1k, exposure means 2k and developing means 3k for black, as in the case of yellow and magenta. Each developed image is formed on the developed image formed on the body drum 4. The development image forming method as described above is called a so-called multiple development system. This is a color image forming method in which images of respective colors are sequentially superimposed.

  In the present embodiment, any type of two-component developer for electrophotography, a multi-function machine, a copier, a fax machine, etc. using the same can be obtained by adjusting the magnetic characteristics and charging characteristics of the carrier. The present invention can also be applied to an image forming apparatus, and the life of the two-component developer for electrophotography or the current organ can be extended as compared with the conventional case.

  As described above, according to the first to fifth embodiments, the following effects (1) to (5) are obtained.

  (1) Compared with the conventional case, the tin organic compound, which is a regulated substance, is not used as a curing agent, and the crosslinkability of the silicone resin is improved while maintaining the adhesion to the toner carrier core, and the charging characteristics, development It is possible to provide a resin-coated toner carrier for electrophotography having improved characteristics and life characteristics.

  (2) Compared with the conventional case, the tin organic compound, which is a regulated substance, is not used as a curing agent, and the crosslinkability of the silicone resin is improved (three-dimensional crosslinking) while maintaining adhesion to the toner carrier core. In addition, a resin-coated toner carrier for electrophotography having improved charging characteristics, development characteristics, and life characteristics can be provided.

  (3) Compared to the conventional case, the tin organic compound, which is a regulated substance, is not used as a curing agent, and the crosslinkability of the silicone resin is further improved while maintaining the adhesion to the toner carrier core (three-dimensional crosslinking) The resin-coated toner carrier for electrophotography having improved charging characteristics, development characteristics, and life characteristics can be provided.

  (4) A two-component developer for electrophotography that uses a resin-coated toner carrier for electrophotography with improved charging characteristics, development characteristics, and life characteristics as compared with conventional ones, and reduces the frequency of carrier or developer replacement. Can provide.

  (5) Compared with conventional ones, by using a two-component developer for electrophotography using a resin-coated toner carrier for electrophotography with improved charging characteristics, development characteristics, and life characteristics, high image quality, high speed, It is possible to provide an image forming apparatus capable of extending the service life, and for the end user, the replacement frequency of the developer can be reduced, and the cost of maintenance service and the like related to the developer can be suppressed.

  As described above, the resin-coated toner carrier for electrophotography according to the present invention can be applied to any type of two-component developer for electrophotography and image forming apparatuses such as multi-function machines, copiers, and fax machines using the same. Useful.

Sectional drawing which shows an example of the structure of the toner carrier of this invention Electron micrograph showing an example of the shape of the toner carrier core (one piece) before coating. Electron micrograph showing an example of toner carrier (one piece) shape after coating Electron micrograph showing an example of toner carrier (whole) shape after coating The figure which shows the relationship between the number of printed sheets and a charge amount change rate when using a developer using a toner carrier and a conventional developer, respectively. Main configuration diagram showing an example of the configuration of a color image forming apparatus

Explanation of symbols

1y, 1m, 1c, 1k Charging means 2y, 2m, 2c, 2k Exposure means 3y, 3m, 3c, 3k Developing means 4 Image forming photosensitive drum 5 Intermediate transfer medium 6 Final transfer roller 7 Final transfer output medium 8 Cleaning means 100 Toner carrier particles 110 Toner carrier core 120 Silicone resin coating layer

Claims (6)

Silicone resin (A) soluble in an organic solvent compatible with water and an organic solvent compatible with water by producing carrier core particles having an aggregated particle structure by sintering an oxide magnetic material And an amino-based silane coupling agent (B), an epoxy-based silane coupling agent (C), and water (D) are dissolved to prepare a coating resin solution, and the carrier core particles are used as the coating resin solution. Forming a coated resin layer by coating with
A method for producing a resin-coated toner carrier for electrophotography. The amino-based silane coupling agent (B) and the epoxy-based silane coupling agent (B) have three hydrolyzable groups,
The method for producing a resin-coated toner carrier for electrophotography according to claim 1. The range of the weight ratio (C / B) between the amino silane coupling agent (B) and the epoxy silane coupling agent (C) is 1 to 3,
The resin-coated toner carrier for electrophotography according to claim 1 or 2, wherein A resin-coated toner carrier for electrophotography, which is produced by the production method according to claim 1. A developer comprising the resin-coated toner carrier for electrophotography according to claim 4. An image forming apparatus that forms an image using the developer according to claim 5.