WO2011158589A1 - 電子写真現像剤用キャリア芯材、電子写真現像剤用キャリア、電子写真現像剤、および電子写真現像剤用キャリア芯材の製造方法 - Google Patents
電子写真現像剤用キャリア芯材、電子写真現像剤用キャリア、電子写真現像剤、および電子写真現像剤用キャリア芯材の製造方法 Download PDFInfo
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- WO2011158589A1 WO2011158589A1 PCT/JP2011/061332 JP2011061332W WO2011158589A1 WO 2011158589 A1 WO2011158589 A1 WO 2011158589A1 JP 2011061332 W JP2011061332 W JP 2011061332W WO 2011158589 A1 WO2011158589 A1 WO 2011158589A1
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- core material
- electrophotographic developer
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- carrier core
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G9/00—Developers
- G03G9/08—Developers with toner particles
- G03G9/10—Developers with toner particles characterised by carrier particles
- G03G9/113—Developers with toner particles characterised by carrier particles having coatings applied thereto
- G03G9/1132—Macromolecular components of coatings
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G9/00—Developers
- G03G9/08—Developers with toner particles
- G03G9/10—Developers with toner particles characterised by carrier particles
- G03G9/107—Developers with toner particles characterised by carrier particles having magnetic components
- G03G9/1087—Specified elemental magnetic metal or alloy, e.g. alnico comprising iron, nickel, cobalt, and aluminum, or permalloy comprising iron and nickel
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G9/00—Developers
- G03G9/08—Developers with toner particles
- G03G9/10—Developers with toner particles characterised by carrier particles
- G03G9/107—Developers with toner particles characterised by carrier particles having magnetic components
- G03G9/1075—Structural characteristics of the carrier particles, e.g. shape or crystallographic structure
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G9/00—Developers
- G03G9/08—Developers with toner particles
- G03G9/10—Developers with toner particles characterised by carrier particles
- G03G9/107—Developers with toner particles characterised by carrier particles having magnetic components
- G03G9/108—Ferrite carrier, e.g. magnetite
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G9/00—Developers
- G03G9/08—Developers with toner particles
- G03G9/10—Developers with toner particles characterised by carrier particles
- G03G9/113—Developers with toner particles characterised by carrier particles having coatings applied thereto
Definitions
- the present invention relates to a carrier core material for an electrophotographic developer (hereinafter sometimes simply referred to as “carrier core material”), a carrier for an electrophotographic developer (hereinafter sometimes simply referred to as “carrier”), and an electrophotographic developer. (Hereinafter, also simply referred to as “developer”), and a method for producing a carrier core material for an electrophotographic developer, and in particular, an electrophotographic developer used in a copying machine, an MFP (Multifunctional Printer), and the like.
- the present invention relates to a carrier core material for an electrophotographic developer provided, a carrier for an electrophotographic developer provided in an electrophotographic developer, an electrophotographic developer, and a method for producing such a carrier core material for an electrophotographic developer.
- a one-component developer using only toner as a component of developer and a two-component developer using toner and carrier as components of developer are provided. is there.
- toner charged to a predetermined charge amount is supplied to the photoreceptor.
- the electrostatic latent image formed on the photosensitive member is visualized with toner and transferred to a sheet.
- the visible image with toner is fixed on the paper to obtain a desired image.
- the developing device includes a rotatable magnet roller in which a plurality of S poles and N poles are alternately provided in the circumferential direction, and a stirring roller that stirs and mixes the toner and the carrier in the developing device.
- a carrier made of magnetic powder is carried by a magnet roller.
- a linear magnetic brush made of carrier particles is formed by the magnetic force of the magnet roller.
- a plurality of toner particles adhere to the surface of the carrier particles by frictional charging by stirring. Toner is supplied to the surface of the photoconductor by rotating the magnet roller so that the magnetic brush is applied to the photoconductor. In a two-component developer, development is performed in this way.
- the toner in the developing device is sequentially consumed by fixing to the paper, so new toner corresponding to the consumed amount is supplied from time to time to the developing device from the toner hopper attached to the developing device.
- the carrier is not consumed by development and is used as it is until the end of its life.
- the carrier which is a constituent material of the two-component developer includes a toner charging function and an insulating property for efficiently charging the toner by frictional charging by stirring, a toner transporting ability to appropriately transport and supply the toner to the photoreceptor, etc. Various functions are required.
- the above-described carrier is composed of a core material, that is, a carrier core material constituting a core portion, and a coating resin provided so as to cover the surface of the carrier core material.
- the carrier core material is desired to have good magnetic properties.
- the carrier is carried on the magnet roller by magnetic force in the developing device.
- the magnetism of the carrier core material itself specifically, the magnetization of the carrier core material itself is low, the holding force on the magnet roller is weakened, which may cause problems such as so-called carrier scattering.
- the particle size of toner particles in order to meet the demand for higher image quality of formed images, there is a tendency to reduce the particle size of toner particles, and accordingly, the particle size of carrier particles also tends to be reduced. If the carrier particle size is reduced, the carrier force of each carrier particle may be reduced. Therefore, a more effective countermeasure against the above-described carrier scattering problem is desired.
- Patent Document 1 Japanese Patent Application Laid-Open No. 2008-241742
- the carrier core material has good electrical characteristics, for example, the carrier core material itself has a high charge amount and has a high dielectric breakdown voltage, and from the viewpoints described above, the carrier core material itself It is desirable to have an appropriate resistance value. Specifically, for example, by having a high insulating property, even if a part of the carrier coating resin is peeled off due to long-term use, image defects due to charge leakage are prevented and the life of the carrier is extended. Can do. Further, since the carrier core material has an appropriate resistance value, image defects such as a decrease in image density due to the high resistance of the carrier can be prevented. Specifically, the resistance value is preferably in the range of 1 ⁇ 10 4 to 1 ⁇ 10 11 ⁇ ⁇ cm.
- a copying machine is generally installed and used in an office of an office or the like.
- a high temperature environment of about 30 ° C. when used in a high humidity environment of about 90% relative humidity, and conversely, when used at a low temperature of about 10 ° C. Or, it may be used in a low humidity environment with a relative humidity of about 35%.
- the temperature and relative humidity change it is desirable to reduce the change in the characteristics of the developer in the developing device provided in the copying machine, and the carrier core material constituting the carrier also
- the environment changes it is required that the characteristic change is small, that is, the so-called environment dependency is small.
- the inventors of the present application have conducted intensive studies on the cause of fluctuations in carrier physical properties, specifically, the charge amount and the resistance value, depending on the environment used. As a result, it was found that changes in physical properties of the carrier core material greatly affect the physical properties of the coated carrier. For this reason, it has been found that the conventional carrier core material represented by Patent Document 1 is insufficient with respect to the environmental dependency described above. For example, specifically, in an environment with a relatively high relative humidity, the above-described resistance value may be significantly lower than a resistance value in an environment with a relatively low relative humidity. Such a carrier core material is greatly affected by environmental changes and may affect image quality.
- the inventors of the present invention firstly set iron as a main component of the core composition in order to ensure good magnetic characteristics as basic characteristics. Thought. And while trying to optimize the resistance value, intensive studies were conducted on additives that do not impair the magnetic properties. As a result, it was found that a small amount of Na (sodium) has an effect of suppressing an increase in resistance value. Furthermore, it was found that when the amount of Na added is within a predetermined range, both high magnetization and high insulation can be achieved.
- Na added excessively out of the added Na had an adverse effect on environmental dependence.
- Na located in the surface layer portion of the carrier core material adsorbs moisture present in a relatively large amount in a high relative humidity environment to promote charge leakage, and as a result, It was considered that the resistance value was lowered and the environmental difference was increased under the environment of high relative humidity. Therefore, in order to reduce the influence on the environmental dependency considered to be caused by Na and to make the resistance value within an appropriate range, the range of the Na content as a component of the carrier core material is defined. With such a mechanism, it is considered that the resistance value can be optimized and the environment dependency can be improved.
- the carrier core material for an electrophotographic developer according to the present invention has a core composition represented by the general formula: Fe 3 O 4 as a main component, and contains Na of 30 ppm (parts per million) or more and 400 ppm or less.
- the Na content in the carrier core material it is preferable to set the Na content in the carrier core material to 30 ppm or more because the resistance value can be optimized and the decrease in image density due to high resistance can be suppressed. Further, it is preferable to set the Na content in the carrier core material to 400 ppm or less because an increase in environmental fluctuation due to excessive Na can be suppressed.
- the resistance value can be optimized while reducing the environmental dependency of the carrier core material itself.
- the carrier core material has a core composition represented by Fe 3 O 4 as a main component, a trace amount of Fe 2 O 3 is also included.
- the Na content of the carrier core material was analyzed by the following method.
- the carrier core material according to the present invention was dissolved in an acid solution, and quantitative analysis was performed by ICP.
- ICP analysis ICPS-7510 manufactured by Shimadzu Corporation was used, and for the ICP measurement, a calibration curve method was used. Note that the wavelength of Na was 5859.592 nm.
- the Na content of the carrier core material described in the present invention is the amount of Na obtained by this quantitative analysis by ICP.
- Na may be mixed in a beaker or process, and the analysis result may fluctuate. Therefore, it shall be performed on the conditions which do not mix.
- the analysis may be performed by using an analysis method in which Na is not mixed as much as possible.
- the Na content is preferably 50 ppm or more and 200 ppm or less.
- an electrophotographic developer carrier is an electrophotographic developer carrier used for an electrophotographic developer, and has a core composition represented by a general formula: Fe 3 O 4.
- a carrier core material for an electrophotographic developer that has Na as a main component and contains Na of 30 ppm to 400 ppm and a resin that covers the surface of the carrier core material for an electrophotographic developer.
- Such a carrier for an electrophotographic developer includes the carrier core material for an electrophotographic developer having the above-described configuration, the electrical characteristics are good and the environment dependency is small.
- an electrophotographic developer is an electrophotographic developer used for electrophotographic development, and has a core composition represented by a general formula: Fe 3 O 4 as a main component.
- electrophotographic developer includes the electrophotographic developer carrier having the above-described configuration, it is possible to form an image with good image quality even in various environments.
- a method for producing a carrier core material for an electrophotographic developer is a method for producing a carrier core material for an electrophotographic developer containing iron, oxygen and sodium as a core composition, A raw material containing iron and a raw material containing sodium are mixed to granulate so that the Na content in the granulated powder is 100 to 1000 ppm, and the powdered material granulated by the granulating step is fired Firing step.
- the carrier core material for an electrophotographic developer having the above-described configuration can be efficiently produced.
- the firing step may include a cooling step of cooling in an atmosphere having an oxygen concentration of 0.001% or more. By doing so, the environment dependency can be further reduced.
- the carrier core material for an electrophotographic developer according to the present invention has good electrical characteristics of the carrier core material itself and is less dependent on the environment.
- the carrier for an electrophotographic developer according to the present invention has good electrical characteristics and low environmental dependency.
- the electrophotographic developer according to the present invention can form an image with good image quality even in various environments.
- the carrier core material for an electrophotographic developer having the above-described configuration can be efficiently produced.
- FIG. 1 is an electron micrograph showing the appearance of a carrier core material according to an embodiment of the present invention.
- the carrier core material 11 has a substantially spherical outer shape.
- the particle diameter of the carrier core material 11 according to an embodiment of the present invention is about 35 ⁇ m and has an appropriate particle size distribution.
- the above-mentioned particle diameter means a volume average particle diameter.
- the particle size and particle size distribution are arbitrarily set depending on required developer characteristics, yield in the manufacturing process, and the like.
- minute irregularities mainly formed in a baking process described later are formed on the surface of the carrier core material 11.
- the carrier according to one embodiment of the present invention has a substantially spherical outer shape, similar to the carrier core material 11.
- the carrier is obtained by thinly coating the surface of the carrier core material 11 with a resin, that is, the particle diameter is almost the same as that of the carrier core material 11. Unlike the carrier core material 11, the carrier surface is almost completely covered with a resin.
- the developer according to one embodiment of the present invention is composed of the above carrier and toner.
- the outer shape of the toner is also substantially spherical.
- the toner is mainly composed of a styrene acrylic resin or a polyester resin, and contains a predetermined amount of pigment, wax or the like.
- Such a toner is manufactured by, for example, a pulverization method or a polymerization method.
- a toner having a particle diameter of about 5 ⁇ m, which is about 1/7 of the particle diameter of the carrier is used.
- the mixing ratio of the toner and the carrier is also arbitrarily set according to the required developer characteristics and the like.
- Such a developer is produced by mixing a predetermined amount of carrier and toner with an appropriate mixer.
- FIG. 2 is a flowchart showing typical steps in the manufacturing method for manufacturing the carrier core material according to the embodiment of the present invention.
- a method for manufacturing a carrier core material according to an embodiment of the present invention will be described with reference to FIG.
- a raw material containing sodium (Na) and a raw material containing iron are prepared. And the prepared raw material is mix
- an appropriate blending ratio is a blending ratio such that the finally obtained carrier core material contains 30 ppm to 400 ppm of Na. Since Na evaporates during calcination, main calcination, or oxidation treatment, the blending ratio is set in anticipation of evaporation. Specifically, for example, in a granulation step described later, a raw material containing iron and a raw material containing sodium are mixed so that the Na content in the granulated powder becomes 100 to 1000 ppm.
- Na is contained in iron oxide or other raw materials, but the Na content in the raw materials is almost evaporated in firing or other steps. Therefore, the present invention is outside the range of inevitable impurities. That is, the Na content contained in the carrier core material manufactured in a system in which no Na-containing raw material is mixed is inevitably smaller than the Na content defined in the present invention.
- the iron raw material which comprises the carrier core material which concerns on one Embodiment of this invention what is necessary is just metallic iron or its oxide.
- Fe 2 O 3 , Fe 3 O 4 , Fe, and the like that exist stably at normal temperature and pressure are preferably used.
- sodium raw material, NaOH and NaCl which exist stably under normal temperature normal pressure are used suitably.
- a small amount of Si such as SiO 2 may be added to the carrier core material.
- SiO 2 raw material to be added amorphous silica, crystalline silica, colloidal silica or the like is preferably used.
- the mixed raw material is slurried (FIG. 2 (B)). That is, these raw materials are weighed according to the target composition of the carrier core material and mixed to obtain a slurry raw material.
- a reducing agent may be further added to the slurry raw material described above in order to advance the reduction reaction in a part of the baking process described later.
- the reducing agent carbon powder, polycarboxylic acid organic substances, polyacrylic acid organic substances, maleic acid, acetic acid, polyvinyl alcohol (PVA (polyvinyl alcohol)) organic substances, and mixtures thereof are preferably used.
- the water is added to the slurry raw material described above and mixed and stirred, so that the solid content concentration is 40 wt% or more, preferably 50 wt% or more. If the solid content concentration of the slurry raw material is 50% by weight or more, it is preferable because the strength of the granulated pellet can be maintained.
- the slurryed raw material is granulated (FIG. 2 (C)).
- Granulation of the slurry obtained by mixing and stirring is performed using a spray dryer.
- the atmospheric temperature during spray drying may be about 100 to 300 ° C. Thereby, a granulated powder having a particle diameter of 10 to 200 ⁇ m can be obtained.
- the obtained granulated powder is preferably adjusted for particle size at this point in consideration of the final particle size of the product by removing coarse particles and fine powder using a vibration sieve or the like.
- baking is performed about the granulated material (FIG.2 (D)).
- the obtained granulated powder is put into a furnace heated to about 900 to 1500 ° C. to raise the temperature, and as a sintering reaction step, maintained for 1 to 24 hours for sintering. React to produce the desired fired product.
- the fired product is cooled to about room temperature as a cooling step.
- firing is performed including three steps. That is, in the firing step, the powdered material granulated in the granulation step is heated to a predetermined temperature at which sintering is possible, and after the temperature rising step, the powdered material is heated at a predetermined temperature at which sintering is possible.
- the oxygen concentration in the firing furnace may be any condition as long as the ferritization reaction proceeds. Specifically, at 1200 ° C., the oxygen concentration of the introduced gas is set to be 10 ⁇ 7 % or more and 3% or less. Adjust and fire under flow conditions.
- an oxygen meter zirconia type O 2 sensor TB-IIF + control unit manufactured by Dai-ichi Thermal Research Co., Ltd. was used.
- the reducing atmosphere necessary for ferritization may be controlled by adjusting the reducing agent.
- a temperature of 900 ° C. or higher is preferable.
- the firing temperature is 1500 ° C. or lower, the particles are not excessively sintered, and a fired product can be obtained in the form of powder.
- the oxygen concentration during cooling in the firing step is set to a predetermined amount or more. That is, in the firing step, when cooling to about room temperature, the cooling may be performed in an atmosphere in which the oxygen concentration is a predetermined concentration, specifically 0.001% or more. More specifically, the oxygen concentration of the introduced gas introduced into the electric furnace is 0.001% or more, preferably 0.001% or more and 1% or less.
- the oxygen amount in a ferrite can exist excessively in the inner layer of a carrier core material. Then, the oxygen content in the inner layer can be relatively increased, and a decrease in resistance value at high temperature and high humidity due to the influence of charge leakage or the like can be suppressed. Therefore, here, cooling is performed in an environment of the above oxygen concentration.
- the fired product is coarsely pulverized with a hammer mill or the like. That is, pulverization is performed on the baked granular material (FIG. 2E). After that, classification is performed using a vibrating screen. That is, classification is performed on the pulverized granular material (FIG. 2 (F)).
- grains of the carrier core material with a desired particle size can be obtained.
- the classified granular material is oxidized (FIG. 2 (G)). That is, the particle surface of the carrier core material obtained at this stage is heat-treated (oxidation treatment).
- the target carrier core material is obtained by holding at 200 to 700 ° C. for 0.1 to 24 hours in an atmosphere having an oxygen concentration of 10 to 100%. More preferably, it is 0.5 to 20 hours at 250 to 600 ° C., and more preferably 1 to 12 hours at 300 to 550 ° C.
- the carrier core material according to one embodiment of the present invention is manufactured. In addition, about such an oxidation treatment process, it is arbitrarily performed as needed.
- the method for producing a carrier core material for an electrophotographic developer according to the present invention is a method for producing a carrier core material for an electrophotographic developer containing iron, oxygen and sodium as a core composition, wherein the raw material containing iron and sodium A granulation step of mixing raw materials containing slag and granulating so that the Na content in the granulated powder is 100 to 1000 ppm, and a firing step of firing the powdered material granulated by the granulation step .
- the carrier core material for an electrophotographic developer having the above-described configuration can be efficiently produced.
- the firing step includes a cooling step of cooling in an atmosphere in which the oxygen concentration is 0.001% or more, the environmental dependency can be further reduced.
- the carrier core material obtained in this way is coated with a resin (FIG. 2 (H)).
- the obtained carrier core material according to the present invention is covered with a silicone resin, an acrylic resin, or the like.
- an electrophotographic developer carrier according to an embodiment of the present invention is obtained.
- a coating method such as silicone resin or acrylic resin can be performed by a known method. That is, the carrier for an electrophotographic developer according to the present invention is a carrier for an electrophotographic developer used for an electrophotographic developer, and has a core composition represented by the general formula: Fe 3 O 4 as a main component. And a carrier core material for an electrophotographic developer containing Na in a range of 30 ppm to 400 ppm, and a resin that covers the surface of the carrier core material for an electrophotographic developer.
- Such a carrier for an electrophotographic developer includes the carrier core material for an electrophotographic developer having the above-described configuration, the electrical characteristics are good and the environment dependency is small.
- the carrier and toner thus obtained are mixed in predetermined amounts (FIG. 2 (I)).
- the carrier for an electrophotographic developer according to one embodiment of the present invention obtained by the above-described manufacturing method is mixed with an appropriate known toner.
- the electrophotographic developer according to one embodiment of the present invention can be obtained.
- an arbitrary mixer such as a V-type mixer is used. That is, the electrophotographic developer according to the present invention is an electrophotographic developer used for electrophotographic development, having a core composition represented by the general formula: Fe 3 O 4 as a main component, and Na of 30 ppm.
- an electrophotographic developer carrier core material containing 400 ppm or less By triboelectric charging between an electrophotographic developer carrier core material containing 400 ppm or less, and an electrophotographic developer carrier comprising a resin that covers the surface of the electrophotographic developer carrier core material, and the electrophotographic developer carrier And a toner capable of being charged in electrophotography.
- electrophotographic developer includes the electrophotographic developer carrier having the above-described configuration, it is possible to form an image with good image quality even in various environments.
- Example 1 15 kg of Fe 2 O 3 (average particle size: 0.6 ⁇ m) is dispersed in 3.8 kg of water, 150 g of an ammonium polycarboxylate dispersant as a dispersant, 170 g of carbon black as a reducing agent, and colloidal as a SiO 2 raw material 398 g of silica (solid concentration 50%) and 3 g of NaOH were added to form a mixture. As a result of measuring the solid content concentration at this time, it was 75% by weight. This mixture was pulverized by a wet ball mill (media diameter ⁇ 2 mm) to obtain a mixed slurry.
- the slurry was sprayed into hot air at about 130 ° C. with a spray dryer to obtain dry granulated powder. At this time, granulated powder other than the target particle size distribution was removed by sieving. This granulated powder was put into an electric furnace and fired at 1075 ° C. for 3 hours. At this time, the inside of the electric furnace was flowed to an electric furnace whose atmosphere was adjusted so that the oxygen concentration was 0.03%, and the oxygen concentration during cooling was also 0.03%. The obtained fired product was classified using a sieve after pulverization to give a volume average particle size of 35 ⁇ m. Furthermore, the obtained carrier core material was oxidized at 550 ° C. for 1 hour in the atmosphere to obtain a carrier core material according to Example 1. Table 1 shows the material properties, magnetic properties, and electrical properties of the obtained carrier core material. In addition, the core material composition described in Table 1 is a result obtained by measuring the obtained carrier core material by the analysis method described above. The same applies to the second and subsequent embodiments.
- Example 2 A carrier core material according to Example 2 was obtained in the same manner as in Example 1, except that 8 g of NaOH was added. Table 1 shows the material properties, magnetic properties, and electrical properties of the obtained carrier core material.
- Example 3 A carrier core material according to Example 3 was obtained in the same manner as in Example 1, except that 18 g of NaOH was added. Table 1 shows the material properties, magnetic properties, and electrical properties of the obtained carrier core material.
- Example 4 A carrier core material according to Example 4 was obtained in the same manner as in Example 1 except that 30 g of NaOH was added. Table 1 shows the material properties, magnetic properties, and electrical properties of the obtained carrier core material.
- Comparative Example 1 A carrier core material according to Comparative Example 1 was obtained in the same manner as in Example 1 except that the amount of NaOH added was 0.5 g. Table 1 shows the material properties, magnetic properties, and electrical properties of the obtained carrier core material.
- Comparative Example 2 A carrier core material according to Comparative Example 2 was obtained in the same manner as in Example 1 except that 35 g of NaOH was added. Table 1 shows the material properties, magnetic properties, and electrical properties of the obtained carrier core material.
- the oxidation temperature under the oxidation treatment conditions is the temperature (° C.) in the above-described oxidation step, and all are 550 ° C. Further, the oxidation time is 2 hours in all cases.
- the measurement of the Na content is as described above.
- B. in Table 1 D. Indicates a state of dielectric breakdown (Break Down).
- the carrier core material was conditioned for one day in an environment of 10 ° C. and a relative humidity of 35% (under an LL environment) and an environment of 30 ° C. and a relative humidity of 90% (under an HH environment). I did it.
- two 2 mm thick SUS (JIS) 304 plates whose surfaces were electrolytically polished as electrodes on an insulating plate placed horizontally, such as an acrylic plate coated with Teflon (registered trademark), were placed between the electrodes. It arrange
- a magnet having a cross-sectional area of 240 mm 2 is arranged behind each electrode plate to form a bridge of the powder to be measured between the electrodes. .
- each voltage is applied between the electrodes in order from a small one, and a current value flowing through the powder to be measured is measured by a two-terminal method to calculate an electric resistance value.
- a super insulation meter SM-8215 manufactured by Hioki Electric Co., Ltd. is used.
- surface was measured.
- Various magnets can be used as long as the powder can form a bridge.
- a permanent magnet having a surface magnetic flux density of 1000 gauss or more, for example, a ferrite magnet is used. .
- the environmental difference in resistance value is obtained by subtracting the resistance value in a high temperature and high humidity environment from the resistance value in a low temperature and low humidity environment when 100 V is applied.
- ⁇ 1000 is the magnetization when the external magnetic field is 1000 Oe.
- FIG. 3 is a graph showing the relationship between the resistance value and the applied voltage when the Na content is changed in Examples 1 to 4, Comparative Example 1, and Comparative Example 2 described above.
- the vertical axis indicates the resistance value ( ⁇ ⁇ cm), and the horizontal axis indicates the applied voltage (V).
- the resistance value is higher than 1.0E ⁇ 11 ⁇ ⁇ cm at an applied voltage of 750 V or less.
- the resistance value is lower than 1.0E ⁇ 11 ⁇ ⁇ cm at any applied voltage. That is, it is 1 ⁇ 10 11 ⁇ ⁇ cm or less.
- the carrier core materials in Examples 1 to 4 achieve a proper resistance value as compared with the carrier core material shown in Comparative Example 1. This is because, when the content of Na in the inner layer contained in a trace amount in the Fe 3 O 4 of the crystal as the main component of the carrier core material increases proportionately, a small amount of charge leakage occurs, resulting in a resistance value. Is considered to be slightly reduced.
- the environmental differences of the resistance values are 1.3 in Comparative Example 1 and 1.5 in Comparative Example 2, whereas in Examples 1 to 4, all are 1.2 or less. . That is, in Examples 1 to 4, the environmental difference in resistance value is small, and the environmental dependency is small.
- the magnetization is 50 emu / g or more in each of Examples 1 to 4, which is a level with no problem under actual use conditions.
- the carrier core material for an electrophotographic developer according to the present invention has the above-described configuration, the carrier core material itself has good electrical characteristics and is less dependent on the environment.
- the environmental difference is 0.8, which is at least 1 or less. Therefore, in order to further reduce the environmental dependency, the Na content is preferably set to 50 ppm or more and 200 ppm or less.
- Such carrier core materials can be applied even when higher magnetization is required because the magnetization ( ⁇ 1000 ) is 60 emu / g or more.
- Na is added as NaOH or NaCl.
- the present invention is not limited to this, and other forms such as NaHCO 3 may be added.
- the step of proceeding the sintering reaction which is a step before cooling, it may be performed in the same atmosphere as the cooling step.
- the firing step includes a cooling step of cooling in an atmosphere in which the oxygen concentration is 0.001% or more. However, if the required environmental dependency is sufficient, this step may be omitted. Good. That is, cooling may be performed in a state where the oxygen concentration is less than 0.001%.
- the carrier core material for electrophotographic developer, the carrier for electrophotographic developer, the electrophotographic developer, and the method for producing the carrier core material for electrophotographic developer according to the present invention can be used in various environments. It is used effectively when applied to.
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Abstract
Description
Fe2O3(平均粒径:0.6μm)15kgを水3.8kg中に分散し、分散剤としてポリカルボン酸アンモニウム系分散剤を150g、還元剤としてカーボンブラックを170g、SiO2原料としてコロイダルシリカ(固形分濃度50%)を398g、NaOHを3g添加して混合物とした。このときの固形分濃度を測定した結果、75重量%であった。この混合物を湿式ボールミル(メディア径φ2mm)により粉砕処理し、混合スラリーを得た。
添加するNaOHを8gとした以外は、実施例1と同様の方法で、実施例2に係るキャリア芯材を得た。得られたキャリア芯材の物質的特性、磁気的特性および電気的特性を表1に示す。
添加するNaOHを18gとした以外は、実施例1と同様の方法で、実施例3に係るキャリア芯材を得た。得られたキャリア芯材の物質的特性、磁気的特性および電気的特性を表1に示す。
添加するNaOHを30gとした以外は、実施例1と同様の方法で、実施例4に係るキャリア芯材を得た。得られたキャリア芯材の物質的特性、磁気的特性および電気的特性を表1に示す。
添加するNaOHを0.5gとした以外は、実施例1と同様の方法で、比較例1に係るキャリア芯材を得た。得られたキャリア芯材の物質的特性、磁気的特性および電気的特性を表1に示す。
添加するNaOHを35gとした以外は、実施例1と同様の方法で、比較例2に係るキャリア芯材を得た。得られたキャリア芯材の物質的特性、磁気的特性および電気的特性を表1に示す。
Claims (6)
- 一般式:Fe3O4で表されるコア組成を主成分として有し、
Naを30ppm以上400ppm以下含有する、電子写真現像剤用キャリア芯材。 - Naの含有量が、50ppm以上200ppm以下である、請求項1に記載の電子写真現像剤用キャリア芯材。
- 電子写真の現像剤に用いられる電子写真現像剤用キャリアであって、
一般式:Fe3O4で表されるコア組成を主成分として有し、Naを30ppm以上400ppm以下含有する電子写真現像剤用キャリア芯材と、
前記電子写真現像剤用キャリア芯材の表面を被覆する樹脂とを備える、電子写真現像剤用キャリア。 - 電子写真の現像に用いられる電子写真現像剤であって、
一般式:Fe3O4で表されるコア組成を主成分として有し、Naを30ppm以上400ppm以下含有する電子写真現像剤用キャリア芯材、および前記電子写真現像剤用キャリア芯材の表面を被覆する樹脂を備える電子写真現像剤用キャリアと、
前記電子写真現像剤用キャリアとの摩擦帯電により電子写真における帯電が可能なトナーとを備える、電子写真現像剤。 - 鉄、酸素およびナトリウムをコア組成として含む電子写真現像剤用キャリア芯材の製造方法であって、
鉄を含む原料とナトリウムを含む原料を混合して造粒粉中のNa含有量が100~1000ppmとなるように造粒を行う造粒工程と、
前記造粒工程により造粒した粉状物を焼成する焼成工程とを含む、電子写真現像剤用キャリア芯材の製造方法。 - 前記焼成工程は、酸素濃度を0.001%以上とした雰囲気下で冷却する冷却工程を含む、請求項5に記載の電子写真現像剤用キャリア芯材の製造方法。
Priority Applications (5)
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US13/704,016 US20130084521A1 (en) | 2010-06-14 | 2011-05-17 | Carrier core particles for electrophotographic developer, carrier for electrophotographic developer, electrophotographic developer and method for manufacturing the carrier core particles |
KR1020127032842A KR101291984B1 (ko) | 2010-06-14 | 2011-05-17 | 전자 사진 현상제용 캐리어 심재, 전자 사진 현상제용 캐리어, 전자 사진 현상제, 및 전자 사진 현상제용 캐리어 심재의 제조 방법 |
CN2011800289891A CN102939568A (zh) | 2010-06-14 | 2011-05-17 | 电子照相显影剂用载体芯材、电子照相显影剂用载体、电子照相显影剂以及电子照相显影剂用载体芯材的制备方法 |
EP11795497.4A EP2581791B1 (en) | 2010-06-14 | 2011-05-17 | Carrier core material for electrophotographic developer, carrier for electrophotographic developer, electrophotographic developer, and method for producing carrier core material for electrophotographic developer |
US14/175,276 US20140154623A1 (en) | 2010-06-14 | 2014-02-07 | Carrier core particles for electrophotographic developer, carrier for electrophotographic developer, electrophotographic developer and method for manufacturing the carrier core particles |
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JP2010135168A JP4938883B2 (ja) | 2010-06-14 | 2010-06-14 | 電子写真現像剤用キャリア芯材、電子写真現像剤用キャリア、電子写真現像剤、および電子写真現像剤用キャリア芯材の製造方法 |
JP2010-135168 | 2010-06-14 |
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US13/704,016 A-371-Of-International US20130084521A1 (en) | 2010-06-14 | 2011-05-17 | Carrier core particles for electrophotographic developer, carrier for electrophotographic developer, electrophotographic developer and method for manufacturing the carrier core particles |
US14/175,276 Continuation US20140154623A1 (en) | 2010-06-14 | 2014-02-07 | Carrier core particles for electrophotographic developer, carrier for electrophotographic developer, electrophotographic developer and method for manufacturing the carrier core particles |
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WO2011158589A1 true WO2011158589A1 (ja) | 2011-12-22 |
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US (2) | US20130084521A1 (ja) |
EP (1) | EP2581791B1 (ja) |
JP (1) | JP4938883B2 (ja) |
KR (1) | KR101291984B1 (ja) |
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JP2013205784A (ja) * | 2012-03-29 | 2013-10-07 | Dowa Electronics Materials Co Ltd | 電子写真現像剤用キャリア芯材の製造方法、電子写真現像剤用キャリア芯材、電子写真現像剤用キャリア、および電子写真現像剤 |
JP6145846B2 (ja) * | 2013-03-29 | 2017-06-14 | パウダーテック株式会社 | 電子写真現像剤用樹脂被覆キャリア及び該樹脂被覆キャリアを用いた電子写真現像剤 |
CN103309190B (zh) * | 2013-05-29 | 2015-06-03 | 湖北鼎龙化学股份有限公司 | 载体芯材及其制造方法、载体及静电荷图像显影剂 |
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CN102939568A (zh) | 2013-02-20 |
US20130084521A1 (en) | 2013-04-04 |
KR20130014064A (ko) | 2013-02-06 |
US20140154623A1 (en) | 2014-06-05 |
JP4938883B2 (ja) | 2012-05-23 |
KR101291984B1 (ko) | 2013-08-09 |
EP2581791A4 (en) | 2014-10-22 |
EP2581791B1 (en) | 2015-08-26 |
JP2012002868A (ja) | 2012-01-05 |
EP2581791A1 (en) | 2013-04-17 |
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