EP0086444A1 - Magnetic carrier powder for two-component toner - Google Patents
Magnetic carrier powder for two-component toner Download PDFInfo
- Publication number
- EP0086444A1 EP0086444A1 EP83101193A EP83101193A EP0086444A1 EP 0086444 A1 EP0086444 A1 EP 0086444A1 EP 83101193 A EP83101193 A EP 83101193A EP 83101193 A EP83101193 A EP 83101193A EP 0086444 A1 EP0086444 A1 EP 0086444A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- magnetic carrier
- ferrite
- particle size
- particles
- carrier powder
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- 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
- G03G9/1085—Ferrite carrier, e.g. magnetite with non-ferrous metal oxide, e.g. MgO-Fe2O3
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
- H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
- H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
- H01F1/34—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials non-metallic substances, e.g. ferrites
- H01F1/36—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials non-metallic substances, e.g. ferrites in the form of particles
-
- 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
Definitions
- the present invention relates to a magnetic carrier powder. More particularly, the present invention relates to a magnetic carrier powder to be used for magnetic brush development.
- a magnetic carrier powder to be used for magnetic brush development there has been used an iron powder or a soft ferrite powder and it has been believed that the average particle size of the powder should preferably be from 30 to 1000 ⁇ m.
- a magnetic carrier powder which is capable of providing an image having an improved image quality such as the resolving power, graininess, black uniformity or gradation.
- the present inventors have conducted extensive researches and as a result, have found that the object can be attained by reducing the ferrite powder particlas to have an average particle size smaller than that of the conventional ferrite particles.
- the present invention has . been accomplished based on this discovery.
- the present invention provides a magnetic carrier powder composed of ferrite powder particles having a spinel structure and an average particle size of less than 30 ⁇ m.
- the magnetic carrier powder of the present invention is made of a ferrite having a spinel structure.
- the ferrite having a spinel structure there may be mentioned a so-called soft ferrite such as a 2-3 spinel or a 1-3 spinel, a magnetite (Fe 3 0 4 ) or a maghemite ( y -Fe 2 O 3 ).
- ferrites i) and ii) are particularly preferred in view of its magnetic characteristics.
- a spinel ferrite comprising at most 60 molar % of MO where M is Ni, Mn, Mg, Zn, Cu, Co or a combination thereof, as calculated as a divalent oxide, and at least 40 molar % of Fe 2 0 3 as calculated as a trivalent metal oxide.
- M is a combination of at least two kinds of metals
- their proportions may be optionally selected.
- ferrites i the following ferrites ia) and ib) are preferred.
- M is Ni, Mn, Mg, Cu, Zn or a combination thereof.
- M is a combination of at least two kinds of metals, . their proportions may be optionally selected.
- M is a combination of Ni, Mn, Mg, Cu, Zn or a combination thereof, with at most 20 atom % of Co.
- M is a combination of at least two kinds of metals selected from Ni, Mn, Mg, Cu and Zn, their proportions may be optionally selected.
- the saturation magnetization becomes extremely high, whereby the deposition of the carrier on the photosensitive material or scattering of the carrier from the magnetic brush can be minimized.
- the ferrite powder particles having the above-mentioned composition may further contain . at most 5 molar % of an oxide of Ca, Bi, Cr, Ta, Mo, Si, V, B, Pb, K, Na, or Ba.
- Such ferrite powder particles have an average particle size of less than 30 ⁇ m.
- the image quality particularly the resolving power, graininess, uniformity or gradation tends to be degraded. Further, the image quality tends to be of high contrast, which taxes the eyes of the observer.
- the average particle size should preferably be at least 5 ⁇ m. Particularly good results. are obtainable when the average particle size is from 5 to 25 ⁇ m.
- the particle size distribution is usually such that about 70% of the total particles have a particle size falling within the range of + 30% of the average particle size.
- Such ferrite particles are used as a carrier without being coated with a coating layer on the surfaces or without being dispersed in a resin. Therefore, the magnetic carrier powder of the present invention has great mechanical strength and hardly undergoes thermal degradation, whereby the degradation of its properties with time is minimum and its useful life is very long. Further, the reduction of the saturation magnetization due to the decrease of the volume occupying rate is minimum and its production is quite easy.
- the ferrite powder particles constituting the magnetic carrier powder of the present invention preferably have an electric resistance of from 10 4 to 10 14 ⁇ , more preferably from 10 5 to 10 12 n, when 100 V is applied in the following manner.
- the measurement of the electric resistance of the ferrite powder particles is conducted in the following manner in accordnace with a magnetic brush development system.
- An N-pole and a S-pole are arranged to face each other with a magnetic pole distance of 8 mm so that the surface magnetic flux density of the magnetic poles becomes 1500 Gauss and the surface area of the facing poles is 10 x 30 mm.
- a pair of flat non-magnetic electrodes are disposed in parallel to each other with an electrode distance of 8 mm.
- 200 mg of a test sample is placed and the sample is held between the electrodes by the magnetic force.
- the electric resistance is measured by an insulation resistance tester or an ampere meter.
- the image quality tends to be of high contrast.
- the saturation magnetization 0" m of the ferrite particles is preferably at least 35 emu/g, whereby the deposition of the carrier on the photosensitive material or the scattering of the carrier by repeated development operations can be minimized. In this case, better results are obtainable when the saturation magnetization ⁇ m is at least 40 emu/g.
- the magnetic carrier powder composed of such ferrite powder particles may be prepared in such a manner as disclosed in U. S. Patent No. 3,839,029, No. 3,914,181 or No. 3,926,657.
- the corresponding metal oxides are mixed.
- a solvent such as water is added and the mixture is slurried, for instance, in a ball mill.
- Other additives such as a dispersing agent and a binder may be added as the case requires.
- the slurry is granulated and dried by a spray drier.
- the granules thereby obtained are burned at a predetermined burning temperature in a predetermined burning atmosphere.
- the burning is conducted in a fluidized furnace, a rotary kiln or a tunnel furnace, whereby particles having the above-mentioned average particle size is efficiently produced.
- the particles are pulverized or dispersed to obtain a desired particles size, whereby the magnetic carrier powder of the present inention is obtained.
- the magnetic carrier powder of the present invention is mixed with a toner to obtain a developer.
- the type of the toner to be used is not critical and any toner may be used.
- the magnetic brush development system and the photosensitive material to be employed to obtain an electrostatic copy image are not critical and an electrostatic copy image can be obtained in accordance with a conventional magnetic brush development method.
- an extremely good image quality is obtainable. Namely, the resolving power, graininess, black uniformity and gradation thereby obtained are extremely good.
- the image is of soft gradation, which does not very much tax the eyes of the observer.
- composition of the ferrite powder particles or the conditions for the burning may readily be varied to optionally change the quantity of magnetism or electric resistance so that images having various image densities and gradations may readily be obtained.
- the ferrite powder particles do not have a coating layer or they are not incorporated in a resin. Therefore, the degradation of the characteristics is minimum even when they are used for a long period of time, and they have good durability and a long useful life. They are free from the reduction of the magnetic characteristics which is likely to be led when incorporated with a resin component. Further, the number of the steps for their production can be minimized and the production is easy, whereby the production costs will be low.
- Metal oxides were mixed at various ratios (calculated as a divalent metal oxide and Fe 2 0 3 ) as shown in Table 1. One part by weight of water was added to one part by weight of each mixture and mixed in a ball mill for five hours to obtain a slurry. Appropriate amounts of a dispersing agent and a binder were added.
- the slurry was granulated and dried at a temperature of at least 150°C by a spray drier.
- Each granular product was burned in a fluidized furnace at the maximum temperature as shown in Table 1 in the atmosphere also as shown in Table 1.
- A represents an air atmosphere
- N represents a nitrogen atmosphere.
- the average particle size is an average particle size of 5000 particles randomly selected under observation by an electron microscope.
- the average particle size of 20 ⁇ m indicates that the particles have a particle size within a range of from 5 to 30 ⁇ m
- the average particle size 40 11 m indicates that the particles have a particle size within a range of from 25 to 55 ⁇ m
- the average particle size of 70 ⁇ m indicates that the particles have an particle size within the range of from 40 to 100 ⁇ m.
- each powder of the ferrite powder particles was subjected to an X-ray analysis, whereby it was confirmed that each powder had a spinel structure and the metal contents corresponding to the feed composition as shown in Table 1.
- the electric resistance was obtained by measuring electric resistance of the samples of 200 mg by application of 100 V in the aforementioned manner by an insulation resistance meter.
- Each ferrite powder thus obtained was used by itself as a magnetic carrier powder. Namely, it was mixed with a commercially available two-component toner(an average particle size of 11.5 ⁇ 1.5 ⁇ m) to obtain a developer having a toner concentration of 11.5% by weight.
- the surface magnetic flux density of the magnetic roller for the magnetic brush development was 1000 Gauss; the rotational speed of the magnetic roller was 130 rpm and the rotational speed of the sleeve roller was 30 rpm. Further, the space between the magnet roller and the photosensitive material was 3.0 + 0.3 mm.
- the photosensitive material a CdS photosensitive material of binder type was used and the maximum surface electric potential was 800 V.
- the resolving power was measured by means of a test chart made by Data Quest Company.
- the image of the test chart was observed by naked eyes to evaluate the graininess.
- the evaluation was made in accordance with five ratings A to E where A represents the best and E represents the worst.
- the gradation was evaluated by observation with naked eyes. The evaluation was made by means of a grade scale comprising 13 grades and the expressed by the grade numbers (1- 13 ).
- the soft gradation was evaluated also by observation with naked eyes. In this case, the order of superiority was expressed by a number.
Abstract
Description
- The present invention relates to a magnetic carrier powder. More particularly, the present invention relates to a magnetic carrier powder to be used for magnetic brush development.
- Heretofore, as a magnetic carrier powder to be used for magnetic brush development, there has been used an iron powder or a soft ferrite powder and it has been believed that the average particle size of the powder should preferably be from 30 to 1000 µm.
- However, such a conventional carrier powder is not totally satisfactory in that it does not provide satisfactory image quality such as a resolving power ,graininess, black uniformity or gradation of the image.
- Under these circumstances, it is the primary object of the present invention to provide a magnetic carrier powder which is capable of providing an image having an improved image quality such as the resolving power, graininess, black uniformity or gradation.
- The present inventors have conducted extensive researches and as a result, have found that the object can be attained by reducing the ferrite powder particlas to have an average particle size smaller than that of the conventional ferrite particles. The present invention has . been accomplished based on this discovery.
- Namely, the present invention provides a magnetic carrier powder composed of ferrite powder particles having a spinel structure and an average particle size of less than 30 µm.
- There has hitherto been no instance where ferrite powder particles having such a small particle size have been used alone as a carrier.
- Now, the present invention will be described in detail with reference to the preferred embodiments.
- The magnetic carrier powder of the present invention is made of a ferrite having a spinel structure.
- As the ferrite having a spinel structure, there may be mentioned a so-called soft ferrite such as a 2-3 spinel or a 1-3 spinel, a magnetite (Fe304) or a maghemite ( y -Fe2O3).
- Among these ferrites, the following ferrites i) and ii) are particularly preferred in view of its magnetic characteristics.
- i) a spinel ferrite comprising at most 60 molar % of MO where M is Ni, Mn, Mg, Zn, Cu, Co or a combination thereof, as calculated as a divalent oxide, and at least 40 molar % of Fe203 as calculated as a trivalent metal oxide.
- In this case, when M is a combination of at least two kinds of metals, their proportions may be optionally selected.
- ii) a magnetite.
- Among the ferrites i), the following ferrites ia) and ib) are preferred.
- ia) a ferrite i) wherein M is Ni, Mn, Mg, Cu, Zn or a combination thereof. In this case, when M is a combination of at least two kinds of metals, . their proportions may be optionally selected.
- ib) a ferrite i) wherein M is a combination of Ni, Mn, Mg, Cu, Zn or a combination thereof, with at most 20 atom % of Co. In this case, when M is a combination of at least two kinds of metals selected from Ni, Mn, Mg, Cu and Zn, their proportions may be optionally selected.
- When such a ferrite ia) or ib) is used, the saturation magnetization becomes extremely high, whereby the deposition of the carrier on the photosensitive material or scattering of the carrier from the magnetic brush can be minimized.
- The ferrite powder particles having the above-mentioned composition may further contain . at most 5 molar % of an oxide of Ca, Bi, Cr, Ta, Mo, Si, V, B, Pb, K, Na, or Ba.
- Such ferrite powder particles have an average particle size of less than 30 µm.
- If the average particle size is 30 µm or greater, the image quality, particularly the resolving power, graininess, uniformity or gradation tends to be degraded. Further, the image quality tends to be of high contrast, which taxes the eyes of the observer.
- On the other hand, if the average particle size is too small, the deposition of the carrier particles on the photosensitive material or the scattering of the carrier tends to be pronounced and the flowability of the developer tends to be poor. Therefore, the average particle size should preferably be at least 5 µm. Particularly good results. are obtainable when the average particle size is from 5 to 25 µm.
- Further, the particle size distribution is usually such that about 70% of the total particles have a particle size falling within the range of + 30% of the average particle size.
- Such ferrite particles are used as a carrier without being coated with a coating layer on the surfaces or without being dispersed in a resin. Therefore, the magnetic carrier powder of the present invention has great mechanical strength and hardly undergoes thermal degradation, whereby the degradation of its properties with time is minimum and its useful life is very long. Further, the reduction of the saturation magnetization due to the decrease of the volume occupying rate is minimum and its production is quite easy.
- The ferrite powder particles constituting the magnetic carrier powder of the present invention preferably have an electric resistance of from 104 to 1014 Ω , more preferably from 10 5 to 1012 n, when 100 V is applied in the following manner.
- Namely, the measurement of the electric resistance of the ferrite powder particles is conducted in the following manner in accordnace with a magnetic brush development system. An N-pole and a S-pole are arranged to face each other with a magnetic pole distance of 8 mm so that the surface magnetic flux density of the magnetic poles becomes 1500 Gauss and the surface area of the facing poles is 10 x 30 mm. Between the magnetic poles, a pair of flat non-magnetic electrodes are disposed in parallel to each other with an electrode distance of 8 mm. Between the electrodes, 200 mg of a test sample is placed and the sample is held between the electrodes by the magnetic force. With this arrangement, the electric resistance is measured by an insulation resistance tester or an ampere meter.
- If the electric resistance as measured in such a manner exceeds 1014 Ω , the image density tends to be low. On the other hand,
- if the resistance is less than 104 Ω, the image quality tends to be of high contrast.
- Further, in the present invention, the saturation magnetization 0" m of the ferrite particles is preferably at least 35 emu/g, whereby the deposition of the carrier on the photosensitive material or the scattering of the carrier by repeated development operations can be minimized. In this case, better results are obtainable when the saturation magnetization σm is at least 40 emu/g.
- The magnetic carrier powder composed of such ferrite powder particles may be prepared in such a manner as disclosed in U. S. Patent No. 3,839,029, No. 3,914,181 or No. 3,926,657.
- Namely, firstly, the corresponding metal oxides are mixed. Then, a solvent such as water is added and the mixture is slurried, for instance, in a ball mill. Other additives such as a dispersing agent and a binder may be added as the case requires. Then, the slurry is granulated and dried by a spray drier. Thereafter, the granules thereby obtained are burned at a predetermined burning temperature in a predetermined burning atmosphere. The burning is conducted in a fluidized furnace, a rotary kiln or a tunnel furnace, whereby particles having the above-mentioned average particle size is efficiently produced. After the burning, the particles are pulverized or dispersed to obtain a desired particles size, whereby the magnetic carrier powder of the present inention is obtained.
- The magnetic carrier powder of the present invention is mixed with a toner to obtain a developer. In this case, the type of the toner to be used is not critical and any toner may be used. Further, the magnetic brush development system and the photosensitive material to be employed to obtain an electrostatic copy image are not critical and an electrostatic copy image can be obtained in accordance with a conventional magnetic brush development method.
- According to the present invention, an extremely good image quality is obtainable. Namely, the resolving power, graininess, black uniformity and gradation thereby obtained are extremely good. The image is of soft gradation, which does not very much tax the eyes of the observer.
- Further, the composition of the ferrite powder particles or the conditions for the burning may readily be varied to optionally change the quantity of magnetism or electric resistance so that images having various image densities and gradations may readily be obtained.
- Further, the ferrite powder particles do not have a coating layer or they are not incorporated in a resin. Therefore, the degradation of the characteristics is minimum even when they are used for a long period of time, and they have good durability and a long useful life. They are free from the reduction of the magnetic characteristics which is likely to be led when incorporated with a resin component. Further, the number of the steps for their production can be minimized and the production is easy, whereby the production costs will be low.
- Now, the present invention will be described in further detail with reference to Examples.
- Metal oxides were mixed at various ratios (calculated as a divalent metal oxide and Fe203 ) as shown in Table 1. One part by weight of water was added to one part by weight of each mixture and mixed in a ball mill for five hours to obtain a slurry. Appropriate amounts of a dispersing agent and a binder were added.
- Then, the slurry was granulated and dried at a temperature of at least 150°C by a spray drier.
- Each granular product was burned in a fluidized furnace at the maximum temperature as shown in Table 1 in the atmosphere also as shown in Table 1. In Table 1, A represents an air atmosphere and N represents a nitrogen atmosphere.
- Thereafter, the granules were pulverized and classified to obtain ferrite powder particles having the average particle size as shown in Table 1. The average particle size is an average particle size of 5000 particles randomly selected under observation by an electron microscope. In the Table, the average particle size of 20 µm indicates that the particles have a particle size within a range of from 5 to 30 µm; the average particle size 40 11 m indicates that the particles have a particle size within a range of from 25 to 55 µm; and the average particle size of 70 µm indicates that the particles have an particle size within the range of from 40 to 100 µm.
- On the other hand, each powder of the ferrite powder particles was subjected to an X-ray analysis, whereby it was confirmed that each powder had a spinel structure and the metal contents corresponding to the feed composition as shown in Table 1.
- Then, the saturation magnetization σ m (emu/g) of each powder of the ferrite powder particles and the electric resistance ( n) under application of 100 V were measured. The results thereby obtained are shown in Table 1. The saturation magnetization σm was measured by magnetometer of a sample vibration type.
- The electric resistance was obtained by measuring electric resistance of the samples of 200 mg by application of 100 V in the aforementioned manner by an insulation resistance meter.
-
- Each ferrite powder thus obtained was used by itself as a magnetic carrier powder. Namely, it was mixed with a commercially available two-component toner(an average particle size of 11.5 ±1.5 µm) to obtain a developer having a toner concentration of 11.5% by weight.
- With use of each developer,magnetic brush development was carried out by means of a commercially available electrostatic copying machine and the image quality of the image thereby obtained was evaluated. In this case, the surface magnetic flux density of the magnetic roller for the magnetic brush development was 1000 Gauss; the rotational speed of the magnetic roller was 130 rpm and the rotational speed of the sleeve roller was 30 rpm. Further, the space between the magnet roller and the photosensitive material was 3.0 + 0.3 mm. As the photosensitive material, a CdS photosensitive material of binder type was used and the maximum surface electric potential was 800 V.
- The resolving power (lines/mm) was measured by means of a test chart made by Data Quest Company. The image of the test chart was observed by naked eyes to evaluate the graininess. The evaluation was made in accordance with five ratings A to E where A represents the best and E represents the worst.
- Further, the gradation was evaluated by observation with naked eyes. The evaluation was made by means of a grade scale comprising 13 grades and the expressed by the grade numbers (1-13).
- The soft gradation was evaluated also by observation with naked eyes. In this case, the order of superiority was expressed by a number.
- The results thereby obtained are shown in Table 2.
-
- From the results shown in Table 2, it is evident that the magnetic carrier powders of the present invention give far superior electrostatic images to those having an average particle size of at least 30 µm.
Claims (11)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AT83101193T ATE27380T1 (en) | 1982-02-13 | 1983-02-08 | MAGNETIC POWDER FOR TWO-COMPONENT TONER. |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP57021923A JPS58144839A (en) | 1982-02-13 | 1982-02-13 | Magnetic carrier particles |
JP21923/82 | 1982-02-13 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0086444A1 true EP0086444A1 (en) | 1983-08-24 |
EP0086444B1 EP0086444B1 (en) | 1987-05-20 |
Family
ID=12068585
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP83101193A Expired EP0086444B1 (en) | 1982-02-13 | 1983-02-08 | Magnetic carrier powder for two-component toner |
Country Status (6)
Country | Link |
---|---|
EP (1) | EP0086444B1 (en) |
JP (1) | JPS58144839A (en) |
AT (1) | ATE27380T1 (en) |
AU (1) | AU557231B2 (en) |
DE (1) | DE3371725D1 (en) |
DK (1) | DK161047C (en) |
Cited By (8)
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WO1992002861A1 (en) * | 1990-08-01 | 1992-02-20 | Eastman Kodak Company | Interdispersed two-phase ferrite composite and electrographic magnetic carrier particles therefrom |
WO1992005475A1 (en) * | 1990-09-14 | 1992-04-02 | Eastman Kodak Company | Interdispersed three-phase ferrite composite and electrographic magnetic carrier particles therefrom |
WO1993004408A1 (en) * | 1991-08-16 | 1993-03-04 | Eastman Kodak Company | Ferrite green beads and method of producing carrier particles |
EP0614129A1 (en) * | 1993-02-05 | 1994-09-07 | Kyocera Corporation | Magnetic carrier, developer comprising the carrier for developing latent electrostatic images, electrographic photoconductor, and image formation method using the same |
EP0689100A1 (en) * | 1994-06-22 | 1995-12-27 | Canon Kabushiki Kaisha | Carrier for electrophotography, two component type developer, and image forming method |
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JPH0664362B2 (en) * | 1982-12-15 | 1994-08-22 | 日立金属株式会社 | Ferrite Carrier for Electrophotography |
JPS60134249A (en) * | 1983-12-22 | 1985-07-17 | Fuji Elelctrochem Co Ltd | Ferrite carrier material for electrostatic copying |
JPS60135958A (en) * | 1983-12-23 | 1985-07-19 | Toda Kogyo Corp | Spherical magnetic carrier particles and their manufacture |
JPH0648394B2 (en) * | 1984-04-25 | 1994-06-22 | 富士電気化学株式会社 | Ferrite carrier material for electrostatic copying |
JPS60227266A (en) * | 1984-04-25 | 1985-11-12 | Fuji Elelctrochem Co Ltd | Ferrite carrier material for electrostatic copying |
JPH0648393B2 (en) * | 1984-04-25 | 1994-06-22 | 富士電気化学株式会社 | Ferrite carrier material for electrostatic copying |
JPS60227269A (en) * | 1984-04-26 | 1985-11-12 | Fuji Elelctrochem Co Ltd | Ferrite carrier material for electrostatic copying |
JPH0648395B2 (en) * | 1984-04-26 | 1994-06-22 | 富士電気化学株式会社 | Ferrite carrier material for electrostatic copying |
JP2518684B2 (en) * | 1989-04-10 | 1996-07-24 | 株式会社巴川製紙所 | Developer for reversal development |
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JP4682062B2 (en) | 2006-03-07 | 2011-05-11 | 株式会社リコー | Carrier, developer, image forming method and process cartridge |
JP4861233B2 (en) | 2006-04-17 | 2012-01-25 | 株式会社リコー | Core particle for electrophotographic developer carrier, production method thereof, electrophotographic developer and image forming method |
JP5333882B2 (en) | 2006-09-14 | 2013-11-06 | 株式会社リコー | Electrophotographic developer |
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US3914181A (en) * | 1971-07-08 | 1975-10-21 | Xerox Corp | Electrostatographic developer mixtures comprising ferrite carrier beads |
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US4042518A (en) * | 1973-09-05 | 1977-08-16 | Xerox Corporation | Stoichiometric ferrite carriers |
EP0010732A1 (en) * | 1978-10-27 | 1980-05-14 | TDK Corporation | Magnetic toner powder |
DE3132494A1 (en) * | 1980-09-22 | 1982-05-06 | Compagnie Internationale pour l'Informatique CII-Honeywell Bull, 75960 Paris | Magnetic recording element |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
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JPS57177162A (en) * | 1981-04-24 | 1982-10-30 | Nec Corp | Developer for electrophotography |
-
1982
- 1982-02-13 JP JP57021923A patent/JPS58144839A/en active Pending
-
1983
- 1983-02-08 AT AT83101193T patent/ATE27380T1/en not_active IP Right Cessation
- 1983-02-08 EP EP83101193A patent/EP0086444B1/en not_active Expired
- 1983-02-08 DE DE8383101193T patent/DE3371725D1/en not_active Expired
- 1983-02-11 DK DK060983A patent/DK161047C/en not_active IP Right Cessation
- 1983-02-11 AU AU11360/83A patent/AU557231B2/en not_active Expired
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GB751623A (en) * | 1953-11-27 | 1956-07-04 | Steatite Res Corp | Improvements in or relating to ferromagnetic ceramic bodies |
DE1449403B2 (en) * | 1962-07-25 | 1976-07-29 | N.V. Philips' Gloeilampenfabrieken, Eindhoven (Niederlande) | METHOD OF MANUFACTURING A POLYCRYSTALLINE NICKEL FERRITE BODY AND A MAGNETIC HEAD MADE FROM SUCH A FERRITE BODY |
US3509058A (en) * | 1966-08-23 | 1970-04-28 | Philips Corp | Ferromagnetic materials on the basis of nickel ferrite or nickel-zinc ferrite |
US3839029A (en) * | 1971-07-08 | 1974-10-01 | Xerox Corp | Electrostatographic development with ferrite developer materials |
US3914181A (en) * | 1971-07-08 | 1975-10-21 | Xerox Corp | Electrostatographic developer mixtures comprising ferrite carrier beads |
DE2359424A1 (en) * | 1971-09-24 | 1974-06-06 | Montedison Spa | PROCESS FOR MANUFACTURING SIMPLE, MIXED OR SUBSTITUTED SOFT FERRITES OR BARIUM TITANATE |
DE2261183A1 (en) * | 1971-12-14 | 1973-06-20 | Thomson Csf | POLYCRYSTALLINES, FERROMAGNETIC MATERIAL AND METHOD FOR MANUFACTURING IT |
US3929657A (en) * | 1973-09-05 | 1975-12-30 | Xerox Corp | Stoichiometric ferrite carriers |
US4042518A (en) * | 1973-09-05 | 1977-08-16 | Xerox Corporation | Stoichiometric ferrite carriers |
EP0010732A1 (en) * | 1978-10-27 | 1980-05-14 | TDK Corporation | Magnetic toner powder |
DE3132494A1 (en) * | 1980-09-22 | 1982-05-06 | Compagnie Internationale pour l'Informatique CII-Honeywell Bull, 75960 Paris | Magnetic recording element |
Cited By (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0136599A2 (en) * | 1983-09-30 | 1985-04-10 | Kabushiki Kaisha Toshiba | Barium ferrite magnetic powder and recording medium employing the same |
EP0136599A3 (en) * | 1983-09-30 | 1986-01-08 | Kabushiki Kaisha Toshiba | Barium ferrite magnetic powder and recording medium employing the same |
US4582623A (en) * | 1983-09-30 | 1986-04-15 | Kabushiki Kaisha Toshiba | Barium ferrite magnetic powder and recording medium employing the same |
WO1992002861A1 (en) * | 1990-08-01 | 1992-02-20 | Eastman Kodak Company | Interdispersed two-phase ferrite composite and electrographic magnetic carrier particles therefrom |
WO1992005475A1 (en) * | 1990-09-14 | 1992-04-02 | Eastman Kodak Company | Interdispersed three-phase ferrite composite and electrographic magnetic carrier particles therefrom |
WO1993004408A1 (en) * | 1991-08-16 | 1993-03-04 | Eastman Kodak Company | Ferrite green beads and method of producing carrier particles |
EP0614129A1 (en) * | 1993-02-05 | 1994-09-07 | Kyocera Corporation | Magnetic carrier, developer comprising the carrier for developing latent electrostatic images, electrographic photoconductor, and image formation method using the same |
US5981127A (en) * | 1993-02-05 | 1999-11-09 | Kyocera Corporation | Magnetic carrier and developer comprising the carrier for developing latent electro-static images |
US6077637A (en) * | 1993-02-05 | 2000-06-20 | Kyocera Corporation | Magnetic carrier developer comprising the carrier for developing latent electrostatic images electrophotographic photoconductor and image formation method using the same |
EP0689100A1 (en) * | 1994-06-22 | 1995-12-27 | Canon Kabushiki Kaisha | Carrier for electrophotography, two component type developer, and image forming method |
US6316156B1 (en) | 1994-06-22 | 2001-11-13 | Canon Kabushiki Kaisha | Carrier for electrophotography, two component type developer, and image forming method |
US7166404B2 (en) * | 2001-03-02 | 2007-01-23 | Ricoh Company, Ltd. | Carrier for developer for developing electrostatic latent image, image forming method using same and image forming apparatus using same |
US7179577B2 (en) | 2001-03-02 | 2007-02-20 | Ricoh Company, Ltd. | Carrier for developer for developing electrostatic latent image, image forming method using same and image forming apparatus using same |
US20120126165A1 (en) * | 2010-11-18 | 2012-05-24 | Samsung Electro-Mechanics Co., Ltd. | Magnetic material composition for ceramic electronic component, method of manufacturing the same, and ceramic electronic component using the same |
US8597534B2 (en) * | 2010-11-18 | 2013-12-03 | Samsung Electro-Mechanics Co., Ltd. | Magnetic material composition for ceramic electronic component, method of manufacturing the same, and ceramic electronic component using the same |
Also Published As
Publication number | Publication date |
---|---|
EP0086444B1 (en) | 1987-05-20 |
DK161047C (en) | 1991-10-28 |
DK60983D0 (en) | 1983-02-11 |
AU1136083A (en) | 1983-08-18 |
DK161047B (en) | 1991-05-21 |
AU557231B2 (en) | 1986-12-11 |
ATE27380T1 (en) | 1987-06-15 |
JPS58144839A (en) | 1983-08-29 |
DE3371725D1 (en) | 1987-06-25 |
DK60983A (en) | 1983-08-14 |
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