US3916830A - Magnetic brush developer - Google Patents

Magnetic brush developer Download PDF

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Publication number
US3916830A
US3916830A US497523A US49752374A US3916830A US 3916830 A US3916830 A US 3916830A US 497523 A US497523 A US 497523A US 49752374 A US49752374 A US 49752374A US 3916830 A US3916830 A US 3916830A
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US
United States
Prior art keywords
developer
extending
cylinder
guide elements
scraping plate
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.)
Expired - Lifetime
Application number
US497523A
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English (en)
Inventor
Motoki Kojima
Nin-Ichi Kamogawa
Haruo Fujii
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Konica Minolta Inc
Original Assignee
Konica Minolta Inc
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Filing date
Publication date
Application filed by Konica Minolta Inc filed Critical Konica Minolta Inc
Application granted granted Critical
Publication of US3916830A publication Critical patent/US3916830A/en
Assigned to KONICA CORPORATION reassignment KONICA CORPORATION RELEASED BY SECURED PARTY (SEE DOCUMENT FOR DETAILS). Assignors: KONISAIROKU PHOTO INDUSTRY CO., LTD.
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
    • G03G15/08—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer
    • G03G15/09—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer using magnetic brush

Definitions

  • An improved scraping plate in combination with a magnetic brush developer, which has an [52] U S U 118/637, 118/203 upwardly extending edge contacting the magnetic [51] G03G 13/08 brush for removal of residual developer materials and [58] Fie'ld of 203 a plurality of guide elements for moving the scraped 15/2565 residual developer materials axially whereby the developer materials are more uniformally mixed.
  • This invention relates to a developing apparatus with a magnetic brush for use in visualization of an electrostatic latent image.
  • An electrostatic latent image can be formed in various methods. Commonly known is a method wherein photo image corresponding to an original is projected on a uniformly charged photo-conductive insulating layer and the charge on exposed portion is dissipated to form an electrostatic latent image. An alternative is the method wherein needle end discharge is effected imageweise on the insulating layer to form an electrostatic photographic latent image.
  • a developer which comprises, for example, a magnetic carrier and a toner.
  • the developer is adhered to the peripheral surfaces of a cylindrical magnet assembly comprising a plurality of magnets arranged at the peripheral surface thereof with alternate polarity whereby the developer is kept in brush-shaped configuration.
  • the developer kept in brush-shaped configuration is moved along the peripheral surfaces of the cylindrical magnet assembly and brought into contact with the electrostatic latent image so that the toner contained in the developer can be selectively adhered to the latent image thereby developing and visualizing the latter.
  • the above-mentioned developing method is generally referred to as magnetic developing process, for which a number of apparatus have been proposed.
  • an apparatus wherein a developer is adhered directly on the peripheral surfaces of the cylindrical magnet assembly, which is rotated in turn so that the developer can be conveyed and brought into contact with the electrostatic latent image.
  • an apparatus wherein a developer is adhered to the peripheral surface of a freely rotate cylindrical (non-magnetic) supporting member, which has magnets located inside thereof, and the developer is adhered to the peripheral surface of said cylindrical member, which is rotated in turn so that the developer can be conveyed and brought into contact with the electrostatic latent image.
  • a cylindrical (non-magnetic) supporting member has magnets located at the inner peripheral surface thereof, each of said magnets having a magnetic pole alternately different in polarity along the innerperipheral surface of said supporting member.
  • a developer is conveyed in the direction opposite to the direction of rotation of the magnets and brought into contact with an electrostatic latent image by rotating the cylindrical magnets while the developer is selfrotated.
  • a flat scraping plate which scrapes off the developer from the peripheral surface of a cylindrical magnet assembly or a cylindrical supporting member after the developer has passed a developing position at which it is brought into contact with an electrostatic latent image.
  • This scraping operation is effected in order to keep the magnetic carrier-to-toner ratio constant throughout the operation so that the developed image having aneven and uniform density can be obtained at any time by the development.
  • the magnetic carrier-to-toner ratio of a developer will vary in response to the progress of development because the toner is consumed.
  • the developer having a varied magnetic carrier-to-toner ratio must be scraped off wholly or partly from the peripheral surface of the cylindrical magnet assembly comprising a plurality of magnets or the cylindrical supporting member having magnets located therein and then returned to a container accommodating a fresh developer, so as to adjust again the magnetic carrier-to-toner ratio at a constant level required for development.
  • the developer conveyed to a developing position can be kept at a desired level of the magnetic carrier-to-toner ratio at any time.
  • the prior art flat scraping plate has an inherent disadvantage such that a large part of the developer will move in the direction of rotation of the magnetic brush and not in the axial direction of the latter within the container, because the plate allows the developer to drop only in the direction of the peripheral surface of the brush within the container after it has scraped off the developing formulation from the latter.
  • the portion having a low toner density is maintained without being improved if it is present in the developer. Consequently, the photo image visualized by means of such developing apparatus will have a streaky shade. Moreover, if the toner concentration of the developer becomes low, the magnetic carrier itself may adhere to the developing surface. Also, in the portion where the toner concentration is too high, the toner may adhere to the nonimage portion of the developing surface to produce fog.
  • the present invention has for its object to eliminate the above-mentioned disadvantage in the developing apparatus with a magnetic brush and provide an apparatus for developing an electrostatic latent image with a magnetic brush whereby toner concentration can be kept uniformly at any time so as to obtain a uniform developing effect.
  • FIG. 1 is a longitudinal sectional view of one embodiment of the developing apparatus with a magnetic brush according to the invention
  • FIG. 2 is an enlarged perspective view of the developer scraping plate of the apparatus shown in FIG. 1,
  • FIG. 3 is an enlarged perspective view of another embodiment of the developer scraping plate.
  • FIG. 4 is a sectional view taken along line A A of FIG. 3.
  • reference numerals 1, 2, 3, 4 and 5 denote a magnet respectively.
  • the magnet l is located close to a developing position and serves to form a developer comprising a toner and an iron dust carrier into brushshaped configuration.
  • Reference numeral 6 denotes a cylindrical supporting member which surrounds the magnets l, 2, 3, 4 and 5 and is rotated in the direction as shown by arrow A.
  • Reference numeral 7 denotes a developing formulation comprising an iron dust carrier and a toner, which is supported in the periphery of the cylindrical supporting member 6 and is moved by rotation of the supporting member in the direction as shown by arrow A.
  • Reference numeral 8 denotes a surface to be developed movable in the direction as shown by arrow B, 10 a container accomodating a developer and 11 an edge for putting the ear of the developing brush in order.
  • Reference numeral 9 denotes a scraping plate which scrapes off the developer on the cylindrical supporting member 6 and has a shape as shown in FIG. 2.
  • the scraping plate 9 is mounted close to the cylindrical supporting member 6.
  • This plate comprises a base portion 21 which acts to scrape off the developer from the supporting member, inclined raised portions 22, 22 which are spaced apart from one another at the rearward edge of the base portion and inclined wing portions 23, 24 and 23, 24 which are integrally formed on both sides of each of the raised portions.
  • FIG. 3 and FIG. 4 show another embodiment of the invention.
  • a scraping plate 30 has a structure similar to that of the scraping plate 9 shown in FIG. 1 and FIG. 2 and includes a base portion 31, projecting parts 32 and inclined wing portions 33, 34. Further, the wing portions 33, 34 have developer receiving portions 35, 36 secured at their respective forward ends.
  • Below the scraping plate 30 is fixed rigidly an auxiliary plate 41, which has inclined wing portions 37, 38.
  • the wing portions 33, 34 of the scraping plate 30 and the wing portions 37, 38 of the auxiliary plate 41 are alternately located as shown in FIG. 3.
  • the wing portions 37, 38 have developer receiving portions 39, 40 at their respective forward ends. The developer will drop partly between the wing portion 33 and the wing portion 34 adjacent thereto, and the remainder will drop between the wing portion 37 and the wing portion 38 adjacent thereto.
  • the amount of the developer which is accommodated in the container may become uneven.
  • the bottom of the container 10 there is accommodated a developer enough to fill the space between the container and the cylindrical supporting member 6, so that there does not occur unevenness in the length of the ear of the developing brush due to unevenness in the amount of toner. This ensures, in combination with the fact the edge 11 is provided to put the ear of the brush in order, that unevenness in the amount of developer does not exert ill influence on developing effect.
  • an apparatus for developing an electrostatic latent image comprising a magnetic brush formed on a cylindrical member and disposed within a trough, a particulate developer comprising a magnetic carrier and a toner disposed in said trough, said cylindrical member partially immersed in said developer, means for rotating said cylinder, means for passing a latent image carrier in proximity to and in contact with the brush thereby developing said image, and scraping means for removing residual developer from said cylindrical member for return to said trough after development, said scraping means being located downstream of the zone of image development and extending along the longitudinal extent of said cylinder, the improvement which comprises said scraping means comprising a scraping plate extending upwardly and along said longitudinal extent and having a linear front edge in close proximity to said cylinder thereby adapted to remove the residual developer, said scraping means further comprising a plurality of transversely directed and oppositely inclined guide elements extending from the rear edge of said scraping plate for moving at least a part of the scraped residual developer axially of said cylinder whereby the magnetic
  • said guide elements comprising two groups of the guide elements, a first group of the guide elements being spaced along said longitudinal extent of said cylinder and extending from the rear edge of said scraping plate, a second group of the guide elements being individually spaced under and between two adjacent guide elements of said first group and rearwardly extending from the rear edge of said scraping plate.
  • said guide elements comprise a plurality of spaced panels rearwardly extending from the rear edge of said scraping plate and a panel element extending from each lateral edge of each said spaced panel and directed downwardly and outwardly with respect to said spaced panels and said scraping plate.
  • An apparatus for developing an electrostatic latent image comprising a rotatable magnetic brush formed on a cylindrical member and disposed within a trough, a particulate developer comprising a magnetic carrier and a toner disposed in said trough, said cylindrical member partially immersed in said developer means for passing a latent image carrier in proximity to and in contact with the magnetic brush thereby developing said image, a fixed scraping plate located downstream of the zone of image development extending along the longitudinal extent of said cylinder and having an upwardly extending front edge in close proximity to said cylinder thereby removing residual developer from the cylinder for return to said trough, said plate including a plurality of spaced panels extending rearwardly from the rear edge of said plate, and a panel element extending from each lateral edge of each said spaced panel and directed downwardly and outwardly with respect to said spaced panels and said scraper plate, whereby developer material removed from said cylinder is moved axially of said cylinder by each of said panel panel elements to more uniformly mix the carrier and toner particles.
US497523A 1971-05-26 1974-08-15 Magnetic brush developer Expired - Lifetime US3916830A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP1971042359U JPS563720Y2 (de) 1971-05-26 1971-05-26

Publications (1)

Publication Number Publication Date
US3916830A true US3916830A (en) 1975-11-04

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ID=12633824

Family Applications (1)

Application Number Title Priority Date Filing Date
US497523A Expired - Lifetime US3916830A (en) 1971-05-26 1974-08-15 Magnetic brush developer

Country Status (4)

Country Link
US (1) US3916830A (de)
JP (1) JPS563720Y2 (de)
DE (1) DE2225287B2 (de)
GB (1) GB1376978A (de)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4048958A (en) * 1976-03-08 1977-09-20 Fuji Xerox Co., Ltd. Magnetic brush developing device
US4095883A (en) * 1976-02-02 1978-06-20 Xerox Corporation Magnetic mixing apparatus and process
US4102306A (en) * 1976-05-31 1978-07-25 Konishiroku Photo Industry Co., Ltd. Developing roller and rinsing device
US4119060A (en) * 1976-07-16 1978-10-10 Ricoh Co., Ltd. Toner charging apparatus
DE3005756A1 (de) * 1979-02-15 1980-08-28 Canon Kk Entwicklungseinrichtung

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5334921Y2 (de) * 1974-07-05 1978-08-26
JPS53111738A (en) * 1977-03-11 1978-09-29 Toshiba Corp Developing device of magnetic brush type
JPS61272770A (ja) * 1985-05-20 1986-12-03 イ−ストマン　コダック　カンパニ− 磁気ブラシアプリケ−タの緊張可能なそぎ取り装置
JP5005802B2 (ja) * 2010-07-29 2012-08-22 シャープ株式会社 現像装置及びこれを備えた画像形成装置

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US438143A (en) * 1890-10-14 Scraper for cleaning the peripheries of rolls
US1201971A (en) * 1916-01-21 1916-10-17 Jacob Kaiser Scraper for printing-rollers.
US3233586A (en) * 1961-07-27 1966-02-08 Lumoprint Zindler Kg Devices for the application of developer powder
US3319563A (en) * 1964-09-18 1967-05-16 Clarence M Champion Ink separator

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US438143A (en) * 1890-10-14 Scraper for cleaning the peripheries of rolls
US1201971A (en) * 1916-01-21 1916-10-17 Jacob Kaiser Scraper for printing-rollers.
US3233586A (en) * 1961-07-27 1966-02-08 Lumoprint Zindler Kg Devices for the application of developer powder
US3319563A (en) * 1964-09-18 1967-05-16 Clarence M Champion Ink separator

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4095883A (en) * 1976-02-02 1978-06-20 Xerox Corporation Magnetic mixing apparatus and process
US4048958A (en) * 1976-03-08 1977-09-20 Fuji Xerox Co., Ltd. Magnetic brush developing device
US4102306A (en) * 1976-05-31 1978-07-25 Konishiroku Photo Industry Co., Ltd. Developing roller and rinsing device
US4119060A (en) * 1976-07-16 1978-10-10 Ricoh Co., Ltd. Toner charging apparatus
DE3005756A1 (de) * 1979-02-15 1980-08-28 Canon Kk Entwicklungseinrichtung

Also Published As

Publication number Publication date
DE2225287A1 (de) 1973-01-18
JPS482942U (de) 1973-01-13
DE2225287B2 (de) 1979-07-19
JPS563720Y2 (de) 1981-01-27
GB1376978A (en) 1974-12-11

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Date Code Title Description
AS Assignment

Owner name: KONICA CORPORATION, JAPAN

Free format text: RELEASED BY SECURED PARTY;ASSIGNOR:KONISAIROKU PHOTO INDUSTRY CO., LTD.;REEL/FRAME:005159/0302

Effective date: 19871021