EP0031503B1 - Magnetbürsten-Entwicklungsapparat - Google Patents

Magnetbürsten-Entwicklungsapparat Download PDF

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Publication number
EP0031503B1
EP0031503B1 EP80107642A EP80107642A EP0031503B1 EP 0031503 B1 EP0031503 B1 EP 0031503B1 EP 80107642 A EP80107642 A EP 80107642A EP 80107642 A EP80107642 A EP 80107642A EP 0031503 B1 EP0031503 B1 EP 0031503B1
Authority
EP
European Patent Office
Prior art keywords
magnetic
magnet
magnetic brush
development
toner
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
Application number
EP80107642A
Other languages
English (en)
French (fr)
Other versions
EP0031503A2 (de
EP0031503A3 (en
Inventor
Manabu Mochizuki
Masahide Harada
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.)
Ricoh Co Ltd
Original Assignee
Ricoh Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Family has litigation
First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=26335093&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=EP0031503(B1) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Priority claimed from JP180878A external-priority patent/JPS5495243A/ja
Priority claimed from JP2956978A external-priority patent/JPS54122131A/ja
Application filed by Ricoh Co Ltd filed Critical Ricoh Co Ltd
Priority to DE7979100081T priority Critical patent/DE2960948D1/de
Publication of EP0031503A2 publication Critical patent/EP0031503A2/de
Publication of EP0031503A3 publication Critical patent/EP0031503A3/en
Application granted granted Critical
Publication of EP0031503B1 publication Critical patent/EP0031503B1/de
Expired legal-status Critical Current

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Classifications

    • 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
    • G03G15/0921—Details concerning the magnetic brush roller structure, e.g. magnet configuration

Definitions

  • an apparatus in which a plurality of non-magnetic support members for supporting the magnetic brush thereon are disposed in close proximity to the surface of a latent electrostatic image bearing member, whereby the contact width w can be substantially increased.
  • the apparatus has some shortcomings that the apparatus is oversized and expensive. In order to eliminate such shortcomings, it is necessary to increase the contact width w by a single non-magnetic supporting member.
  • the contact width w of the magnetic brush is related to a gap d in the development section between a latent electrostatic image bearing member 7 and a non-magnetic support member 1 since the magnetic brush stands out at each magnetic pole.
  • the contact width w is greater in the bottom portion of the magnetic brush than in the top portion of the magnetic brush. Therefore, the smaller the gap d, the greater the contact width w.
  • a single magnet having at least one symmetrically disposed recess portion is provided adjacent said non-magnetic support member.
  • the long and short dash line indicates the distribution of the intensity of magnetic field of a conventional flat magnet, which has one peak of the intensity of magnetic field
  • the solid line indicates the distribution of the intensity of the magnetic field of the magnets of the present invention, which has two peaks of the intensity of the magnetic field.
  • the shape of the curve having two peaks of the intensity of magnetic field depends upon the size of the concave portion formed in the magnet. Namely, when the width a of the concave portion of the magnet is constant and the depth b of the concave portion is changed, the greater the depth b, the greater central dropping of the curve of the intensity of magnetic field, and when the depth b is constant and the width a changes, the greater the width a, the lower the two peaks.
  • the ratio a : b is 4:1
  • the distribution of the intensity of magnetic field is shown by the solid line 14 and, when the ratio a : b is 4:2, the distribution of the intensity of magnetic field is shown by a broken line 15.
  • the magnets for the present invention can be made by various methods.
  • the simplest method is to mold a ferromagnetic material and magnetize it and form a concave portion in the thus made magnet as desired by a diamond cutter.
  • Another method is to form a desired concave portion in a ferromagnetic material first and to magnetize later.
  • the magnets are composed of pieces of magnets.
  • one magnetic rod with predetermined concave portions at desired magnetic pole portions can be used as well.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Magnetic Brush Developing In Electrophotography (AREA)

Claims (4)

1. Entwicklungseinrichtung mit Magnetbürste, in welcher ein magnetisches Pulver enthaltender Entwickler an eine nichtmagnetisches Trägerteil angezogen wird, in welchem ein Magnet untergebracht ist, und in welcher der an das nichtmagnetische Trägerteil angezogene Entwickler in einem Entwicklungsabschnitt zum Entwickeln des latenten, elektrostatischen Bildes in Kontakt mit einem das latente, elektrostatische Bild tragenden Teil gebracht wird, wobei der Magnet im wesentlichen einen Magnetpolteil aufweist, welcher ein Magnetfeld mit einer Anzahl Intensitätsspitzen des Magnetfeldes in dem Entwicklungsabschnitt erzeugen kann, dadurch gekennzeichnet, daß ein einziger Magnet (11, 12, 13, 16) mit zumindest einer symmetrisch angeordneten Vertiefung angrenzend an den nichtmagnetischen Trägerteil (10) vorgesehen ist.
2. Entwicklungseinrichtung mit Magnetbürste nach Anspruch 1, dadurch gekennzeichnet, daß der Magnet (11) eine flache, konkave Vertiefung aufweist.
3. Entwicklungseinrichtung mit Magnetbürste nach Anspruch 1, dadurch gekennzeichnet, daß der Magnet (11) eine gewöblte, konkave Vertiefung aufweist.
4. Entwicklungseinrichtung mit Magnetbürste nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß der Magnet (16) mindestens zwei Vertiefungen aufweist.
EP80107642A 1978-01-11 1979-01-11 Magnetbürsten-Entwicklungsapparat Expired EP0031503B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE7979100081T DE2960948D1 (en) 1978-01-11 1979-01-11 Magnetic brush development apparatus

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP1808/78 1978-01-11
JP180878A JPS5495243A (en) 1978-01-11 1978-01-11 Magnetic brush developing device
JP2956978A JPS54122131A (en) 1978-03-15 1978-03-15 Magnetic brush developing device
JP29569/78 1978-03-15

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
EP79100081.3 Division 1979-01-11

Publications (3)

Publication Number Publication Date
EP0031503A2 EP0031503A2 (de) 1981-07-08
EP0031503A3 EP0031503A3 (en) 1981-09-09
EP0031503B1 true EP0031503B1 (de) 1985-08-07

Family

ID=26335093

Family Applications (2)

Application Number Title Priority Date Filing Date
EP80107642A Expired EP0031503B1 (de) 1978-01-11 1979-01-11 Magnetbürsten-Entwicklungsapparat
EP19790100081 Expired EP0003134B1 (de) 1978-01-11 1979-01-11 Magnetbürsten-Entwicklungsvorrichtung

Family Applications After (1)

Application Number Title Priority Date Filing Date
EP19790100081 Expired EP0003134B1 (de) 1978-01-11 1979-01-11 Magnetbürsten-Entwicklungsvorrichtung

Country Status (2)

Country Link
EP (2) EP0031503B1 (de)
CA (1) CA1135046A (de)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60229074A (ja) * 1984-04-27 1985-11-14 Toshiba Corp トナ−濃度検出装置
EP0349326B1 (de) * 1988-07-01 1994-01-05 Canon Kabushiki Kaisha Entwicklungsgerät
EP2018561A2 (de) 2006-05-10 2009-01-28 Koninklijke Philips Electronics N.V. Magnetisches system
JP6938167B2 (ja) 2016-03-08 2021-09-22 キヤノン株式会社 画像形成装置

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2545494A1 (de) * 1974-10-10 1976-04-22 Canon Kk Entwicklungseinrichtung
DE2452879A1 (de) * 1974-11-07 1976-05-20 Hitachi Metals Ltd Elektrostatische entwicklungsvorrichtung

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE7104099U (de) * 1971-07-08 Addressograph Multigraph Corp Magnetbürstenentwickler zum Entwickeln elektrostatisch geformter Bilder auf Blatt material
US3333572A (en) * 1965-04-27 1967-08-01 Rca Corp Electrostatic printing
US3402698A (en) * 1966-06-06 1968-09-24 Konishiroku Photo Ind Magnet assembly for magnetic developing brush and developing apparatus for electrostatic process
JPS475648U (de) * 1971-02-13 1972-09-19
US3939801A (en) * 1973-09-10 1976-02-24 Minolta Camera Kabushiki Kaisha Magnetic brush developing apparatus
US4048958A (en) * 1976-03-08 1977-09-20 Fuji Xerox Co., Ltd. Magnetic brush developing device

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2545494A1 (de) * 1974-10-10 1976-04-22 Canon Kk Entwicklungseinrichtung
DE2452879A1 (de) * 1974-11-07 1976-05-20 Hitachi Metals Ltd Elektrostatische entwicklungsvorrichtung

Also Published As

Publication number Publication date
EP0031503A2 (de) 1981-07-08
CA1135046A (en) 1982-11-09
EP0003134A1 (de) 1979-07-25
EP0003134B1 (de) 1981-10-14
EP0031503A3 (en) 1981-09-09

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