EP0203492A1 - Dispositif de grattoir tendu pour applicateur à brosse magnétique - Google Patents

Dispositif de grattoir tendu pour applicateur à brosse magnétique Download PDF

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Publication number
EP0203492A1
EP0203492A1 EP86106810A EP86106810A EP0203492A1 EP 0203492 A1 EP0203492 A1 EP 0203492A1 EP 86106810 A EP86106810 A EP 86106810A EP 86106810 A EP86106810 A EP 86106810A EP 0203492 A1 EP0203492 A1 EP 0203492A1
Authority
EP
European Patent Office
Prior art keywords
sleeve
blade
skive
skiving
magnetic
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
Application number
EP86106810A
Other languages
German (de)
English (en)
Other versions
EP0203492B1 (fr
Inventor
Richard Albert Weitzel
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.)
Eastman Kodak Co
Original Assignee
Eastman Kodak Co
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
Application filed by Eastman Kodak Co filed Critical Eastman Kodak Co
Publication of EP0203492A1 publication Critical patent/EP0203492A1/fr
Application granted granted Critical
Publication of EP0203492B1 publication Critical patent/EP0203492B1/fr
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

Definitions

  • This invention relates to electrographic recording and, more particularly, to apparatus for stripping magnetically attractive developer from the surface of the magnetic brush applicator after being used to develop an electrostatic image.
  • an electrographic development system comprising a magnetic brush applicator and a magnetic development mix.
  • the applicator basically comprises a non-magnetic cylindrical sleeve having a rotatably driven magnetic core piece positioned therein.
  • the magnetic core piece is driven at a high speed (e.g. 1500 RPM).
  • the magnetic developer comprises a mixture of thermoplastic toner particles and magnetically "hard” carrier particles, the latter having relatively high magnetic coercivity and remanence.
  • Rotational movement of the applicator's core piece serves to transport the development mix over the sleeve's outer surface and into contact with an electrostatic image- bearing surface located at a development zone.
  • the electrostatic forces associated with the image overcome the triboelectric attraction between toner and carrier, thereby stripping the toner from the carrier and depositing it on the image to effect development thereof.
  • the partially denuded carrier particles are returned to a reservoir to be replenished with toner particles.
  • skives made from thin strips (30-100 microns thick) of plastic or non-magnetic metal are commonly supported along one edge by a rigid member which is positioned to urge the free edge of the skive into contact with the periphery of the applicator's sleeve. Similar skiving devices are disclosed in U.S. Patent Nos. 4,328,762 and 4,391,503.
  • Stripping skives of the type disclosed above are sometimes difficult to maintain in alignment and in uniform contact with the periphery of the magnetic brush's non-magnetic sleeve. This is particularly true when the sleeve is rotatably driven. Non-uniform contact produces non-uniform wear of the blade, producing worn spots or "steps" in which developer may become trapped. Moreover, non-uniform contact will produce differential frictional heating which can cause such trapped developer to agglomerate and form large "flakes" which adversely affect image quality.
  • an object of this invention is to provide an improved skiving apparatus which is significantly easier to maintain in alignment and in uniform contact with the outer sleeve of a magnetic brush applicator, whereby the above-identified problems are reduced.
  • the skiving apparatus of the invention comprises an elongated and flexible skive, and means for producing tension in the skive to provide a straight scraping edge which, by proper positioning of the tensioning means relative to the magnetic brush sleeve, can contact the sleeve with substantially uniform pressure over its length.
  • the blade itself is made of a magnetically attractive material, such as "blue steel", so as to be attracted to the brush sleeve by the internal magnetic forces.
  • a magnetic brush applicator 10 of the type commonly used in electrographic copiers for applying a development mix D to a dielectric recording member M to effect development of an electrostatic image formed thereon basically comprises a non-magnetic cylindrical sleeve 12 having a multi-pole, magnetic core piece 14 concentrically arranged therein.
  • Conventional drive means (not shown) are provided for rotatably driving core piece 14 in the direction of arrow A, and, optionally, for rotatably driving sleeve 12 in the direction indicated by arrow B.
  • Fritz et al U.S.
  • the effect of the rotational movement of core piece 14 is to advance magnetic developer over the sleeve surface (in a direction indicated by arrow C) from a reservoir 16 to a development zone 18 at which point the developer contacts the electrostatic image borne by the dielectric recording element M.
  • Developer D may be of the two-component variety comprising a mixture of either magnetic or magnetically-attractive carrier particles and thermoplastic toner particles.
  • the developer could be of the single component type in which the toner particles themselves are magnetically attractive.
  • the apparatus of the invention as described below, is particularly useful with development systems of the type disclosed in the aforementioned Fritz et al patent. It will be understood, however, that the invention does have utility with a variety of different development systems.
  • a tensionable skive blade 22 is provided in accordance with the present invention.
  • skive blade 22 comprises an elongated strip 24 of flexible and thereby tensionable material.
  • such material is a magnetically attractive material, such as "blue steel", having a thickness of between 25 and 250 microns.
  • a preferred width for the skive is between 10 and 50 millimeters.
  • Means 26 are provided for exerting equal but opposite longitudinal forces (i.e., end loads) at spaced positions 24a, 24b along the skive blade in order to provide tension in the blade, the function of such tension being to provide a straight, unwavering edge 24c which, when brought into contact with the periphery of sleeve 12, will provide uniform pressure along its entire length.
  • skive material may be non-magnetic, such as aluminum or even plastic film
  • a magnetic material is preferred because of its attraction to the magnetic core piece 14 within sleeve 12. Such magnetic attraction reduces, if not eliminates, the need for mechanically loading the skive in the radial direction, i.e. toward the axis of rotation of the magnetic brush.
  • Skive-tensioning means 26 may comprise, for example, a pair of end plates 30, 32 which are maintained in spaced relation by a connecting rod 34.
  • the opposite ends of rod 34 are connected to end plates 30, 32 at points intermediate the ends of the plates, thereby providing fulcrum points about which plates 30, 32 may pivot slightly.
  • the opposite ends of the flexible skive strip are connected (e.g. by screws) to beveled edges 30a, 32a located at one end of their respective end plates.
  • a turnbuckle 40, or the like, is connected between the opposite ends 30b, 32b of the end plates and serves, when tightened, to exert equal but opposite axial forces on the flexible skive strip 24 to produce a desired tension therein.
  • the skive tensioning means is mounted relative to sleeve 12 so that the tensioned skive strip contacts the sleeve periphery at a location approximately 90 degrees downstream of the development zone 18.
  • a pair of springs 42 may be provided to urge the skive into contact with the brush sleeve.
  • a variation of the skiving apparatus of the invention is shown to comprise a pair of tensionable skive strips 46, 48, which are connected to and stretch between a pair of spaced plates 50, 52.
  • Tensioning means 5 ., e.g. a compression spring, serves to exert equal but opposite forces on plates 50, 52 via connecting rods 56, 58.
  • Such an arrangement provides four skivinz edges, 46a, 46b, 48a and 48b, any one of which can be arranged to contact the applicator sleeve by merely changing the orientation of the assembly relative to the brush applicator.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Dry Development In Electrophotography (AREA)
  • Magnetic Brush Developing In Electrophotography (AREA)
EP19860106810 1985-05-20 1986-05-20 Dispositif de grattoir tendu pour applicateur à brosse magnétique Expired EP0203492B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US73551485A 1985-05-20 1985-05-20
US735514 1985-05-20

Publications (2)

Publication Number Publication Date
EP0203492A1 true EP0203492A1 (fr) 1986-12-03
EP0203492B1 EP0203492B1 (fr) 1989-08-23

Family

ID=24956119

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19860106810 Expired EP0203492B1 (fr) 1985-05-20 1986-05-20 Dispositif de grattoir tendu pour applicateur à brosse magnétique

Country Status (3)

Country Link
EP (1) EP0203492B1 (fr)
JP (1) JPS61272770A (fr)
DE (1) DE3665231D1 (fr)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2225287A1 (de) * 1971-05-26 1973-01-18 Konishiroku Photo Ind Magnetbuerstenentwicklungsvorrichtung
US4083633A (en) * 1976-06-28 1978-04-11 Xerox Corporation Blade cleaning holder
DE2758239A1 (de) * 1976-12-28 1978-07-06 Canon Kk Reinigungsblattvorrichtung
US4338880A (en) * 1978-09-19 1982-07-13 Minolta Camera Kabushiki Kaisha Magnetic brush development apparatus for use in electrophotographic copying machine
US4392735A (en) * 1980-06-04 1983-07-12 Minolta Camera Kabushiki Kaisha Magnetic brush developing apparatus
DE3343701A1 (de) * 1982-12-02 1984-06-07 Ricoh Co., Ltd., Tokio/Tokyo Reinigungseinrichtung

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2225287A1 (de) * 1971-05-26 1973-01-18 Konishiroku Photo Ind Magnetbuerstenentwicklungsvorrichtung
US4083633A (en) * 1976-06-28 1978-04-11 Xerox Corporation Blade cleaning holder
DE2758239A1 (de) * 1976-12-28 1978-07-06 Canon Kk Reinigungsblattvorrichtung
US4338880A (en) * 1978-09-19 1982-07-13 Minolta Camera Kabushiki Kaisha Magnetic brush development apparatus for use in electrophotographic copying machine
US4392735A (en) * 1980-06-04 1983-07-12 Minolta Camera Kabushiki Kaisha Magnetic brush developing apparatus
DE3343701A1 (de) * 1982-12-02 1984-06-07 Ricoh Co., Ltd., Tokio/Tokyo Reinigungseinrichtung

Also Published As

Publication number Publication date
JPS61272770A (ja) 1986-12-03
DE3665231D1 (en) 1989-09-28
EP0203492B1 (fr) 1989-08-23

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