EP0146825A2 - Dispositif électrostatique pour repousser le toneur dans une machine électrophotographique - Google Patents

Dispositif électrostatique pour repousser le toneur dans une machine électrophotographique Download PDF

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Publication number
EP0146825A2
EP0146825A2 EP84114583A EP84114583A EP0146825A2 EP 0146825 A2 EP0146825 A2 EP 0146825A2 EP 84114583 A EP84114583 A EP 84114583A EP 84114583 A EP84114583 A EP 84114583A EP 0146825 A2 EP0146825 A2 EP 0146825A2
Authority
EP
European Patent Office
Prior art keywords
toner
electrostatic
accordance
drum
repeller
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.)
Ceased
Application number
EP84114583A
Other languages
German (de)
English (en)
Other versions
EP0146825A3 (fr
Inventor
Abdullatif M. Kasu
Thomas Robson
Richard C. Fedder
Aubrey E. Thompson
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.)
Unisys Corp
Original Assignee
Burroughs Corp
Unisys Corp
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 Burroughs Corp, Unisys Corp filed Critical Burroughs Corp
Publication of EP0146825A2 publication Critical patent/EP0146825A2/fr
Publication of EP0146825A3 publication Critical patent/EP0146825A3/fr
Ceased 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
    • G03G15/0896—Arrangements or disposition of the complete developer unit or parts thereof not provided for by groups G03G15/08 - G03G15/0894
    • G03G15/0898—Arrangements or disposition of the complete developer unit or parts thereof not provided for by groups G03G15/08 - G03G15/0894 for preventing toner scattering during operation, e.g. seals

Definitions

  • the present invention relates to electrographic apparatus and to automatic means for preventing toner dust from migrating from the developer station to other parts of the apparatus.
  • Electrographic printer apparatus which utilize two-component toners i.e. toner plus carrier beads ; generally operate the magnetic brush or toner applicator roll at a higher rotative rate than those systems which employ single component toners since the quantity of toner is much less with the two component system.
  • All toner material consists of extremely fine powder-like material which can become airborne. Toner particles in a two component system are lighter in weight and non-magnetic whereas in a single component system the toner particles are heavier and hence cannot drift as readily in air and are magnetic so they can be held to the applicator roll by its negative field. The problem of toner migration due to the air turbulence created by the movement of the toner-carrier particles thus becomes a particular problem.
  • Brush-like seals at the edges of the rotatable photoreceptor drum tend to limit the ambient dust to a certain degree. Still, there is sufficient migration of the toner dust to other portions of the apparatus to produce unwanted deposits on bearings, moving parts such as gear trains, etc., and onto the copy itself making for unreliable and relatively dirty apparatus.
  • toner material with the carrier material (usually nonconductive beads) to form the developer generates a triboelectric charge.
  • the carrier beads usually have a (positive) +V e charge while the toner particles have a (negative) -V e charge.
  • Electrostatic attraction and replusion are well known phenomena. Electrostatic preciptators are used industrially to capture and remove all manner of waste products from the stack and flue effluent.
  • the present invention makes use of the repulsive effect of electrostatics.
  • a pair of substantially similar conducting and electrostatically charged members albeit carrying a - V e (negative) charge, are arranged in spaced apart ' relation to the photoreceptor recording drum of an electrophotographic apparatus.
  • the charged members are disposed across the width of the drum and adjacent to the developer station (or unit) in the apparatus.
  • Dielectric support members maintain the charged electrostatic elements in close proximity (but not touching) to the drum surface.
  • a spacing of a few ten thousandths of an inch is sufficient to effectively seal the area adjacent the drum and toner station against dust.
  • Application of a negative potential to the electrostatic charged members causes the negatively charged toner dust to be completely repelled from the area adjacent to each electrostatic member.
  • the present invention comprises a pair of conductive (e.g. copper) elongated, thin, strips mounted to respective dielectric, molded members.
  • the two assemblies are positioned adjacent to but separated from the periphery of the photoreceptor drum of an electrophotographic printer. So as to prevent the electrical field produced by the adjacent positively charged corotron from attracting toner dust a shunt or ground in the form of a grounded conductive member secured to the lowermost of the two electrostatic repeller members effectively shunts or grounds the field lines from the corotron preventing negatively charged toner from being attracted to the corotron.
  • conductive e.g. copper
  • This arrangement completely eliminates the toper dusting problem and keeps the area around the photoreceptor drum clean and assuring more legible copy.
  • the present invention relates to reprographic electrophotographic apparatus of the type described and claimed in USSN 429,861 filed September 30, 1982 in the name of Richard C. Fedder for "Toner Concentration Sensor For Electrographic Apparatus" assigned to the same assignee as the present invention.
  • dry copying apparatus in order to produce clean, clear, crisp, black printing (copy) on white paper for example, to a line definition generally acceptable to the eye as regular or standard printing, it is necessary to employ an extremely fine dry powder toner material.
  • the subject apparatus also utilizes what is characterized as a two component developer i.e. a finely powdered toner and larger carrier beads.
  • the carrier beads acquire a positive (+V e ) charge while the toner material acquires a negative (-V e ) charge.
  • some toner particles remain uncharged or go free to produce an ambient dust which migrates at random to all parts of the surrounding atmosphere and hardware.
  • the problem is solved by utilizing the phenomenon of attraction and replusion i.e. like charges repel one another while unlike changes attract.
  • the present invention is seen to include a rotatable photoreceptor drum 10 having a photoconductive surface 12 for receiving a visual image of information or data thereon.
  • a rotatable photoreceptor drum 10 having a photoconductive surface 12 for receiving a visual image of information or data thereon.
  • corotrons 14 The other corotron to the right of the first is not shown since it forms no part of this invention.
  • L-shaped glass filled nylon lower bar member 20 Located to the left and above the corotron 14, secured as by bolts 16 to the extrusion hardware frame 18, is an L-shaped glass filled nylon lower bar member 20. Member 20 is arranged to extend (from side to side) across the drum 10 in very close but noncontacting proximity thereto. Adjacent to but above and separated from the lower bar member 20 is an upper L-shaped glass filled nylon bar member 22.
  • Each bar member 20 and 22 is provided with a elongated fairly wide channel or groove 24 extending from end to end of the respective member.
  • One end of each member 20 and 22 is provided with a substantially rectangular aperture 26, which will be explained shortly.
  • An opposite integral portion of each bar member 20 and 22 is provided with a plurality of attachment holes 28 arranged in spaced apart relation on a thickened or raised land portion 30. The latter portion 30 extends from end to end of each bar strengthening element for retaining the attachment bolts 16.
  • the two mounting-support members 20 and 22 are otherwise identical in cross section, only their physical orientation is different.
  • the upper member 22 is angled as seen in Figure 1 so as to take advantage of the available hardware to which it is physically attached.
  • the lower member 20 is likewise situated to enable its attachment to available hardware structure. Since no corotron is used above the member 22 there is no need for a second shunt (to be described shortly) as is used with the lower member 22.
  • An elongated, relatively thin, conductive copper strip 32 one end of which is provided with an integral bent tang 34, Figure 2 including an attachement hole 36, is seated in the longitudinal groove or channel 24 in respective members 20 and 22.
  • the bent tang 34 is received within the rectangular aperture 26.
  • the physical mounting arrangement of the two members 20 and 22 is such that the flat planar facing portion of each copper strip 32 is generally oriented toward the surface of drum 10 with the strip 32 of lower member 20 being substantially parallel to the drum surface.
  • the two (upper and lower) electrostatic repelling devices 20 and 22 are disposed relative to a magnetic brush development roller member 38 mounted in close but non contacting proximity to drum 10.
  • the outer shell 39 of member 38 rotates past a plurality of internally disposed fixed magnets (not shown) to carry developer 40 (toner plus carrier) from a source (not shown) upwardly by the rotatable magnet member 38 into surface contact with drum 10 as members 10 and 38 are rotated during machine operation.
  • the shell of member 38 carries a B+ potential charge of approximately 300 volts.
  • the drum 10 is provided with a B+ potential of 750-800 volts.
  • the two electrostatic repeller devices are each provided with a negative potential of approximately - 1200 volts over leads 44 from a source (not shown).
  • a corotron 14, disposed below and to the right of roll 38 is maintained at a B+ potential of 4500 to 6000 volts over lead 48, from a source (not shown).
  • the present invention utilizes a shunt member 46, e.g. a copper strip, bent out of the main plane into a v-shape as seen in Figure 1. Attachment notches 48 are provided along its length so as to secure member 46 to the lower member 20 as by bolts 16. Shunt member 46 is coextensive with lower repeller member 32 attached as shown to the frame 18 which is at ground potential.
  • a shunt member 46 e.g. a copper strip
  • This structural arrangement effectively directs or shunts the lines of force from corotron 14 to ground thus preventing any ambient toner dust from spreading.outwardly away from the brush area 42 overcoming the dusting problem.
  • optical density of the print is enhanced by the concentration of toner adjacent the printing area on drum 10.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Dry Development In Electrophotography (AREA)
  • Magnetic Brush Developing In Electrophotography (AREA)
  • Cleaning In Electrography (AREA)
  • Control Or Security For Electrophotography (AREA)
EP84114583A 1983-11-30 1984-11-30 Dispositif électrostatique pour repousser le toneur dans une machine électrophotographique Ceased EP0146825A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US55652983A 1983-11-30 1983-11-30
US556529 1983-11-30

Publications (2)

Publication Number Publication Date
EP0146825A2 true EP0146825A2 (fr) 1985-07-03
EP0146825A3 EP0146825A3 (fr) 1986-12-30

Family

ID=24221727

Family Applications (1)

Application Number Title Priority Date Filing Date
EP84114583A Ceased EP0146825A3 (fr) 1983-11-30 1984-11-30 Dispositif électrostatique pour repousser le toneur dans une machine électrophotographique

Country Status (4)

Country Link
EP (1) EP0146825A3 (fr)
JP (1) JPS61500568A (fr)
CA (1) CA1229373A (fr)
WO (1) WO1985002471A1 (fr)

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2987660A (en) * 1955-06-06 1961-06-06 Haloid Xerox Inc Xerographic charging
US3937570A (en) * 1971-06-03 1976-02-10 Xerox Corporation Cloud suppression in an electrostatic copying apparatus
US4168901A (en) * 1975-01-21 1979-09-25 Canon Kabushiki Kaisha Developer housing sealing device for electrophotography
DE2816621C3 (de) * 1978-04-17 1980-10-09 Lumoprint Zindler Kg (Gmbh & Co), 2000 Hamburg Dichtungsanordnung in einer Entwicklungsvorrichtung eines Kopiergeräte
US4338880A (en) * 1978-09-19 1982-07-13 Minolta Camera Kabushiki Kaisha Magnetic brush development apparatus for use in electrophotographic copying machine
JPS5664365A (en) * 1979-10-30 1981-06-01 Ricoh Co Ltd Developing device
US4387982A (en) * 1981-07-01 1983-06-14 Xerox Corporation Charged particle containment apparatus
US4697914A (en) * 1982-06-30 1987-10-06 Xerox Corporation Toner containment method and apparatus

Also Published As

Publication number Publication date
JPH0222950B2 (fr) 1990-05-22
CA1229373A (fr) 1987-11-17
EP0146825A3 (fr) 1986-12-30
JPS61500568A (ja) 1986-03-27
WO1985002471A1 (fr) 1985-06-06

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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Effective date: 19860103

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Owner name: UNISYS CORPORATION

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Effective date: 19871217

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18R Application refused

Effective date: 19890211

RIN1 Information on inventor provided before grant (corrected)

Inventor name: FEDDER, RICHARD C.

Inventor name: KASU, ABDULLATIF M.

Inventor name: THOMPSON, AUBREY E.

Inventor name: ROBSON THOMAS