US3851962A - Electrostatic hold down apparatus - Google Patents

Electrostatic hold down apparatus Download PDF

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Publication number
US3851962A
US3851962A US00392746A US39274673A US3851962A US 3851962 A US3851962 A US 3851962A US 00392746 A US00392746 A US 00392746A US 39274673 A US39274673 A US 39274673A US 3851962 A US3851962 A US 3851962A
Authority
US
United States
Prior art keywords
drum
paper
sheet
plate
electrode
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
US00392746A
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English (en)
Inventor
Vloten C Van
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.)
Savin Business Machines Corp
Original Assignee
Savin Business Machines 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 Savin Business Machines Corp filed Critical Savin Business Machines Corp
Priority to US00392746A priority Critical patent/US3851962A/en
Priority to DE2439440A priority patent/DE2439440A1/de
Priority to JP49098445A priority patent/JPS5051741A/ja
Application granted granted Critical
Publication of US3851962A publication Critical patent/US3851962A/en
Anticipated expiration legal-status Critical
Expired - Lifetime 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
    • G03G15/14—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base
    • G03G15/16—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base of a toner pattern, e.g. a powder pattern, e.g. magnetic transfer
    • G03G15/163—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base of a toner pattern, e.g. a powder pattern, e.g. magnetic transfer using the force produced by an electrostatic transfer field formed between the second base and the electrographic recording member, e.g. transfer through an air gap
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G2215/00—Apparatus for electrophotographic processes
    • G03G2215/16—Transferring device, details
    • G03G2215/1604—Main transfer electrode
    • G03G2215/1633—Plate
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S271/00—Sheet feeding or delivering
    • Y10S271/901—Magnetic operation

Definitions

  • ABSTRACT Electrostatic hold down apparatus for effecting transfer of a tacky toner image from the photoconductivc surface of a drum to a sheet of paper or the like for which the toner has greater affinity than for the drum surface in which the paper is brought to the same potential as a plate extending over an area of and in closely spaced relationship to the drum surface as the paper enters the space between the plate and the drum with the plate being placed at a relatively high negative potential with respect to the drum to cause electrostatic forces to bring the portion of the paper beneath the plate into intimate contact with the drum surface.
  • the electrostatic hold down force is relieved so that the paper is easily stripped from the drum and the image, owing to the greater affinity of the tacky toner for the paper, leaves the drum with the paper.
  • Light reflected from the specimen to be copied is projected onto the surface of the drum to render it conductive in non image areas to permit charge to leak off in the area of exposure and thus to leave a latent electrostatic image of the specimen upon the drums surface.
  • the image is developed by rotating the drum through a suspension of toner and carrier particles wherein the frictional interactionbetween these two developer components has caused the toner particles to acquire charges opposite to those on the drums surface.
  • the oppositely charged toner particles adhere to the drum in those areas defined by the latent electrostatic image while the. like-charged carrier particles remain in the developer suspension.
  • the developed image is transferred from the drums surface to the sheet material.
  • a secondcorona discharge is used to charge the latter which is brought into close proximity with the former whereupon the charged toner image is electrostatically transferred to the surface of the sheet material.
  • the final image is made permanent by a critically controlled heating of the sheet material to a temperature sufficient to fix the image without burning or discoloring the sheet material.
  • mere application of the sheet material to the'drums surface under pressure effects image transfer.
  • the pressure necessary to achieve image transfer in Smith et al. is applied by a roller which presses the sheet material against the drum.
  • the roller successfully achieves image transfer without the use of an auxiliary image transfer system it incorporates a number of defects.
  • the roller has limited area contact with the drum producing nearly line contact which may allow slippage between paper and drum.
  • a misfed piece of paper or operation of the machine without paper may cause direct contact between roller and drum necessitating cleaning of the roller and possibly damaging the drum.
  • My invention avoids these disadvantages.
  • FIG. 1 is a perspective view of my electrostatic hold down apparatus"
  • FIG. 2 is a side elevation of the electrostatic hold down apparatus shown in FIG. 1.
  • the surface of a drum 10, forming part of an electrostatic copier, and adapted to be driven by any suitable means (not shown) carries a photoconductive coating 12 adapted to receive a latent electrostatic image which is developed, for example, with a developer comprising tacky toner particles suspended in a diluent in the manner described in the Smith et al. application, supra.
  • My hold down apparatus includes an arcuate conductive plate 14 mounted parallel to and in close proximity to the surface of drum 12 to form a paper passage 16 between drum 10 and plate 14.
  • a lip 18 extending along the lower edge of plate 14 forms a mouth 20 opening into passage 16.
  • Any suitable means such as screws 22 or the like secure a wide conductive brush 24 to, and in electrical contact with, the lip 18 so that the brush extends across mouth 20 toward the surface 12 of the drum 10.
  • An elongated wedge-shaped guide 26 positioned below mouth 20 directs the leading edgeof a length of paper 28 into engagement with brush 24 as it enters mouth 20.
  • a brush 30 in engagement with drum l0 maintains the drum at ground potential.
  • My apparatus includes a power supply 32 of any suitable type known to the art which produces an output potential of minus 2 to 3 Kv. I connect the negative output terminal to plate 14 to place the plate and brush 24 at a potential of the order of minus '2-3 Kv with respect to the grounded drum l0. 1 may provide my apparatus with a guide 34 for assisting in stripping the paper 28 from the drum 10.
  • the hold down force is computed by F Eq where E is the intensity of the electrostatic field between the plate 14 and drum l0 and q is the charge on the paper 28. Sufficient force is generated to cause transfer of the tacky toner image from the drums surface to the paper unassisted by any external mechanical means such as pressure rollers. In an experimental set up with a plate at minus 3 Kv a hold down force of approximately 14 oz/in was produced. Once the paper exits from the electrostatic field in the transfer area, the
  • hold down force is substantially reduced thereby facilitating removal of the paper from the drum by guide 34, for example.
  • an elongated brush 24 I might employ a plurality of wire brushes, for example.
  • means other than a drum may be used for forming a toner image and applying it to a contacting sheet of paper, such as a belt-like apparatus.
  • My apparatus produces intimate contact between paper and drum with force sufficient to transfer a toner image without the use of mechanical means such as pressure rollers. In addition, contact is achieved over a broad area of the drum and paper surfaces simultaneously.
  • apparatus for electrostatically holding said sheet of copy material in contact with said surface at said transfer station including a plate-like electrode of conductive material, means mounting said electrode at said transfer station in closely spaced relationship to said surface to form a passage having an entrance into which said sheet is introduced and-an exit from which said sheet emerges in the course of a transfer operation, a source of potential, means for applying said potential to said electrode to produce a static electrical field in said passage, and means for applying said potential directly to said sheet as it moves into said entrance.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Electrostatic Charge, Transfer And Separation In Electrography (AREA)
  • Paper Feeding For Electrophotography (AREA)
US00392746A 1973-08-29 1973-08-29 Electrostatic hold down apparatus Expired - Lifetime US3851962A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US00392746A US3851962A (en) 1973-08-29 1973-08-29 Electrostatic hold down apparatus
DE2439440A DE2439440A1 (de) 1973-08-29 1974-08-16 Uebertragungseinrichtung zum uebertragen eines elektrostatischen bildes
JP49098445A JPS5051741A (enrdf_load_stackoverflow) 1973-08-29 1974-08-29

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US00392746A US3851962A (en) 1973-08-29 1973-08-29 Electrostatic hold down apparatus

Publications (1)

Publication Number Publication Date
US3851962A true US3851962A (en) 1974-12-03

Family

ID=23551852

Family Applications (1)

Application Number Title Priority Date Filing Date
US00392746A Expired - Lifetime US3851962A (en) 1973-08-29 1973-08-29 Electrostatic hold down apparatus

Country Status (3)

Country Link
US (1) US3851962A (enrdf_load_stackoverflow)
JP (1) JPS5051741A (enrdf_load_stackoverflow)
DE (1) DE2439440A1 (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040212146A1 (en) * 2000-07-12 2004-10-28 Peter Wulf Device for guiding sheets
US20050231577A1 (en) * 2004-04-14 2005-10-20 Mcnally Stephen Capacitive mat control
US20080048381A1 (en) * 2006-05-15 2008-02-28 Hunkeler Ag Gathering device

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2754580B2 (ja) * 1988-07-29 1998-05-20 ミノルタ株式会社 クリーナ

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3146385A (en) * 1960-12-09 1964-08-25 Xerox Corp Xerographic plate charging method and apparatus
US3240933A (en) * 1962-11-26 1966-03-15 Dow Corning Electrostatic treatment of silicone release coatings
US3405052A (en) * 1964-08-26 1968-10-08 Grace W R & Co Apparatus for corona treatment of film including a porous sintered metal electrode
US3578859A (en) * 1969-07-03 1971-05-18 Xerox Corp Mechanical stripping apparatus
US3620617A (en) * 1969-11-24 1971-11-16 Ibm Electrophotographic apparatus with improved toner transfer
US3649262A (en) * 1968-12-31 1972-03-14 Xerox Corp Simultaneous development-cleaning of the same area of an electrostatographic image support surface

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3146385A (en) * 1960-12-09 1964-08-25 Xerox Corp Xerographic plate charging method and apparatus
US3240933A (en) * 1962-11-26 1966-03-15 Dow Corning Electrostatic treatment of silicone release coatings
US3405052A (en) * 1964-08-26 1968-10-08 Grace W R & Co Apparatus for corona treatment of film including a porous sintered metal electrode
US3649262A (en) * 1968-12-31 1972-03-14 Xerox Corp Simultaneous development-cleaning of the same area of an electrostatographic image support surface
US3578859A (en) * 1969-07-03 1971-05-18 Xerox Corp Mechanical stripping apparatus
US3620617A (en) * 1969-11-24 1971-11-16 Ibm Electrophotographic apparatus with improved toner transfer

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040212146A1 (en) * 2000-07-12 2004-10-28 Peter Wulf Device for guiding sheets
US7328899B2 (en) * 2000-07-12 2008-02-12 Man Roland Druckmaschinen Ag Device for guiding sheets
US20050231577A1 (en) * 2004-04-14 2005-10-20 Mcnally Stephen Capacitive mat control
US7008129B2 (en) 2004-04-14 2006-03-07 Hewlett-Packard Development Company, Lp. Capacitive mat control
US20080048381A1 (en) * 2006-05-15 2008-02-28 Hunkeler Ag Gathering device
US7618040B2 (en) * 2006-05-15 2009-11-17 Hunkeler Ag Gathering device

Also Published As

Publication number Publication date
DE2439440A1 (de) 1975-03-06
JPS5051741A (enrdf_load_stackoverflow) 1975-05-08

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