US3448356A - Electrostatic copyholder and method for making same - Google Patents

Electrostatic copyholder and method for making same Download PDF

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Publication number
US3448356A
US3448356A US552483A US3448356DA US3448356A US 3448356 A US3448356 A US 3448356A US 552483 A US552483 A US 552483A US 3448356D A US3448356D A US 3448356DA US 3448356 A US3448356 A US 3448356A
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United States
Prior art keywords
conductive
grid
electrostatic
stripes
panel
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Expired - Lifetime
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US552483A
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English (en)
Inventor
Anthony Q Testone
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Simco Co Inc
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Simco Co Inc
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B27/00—Photographic printing apparatus
    • G03B27/32—Projection printing apparatus, e.g. enlarger, copying camera
    • G03B27/52—Details
    • G03B27/62—Holders for the original
    • G03B27/6207—Holders for the original in copying cameras
    • G03B27/6214—Copy boards
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B27/00—Photographic printing apparatus
    • G03B27/02—Exposure apparatus for contact printing

Definitions

  • This invention relates to an improved electrostatic copyboard for retaining articles in position by electrostatic force preparatory to photographing or other operations, and more particularly relates to a method for fabricating such a copyboard.
  • I F is the force of electrostatic attraction (or repulsion) between the charged bodies
  • the present invention relies on the principles of Coulombs Inverse Square Law in its application to nonconductive objects and, in addition, upon the fact that, within its shape limitations, a conductive body (or one rendered conductive by virtue of a Water film) tends to orient itself parallel to the lines of force of an electric field.
  • the conductive body endeavors also to move perpendicular to and in the direction of the most concentrated or densest electrical field.
  • the electrostatic holding device of the instant invention depends upon the creation of a plurality of charged condensers whose plates are so oriented that the lines of force of their electrical field are densest just below the surface of the board and in a direction parallel thereto while at the same time projecting a plurality of arcuate field patterns above the surface.
  • the surface of the board is also fabricated to have an optimum effective area of non-conductive construction upon which electrostatic charges of a given polarity may be imposed for attracting and efiiciently retaining non-conductive articles and sheets.
  • Another object of this invention is to provide an electrostatic copyholder in which a plurality of discrete electric field mosaics are formed by a grid construction defining a multiplicity of condensers within the surface of the copyholder while at the same time establishing a dielectric surface upon which electrical charges may be imposed.
  • Still another object of this invention is to provide a method for making an electrostatic copyboard which will accomplish the condenser-charged surface configuration by a painted-on grid arrangement.
  • Yet another object of this invention is to provide a method for making a grid-type electrostatic copyholder utilizing techniques which are simply effectuated.
  • FIGURE 1 is a perspective view of a new and improved electrostatic copyboard embodying this invention.
  • FIGURE 2 is a sectional view taken along lines 22 of FIGURE 1.
  • FIGURE 3 is a sectional view taken along lines 3-3 of FIGURE 2.
  • FIGURE 4 is a sectional view taken along lines 4-4 of FIGURE 3.
  • FIGURE 5 is a perspective view of a conductive grid configuration applied to the rear surface of dielectric panel embodied in this invention.
  • FIGURE 6 is a perspective view of a conductive grid configuration applied to the front surface of the dielectric panel.
  • FIGURE 7 is a fragmentry perspective view of the copyboard showing the electric field of force in broken lines.
  • an electrostatic copyholder generally designated as A
  • B a sheet or sheets of design material
  • the copyholder A comprises a stiff flat insulative base plate 12 to whose front face is adhesively secured a grid panel C.
  • the base plate 12 may be made of wood but is preferably fabricated of a pressed fiber-board wood composition, such as tempered masonite, which is plastic coated on both sides for waterproofing and anti-warping.
  • the base board 12 may be /2 inch thick for suitable subjacent support and can have dimensions which are rectangular and/or suitable for the needs of a particular customer.
  • the insulating panel 14 is preferably a polyester film, such as Mylar, and IO-mil (.010 inch) Mylar has been determined to have excellent dielectric characteristics for this purpose.
  • the film panel 14 is secured to the surface of board 12 with a doublebacked adhesive tape interfacial arrangement at 13, such as Permacel #02 tape, which is a 2 mil rope-paper backing coated on both sides with a solvent resistant adhesive.
  • the grid panel C is adhesively secured to the insulating film 14 by a second layer 15 of doublefaced adhesive tape.
  • the grid panel C is also fabricated of l0-mil Mylar polyester film and has identical dimensional configuration as both the backboard 12 and the film 14.
  • a conductive pattern 20 which, in the case of a rectangular board A, has the shape of a rectangular border 18 enclosing a plurality of diagonally arranged stripes 22 therein.
  • the border 18 is spaced from the periphery of the panel C by a clear margin 19 approximately 1 /2 inches in width since high voltage will he applied to pattern 20.
  • the border 18 may be one inch wide all the way around, and the stripes 22 themselves may be /2 inch wide and spaced uniformly from each other by clear zones or nonpainted stripes 21.
  • the entire pattern .20 may be incorporated by using a stencil and painting or rolling a conductive coating, such as Butens No. 13976 conductive paint, through the stencil. It is important to note that the stripes 21-22 on the back surface are arranged diagonally. However, while the configuration shown is at a 45 angle from the base, other inclinations varying from 30 to 60 from the base may also be satisfactory. In this regard, the angular disposition of the stripes 22 is only significant in its relation to the configuration of the stripes 32 on conductive pattern 30 on the opposite face of the grid panel C.
  • the conductive grid pattern 30 on the front face of panel C is also a geometric configuration and includes an identical conductive coating such as that on the rear surface. See FIGURE 6. In this case, however, the ground side of a DC. high voltage generator source G is applied so that the border 28 may extend directly to the periphery of the panel.
  • the conductive stripes or bands 32 are disposed vertically with alternate longitudinally extending clear areas 31 intermediate adjacent bands.
  • the border 28 is approximately one inch in width about the periphery, and the stripes 32 and clear zone 31 may each be /2-inch Wide. It is Worth mentioning again that the orientation of the stripes 32 with respect to the stripes '22 may be reversed so that the front pattern 30 may have diagonal bands whereas the rear pattern could have vertically or horizontally-disposed bands.
  • a metal flathead screw 24- is mounted in the lower right hand corner of the base board 12 and has a head which is in abutment with and directly connected to the border 18 of the high voltage grid pattern 20.
  • a blob of conductive cement 2-5 is used to adhesively secure the screwhead 24 in firm electrical contact with the high voltage pattern 20.
  • a terminal 26 is coupled to the rear portion of the screw 24 and extends downwardly within a bore 27 in the base plate 12.
  • a male connector 34 is formed on the end of wire conductor .35 running through shielded cable D and is received within the bore 27 for engaging the female terminal 26.
  • the lead 35 is connected to the high voltage side of the DC. generator G.
  • the low voltage or ground side of the DC. generator G is connected to the shielding braid 37 which surrounds the insulation of cable D.
  • the grounded shielding braid 37 is connected to binding post portion 38 at the rear of flathead screw 40.
  • the shank of the screw 40 passes through the clear margin 19 about pattern 20, and the underside of the screwhead 40 cemented at 39 With a blob of conductive adhesive to the border 28 of pattern 30.
  • the patterns 20 and 30' are spaced from each other by dielectric film C of Mylar so that when the DC. high voltage is applied thereacross, the
  • the entire front face of the panel C, the peripheral edges of the base plate 12 and its rear marginal surface is then encapsulated with a polyvinyl fluoride shrink film 42, such as Tedlar.
  • the shrink film 42 thus seals the edges of the board A and protects the exterior conductive pattern 30 by covering it.
  • the edges of the board A are framed with a bezel 44 made of extruded polyvinyl chloride moldings which are mitered together and secured to the 'base plate 12 with finishing screws 46.
  • a cover sheet 48 is hung from the upper edge of the copyboard A across the face thereof and acts as the active working surface.
  • the cover sheet 48 is insulative in character and may be a fiber glass calendered sheet which is impregnated with silicon rubber.
  • the high voltage generator G is a conventional D.C. electrostatic power source which can develop a DC. potential in the range 5,00015,000 volts.
  • the generator G is shown in block form and for purposes of the present invention develops a positive output when switch 50 is closed. Accordingly, a positive voltage will be imposed on the grid pattern 20 whereas the grid pattern 30 wil1 be at ground or negative. In this case, abutting a nonconductive sheet B against the face of the copyboard A, i.e. on cover shade 48, will cause the non-conductive sheet B to stick with a fair degree of attraction by virtue of polarization.
  • the sheet B will pick up negative charges from ground.
  • the net negative charge on the nonconductive sheet will cause it to be strongly attracted toward the positively charged grid pattern 20, especially Where the clear areas 31 overlie a conductive stripe 22.
  • the sheet B were rendered conductive by a water film or if it were already a conductor as in the case of a metal foil, or even very slightly conductive, as for example, paper with about 5% moisture content, it would now be drawn by the arcuate fringe field or edge leakage lines of force which would extend from the stripes 22 through the clear areas 21 and 31 and back in an arcuate pattern to the stripes 32. These lines of force are demonstrated in broken lines in FIGURE 7.
  • the field is most dense where the plates or stripes 22 and 32 overlie one another. However, these fields of maximum density do not penetrate beyond the overlying ground pattern, and are therefore not effective in attracting conductive objects.
  • edges of the fields of the multiplicity of small condensers are effective to form fringe lines of force which, though of a lesser intensity, do extend beyond the surface of the cover sheet 48 and are most efiicient in drawing down conductive or even slightly conductive objects toward the field of maximum concentration, and pulling them down from a short distance.
  • the present copyboard as did that of prior Patent No. 3,359,469, also permits a renewal of the charge by switching of the power supply G.
  • the use of the switching arrangement (reversal of the polarity of voltage applied to the board) to accommodate diminution of attractive force is of even more importance with regard to the securing of conductive sheets B. That is, since thesheets B are, by definition, conductive, the surface charge is drawn oif the board much more rapidly than is the case of non-conductive sheets. Accordingly, switching must be performed between each successive application of conductive sheets rather than after a plurality of applications of non-conductive sheets which causes attrition.
  • the arcuate field pattern would draw down the conductive sheet B.
  • the sheet B is further rubbed by the grounded operators hand, the sheet would immediately acquire a negative charge (from ground).
  • the conductive sheet is removed from the board, its negative charge is partially left behind upon the surface of the board to counterbalance the positive polarized charge on the boards surface. As a consequence, the whole surface of the board is effectively at ground potential and hence inoperative.
  • the board is once more prepared to attract conductive sheets by virtue of the alternately established arcuate or secondary field.
  • the board A is also prepared to hold non-conductive materials because of the negative voltage on the parts mentioned and act in the manner described in the prior application, Ser. No. 362,049.
  • Still another mode of securing a maximum staggering of the condenser plates would be by a pair of checkerboard patterns whose conductive squares are arranged to overlie clear squares in the superimposed pattern.
  • An electrostatic copyholder comprising a rigid insulative board, a dielectric panel secured to one face of said board, a first conductive grid intermediate the board and said panel, a second conductive grid on the opposite face of said dielectric panel and having a pattern of spaced apart conductive elements overlying said first grid and insulated therefrom, an insulative cover secured over the surface of said second conductive grid, and means for connecting a DO.
  • first and second grids being so constructed and arranged with respect to each other that the electrical field between the two grids will emanate edge fringe lines passing beyond said cover in an arcuate spray, whereby nonconductive articles placed in abutment with said cover will electrostatically adhere thereto by virtue of charges induced in said articles opposite in polarity to those on said cover produced by said high voltage means, and conductive articles juxtaposed with said cover will adhere thereto by virtue of the edge fringe lines of said field.
  • first and second grids each comprise a plurality of stripes and the stripes of the first grid being obliquely oriented with respect to the stripes on said second grid.
  • each of said grids comprises a painted-on conductive coating.
  • the means for connecting the high voltage across said first and second grids comprises a terminal having a flat head connected to the border of said first grid, and a second terminal passing through the marginal portion about the border of said first grid and having a fiat head connected to the border of said second grid.
  • An electrostatic copyholder comprising a rigid insulative board, a dielectric panel secured to one face of said board, a first conductive member intermediate the board and said panel, a second conductive member constituting a grid on the opposite face of said dielectric panel and having a pattern of spaced apart conductive elements with interstices there'between, an insulative cover secured over the surface of said second conductive member, and means for connecting a DC.
  • first and second conductive members being so constructed and arranged that the electrical field created therebetween will emanate edge fringe lines passing beyond said cover in an arcuate spray, whereby non-conductive articles placed in abutment with said cover will electrostatically adhere thereto by virtue of charges induced in said articles opposite in polarity to those on said cover produced by said high voltage means, and conductive articles juxtaposed with said cover will adhere thereto by virtue of the edge fringe lines from said field passing through the interstices of said grid.
  • said first conductive member constitutes a grid having a pattern of spaced apart conductive elements and said first and second grids each comprises a plurality of stripes with the stripes of said first grid being obliquely oriented with respect to the stripes on said second grid.
  • An electrostatic copyholder comprising a dielectric panel, a first conductive member overlying one face of said dielectric panel, a second conductive member constituting a grid overlying the second face of said dielectric panel and having spaced apart open areas between conductive portions, and means for connecting a DC.
  • first and second conductive members being so constructed and arranged that the electrical field created therebetween will emanate edge fringe lines passing through the open areas and beyond the grid in an arcuate spray, whereby conductive articles juxtaposed upon the second face will adhere thereto by virtue of the electrical field between said conductive members emanating through the open areas of said second conductive member, and non-conductive articles will adhere to the second face by virtue of charges induced in said non-conductive articles opposite in polarity to those of said second face produced by said D.C. high voltage.
  • the invention of claim 12 including an insulative sheet covering said second conductive member.
  • An electrostatic copyboard comprising a first conductive member, a second conductive member constituting a grid having spaced apart open areas between conductive portions, a dielectric panel interposed between said first and second conductive members, and means for connecting a DC high voltage across said first and second conductive members, said first and second conductive members being so constructed and arranged with respect References Cited UNITED STATES PATENTS 3,194,131 7/1965 Robinson. 3,337,784 8/1967 Lueder 317-262 LEE T. HIX, Primary Examiner.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Elimination Of Static Electricity (AREA)
  • Exposure Or Original Feeding In Electrophotography (AREA)
  • Paper (AREA)
US552483A 1966-05-24 1966-05-24 Electrostatic copyholder and method for making same Expired - Lifetime US3448356A (en)

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US55248366A 1966-05-24 1966-05-24

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US (1) US3448356A (enrdf_load_html_response)
BE (1) BE697811A (enrdf_load_html_response)
CH (1) CH475575A (enrdf_load_html_response)
GB (1) GB1177688A (enrdf_load_html_response)
NL (1) NL150966B (enrdf_load_html_response)
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Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3571678A (en) * 1967-09-04 1971-03-23 Watanabe Instr Electrostatic recording paper holding device
US3634740A (en) * 1970-04-20 1972-01-11 Addressograph Multigraph Electrostatic holddown
US4113380A (en) * 1976-08-27 1978-09-12 Agfa-Gevaert Ag Feeding and electrostatic holding originals in a copying machine
US4234621A (en) * 1979-01-08 1980-11-18 Fieux Robert E Means and method of restoring documents, paintings and the like
US5229910A (en) * 1990-10-02 1993-07-20 Abisare Co., Ltd. Billboard device
US5442429A (en) * 1992-09-30 1995-08-15 Tr Systems Inc Precuring apparatus and method for reducing voltage required to electrostatically material to an arcuate surface
US5486974A (en) * 1992-12-03 1996-01-23 Abisare Co., Ltd. Electrostatic attraction board system
US5508086A (en) * 1992-07-29 1996-04-16 Abisare, Co., Ltd. Electrostatic notice board system
US20050231577A1 (en) * 2004-04-14 2005-10-20 Mcnally Stephen Capacitive mat control
US20110198299A1 (en) * 2008-10-28 2011-08-18 Gideon Rosenberg Purification sheet assembly combining flow obstacles and electric field formation

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3129452B2 (ja) * 1990-03-13 2001-01-29 富士電機株式会社 静電チャック
GB201518961D0 (en) * 2015-10-27 2015-12-09 Js Design Pro Ltd Improvements in drawings boards

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3194131A (en) * 1962-10-09 1965-07-13 Eastman Kodak Co Document copiers
US3337784A (en) * 1962-02-09 1967-08-22 Lueder Holger Method for the production of unipolar ions in the air and for enriching the air of a room with them

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3337784A (en) * 1962-02-09 1967-08-22 Lueder Holger Method for the production of unipolar ions in the air and for enriching the air of a room with them
US3194131A (en) * 1962-10-09 1965-07-13 Eastman Kodak Co Document copiers

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3571678A (en) * 1967-09-04 1971-03-23 Watanabe Instr Electrostatic recording paper holding device
US3634740A (en) * 1970-04-20 1972-01-11 Addressograph Multigraph Electrostatic holddown
US4113380A (en) * 1976-08-27 1978-09-12 Agfa-Gevaert Ag Feeding and electrostatic holding originals in a copying machine
US4234621A (en) * 1979-01-08 1980-11-18 Fieux Robert E Means and method of restoring documents, paintings and the like
US5229910A (en) * 1990-10-02 1993-07-20 Abisare Co., Ltd. Billboard device
US5508086A (en) * 1992-07-29 1996-04-16 Abisare, Co., Ltd. Electrostatic notice board system
US5442429A (en) * 1992-09-30 1995-08-15 Tr Systems Inc Precuring apparatus and method for reducing voltage required to electrostatically material to an arcuate surface
US5486974A (en) * 1992-12-03 1996-01-23 Abisare Co., Ltd. Electrostatic attraction board system
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
US20110198299A1 (en) * 2008-10-28 2011-08-18 Gideon Rosenberg Purification sheet assembly combining flow obstacles and electric field formation

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BE697811A (enrdf_load_html_response) 1967-10-02
GB1177688A (en) 1970-01-14
NL150966B (nl) 1976-09-15
SE329330B (enrdf_load_html_response) 1970-10-05
CH475575A (de) 1969-07-15
NL6707182A (enrdf_load_html_response) 1967-11-27
DE1654729A1 (de) 1972-03-16

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