US3670203A - Method of and apparatus for imparting an electrical charge to a web of film or paper or the like - Google Patents

Method of and apparatus for imparting an electrical charge to a web of film or paper or the like Download PDF

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Publication number
US3670203A
US3670203A US29816A US3670203DA US3670203A US 3670203 A US3670203 A US 3670203A US 29816 A US29816 A US 29816A US 3670203D A US3670203D A US 3670203DA US 3670203 A US3670203 A US 3670203A
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United States
Prior art keywords
web
conductive
roller
electrical charge
conductive means
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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
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US29816A
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English (en)
Inventor
Thomas C Whitmore Jr
Robert G Cunningham
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Eastman Kodak Co
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Eastman Kodak Co
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Publication date
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Publication of US3670203A publication Critical patent/US3670203A/en
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    • 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
    • G03G15/02—Apparatus for electrographic processes using a charge pattern for laying down a uniform charge, e.g. for sensitising; Corona discharge devices
    • G03G15/0266—Arrangements for controlling the amount of charge
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05F—STATIC ELECTRICITY; NATURALLY-OCCURRING ELECTRICITY
    • H05F3/00—Carrying-off electrostatic charges
    • H05F3/04—Carrying-off electrostatic charges by means of spark gaps or other discharge devices

Definitions

  • ABSTRACT An electrical charge is applied to a moving web of flexible material such as film or paper by transporting the web over a grounded roller while maintaining a stationary electrically charged plate adjacent to the web but spaced slightly therefrom.
  • a direct current voltage of the required sign and magnitude is applied to the plate from any suitable source such as a generator or battery. Alternatively the plate can be grounded and the voltage applied to the roller.
  • the present invention relates to a method and apparatus for applying an electrical charge to a moving web of flexible material such as a continuous web of photographic paper or film.
  • the latter roller is preferably covered with a semi-conductive material which is sufficiently conductive for charge application, but which will not generate sparks if the two rollers come together when a web breaks or runs out.
  • a semi-conductive material which is sufficiently conductive for charge application, but which will not generate sparks if the two rollers come together when a web breaks or runs out.
  • One-of the covering materials for this roller is a plush fabric which has been treated with a surfactant to make it partially conductive.
  • Our apparatus has proved to operate very effectively without scratching a web and without generating sparks.
  • the plush fabric is apt to become contaminated with dust, or with other contaminants which may be imparted to the web. Such contamination is particularly disadvantageous when processing photographic film or paper through some steps in the production process, such as emulsion coating operations.
  • One of the electrically conductive bodies is connected to ground and the other is connected to a source of a direct cur rent voltage of sufficient magnitude to pass across the gap between the web and the second conductive member but without developing a corona discharge.
  • the voltage should be of such magnitude and sign as to develop a desired electrical charge condition on the web, for example, neutral, or positively or negatively charged.
  • a web in another mode of operation, can be precharged to a selected voltage by our method at one station in a production line, and subsequently, after intermediate processing steps, can again be treated by our method to neutralize the charge on the sheet which may or may not have picked up additional charge.
  • FIG. 1 is a schematic side elevational view showing one form of apparatus for developing a desired electrical charge condition on a long continuous web of flexible material, such as photographic film or paper which is bent around a roller; and
  • FIG. 2 is a schematic side elevational view showing a modified form of apparatus for treating a web moving in a straight line.
  • FIG. 1 of the drawings a long continuous web 11 of photographic film or paper is transported continuously in contact with an electrically conductive roller 13 which is connected to ground.
  • Shoe 15 and roller 13 can be made of an electrically conductive material such as brass or other metal; or may be made of a normally non-conductive material such as synthetic resin which has been made conductive by impregnation with a surfactant such as asodium salt of an alkylaryl polyether sulfonate, or coated with a metal such as silver.
  • a suitable variable power supply or source 19 of a direct current voltage is connected to the shoe 15 and is provided with voltage sign and magnitude adjusters 21 and 23 for applying the correct voltage to the shoe. Any source can be employed, such as batteries, or a DC. generator, or a rectifier connected to an A.C. power line.
  • the voltage applied to the shoe 15 should have the same sign as the charge on the web; to increase charge on the web without changing its sign, the voltage applied to the shoe should have the opposite sign. (The change in potential on the web is of opposite sign to the potential applied to the shoe.)
  • an electrostatic field meter 25 adjacent to the web 11 after it has passed shoe 15, so as to continuously measure or monitor the electrostatic field resulting from any electrical charge on the web, and to display it on a meter 27.
  • the operator observes the voltage and its sign on the meter 27, and adjusts the voltage supply 19 as needed so as to assure the correct charge and sign.
  • An electrostatic field meter suitable for this purpose is described in the July, 1950 issue of the Journal of the Society of Motion Picture and Television Engineers" in an article by H.W. Cleveland on pages 37-44 entitled, A Method of Measuring Electrification of Motion Picture Film Applied to Cleaning Operations.”
  • the charge which has built up on a web 11 of photographic material may be quite large, resulting in electrostatic potentials of anywhere from 100 to 50,000 volts.
  • the charge may have a positive or negative sign, depending upon the nature of the web material, and of the rollers or other apparatus through or over which it has been passing.
  • the applied voltage to neutralize normally is about the same or greater than the potential on the web if the spacing is 1 mm or more between the shoe and the web.
  • the magnitude of the voltage applied depends upon the desired charge on the web, and can be varied as desired. Anywhere between volts and as high as 10,000 or even 30,000 volts may be applied as needed.
  • the types of web materials that can be treated by the invention are many and varied, such as cellulose triacetate film base or poly(ethylene terephthalate) film base or other polyester film bases, which may or may not have been coated with sensitized emulsions, subbing layers, or antihalation backing layers.
  • 'Other webs can be formed of photographic paper which may or may not have coatings of photosensitive emulsions, polyethylene or the like.
  • Our novel method operates effectively when the web material is electrically non-conductive, is in a dry condition, and is of constant thickness beforeand after passing between the roller 13 and plate 15 (without a liquid or semi-liquid layer thereon).
  • the roller 13 can be an idler roller, with the web 11 being transported by motor driven rollers located elsewhere.
  • roller 13' the variable power supply 19, the field meter and the voltage indicator 27, are all the same as described in connection with FIG. 1.
  • a web 11' is passing straight through during a processing operation in contact with a series of rollers 13', 31 and 33, with each roller developing additional static charge on the web.
  • this static charge can become so large as to cause serious sparking if the web is subsequently grounded.
  • Such sparking can have serious effects not only on the web itself but also on the photographic film or paper which is exposed to the action of light from the sparks.
  • the meter 25 can be used to measure the charge at a point past the rollers, and the voltage can then be applied to the plate 15 to neutralize the static charge so as to prevent detrimental efiects.
  • Spark discharges are prevented when a web of photographic material is grounded, thus avoiding spark damage to the sheet itself, and avoiding the exposure of other photographic materials in the same darkroom.
  • first electrically conductive means of said transport system for supporting one surface of the web
  • second electrically conductive means spaced from said first conductive means and between which the web is transported by said web transporting means; I means for grounding one of said first and second conductive means;
  • adjustable means for applying a direct current voltage of a selected magnitude and sign to the other of said first and of one or second conductive means for generating an electrostatic field without generating a corona discharge; 7 means adjacent said first and second conductive means for monitoring the electrical charge on the web; and
  • said first conductive means comprises a roller
  • said second conductive means comprises an arcuate plate having a surface concentric with and spaced from said roller.
  • said first conductive means comprises a grounded roller
  • said second conductive means comprises an arcuate plate having a surface concentric with and spaced from said roller and electrically connected to said adjustable direct current voltage applying means
  • said monitoring means is positioned to monitor the charge on the web after it leaves the roller.
  • a method of developing a predetermined electrical charge condition on a flexible light-sensitive web material transported over a transport system of one or more conducting rollers comprising the steps of:
  • first and second conductive members transporting the web through opposed, spaced apart first and second conductive members, one of which is grounded, and one of which is engaged by one side of the web;

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • General Physics & Mathematics (AREA)
  • Elimination Of Static Electricity (AREA)
  • Delivering By Means Of Belts And Rollers (AREA)
  • Advancing Webs (AREA)
  • Preliminary Treatment Of Fibers (AREA)
  • Registering, Tensioning, Guiding Webs, And Rollers Therefor (AREA)
US29816A 1970-04-20 1970-04-20 Method of and apparatus for imparting an electrical charge to a web of film or paper or the like Expired - Lifetime US3670203A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US2981670A 1970-04-20 1970-04-20

Publications (1)

Publication Number Publication Date
US3670203A true US3670203A (en) 1972-06-13

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Application Number Title Priority Date Filing Date
US29816A Expired - Lifetime US3670203A (en) 1970-04-20 1970-04-20 Method of and apparatus for imparting an electrical charge to a web of film or paper or the like

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US (1) US3670203A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
BE (1) BE765970R (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
DE (1) DE2118910B2 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
FR (1) FR2092055B2 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
GB (1) GB1327148A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
IT (1) IT984553B (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4402035A (en) * 1980-09-02 1983-08-30 Polaroid Corporation Low voltage electrostatic charge regulating apparatus
US5041941A (en) * 1989-12-06 1991-08-20 Westvaco Corporation Charge control for EB coated paperboard
US5121285A (en) * 1991-02-11 1992-06-09 Eastman Kodak Company Method and apparatus for eliminating residual charge on plastic sheets having an image formed thereon by a photocopier
US5205212A (en) * 1989-03-17 1993-04-27 Wolfe Gene H Method of reducing ink electrets in gravure web printing
US5228373A (en) * 1990-01-08 1993-07-20 Robert A. Foisie Method and apparatus using electrostatic charges to temporarily hold packets of paper
US5377069A (en) * 1989-04-07 1994-12-27 Andreasson; Tomas Oscillating circuit for the elimination/reduction of static electricity
US5669047A (en) * 1989-03-03 1997-09-16 Canon Kabushiki Kaisha Charging member, electrophotographic apparatus and charging method using the same
US6368675B1 (en) 2000-04-06 2002-04-09 3M Innovative Properties Company Electrostatically assisted coating method and apparatus with focused electrode field
US6475572B2 (en) 2000-04-06 2002-11-05 3M Innovative Properties Company Electrostatically assisted coating method with focused web-borne charges
US6511581B1 (en) * 1997-09-24 2003-01-28 Valmet Corporation Method for controlling mist and dust in the manufacture and finishing of paper and board by an ion blast wind
US6680086B1 (en) 1998-07-08 2004-01-20 Mesto Paper Oy Method for making paper, assembly for implementing the method and paper product produced by the method
US20100289863A1 (en) * 2009-05-12 2010-11-18 Kabushiki Kaisha Toshiba Neutralization apparatus and printer having neutralization apparatus
US20130105613A1 (en) * 2010-07-07 2013-05-02 Sca Hygiene Products Ab Apparatus for dispensing absorbent sheet products and method for modifying such apparatus

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4233562A (en) * 1978-11-08 1980-11-11 Imperial Chemical Industries Limited Apparatus and method for monitoring web conductivity

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2562138A (en) * 1950-04-04 1951-07-24 Monsanto Chemicals Destaticizing process
US2879396A (en) * 1957-05-03 1959-03-24 Plastics-treating apparatus
US3164747A (en) * 1961-10-18 1965-01-05 Standard Oil Co Static charge control system
US3196063A (en) * 1962-03-28 1965-07-20 Int Paper Co Coated paper and method of producing the same
US3396917A (en) * 1966-03-01 1968-08-13 Du Pont Method for unwinding rolls
US3405052A (en) * 1964-08-26 1968-10-08 Grace W R & Co Apparatus for corona treatment of film including a porous sintered metal electrode
US3503526A (en) * 1967-07-27 1970-03-31 Du Pont Web handling apparatus and process
US3536528A (en) * 1967-08-16 1970-10-27 Agfa Gevaert Nv Electrostatic cleaner and method

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2562138A (en) * 1950-04-04 1951-07-24 Monsanto Chemicals Destaticizing process
US2879396A (en) * 1957-05-03 1959-03-24 Plastics-treating apparatus
US3164747A (en) * 1961-10-18 1965-01-05 Standard Oil Co Static charge control system
US3196063A (en) * 1962-03-28 1965-07-20 Int Paper Co Coated paper and method of producing the same
US3405052A (en) * 1964-08-26 1968-10-08 Grace W R & Co Apparatus for corona treatment of film including a porous sintered metal electrode
US3396917A (en) * 1966-03-01 1968-08-13 Du Pont Method for unwinding rolls
US3503526A (en) * 1967-07-27 1970-03-31 Du Pont Web handling apparatus and process
US3536528A (en) * 1967-08-16 1970-10-27 Agfa Gevaert Nv Electrostatic cleaner and method

Cited By (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4402035A (en) * 1980-09-02 1983-08-30 Polaroid Corporation Low voltage electrostatic charge regulating apparatus
US5669047A (en) * 1989-03-03 1997-09-16 Canon Kabushiki Kaisha Charging member, electrophotographic apparatus and charging method using the same
US5205212A (en) * 1989-03-17 1993-04-27 Wolfe Gene H Method of reducing ink electrets in gravure web printing
US5377069A (en) * 1989-04-07 1994-12-27 Andreasson; Tomas Oscillating circuit for the elimination/reduction of static electricity
US5041941A (en) * 1989-12-06 1991-08-20 Westvaco Corporation Charge control for EB coated paperboard
US5228373A (en) * 1990-01-08 1993-07-20 Robert A. Foisie Method and apparatus using electrostatic charges to temporarily hold packets of paper
US5121285A (en) * 1991-02-11 1992-06-09 Eastman Kodak Company Method and apparatus for eliminating residual charge on plastic sheets having an image formed thereon by a photocopier
US6511581B1 (en) * 1997-09-24 2003-01-28 Valmet Corporation Method for controlling mist and dust in the manufacture and finishing of paper and board by an ion blast wind
US7198841B2 (en) 1998-07-08 2007-04-03 Metso Paper Oy Paper having a cellulosic fiber layer treated with elementary particles
US20040083950A1 (en) * 1998-07-08 2004-05-06 Valmet Corporation Apparatus for making a web of paper or board containing calcium carbonate
US6787196B2 (en) 1998-07-08 2004-09-07 Metso Paper Oy Apparatus for making a web of paper or board containing calcium carbonate
US6680086B1 (en) 1998-07-08 2004-01-20 Mesto Paper Oy Method for making paper, assembly for implementing the method and paper product produced by the method
US20040096649A1 (en) * 1998-07-08 2004-05-20 Metso Paper Oy Paper, board or non-woven product having a cellulosic fiber layer treated with elementary particles
US20040074620A1 (en) * 1998-07-08 2004-04-22 Valmet Corporation Method for treating a paper or board web with a treatment material
US20040079503A1 (en) * 1998-07-08 2004-04-29 Valmet Corporation Use of recycled calcium carbonate in the treatment of a paper, board or nonwoven product
US6716286B2 (en) 2000-04-06 2004-04-06 3M Innovative Properties Company Electrostatically assisted coating method and apparatus with focused electrode field
US6475572B2 (en) 2000-04-06 2002-11-05 3M Innovative Properties Company Electrostatically assisted coating method with focused web-borne charges
US6666918B2 (en) 2000-04-06 2003-12-23 3M Innovative Properties Company Electrostatically assisted coating apparatus with focused web charge field
US6368675B1 (en) 2000-04-06 2002-04-09 3M Innovative Properties Company Electrostatically assisted coating method and apparatus with focused electrode field
US20100289863A1 (en) * 2009-05-12 2010-11-18 Kabushiki Kaisha Toshiba Neutralization apparatus and printer having neutralization apparatus
US8189024B2 (en) * 2009-05-12 2012-05-29 Kabushiki Kaisha Toshiba Neutralization apparatus and printer having neutralization apparatus
US20130105613A1 (en) * 2010-07-07 2013-05-02 Sca Hygiene Products Ab Apparatus for dispensing absorbent sheet products and method for modifying such apparatus
US9908728B2 (en) * 2010-07-07 2018-03-06 Sca Hygiene Products Ab Apparatus for dispensing absorbent sheet products and method for modifying such apparatus
US10118783B2 (en) * 2010-07-07 2018-11-06 Sca Hygiene Products Ab Apparatus for dispensing absorbent sheet products and method for modifying such apparatus

Also Published As

Publication number Publication date
FR2092055A2 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1972-01-21
GB1327148A (en) 1973-08-15
DE2118910A1 (de) 1971-11-11
DE2118910B2 (de) 1975-09-18
FR2092055B2 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1974-10-18
IT984553B (it) 1974-11-20
BE765970R (fr) 1971-09-16

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