US3739246A - Process and apparatus for increasing the charge density of insulators - Google Patents

Process and apparatus for increasing the charge density of insulators Download PDF

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Publication number
US3739246A
US3739246A US00097946A US3739246DA US3739246A US 3739246 A US3739246 A US 3739246A US 00097946 A US00097946 A US 00097946A US 3739246D A US3739246D A US 3739246DA US 3739246 A US3739246 A US 3739246A
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United States
Prior art keywords
electrode
electrons
conductive layer
gas ions
electrically conductive
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Expired - Lifetime
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US00097946A
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English (en)
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G Haas
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Kalle GmbH and Co KG
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Kalle GmbH and Co KG
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    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
    • B29C48/07—Flat, e.g. panels
    • B29C48/08—Flat, e.g. panels flexible, e.g. films
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25—Component parts, details or accessories; Auxiliary operations
    • B29C48/88—Thermal treatment of the stream of extruded material, e.g. cooling
    • B29C48/911—Cooling
    • B29C48/9135—Cooling of flat articles, e.g. using specially adapted supporting means
    • B29C48/915—Cooling of flat articles, e.g. using specially adapted supporting means with means for improving the adhesion to the supporting means
    • B29C48/9165—Electrostatic pinning
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C55/00—Shaping by stretching, e.g. drawing through a die; Apparatus therefor
    • B29C55/02—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D7/00—Producing flat articles, e.g. films or sheets
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C71/00—After-treatment of articles without altering their shape; Apparatus therefor

Definitions

  • ABSTRACT This invention relates to a process and apparatus for increasing the charge density on the surface of a dielectric material in which electrons and gas ions are produced in the gas space above the surface of the material by means of direct current so that the surface is electrostatically charged.
  • the process is an improvement which comprises producing an electric field of the same polarity above the source which generates the electrons and gas ions, whereby the migration of the electrons and gas ions to the surface of the material is directed.
  • PROCESS AND APPARATUS FOR INCREASING THE CHARGE DENSITY F INSULATORS This invention relates to a process for increasing the charge density during electrostatic charging of the surface of electrically nonconductive materials, in particular of plastic materials, and to an apparatus for performing this process.
  • the present invention provides means of increasing the charge density during electrostatic charging of electrically nonconductive materials, while avoiding the above mentioned disadvantages.
  • direct current is used to produce electrons and gas ions in the space above the material in order to electrostatically charge the surface thereof.
  • an electric field of the same polarity is produced above the source which generates the electrons and gas ions.
  • the expression direct current includes also those voltages which include a certain proportion of residual ripple. Due to the fact that the space surrounding the electrode is of the same polarity as the electrons and gas ions generated, they are prevented from migrating into this space and are almost completely directed toward the surface of the material.
  • the process of the invention has the advantage that considerably less electrons and gas ions must be produced to achieve a charge density on the surface of the material which is comparable to that obtainable by earlier processes, which means that a considerably higher charge can be given to the surface by applying the same voltage to the electrode.
  • the source which generates the electrons and gas ions is additionally heated.
  • the process can be performed using voltages between 200 V and 5 kV, preferably between 500 V and 1,000 V, which eliminates serious problems in the insulation of the electrode without reducing the number of electrons and gas ions produced.
  • the process of the invention is operated at a direct current of 2 to 30 kV, preferably between 10 and 15 kV. Depending upon the polarity of the electrode producing the electrons and gas ions, an electric field of the same polarity is produced above this source.
  • the source producing this electric field will be designated as a directional electrode.
  • the maximum charge density which can be produced on the surface of the material without damage to the film can be calculated according to the following formula D e, e E[A sec./V cm V/cm] A sec/cm wherein s the dielectric constant of the vacuum,
  • E the dielectric strength of the material, which depends not only upon the kind of material, but also upon its thickness.
  • the invention relates further to an apparatus for performing the process. It comprises a grounded support on which the nonconductive material rests, and an electrode arranged above the material, which is pro vided with direct current by a voltage generator.
  • the polarity may be either positive or negative.
  • the directional electrode is arranged which consists of an electrically conductive layer connected to a voltage generator of the same polarity and insulated from the other parts of the apparatus.
  • the electrically conductive layer consists of one or more wires and/or metal strips connected to the voltage generator. Layers, for example metal layers, which are applied to a nonconductive support by vacuumdeposition and/or lamination, also may be used.
  • the directional electrode corresponds in its shape to the electrode generating the electrons and gas ions, which may be of a predetermined shape.
  • a measuring instrument is interposed between the electrically conductive layer and the voltage generator, in order to be able to measure the flow of current and to adjust the directional electrode. In this manner, it can be easily determined whether and to which degree electrons and gas ions flow from the electrode to the directional electrode during electrostatic charging.
  • a highly ohmic resistance is interposed between the directional electrode and thereference potential, instead of connecting the directional electrode to a high-voltage gensuch that only as many electrons and gas ions flow away as reach the directional electrode.
  • the resistance to be interposed is in the range of from 20 to Meg Ohm (M0).
  • a measuring instrument is interposed between the resistance and the reference potential to measure the flow of current.
  • a variableresistance is provided in order to enable a fast readjustment, for example when the electrode voltage changes.
  • the distance between the directional electrode and the electrode, and the distance between the electrode and the surface of the material can be varied within certain limits, it has proved to be of advantage in practice for the distance between the directional electrode and the electrode to be about equal to the distance between the electrode and the material surface.
  • the distances range from 0.1 to 15 cm., preferably from 1 to 5 cm.
  • EXAMPLE 1 A thin steel wire of 0.3 mm diameter was clamped between electrically insulated mountings over a grounded roller and at a distance of cm therefrom. When the voltages stated below were applied to the wire, the following current values were measured:
  • EXAMPLE 2 The same arrangement was used as in Example 1, except that, above the taut wire and at a distance of mm therefrom, a curved elongated directional electrode of about 2 cm width was clamped in insulated mountings. This directional electrode was electrically connected with a voltmeter and had a resistance to ground of the order of a few 1,000 Meg Ohm. When different voltages were applied to the wire, the following values were measured, U 1 being the voltage at the wire, U 2 the voltage at the directional electrode, and J l the current issuing from the wire. At equal voltages, the current is markedly lower than in Example 1:
  • EXAMPLE 3 The arrangement used was the same as in Example 2, except that voltages of varying magnitudes were additionally applied to the directional electrode.
  • the current values obtained range between those of Example 1 and Example 2, depending on the voltage applied to the directional electrode. The following values were measured:
  • FIG. 1 shows a section 1 of a web of nonconductive material conveyed on a grounded roller 2.
  • An insulated curved directional electrode 3 is arranged above the web. Via an instrument 4 for measuring the current flow, the directional electrode 3 is connected to a voltage generator 5 fed from the electric supply line N. Between the web 1 and the directional electrode 3, there is the insulated electrode 6 which generates the electrons and gas ions and which, in this case, is fed from the electric supply line N via a voltage generator 7. In this device, the electrode is also heated by the heating device 9 via the connecting wires 8.
  • the apparatus is capable of many variations.
  • the high voltage generator 5 is replaced by an appropriate resistance, which may be variable.
  • FIGS. 2, 3 and 4 show the highly ohmic resistance 5a which is employed instead of a voltage generator 5 in FIG. 1.
  • FIG. 3 shows a conductive layer applied to a dielectric support 3a
  • FIG. 4 shows the wire 3a which replaces the directional electrode 3 of FIG. 1.
  • An apparatus for increasing the charge density on a surface of a dielectric material which comprises grounded support means, electrode means mounted above the support means and connected to a D.C. source, and an electrically conductive layer means above the electrode means and being connected to a reference potential over a highly ohmic resistance and insulated from the remainder of the apparatus.
  • An apparatus according to claim 1 including means for heating the electrode means.
  • An apparatus including current measuring means between the highly ohmic resistance and the electrically conductive layer.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Chemical Vapour Deposition (AREA)
  • Treatments Of Macromolecular Shaped Articles (AREA)
  • Electrostatic Charge, Transfer And Separation In Electrography (AREA)
  • Elimination Of Static Electricity (AREA)
US00097946A 1969-12-17 1970-12-14 Process and apparatus for increasing the charge density of insulators Expired - Lifetime US3739246A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19691963248 DE1963248B2 (de) 1969-12-17 1969-12-17 Verfahren und vorrichtung zur erhoehung der ladungsdichte auf der oberflaeche eines elektrisch nicht leitenden materials

Publications (1)

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US3739246A true US3739246A (en) 1973-06-12

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US00097946A Expired - Lifetime US3739246A (en) 1969-12-17 1970-12-14 Process and apparatus for increasing the charge density of insulators

Country Status (11)

Country Link
US (1) US3739246A (enrdf_load_stackoverflow)
AT (1) AT315473B (enrdf_load_stackoverflow)
BE (1) BE760381A (enrdf_load_stackoverflow)
CA (1) CA921973A (enrdf_load_stackoverflow)
CH (1) CH519979A (enrdf_load_stackoverflow)
DE (1) DE1963248B2 (enrdf_load_stackoverflow)
FR (1) FR2073907A5 (enrdf_load_stackoverflow)
GB (1) GB1325580A (enrdf_load_stackoverflow)
NL (1) NL7017829A (enrdf_load_stackoverflow)
SE (1) SE365976B (enrdf_load_stackoverflow)
SU (1) SU471745A3 (enrdf_load_stackoverflow)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3851229A (en) * 1973-06-21 1974-11-26 Xerox Corp Current measuring device
US4047238A (en) * 1975-06-13 1977-09-06 Hoechst Aktiengesellschaft Apparatus and process for electrostatically charging a recording material
US4068585A (en) * 1973-05-11 1978-01-17 Electroprint, Inc. Electrostatic printer support with controlled electrostatic surface voltage
US4227233A (en) * 1976-10-01 1980-10-07 Olympus Optical Company Limited Corona discharge device for electrographic apparatus
US4326454A (en) * 1978-04-03 1982-04-27 Consan Pacific Incorporated Ion treatment enhancement
US4637709A (en) * 1983-12-23 1987-01-20 Fuji Xerox Co., Ltd. Apparatus for generating an image from within a sheet-like member
US5295039A (en) * 1989-03-10 1994-03-15 Fuji Photo Film Co., Ltd. Method of applying single polar electro-static charges to continuously travelling long web support, and apparatus practicing same
EP0707940A3 (en) * 1994-10-18 1996-11-06 Eastman Kodak Co Device for electrostatic plating
CN110036695A (zh) * 2016-12-13 2019-07-19 三菱电机株式会社 除电装置以及除电方法

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3820929A (en) * 1972-12-14 1974-06-28 Celanese Corp Electrostatic pinning of polymeric film
FR2415528A1 (fr) * 1978-01-25 1979-08-24 Cellophane Sa Amelioration aux procedes de fabrication de films par placage electrostatique
DE3065217D1 (en) * 1980-01-31 1983-11-10 Kleinewefers Ramisch Gmbh Apparatus for expanding and/or maintaining the expansion of a moving web
JP3944889B2 (ja) * 1997-05-13 2007-07-18 富士フイルム株式会社 ウエブ帯電用装置
EP3076766A1 (en) * 2015-03-31 2016-10-05 F. Hoffmann-La Roche AG Method and apparatus for electrostatically discharging a primary packaging container made of plastics

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2588699A (en) * 1943-08-27 1952-03-11 Chester F Carlson Electrophotographic apparatus
US2868989A (en) * 1956-01-03 1959-01-13 Haloid Xerox Inc Electrostatic charging method and device
US3196270A (en) * 1962-07-31 1965-07-20 Union Carbide Corp Treating of plastic surfaces
US3541329A (en) * 1966-12-01 1970-11-17 Xerox Corp Negative corona device with means for producing a repelling electrostatic field
US3554161A (en) * 1968-11-14 1971-01-12 Addressograph Multigraph Developing apparatus
US3557367A (en) * 1967-09-01 1971-01-19 Xerox Corp Method and apparatus for increasing the efficiency of corona charging of a photoconductor

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2588699A (en) * 1943-08-27 1952-03-11 Chester F Carlson Electrophotographic apparatus
US2868989A (en) * 1956-01-03 1959-01-13 Haloid Xerox Inc Electrostatic charging method and device
US3196270A (en) * 1962-07-31 1965-07-20 Union Carbide Corp Treating of plastic surfaces
US3541329A (en) * 1966-12-01 1970-11-17 Xerox Corp Negative corona device with means for producing a repelling electrostatic field
US3557367A (en) * 1967-09-01 1971-01-19 Xerox Corp Method and apparatus for increasing the efficiency of corona charging of a photoconductor
US3554161A (en) * 1968-11-14 1971-01-12 Addressograph Multigraph Developing apparatus

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4068585A (en) * 1973-05-11 1978-01-17 Electroprint, Inc. Electrostatic printer support with controlled electrostatic surface voltage
US3851229A (en) * 1973-06-21 1974-11-26 Xerox Corp Current measuring device
US4047238A (en) * 1975-06-13 1977-09-06 Hoechst Aktiengesellschaft Apparatus and process for electrostatically charging a recording material
US4227233A (en) * 1976-10-01 1980-10-07 Olympus Optical Company Limited Corona discharge device for electrographic apparatus
US4326454A (en) * 1978-04-03 1982-04-27 Consan Pacific Incorporated Ion treatment enhancement
US4637709A (en) * 1983-12-23 1987-01-20 Fuji Xerox Co., Ltd. Apparatus for generating an image from within a sheet-like member
US5295039A (en) * 1989-03-10 1994-03-15 Fuji Photo Film Co., Ltd. Method of applying single polar electro-static charges to continuously travelling long web support, and apparatus practicing same
EP0707940A3 (en) * 1994-10-18 1996-11-06 Eastman Kodak Co Device for electrostatic plating
CN110036695A (zh) * 2016-12-13 2019-07-19 三菱电机株式会社 除电装置以及除电方法

Also Published As

Publication number Publication date
FR2073907A5 (enrdf_load_stackoverflow) 1971-10-01
CH519979A (de) 1972-03-15
DE1963248B2 (de) 1972-02-17
DE1963248A1 (de) 1971-07-29
NL7017829A (enrdf_load_stackoverflow) 1971-06-21
SE365976B (enrdf_load_stackoverflow) 1974-04-08
GB1325580A (en) 1973-08-01
SU471745A3 (ru) 1975-05-25
BE760381A (fr) 1971-06-15
CA921973A (en) 1973-02-27
AT315473B (de) 1974-05-27

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