US3192043A - Method for developing and fixing electrostatic images in initially partially cured base elements - Google Patents

Method for developing and fixing electrostatic images in initially partially cured base elements Download PDF

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Publication number
US3192043A
US3192043A US142621A US14262161A US3192043A US 3192043 A US3192043 A US 3192043A US 142621 A US142621 A US 142621A US 14262161 A US14262161 A US 14262161A US 3192043 A US3192043 A US 3192043A
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United States
Prior art keywords
liquid
developer
pigment
bonding material
developing
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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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US142621A
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English (en)
Inventor
Metcalfe Kenneth Archibald
Wright Robert John
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Commonwealth of Australia
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Commonwealth of Australia
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Publication date
Priority claimed from AU65385/60A external-priority patent/AU254001B2/en
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Publication of US3192043A publication Critical patent/US3192043A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G13/00—Electrographic processes using a charge pattern
    • G03G13/06—Developing
    • G03G13/10—Developing using a liquid developer, e.g. liquid suspension
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G5/00—Recording members for original recording by exposure, e.g. to light, to heat, to electrons; Manufacture thereof; Selection of materials therefor
    • G03G5/02—Charge-receiving layers
    • G03G5/04—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor
    • G03G5/05—Organic bonding materials; Methods for coating a substrate with a photoconductive layer; Inert supplements for use in photoconductive layers
    • G03G5/0503—Inert supplements
    • G03G5/051—Organic non-macromolecular compounds
    • G03G5/0517—Organic non-macromolecular compounds comprising one or more cyclic groups consisting of carbon-atoms only
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/12—Developers with toner particles in liquid developer mixtures
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/12—Developers with toner particles in liquid developer mixtures
    • G03G9/125—Developers with toner particles in liquid developer mixtures characterised by the liquid

Definitions

  • This invention relates to an improved base element and developer for electrostatic printing and more particularly to methods and means of electrostatic image formation and fixing of selected areas of a surface.
  • An electrostatic printing process is that type of process for producing a' visible record, reproduction or copy by i converting a light image or electric signal into an electrostatic charge pattern on an electrically-insulating base.
  • the process includes the conversion of the electrostatic charge pattern into a visible image by development with suitable charged particles.
  • a typical electrostatic printing process uses an insulating base coated with a suitable photoconductor which on charging produces an overall blanket electrostatic charge on the surface. Such electrostatic charge may be stored in the dark but slowly dissipates with time. During the period inwhich a substantial charge remains, a latent electrostaticimage can be formed by exposing the charged surface to electromagnetic waves which discharge the non-image areas according to the original image leaving the remainder of the surface in a charged condition. The electrostatic image is made visible by applying charged particles in a suitable liquid developer. The visible image as formed is at present fixed to the surface by a fixing agent incorporated in the developing liquid.
  • the fixing of the electrostatic latent-image is accomplished by using a coating of a suitable substance on the base material which is not fully cured and softens by immersing the said base in the developer liquid.
  • the developer particles are thus secured to the surface by incorporating the said particles into the softened coating.
  • One type of base element usable in the foregoing electrostatic printing process comprises a cellulose type sheet coated with a finely divided or particulate photoconductor. dispersed in an electrically-insulated solid film forming vehicle, for example ordinary paper coated with particulate photoconducting white-zinc oxide dispersed in a-resin. It was thought that such recording elements produce satisfactory prints only if the resin binder was cured by time or accelerated by temperature" and that poor prints result if the element wasnot fully cured, but it has now been-found that partial curing (preferably in excess of about percentof ,complete curing) will operate and this then allows softening of the resin by immersion in" the developer liquid and so affords coupling of the developer particle with the resin coating.
  • partial curing preferably in excess of about percentof ,complete curing
  • a necessary feature of this invention is therefore an incomplete curing of the resin coating is made and this allows a softening of the resin face on immersion in the developer liquid. This condition leads to a coupling of the dispersed developer particle suspended in the said liquid to form a combination which does not make it necessary to have a fixing agent in the developer liquid with the suspended developer particles.
  • Curing should be sufficiently complete to ensure that surface softening only of the bonding material takes place without removal of appreciable amounts of the bonding material and consequent release of therphotoconductor medium.
  • FIG. 1 is a schematic cross section of a base element.
  • FIG. 2 is a similar cross section but showing how liquid development is applied to such base element
  • Liquid developer therefore provided the direct means of fixing the image immediately after the carrier liquid was evaporated, the carrier for this purpose having a solvent effect on the fixing substance to ensure that while the developer was in its liquid state, the fixing agent was maintained in a condition where it could effect the necessary bonding.
  • FIG. 3 is a view showing the base element with the image thereon.
  • the base element comprises a sheet of paper 1 or similar medium on the surface of which is formed a conductive layer 2 and on which in turn is a film 3 comprising a bonding medium 4 and a photoconductor 5, the photoconductor being dispersed in the bonding medium 4.
  • the liquid developer 6 comprises a carrier liquid 7 hav- 7 ing an electrical volume resistivity of not less than about 10 ohm centimetre and a dielectric constant of at least 3 so that the liquid will not destroy the electrostatic image on the photoconductor during development, and in this carrier liquid are dispersed the pigment particles 8 which are s'oselected that they will deposit preferentially according to the charge on the photoconductor surface.
  • the carrier liquid 7 is such that it is capable of dissolving the, film 3 at the interface 9, provided the bonding medium 4 has not been fully cured, and according to this invention, therefore the film 3 is cured only sufiiciently to stabilise it to ensure that the image from the photoconductor medium will not be bled away prior to development, this being generally achieved by carrying the curing to at least half way, or somewhat less than what would normally be the fully cured condition of the bonding medium.
  • the base element comprises a backing of paper or the like on which is a'conductive layer 2 such as a layer of aluminum which is vacuum coated or sputtered on to the backing 1 and on this is the film 3 consisting of a bonding medium 4-and a I) photoconductor in which the bonding medium is at least one half cured, the developer used therewith consisting of pigment particles 8 suspended in a carrier liquid 7, which liquid 7 is a solvent for the partially cured bonding medium 4 of the base element.
  • a'conductive layer 2 such as a layer of aluminum which is vacuum coated or sputtered on to the backing 1 and on this is the film 3 consisting of a bonding medium 4-and a I) photoconductor in which the bonding medium is at least one half cured, the developer used therewith consisting of pigment particles 8 suspended in a carrier liquid 7, which liquid 7 is a solvent for the partially cured bonding medium 4 of the base element.
  • a base material is formulated and treated and combined with a developer designed to effect softening of the surface of the material during the course of development are as follows:
  • Example 1 In one example of our invention coating material was prepared according to the following formulation:
  • the next step was to give the coating an electrostatic charge over the surface by subjecting it to the corona discharge from points or wires maintained at high potential relative to the web on which the coating had been made, this operation being carried out in relative darkness.
  • the overall surface charge was dissipated imagewise by exposing the coating to light or X-ray image from a suitable source either by contact or shadow printing or by projection printing or by exposure in a conventional camera.
  • Pigment for example, Microlith Black CT, an organic pigment produced by Ciba Coy. Switzerland gram 1 Carrier liquid, Shellite cc 500 Shellite is the trademark for a hydrocarbon solvent. These constituents were ground together in a pestle and mortar to disperse the pigment in the carrier liquid. The resultant dispersion was used as a developer, the pigment being attracted to the charged areas of the image.
  • the coating material cited in the first part of this example softened slightly in the carrier liquid and upon evaporation of this liquid the pigment was secured to the surface of the coating.
  • Example 2 In another example of our invention, the coating material of the first part was prepared according to the following formulation:
  • Silicone resin Dow Corning No. 804 grams 480 Zinc oxide, Durham Special --do 1200 Toluene millilitres 500 These constituents were ground together in a ball mill or in a single roll mill to secure dispersion of the resin and oxide in the form of a paint. For example, the constituents were milled for 8 hours in a ball mill or for 1 hour in a single roll mill. The resultant paint was diluted with a further 500 millilitres of toluene to produce a satisfactory coating consistency, for example for knife coat- 4. ing, spray coating or dip coating. Curing was effected b heating to 200 F. per hour.
  • Example 2 The coating was then charged and exposed as described in Example 1, following which the latent electrostatic image was developed with a developer of the following composition:
  • Pigment for example, carbon black, Peerless black gram 1 Carrier liquid, cyclohexane millilitres 500 These constituents were ground together to form a dispersion which was then used as a developer.
  • the coat- 7 ing cited in the first part of this example softened slightly The resultant paint was applied to a web of in the cyclohexane carrier liquid and upon evaporation of this liquid the pigment was secured to the surface of the coating.
  • Example 3 In a third example of our invention the coating material used had the following composition:
  • Freon 11 is the trademark of Du Pont de Nemours Corp. for a trichloromonofluoromethane (CCl F).
  • the coating given in the first part of this example softened sumciently in the carrier liquid so that after evaporation the pigment was fixed to the coating.
  • Example 4 In a further example of this invention a coating material was made which ordinarily if fully cured would not soften in any of the liquids commonly used for liquid development. This formulation was as follows:
  • Example 2 With reference to Example 2, the control of softening obtainable in this invention is shown by the fact that at 200 F. fixing was obtained but at 400 F. for one hour none of the common carrier liquids would soften the coating. i i
  • An improved method of developing and simultaneously fixing electrostatic images involving the use of a volatile liquid comprising producing an electrostatic image on a photoconductor embedded in 1a fusible polymeric bonding material on a base, said bonding material being partially cured to the degree that it is soluble to a limited extent in said liquid, then developing said electrostatic image by applying to the surface of the bonding material a developer which comprises a pigment suspended in said volatile liquid, said liquid being of an electrical resistivity sufiiciently high to prevent destruction of the electrostatic image during development, the bonding material being softened due to its solubility in said liquid to enable the pigment to penetrate the bonding material upon deposition thereon, at least some of the pigment being totally embedded in said bonding material, and then evaporating the carrier liquid of the developer to harden the bonding medium to hold the pigment.
  • An improved method of developing and simultaneously fixing electrostatic images involving the use of a volatile liquid and a fusible polymeric bonding medium which in less than fully cured condition is soluble in said liquid, said method comprising embedding a photoconductor medium in said bonding medium which is positioned on a base, partially curing the said bonding medium to at least half of its fully cured condition whereby it remains soluble in said liquid, producing an electrostatic image on the photoconductor medium embedded in said partly cured bonding material by charging and exposing to a light image, then applying said volatile liquid to the said bonding medium, said liquid having an electrical resistivity sufiiciently high to prevent destruction of the electrostatic image during development and hav ing dispersed therein a pigment attractable to said image, the bonding medium being softened by the liquid to enable deposition pigment to penetrate the bonding medium under deposition thereon, at least some of the pigment being totally embedded in said bonding material, and then evaporating the liquid to harden the bonding medium to hold the pigment.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Liquid Developers In Electrophotography (AREA)
  • Photoreceptors In Electrophotography (AREA)
US142621A 1960-10-07 1961-10-03 Method for developing and fixing electrostatic images in initially partially cured base elements Expired - Lifetime US3192043A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
AU65385/60A AU254001B2 (en) 1960-10-07 An improved base material for electrostatic printing processes and method of use

Publications (1)

Publication Number Publication Date
US3192043A true US3192043A (en) 1965-06-29

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US142621A Expired - Lifetime US3192043A (en) 1960-10-07 1961-10-03 Method for developing and fixing electrostatic images in initially partially cured base elements

Country Status (6)

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US (1) US3192043A (fr)
BE (1) BE608877A (fr)
CH (1) CH406850A (fr)
DE (1) DE1205829B (fr)
GB (1) GB1000983A (fr)
NL (1) NL269992A (fr)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3322537A (en) * 1963-11-29 1967-05-30 Rca Corp Electrophotographic reproduction process including removal of electroscopic particles from developed electrostatic image
US3385699A (en) * 1963-07-25 1968-05-28 Fuji Photo Film Co Ltd Process for processing electrophotosensitive layers
US3490368A (en) * 1964-12-30 1970-01-20 Xerox Corp Printing by particulate images
US3535244A (en) * 1966-04-27 1970-10-20 Dick Co Ab Liquid developer composition for electrostatic images
US3717461A (en) * 1970-02-12 1973-02-20 Fuji Photo Film Co Ltd Removal of protective resin layer by liquid developer in electrophotographic imaging
US3791823A (en) * 1965-05-28 1974-02-12 Xerox Corp Photoelectrophoretic imaging transfer method
US3907695A (en) * 1969-07-01 1975-09-23 Alan B Amidon Liquid developer

Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2579332A (en) * 1950-02-11 1951-12-18 Gen Electric Method for increasing the viscosity of liquid resinous organopolysiloxanes
US2735784A (en) * 1953-07-30 1956-02-21 Process of electrostatic printing
US2857271A (en) * 1954-09-28 1958-10-21 Rca Corp Electrostatic printing process for producing photographic transparencies
US2862815A (en) * 1953-10-01 1958-12-02 Rca Corp Electrophotographic member
US2907674A (en) * 1955-12-29 1959-10-06 Commw Of Australia Process for developing electrostatic image with liquid developer
US2946682A (en) * 1958-12-12 1960-07-26 Rca Corp Electrostatic printing
US2954291A (en) * 1957-01-04 1960-09-27 Haloid Xerox Inc Method for preparing a spirit duplicating master
US2959481A (en) * 1958-12-18 1960-11-08 Bruning Charles Co Inc Electrophotographic recording member and process of producing same
US2993787A (en) * 1955-08-30 1961-07-25 Rca Corp Electrostatic printing
US3010842A (en) * 1955-08-29 1961-11-28 Xerox Corp Development of electrostatic images
US3041168A (en) * 1959-09-18 1962-06-26 Rca Corp Electrostatic printing
US3043684A (en) * 1955-01-26 1962-07-10 Gen Dynamics Corp Electrostatic printing

Patent Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2579332A (en) * 1950-02-11 1951-12-18 Gen Electric Method for increasing the viscosity of liquid resinous organopolysiloxanes
US2735784A (en) * 1953-07-30 1956-02-21 Process of electrostatic printing
US2862815A (en) * 1953-10-01 1958-12-02 Rca Corp Electrophotographic member
US2857271A (en) * 1954-09-28 1958-10-21 Rca Corp Electrostatic printing process for producing photographic transparencies
US3043684A (en) * 1955-01-26 1962-07-10 Gen Dynamics Corp Electrostatic printing
US3010842A (en) * 1955-08-29 1961-11-28 Xerox Corp Development of electrostatic images
US2993787A (en) * 1955-08-30 1961-07-25 Rca Corp Electrostatic printing
US2907674A (en) * 1955-12-29 1959-10-06 Commw Of Australia Process for developing electrostatic image with liquid developer
US2954291A (en) * 1957-01-04 1960-09-27 Haloid Xerox Inc Method for preparing a spirit duplicating master
US2946682A (en) * 1958-12-12 1960-07-26 Rca Corp Electrostatic printing
US2959481A (en) * 1958-12-18 1960-11-08 Bruning Charles Co Inc Electrophotographic recording member and process of producing same
US3041168A (en) * 1959-09-18 1962-06-26 Rca Corp Electrostatic printing

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3385699A (en) * 1963-07-25 1968-05-28 Fuji Photo Film Co Ltd Process for processing electrophotosensitive layers
US3322537A (en) * 1963-11-29 1967-05-30 Rca Corp Electrophotographic reproduction process including removal of electroscopic particles from developed electrostatic image
US3490368A (en) * 1964-12-30 1970-01-20 Xerox Corp Printing by particulate images
US3791823A (en) * 1965-05-28 1974-02-12 Xerox Corp Photoelectrophoretic imaging transfer method
US3535244A (en) * 1966-04-27 1970-10-20 Dick Co Ab Liquid developer composition for electrostatic images
US3907695A (en) * 1969-07-01 1975-09-23 Alan B Amidon Liquid developer
US3717461A (en) * 1970-02-12 1973-02-20 Fuji Photo Film Co Ltd Removal of protective resin layer by liquid developer in electrophotographic imaging

Also Published As

Publication number Publication date
NL269992A (fr)
BE608877A (fr)
DE1205829B (de) 1965-11-25
CH406850A (fr) 1966-01-31
GB1000983A (en) 1965-08-11

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