US3923504A - Migration imaging member and method - Google Patents

Migration imaging member and method Download PDF

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US3923504A
US3923504A US327363A US32736373A US3923504A US 3923504 A US3923504 A US 3923504A US 327363 A US327363 A US 327363A US 32736373 A US32736373 A US 32736373A US 3923504 A US3923504 A US 3923504A
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migration
softenable
layer
conductive
dielectric layer
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Lloyd F Bean
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Xerox Corp
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Xerox Corp
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G17/00—Electrographic processes using patterns other than charge patterns, e.g. an electric conductivity pattern; Processes involving a migration, e.g. photoelectrophoresis, photoelectrosolography; Processes involving a selective transfer, e.g. electrophoto-adhesive processes; Apparatus essentially involving a single such process
    • G03G17/10—Electrographic processes using patterns other than charge patterns, e.g. an electric conductivity pattern; Processes involving a migration, e.g. photoelectrophoresis, photoelectrosolography; Processes involving a selective transfer, e.g. electrophoto-adhesive processes; Apparatus essentially involving a single such process using migration imaging, e.g. photoelectrosolography

Definitions

  • migration imaging systems entail imagewise migration in depth of marking materials through a softenable material.
  • An electrical laent image is created on an imaging member composed of marking particles dispersed in, or layered in, or layered on, a softenable material.
  • Development of this latent image is effected by reducing the resistance of the softenable material to marking particle migration, i.e., it is rendered permeable to the marking particles.
  • Certain marking particles migrate because they associate with the charge of the latent image and the migrated and nonmigrated particles constitute complementary images.
  • the complementary images may be separated by various techniques, the softenable material may be dissolved and washed away freeing the migrated image but at the expense of losing the non-migrated image.
  • the softenable material may be split at a level between migrated and unmigrated particles, thereby freeing both images, as described in copending application U.S. Ser. No. 784,164 filed Dec. 16, 1968 now U.S. Pat. No. 3,741,757.
  • microelectronic circuitry involves many objectional steps such as the tedious requirement of forming a silver transparency of the printed circuit, vacuum evaporation of metals, photopolymerization through contact exposure through the silver transparency, selective removal of the unpolymerized material with hazardous solvents, and chemical etching using corrosive liquids.
  • a typical procedure for making printed circuits involve the provisioning of a ceramic layer overcoated with a conductive material which in turn is overcoated with a photoresist material. The photoresist layer is then contact exposed through the silver transparency to ultraviolet light and polymeriz'es in exposed areas. Next, the silver transparency is removed and the unpolymerized photoresist is stripped away.
  • a corrosive liquid is brought into contact with the now exposed portions of the conductive layer and such exposed portions are etched away by the corrosive liquids.
  • the polymerized photoresist is then removed revealing portions of the conductive layer, previously protected during the etching process by the polymerized resist, which conductive portions are in the configuration of the silver transparency.
  • the silver transparency of the circuit diagram would yield after the etching step conductive portions of the conductive layer, in the configuration of a predetermined surface area with leads emanating therefrom and residing upon a ceramic substrate.
  • a coating of dielectric material is then coated over both the ceramic substrate and the metal. After applying the dielectric coating, the dielectric coating is overcoated with a conductive layer which, in turn is overcoated with a photoresist layer.
  • the previous steps taken to form the simple resistor are again performed; contact exposing through a silver transparency with ultraviolet light to photopolyme'rize the photoresist; removing the unpolymerized photoresist; etching away the exposed portions of the conductive layer; and removing the photopolymerizcd photoresist.
  • Another object of this invention is to provide a camera speed method of preparing circuit components without the need for intermediate silver transparencys.
  • a still further object of this invention is to provide micro sized circuit components through direct optical reduction without the need to consecutively go through intermediate steps of pattern reduction.
  • a migration member comprising layers of materials having the requisite characteristics suitable for microelectronic or other circuitry, especially passive elements thereof such as resistors and capacitors, at least one layer of which contains conductive migration material which may optionally be fusible, selectively migrating the migration material so that at least one of migrated and unmigrated migration materials form a continuous mass of material having the desired characteristic in the desired circuit component or network configuration.
  • the imaging member can be selected from several embodiments.
  • One embodiment imaging member comprises a softenable dielectric layer, an optionally softenable photoconductive layer and a softenable migration layer containing conductive migration. material.
  • a second embodiment imaging member comprises a dielectric support coated on each side with a softenable dielectric layer, each of which dielectric layers is over coated with an optional softenable photoconductive layer, each of which softenable photoconductive layers are overcoated with a softenable migration layer containing conductive migration material.
  • An electrical latent image is formed on the imaging member.
  • portions of the migration material in the migration layer migrate into the dielectric layer with the remainder of migration material remaining in the migration layer atop the dielectric or optional photoconductive layer and in-depth.
  • the migrating migration material is usually able to migrate into the dielectriclayer.
  • the degree of dissimilarity which calls for circulation in accordance with the present invention is any dissimilarity which prevents the migration of migrating material from the migration layer or layers and into the dielectric layer under imaging process conditions in the absence of the dielectric layer circulating.
  • immiscible layers or materials are an example of the degree of dissimilarity which calls for circulating the dielectric layer.
  • immiscible layers or materials are used herein to include two or more layers or materials which can be cast such that a distinct interface or interfaces, including viscosity gradients, exists therebetween even though the layers or materials can be cast to have no distinct interface or interfaces under other conditions; and include materials which initially have a distinct interface but which diffuse into one another either in time or under certain conditions outside those in the imaging process.
  • circulation is used herein to mean the movement of softenable material, generally in a circular convection pattern, at a reduced viscosity and in response to a charge density at or above the threshold level of circulation.
  • threshold level of circulation is used herein to mean the charge density at which the circulation layer begins to circulate.
  • softenable as used herein is intended to mean any substantially electrically insulating material which may be rendered more permeable to particles migrating through its bulk by the development step of the process' disclosed.
  • changing permeability is accomplished by the above mentioned softening techniques of exposure to heat, partial solvent or solvent vapor, or combinations thereof or by washaway techniques as disclosed in copending application Ser. No. 837,591 filed on June 30, 1969, hereby incorporated by reference, and is alternatively referred to as decreasing the resistance to migration of migration material in depth at least sufficient to allow imagewise migration of migration material in depth.
  • electrical latent image and the several variant forms thereof used herein includes the images formed by the charge-expose mode hereof which cannot readily be detected by standard electrometric techniques as an electrostatic image for example of the type found in xerography, so that no readily detectable or at best a very small change in the electrostatic or coulombic force is found after exposure (when using preferred exposure levels); and electrostatic latent images of a type similar to those found in xerography which are typically readily measurable by standard electrometers,
  • various entire layers of softenable material may be removed such as, for example, swabbing with a solvent loaded swab; or, only the softenable material can be removed leaving behind migration material residing in-depth atop the next lower layer by immersion of the imaged member in a suitable solvent such as, for example, various discrete kerosene fractions.
  • FIG. lA-D are a partial schematic illustrative cross section of a first embodiment imaging member during various imaging process steps.
  • FIG. 2 is a partial schematic illustration of a cross section of a second embodiment imaged member according to the invention.
  • FIG. 3. is a partial schematic illustration of a cross section of yet another embodiment according to this invention.
  • the partial schematic illustrations of the imaging members are not to scale; but rather, illustrate the structural and functional relationships between the migration material, softenable layers and substrate layers.
  • a layered imaging member comprising a conductive support 10, a substantially electrically insulating softenable layer 11, a softenable photoconductive layer 12, and a migration layer 13 comprising migration material particles 14 and softenable material 15.
  • Layers 11, 12 and 13 all contain softenable material but each layer is given a different descriptive name as a matter of convenience for an indication of structure or function.
  • the softenable material is generally chemically inert and substantially electrically insulating during the imaging and development phases of the migration imaging process.
  • the photoconductive layer 12 which contains softenable material also contains sufficient photoconductive materials therein so as to render the entire layer photoconductive as a practical matter.
  • the softenable materials are such that they are readily softened by liquid partial solvent, solvent vapors, heat or any combination thereof which may be employed during the development phase of the process.
  • the migration material may be continuous or particulate; but if continuous, should be .fracturable.
  • fracturable is meant that the migration material is capable of being broken up into particles before or during the image forming process.
  • the migration materials preferably are substantially insoluble in the softenable material and otherwise not adversely reactive therewith and also insoluble in any solvent, liquid or vapor, which may be used in the softening step.
  • Substrate 10 in the embodiment depicted in FIG. 1 is preferably electrically conductive but can be dielectrical.
  • Conductive substrates generally facilitate the charging of the imaging member and for purposes of the embodiment depicted in FIG. 1, becomes an elemental component of the circuitry when capacitors are desired.
  • Conductive substrates typically may be of metals, such as brass, copper, chromium, stainless steel, zinc, ormay be conductive plastics and rubbers.
  • the conductive substrate may be coated on an insulator or dielectri'c such as plastic, glass, or paper; for example,
  • the softenable material of softenable layer 11, softenable photoconductive layer 12, and softenable matrix layer 13 may comprise any suitable softenable material.
  • Classes of materials falling within this definition include polystyrenes, alkyd substituted polystyrenes, polyolefins, styreneacrylate copolymers, styrene-olefin copolymers, silicone resins, phenolic resins, and organic amorphous glasses.
  • Typical materials are Staybelite Ester 10, a partially hydrogenated rosin ester, Foral Ester, a hydrogenated rosin triester, and Neolyne 23, an alkyd resin, all from Hercules Powder Co., SR 82, SR 84, silicone resins, both obtained from General Electric Corporation; Sucrose Benzoate, Eastman Chemical; Velsicol X-37, a polystyrene-olefin copolymer from Velsicol Chemical Corp.; Hydrogenated Piccopale 100, a highly branched polyolefin, PIP-100, hydrogenated Piccopale 100, Piccotex 100, a copolymer of methyl styrene and vinyl toluene, Piccolastic A-75, 100 and 125, all polystyrenes, Piccodiene 2215, a polystyrene-olefin copolymer, all from Pennsylvania Industrial Chemical Co., Araldite 6060 and 6071, epoxy resins
  • the softenable photoconductive layer 12 comprise any suitable material dispersed in any of the above listed softenable materials.
  • the photosensitive material may consist of any suitable inorganic or organic photosensitive material.
  • Typical inorganic materials are listed in U.S. Pat. No. 3,121,006 to Middleton et a1 and in US. Pat. No. 3,288,603, both of which are hereby incorporated by reference.
  • Typical inorganic materials include vitreous selenium, vitreous selenium allowed with arsenic, tellurium, antimony or bismuth, etc.; cadmium sulfide, zinc oxide, cadmium sulfoselenide,and many others.
  • Typical organic photosensitive materials include phthalocyanine pigments such as the x-form of metal phthalocyanine described in U.S. Pat. No. 3 ,3 57,989 to Byrne et al,metal phthalocyanines, such as copper phthalocyanines;
  • quinacridones available from DuPont under the trade names Monastral Red, Monastral Violet,and Monastral Red Y; substituted 2,4-diamino-triazines disclosed by Weinberger in U.S. Pat. No. 3,445,227; triphenodioxazines disclosed by Weinberger in U.S. Pat. No. 3,442,781; polynuclear aromatic quinones available from Allied Chemical Corporation under the trade name lndofest Double Scarlet, lndofest Violet Lake B, lndofest Brilliant Scarlet and lndofest Orange.
  • the above list of photosensitive materials shouldin no way be taken as limiting, but is merely illustrative of suitable 6 materials.
  • the size of the photosensitive particles is not critical; particles in size range from about .1 micron to about 1 micron in average diameter work well.
  • softenable photoconductive layer 12 Satisfactory thicknesses for softenable photoconductive layer 12 are from about 0.5 micron to about 5 microns; preferred thicknesses are from about 0.5 micron to about 1 micron. On a weight basis satisfactory ratios of photoconductive particles to softenable material in the photoconductive layer 12 are in the range from about 1:6 to about 4:1; preferred weight ratios are in the range from about 1:3 to 2:3. Alternately, the softenable photoconductive layer 12 can comprise softenable material rendered photoconductive by other known techniques.
  • photoconductive dyes may be added to suitable circulation layer materials to broaden the circulation layer spectral response; such as, for example, the addition of Rodamine B dye, a red watersoluble dye available from DuPont, to either TO 1920 and Vinylite VYNS or VYLF (another copolymer of Vinylchloride and vinyl acetates).
  • Rodamine B dye a red watersoluble dye available from DuPont
  • the softenable migration layer 13 comprising particles l4 and softenable material 15 may comprise any suitable softenable material such as those softenable materials listed above.
  • the particles 14 can comprise any suitable conductive material, or can comprise any suitable fusible conductive material.
  • suitable fusible conductive materials include, for example, low melting metals and metal alloys, conductive rubbers and plastics, and insulating materials loaded with conductive materials such as, for example, pigments, dyes or metal salts.
  • Satisfactory loadings of conductive materials such as pigments, dyes or metal salts into fusible material are from about 10 percent to about percent by weight conductive material; from about 30 percent to about 95 percent being preferred.
  • the conductively loaded fusible materials can be conveniently prepared by dispersing the conductive pigments, dyes or metal salts in heated, dissolved or partially dissolved fusible material, and then crushing, ball milling or otherwise breaking up the dried dispersion into particles of the desired sizev Freeze drying is also satisfactory; for example, 3 parts by weight carbon black particles added to 2 parts by weight polyvinyl carbazole in toluene and freeze dried yield suitable fusible conductive particles which can be satisfactorily migrated in Examples I through XV. Such particles will fuse at about 45C; when employed as migration material herein the particles are usually subjected to a separate'fusing step after imaging.
  • Typical suitable fusible conductive low melting alloys include, for example, the binary, ternary, quaternary and quinary mixtures of bismuth, tin, lead, cadmium, indium and other metals.
  • Typical suitable fusible materials which can be conductively loaded include, for example, P-1700-618 Magenta Fluorescent Pigment, available from Radiant Color Company, Richmond, California; vinylidene fluoride available under the name Kynar from Pennsalt Chemical Co.; polystyrene;
  • the fusible characteristics desired with such fusible materials is the ability of the materials to soften or reduce their viscosities to a point at which adjacently located fusible particles combine into a substantially indistinguishable mass of the fusible material. It is intended that this fusing step take place at conditions which are different from the conditions which cause development of the imaging member by softening, and optionally circulating, the softenable materials in the various layers thereof.
  • Typical suitable fusing conditions may include, for example, the controlled application of a solvent for the fusible particles after the imaging member has been developed; or heating the developed member to a temperature sufficiently high to heat-fuse the fusible particles without adversely affecting the imaged member.
  • the fusible conductive particles are in the topmost layer 13, when exposure is through such layer it is preferred that the particles be at least partially transparent to radiation actinic to photoconduetive layer 12 when layer 12 is employed.
  • Satisfactory thicknesses for softenable migration layer 13 are from about 0.5 micron to about 6 microns; preferred thickness are from about 0.5 micron to about 1 micron.
  • the fusible particle size are typically of a size of from about 0.1 micron to about 2 microns in average diameter.
  • a preferred weight ratio of fusible particles to softenable material in migration layer 13 is from about 1:3 to about 2:3; satisfactory ratios being from about 1:6 to about 4:1. Satisfactory volume ratios are from about 1:19 to about 1:1.
  • the imaging member embodiment of FIG. 1 is preferably electrostatically charged, preferably uniformly electrostatically charged.
  • Such charging is accomplished generally in the substantial absence of radiation actinic to the photoconduetive materials included in softenable photoconductive layer 12.
  • the charging may be accomplished by means of corona discharge devices of the general description and generally operated as disclosed in Vyverberg U.S. Pat. No. 2,836,625 and Walkup U.S. Pat. No. 2,777,957.
  • Other charging techniques ranging from rubbing the member to induction charging for example, as described in Walkup U.S. Pat. No. 2,934,649 are available in the art.
  • the member may be charged using double sided corona charging techniques where two corona charging devices on each side of the member of FIG. 1 and oppositely charged are traversed in register relative to the imaging member.
  • the imaging member After charging, the imaging member is exposed to electromagnetic radiation which is actinic to the photoconductive material included in photoconductive layer 12.
  • electromagnetic radiation which is actinic to the photoconductive material included in photoconductive layer 12.
  • Any suitable actinic electromagnetic radiation may be used. Typical types of radiation include radiation from ordinary incandescent lamps, x-rays, beams of charged particles, infrared, ultraviolet and combinations thereof.
  • the arrows 52 represent actinic electromagnetic radiation for purposes of illustration and in those areas being exposed to such radiation it will be noted further that the electrical field within layer 12 collapses forming two electric fields, one each across layers 11 and 13, and extends across layers ll, 12 and 13 in unexposed areas.
  • any level of charge residing on the surface of layer 13, in dark areas, which is sufficient to cause migration of the particles 14 is satisfactory.
  • the level of charge desirably residing on the surface of layer 13 should be above the circulation threshold level of the softenable material in layer 12 and dielectric layer 11.
  • a generally satisfactory charge density of threshold level of circulation can be found within the range which produces an' electric field strength of from about 10 volts per micron to about 80 volts per micron. A range of from about 30 to about 50 volts per micron being preferred. It is felt that circulation of layer 12 enables penetration where penetration is otherwise impossible, by grouping the migrating particles 14 into groups in the vicinity of the interface of layers 11 and 12 and that the migration of particles 14 are amplified when the particles are so grouped or concentrated; consequently, the particles are believed to thereby be able to penetrate the interface which, in the absence of circulation, would otherwise be inpenetrable.
  • the thickness ranges for softenable photoconduetive layer 12 set out above have been found satisfactory to allow migration of particles 14 through the interface between layers 13 and 12 and the interface between layers 12 and 11 when circulation is required and occurs within layer 11. However, it is to be noted that where greater circulation is required, circulation of both layers 11 and 12 may be resorted to.
  • the softenable materials in layers ll, 12 and 13 including the exposed portions naptholite (Buffalo Solvents and Chemicals).
  • the softening increases the permeability of the softenable materials in layers 11, 12 and 13, and thereby decreases their resistance to migration of particles 14 in depth in the softenable materials.
  • the softening step may involve but a single solvent, solvent vapor, or heat treatment which effectively softens the softenable materials; or, alternatively, the softening step may involve two treatments of heat, solvent, or solvent vapor, or combinations thereof, each treatment of which effectively softens one or more layers.
  • the particles 14 in migration layer 13 remain in layer 13 and migrate to the bottom of layer 13 in the exposed areas in photoconductive embodiments.
  • the particles 14 can be fusible conductive particles such as conductive metals or plastics.
  • the conductive particles are preferably fusible in order to obtain a continuous mass of migration material in nonmigrated areas of the member.
  • the particles 14 form into a continuous mass of conductive material.
  • the softenable material of layer 13 is removed prior to fusing particles 14. It is to be noted of course that the solvent used in the softening step and the solvent used in the removal step are different solvents so that the former softens whereas the latter removes only softenable material 15 leaving particles 14 surprisingly indepth atop thephotoconductive layer 12.
  • FIG. 1D which illustratively depicts immersion of the imaging member in solvent 62 within container 60 illustrates the removal of softenable material 15 from the migration layer 13.
  • the migration layer 13 comprises softenable material 15 throughout layer 13 and comprises migration material 14 in exposed areas of migration layer 13.
  • the softenable material 15 By removing the softenable material 15, only the migration material which did not migrate, i.e., that in exposed areas, remains on the surface of softenable dielectric layer 11 in embodiments where photoconductive layer 12 is omitted.
  • migration material 14 remains indepth, provides complete coverage of exposed areas and does not wash-away in-depth with softenable material 15.
  • the particulated migration material 14 remaining on the surface of dielectric layer 11 can be made resistant to smudging, scratching, smearing or other undesirable defacing by causing some of the softenable material in dielectric layer 11 to flow into the particulated migration material 14 in exposed areas. This may be accomplished, for example, by including material in dielectric layer 11 which is partially soluble in the solvent used to remove softenable material 15; by using a small fraction of solvent in which dielectric layer 11 is soluble in the solvent 62 used to remove softenable material 15, up to about 15 percent by volume being preferred; or by heating dielectric layer 11 to a lower viscosity so that it flows into particulated migration material 14 in exposed areas. This phenomena of flow is believed to be a wicking-type action similar to that of fuel flowing up into a wick.
  • Any suitable method of removing softenable material 15 may be utilized; for example, such as exposing softenable material 15 to solvent. Any suitable solvent which removes softenable material 15 may be used.
  • the solvents above listed with respect to the developing step constitute a listing of typical suitable solvents which can be used in the step of removing softenable material 15. It is to be noted of course that preferably the solvent used in the developing step and the solvent used in the removal step are different solvents so that the former only softens both softenable material 15 and the softenable material in soft-enable dielectric layer 11 whereas the latter solvent removes only softenable material l5 and optionally partially dissolves, softens, or swells the softenable material in layer 11 without removing softenable layer 11.
  • each of the different solvents can be taken from the listing of typical solvents suitable for softening above, or mixtures thereof and with the exercise of care, can provide suitable results.
  • kerosene such as Sohio Odorless Solvent 3440, Sohio Odorless Solvent 3456, and other discrete kerosene fractions.
  • the use of kerosene and similarly mild solvents is preferred because one can conveniently immerse the imaging member in a bath of kerosene, etc. to remove only the softenable material 15 without removing the softenable material of softenable dielectric layer 11 or photoconductive layer 12.
  • softenable material 15 should be chosen accordingly.
  • the softenable material 15 is removed at that time and a removal step may be dispensed with; although a separate fusing step may be desirable, such as, for example, heating the softenable dielectric layer 11 or photoconductive layer 12 to reduce its viscosity sufficient for wicking or bonding of material 14 to layer 11 or layer 12 when layer 12 is employed.
  • the imaging member depicted therein comprises a dielectric support 20 coated on each side with a softenable dielectric layer 21, each of which dielectric layer 21 is overcoated with a softenable photoconductive layer 22, each of which softenable photoconductive layers is overcoated with a softenable migration layer 23, containing migration particles 24 in softenable material 25.
  • the layers 21, 22, and 23 in FIG. 2 correspond to the layers 11, 12, and 13 of FIG. I. All of the above remarks pertaining to the imaging member embodiment in FIG. 1 apply as well as to the: imaging member in embodiment depicted in FIG. 2.
  • the embodiment in FIG. 2 is a double-sided version of the FIG. 1 embodiment.
  • the FIG. 2 is a double-sided version of the FIG. 1 embodiment.
  • the FIG. 1 is a double-sided version of the FIG. 1 embodiment.
  • the FIG. 1 is a double-sided version of the FIG. 1 embodiment.
  • the FIG. 1 is a double-sided version of the FIG. 1 embodiment.
  • the FIG. 1 is a
  • imaging member is preferably charged by the double-sided corona charging technique previously described. Also, photoconductive layers 22 can be omitted in noncharge-expose electrical latent imaging modes.
  • An advantage of the figure 2 embodiment imaging member is that more surface area is available in a single imaging member 4 with which to form various components of the desired circuitry and that the components on both layers 23 may form a single circuit by being provided with a suitable lead between components in each of the layers 23. It is to be noted of course that in each of the embodiments in FIG. 1 and FIG. 2 resistors may easily be formed according to the above described method in layers 13 and 23; and that capacitors are formed by the imaging member structure having, after imaging, two conductive members separated by a dielectric. That is, in FIG.
  • a capacitor is formed in the exposed areas and comprises fused particles 14 as one conductive member and conductive support as a second conductive member and separation being provided by dielectric layer 11.
  • a capacitor made with the FIG. 2 imaging member would comprise fused particles 24 in each of the layers 23 as the two conductive members with separation provided by dielectric support 20 and dielectric layers 21, in exposed areas. It will be appreciated that several choices are available as to which of migrated and non-migrated particles are to be utilized for circuit components. For example, in FIG. 2 a capacitor could comprise the fused particles in layers 21 separated by dielectric support 20.
  • the FIG. 2 imaging member can be satisfactorily employed for migration imaging, generally.
  • the softenable dielectric layer need be only a layer of softenable material as defined herein, and the support need not be dielectric but can comprise any suitable substrate material as disclosed hereinabove.
  • the migration material may in such cases comprise any suitable material disclosed in U.S. Pat. No. 3,520,68l to William L. Goffe, and hereby incorporated by reference, and can be selected from an extermely broad group, including electrical insulators, electrical conductors, photosensitive material, optically inert material and mixtures thereof.
  • the process steps herein described may be used in imaging. such a member.
  • a removal of the entire migration layer 13 after development including softenable material and migration material 14 remaining in layer 13 in nonmigrated areas together with any photoconductive layer 12 which may be present results in a member extremely useful for making resistive networks, especially where substrate 10 is dielectric.
  • a conductive coating such as, for example, aluminum on the free surface of the dielectric substrate provides capacitors comprising the migrated conductive particles sandwiching the dielectric substrate between the conductive coating. These capacitiors have the conductive coating as a common ground where the coating is continuous.
  • the coating is discontinuous or has discrete portions such as, for example, being applied to the dielectric substrate free surface through a stencil, mask or other suitable technique, the resulting capacitors do not have a common ground so fabricated.
  • the layers 13 & 12, and other layers can be removed by wiping or swabbing the layers with a solvent filled wad 54 or otherwise mechanically or sonically agitating the imaging member in a solvent bath; by use of an airknife while the layers are sufficiently softened; or by use of ajet spray of solvent.
  • These and similar means of removing the entire layer 13, and other entire layers, after development are distinguished from the removal of softenable material 15 as previously described in that the latter operation leaves migration material 14 remaining in-depth atop softenable dielectric layer 11 or layer 12 where layer 12 is employed, in non- 12 migrated areas (i.e., areas where there is no migration out of migration layer 13).
  • This method of forming circuit components can conveniently be carried out by insuring the presence of a sufficiently high concentration of migration material 14 in migration layer 13 relative to the thickness of layer 11 that so much migration material migrates into layer 11 that layer 11 is filled or saturated with the migrated material throughout its thickness where migration into layer 11 occurs.
  • the member in FIG. 1A without the photoconductive layer 12 is prepared in the following manner.
  • the substrate is prepared with an about l/l6 inch thick phenolic sheet, vacuum coated with a thin layer of aluminum that forms a conductor.
  • the softenable dielectric layer 11 which is herein circulated comprises an about 1:1 mixture of a copolymer of n-butylmethacrylate and polystyrene and Piccotex I00, dissolved in toluene.
  • the solution is coated onto the aluminum side of the phenolic sheet to yield an about 6 micron thick layer upon drying.
  • the migration layer 13 is made by dissolving about 2 parts Nirez 1085 in Sohio Odorless Solvent 3440 and adding about 1 part Neo-Spectra Carbon Black available from Columbia Carbon Company.
  • the resulting dispersion is coated upon the layer 11 to yield a thickness of about 3 microns upon drying.
  • the imaging member is electrically latently imaged by having positive charge deposited so that noncharged areas on the surface of migration layer 13 represent a resistive network.
  • the charge creates an electrical field strength across layers 11 and 13 of about 50 volts per micron, using a corona charging device described by Vyverberg in U.S. Pat. No. 2,836,725.
  • the charged member is subjected to trichloroethylene vapors for about 5 seconds thereby softening layers 11 and 13 and allowing the carbon black particles to migrate in charged areas where circulation occurs.
  • the member is then immersed for about 2 seconds in Sohio Odorless Solvent 3440 thereby removing the Nirez 1085 from migration layer 13 and leaving carbon black particles in non-charged areas atop dielectric layer 11 in-depth.
  • the Piccotex in dielectric layer 11 is slightly soluble in the Sohio Odorless Solvent 3440 and consequently wicks up into the interstices of the carbon black particles in non-charged areas and binds them to one another upon drying.
  • the carbon black particles residing on the surface of dielectric layer 11 in non-charged areas are in the configuration of the non-charged areas on the surface of migration layer 13 and form a resistive network.
  • Example II Example I is followed except that the non-charged areas on the surface of migration layer 13 represent capacitive elements of a circuit and the carbon black particles residing on the surface of dielectric layer 11 in non-charged areas form conductive elements which sandwich portions of dielectric layer 11 between corresponding portions of the aluminum conductor coated upon the phenolic sheet, forming capacitors having a common ground.
  • Example I is followed except that the substrate is /4 mil Mylar, polyethlene terephthalate, available from E. I. DuPont de Nemours, and has successively coated upon each side thereof the softenable dielectric and migration layers, respectively, of Example I.
  • Example I is followed but with double corona charging so as to have non-charged areas on the surfaces of both migration layers conform to a first set of elements in a resistivecapacitive network and one side of the member is then exposed to trichloroethylene vapors and Sohio Odorless Solvent 3440 as in Example I to form circuit elements on one side of the member. The member is then discharged using AC corona.
  • Example I Charging as in Example I is again followed so that non-charged areas conform to a second set of elements which when created complete the desired network.
  • the side of the member opposite to that previously exposed to trichloroethylene vapor is now exposed to such vapors and Sohio Odorless Solvent 3440 as in Example I to form the second sets of network elements.
  • Example I and II are followed except that a softenable photoconductive layer 12 is placed between dielectric layer 11 and migration layer 13.
  • the photoconductive layer 12 is coated upon dielectric layer 11 out of a solution of Sohio Odorless Solvent 3440 containing about 2 parts 0.1 micron average diameter phthalocyanine particles and about 3 parts Nirez 1085, to a dried thickness of about 1 micron.
  • the migration layer 13 is then coated upon dried photoconductive layer 12.
  • the member is uniformly charged with the corona charging device of Example I so that the uniformily deposited positive charge on the surface of migration layer 13 creates an electrical field strength of about 50 volts per micron across layers 11, 12 and 13.
  • the photoconductive layer 12 is exposed to a 75 Watt lamp of f/22 at about 1 foot for about 1 second through a transparency which is transparent in the configuration of the resistive network and capacitive elements of Examples I and II, respectively, and opaque in remaining areas.
  • the member is exposed to trichloroethylene vapors as in Example I resulting in migration of carbon black particles in non-exposed areas into the dielectric layer 11.
  • Carbon black particles migrate in exposed areas to the bottom of the migration layer 13 at its interface with photoconductive layer 12 and correspond in configuration to the transparent image of the transparency: a resistive network in Example IV and capacitive elements in Example V are formed.
  • Example III is followed in making a double sided member with the inclusion of softenable photoconductive layer 22 of FIG. 2 (made as in Examples IV and V) in each side of the double sided member.
  • the double sided member is uniformly electrostatically charged on the surfaces of both migration layers with charges of opposite polarity (i.e.; one side positively, the other negatively) and exposed, as in Examples IV and V, on both sides.
  • charges of opposite polarity i.e.; one side positively, the other negatively
  • one side of the member is exposed to a first set of elements in a resistive capacitive network and the other side of the member is exposed to a second set of elements in the same network.
  • both sides of the double sided member are simultaneously exposed to trichloro- 14 ethylene vapors for about 5 seconds. Migration occurs in non-exposed areas into the softenable dielectric layers 21 on each side of the member and in exposed areas down to the interface between migration layers 23 and dielectric layers 21 of FIG. 2.
  • Example I is followed except that the substrate is dielectrical polyvinylidene chloride, sold under the trademark Saran by E. I. DuPont de Nemours, and is coated out of tetrahydrofuran to have a dried thickness of about 6 microns.
  • the softenable dielectric layer 11 of Example I is coated to dry at about 3 in thickness and the softenable migration layer 13 of Example I is coated to dry at about 6 microns in thickness.
  • the layers 1 l and 13 are prepared as :in Example I but the parts are by volume. The member is charged as in example I but so that charged areas of migration layer 13 correspond to the desired resistive network.
  • the carbon black migrates in network configuration into softenable dielectric layer 11 in charged areas and completely fill dielectric layer 11 throughout its thickness where migration into layer 11 occurs.
  • the entire migration layer 13, including carbon black remaining therein, is then removed by swabbing with a cotton ball containing Sohio Odorless Solvent 3440.
  • Example VII is followed except that the charged areas on the surface of migration layer 13 correspond to elements of a capacitive network.
  • the substrate is vacuum coated with aluminum as in Example I but on its free surface
  • the migrated] carbon black form conductive elements which sandwich portions of the dielectric substrate between corresponding portions of the aluminum coating and form capacitors having a common ground.
  • Example III is followed except thatthe thicknesses and ratios of Example. VII are followed in making the double-sided member; the charged areas on the surface of the migration layers correspond to the network elements; and the entire migration layers are removed by swabbing as in Example VII.
  • Examples VII and VIII are followed except that the softenable photoconductive layer of Example IV and V is included; and the member is charged and exposed as in Examples IV and V except the transparency is opaque in the configuration of the resistive network and capacitive elements, respectively, and transparent in remaining areas.
  • the swabbing of Examples VII is continued until the photoconductive layer is removed, in addition to the removal of the entire migration layer.
  • Example VI is followed except that the thicknesses and ratios of Example VII are followed in making the softenable dielectric layer 21 and softenable migration layer 23; the transparencies used in exposing its opaque in the configuration of the desired resistive-capacitive network and transparent in remaining areas. Swabbing as in Example VII is conducted to remove the entire migration and photoconductive layers on both sides of the member.
  • Examples II, V, VIII, respectively, are repeated except that the dielectrical polyvinylidene chloride substrate of Example VII is employed, and is vacuum coated with aluminum through a stencil so that the substrate has a conductive coating on its free surface only in capacitive areas. After processing the member, the capacitors formed do not have a common ground.
  • One modification is to make the circulation referred to herein to occur in a well ordered and defined pattern. This may be accomplished by various mechanical, electrical and/or optical (i.e. by screened exposure) techniques disclosed in U.S. Pat. Nos. 3,436,216; 3,698,893; and 3,719,483. Broadly, the technique is to modulate the electric field across a frostable material spacially related to the natural special response of the material. Notably, many frostable materials are suitable for use in softenable dielectric layer 11.
  • the charge densities capable of initiating circulation and/or deformation may be below the normal respective threshold values for circulating or deforming the member.
  • the charge of the electrical latent image employed in the present invention should be capable of circulating: which means that the charge density is above the respective threshold level, spacially modulated and/or otherwise effectively employed.
  • the circulation mechanism generally requires that the circulation layer be sufficiently thin so that the charge density required to initiate circulation will not cause dielectric breakdown. Further, the resistivity of the circulation layer should be sufficiently great so that ohmic discharge does not occur before elapse of the development time for the imaging member. It has been empirically found that development time for the imaging members disclosed herein can be approximated by the factor N sec/poise where N is the viscosity in poises of the softenable material of the circulation layer.
  • circuit or network includes any conductive elemental component of circuits and networks such as, for example, leads or electrical pathways, a conductive member of a capacitor, a resistor and any other conductive element or sub-element of any desired network.
  • Very fine conductive wire, con ductively coated fibers, foil wrapped threads and other such conductive articles can be used to provide suitable leads between components within the circuit or network. These can be either conveniently threaded through the various softenable layers in their softened state or residing on surfaces thereof, as the process steps chosen and desired circuit or network allow.
  • resistive circuit components can be conveniently tailored to various resistance values for the same conductive migration material by simply varying the thickness of the migration layer have migration material dispersed therein.
  • the resistance for a given material will vary inversely with the thickness of the resistive circuit component formed with the migration material in the migration layer.
  • the resistance will be proportional inversely with the migration layer thickness of migration layers having migration material dispersed therein; for a given loading factor of migration material in migrationlayer.
  • the loading of migration material can be 'increased for a given thickness migration layer.
  • the double sided migration member in FIG. 2 can be employed in making transparencies and can optionally have two differently colored migration materials, one each in each migration layer.
  • both of the entire remaining migration layers and optional photoconductive layers can be removed as herein above described to yield an imaged member comprising a transparent support and a transparent softenable layer on each side of the support having migration material migrated therein in imagewise configuration.
  • the migrated migration material in each of the transparent softenable layer will be correspondingly differently colored.
  • the remaining migration layers after migration imaging can be left in place and images formed as a result of imagewise change in either optical transmission density or optical reflection density, especially in circulation embodiments of the invention.
  • Many of the softenable materials listed above are suitably transparent softenable materials.
  • a method of preparing circuit components comprising;
  • the method of claim 5 further including the step of (d) fusing said fusible, conductive migration particles.
  • said conductive migration material comprises fusible conductive particles, further including the step (e) of fusing said fusible conductive migration particles.
  • the method of claim 8 further including the step of (d) removing the entire remaining migration layer and wherein said at least one of migrated and remaining migration material portions in circuit component configuration is said migrated portion of migration material.
  • step (a) is further provided on its free surface with a second softenable dielectric layer and a second migration layer having conductive migration material and softenable material; further including the subjection of said second softenable dielectric layer and said second migration layer to steps (b) and (c).
  • said charge pattern includes an electrostatic charge level which produces an electrical field strength across said softenable dielectric layer of from about 10 volts per micron to about volts per micron.
  • volume ratio of migration material to softenable material in the migration layer is from about 1:19 to about 1:1.
  • a circuit member comprising:
  • a dielectric substrate upon which said softenable dielectric layer resides said dielectric substrate being provided on its free surface with a discontinuous conductive coating comprising discrete portions, at least one of which discrete portions sandwiches the dielectric substrate between said at least 19 one discrete portion and said at least one electrically conductive circuit component.
  • the member of claim 29 further including conductive migration material residing in depth atop the free surface of said softenable dielectric layer and forming at least one conductive circuit component.
  • the member of claim 39 wherein the ratio of conductive material to fusible insulating material is from about percent to about 95 percent by weight.
  • a circuit member comprising:
  • a softenable migration layer comprising substantially electrically insulating softenable material and electrically conductive migration material forming at least one electrically conductive circuit component therein;
  • said conductive material within the softenable dielectric layer forms at least one conductive circuit component therein, further including means electrically connecting the softenable dielectric layer circuit component with the softenable migration layer circuit component.
  • the member of claim 33 further including a softenable photoconductive layer interpositioned between said dielectric and migration layers.
  • a migration imaging member comprising:
  • a softenable migration layer residing on each of said softenable layers and comprising substantially 20 electrically insulating softenable material and migration material;
  • a softenable photoconductive layer interpositioned between the layer of softenable material and the softenable migration layer on each side of said support.
  • the imaging member of claim 50 wherein said thickness is from about 0.5 micron to about 1 micron.
  • each of said migration layers is from about 0.5 micron to about 6 microns thick.
  • each of said migration layers has a thickness from about 0.5 micron to about 1 micron.
  • each of said layers of softenable material has a thickness form about 1 micron to about 12 microns thick.
  • the imaging member of claim 46 wherein the migration material on one side of said support is differently colored from the migration material on the other side of said support, and wherein said support, layers of softenable material and migration layer softenable material are transparent.
  • a method of preparing circuit components comprising:
  • said softenable dielectric layer, said softenable photoconductive layer and said electrically insulating softenable material capable of having their resistance to migration of migration material decreased sufficiently to allow migration material in depth in said softenable dielectric layer, said softenable photoconductive layer and said electrically insulating softenable material;
  • step of electrically latently imaging further includes charging the imaging member and exposing the photoconductive layer to actinic electromagnetic radiation.
  • said softenable photoconductive layer comprises photosensitive particles dispersed in softenable material.
  • said softenable photoconductive layer has a thickness of from about 0.5 micron to 5 microns.

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US4028101A (en) * 1974-08-22 1977-06-07 Xerox Corporation Migration imaging member employing a surface skin
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US5032478A (en) * 1989-08-21 1991-07-16 E. I. Du Pont De Nemours And Company Photosensitive aqueous developable gold conductor composition
US5032490A (en) * 1989-08-21 1991-07-16 E. I. Du Pont De Nemours And Company Photosensitive aqueous developable copper conductor composition
US5047313A (en) * 1989-08-21 1991-09-10 E. I. Du Pont De Nemours And Company Photosensitive semi-aqueous developable copper conductor composition
US5576129A (en) * 1994-12-09 1996-11-19 Xerox Corporation Migration imaging members
US7492882B1 (en) * 2004-03-01 2009-02-17 Embarq Holdings Company, Llc C2P provisioning late-breaking scenarios

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