US3706553A - Transfer of images to a nonconductive substrate - Google Patents

Transfer of images to a nonconductive substrate Download PDF

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US3706553A
US3706553A US886838A US3706553DA US3706553A US 3706553 A US3706553 A US 3706553A US 886838 A US886838 A US 886838A US 3706553D A US3706553D A US 3706553DA US 3706553 A US3706553 A US 3706553A
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image
imaging
conductive
mylar
images
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Elsie L Menz
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ELSIE L MENZ
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ELSIE L MENZ
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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
    • G03G13/14—Transferring a pattern to a second base
    • G03G13/18—Transferring a pattern to a second base of a charge pattern
    • 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
    • G03G17/04—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 photoelectrophoresis

Definitions

  • the present invention relates in general to the transfer of images from an image bearing surface to an image receiving surface and more particularly to a method for accomplishing such transfer by means of a rearrangement of static electric charges and coulombic attraction.
  • Various imaging processes are known wherein a thin film of material is deposited on a substrate or image bearing surface to provide a contract to said surface in image configuration. Due to the process steps employed in producing such images, the substrate on which the image is first formed is, in some cases, not the substrate which is most durable, useful or desirable.
  • an imaging layer is prepared by a coating of a layer of electrically photosensitive imaging material onto a substrate.
  • the imaging layer comprises a photosensitive material such as metal-free phthalocyanine dispersed in a cohesively weak insulating or dielectric binder. This coated substrate is called the donor. When needed, the imaging layer is rendered cohesively weak.
  • the process step of weakening the imaging layer is termed activation and in most cases the imaging layer is activated by contacting it with a swelling agent, solvent, or partial solvent for the imaging layer or by heating the layer.
  • a receiver sheet is laid over the surface of the imaging layer and an electric field is applied across the imaging layer while it is exposed to a pattern of light and shadow representative of the image to be reproduced.
  • the imaging layer fractures along the lines defined by the pattern of light and shadow to which the imaging layer has been exposed.
  • Part of the imaging layer is transferred to one of the sheets while the remainder is retained on the other sheet so that a positive image, that is, a duplicate of the original is produced on one sheet while a negative image is produced on the other.
  • the apparatus employed to produce images by means of the manifold imaging process more conveniently uses donor and receiver sheets which are not well suited for the end use of the image.
  • xerography Another example of prior art imaging processes wherein the transfer of imaging material from one surface to another is employed is xerography.
  • an image formed by a toner on a carrier is transferred from a dielectric surface containing an electrostatic image to an image receiving substrate or medium in order to provide a usable copy.
  • the machinery or apparatus commonly employed to perform this function is now common and notably complex.
  • Another object of this invention is to provide a method of transferring dielectric imaging material from an image bearing surface to an image receiving surface without complex equipment.
  • Another object of this invention is to provide images of improved quality which have been transferred from an image bearing substrate to an image receiving medium.
  • a process whereby a releasable image residing on an electrically insulating medium is transferred to an electrically non-conductive image receiving medium.
  • Such transfer is accomplished by charging the surface of the image and the medium upon which the image resides. The thus charged image is then contacted with. the non-conductive receiving medium thus forming an image transfer set.
  • a conductive path is then provided between the outer or exposed surfaces of the image bearing medium and the image receiving medium. This is normally accomplished by contacting the exposed surfaces with conductive plates which are interconnected by a conductive wire. By means of the conductive path, both surfaces are brought to the same potential and the releasable image transfers to the image receiving medium.
  • Upon separation of the set there is provided a high quality image on the receiving substrate or medium. Included in the term image are portions of images and defined or artistic patterns of dielectric material on a substrate.
  • the image is electrically charged and such charge is held by the imaging material until after the transfer is accomplished.
  • the process of this invention is particularly adapted for use in transferring images wherein the imaging material is electrically insulating so as to maintain an electric charge for at least a brief period of time.
  • a wide variety of insulating materials can thus be employed in the process of this invention.
  • Insulating materials such as polyethylene, polypropylene, polyamides, polymethacrylates, polyacrylates, polyvinylchlorides, polyvinylacetates, polystyrene, polythioloxanes, chlorinated rubber, polyacrylonitrile, epoxies, phenolics, hydrocarbon resins and other natural resins such as rosin derivatives as well as mixtures and copolymers of the above materials can be employed.
  • Particularly preferred images to be transferred according to the process of this invention are those comprising insulating materials which retain a charge and which are or can be rendered.
  • Such materials include microcrystalline waxes such as: Sunoco 1290, Sunoco 5825, ,Sunoco 985, all available from Sun Oil Co.; Paraflint RG, available from the Moore and Munger Company; parafiin waxes such as: Sunoco 5512, Sunoco 3425, available from Sun Oil Co.; Sohio Parowax, available from Standard Oil of Ohio; waxes made from hydrogenated oils such as: Capitol City 1380 wax, available from Capitol City Products, Co., Columbus, Ohio; Caster Wax L2790, available from Baker Caster Oil Co.; Vitikote L-340, available from Duro Commodities; polyethylenes such as: Polyethylene DYJT, Polyethylene DYLT, polyethylene DYT, all available from Union Carbide Corp.; Marlex TR 822, Marlex 1478, available from Phillips Petroleum Co.; Epolene C- 13, Epolene C-lO, available from Eastman Chemical Products, Co.; Poly
  • the surface of the insulating image materials and the supporting surface of the image bearing medium are electrically charged to the extent required to transfer the image.
  • the amount of charge will vary depending in part upon the dielectric constant, polarity, of the charge and thickness of the image material. It will also vary depending upon the dielectric constant and thickness of the image bearing and image receiving media.
  • lower voltages can be employed such as from about 200 to about 400 volts.
  • higher voltages are employed ranging up to an amount less than the electrical breakdown strength of the image bearing medium.
  • a transfer voltage is applied across the image material and the image receiving medium.
  • Such voltage has a minimum value which varies with different materials and must exist in order to effect transfer.
  • the transfer voltage is calculated according to the following formula:
  • V a voltage constant for the image material
  • K dielectric constant of the image material
  • K dielectric constant of the image bearing substrate
  • D thickness of image bearing medium D
  • D thickness of image material
  • the calculated transfer voltage is 4,000 volts where the image material voltage constant is 240 volts.
  • the activation step may take many forms such as heating the imaging layer thus reducing the adhesion or applying a substance to the surface of the imaging material or including a substance in the imaging material which substance lowers the adhesive strength of the imaging material with respect to the image bearing medium.
  • the substance so employed is termed an activator.
  • the activator should have a high resistivity so as to prevent electrical breakdown of the transfer set. Accordingly, it will generally be found to be desirable to purify commercial grades of activators so as to remove impurities which might impart a higher level of conductivity. This may be accomplished by running the fluids through a clay column or by employing any other suitable purification technique.
  • the activator may consist of any suitable material having the aforementioned properties.
  • the term activator shall be understand to include not only materials which are conventionally termed solvents but also those which are partial solvents, swelling agents or softening agents for the imaging material.
  • the activator can be applied at any convenient point in the process prior to separation of the sandwich.
  • the activator have a relatively low boiling point so that fixing of the image on the image receiving medium can be accomplished upon evaporation of the activator. It is desirable that fixing of the image be accomplished quickly with mild heating at most. It is to be understood, however, that the invention is not limited to the use of these relatively volatile activators.
  • very high boiling point non-volatile activators including silicone oils such as dimethyl-polysiloxanes and very high boiling point long chain aliphatic hydrocarbon oils ordinarily used as transformer oils such as Wemco-C transformer oil, available from Westinghouse Electric Co., have also been successfully utilized in the imaging process.
  • Typical activators include Sohio Odorless Solvent 3440, an aliphatic (kerosene) hydrocarbon fraction, available from Standard Oil Co.
  • Sohio Odorless Solvent 3440 is preferred because it is odorless, nontoxic and has a relatively
  • the image bearing medium useful in the process of this invention is one which retains an electric charge for at least a short period of time and are described herein as electrically insulating. While many non-conductive materials usable as image receiving media can be classified as insulating, materials useful as image bearing media have greater electrical resistance and are thus termed electrically insulating. Typically insulating materials have a resistivity above about 10 ohm-ems. at normal temperatures. Typical examples of such materials include polyethylene, polypropylene, polyethylene terephthalate, cellulose acetate, paper, plastic coated paper such as polyethylene coated paper, vinyl chloride-vinylidene chloride copolymers and mixtures thereof. Mylar (a polyester formed by the condensation reaction between ethylene glycol and terephthalic acid available from E. I. du Pont de Nemours & Co., Inc.) is preferred because of its durability and excellent insulative properties.
  • the image receiving medium useful in the process of this invention may comprise any suitable electrically nonconductive material.
  • nonconductive is intended to mean those materials having a resistivity greater than about ohm-ems. at normal temperatures.
  • Typical non-conductive materials include those listed above as image bearing media and, in addition, include metal impregnated plastics such as Stabilene film, available from Keuffel and Esser Co.
  • the exterior surfaces of the transfer set made up of an image bearing medium, the imaging material and an image receiving medium are brought to the same potential. The most common means of achieving such balance is by backing the image bearing medium with an electrically conductive layer and connecting the conductive layer to a similarly conductive layer which is backing the image receiving medium. The transfer set is then separated while the two conductive layers are electrically interconnected or the set can be separated after removing the conductive layers.
  • Static charges can be imposed upon dielectric layers by means known to the art as by contacting the image and image bearing medium with an electrically charged electrode.
  • the layer may be charged using corona discharge devices such as those described in US. Pat. No. 2,588,699 to Carlson, US. Pat. 2,777,957 to Walkup, US. Pat. 2,885,556 to Gundlach or by using conductive rollers as described in US. Pat. 2,980,834 to Tregay et al. or by frictional means as described in US. Pat. 2,297,691 to Carlson or other suitable apparatus.
  • the conductive layers employed may comprise any suitable conductive material and may be flexible or rigid. Typical conductive materials include metals such as aluminum, brass, steel, copper, nickel, zinc etc. Also, metallic coatings on plastic substrates, rubber rendered conductive by the inclusion of a suitable material therein and the like can be employed. Conductive rubber is preferred because of its flexibility. Transparent conductive electrodes such as tin oxide coated glass may be employed but are not required as the transfer of the image does not require light. Obviously, if photoconductive material is employed in the process the electrical charge may be lost if operated in the presence of light.
  • FIGS. la and lb are expanded in order to facilitate the explanation of the process of this invention, it is to be understood that in actual operation the elements of the image transfer sandwich are in contact with each other in the order shown in FIGS. la and 1b.
  • FIG. la there is provided releasable imaging material 2 sandwiched between electrically insulating image bearing medium 4 and electrically non-conductive image receiving medium 6.
  • the sandwich resides between con-,
  • FIG. 1b illustrates the imaging material 2 adhering to the image receiving medium 6 leaving image bearing medium 4 free of imaging material.
  • a commercial, metal-free phthalocyanine is first purified by acetone extraction to remove organic impurities. Since this extraction step yields the less sensitive beta crystalline form, the x-form is obtained by the procedure described in Example I of US. Pat. 3,357,989.
  • the xform phthalocyanine thus pioduced is used'to prepare the imaging layer according to the following procedure: 5 grams of Sunoco 1290, a microcrystalline wax with a melting point of 178 F. is dissolved in cc. of reagent grade petroleum ether heated to 50 C. and quenched by immersing the container in'cold water to form small wax crystals.
  • the receiver sheet is then lifted up and the phthalocyanine wax layer is activated with one quick brush stroke of a wide camels hair brush saturated with Sohio Odorless Solvent.
  • the receiver sheet is then lowered back down and a roller is rolled slowly once over the closed manifold set with light pressure to remove excess activator.
  • the positive terminal of an 8,000 volt DC. power supply is then connected to the NESA coating in series with a 5,500 megohm resistor and the negative terminal is connected to the black opaque electrode and grounded.
  • a white incandescent light image is projected upward through the NESA glass using a Wollensak 90 mm., 1 4.5 enlarger lens with illumination of approximately 2.5 foot-candle applied for .1 second for a total incident energy of .25 foot-candle second.
  • the receiver sheet is peeled from the set with the potential source still connected.
  • the small amount of activator present evaporates within a second or so after separation of the sheets yielding a pair of excellent quality images with a duplicate
  • Each of the positive images produced as described above residing on the two mil Mylar image-bearing medium are placed on 1 mil thick Mylar immediately after being produced.
  • the 1 mil thick Mylar is resting upon a sheet of aluminum and a second sheet of aluminum is laid upon the Mylar image-bearing medium. A short length of 14 gauge copper wire equipped with spring clamps on each end is then attached one end to each aluminum sheet. Immediately after attaching the clips, the Mylar image bearing medium and the Mylar image receiving medium are separated by hand. Each of the four images produced as described above are transferred totally to the Mylar receiver leaving the original image bearing Mylar sheet substantially free of image material. The images on the Mylar receiver are fixed by heating the imaging material slightly to remove excess activator which was originally applied to the imaging material during their production by means of a manifold imaging process. All of the images thus transferred retain the density and resolution of the image originally produced on the Mylar image bearing medium.
  • Example V An image is first prepared by means of the photoelectrophoretic color imaging process as described in US. Pat. 3,384,565 by preparing an 8% by weight suspension including equal amounts of the following pigments: Watchung Red B, a barium salt of 1-(4-methyl-5'-chloroazobenzene-2-sulphonic acid)-2-hydroxy-3-naphthoic acid 0.1. No. 15865; Monolite Fast Blue GS, the alpha form of metal-free phthalocyanine, OJ. No. 74100; and, 1-cyano-2,3-phthaloyl-7,8 benzopyrrocoline as synthesized according to the first technique given for its synthesis on page 1215 of the Mar.
  • Watchung Red B a barium salt of 1-(4-methyl-5'-chloroazobenzene-2-sulphonic acid)-2-hydroxy-3-naphthoic acid 0.1. No. 15865
  • Monolite Fast Blue GS the alpha form of metal-free phthalocyanine
  • the trimix is subjected to an electric field by placing the sheet pigment side up on the conductive surface of a glass plate and connecting the conductive surface of the glass plate in series with a switch, a potential source and a conductive center of a roller having a coating of baryta paper on its surface.
  • the roller is approximately 2 /2 inches in diameter.
  • a full color positive photographic transparency is projected through the glass plate onto the trimix by placing the transparency between the suspension and a white light source as the roller is moved across the surface of the coated glass plate.
  • the roller is held at a negative potential of (4,000) volts with respect to the conductive glass plate.
  • the roller is passed over the Mylar 3 times and cleaned after each pass.
  • Example VI A black imaging layer useful in the manifold imaging process is prepared by combining about 5 grams of 8 x-form phthalocyanine with about 5 grams Algol Yellow GC, 1,2,5,6-di-(C)C'-diphenyl (thiazole-anthraquinone, OJ. No. 67300, available from General Dyestuffs Corporation), and about 2.8 grams of purified Watchung Red B, 1-(4'-methyl-5-chloro-2'-sulfonic acid) azobenzene-Z- hydroxy-3-naphthoic acid, C.I. No. 15865, available from E. I.
  • du Pont de Nemours & Co. about 8 grams of Sunoco Microcrystalline Grade 5825 having an ASTM melting point of 151 F., available from Sun Oil Company and about 2 grams Parafiint RG, a low molecular weight paraffinic material available fiom the Moore & Mung er Company, New York, N.Y., and about 320 ml. of petroleum ether (-120 C.) and about 14 ml. of Sohio Odorless Solvent 3440 are placed with the mixed pigments in a glass jar containing /2 inch flint pebbles. The mixture is then milled by revolving the glass jar at about 70 r.p.m. for about 16 hours.
  • the mixture is then heated for approximately 2 hours at about 45 C. and allowed to cool to room temperature.
  • the paste-like mixture is then coated in subdued green light on 1 mil thick Mylar by means of a #22 wire wound drawdown rod to produce a coating weight of about .27 gram per square foot.
  • the thus formed imaging layer on the Mylar is employed in the manifold imaging process with a conductive aluminum sheet as a receiver.
  • the voltage applied during imaging and subsequent separation of the donor and receiver sheets is 3.5 kv./mil.
  • a positive image is thus produced on the Mylar and with the residual voltage on the image material and the Mylar sheet the image is contacted with a sheet of 2 mil Tedlar having a dielectric constant of 9, and backed with a conductive metal layer.
  • the Mylar image bearing medium has a dielectric constant of 3.25.
  • a conductive rubber sheet is laid over the Mylar and electrical contact is made with the conductive sheet backing the Tedlar.
  • the Mylar together with the conductive rubber sheet is pulled from the Tedlar leaving the image formerly residing on the Mylar now residing on the Tedlar sheet.
  • Example VII Another image is made by means of the manifold imaging process employing an imaging layer prepared as described in Example VI.
  • the voltage employed during imaging and subsequent separation of the donor and receiver sheet is 4 kv./mil.
  • the 1 mil Mylar receiver is laid on another sheet of 1 mil Mylar which has been wetted with Sohio Odorless Solvent 3440.
  • a conductive rubber sheet is placed on top of the Mylar bearing the image and connected to a conductive plate backing the wetted Mylar sheet. After assuring firm contact of the image with the wetted Mylar sheet, the rubber electrode and the Mylar receiver is removed leaving the image on the wetted Mylar sheet.
  • a right-reading copy can be obtained by the process of this invention by employing an appropriate number of mirrors in the optical system employed to produce the image.
  • the use of mirrors in producing the image will provide a compensating factor which produces a right-reading positive image when transferred in accordance with the process of this invention.
  • a method of making and transferring a dielectric image from an electrically insulating-image bearing medium to an electrically non-conductive image receiving medium, said receiving medium having a resistivity of at least ohms-centimeters which comprises the steps of:
  • (A) forming an image by a method comprising steps (1) providing an electrically photosensitive imaging layer sandwiched between a donor layer being electrically insulating, said imaging layer and a receiver layer, at least of one said layers being structurally fracturable in response to the combined effects of an applied electrical field and exposure to an electromagnetic radiation to which said layer is sensitive;
  • a method of claim 1 further including step of rendering said imaging layer structurally fracturable in response to the combined etfects of an applied electric field and exposure which said layer is an activator.
  • the method of claim 1 further including the steps of rendering said image releasable from said insulating layer by applying thereto an activator.
  • the method of claim 9 further including the step of rendering said image releasable by applying thereto an activator selecte d from the group consisting of solvents, partial solvents, swelling and softening agents for said image material.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Molecular Biology (AREA)
  • Photoreceptors In Electrophotography (AREA)
  • Electrophotography Using Other Than Carlson'S Method (AREA)
US886838A 1969-12-22 1969-12-22 Transfer of images to a nonconductive substrate Expired - Lifetime US3706553A (en)

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US (1) US3706553A (enrdf_load_stackoverflow)
AR (1) AR203811A1 (enrdf_load_stackoverflow)
BE (1) BE760456A (enrdf_load_stackoverflow)
CA (1) CA947368A (enrdf_load_stackoverflow)
DE (1) DE2063324A1 (enrdf_load_stackoverflow)
FR (1) FR2074442A5 (enrdf_load_stackoverflow)
GB (1) GB1339577A (enrdf_load_stackoverflow)
NL (1) NL7018483A (enrdf_load_stackoverflow)
SE (1) SE371305B (enrdf_load_stackoverflow)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3837883A (en) * 1969-12-22 1974-09-24 Xerox Corp Image transfer process
US3857722A (en) * 1972-04-10 1974-12-31 Australia Res Lab Method for electrostatic duplication
US3960556A (en) * 1973-03-01 1976-06-01 Addressograph Multigraph Corporation Constant current toner transfer
US4172905A (en) * 1973-01-26 1979-10-30 The Commonwealth Of Australia Transferring xerographic images
WO1991004517A1 (en) * 1989-09-07 1991-04-04 Coulter Systems Corporation Toning method and member for electrostatography

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3837883A (en) * 1969-12-22 1974-09-24 Xerox Corp Image transfer process
US3857722A (en) * 1972-04-10 1974-12-31 Australia Res Lab Method for electrostatic duplication
US4172905A (en) * 1973-01-26 1979-10-30 The Commonwealth Of Australia Transferring xerographic images
US3960556A (en) * 1973-03-01 1976-06-01 Addressograph Multigraph Corporation Constant current toner transfer
WO1991004517A1 (en) * 1989-09-07 1991-04-04 Coulter Systems Corporation Toning method and member for electrostatography

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Publication number Publication date
AR203811A1 (es) 1975-10-31
SE371305B (enrdf_load_stackoverflow) 1974-11-11
BE760456A (fr) 1971-06-17
NL7018483A (enrdf_load_stackoverflow) 1971-06-24
FR2074442A5 (enrdf_load_stackoverflow) 1971-10-01
DE2063324A1 (enrdf_load_stackoverflow) 1971-06-24
GB1339577A (en) 1973-12-05
CA947368A (en) 1974-05-14

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