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US3083117A - Process of developing electrostatic images - Google Patents

Process of developing electrostatic images Download PDF

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Publication number
US3083117A
US3083117A US741017A US74101758A US3083117A US 3083117 A US3083117 A US 3083117A US 741017 A US741017 A US 741017A US 74101758 A US74101758 A US 74101758A US 3083117 A US3083117 A US 3083117A
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United States
Prior art keywords
powder
image
paper
transfer
developer
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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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US741017A
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English (en)
Inventor
Schmiedel Ulrich
Fischer Henning
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Classifications

    • 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
    • G03G9/09—Colouring agents for toner particles
    • G03G9/0928—Compounds capable to generate colouring agents by chemical reaction
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G7/00—Selection of materials for use in image-receiving members, i.e. for reversal by physical contact; Manufacture thereof
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S101/00—Printing
    • Y10S101/29—Printing involving a color-forming phenomenon
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S101/00—Printing
    • Y10S101/37—Printing employing electrostatic force

Definitions

  • the developed, but not fixed, image has to be transferred onto another material, most generally paper. Further such transfer is practiced with the image produced on the semi-conductive layer carried over onto materials, such as oflset plates, fabric, transparent sheet material, plastics etc.
  • the powder image mostly a mixture of resin and carbon black, has to be fixed either by burning in (baking) or melting onto the support, or a strong adhesion to the support is provided by means of solvents.
  • a powder which preferably consists of a resin/carbon black mixture and a carrier.
  • this carrier consists of pulverized glass or metal.
  • the powder image is fixed by means of heat.
  • the required heat fixing temperature lies above the melting point of the powder, which means the temperature is so high that the materials used, especially paper, is likely to become damaged, or the powder image becomes crumbly. Considerable heat is produced in the appa-.
  • transfer and fixation of the imageor in case the image is transferred onto another material, transfer and fixationare effected by chemical reactions, in which the developer powder, i.e. the powder used for the development of the latent electrostatic image, takes an essential part.
  • the developer powder contains one or more reactive chemical groups, which chemically react with one reactive group or several of such reactive groups contained either in the electrophotographic layer, or, in case the image is transferred, in the transfer material, whereby a visible image is formed. To cause this reaction, the reactive groups must be brought into contact with each other. If the image is to be transferred, the method according to thepresent invention has the further advantage that transfer and fixation are effected in one step.
  • the reaction may be initiated or speeded up by the application of warmth, humidity, gases or pressure.
  • the developing powder must be capable of being electrostatically attracted by the electrostatic latent image.
  • the powder has to be charged, which may be effected, e.g., by mixing it in known manner with glass balls. In other cases, such additional charging may be omitted. This fact may be of importance with regard to the quantity of powder to be attracted. For particular situations, attraction and retention by the electrostatic charge image of a great quantity of powder, or of a small quantity of powder may be desirable. If several transfer images are to be produced from one single charge image, a greater quantity of powder may be successively reacted with several transfer papers.
  • reactants may either form as the result of the reaction a firmly adherent dyestulf or colored chemical compound, or the reactant contained in the developer powder may be an ingredient of a colored compound which reacts with the reactant contained in the contacting layers only for the purpose of fixation. If one of the reactants is contained in the electrophotographic semi-conductive layer, the further step of fixing can be omitted, because in consequence for the intended reaction.
  • the image adheres to the surface and is in a visible state.
  • several reactants may be contained in the developer powder itself, which then participate in the reaction.
  • the substances required for the preparation of the electrophotographic layer may contain or represent the reactants in question.
  • the inorganic salts and/or organic compounds known to be photoconductive substances may contain or represent the necessary reactants.
  • the substances used as binders, e.g. silicone resins, may be used for this purpose.
  • the developer .powder should be selected with regard 'to a fine grain size.
  • the special rate of fine distribution of the grains may vary, as can be seen from the examples.
  • the dyestuff image obtained by a chemical reaction may be in- 'flueneed in its color and density by varying the physical and chemical conditions, such as heat, pressure and humidity, which initiate the chemical reaction, when choosing a certain reactant.
  • developer powder the essential substance of which is a compound containing both reactive groups necessary After the electrostatic development, both reactive groups are caused to react with each other by physical-chemical influences, such as heat,
  • the reaction product being characterized in that it adheres to the photoelectrical layer. If the image is to be transferred, the physical-chemical influences should be exerted at the very moment, when the transfer material contacts the developer powder adhering loosely to the electrophotographic layer.
  • the above mentioned compound has an orange-yellow color. Upon heating, the compound decomposes, while turning deep red. When a mild alkali such as sodium carbonate, sodium stearate, or sodium phosphate is added,
  • the red color is considerably intensified.
  • the transfer material can also be soaked with said alkali in the form of a solution or a suspension. A slight moistening of the transfer material with acetone is of advantage.
  • a developer powder the essential constituent of which is a compound which is capable of splitting off a part under the influence of physical-chemical methods (heat, pressure, moisture, etc.), the split product adhering firmly to the photoelectrical layer, or in case of transfer to the transfer material.
  • metal salts of sulphur substituted carbamic acid e.g. cobalt salts, bismuth salts or iron salts
  • they split off the sulfide of the respective metal the color of which is characteristic and which is able to adhere firmly to paper.
  • the reaction temperature can be lowered considerably, which is of special advantage when fixing the image.
  • developer substances can also be transferred onto the surface of a second support (transfer sheet) in a manner known per se, and then be treated as described above.
  • a further method is to choose as the essential substance of the developer powder, a chemical compound which also appears in an isomeric form or several isomeric forms. It has been surprisingly found when using one isomeric form of the compound as a developer powder, that after development, this isomeric form can be converted by means of physical-chemical methods (heat, pressure, moisture, etc.) into its isomer or one of its several isomeric forms and that the isomer formed in this way adheres firmly to the electrophotographic layer, or in case of transfer, to the transfer material. If the developed image is to be transferred, the physical-chemical influence is applied when the developer powder contacts the transfer material, as has already been mentioned above.
  • a transfer is desired when using one of the above mentioned methods, it has been found to be of advantage to apply to the transfer material a substance, e.g. a colloid or a synthetic substance, which receives the reaction product and provides a betteradhesiveness.
  • a substance of this kind may also be applied to the electrophotographic material or be coated onto the support together with the photoelectrical insulating mass, to the extent the electrophotographic properties are not lost thereby.
  • the chemical reaction can be initiated by the influence of gases or vapors. It has now been found that the substance inidating the reaction can also be added in the form of a solution. It has proved advantageous to wipe over the developed image with a cotton pad .Which has been dampened or soaked with this solution. In this case the reaction and the fixing must take place rapidly enough to avoid blurring of the developed image.
  • the transfer paper can not only be coated with a layer containing one of the reactants, but that it is also possible for the purpose of the invention to soak the transfer paper with a solution containing one or more reactants.
  • both surfaces of the paper can be used for transfer, and when transferring an image it is not necessary to watch which side of the prepared material is placed against the developer powder.
  • the reactant or reactants can be added in suitable concentration to the paper-mass used in making the paper.
  • both surfaces of the transfer paper treated as described above can be used as image-reciving surfaces if the paper is made of specially suitable raw materials and certain reactants are used.
  • This two-sided use of transfer paper can be considered if the chemical reaction takes place close to the surface of the transfer-paper and the thus for-med reaction product remains fixed to the reaction zone and does not pass through the paper. It has been found that this is possible in some cases without taking special precautions. In some other cases care must be taken that the degree of humidity in the paper is not too high, and above all, not too much reactive developer powder must be allowed to be transfered.
  • the quantity of powder (developer powder) adhering electrostatically to the surface of the semi-conductive layer depends on the charge of the semi-conductive layer as well as the charge of the powder resulting from known triboelectric or friction effects. But if the control of these quantities of electrical charge seems to be too difiicult the quantity of the reactive developer powder can be diminished by mixing the reactive developer powder with an indifferent substance which should, if possible, have the same electrostatic properties as the reactive powder.
  • the above stated problem concerning the moisture content can be solved by regulating the degree of moisture of a sponge or the like which moistens the surface of the paper in order to release the chemical reaction with the reactant con tained in the developer powder, which is transferred immediately afterwards.
  • the sponge or a like body can, for example, be pulled through a trough containing water, or in some rare cases alcohol or other solvents, and then be given the most suitable degree of moisture by means of a doctor-knife which exerts a variable pressure on the sponge.
  • the chemical reaction takes place in some cases only in the presence of, e.g. a certain quantity of moisture or, in other cases, of heat or pressure, it is possible to hold the reactants in admixture with each other in the developer as long as no moisture, heat or pressure is applied and, as a consequence, no reaction of the reactants can take place.
  • the surface of the transfer paper is moistenedand is caused to contact the developer powder mixture adhering to the semi-conductive layer, immediate reaction occurs only on the surface of the moistened paper and the reaction mixture remains on the surface of the transfer paper.
  • reactants are chosen which form a compound insoluble in the original solvent (mostly water) which reaction product, in addition, remains adhering to the surface of the paper and does not diffuse through the paper, the transfer process can be repeated on the opposite face of the paper so that a double-sided copy can be obtained.
  • reaction in question can also be caused by application of heat as already mentioned.
  • the transfer paper is warmed to a suitable temperature prior or during its contact with the developer powder mixture adhering to the electrostatic paper.
  • reaction can be caused by pressure. This pressure must prevail at the moment of contact between the developer powder mixture and the transfer paper.
  • the desired effect can be obtained by conducting the transfer paper and the semiconductor paper which already carries the developer powder mixture in the form of an image, through a pair of pressure-rolls, for example.
  • the transfer paper may be coated on both sides with the soiution of the reactants; but it is obvious that the production of such paper is more complicated.
  • barytic paper which had been treated with a 10% ammonium ferric sulfate solution was used.
  • the iron salt of the substituted dithiocarbamic acid obtained by reaction was also of a deep brownish-black color.
  • the transfer material was produced by coating a paper base with a saturated alcoholic solution of gallic acid and subsequent drying. Before contacting it with the iron stearate adhering to the ZnO-paper, it had to be wetted with an aqueous alcohol. The neutral black color was then obtained by the formation of the iron salt of the gallic acid. By heating the transfer material, reaction could be speeded up.
  • a diazo compound of the amino carbazole as described in the German patent specification No. 523,259 is mixed with glass balls in the ratio of 4:96.
  • the latent electrophotographic image is developed with the above mentioned diazo compound.
  • it is moistened with a solution of flmaphthol, borax and water. The image is obtained immediately.
  • Example 1 A mixture described in Us. patent specification No. 2,487,034, Example 1, comprising 2,8-dihydroxynaphthalene-6-sulfonic acid, N-phenyl-aniline-p-diazonium acid sulfate, citric acid, thiourea and zinc chloride is mixed with glass balls in the ratio of about 4:96. The mixture thus obtained is then poured over the latent elec- 'trophoto graphic image. The image is rendered visible and fixed mto ammonia vapor.
  • a mixture comprising the zinc chloride double salt of the diazo compound from 5-amino-2-benzoylamino-1,4-diethoxy benzene and primary sodium phosphate according to German patent specification No. 684,334 is mixed with glass balls in the ratio of 4:96 and then poured over the electrophotographic latent image.
  • a transfer paper is coated with phloroglucinol. Subsequently it is slightly moistened with a solution containing sodium chloride, sodium acetate and tartaric acid and is then contacted with the powdered image. The visible colored image is obtained on this second surface.
  • Example 6 can also be executed by incorporating phloroglucinol, finely distributed in a colloid, for example a watersoluble colloid such as the sodium salt of alginic acid, into the electrophotographic layer, or by coating the electrophotographic layer with such phloroglucinol-colloid combination. Powdering of the latent electrostatic image is executed as described by bringing it v01, g 0.25 KHSO, g 20.00 KgSgOs g H2O ml 100.00
  • the developer which may be mixed in a proportion of 25:1 with glass balls, forms a fine powder and is attracted by the still electrostatically charged areas of the semi-conductive layer (ZnOJayer).
  • the prepared transfer paper is moistened. shortly before use and brought into slight contact with the powdered semi-conductive layer. Reaction takes place immediately. During the drying-process or the slightly moistened paper the color shadeanilin'e black has been formed-becomes still somewhat deeper. The reaction time and the drying time can be shortened by passing the developed transfer paper adjacent a heat-source.
  • the VCl serves as a catalyst, the KHSQ, adjusts the pH-value, and the K S O acts'as an oxidizing agent.
  • the aniline hydrochloride (or aniline sulfate) can be mixed with glass-balls.
  • the transfer paper is soaked in or coated with the above aqueous solution. 'After slightly moistening the paper, reaction to a deep black dye-stufi' (black-green) takes place.
  • the K Cr O serves as an oxidizing agent, the CuSO as a catalyst and the KHSO, for the regulation of the pH-value.
  • the dry developer mixture can be applied with or without glass balls.
  • the transfer paper is coated with the aniline solution.
  • amines that can be used in the manner of the above examples are p-amino-p-hydroxy-diphenyl-amine. p-dimethyl-amino-p-hydroxy-diphenyl-amine, and p-arnino-methyLdiphenyl-amine.
  • chlorates, chromates and permanganates can also be used, and copper ions in general as well as iron ions and OsO, are further examples of suitable'catalysts.
  • transfer paper a paper was used which was first soaked in a 10% sodium sulfide solution andthen dried. Shortly before its use, ie before contacting it with the copper salt adhering to the zinc oxide layer, the transfer paper was slightly moistened on its surface by means of a sponge. A deep black color was formed, the color being due to the copper sulfide formed.
  • the process of developing electrostatic images and fixing them on a support which process includes the steps of applying powdered iron stearate to an electrostatic image to cause the powder to electrostatically adhere to the charged portions of the image to form a powder image, and then contacting the powder image with a transfer sheet wet with an alcoholic solution of gallic acid to cause the iron stearate of the powder image to "react with the gallic acid and form a black reaction product adherently held on the transfer sheet in the shape of the powder image.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Non-Silver Salt Photosensitive Materials And Non-Silver Salt Photography (AREA)
  • Photoreceptors In Electrophotography (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
  • Color Printing (AREA)
  • Paper (AREA)
  • Developing Agents For Electrophotography (AREA)
US741017A 1957-06-14 1958-06-10 Process of developing electrostatic images Expired - Lifetime US3083117A (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DESCH22287A DE1057449B (de) 1957-06-14 1957-06-14 Verfahren zur Entwicklung, UEbertragung und Fixage elektrophotographischer Bilder
DESC023103 1957-11-15
DESC023104 1957-11-15

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US3083117A true US3083117A (en) 1963-03-26

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DE (2) DE1057449B (de)
GB (1) GB898354A (de)

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3234018A (en) * 1960-03-18 1966-02-08 Lumoprint Zindler Kg Method for developing copies using electrophotographic layers
US3253913A (en) * 1960-10-13 1966-05-31 Eastman Kodak Co Process for color electrophotography
US3262806A (en) * 1961-12-16 1966-07-26 Azoplate Corp Three component magnetic developer for electrophotographic purposes and method for using it
US3272644A (en) * 1963-07-31 1966-09-13 Dennison Mfg Co Development of latent electrostatic images with crystalline toners
US3285741A (en) * 1961-04-19 1966-11-15 Agfa Gevaert Nv Process for developing electrostatic latent images
US3350202A (en) * 1964-10-27 1967-10-31 Union Carbide Corp Method of xerographically photosensitizing planographic printing plates
US3365324A (en) * 1963-03-18 1968-01-23 Bernice B Blake Solution development of xerographic latent images
US3373019A (en) * 1964-05-21 1968-03-12 Bell & Howell Co Method and apparatus for producing images
US3381596A (en) * 1964-11-20 1968-05-07 Minnesota Mining & Mfg Electrophotographic copysheet
US3392018A (en) * 1962-04-11 1968-07-09 Commw Of Australia Xerochemical development of electrostatic images
US3510336A (en) * 1965-08-12 1970-05-05 Gaf Great Britain Ltd Reflex copying method
US3510297A (en) * 1966-05-05 1970-05-05 Ibm Process for producing negative transparencies
US3622368A (en) * 1967-08-22 1971-11-23 Ricoh Kk Method for developing electrostatic latent images by utilizing coupling reaction
US3653885A (en) * 1966-10-31 1972-04-04 Xerox Corp Process of stabilizing a migration image comprising selenium particles
EP0066955A3 (en) * 1981-05-22 1983-09-21 Appleton Papers Inc. Dielectric record material
US4681828A (en) * 1986-09-02 1987-07-21 Eastman Kodak Company Method of chemical electrographic image amplification using chemically active toner particles
US5212526A (en) * 1991-11-27 1993-05-18 Xerox Corporation Process and apparatus for transferring and fusing an image to a recording medium
AU768108B2 (en) * 2000-09-14 2003-12-04 Immunotech Multifunctional reagent for erythrocytes

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL268867A (de) * 1960-09-02
DE1249089B (de) * 1962-04-04 1967-08-31
GB1420430A (en) * 1971-11-15 1976-01-07 Canon Kk Image-receiving sheet for electrophotography and related processes
DE2248191C2 (de) * 1972-10-02 1981-10-08 Canon K.K., Tokyo Verfahren zum Entwickeln eines elektrophotographisch erzeugten latenten Bildes zu einem farbigen Tonerbild
EP0706094B1 (de) * 1994-10-03 1999-12-22 Agfa-Gevaert N.V. Elektro(stato)graphisches Verfahren, das reaktive Toner verwendet

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2028619A (en) * 1935-03-14 1936-01-21 Justin J Mccarthy Method of obtaining fingerprints
US2487034A (en) * 1946-03-20 1949-11-01 Gen Aniline & Film Corp 2.8-dihydroxynaphthalene-6-sulfonic acid as the azo component for diazotype prints
US2730456A (en) * 1953-06-30 1956-01-10 Ncr Co Manifold record material
US2735785A (en) * 1953-07-30 1956-02-21 Process of electrostatic printing
US2735784A (en) * 1953-07-30 1956-02-21 Process of electrostatic printing
US2761416A (en) * 1953-01-02 1956-09-04 Battelle Development Corp Development mechanism for electrostatic images
US2910351A (en) * 1955-01-03 1959-10-27 Gen Electric Method of making printed circuit
US2953470A (en) * 1957-06-27 1960-09-20 Ncr Co Method for electrostatic printing

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2028619A (en) * 1935-03-14 1936-01-21 Justin J Mccarthy Method of obtaining fingerprints
US2487034A (en) * 1946-03-20 1949-11-01 Gen Aniline & Film Corp 2.8-dihydroxynaphthalene-6-sulfonic acid as the azo component for diazotype prints
US2761416A (en) * 1953-01-02 1956-09-04 Battelle Development Corp Development mechanism for electrostatic images
US2730456A (en) * 1953-06-30 1956-01-10 Ncr Co Manifold record material
US2735785A (en) * 1953-07-30 1956-02-21 Process of electrostatic printing
US2735784A (en) * 1953-07-30 1956-02-21 Process of electrostatic printing
US2910351A (en) * 1955-01-03 1959-10-27 Gen Electric Method of making printed circuit
US2953470A (en) * 1957-06-27 1960-09-20 Ncr Co Method for electrostatic printing

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3234018A (en) * 1960-03-18 1966-02-08 Lumoprint Zindler Kg Method for developing copies using electrophotographic layers
US3253913A (en) * 1960-10-13 1966-05-31 Eastman Kodak Co Process for color electrophotography
US3285741A (en) * 1961-04-19 1966-11-15 Agfa Gevaert Nv Process for developing electrostatic latent images
US3262806A (en) * 1961-12-16 1966-07-26 Azoplate Corp Three component magnetic developer for electrophotographic purposes and method for using it
US3392018A (en) * 1962-04-11 1968-07-09 Commw Of Australia Xerochemical development of electrostatic images
US3365324A (en) * 1963-03-18 1968-01-23 Bernice B Blake Solution development of xerographic latent images
US3272644A (en) * 1963-07-31 1966-09-13 Dennison Mfg Co Development of latent electrostatic images with crystalline toners
US3373019A (en) * 1964-05-21 1968-03-12 Bell & Howell Co Method and apparatus for producing images
US3350202A (en) * 1964-10-27 1967-10-31 Union Carbide Corp Method of xerographically photosensitizing planographic printing plates
US3381596A (en) * 1964-11-20 1968-05-07 Minnesota Mining & Mfg Electrophotographic copysheet
US3510336A (en) * 1965-08-12 1970-05-05 Gaf Great Britain Ltd Reflex copying method
US3510297A (en) * 1966-05-05 1970-05-05 Ibm Process for producing negative transparencies
US3653885A (en) * 1966-10-31 1972-04-04 Xerox Corp Process of stabilizing a migration image comprising selenium particles
US3622368A (en) * 1967-08-22 1971-11-23 Ricoh Kk Method for developing electrostatic latent images by utilizing coupling reaction
EP0066955A3 (en) * 1981-05-22 1983-09-21 Appleton Papers Inc. Dielectric record material
US4681828A (en) * 1986-09-02 1987-07-21 Eastman Kodak Company Method of chemical electrographic image amplification using chemically active toner particles
US5212526A (en) * 1991-11-27 1993-05-18 Xerox Corporation Process and apparatus for transferring and fusing an image to a recording medium
AU768108B2 (en) * 2000-09-14 2003-12-04 Immunotech Multifunctional reagent for erythrocytes

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Publication number Publication date
GB898354A (en) 1962-06-06
DE1057449B (de) 1959-05-14
DE1072884B (de) 1960-01-07

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