US2573881A - Method and apparatus for developing electrostatic images with electroscopic powder - Google Patents

Method and apparatus for developing electrostatic images with electroscopic powder Download PDF

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Publication number
US2573881A
US2573881A US57962A US5796248A US2573881A US 2573881 A US2573881 A US 2573881A US 57962 A US57962 A US 57962A US 5796248 A US5796248 A US 5796248A US 2573881 A US2573881 A US 2573881A
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United States
Prior art keywords
powder
image
charge
plate
charged
Prior art date
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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US57962A
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English (en)
Inventor
Lewis E Walkup
Donald L Fauser
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Battelle Development Corp
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Battelle Development Corp
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Publication date
Application filed by Battelle Development Corp filed Critical Battelle Development Corp
Priority to US57962A priority Critical patent/US2573881A/en
Priority to GB5565/50A priority patent/GB693905A/en
Priority to FR1017567D priority patent/FR1017567A/fr
Priority to CH286142D priority patent/CH286142A/fr
Priority to DEB2979A priority patent/DE903414C/de
Application granted granted Critical
Publication of US2573881A publication Critical patent/US2573881A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/22—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20
    • G03G15/28—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 in which projection is obtained by line scanning
    • G03G15/30—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 in which projection is obtained by line scanning in which projection is formed on a drum
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
    • G03G15/08—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer
    • G03G15/0801—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer for cascading
    • 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

  • This invention relates to a method and apparatus for developing electrostatic images with electroscopic powder, with reference particularly to the general type of apparatus in which an insulating image layer on a, conductive plate is electrostatically charged and the image then developed by dusting thereon an electroscopic powder which is subsequently transferred and aflixed to a suitable transfer sheet or support, and it has for its purpose to afford a procedure by which the background areas or non-image portions of the plate carrying the image layer are maintained substantially free from electroscopic powder, which adheres only to the image area, thus resulting in a copy or reproduction in which the background areas as well as the image areas correspond closely to the original subject, so as to produce a faithful copy with background areas free from undesirable shadows or darkened portions.
  • the invention is particularly applicable to processes involving the use of developing materials consisting of a combination of finely divided pigmented electroscopic powder with a coarser carrier material, the carrier material being triboelectrically charged with a polarity opposite to that of the electroscopic powder upon frictional engagement therewith and acting to retain the electrosccpic powder which is attracted to and surrounds the particles of carrier material, and if the charge on the non-image areas of the plate has a greater attractive force for the electroscopic powder particles than the charge on the carrier material has, the electroscopic powder particles are likely to be attracted to and held by the non-image areas on the plate even though such non-image areas are of a conductive character to drain oil the major part of the electrostatic charge except over the insulating image areas, and it is a particular object of the invention to impose a further electrostatic charge on the non-image areas of the plate or to surround said areas with an electrostatic field such that the charge on the non-image areas will have a polarity opposite to the charge on the image areas and
  • a further purpose of the invention is to provide a practical, economical, and efiiclent construction in the form of an electrode or other electrostatic field-creating instrumentality that is adaptable to a continuous electro-printing machine or to other mechanism for applying electroscopic powder to a charged image layer, whereby the powder will be applied evenly and uniformly over the image areas of the plate and the non-image areas will be left substantially free of electroscopic powder.
  • Fig. 1 is a diagrammatic sectional view illustrating one embodiment of the invention as incorporated in a continuous electro-printing apparatus, and
  • Fig. 2 is a diagrammatic view illustrating the action of an electrode in creating an electrostatic field adjacent to and on a plate when electroscopic powder is applied to the latter.
  • the invention is applicable to the method disclosed in copending application of Lewis E. Walkup and Edward N. Wise, Serial No. 24,674, filed May 1, 1948, and to the copending application of Roland M. Schafiert, Serial No. 55,816, filed October 21, 1948, which includes a rotating drum on which is mounted a conductive printing plate carrying an insulating image layer, combined with means for applying electroscopic powder by gravity to the image layer as the drum rotates, after which the powder image is transferred to a continuous strip of paper or other material that 3 is continuously fed along in contact with the drum at a point beyond the powder dusting area, the paper strip and drum being constantly charged by suitable charging instrumentalitles which maintains an electrostatic charge constantly on the insulating image layer and also holds the paper strip in contact with the drum at the point where the image is transferred to the paper by electrostatic action.
  • Fig. 1 which discloses such a mechanism
  • I designates the rotating drum whilq 2 is the conductive printing plate suitably mounted thereon and carrying the insulating image layer, which it is not necessary to show for purposes of the present invention
  • 3 designates a discharge receptacle from which electroscopic powder gravitates over the inclined bottom 4 to fall onto the drum and travel downwardly by gravity, the surplus electroscopic powder which is not retained by the charged image layer on the drum falling into the receptacle 5.
  • 8 designates the continuous paper strip that is fed from a roll I through a path adjacent to the drum'as shown and from which it is deflected by the stripping fingers 8 after which the paper travels downwardly over an inclined chute or guide 9 onto a receiving roll H.
  • I 2 designates heating elements that act to fuse the powder image onto the paper strip as it travels downwardly over the chute 9, while l3 designates corona discharge needles or other suitable devices for applying an electrostatic charge onto the paper strip 6 and onto the insulating image of the drum.
  • l4 designates any suitable cleaning instrumentaliiw for removing from the drum surplus electroscopic powder after each transfer operation, thus preparing the charged image layer to receive a fresh supply of electroscopic powder and additional charging units such as shown at i and 16 may be employed if desired to impose additional charges on the insulating layer of the drum, although these charging units and their location form no part of the present invention which will now be described in detail.
  • an electrode i! preferably curved as shown to conform to the curvature of the drum and located between the powder chamber wall 18 and the surface of the drum, being spaced at a distance of substantially 1.25" from the surface of the drum.
  • the electrode ll is in the form of a plate having a length preferably that of the drum I and extending around the drum from a point immediately beneath the inclined bottom 4 of the powder discharge receptacle to a point below that at which the powder falls away from the drum, so that the electrode substantially covers the entire area over which powder is in moving contact with the drum, and the electrode I!
  • the electrode ll may consist of a solid -sheet, a screen, a series of ⁇ wires, or a series of points suspended or located over the area described, or near the plate surface during development, the electrode ll being connected by conductor IS with any suitable source of potential supply to create the desired electake place and the effect produced by the electrode l1.
  • the electrode I1 is likewise charged negatively by applying a suitable potential, and such negative charge on electrode l1 induces a positive charge as indicated on the non-image areas of the plate 22, shown at either side of the image area 25.
  • the electroscopic powder that produces the powder image by adherence to the image area 25 is charged positively by triboelectric action of the carrier material to which the electroscopic powder particles adhere until separated therefrom by the stronger attractive force of the charged insulating image layer 2!. Since the non-image areas of the plate are electrostatically charged positively by the electrode H by induction, such positive charges repel the positively charged electroscopic powder particles, and thus any tendency of the electroscopic powder to adhere to the non-image or background areas of the plate is effectively overcome.
  • the electrode ll having a charge of the same polarity as the insulating image layer exerts an attractive force on the electroscopic powder and to this extent may reduce the density of the powder image, but this is not of appreciable significance when proper voltages are applied to the electrode, and by suitably controlling the spacing between the electrode and the insulating image layer and the potential applied to the electrode, the electrostatic field between the electrode and the printing plate can be adjusted as desired and the relative action of the electroscopic powder on the insulating image layer and on the non-image areas of the plate can be regulated and controlled to give the proper and desired effect.
  • the method of developing an electrostatic image on a charged insulating image layer supported on a conductive plate, and which conductive plate extends across the background area oi the image which consists in applying developing powder to the charged image layer while maintaining an electrical field, produced by a, potential having a polarity the same as that of the charge on the image layer and opposite to that of the charge on the developing powder, over the area of the plate to induce a charge in the background area opposite in polarity to the charge in the image area while the powder is applied, whereby Powder having the same charge as the background area is repelled from the background area.
  • the method 'of developing an electrostatical- 1y charged image on an insulating image layer supported on a conductive plate which extends across a background area, which consists in applying developing powder to the charged image layer and inducing on the non-image areas of the plate an electrical charge having a polarity opposite to that of the charge on the image layer and the same as the charge on the developing powder to repel powder from the background area, said last-mentioned charge being produced by an electrical field applied to the plate while developing.
  • An electroprinting apparatus comprising in combination, a plate consisting of an electrically conductive movable supporting backing plate carrying a nonconducting charged image layer, said backing plate extending across the background area of the image, means for charging said image layer, powder-applying means for presenting to the plate charged developing powder having a polarity opposite to the polarity of the charged image layer, background charge inducing electrode mounted in spaced relation from the image layer in the image-powder attraction zone to effect an electric field in said attraction zone to induce in the background area a charge of the same polarity as the polarity of the powder. whereby said powder is simultaneously repelled from the background area and attracted to the image area.
  • An electroprinting mechanism for transferring a charged powder image to a surface comprising an electroprinting plate consisting of an electrically conducting movable support which forms the background area of the printing plate having an image layer of electrically nonconducting material thereon, said image layer being charged electrically with a charge having a po- ⁇ larity opposite to that of the polarity of the charge of the powder to be transferred, powder-applying means located adjacent to the movable support acting to flow a stream of developer powder charged with a charge of polarity opposite to that of the charge on the insulating image layer over the plate, said powder adhering to the image layer electrostatically to form a powder image, an electrical field-producing electrode charged with the same polarity as the image area mounted in spaced relation to the plate surface with the stream of powder flowing between the electrode and the plate, said electrical field being such as to effect an induced charge of the same polarity as that of the powder in the background area to repel the powder from the background area, and, electrostatic means for transferring said charged powder image to
  • moving support means are provided to move a conductive printing plate which forms the background area of the plate having an insulating image on its printing surface past a charging station
  • electrical means at said station for placing a charge of a first polarity on said insulating image
  • powder-applying means at a sequential station to deposit a powder carrying a charge of second polarity on said image surface

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Printing Methods (AREA)
  • Printers Or Recording Devices Using Electromagnetic And Radiation Means (AREA)
  • Combination Of More Than One Step In Electrophotography (AREA)
US57962A 1948-11-02 1948-11-02 Method and apparatus for developing electrostatic images with electroscopic powder Expired - Lifetime US2573881A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
US57962A US2573881A (en) 1948-11-02 1948-11-02 Method and apparatus for developing electrostatic images with electroscopic powder
GB5565/50A GB693905A (en) 1948-11-02 1950-03-06 Method and apparatus for developing electrostatic images with electroscopic powder
FR1017567D FR1017567A (fr) 1948-11-02 1950-03-14 Procédé et appareil de développement des images électrostatiques
CH286142D CH286142A (fr) 1948-11-02 1950-03-17 Procédé de développement d'une image par voie électrique.
DEB2979A DE903414C (de) 1948-11-02 1950-04-09 Verfahren und Einrichtung zur Entwicklung elektrischer Ladungsbilder

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US57962A US2573881A (en) 1948-11-02 1948-11-02 Method and apparatus for developing electrostatic images with electroscopic powder

Publications (1)

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US2573881A true US2573881A (en) 1951-11-06

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US57962A Expired - Lifetime US2573881A (en) 1948-11-02 1948-11-02 Method and apparatus for developing electrostatic images with electroscopic powder

Country Status (5)

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US (1) US2573881A (fr)
CH (1) CH286142A (fr)
DE (1) DE903414C (fr)
FR (1) FR1017567A (fr)
GB (1) GB693905A (fr)

Cited By (77)

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US2684901A (en) * 1950-12-19 1954-07-27 Haloid Co Image transfer device
US2684902A (en) * 1951-11-23 1954-07-27 Haloid Co Image transfer mechanism for electrostatically adhering images
US2701765A (en) * 1951-06-18 1955-02-08 Haloid Co Xerographic fusing apparatus
US2752833A (en) * 1950-07-15 1956-07-03 Carlyle W Jacob Apparatus for reproduction of pictures
US2761416A (en) * 1953-01-02 1956-09-04 Battelle Development Corp Development mechanism for electrostatic images
US2777418A (en) * 1954-02-08 1957-01-15 Haloid Co Apparatus for developing a powder image on a xerographic plate
US2779306A (en) * 1955-03-25 1957-01-29 Ibm Electroscopic toner metering device
US2781705A (en) * 1953-10-29 1957-02-19 Herbert E Crumrine Paper handling mechanism for xerographic copying machine
US2784109A (en) * 1950-09-18 1957-03-05 Haloid Co Method for developing electrostatic images
US2784694A (en) * 1955-02-08 1957-03-12 Haloid Co Segmented development electrode
US2792752A (en) * 1953-07-01 1957-05-21 Rca Corp Method of and means for controlling light
US2796832A (en) * 1952-03-27 1957-06-25 Harris Seybold Co Plate dampening means
US2807233A (en) * 1954-03-29 1957-09-24 Ibm Electrophotographic printing machine
US2807703A (en) * 1956-06-14 1957-09-24 Ibm Xerographic image fixing apparatus
US2807704A (en) * 1956-06-14 1957-09-24 Ibm Xerographic image fixing apparatus
US2808023A (en) * 1955-01-03 1957-10-01 Haloid Co Apparatus for developing electrostatic latent image
US2824813A (en) * 1952-05-12 1958-02-25 Haloid Co Method for developing electrostatic latent images
US2826634A (en) * 1951-04-14 1958-03-11 Atkinson Method and means for magnetic reproduction of pictures
US2834132A (en) * 1954-12-14 1958-05-13 American Type Founders Co Inc Electrostatic applying and holding device
US2838997A (en) * 1953-10-30 1958-06-17 Rca Corp Electrostatic image copying method
US2843084A (en) * 1955-06-16 1958-07-15 Haloid Co Xerographic apparatus with endless development electrode
US2844123A (en) * 1955-06-16 1958-07-22 Haloid Xerox Inc Belt development electrode
US2862646A (en) * 1955-02-18 1958-12-02 Haloid Xerox Inc Powder particle aerosol generator
US2872338A (en) * 1955-04-18 1959-02-03 Haloid Xerox Inc Electrophotographic developing process
US2880696A (en) * 1956-05-02 1959-04-07 Haloid Xerox Inc Apparatus for developing an electrostatic latent image
US2887023A (en) * 1951-11-26 1959-05-19 Rca Corp Electrostatic printer
US2894799A (en) * 1956-08-23 1959-07-14 Gen Telephone Lab Inc High speed recorder system
US2895847A (en) * 1953-12-21 1959-07-21 Battelle Development Corp Electric image development
US2900515A (en) * 1956-03-16 1959-08-18 Edward L Criscuolo Radiography by gas ionization
US2912586A (en) * 1957-11-01 1959-11-10 Haloid Xerox Inc Xerographic charging
US2914403A (en) * 1955-05-17 1959-11-24 Rca Corp Electrostatic printing
US2932690A (en) * 1956-09-21 1960-04-12 Addressograph Multigraph Apparatus for image reproduction
US2932278A (en) * 1955-05-03 1960-04-12 Sperry Rand Corp Single print magnetic printer
US2937912A (en) * 1954-05-14 1960-05-24 Cymmer Thomas Device for making a record and displaying it
US2943908A (en) * 1954-08-02 1960-07-05 Gen Electric Apparatus for recording and portraying a visible magnetic image
US2952241A (en) * 1955-02-03 1960-09-13 Haloid Xerox Inc Developer electrode for electrophotographic apparatus
US2955052A (en) * 1954-05-05 1960-10-04 Haloid Xerox Inc Method of forming a raised image
US2955938A (en) * 1955-08-01 1960-10-11 Haloid Xerox Inc Xerography
US2965573A (en) * 1958-05-02 1960-12-20 Haloid Xerox Inc Xerographic developer
US2968552A (en) * 1956-10-01 1961-01-17 Haloid Xerox Inc Xerographic apparatus and method
US2969463A (en) * 1957-05-03 1961-01-24 Plastics-treating apparatus
US2986466A (en) * 1955-12-06 1961-05-30 Edward K Kaprelian Color electrophotography
US2996573A (en) * 1957-05-13 1961-08-15 Dick Co Ab Television projection system employing electrostatic printing
US3004860A (en) * 1957-04-24 1961-10-17 Xerox Corp Induction powder transfer
US3011474A (en) * 1959-02-06 1961-12-05 Harold O Ulrich Xerographic development electrode apparatus
US3033765A (en) * 1958-06-06 1962-05-08 Eastman Kodak Co Photographic production of electrically conducting silver images
US3052564A (en) * 1954-12-20 1962-09-04 Ibm Printing with magnetic ink
US3053962A (en) * 1960-08-01 1962-09-11 Xerox Corp Xerographic fusing apparatus
US3094909A (en) * 1958-05-29 1963-06-25 Szekeres Janos Reproduction apparatus
US3117891A (en) * 1960-09-26 1964-01-14 Xerox Corp Xerographic apparatus
US3160091A (en) * 1959-05-14 1964-12-08 Xerox Corp High speed xeroprinter and method therefor
US3205354A (en) * 1960-02-13 1965-09-07 Azoplate Corp Electrothermographic reproduction process
US3260612A (en) * 1961-07-14 1966-07-12 Eastman Kodak Co Thermographic recording process and heat-sensitive elements therefor
US3306198A (en) * 1963-12-04 1967-02-28 Continental Can Co Electrostatic printing process
US3320879A (en) * 1965-10-08 1967-05-23 Monsanto Co Ink delivery system employing vibrating wires
US3332328A (en) * 1965-03-01 1967-07-25 Xerox Corp Xerographic developer seal and process
US3349676A (en) * 1965-04-02 1967-10-31 Xerox Corp Xerographic development electrode apparatus
US3363552A (en) * 1965-10-20 1968-01-16 Continental Can Co Methods and apparatus for minimizing screen patterns in xerography, electrostatic screen process and other forms of printing
US3412710A (en) * 1966-10-11 1968-11-26 Xerox Corp Cleanup electrode
US3424131A (en) * 1964-09-30 1969-01-28 Xerox Corp Electroded cascade development system
US3443517A (en) * 1967-01-04 1969-05-13 Xerox Corp Electrostatic duplicating system employing relief printing plate
US3536485A (en) * 1965-07-01 1970-10-27 Xerox Corp Xerographic plate supported by a mandrel
US3622314A (en) * 1967-07-01 1971-11-23 Fuji Photo Film Co Ltd System for repulsion development in electrophotography
US3649262A (en) * 1968-12-31 1972-03-14 Xerox Corp Simultaneous development-cleaning of the same area of an electrostatographic image support surface
US3719169A (en) * 1971-05-07 1973-03-06 Xerox Corp Plural electrode development apparatus
US3807997A (en) * 1971-05-07 1974-04-30 Xerox Corp Plural electrode development methods for latent electrostatic images
US3833364A (en) * 1968-11-18 1974-09-03 Xerox Corp Method of developing electrostatic image charge
US3857560A (en) * 1973-07-23 1974-12-31 Xerox Corp Adhesive paper pick-off system
US3869910A (en) * 1973-06-18 1975-03-11 Xerox Corp Diagnostic test device for developer materials
US3888666A (en) * 1971-12-22 1975-06-10 Rank Xerox Ltd Reversal developing method using photoconductive developing electrode
US3893800A (en) * 1973-11-14 1975-07-08 Rank Xerox Ltd Backside heating and fixing apparatus in an electronic photograph duplicator
US3918403A (en) * 1973-11-23 1975-11-11 Xerox Corp Corona transfer mechanism
US3960556A (en) * 1973-03-01 1976-06-01 Addressograph Multigraph Corporation Constant current toner transfer
DE1797613B1 (de) * 1965-03-01 1979-09-20 Rank Xerox Ltd Vorrichtung zum Entwickeln elektrostatischer Ladungsbilder
US4318608A (en) * 1977-01-05 1982-03-09 Payne John M Portable electrostatic photocopier
US4350435A (en) * 1980-04-04 1982-09-21 Eastman Kodak Company Copy contrast and density control
US5213042A (en) * 1992-02-25 1993-05-25 The Nuventures Foundation Printing process and apparatus

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US3138458A (en) * 1955-09-30 1964-06-23 Minnesota Mining & Mfg Electrophotography
DE1058840B (de) * 1956-03-19 1959-06-04 Zindler Lumoprint Kg Durchlaufentwicklungs- und Fixiervorrichtung fuer blattfoermige fotoleitende Schichttraeger
DE1059287B (de) * 1956-03-28 1959-06-11 Zindler Lumoprint Kg Durchlaufkopier- und Entwicklungsgeraet
DE1058841B (de) * 1956-04-24 1959-06-04 Zindler Lumoprint Kg Vorrichtung zur Herstellung von Kopien auf fotoleitenden Schichten
US3039388A (en) * 1958-01-02 1962-06-19 Harris Intertype Corp Printing press and sheet control device therefor
US3311490A (en) * 1958-09-23 1967-03-28 Harris Intertype Corp Developing electrostatic charge image with a liquid developer of two immiscible phases
DE1192045B (de) * 1959-04-18 1965-04-29 Wilhelm Uhrig Elektrophotographisches Verfahren zur Herstellung von Bildern
US3105770A (en) * 1960-04-15 1963-10-01 Xerox Corp Cascade development improvement

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Cited By (77)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2752833A (en) * 1950-07-15 1956-07-03 Carlyle W Jacob Apparatus for reproduction of pictures
US2784109A (en) * 1950-09-18 1957-03-05 Haloid Co Method for developing electrostatic images
US2684901A (en) * 1950-12-19 1954-07-27 Haloid Co Image transfer device
US2826634A (en) * 1951-04-14 1958-03-11 Atkinson Method and means for magnetic reproduction of pictures
US2701765A (en) * 1951-06-18 1955-02-08 Haloid Co Xerographic fusing apparatus
US2684902A (en) * 1951-11-23 1954-07-27 Haloid Co Image transfer mechanism for electrostatically adhering images
US2887023A (en) * 1951-11-26 1959-05-19 Rca Corp Electrostatic printer
US2796832A (en) * 1952-03-27 1957-06-25 Harris Seybold Co Plate dampening means
US2824813A (en) * 1952-05-12 1958-02-25 Haloid Co Method for developing electrostatic latent images
US2761416A (en) * 1953-01-02 1956-09-04 Battelle Development Corp Development mechanism for electrostatic images
US2792752A (en) * 1953-07-01 1957-05-21 Rca Corp Method of and means for controlling light
US2781705A (en) * 1953-10-29 1957-02-19 Herbert E Crumrine Paper handling mechanism for xerographic copying machine
US2838997A (en) * 1953-10-30 1958-06-17 Rca Corp Electrostatic image copying method
US2895847A (en) * 1953-12-21 1959-07-21 Battelle Development Corp Electric image development
US2777418A (en) * 1954-02-08 1957-01-15 Haloid Co Apparatus for developing a powder image on a xerographic plate
US2807233A (en) * 1954-03-29 1957-09-24 Ibm Electrophotographic printing machine
US2955052A (en) * 1954-05-05 1960-10-04 Haloid Xerox Inc Method of forming a raised image
US2937912A (en) * 1954-05-14 1960-05-24 Cymmer Thomas Device for making a record and displaying it
US2943908A (en) * 1954-08-02 1960-07-05 Gen Electric Apparatus for recording and portraying a visible magnetic image
US2834132A (en) * 1954-12-14 1958-05-13 American Type Founders Co Inc Electrostatic applying and holding device
US3052564A (en) * 1954-12-20 1962-09-04 Ibm Printing with magnetic ink
US2808023A (en) * 1955-01-03 1957-10-01 Haloid Co Apparatus for developing electrostatic latent image
US2952241A (en) * 1955-02-03 1960-09-13 Haloid Xerox Inc Developer electrode for electrophotographic apparatus
US2784694A (en) * 1955-02-08 1957-03-12 Haloid Co Segmented development electrode
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Also Published As

Publication number Publication date
DE903414C (de) 1954-02-04
FR1017567A (fr) 1952-12-12
GB693905A (en) 1953-07-08
CH286142A (fr) 1952-10-15

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