US3697408A - Imaging system - Google Patents

Imaging system Download PDF

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Publication number
US3697408A
US3697408A US821255A US3697408DA US3697408A US 3697408 A US3697408 A US 3697408A US 821255 A US821255 A US 821255A US 3697408D A US3697408D A US 3697408DA US 3697408 A US3697408 A US 3697408A
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Prior art keywords
electrode
imaging
blocking
suspension
web
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Expired - Lifetime
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US821255A
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English (en)
Inventor
Gerard T Severynse
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Xerox Corp
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Xerox Corp
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Publication date
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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
    • G03G17/04—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

  • This invention relates in general to imaging systems and more specifically to an improved electrophoretic imaging system.
  • the system improved by this invention is of the type using photosensitive radiant energy absorbing particles believed to bear a charge when suspended in a non-conductive liquid carrier.
  • the suspension of these particles in the carrier is placed in an electroded system to be exposed to an image radiation configuration.
  • An electroded system to be exposed to an image radiation configuration.
  • the particles em ployed in this system migrate in image configuration providing a visual image at one or both of the electrodes between which they are placed.
  • the system employs particles which are photosensitive and which apparently undergo a net charge alteration upon exposure to activating radiation by interaction with one of the electrodes.
  • Various mixtures of two or more difierent colored particles can be used to secure the various colors of images and imaging mixes having different spectral responses. These colors can be used independently or even in subtractive color synthesis. In a monochromatic system the particles will migrate if energy of any wavelength within the panchromatic spectrum of the particle response strikes the particle.
  • an object of this invention to improve electrophoretic imaging systems by eliminating corona arcing between electrodes. Another object of this invention is to improve systems using broad contact zones between relatively moving electrodes. Still another object is to allow use of reuseable or non-reuseable blocking surfaces in broad imaging contact.
  • FIG. 1 is a schematic illustration of an imaging device employing this invention
  • FIG. 2 is a schematic illustration of another embodiment of the invention.
  • FIG. 3 is another schematic illustration of an embodiment of this invention.
  • FIG. 1 a photoelectrophoretic imaging system having an injecting electrode, generally referred to by reference numeral 10, having a transparent glass substrate 12 and an electrically conductive layer 14. Both the glass and the overcoated layer are optically transparent.
  • the structure may be of tin oxide coated on glass which is commercially available under the name NESA glass from Pittsburgh Plate Glass C0. Any other suitable. structure usable within the imaging system is suitable for this invention.
  • Deposited on the injecting electrode is a thin layer 16 of finely divided photosensitive particles dispersed in an insulating liquid carrier. This is the imaging suspension from which a final image is formed.
  • a blocking electrode Adjacent to theelectrode 10 and the suspension 16 thereon is a blocking electrode, generally referred to by the reference numeral 18, which has a blocking layer 20 formed around a plurality of roller guides 22, 24 and 26. These guides and the blocking material layer 20 surrounding them extend the entire width of the electrode 10 and form a tractor type moving device when the rollers are driven by a suitable drive mechanism, for example, motor M-1. This movement causes portions of the blocking layer 20 to lay down and then be picked up across thesurface of the injecting electrode 10.
  • Drive connections for the blocking electrode assembly are of the usual type and wouldbe known to those skilled in the art of making such assemblies.
  • photosensitive refers to the properties of a particle which, once attracted to the. injecting electrode, will reverse its polarity and migrate away from it under the influence of an applied electric field when exposed to activating electromagnetic radiation.
  • injecting electrode for the purpose of this invention refers to the electrode the properties of which apparently inject chargesinto photosensitive materialsactivated by electromagnetic radiation under the influence of an electric field.
  • blocking electrode for the purpose of this invention refers to the property of an electrode which once contacted by activing photosensitive particles will not inject charge into a .sufficient number. of them to cause them to migrate from the blocking electrode surface.
  • suspension may be defined as a system having solid particles dispersed in a solid, liquid or gas.
  • suspensions described for illustrations herein are of the general type having a solid dispersed in a liquid carrier.
  • the blocking electrode assembly has three rollers shown for support and guidance.
  • the outer rollers 22 and 26 are formed of any material though preferably hard and relatively inflexible. Although their electrical characteristics are not critical, it may be desirable to have the outer rollers 22 and 26 formed of conductive material and maintain these rollers at the same electrical level as the conductive surface 14 of the injecting electrode 10. This helps prevent charge build-up on the surface 20 of the blocking electrode.
  • the center roller 24 must contain a conductive core or be made of a conductive material and should contact the lower surface of the blocking material 20 which is ofaa high dielectric type material such as Tedlar, a polyvinyl fluoride commercially available from E. I. du Pont de Nerrrours C0,, Inc.
  • the roller 24 is electrically connected to a potential source 28 through a switch 30. An electric field is produced between the injecting electrode 10 and the conducting roller 24 when the switch 30 is closed. Between the two is the blocking surface 20 and the suspension 16.
  • the electric field is applied in proximity to the roller 24 as the blocking electrode assembly 18 moves across the suspension 16 on the surface of the injecting electrode 10 in the vicinity of the charged roller 24.
  • the movement is in the direction shown by the arrow.
  • the image to be made is formed by a projection system made up of a light source 32, a transparency 34 and a lens 36 positioned to project an image of the transparency at the suspension 16 on the injecting electrode 10.
  • FIG. 2 schematically shows a representation of this invention in a photoclectrophoretic imaging system where- 4 in the improved blocking electrode is in the form of a disposable Web 58.
  • the injecting electrode shown herein generally referred to as electrode 10 is formed as a continuous plate shaped as a cylinder. Around the periphery of the electrode surface 40 are the various stations,
  • a suspension dispensing system generally referred to as 42 and having a container 44 for holding the suspension 16 used for imaging.
  • a conduit 46 brings the suspension to an applicator bar 48 which applies a more or less uniform, thin layer of the suspension 16 on the injecting electrode surface 40.
  • An optical system is pnovided to expose the suspension to activating electromagnetic radiation in the vicinity of the blocking electrode 18.
  • the optical system has an electromagetic radiation source 50 and a transparency 52 which is to be imaged at the interface of the blocking electrode 18 and the injecting electrode 40 through the lens 54 and past mirrors 55 and 56.
  • Any suitable optical system for forming an image in the contact zone 57 being the broad area of contact at the interface of the two electrodes, is suitable for the application shown here.
  • the blocking electrode 18 is formed as a web 58 of a high dielectric material having a resistivity greater than 10 ohm-cm. held on a supply spool 60 to be fed around guide rollers 62 and 64 to a take-up spool 66. Intermediate the guide rollers 62 and 64 which maintain the web 58 adjacent to the cylindrical injecting electrode surface 40 is an electric field generating device.
  • the device shown here is a corona discharge device in the form of a corotron 68 which is electrically connected to a suitable source (not shown) to generate the proper field in close proximity to the corotron 68 between the blocking electrode web 58 and the injecting electrode surface 40 through the suspension 16 maintained therebetween.
  • the corotron or any similar device may generate AC or DC corona to control the potential field at the blocking electrode.
  • the guide rollers 62 and 64 are preferably conductive and are held at the same potential as is the injecting electrode 40. By maintaining both the rollers 62 and 64 at the same potential as the injecting electrode a corona arc bridging the gap between the Web 58 and the surface 40 of the injecting electrode 10 is eliminated.
  • Typical voltages employed in this system for imaging while exposing may be in the range of 300-5000 volts between the electrode surfaces in close proximity to the corotron 68. Since the web 58 is of a high dielectric material and generally non-conductive having a resistivity of 10 ohm-cm.
  • the electrical charge on the web 58 in proximity to the corotron 68 does not-spread to the outer edges of the contact zone 57 between the web and the surface 40 of the injecting electrode 10.
  • the corotron may be shielded to prevent any electric arcing between it and the rollers 62 and 64 even if the voltages and distances are such that arcing may otherwise tend to occur.
  • Imaging of the photoelectrophoretic suspension takes place in the area between the web 58 and surface 40 where there is suflicient electrical field to image under proper exposure conditions. This is the contact zone. Its maximum coverage as shown is delineated by the spacing numbered 57. The field as described, isnarrowly maintained within the interface of the web 58 and the surface 40 so that it does not extend to the positions where the electrodes separate beyond the spacing referred to as 57.
  • the take-up spool 66 is driven by suitable means to insure the proper velocity of the web 58 so that it moves in the direction shown in rolling contact with the surface 40 of the injecting electrode 10.
  • the image to be formed into the final copy is designated by numeral 72 and is carried by the cylindrical injecting electrode to contact an adhesive web 74 which is pressed against the injecting electrode surface by rollers 76 and 78 also functioning to guide the adhesive web 74.
  • the image 72 is transferred to the adhesive web 74 which maintains it thereon.
  • the transferred image then may be fixed in place by lamination or, as shown by the figure, through a suitable fixing chamber 80 which may supply heat or some other means that will insure fixing of the image.
  • FIG. 3 shows another embodiment representing a modification of the embodiment of FIG. 2 which uses a disposable web 82 as the surface of the blocking electrode 18.
  • the web is made to traverse the injecting electrode formed as a Hat plate.
  • this embodiment does not give the benefit of continuous imaging as shown in FIG. 2, it does illustrate the use of a disposable blocking electrode surface.
  • the operation of the apparatus in this figure is similar to 'FIG. 2 in that the high dielectric blocking surface 82 moves in rolling contact with the suspension 16 on the conductive surface 14 of the injecting electrode 10.
  • the guide rollers 84 and 86 maintaining contact between the electrode surfaces in moving contact zone may be conductive although this is not absolutely required. Nonethe less, they are preferably maintained at the same potential as the conductive surface 14 of the injecting electrode 10 in order to insure that there be no corona arcing between the two surfaces.
  • the commutator bar 88 is electrically connected to a high voltage source to provide approximately between 300 5000 volts relative to the injecting electrode 10. It also insures close pressure contact in the high field contact zone. Exposure is achieved in the manner discussed in FIG. 1.
  • the commutator bar 88 is positioned to maintain the electrical field in a limited area within the contact zone of the blocking surface 82 and the conductive surface 14 of the injecting electrode 10. The positioning is such that there is insufficient field at the edges between the electrodes to permit air ionization or corona arcing.
  • An apparatus for photoelectrophoretic imaging comprising:
  • separation support means for guiding said web away from the imaging suspension, said support means being positioned to cause said web to remain in contact with the layer of imaging suspension from said contacting support means to said separation support means;

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  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Molecular Biology (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Electrochromic Elements, Electrophoresis, Or Variable Reflection Or Absorption Elements (AREA)
  • Devices For Indicating Variable Information By Combining Individual Elements (AREA)
US821255A 1969-05-02 1969-05-02 Imaging system Expired - Lifetime US3697408A (en)

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US82125569A 1969-05-02 1969-05-02

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JP (1) JPS4840096B1 (enrdf_load_html_response)
DE (1) DE2021386A1 (enrdf_load_html_response)
GB (1) GB1312733A (enrdf_load_html_response)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3844779A (en) * 1968-12-12 1974-10-29 Xerox Corp Photoelectrophoretic imaging method employing a belt electrode
US3989366A (en) * 1975-04-24 1976-11-02 Xerox Corporation Photoelectrophoretic imaging apparatus having a device for increasing the friction force between webs

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS57197718U (enrdf_load_html_response) * 1981-06-11 1982-12-15

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3844779A (en) * 1968-12-12 1974-10-29 Xerox Corp Photoelectrophoretic imaging method employing a belt electrode
US3989366A (en) * 1975-04-24 1976-11-02 Xerox Corporation Photoelectrophoretic imaging apparatus having a device for increasing the friction force between webs

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DE2021386A1 (de) 1970-11-12
JPS4840096B1 (enrdf_load_html_response) 1973-11-28
GB1312733A (en) 1973-04-04

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