US3871329A - Development electrode - Google Patents

Development electrode Download PDF

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Publication number
US3871329A
US3871329A US297779A US29777972A US3871329A US 3871329 A US3871329 A US 3871329A US 297779 A US297779 A US 297779A US 29777972 A US29777972 A US 29777972A US 3871329 A US3871329 A US 3871329A
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US
United States
Prior art keywords
mesh
accordance
electrodes
electrode
sheet
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
Application number
US297779A
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English (en)
Inventor
John M Anemaet
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Dennison Manufacturing Co
Original Assignee
Dennison Manufacturing Co
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Dennison Manufacturing Co filed Critical Dennison Manufacturing Co
Priority to US297779A priority Critical patent/US3871329A/en
Priority to AU61237/73A priority patent/AU6123773A/en
Priority to DE19732351717 priority patent/DE2351717A1/de
Priority to FR7336770A priority patent/FR2203101B1/fr
Priority to CA183,355A priority patent/CA992304A/en
Priority to JP48115375A priority patent/JPS49134338A/ja
Priority to GB4824673A priority patent/GB1452520A/en
Application granted granted Critical
Publication of US3871329A publication Critical patent/US3871329A/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
    • G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
    • G03G15/10—Apparatus for electrographic processes using a charge pattern for developing using a liquid developer
    • G03G15/108—Apparatus for electrographic processes using a charge pattern for developing using a liquid developer with which the recording material is brought in contact, e.g. immersion or surface immersion development

Definitions

  • An electrostatic photocopy apparatus uses a liquid developer for developing the electrostatic image on an image bearing sheet.
  • the structure of the developing means utilizes upper and lower electrode means connected to the same electric potential between which the sheet passes in a pool of developer liquid.
  • Both electrodes in a preferred embodiment are in the form of metallic screens, the upper electrode having a mesh size within a range of about 30 mesh to 325 mesh and the lower electrode having a mesh size within a range of about 10 mesh to about 80 mesh.
  • the spacing between the electrodes is in a range between about A to about 1/16 inch, such close spacing providing improved image contrast without causing any jamming of the sheet as it passes therethrough.
  • This invention relates generally to electrostatic photocopying apparatus wherein electrically sensitized paper and liquid developer are utilized and, more particularly, to improved apparatus for developing an image bearing sheet as the sheet is conveyed through the developer station thereof.
  • the upper and lower electrodes in a developer station are formed in such a manner that they can be spaced much closer together than in prior art structures using stationary electrodes so that a relatively narrow passageway is available therebetween for the sheet as it is conveyed through the developer station.
  • Such close spacing permits the utilization of lower toner concentrations than are required to obtain the same image contrast in presently known structures.
  • the upper metallic electrode is in the form ofa foraminous metallic material, such as a metallic screen, or other mesh-like structure, while the lower electrode is also in the form of a perforated or meshlike structure, the shape of which is substantially the same as that of the upper electrode.
  • both electrodes are of a mesh-like structure, such as in the form of metallic screens, they can be placed very close to each other without causing a jamming of the sheet during its passage through the developer station. In such structure a marked improvement in contrast in the developed image is achieved.
  • Such a structure eliminates the need for any dielectric guides, or ribs, as are found in the structure of the above referenced prior art MacKenzie patent.
  • FIG. I shows a view in cross-section of the development electrode of the invention.
  • FIG. 2 shows an enlarged view in cross-section of a portion of the structure in FIG. 1, taken along the line 2-2 of FIG. 1.
  • FIG. 1 for the purpose of describing the invention in a preferred embodiment thereof, there is shown a base 10, a tank 11 supported on the base, the tank containing a liquid developer 12 up to the level 13 and having a cover 14 provided with an opening in which a support 15 is mounted by means of brackets 16.
  • a tray 17 In the support 15 is mounted a tray 17 the bottom of which has a plurality of drainage apertures 18.
  • tray 17 can be made of a plastic material or a plastic coated metal, or the like, although it also could be made of metal, if desired.
  • An upper electrode 19 is supported in a frame 20, as by being soldered thereto, which frame is in turn attached to a bracket 21 by end screws 22.
  • the upper electrode 19 is a foraminous metal member, in the form, for example, of a metallic screen.
  • a sheet material S having an electrostatic latent image on its upper surface 23 approaches the tray 17 it is sprayed with a developer through a nozzle 24 which may have a slot or a series of apertures extending across the width of the material, the developer being supplied to the nozzle from tank 11 by a suitable pump through conduit 26 and tube 27.
  • the outlet 28 from the tube to the nozzle which may comprise a slot or series of apertures, is directed toward a wall 29 in the nozzle for the purpose of producing turbulence, thereby causing the stream of developer delivered by the nozzle to be distributed uniformly across the sheet S.
  • the nozzle may be reversed in direction so that the liquid does not strike the paper directly but is generally directed toward the region ofthe upper electrode so as to form the liquid pool through which the sheet passes during its development stage. Developer is pumped into tray 17 faster than it can drain through the bottom apertures thereof so as to maintain the pool in the tray relatively full, the excess flowing over the ends of the tray.
  • the developer in tank 11 is maintained at the level 13 from an inverted bottle 29 having a neck extending through an opening in cover 1d.
  • the bottle is sealed with foil which, when the bottle is inserted, is punctured by a tube 30 appropriately mounted thereon, as described in the aforementioned MacKenzie patent.
  • a second lower electrode 31 is positioned below upper electrode 19 and, particularly with reference to its portion contiguous to upper electrode 19, electrode 31 has substantially the same concave shape and is parallel to the latter electrode.
  • Lower electrode 31 has a large number of perforations and in a preferred embodiment it may be a foraminous, or mesh-like, metal member, such as a metallic screen, and is supported in a frame bracket 32 as by being soldered thereto at its ends, as shown in FIG. 2.
  • Bracket 21 is adjustably affixed to'a frame member 33 via screws 34 and slots 35, frame member 33 being in turn appropriately attached to the support in any suitable manner (not shown).
  • Bracket 32 is fixedly attached to frame member 33 by screws 36 as shown in FIG. 2.
  • Lower tray 17 is attached to the bottom of bracket 32 by screws 37, also as shown in FIG. 2.
  • the developed sheet S passes between squeegee rolls 38-39 which may also serve to draw the material through the tray.
  • squeegee rolls 38-39 which may also serve to draw the material through the tray.
  • a V-shaped guide 40 which guides the material flatwise into the nip between the rolls so that the material does not tend to wrinkle.
  • the spacing between the upper electrode 19 and the lower electrode 31 should be within a range between about inch to about 1/16 inch to achieve the desired improved contrast in the developed image. In one satisfactorily used embodiment of the invention a spacing of about Vs inch has provided excellent results. Even at such closely spaced positions it has been found that there is little or no tendency for the image bearing sheet to jam therebetween during its passage through the developer station.
  • the meshlike character of the lower electrode 31 avoids the need for dielectric ribs or guides and the lower or non-image side 41 of the image bearing sheet effectively contacts the electrode 31 over a relatively large area during its passage without causing any streaking of either the back side or the image side thereof.
  • a metallic screen material is used for upper electrode 19 an effective compromise is made between the relatively coarse mesh size needed to provide sufficient mechanical strength for shaping the electrode to form the desired concave path with minimal support only along its ends through frame 20 and the relatively fine mesh size which is desired in order to achieve the intensified image during the developing process.
  • screens having mesh sizes ranging from about 30 to about 325 have been found effective and in a preferred embodiment an mesh screen size has been found preferable for many practical applications.
  • the mesh size of the lower electrode is not as critical as that of the upper electrode and is selected so that, on the one hand, it is fine enough to produce the desired electrical characteristics and, on the other hand, not so coarse as to cause jamming of the sheet 5 in the openings thereof, particularly as the sheet enters the development structure.
  • the mesh size should be no lower than about 10 mesh, depending on the shape of the development structure, the angle of entry thereto of the sheet S and the nature of the sheet material being used.
  • the use of mesh sizes greater than about 80 mesh may make the fabrication and installation thereof more difficult than necessary in many practical applications, without producing any further improvement in the electrical characteristics that are desired. It has been found that a 30 mesh size has proved to produce satisfactory results for most applications.
  • the spacing between the upper and lower electrodes can lie within a range from about 1/16 inch up to about A inch and it has been found that in one satisfactory embodiment of the invention good contrast can be maintained when such spacing is about /8 inch.
  • the specific structure thereof, as selected for use will normally take into account the relationships between mesh size of the upper electrode, upper and lower electrode spacing, toner concentration, and speed of operation.
  • both the upper and lower electrodes in the embodiment shown and discussed above are metallic, in order to enhance the smoothness of travel of a sheet therethrough, either one or both electrodes in some applications may be very thinly coated with a plastic material, such as an epoxy resin, the thickness of which should be no greater than about 1 mil, so that the desired electrical effect of the electrode on the image will not be disturbed.
  • both the upper and lower electrodes are maintained at the same potential and in the embodiment shown in the drawing they are, in effect, electrically connected together through brackets 21 and 32 which are commonlyattached to frame member 33.
  • Frame member 33 is, in turn, connected to support 15, the latter being at a suitable reference potential, such as ground potential, for example.
  • Apparatus for developing electrostatic images on sheet material comprising a developer station, means for moving said sheet material through said developer station, an upper electrode at said developer station, a lower electrode at said developer station positioned opposite said upper electrode, said sheet material being conveyed between the electrodes, said upper electrode and said lower electrode being of perforated material and being equipotential members, said lower electrode being in contact with said moving sheet material, and the spacing between the electrodes being less than about inch.
  • said upper electrode is made of metallic screen material having a mesh size in the range from about 30 mesh to about 325 mesh.
  • Apparatus in accordance with claim 11 wherein the coating is a dielectric material having a thickness of about 1 mil or less.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Wet Developing In Electrophotography (AREA)
  • Photographic Processing Devices Using Wet Methods (AREA)
  • Management, Administration, Business Operations System, And Electronic Commerce (AREA)
US297779A 1972-10-16 1972-10-16 Development electrode Expired - Lifetime US3871329A (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
US297779A US3871329A (en) 1972-10-16 1972-10-16 Development electrode
AU61237/73A AU6123773A (en) 1972-10-16 1973-10-10 Electrode
DE19732351717 DE2351717A1 (de) 1972-10-16 1973-10-15 Vorrichtung zum entwickeln eines elektrostatischen bildes
FR7336770A FR2203101B1 (enrdf_load_stackoverflow) 1972-10-16 1973-10-15
CA183,355A CA992304A (en) 1972-10-16 1973-10-15 Development electrode
JP48115375A JPS49134338A (enrdf_load_stackoverflow) 1972-10-16 1973-10-16
GB4824673A GB1452520A (en) 1972-10-16 1973-10-16 Electrostatic photocopier apparatus version catalyst

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US297779A US3871329A (en) 1972-10-16 1972-10-16 Development electrode

Publications (1)

Publication Number Publication Date
US3871329A true US3871329A (en) 1975-03-18

Family

ID=23147707

Family Applications (1)

Application Number Title Priority Date Filing Date
US297779A Expired - Lifetime US3871329A (en) 1972-10-16 1972-10-16 Development electrode

Country Status (7)

Country Link
US (1) US3871329A (enrdf_load_stackoverflow)
JP (1) JPS49134338A (enrdf_load_stackoverflow)
AU (1) AU6123773A (enrdf_load_stackoverflow)
CA (1) CA992304A (enrdf_load_stackoverflow)
DE (1) DE2351717A1 (enrdf_load_stackoverflow)
FR (1) FR2203101B1 (enrdf_load_stackoverflow)
GB (1) GB1452520A (enrdf_load_stackoverflow)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4006708A (en) * 1975-05-01 1977-02-08 Eastman Kodak Company Electrographic development apparatus
US5150160A (en) * 1990-04-02 1992-09-22 Fuji Photo Film Co., Ltd. Liquid electrophotographic apparatus having an improved back electrode
US5216201A (en) * 1989-09-05 1993-06-01 Fuji Photo Film Co., Ltd. Liquid electrophotographic developing device
US5319422A (en) * 1989-09-05 1994-06-07 Fuji Photo Film Co., Ltd. Liquid electrophotographic developing device and method thereof

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2645672B2 (de) 1976-10-09 1978-07-27 Hoechst Ag, 6000 Frankfurt Vorrichtung zum Entwickeln von elektrofotografischen Aufzeichnungsmaterialien
DE3062862D1 (en) * 1979-03-30 1983-06-01 Hoechst Ag Device for wetting electrophotographic material
DE3438817A1 (de) * 1984-08-28 1986-03-13 Polychrome GmbH, 3360 Osterode Tonereinheit

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3415223A (en) * 1967-04-24 1968-12-10 Pitney Bowes Inc Development apparatus for electrostatic copiers
US3442254A (en) * 1967-08-28 1969-05-06 Ncr Co Electrostatic developer
US3547076A (en) * 1967-03-23 1970-12-15 Sherwin Williams Co Apparatus for increasing the contrast in liquid immersion developing of electrostatic image
US3577259A (en) * 1968-09-19 1971-05-04 Xerox Corp Liquid development of electrostatic latent images utilizing a tonerfree zone
US3598086A (en) * 1967-10-07 1971-08-10 Minolta Camera Kk Electronic photographic developing device
US3605693A (en) * 1969-09-09 1971-09-20 Pitney Bowes Inc Development electrode
US3682542A (en) * 1970-08-14 1972-08-08 Dennison Mfg Co Development of electrostatic images
US3753393A (en) * 1971-05-21 1973-08-21 Dick Co Ab Liquid developer system for electrostatic copier
US3799791A (en) * 1966-06-30 1974-03-26 Addressograph Multigraph Field control development of electrostatic images

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5124251B1 (enrdf_load_stackoverflow) * 1970-12-28 1976-07-22

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3799791A (en) * 1966-06-30 1974-03-26 Addressograph Multigraph Field control development of electrostatic images
US3547076A (en) * 1967-03-23 1970-12-15 Sherwin Williams Co Apparatus for increasing the contrast in liquid immersion developing of electrostatic image
US3415223A (en) * 1967-04-24 1968-12-10 Pitney Bowes Inc Development apparatus for electrostatic copiers
US3442254A (en) * 1967-08-28 1969-05-06 Ncr Co Electrostatic developer
US3598086A (en) * 1967-10-07 1971-08-10 Minolta Camera Kk Electronic photographic developing device
US3577259A (en) * 1968-09-19 1971-05-04 Xerox Corp Liquid development of electrostatic latent images utilizing a tonerfree zone
US3605693A (en) * 1969-09-09 1971-09-20 Pitney Bowes Inc Development electrode
US3682542A (en) * 1970-08-14 1972-08-08 Dennison Mfg Co Development of electrostatic images
US3753393A (en) * 1971-05-21 1973-08-21 Dick Co Ab Liquid developer system for electrostatic copier

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4006708A (en) * 1975-05-01 1977-02-08 Eastman Kodak Company Electrographic development apparatus
US5216201A (en) * 1989-09-05 1993-06-01 Fuji Photo Film Co., Ltd. Liquid electrophotographic developing device
US5319422A (en) * 1989-09-05 1994-06-07 Fuji Photo Film Co., Ltd. Liquid electrophotographic developing device and method thereof
US5150160A (en) * 1990-04-02 1992-09-22 Fuji Photo Film Co., Ltd. Liquid electrophotographic apparatus having an improved back electrode

Also Published As

Publication number Publication date
FR2203101B1 (enrdf_load_stackoverflow) 1977-03-11
JPS49134338A (enrdf_load_stackoverflow) 1974-12-24
CA992304A (en) 1976-07-06
GB1452520A (en) 1976-10-13
AU6123773A (en) 1975-04-10
FR2203101A1 (enrdf_load_stackoverflow) 1974-05-10
DE2351717A1 (de) 1974-04-18

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