US3636925A - Intensification electrode assembly for developer in office photocopy machine - Google Patents

Intensification electrode assembly for developer in office photocopy machine Download PDF

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Publication number
US3636925A
US3636925A US68355A US3636925DA US3636925A US 3636925 A US3636925 A US 3636925A US 68355 A US68355 A US 68355A US 3636925D A US3636925D A US 3636925DA US 3636925 A US3636925 A US 3636925A
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United States
Prior art keywords
copy sheet
electrode
tray
developer
extending
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Expired - Lifetime
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US68355A
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English (en)
Inventor
Henry G Reuter Jr
Seno Sparer
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American Photocopy Equipment Co
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American Photocopy Equipment Co
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Publication date
Application filed by American Photocopy Equipment Co filed Critical American Photocopy Equipment Co
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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

  • ABSTRACT An electrode assembly for use in an office photocopy machine of the type in which a copy sheet carrying a latent image made up of electrostatic charges is guided into a developer tray having a developer liquid in the form of a colloidal suspension of toner particles in a dielectric vehicle.
  • the electrode has a cylindrical face formed into ridges and appearing, in transverse section, to be of sawtooth configuration.
  • the electrode is submerged in the developer liquid closely adjacent the copy sheet. Means are provided for preventing initial contact between the electrode and the leading edge of the copy sheet.
  • the toner particles tend to follow the electrostatic lines of flux into contact with the surface of the sheet, where deposition occurs in proportion to the amount of charge. While it has been proposed to apply biasing potentials to the intensification electrode, it is generally preferred to have such electrode electrically floating.
  • the sawtooth cross section not only facilitates peripheral circulation but precludes any possibility of a copy sheet becoming hung up" during the course of development.
  • FIG. 1 is a cross-sectional view taken through an electrostatic developer unit employing toner in colloidal suspension
  • FIG. 1a is a diagrammatic and fragmentary section taken along the line 1a1a in FIG. 1;
  • FIG. 2 is an enlarged fragmentary section taken along the line 22 in FIG. 1;
  • FIG. 3 is an enlarged fragmentary section showing the sawtooth configuration of the intensification electrode
  • FIG. 4 is a diagram at an enlarged scale taken along line 4- 4 in FIG. 3 showing the orientation of the lines ofelectrostatic flux which determines the path followed by the toner particles;
  • FIG. 5 is an enlarged fragment based upon FIG, 1 and showing control of the leading edge of the copy sheet at the entryway.
  • FIG. I in vertical section, a typical developer unit 10 having a base 11 and superimposed tray 12 which fit together and both of which may be molded of plastic.
  • the tray is of generally cylindrical contour, having guides in the form of a plurality of axially spaced ribs 13 which are smoothly surfaced and molded integrally and which together define a cylindrical guide surface 14 (see FIG. 4) having an entryway 15 at one end and an exit 16 at the other.
  • the tray has a charge 20 of developer liquid which, during operation of the machine, is pumped from a lower compartment indicated at 21 via a line 22 for discharge at an orifice 23. Drain openings, not shown, at the ends of the tray permit the excess developer liquid to drain back down into the storage space 21.
  • the tray may simply be assumed to have a charge of developer liquid maintained at approximately the indicated level.
  • a pair of inlet rollers 31 are provided driven by a motor M and horizontally arranged so that the outlet nip feeds the copy sheet 30 downwardly into engagement with the guide surface 14 within the tray.
  • the copy sheet because of its normal and inherent stiffness, tends to follow a path of maximum diameter so that it maintains contact with the guide surface 14 until the exit 16 is reached.
  • the copy sheet is engaged by a pair of rotating expeller rollers 32 driven at substantially the same peripheral speed by the motor M and at least one of which is resiliently surfaced so as to squeegee the excess developer liquid into the apron portion 33 of the tray. From the expeller rollers the copy sheet, in practically dry condition, is subjected to a flow of warmed air and discharged into suitable collector tray.
  • a metallic intensification electrode is provided submerged in the developer liquid and having a generally cylindrical surface which extends parallel to the copy sheet guide surface 14, the electrode surface being formed with longitudinally extending ridges closely coupled to the copy sheet and having a sawtooth profile defining open-ended grooves which serve as reservoirs of developer liquid immediately adjacent the closely coupled regions for complete and prompt development of the charged areas. Further in accordance with the invention the sloping sides of the ridges are faced toward the entryway to facilitate flow of the developer liquid from the grooves upon passage of the copy sheet and to insure free movement of the copy sheet through the developer unit without any possibility that the leading edge of the copy sheet may be obstructed by, or become hung up upon, one of the ridges.
  • the metallic intensification electrode generally indicated at 40, has a cylindrical portion 41 and a flat horizontal portion 42 and may be conveniently formed as a D-shaped extrusion of aluminum or the like.
  • each ridge has a crown 44, a sloping surface 45 which extends in the direction of the entryway, and an abrupt, inwardly extending surface 46.
  • the surfaces of adjacent ridges define grooves 47 which are occupied by developer liquid and which serve as local reservoirs for furnishing developer liquid to the restricted or close-coupled regions 48 at the crowns of each of the ridges.
  • the spacing in the regions ofclosest approach, indicated at 48, is preferably on the order of 0.050 inch. Assuming that a typical copy sheet having a thickness of 0.004 inch is used, this leaves a net spacing between the crowns of the ridges and the surface of the copy sheet on the order of0.046 inch.
  • FIG. 4 shows, in greatly enlarged form, a small section of copy sheet 30 having a sensitive layer 30a, formed of particles of zinc oxide in a dielectric binder, with a paper backing indicated at 30b.
  • the copy sheet will have a latent image in the form of negatively charged areas such as that indicated at 50.
  • the negatively charged region of the copy sheet will tend to induce a positive charge 51 in the portion of the intensification electrode which is directly op posite.
  • lines of electrostatic flux indicated at 52 which extend generally perpendicularly to the face of the copy sheet and which represent a force field capable of acting upon positively charged toner particles, such as indicated at 53, which are colloidally suspended in the liquid vehicle.
  • the vehicle may consist of petroleum distillate, Freon, or other thin dielectric liquid capable of reasonably rapid evaporation as the copy sheet leaves the developer unit.
  • the positively charged toner particles are attracted to the surface 300 along the lines of flux to pigment the charged areas and tending to neutralize the charge. Most of the development occurs in the region of the first few ridges. Passage of the sheet opposite the additional ridges provides additional opportunity for deposition of the toner so that the black areas are quickly and completely saturated.
  • the sawtooth configuration facilitates the drawing of fresh developer liquid into the close-coupled regions by reason of movement of the copy sheet.
  • movement of the sheet 30 tends to draw fresh liquid from the grooves 47 which act as local reservoirs for toner.
  • the sloping surfaces 45 on each of the ridges will tend to shed the leading edge thereby preventing any possibility of hang-up" and resultantjamming in the developer unit.
  • an insulated guide is provided at the entryway of the tray extending along the length of the electrode and in a slightly overhanging position so that the leading edge of the sheet is guided into engagement with the tray guide surface, preventing direct contact between the face of the sheet and the initial ridge or ridges of the intensification electrode.
  • the developer assembly is provided with a top member 60, which may be molded of plastic or other insulating material, and which has a surface 61 at the leading edge which slightly overhangs the first of the ridges 43 of the electrode. in the event that the sheet 3!) does not proceed straight downwardly from the inlet rollers 31 but tends to feed in an angled position as shown in FIG.
  • the electrode may be added to older designs of developer trays thereby achieving the results of the invention, including an increase in reliability and the crispness and density of the resulting copies, at minimum cost.
  • a developer assembly for an electrostatic type office photocopy machine comprising a tray hav ing an entryway and an exit with internal guides extending therebetween for guiding a charged copy sheet face up about a generally cylindrical path, the tray having a charge of toner particles colloidally suspended in a thin insulating vehicle, a metallic intensifier electrode having a cylindrical surface extending in parallel relationship to the copy sheet guide means, the surface of the electrode being formed with longitudinally extending ridges having crowns extending into close-coupled relation to the copy sheet and defining between them openended grooves which serve as reservoirs of developer liquid immediately adjacent the closely coupled regions for continuous replenishment of the toner particles therein, the ridges in cross section having a sawtooth profile with the sloping sides of the ridges being faced toward the entryway.
  • the intensification electrode is a hollow extrusion formed of aluminum or the like having a generally D-shaped cross section.
  • a developer assembly for an electrostatic-type of office photocopy machine comprising a tray having a generally cylindrical inner surface with an entryway along one side and an exit along the other, a pair of entry rollers at the entryway having a nip aligned therewith to direct the leading edge of the copy sheet against the cylindrical inner surface, the tray having a charge of toner particles colloidally suspended in a thin insulating vehicle, a metallic intensifier electrode having a cylindrical outer surface evenly spaced with respect to the inner surface of the tray, an insulator extending along the length of the intensification electrode at the entryway and slightly overhanging the same for intercepting the leading edge of the copy sheet and for deflecting it toward the inner surface of the tray thereby to prevent the leading edge portion of the copy sheet from directly engaging the adjacent portion of the metallic electrode, the surface of the electrode being formed with ridges along the length thereof and extending beyond the lateral edges of the copy sheet, said ridges in cross section being of sawtooth configuration having a crown extending into close-coupled relation

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Wet Developing In Electrophotography (AREA)
US68355A 1970-08-31 1970-08-31 Intensification electrode assembly for developer in office photocopy machine Expired - Lifetime US3636925A (en)

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US6835570A 1970-08-31 1970-08-31

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US (1) US3636925A (enrdf_load_stackoverflow)
JP (1) JPS5125144B1 (enrdf_load_stackoverflow)
CA (1) CA941151A (enrdf_load_stackoverflow)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3784397A (en) * 1970-02-04 1974-01-08 Xerox Corp Imaging system
US3791345A (en) * 1972-05-09 1974-02-12 Itek Corp Liquid toner applicator
US4527509A (en) * 1984-05-10 1985-07-09 Gaf Corporation Dielectric film processor
EP0191733A1 (de) * 1985-02-12 1986-08-20 Ilford Ag Vorrichtung zur Flüssigkeitsbehandlung von lichtempfindlichem blattförmigem Material
US5032871A (en) * 1989-02-27 1991-07-16 Fuji Photo Film Co., Ltd. Guide with oblique ribs for wiping a material
US5302996A (en) * 1992-11-25 1994-04-12 Eastman Kodak Company Apparatus for processing photosensitive material
WO1996006381A1 (en) * 1994-08-18 1996-02-29 Picture Productions Limited Partnership Method and apparatus for processing photosensitive sheet material

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63310588A (ja) * 1987-06-11 1988-12-19 Tonichi Denki Kk 電子レンジ等のヒ−タ盤およびその製造方法

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3249088A (en) * 1963-04-03 1966-05-03 Scm Corp Developing tank unit for electrostatic printing
US3369918A (en) * 1964-10-28 1968-02-20 Xerox Corp Development of latent electrostatic images with crested waves of liquid developer
US3388688A (en) * 1966-06-30 1968-06-18 Harris Intertype Corp Electrophotographic apparatus
US3406655A (en) * 1965-04-23 1968-10-22 Lumoprint Zindler Kg Apparatus for producing copies
US3547076A (en) * 1967-03-23 1970-12-15 Sherwin Williams Co Apparatus for increasing the contrast in liquid immersion developing of electrostatic image

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3359945A (en) * 1966-10-17 1967-12-26 Dennison Mfg Co Development of electrostatic images
JPS458512Y1 (enrdf_load_stackoverflow) * 1967-08-31 1970-04-22

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3249088A (en) * 1963-04-03 1966-05-03 Scm Corp Developing tank unit for electrostatic printing
US3369918A (en) * 1964-10-28 1968-02-20 Xerox Corp Development of latent electrostatic images with crested waves of liquid developer
US3406655A (en) * 1965-04-23 1968-10-22 Lumoprint Zindler Kg Apparatus for producing copies
US3388688A (en) * 1966-06-30 1968-06-18 Harris Intertype Corp Electrophotographic apparatus
US3547076A (en) * 1967-03-23 1970-12-15 Sherwin Williams Co Apparatus for increasing the contrast in liquid immersion developing of electrostatic image

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3784397A (en) * 1970-02-04 1974-01-08 Xerox Corp Imaging system
US3791345A (en) * 1972-05-09 1974-02-12 Itek Corp Liquid toner applicator
US4527509A (en) * 1984-05-10 1985-07-09 Gaf Corporation Dielectric film processor
EP0191733A1 (de) * 1985-02-12 1986-08-20 Ilford Ag Vorrichtung zur Flüssigkeitsbehandlung von lichtempfindlichem blattförmigem Material
US4647173A (en) * 1985-02-12 1987-03-03 Ciba-Geigy Ag Apparatus for the liquid-processing of light-sensitive sheet material
US5032871A (en) * 1989-02-27 1991-07-16 Fuji Photo Film Co., Ltd. Guide with oblique ribs for wiping a material
US5302996A (en) * 1992-11-25 1994-04-12 Eastman Kodak Company Apparatus for processing photosensitive material
WO1996006381A1 (en) * 1994-08-18 1996-02-29 Picture Productions Limited Partnership Method and apparatus for processing photosensitive sheet material
US5502535A (en) * 1994-08-18 1996-03-26 Picture Productions Method and apparatus for processing photosensitive sheet material

Also Published As

Publication number Publication date
CA941151A (en) 1974-02-05
DE2143039A1 (de) 1972-03-02
DE2143039B2 (de) 1977-02-17
JPS5125144B1 (enrdf_load_stackoverflow) 1976-07-29

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