US3916827A - Perforate development electrode - Google Patents

Perforate development electrode Download PDF

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Publication number
US3916827A
US3916827A US338905A US33890573A US3916827A US 3916827 A US3916827 A US 3916827A US 338905 A US338905 A US 338905A US 33890573 A US33890573 A US 33890573A US 3916827 A US3916827 A US 3916827A
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United States
Prior art keywords
electrode
pressure reducing
image side
sheet
liquid toner
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
US338905A
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English (en)
Inventor
Clyde P Grant
Merton A Look
Richard M Lowe
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.)
Warren SD Co
Original Assignee
Scott Paper 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 Scott Paper Co filed Critical Scott Paper Co
Priority to US338905A priority Critical patent/US3916827A/en
Priority to CA179,973A priority patent/CA990590A/en
Priority to GB4115673A priority patent/GB1428144A/en
Priority to NL7312412A priority patent/NL7312412A/xx
Priority to DE19732347880 priority patent/DE2347880A1/de
Priority to IT52949/73A priority patent/IT996269B/it
Priority to FR7335752A priority patent/FR2220813B1/fr
Priority to BE1005408A priority patent/BE805761A/xx
Priority to JP48113783A priority patent/JPS49122343A/ja
Application granted granted Critical
Publication of US3916827A publication Critical patent/US3916827A/en
Priority to US06/066,395 priority patent/US4342823A/en
Priority to US06/275,615 priority patent/US4384035A/en
Assigned to S.D. WARREN COMPANY reassignment S.D. WARREN COMPANY ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: SCOTT PAPER COMPANY
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
    • G03G15/101—Apparatus for electrographic processes using a charge pattern for developing using a liquid developer for wetting the recording material

Definitions

  • ABSTRACT Apparatus for developing electrostatic images on electrophotographic material by means of a perforate development electrode and liquid toner, without immersing the material in a bath of toner.
  • liquid developers used in electrophotography comprise a dispersion of solid toner particles in a liquid having dielectric properties.
  • the toner particles which bear a charge, are attracted to the electrophotographic material in accordance with the charge of the image upon it, whereas the dielectric liquid flows off. The result is a visible image.
  • the electrophotographic material is brought into contact with the liquid developer by drawing it through a container which contains the liquid devleoper (a bath), or a thin film of liquid developer is applied to the surface of the material by spraying or by transfer roll.
  • a container which contains the liquid devleoper (a bath)
  • a thin film of liquid developer is applied to the surface of the material by spraying or by transfer roll.
  • the bath type of developer suffers from several disadvantages, particularly when the imaged material is paper.
  • the sheet When the sheet is immersed in the toner bath, it absorbs or picks up a considerable amount of carrier liquid for the toner particles and carries the liquid with it from the bath. This amount of liquid must then be evaporated from the sheet. This evaporation requires energy and time for drying the sheet, and replenishment of the bath.
  • maintenance of the virtual contact between the paper and the stationary electrode while guiding the paper through the are which it must transverse through the bath is very difficult to achieve. As a practical matter, the result is often actual contact.
  • a perforate development electrode is placed across the width (the dimension perpendicular to the direction of travel) of the imaged material. Liquid toner is delivered uniformly through the development electrode. After the toner flows over the imaged material, it is collected and recirculated.
  • This invention is directed to apparatus for developing images on material provided with an electrophotographic surface, irrespective of the substrate.
  • copy paper and substrates adopted for use as lithographic printing plates are contemplated.
  • FIGS. 1 and 2 are side-elevational views of alternative forms of developing apparatus according to the invention.
  • FIGS. 3 and 4 are fragmentary sectional views of other forms of developing apparatus according to the invention.
  • the apparatus shown in FIG. 1 includes electrophotographic material 10, which has a latent charge image on its upper surface and is fed beneath the perforate development electrode 11. While passing beneath the electrode, the material is brought into contact with liquid toner flowing through the electrode.
  • the toner is supplied through spray means in the form of a perforated tube 12 which directs the liquid against a baffle 13, adjacent the electrode 11, which reduces and makes uniform the pressure, thus providing uniform flow of the liquid over and through the electrode.
  • the spray tube 12 is provided with either a row of holes or a slit along its length to allow the toner to either spray or squirt against the pressure reducing plate 13.
  • Both the tube 12 and the plate 13 are preferably of the same length as the electrode 11 and may be fabricated from any suitable material. Toner accumulates in the space formed between the plate 13 and the electrode 11 and flows uniformly through the perforate electrode 11 onto the image side of the sheet without contacting the side opposite the image side.
  • the development electrode must of course be formed of electrically conductive material, but must also be sufficiently porous to be readily permeable to the toner particles and the carrier fluid.
  • a screen comprised of a network of relatively fine metal wires with sufficiently large spaces therebetween to provide a high degree of permeability to the toner bath may be employed.
  • a metal plate perforated with holes of uniform size and distribution can also be utilized.
  • the diameter of the holes in the electrode should be the same order of magnitude as the distance between the electrode and the sheet. By way of example, if such distance is 0.030 inch, the holes would be smaller than 0.10 inch and preferably in this case, smaller than 0.030. Especially preferred for use at said distance is a brass plate having holes 0.016 inch in diameter and having 1479 such holes per square inch or about 30% open area.
  • the length (i.e., the dimension in the direction of travel of the sheet), of the development electrode is from 0.75 to 6 inches. This dimension is dependent on a variety of variables. These include the composition of the toner, its concentration, the nature of the electrophotographic material, the rate of travel of the sheet past the electrode, and the distance between the sheet and the electrode in general, the closer the electrode is to the sheet, the shorter the electrode may be. As will be appreciated by those skilled in the art, the closeness of the electrode to the sheet is limited by practical considerations such as maintenance of a gap to prevent scratches and the problem that if the electrode is too close the rate of depletion of the toner will exceed the rate at which it can be supplied through the available space.
  • the general considerations which apply to the length of the electrode are that as length is increased, it becomes more difficult to maintain a uniform distance between the electrode and the sheet and that as the length is decreased, other things being equal, the rate of travel of the imaged material must be reduced.
  • FIG. 2 A modification of the embodiment shown in FIG. 1 is presented in FIG. 2, in which the baffle 13 has been omitted.
  • the spray means 12 directs liquid toner against the adjacent guide roll 24. Toner accumulates in the nip formed between the roll 14 and the sheet 10 to a height appropriate to cover the electrode 11 and flows through it onto the image side of the sheet without contacting the side opposite the image side.
  • the electrode may be the floating variety on which a complementary potential is developed by virtue of its proximity to the changed surface of the electrophotographic material, or may be used as a biased electrode on which a fixed potential is impressed from a separate source. In either case, the electrode must be electrically isolated from other portions of the machine in which it is employed. A still further alternative is that the electrode be grounded. The accomplishment of these electrical arrangements is well within the skill of the person of ordinary skill in the art to which this invention pertains. An illustrative means of mounting the electrode is depicted in FIGS. 1 and 2 in which the electrode 11 is suspended from the post and bracket assembly 15.
  • the toner liquid flows off the edges of the imaged material into a tray, not shown, and thence to a tank from which it is recirculated by a pump to the spray tube 12.
  • the flat baffle 13 of FIG. 1 is replaced by channel shaped baffle 33 disposed between the tube 12 and the electrode 11.
  • the channel is filled to overflowing by the spray tube 12 and the toner liquid flows downward and outward uniformly across the development electrode 11 and through the holes therein onto the image side of the sheet without contacting the side opposite the image side.
  • the baffle 33, the electrode 11 and the sheet 10 are disposed in the horizontal plane.
  • the channel shaped baffle 33 of FIG. 3 is replaced by a block 43 of reticulated polyurethane foam, described in US. Pat. No. 3,171,820 (Volz).
  • the foam breaks up the flow of the liquid, causing it to be well distributed before it reaches the surface of the imaged material.
  • the pore size of the foam should be as fine as possible consistent with the requirement that the pores be sufficiently large to permit the ready passage of the toner particles. Obviously, the choice of pore size will depend upon the maximum size of the particles in the toner desired to be used.
  • the apparatus of the present invention provides several advantages over the bath or immersion type of development electrodes of the prior art.
  • the latter generally requires a curved path of movement of the electrophotographic material, which renders difficult the control of the spacing between the material and the electrode.
  • the prior art discloses stationary electrodes disposed in a bath in virtual contact with sheets sliding past the electrode. Practically, unless the separation is fairly large, actual contact occurs, with smears and streaks resulting.
  • the planar or flat electrode arrangement provided by the present invention permits a planar alignment of the material, by which the proximate relationship between the material and the electrode is more easily maintained.
  • toner is applied to only one side of the sheet, less toner-carrying fluid is carried away from the development station on the sheet than is the case in bath arrangements, and therefore, there is less need to replenish the toner. Furthermore, since there is less toner-carrying fluid on the sheet, the requirements for drying are less.
  • toner is delivered to the vicinity of the electrode by a tube which squirts toner against pressure reducing means disposed close to the electrode and which reduces and makes uniform the pressure, thus providing uniform flow of the liquid over and through the electrode.
  • pressure reducing means disposed close to the electrode and which reduces and makes uniform the pressure, thus providing uniform flow of the liquid over and through the electrode.
  • Other arrangements or constructions for delivering liquid toner uniformly through the development electrode are deemed to be within the skill of those of ordinary skill in the art to which the present invention pertains. Accordingly, it should be understood that the forms of the present invention described above and shown in the accompany- I ing drawing are illustrative only and not intended to 5 6 b. spray means for directing liquid toner against the 3.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Wet Developing In Electrophotography (AREA)
US338905A 1973-03-07 1973-03-07 Perforate development electrode Expired - Lifetime US3916827A (en)

Priority Applications (11)

Application Number Priority Date Filing Date Title
US338905A US3916827A (en) 1973-03-07 1973-03-07 Perforate development electrode
CA179,973A CA990590A (en) 1973-03-07 1973-08-30 Method and apparatus for developing electrostatic images on a sheet of electrophotographic copy material
GB4115673A GB1428144A (en) 1973-03-07 1973-08-31 Method and apparatus for developing electrostatic images on a sheet of electrophotographic copy material
NL7312412A NL7312412A (cg-RX-API-DMAC7.html) 1973-03-07 1973-09-07
DE19732347880 DE2347880A1 (de) 1973-03-07 1973-09-20 Verfahren und einrichtung zum entwickeln elektrostatischer abbildungen auf einem blatt elektrophotographischen kopiermaterials
FR7335752A FR2220813B1 (cg-RX-API-DMAC7.html) 1973-03-07 1973-10-05
IT52949/73A IT996269B (it) 1973-03-07 1973-10-05 Metodo ed apparecchio per lo svilup po di immagini elettroafiche statiche su un foglio di materiale per copie elettrofotog
BE1005408A BE805761A (fr) 1973-03-07 1973-10-08 Procede et appareil de developpement d'images electrostatiques sur une feuille de materiau de reproduction electrophotgraphique
JP48113783A JPS49122343A (cg-RX-API-DMAC7.html) 1973-03-07 1973-10-09
US06/066,395 US4342823A (en) 1973-03-07 1979-08-14 Perforate development electrode
US06/275,615 US4384035A (en) 1973-03-07 1981-06-22 Perforate development electrode

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US338905A US3916827A (en) 1973-03-07 1973-03-07 Perforate development electrode

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US05570865 Division 1975-04-23

Publications (1)

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US3916827A true US3916827A (en) 1975-11-04

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US338905A Expired - Lifetime US3916827A (en) 1973-03-07 1973-03-07 Perforate development electrode

Country Status (8)

Country Link
US (1) US3916827A (cg-RX-API-DMAC7.html)
JP (1) JPS49122343A (cg-RX-API-DMAC7.html)
BE (1) BE805761A (cg-RX-API-DMAC7.html)
CA (1) CA990590A (cg-RX-API-DMAC7.html)
DE (1) DE2347880A1 (cg-RX-API-DMAC7.html)
FR (1) FR2220813B1 (cg-RX-API-DMAC7.html)
GB (1) GB1428144A (cg-RX-API-DMAC7.html)
IT (1) IT996269B (cg-RX-API-DMAC7.html)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4294192A (en) * 1979-05-30 1981-10-13 Sharp Kabushiki Kaisha Liquid electrostatic image developing system employs mesh development electrode
DE4118434A1 (de) * 1990-06-06 1991-12-12 Mitsubishi Paper Mills Ltd Verfahren zur elektrophotographischen umkehr-nassentwicklung
US20070256460A1 (en) * 2006-05-03 2007-11-08 Fleissner Gmbh Apparatus for applying dye to a textile

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5852216B2 (ja) * 1980-01-30 1983-11-21 イ−・アイ・デュポン・ド・ネモア−ス・アンド・コンパニ− フイルム処理装置

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3096198A (en) * 1958-12-22 1963-07-02 Ibm Method for developing latent field images with liquid inks
US3133484A (en) * 1961-09-29 1964-05-19 Rca Corp Electrostatic printing apparatus
US3411482A (en) * 1967-01-30 1968-11-19 Varian Associates Electrographic toner development employing a clean-up electrode structure for removing unwanted background
US3618567A (en) * 1969-09-15 1971-11-09 Varian Associates Apparatus for developing latent electrographic images with liquid ink
US3643628A (en) * 1967-12-20 1972-02-22 Meyer L Sugarman Compact liquid toner apparatus with straight-through feed
US3667987A (en) * 1969-12-12 1972-06-06 Scm Corp Method of developing latent electrostatic images
US3669073A (en) * 1969-04-04 1972-06-13 American Photocopy Equip Co Electrostatic developing system
US3749059A (en) * 1969-08-27 1973-07-31 Fuji Photo Film Co Ltd Apparatus for developing electrostatic latent image
US3752119A (en) * 1970-06-11 1973-08-14 Canon Kk Liquid toner applicator
US3776630A (en) * 1971-03-29 1973-12-04 Ohno Res & Dev Lab Electrostatic printing method and apparatus
US3799791A (en) * 1966-06-30 1974-03-26 Addressograph Multigraph Field control development of electrostatic images

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3096198A (en) * 1958-12-22 1963-07-02 Ibm Method for developing latent field images with liquid inks
US3133484A (en) * 1961-09-29 1964-05-19 Rca Corp Electrostatic printing apparatus
US3799791A (en) * 1966-06-30 1974-03-26 Addressograph Multigraph Field control development of electrostatic images
US3411482A (en) * 1967-01-30 1968-11-19 Varian Associates Electrographic toner development employing a clean-up electrode structure for removing unwanted background
US3643628A (en) * 1967-12-20 1972-02-22 Meyer L Sugarman Compact liquid toner apparatus with straight-through feed
US3669073A (en) * 1969-04-04 1972-06-13 American Photocopy Equip Co Electrostatic developing system
US3749059A (en) * 1969-08-27 1973-07-31 Fuji Photo Film Co Ltd Apparatus for developing electrostatic latent image
US3618567A (en) * 1969-09-15 1971-11-09 Varian Associates Apparatus for developing latent electrographic images with liquid ink
US3667987A (en) * 1969-12-12 1972-06-06 Scm Corp Method of developing latent electrostatic images
US3752119A (en) * 1970-06-11 1973-08-14 Canon Kk Liquid toner applicator
US3776630A (en) * 1971-03-29 1973-12-04 Ohno Res & Dev Lab Electrostatic printing method and apparatus

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4294192A (en) * 1979-05-30 1981-10-13 Sharp Kabushiki Kaisha Liquid electrostatic image developing system employs mesh development electrode
DE4118434A1 (de) * 1990-06-06 1991-12-12 Mitsubishi Paper Mills Ltd Verfahren zur elektrophotographischen umkehr-nassentwicklung
US5398105A (en) * 1990-06-06 1995-03-14 Mitsubishi Paper Mills Limited Method of electrophotographic wet reversal development
US20070256460A1 (en) * 2006-05-03 2007-11-08 Fleissner Gmbh Apparatus for applying dye to a textile

Also Published As

Publication number Publication date
IT996269B (it) 1975-12-10
BE805761A (fr) 1974-04-08
CA990590A (en) 1976-06-08
DE2347880A1 (de) 1974-09-12
FR2220813A1 (cg-RX-API-DMAC7.html) 1974-10-04
GB1428144A (en) 1976-03-17
JPS49122343A (cg-RX-API-DMAC7.html) 1974-11-22
FR2220813B1 (cg-RX-API-DMAC7.html) 1978-02-10

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Free format text: PATENTED FILE - (OLD CASE ADDED FOR FILE TRACKING PURPOSES)

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Owner name: S.D. WARREN COMPANY

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:SCOTT PAPER COMPANY;REEL/FRAME:004811/0245

Effective date: 19871013