US3836361A - Method of developing an electrophotographic image with a bias field - Google Patents

Method of developing an electrophotographic image with a bias field Download PDF

Info

Publication number
US3836361A
US3836361A US00294000A US29400072A US3836361A US 3836361 A US3836361 A US 3836361A US 00294000 A US00294000 A US 00294000A US 29400072 A US29400072 A US 29400072A US 3836361 A US3836361 A US 3836361A
Authority
US
United States
Prior art keywords
developer
biasing
image
insulating
resin
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
US00294000A
Other languages
English (en)
Inventor
K Metcalfe
A Clements
C Wilson
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.)
COMMONWEALTH OF AU CARE OF SECRETARY AU
COMMW OF AU CARE OF SECRET
Original Assignee
COMMW OF AU CARE OF SECRET
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 COMMW OF AU CARE OF SECRET filed Critical COMMW OF AU CARE OF SECRET
Application granted granted Critical
Publication of US3836361A publication Critical patent/US3836361A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/12—Developers with toner particles in liquid developer mixtures
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G13/00—Electrographic processes using a charge pattern
    • G03G13/06—Developing
    • G03G13/10—Developing using a liquid developer, e.g. liquid suspension

Definitions

  • ABSTRACT A method of developing electrostatic images comprising subjecting a surface containing an electrical image to a liquid developer having two dissimilar components, one of which is a first developer component having a polarity such that it develops the image by attracting the first developer component to the image. A bias field is maintained through the liquid such that as the image is developed by the first developer component the second developer component is moved away from the surface being developed. When the first developer has been differentially developed on the surface the polarity of the bias field is reversed to cause the second developer component to be deposited on the first developer component.
  • the development of electrophotographic images usually comprises the charging of a surface which consists of a photoconductive medium such as zinc oxide set in an insulating resin, or selenium or any of the sulphur compounds used as a thin layer, and then exposing the layer to light after charging to bleed away the charges in those areas where the image is light struck, after which the surface, now containing a latent electrostatic image in the dark areas is subjected to a developer which is selective to the charged surface and deposits thereon.
  • a photoconductive medium such as zinc oxide set in an insulating resin, or selenium or any of the sulphur compounds used as a thin layer
  • Developing of the image can be by means of dry developer powders, either used as a powder cloud or carried over the surface by means of granules which give to the developer powders a triboelectric charge, or the developer can be a liquid developer in which the marking particles are suspended to be freely mobile in a carrier liquid having a resistivity sufficiently high to prevent destruction of the latent electrostatic image during development, such as for instance as cm. and a dielectric constant less than 3, the liquid development process being generally improved by use of a control medium which regulates the movement of the toner particles to ensure that correct deposition takes place.
  • the present invention applies to either type of process, namely that known as chargeless development or that using a precharging of the surface but by use of the present process much more effective development of chargeless images is possible due to the denser images which can be obtained and also due to the much better control which the present invention can apply generally. In the case of charged surfaces this is still however true and the invention will be seen to have substantial merit with this type of process also.
  • the present invention is directed to development of a surface which has on it an image produced either by precharging and modifying by electromagnetic waves or by simply modifying by electromagnetic waves, and then developing by application of a liquid developer in which marking particles are suspended in the carrier liquid of such a developer, the invention utilizing a primary developer component and a secondary developer component with two stage biasing during development to deposit the two components sequentially the first biasing being carried out with a polarity such that the secondary component which comprises toner particles are moved away from the surface to be developed while the primary developer component develops the image, after which the polarity is reversed and the toner particles are driven down on to the primary developer component.
  • the photoconductor surface is such that where activated by electromagnetic waves, the photoconductive surface is in a conductive state but where not so activated in an insulating state,
  • the developer is selected to contain two components, one being more insulating than the other, the more insulating component being inherently attracted to the insulated field bearing area of the photoconductor because of a selected opposite charge potential, the other relatively more conductive component being such that it is not retained on either a remote electrode unless it is insulated or on the conductive part of the photoconductor surface because of charge exchange (it being capable of having either a positive or negative characteristic according to this) so that development is effected by first lightly developing the image by the first insulating component while the bias removes the other more conductive component from the photoconductive area, and then intensifying the development by re versing the electrode polarity which will allow the sec ond developer to be built up on the first developed area only because this is the only area where charge exchange does not take place within the time available.
  • the invention produces highly satisfactory images and allows required contrast and densities to be obtained not only by a selection of ap limbate developers but by the time element applicable to the movement of the developer during the initial denuding of the face of the photoconductive medium of developer during the initial application of a field and the subsequent reversing of the field to drive down the developer in the required areas.
  • the invention also has various other advantages which are considered to be important, these being for instance the improvements to fixing which can result by the deposition of a tacky first developer component and also the greater flexibility of development.
  • the insulating medium can be chosen to develop the latent image on the surface, it having been found that in the case of a photoconduc tive surface, the insulating medium, be it a resin developer component or a liquid component, will be forced down on to the surface if correctly selected and will deposit irrespective of whether the latent image has been formed by precharging and light bleeding or the like or whether the surface has merely been dielectrically modified by simply exposing the surface to electromagnetic radiation of patterned form, or is otherwise dielectrically charged.
  • the insulating medium be it a resin developer component or a liquid component
  • an insulator has charge carriers not readily available, we have demonstrated that an insulator medium will retain for a longer time whatever charge it has, and therefore because of the lack of readily available charge carriers, when such a surface is deposited on to a surface which is subsequently changed in polarity, it is difficult to drive off these particles because of the difficulty of exchanging charges with the surface on which the particles are deposited.
  • FIG. 1 is a schematic view showing how when a photoconductor membrane 1 is placed into a developer 2 the primary developer which is the insulator medium 3 is drawn to the image area 4 but when the base electrode 5 and distant electrode 6 are energised negatively and positively respectively, the toner particles 7 which form the secondary developer and which have an inherent negative charge are moved toward the remote electrode 6 to denude the area near the negative base electrode 5.
  • the distant electrode bias insulator coating 8 on it to discourouge charge exchange.
  • FIG. 2 shows how, when the polarity of the electrodes is reversed, the toner particles 7 are drawn down toward the base electrode 5 but can be retained only where they deposit on the insulator image 3, because if they contact the surface of the conductive part of the photoconductive surface they exchange charges under influence of the base electrode 5 and move away as shown in that figure.
  • the invention offers very much more effective control than has been possible heretofore in that a simple developer can be used which consists of insulating particles or an insulating liquid together with relatively conducting developer particles suspended in an insulating liquid, and by so selecting the liquid that the required insulating value is present, this liquid or the insulator medium is first deposited in an imagewise manner and having been deposited is somewhat difficult to remove from the area where it has been deposited, so that when the developer particles can be discharged from the electrode by reversal of the field, are directed towards the image area and can be forced down at the required localities before such time as the insulating medium can be released from its deposited position by such insulating medium taking the charge of the area with which it is in contact.
  • the slower acting insulating medium is first deposited, and once deposited, development can take place without removing the insulating medium, as the toner particles are more readily moved in the field because of greater conductivity and would on contact with a conducting surface on which they are deposted immediately change their characteristic by charge transfer and would again move away from the deposited site.
  • the insulating medium is a resin supported in the carrier liquid, it can be in a partly disolved or a disolved state to act as an adhesive to lock toner particles to the image area when deposited thereon, the fixing becoming effective when the carrier liquid evaporates.
  • Binder Lustrasol AUISO/SO, Trade Mark Alkyd modified acrylic resin, supplied by Reichold Chemicals of Aust. Ltd.
  • a typical first developer component formed as follows:
  • a relatively insulating developer concentrate of relatively coarse particle size suitable for dispersion in paraffinic liquids (carrier liquids) such as cyclohexane or Isopar G or Isopar E may be comprised as follows:
  • copolymeric resins are relatively positive and tend automatically to deposit on a negative latent image so soon as development takes place.
  • a second component developer that is a conductive developer with negative characteristic is formed as follows.
  • EXAMPLE 2 In example 1 replace the carbon black by Irgafin S1 trade mark phthalocyanine blue pigment, coated by a copolymeric resin as manufactured by Geigy, Australasia Pty. Ltd.
  • EXAMPLE 3 In example 1 replace the Pliolite VT by a styrene/acrylate copolymer such as that marketed under the trade mark Pliolite ACL trade mark of Australian Synthetic Rubber, of Altona, Victoria, Australia.
  • Superbeckosol 1352/60 a semi-drying safflower oil isophthalic-modified long oil alkyd resin with 59-61 percent non-volatile matter, acid value 3-6, oil length 60 percent, viscosity Gardner Holdt Y-Z.
  • VINYLITE VYNW a vinyl chloride-acetate resin, approximate composition vinyl chloride 97 percent, vinyl acetate 3 percent, and specific gravity 1.39.
  • PENTACITE P423 is a modified pentarethyritol ester resin with acid number 20-30.
  • PLIOLITE VT RESIN is a styrene/butadiene type copolymer rubber made by the Goodyear Corp., U.S.A. and prepared by the G.R.S. method in which the butadiene polymerises in the main by a 1,4-addition.
  • Pliolite VT is a vinyl toluene/butadiene random copolymer rubber, soluble in mineral spirits.
  • PLIOLITE V.T.A.C. is a vinyl toluene/acrylate co- 5 polymer, KB value 36.
  • ESSO 100 Solvent is a hydrocarbon solvent supplied by Esso Chemicals Australia Limited, having an aromatic content of 98 percent, flash point of 108F., and
  • MICROLITH Pigments comprise a pigment and a resinous carrier.
  • Microlith Black pigment contains pure neutral carbon black together with a toluene soluble carrier resin such as Stabilite Ester 10 of the Hercules Powder Co., U.S.A.
  • MICROLITH BLUE 4GT comprises a stable phthalocyanine blue pigment with a greenish cast together with Stabilite Ester lO resin.
  • MICROLITI-I GREEN GT comprises a medium shade of phthalocyanine green together with Stabilite Ester 10 resin, the microlith pigments are manufactured by Ciba Co., Switzerland.
  • Coates hydrocarbon dispersible flake black comprises pure carbon black together with ethyl hydroxy cellulose resin.
  • GRAPI-ITOL BLUE BLF phthalocyanine blue
  • C.I. pigment blue made by Sandoz.
  • ISOL RUBY RED BKS 7520 (KVK) a lithol ruby red CI.
  • Pigment Red 57, Agfa, Calcium lake PALE LOWERING LITI-IOGRAPHIC VARNISH a polymerized linseed oil varnish made by Meggitts Ltd., Australia, Polylin /3, acid value 40-65 viscosity 7.0-9.5 poises at 25C, from alkali refined linseed oil.
  • RHODENE RESIN L42/70 a safflower oil modified alkyd resin made by Polymer Corporation, Australia, acid value 6-10, with 69-71, percent solids, 64 percent oil length.
  • ISOPAR G a hydrocarbon liquid solvent with greater than percent isoparaffinic content, and aromatics and olifins less than 1 percent, and remainder cyclo and normal paraffins, KB No. 27, final boiling point 177C.
  • ISOPAR E a hydrocarbon liquid solvent with greater than 95 percent isoparaffinic content, aromatics and olifins less than 1 percent with remainder cyclo and normal paraffins, KB Value 29, final boiling point 143C.
  • B880 100 is an aromatic hydrocarbon solvent with 98 percent aromatics, KB value 9', final boiling point 182C.
  • the method of developing electrostatic images wherein the electrostatic image is formed on a photoconductive surface which has light struck relatively conductive image areas and dark-adapted charge bearing areas, and wherein the liquid developer contains a carrier liquid having suspended in it a relatively insulating primary developer compound which is more insulating than a secondary more conductive developer compound also suspended in said carrier liquid, said primary compound having a polarity in said insulating carrier liquid which causes the primary developer to migrate to said charge bearing areas to develop the same by electrical attraction, the more conductive developer compound being particulate and closer in polarity to the charge bearing areas so that it can be urged away from said photo-conductor surfaces when a bias is applied through the said developer but is driven toward it when the polarity of the bias is reversed, said method comprising the steps of a.
  • the photoconductor is zinc oxide which is negatively charged and the first developer compound is a copolymeric resin having a relatively positive charge in an insulating carrier liquid, and the second developer compound is a particulate toner with an added medium to render the same conductive.
  • the photoconductor is one which can be negatively charged
  • the first developer compound is a copolymeric resin having a relatively positive charge in an insulating carrier liquid
  • the second developer is carbon black surrounded with a fixing resin and calcium octoate to render the same relatively conductive.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Liquid Developers In Electrophotography (AREA)
  • Wet Developing In Electrophotography (AREA)
US00294000A 1971-09-30 1972-10-02 Method of developing an electrophotographic image with a bias field Expired - Lifetime US3836361A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
AU647871 1971-09-30

Publications (1)

Publication Number Publication Date
US3836361A true US3836361A (en) 1974-09-17

Family

ID=3697017

Family Applications (1)

Application Number Title Priority Date Filing Date
US00294000A Expired - Lifetime US3836361A (en) 1971-09-30 1972-10-02 Method of developing an electrophotographic image with a bias field

Country Status (10)

Country Link
US (1) US3836361A (fr)
JP (1) JPS5525665B2 (fr)
BE (1) BE789560A (fr)
CA (1) CA971831A (fr)
DE (1) DE2247599A1 (fr)
FR (1) FR2250445A5 (fr)
GB (1) GB1401643A (fr)
IT (1) IT975132B (fr)
NL (1) NL7213205A (fr)
SE (1) SE383214B (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5220384A (en) * 1988-11-21 1993-06-15 Spectrum Sciences B.V. Liquid developer based imaging machine using a developing electrode
DE4325717A1 (de) * 1992-08-03 1994-02-10 Dispense A Bag Systems Ltd Spender

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4707572B2 (ja) * 2006-01-30 2011-06-22 中国電力株式会社 円筒形高圧カットアウト

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3010842A (en) * 1955-08-29 1961-11-28 Xerox Corp Development of electrostatic images
US3081263A (en) * 1956-12-21 1963-03-12 Secretary Of The Dept Of Suppl Precipitation of particulate or molecular materials in electrostatic developing
US3094429A (en) * 1959-07-31 1963-06-18 Burroughs Corp Method of electrostatic recording with different inkse
US3300410A (en) * 1961-03-13 1967-01-24 Australia Res Lab Conductive liquid developer for xerographic images
US3337340A (en) * 1961-12-28 1967-08-22 Australia Res Lab Method for the reproduction of color
US3679453A (en) * 1968-03-25 1972-07-25 Ricoh Kk Developing method and device therefor for use in wet type electronic or electrostatic photography

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3010842A (en) * 1955-08-29 1961-11-28 Xerox Corp Development of electrostatic images
US3081263A (en) * 1956-12-21 1963-03-12 Secretary Of The Dept Of Suppl Precipitation of particulate or molecular materials in electrostatic developing
US3094429A (en) * 1959-07-31 1963-06-18 Burroughs Corp Method of electrostatic recording with different inkse
US3300410A (en) * 1961-03-13 1967-01-24 Australia Res Lab Conductive liquid developer for xerographic images
US3337340A (en) * 1961-12-28 1967-08-22 Australia Res Lab Method for the reproduction of color
US3679453A (en) * 1968-03-25 1972-07-25 Ricoh Kk Developing method and device therefor for use in wet type electronic or electrostatic photography

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5220384A (en) * 1988-11-21 1993-06-15 Spectrum Sciences B.V. Liquid developer based imaging machine using a developing electrode
DE4325717A1 (de) * 1992-08-03 1994-02-10 Dispense A Bag Systems Ltd Spender
DE4325717C2 (de) * 1992-08-03 1998-10-08 Cascade Dispensers Ltd Spender

Also Published As

Publication number Publication date
CA971831A (en) 1975-07-29
BE789560A (fr) 1973-01-15
NL7213205A (fr) 1973-04-03
DE2247599A1 (de) 1973-04-12
IT975132B (it) 1974-07-20
FR2250445A5 (fr) 1975-05-30
JPS5525665B2 (fr) 1980-07-08
GB1401643A (en) 1975-07-16
JPS4857636A (fr) 1973-08-13
SE383214B (sv) 1976-03-01

Similar Documents

Publication Publication Date Title
US3337340A (en) Method for the reproduction of color
US3565805A (en) Electrostatic developer mix
US4135925A (en) Methods of changing color by image disruption
US5744269A (en) Method for protecting developed electrostatic images using an amphipathic toner
US3766072A (en) Edge and latitude developer
US3918966A (en) Liquid development of an electrical image in which a pulsating field is employed
US3729419A (en) Liquid developer
WO1998024002A9 (fr) Comment proteger des images electrostatiques au moyen d'un toner amphipatique
US4147812A (en) Electrophoretic development
US3244633A (en) Liquid developers for developing electrostatic images
US3836361A (en) Method of developing an electrophotographic image with a bias field
US3376133A (en) Multicolor electrostatic printing
US3793205A (en) Chargeless developer
US5839037A (en) Method for transferring a liquid image
US4113482A (en) Migration imaging method involving color change
US3300410A (en) Conductive liquid developer for xerographic images
US3881925A (en) Bi-chargeable electrophotographic materials including zinc oxide and a binder resin
US4985329A (en) Bipolar liquid electrostatic developer
US3793234A (en) Liquid developer composition
US3773507A (en) Electrophotographic reversal development process employing a pre-toner
US3971659A (en) Color electrophotographic process using photoconductive particles in liquid developer
US3505231A (en) Liquid developer for xerography
US5206107A (en) Siloxane surfactants as liquid developer additives
US3836381A (en) Method of developing a dielectric pattern on a semiconductor surface using a two-component developer
US3528097A (en) Liquid developers for developing electrostatic images