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US3001888A - Method of developing an electrostatic image - Google Patents

Method of developing an electrostatic image Download PDF

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Publication number
US3001888A
US3001888A US763016A US76301658A US3001888A US 3001888 A US3001888 A US 3001888A US 763016 A US763016 A US 763016A US 76301658 A US76301658 A US 76301658A US 3001888 A US3001888 A US 3001888A
Authority
US
United States
Prior art keywords
developer
liquid
carrier
phase
globules
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
US763016A
Other languages
English (en)
Inventor
Kenneth Archibald Metcalfe
Robert John Wright
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.)
Australian Government
Original Assignee
Australian Government
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
Priority claimed from AU31956/57A external-priority patent/AU219056B2/en
Application filed by Australian Government filed Critical Australian Government
Priority to US139504A priority Critical patent/US3212916A/en
Application granted granted Critical
Publication of US3001888A publication Critical patent/US3001888A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • 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
    • 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

Definitions

  • This invention relates to emulsion developers for electrostatic images.
  • Development of electrostatic images is at the present time effected principally by three methods, the first of these consisting of the use of dry powders which are dusted onto the image and are subsequently fixed by heating or the like, the second method consisting of the use of a cloud of developer, the third method consisting of the use of liquids which carry the developer material.
  • a liquid developer should preferably be of such a nature that, while it allows free movement of the developer materials to the site where they are to be deposited, it should not be dangerous from the viewpoint of fire or explosion. Most of the liquid developers, however, have characteristics such that under suitable conditions they might be inflammable.
  • the object of the present invention is to improve developers so that this risk can be controlled or entirely removed, a further object being to provide certain im provements to known processes of liquid development such as more rapid development and better means of controlling the density or tone.
  • the present invention also envisages the use of a carrier phase for the developer, but instead ofusing a solid medium, the carrier is according to our invention a liquid or a gas of such surface tension that the developer can be carried on the surface of its globules and can thereby be deposited onto an electrostatic image as the carrier moves the developer in contact with it.
  • An emulsion developer for electrostatic images can therefore comprise a liquid carrier phase and a liquid developer phase, the liquid carrier phase being immiscible with the liquid developer phase,
  • liquid carrier phase having a surface tension such that the liquid developer phase is carried on the surface of globules of the said liquid carrier phase when shaken up to produce an emulsion.
  • an emulsion developer for electrostatic images comprises a carrier phase and a developer phase, said carrier phase consisting of a non-inflammable liquid such as water, said developer phase comprising a non-polar liquid having a volume resistivity of not less than ohm-centimeter and a dielectric constant of not greater than three Patented Sept. 26, 1961 said developer substance having a pigment substance such and immiscible with the said carrier phase liquid such as v cyclohexane or mineral turpentine or kerosene or xylene,
  • phthalocyanine blue suspended in it on the particles of which is a coating forming a control and fixing agent such as a resin or an oil which is only sparingly soluble in the developer liquid or remains deposited on the surface of the pigment substance when the carrier liquid is evaporated whereby, when the liquids are shaken up to produce an emulsion, the globules of the said carrier phase liquid have a film of the developer phase held thereto by ionic attraction but removable therefrom by the field of an electrostatic image.
  • a control and fixing agent such as a resin or an oil which is only sparingly soluble in the developer liquid or remains deposited on the surface of the pigment substance when the carrier liquid is evaporated whereby, when the liquids are shaken up to produce an emulsion, the globules of the said carrier phase liquid have a film of the developer phase held thereto by ionic attraction but removable therefrom by the field of an electrostatic image.
  • an aqueous or non-inflammable developer carrier can be used, it being for instance neces saryonly to combine a developer with water which, when shaken up, will cause the globules of the water tobe coated with the developer.
  • ' veloper phase can be carried across the surface by the liquid carrier phase.
  • the developer tray depicted in FIG. 1 comprises a tray 1 onto which the paper 2 to be developed is placed, the tray 1 being housed in a casing 3 in which the tray 1 is arranged with a slight downward slope to cause the developer to flow across the tray 1 in one direction.
  • the casing 3 contains a developer tank 4 which carries in it the developer liquid 5 to the level indicated by 6.
  • a pump 7 is provided the rotor 8 of which can be driven in any suitable manner, the pump 7 being connected to the developer tank 4 by an intake duct 9 which allows the developer to flow into the pump, the developer being displaced by the pump flowing up the duct 10 to a two-part duct 11-12, the two-part duct being divided by a directmg vane 13 which can be placed either into the position shown in FIG. 1 or which can be swung over towards the left.
  • the part 11 of the two-part duct is disposed to feed liq uid developer displaced by the pump 7 back into the developer tank 4 and when the mechanism is set in the manner indicated, operation of the pump 7 will circulate the two phase developer continually through the tank and in path of the dotted arrows in the duct 12 into the nozzle 8 14 and from there will issue across the paper 2 and the tray 1 in the direction of the dotted arrows, the developer 3 leaving the tray 1 through the gap 16 between its end and the wall of the developer tank 4.
  • the developer can be maintained in an emulsified state by circulating the developer through the pump and the developer tank 4 in the direction of the full line arrows shown in the drawings, and at this stage no flow will take place across the tray 1 from the nozzle 14.
  • a paper to be developed can then be simply placed into position as shown, preferably by engaging its leading edge into a notch 17 of the tray 1 and the directing vane 13 is then simply swung over to the other position and the emulsified developer will be pumped through the nozzle 14, out of the openings 15 to flow rapidly across the surface of the paper being developed and the tray and back into the developer tank 4, the directing vane 13 being simply swung back to its other position immediately development has been completed which it will be found can take place in a matter of a few seconds, the paper being then simply removed and if an appropriate liquid developer has been used it will be found that the image is dry, or practically dry, the liquid developer phase which coats the aqueous carrier phase globules preventing wetting of the image by water.
  • the paper is again represented by the numeral 2 but the liquid phase is designated while the developer phase is designatedll, the globules of the liquid 20 moving the developer phase 21 across the surface 2, it being desirable to have an excess of the developer phase present so that as the film which is held to the water globules by the ionic force, which is less than the electrostatic force on the paper, can be replaced on the surface of the globules during development of an image, for it is found that if insufficient developer is present to maintain a coating on the globules 20, that the globules in contacting the electrostatic image onthe paper will tend to destroy the image as they are then not separated by the insulated coating of the developer from the non-insulating water carrier.
  • the proportion of the developer phase to the carrier phase can be tested by checking to insure that during development sutlicient globules are not stripped" of their developer coating to allow these to combine and form larger globules.
  • Developer paste Fifteen grams of a phenol modified penta-erythritol ester of rosin such as that known under the trade name Pentarol 20" (acid value 7-15, specific gravity at 20 C. 1.09) is digested in twenty-five grams of xylene and when solution is completed fifteen grams of a linseed oil modified alkyd resin of medium length such as that known under the trade name Rhodene L6/ 100 (oil length 52%, acid value 6-10, specific gravity at 20 C., 0.955 to 0.965) is added.
  • a phenol modified penta-erythritol ester of rosin such as that known under the trade name Pentarol 20" (acid value 7-15, specific gravity at 20 C. 1.09) is digested in twenty-five grams of xylene and when solution is completed fifteen grams of a linseed oil modified alkyd resin of medium length such as that known under the trade name Rhodene L6/ 100 (oil length 52%,
  • phthalocyanine blue is then mixed with the above mixture and blended either in a ball. mill or triple roll mill until. mixing is complete and pigment particle size is reduced to the required fineness, such as 0.5- micron, average. For the most purpose eight hours milling in a ball mill should be sufiicient.
  • the pigment particles carry a coating, either continuous or discontinuous, of the coatingmix, which will influence the surface charge of;
  • the paste so produced is used as the basis for a dispersion in a liquid of high volume resistivity having a zeta potential greater than the ionic potential of the liquid, dispersion being etfected by stirring a small portion of the paste into the required liquid, which in this case may be kerosene, and straining to remove portions of paste that have not completely dispersed.
  • Paste concentration The concentration of the dispersion may be varied at will but a typical concentration of a preferred dispersion is to utilize 0.5 gram of developer paste in mils of liquid.
  • Carrier liquid A liquid developer produced in this way, in which particles are coated with a charge controlling and fixing agent which is only sparingly soluble in the high resistivity liquid or remains as a coating for the particles when the liquid of the developer phase is evaporated, is then mixed in the proportion of 100 cc. of the liquid developer to 100 cc. of water, it being then found that the kerosene base developer will be immiscible with the water but on agitation the water will be broken up into globules which will be coated with the liquid developer. The developer is then ready for use in the manner described earlier herein.
  • Globule size As a guide to the size of the globules these can conveniently range from approximately of an inch in diameter to /8 of an inch in diameter although these dimensions' are not particularly critical, but it is found that as the globules are of smaller size, the total mixture has a lower volume resistivity with quicker destruction of the electrostatic image during development, the particle size thus affording a degree of control of the time of development, that is the time during which development can take place before the electrostatic image is destroyed by the absorption of developer particles and the presence of the electrically conducting water globules.
  • Soap emulsifiers and similar material may be used to increase the emulsification provided they are non-ionic, or if ionic, are such that they do not reduce the volume resistivity of the mixture below 10 ohm-centimeter or the dielectric constant above three. Examples of these are gum-arable, selenium derivatives, glycol and permanganate.
  • the thickness of the developer coating on the carrier globules, and the resistivity of the developer liquid itself will provide further control means.
  • the present invention resides in the use of a developer which forms the phase, the other phase being a substance which no miscible with the developer so that the developer ves to coat globules of the carrier, which, as said, can then act mechanically to convey the developer to the site, while at the same time controlling the rate of bleedoif of the image charge and serving to reduce or counter the inflammability of the usually more volatile liquid which forms the suspending medium for the pigment and the fixing resin or oil or other substance.
  • the globules of the carrier phase have deformable walls allows them to accommodate them selves more readily to surface inequalities in the medium being developed and thus greatly improves the process over the dry developer and rigid bead system.
  • the developer must be prepared to insure that the developer material such as pigment, remains in the outer phase where it will be the contacting medium when the developer is in use, but this can readily be achieved by first suspending the pigment and resin or other bonding agent in a liquid of suitable high electrical resistivity and then adding the liquid or gaseous carrier phase which, on agitation, will form the carrier globules with the developer coating surrounding same.
  • the emulsion developer so formed is simply contacted with the image, and the coated pigment particles which are free to move in the liquid, deposit on those areas of the image where a suitable potential exists, until the charge of the image has been satisfied by the particles deposited, the particles being held in position by the electrical force until the carrier liquid is evaporated, whereupon the pigment particles are held by direct adhesion of the resin or other bonding substance on the surface of the particles.
  • the coating mix is only partly soluble in the carrier liquid, and therefore, while the partly dissolved surface of the coating is in a condition where it will form an effective bonding medium after evaporation of the solvent, it will act as a surface charge modifier during development to control the migration of the particals in an electrical field.
  • the developer of the example can be modified by replacing the Rhodene L6/100 with an equal percentage of Pentarol 20, whereupon it will be found that the developer will have good fixing qualities but will not have the same degree of modification of the surface charge of the pigment particles as the Pentarol 20 is relatively soluble in the carrier liquid and is a tacky substance, so that it tends to leave the pigment particles when in the developer and deposit as a fixing substance.
  • the develop er can be said to have both a charge modifying agent and a fixing agent.
  • the developer can also have the Pentarol 20 replaced by an equal percentage of Rhodene L6/100 a substance less soluble in the carrier liquid specified and the developer then acts as one with a high degree of control of the surface charge of the pigment particles due to the coating substance remaining on the pigment particles with possibly even so little solubility on the surface that no appreciable binding of the particles will take place after evaporation of the carrier liquid.
  • a method of developing an electrostatic image which comprises applying to a body having a latent electrostatic image thereon an emulsion formed by: mixing a pigment in a liquid to form a developer and placing the developer in a carrier liquid with which the developer is immiscible to form an emulsion of the developer and carrier liquid in which the developer coats globules of said carrier liquid.
  • a method as defined in claim 1 further comprising continuously mixing the carrier liquid and developer and applying the resulting emulsion to said body.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Liquid Developers In Electrophotography (AREA)
  • Wet Developing In Electrophotography (AREA)
US763016A 1957-09-25 1958-09-24 Method of developing an electrostatic image Expired - Lifetime US3001888A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US139504A US3212916A (en) 1957-09-25 1961-09-20 Method of developing electrostatic image with foam liquid developer

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
AU31956/57A AU219056B2 (en) 1957-10-09 Improvements relating to fluid pressure actuated control apparatus

Publications (1)

Publication Number Publication Date
US3001888A true US3001888A (en) 1961-09-26

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ID=3719579

Family Applications (1)

Application Number Title Priority Date Filing Date
US763016A Expired - Lifetime US3001888A (en) 1957-09-25 1958-09-24 Method of developing an electrostatic image

Country Status (5)

Country Link
US (1) US3001888A (de)
CH (1) CH381527A (de)
DE (1) DE1097269B (de)
FR (1) FR1212255A (de)
GB (1) GB902928A (de)

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3068115A (en) * 1961-02-06 1962-12-11 Xerox Corp Electrostatic emulsion development
US3129115A (en) * 1961-04-17 1964-04-14 Xerox Corp Xerographic developing apparatus
US3212916A (en) * 1957-09-25 1965-10-19 Commw Of Australia Method of developing electrostatic image with foam liquid developer
US3241957A (en) * 1961-06-08 1966-03-22 Harris Intertype Corp Method of developing electrostatic images and liquid developer
US3249088A (en) * 1963-04-03 1966-05-03 Scm Corp Developing tank unit for electrostatic printing
US3251687A (en) * 1961-07-10 1966-05-17 Itek Corp Electrostatic printing process
US3256197A (en) * 1958-09-23 1966-06-14 Harris Intertype Corp Liquid developer for electrostatic charge images
US3285741A (en) * 1961-04-19 1966-11-15 Agfa Gevaert Nv Process for developing electrostatic latent images
US3319546A (en) * 1962-05-18 1967-05-16 Rca Corp Electrostatic printing apparatus
US3336906A (en) * 1965-06-09 1967-08-22 Fairchild Camera Instr Co Apparatus for immersion development
US3486922A (en) * 1967-05-29 1969-12-30 Agfa Gevaert Nv Development of electrostatic patterns with aqueous conductive developing liquid
US3498917A (en) * 1965-10-23 1970-03-03 Philips Corp Liquid developer for electrostatic images
US3507679A (en) * 1964-03-23 1970-04-21 Commw Of Australia Controlled polarity liquid developer
US3566834A (en) * 1967-08-14 1971-03-02 Fuji Photo Film Co Ltd Electrophotographic developing device
US3570456A (en) * 1969-02-11 1971-03-16 Varian Associates Liquid development apparatus for development of electrostatic images
US3625897A (en) * 1968-06-19 1971-12-07 Ricoh Kk Liquid developing agent for electrophotography
US3627410A (en) * 1968-02-08 1971-12-14 Xerox Corp Reproduction appratus with liquid developer
US3668126A (en) * 1967-01-20 1972-06-06 Fuji Photo Film Co Ltd Method of producing electrophotographic liquid developers having very fine coloring material
US3862618A (en) * 1972-11-09 1975-01-28 Xerox Corp Liquid developing apparatus for developing an electrostatic image
US3885960A (en) * 1972-12-11 1975-05-27 Bell & Howell Co Method of development of liquid electrostatic images using an hydrophobic barrier liquid
US3976583A (en) * 1972-12-21 1976-08-24 Hoechst Aktiengesellschaft Electrophotographic developer liquid
US4043658A (en) * 1969-09-25 1977-08-23 Canon Kabushiki Kaisha Electrophotographic photosensitive member

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3155531A (en) * 1958-09-23 1964-11-03 Harris Intertype Corp Meagnetic liquid developer and method for electrostatic images

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1545870A (en) * 1923-10-29 1925-07-14 Edzell N Wyllie Polish for automobiles, furniture, etc.
US2171851A (en) * 1936-11-19 1939-09-05 Herman B Kipper Process for the manufacture of paints
US2537055A (en) * 1947-09-24 1951-01-09 Shell Dev Aqueous emulsion paints
US2877133A (en) * 1956-10-22 1959-03-10 Gen Dynamics Corp Electrostatic photography

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1545870A (en) * 1923-10-29 1925-07-14 Edzell N Wyllie Polish for automobiles, furniture, etc.
US2171851A (en) * 1936-11-19 1939-09-05 Herman B Kipper Process for the manufacture of paints
US2537055A (en) * 1947-09-24 1951-01-09 Shell Dev Aqueous emulsion paints
US2877133A (en) * 1956-10-22 1959-03-10 Gen Dynamics Corp Electrostatic photography

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3212916A (en) * 1957-09-25 1965-10-19 Commw Of Australia Method of developing electrostatic image with foam liquid developer
US3256197A (en) * 1958-09-23 1966-06-14 Harris Intertype Corp Liquid developer for electrostatic charge images
US3068115A (en) * 1961-02-06 1962-12-11 Xerox Corp Electrostatic emulsion development
US3129115A (en) * 1961-04-17 1964-04-14 Xerox Corp Xerographic developing apparatus
US3285741A (en) * 1961-04-19 1966-11-15 Agfa Gevaert Nv Process for developing electrostatic latent images
US3241957A (en) * 1961-06-08 1966-03-22 Harris Intertype Corp Method of developing electrostatic images and liquid developer
US3251687A (en) * 1961-07-10 1966-05-17 Itek Corp Electrostatic printing process
US3319546A (en) * 1962-05-18 1967-05-16 Rca Corp Electrostatic printing apparatus
US3249088A (en) * 1963-04-03 1966-05-03 Scm Corp Developing tank unit for electrostatic printing
US3507679A (en) * 1964-03-23 1970-04-21 Commw Of Australia Controlled polarity liquid developer
US3336906A (en) * 1965-06-09 1967-08-22 Fairchild Camera Instr Co Apparatus for immersion development
US3498917A (en) * 1965-10-23 1970-03-03 Philips Corp Liquid developer for electrostatic images
US3668126A (en) * 1967-01-20 1972-06-06 Fuji Photo Film Co Ltd Method of producing electrophotographic liquid developers having very fine coloring material
US3486922A (en) * 1967-05-29 1969-12-30 Agfa Gevaert Nv Development of electrostatic patterns with aqueous conductive developing liquid
US3566834A (en) * 1967-08-14 1971-03-02 Fuji Photo Film Co Ltd Electrophotographic developing device
US3627410A (en) * 1968-02-08 1971-12-14 Xerox Corp Reproduction appratus with liquid developer
US3625897A (en) * 1968-06-19 1971-12-07 Ricoh Kk Liquid developing agent for electrophotography
US3570456A (en) * 1969-02-11 1971-03-16 Varian Associates Liquid development apparatus for development of electrostatic images
US4043658A (en) * 1969-09-25 1977-08-23 Canon Kabushiki Kaisha Electrophotographic photosensitive member
US3862618A (en) * 1972-11-09 1975-01-28 Xerox Corp Liquid developing apparatus for developing an electrostatic image
US3885960A (en) * 1972-12-11 1975-05-27 Bell & Howell Co Method of development of liquid electrostatic images using an hydrophobic barrier liquid
US3976583A (en) * 1972-12-21 1976-08-24 Hoechst Aktiengesellschaft Electrophotographic developer liquid

Also Published As

Publication number Publication date
GB902928A (en) 1962-08-09
DE1097269B (de) 1961-01-12
CH381527A (fr) 1964-08-31
FR1212255A (fr) 1960-03-23

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