US3815545A - Electrophotograph developing apparatus - Google Patents

Electrophotograph developing apparatus Download PDF

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Publication number
US3815545A
US3815545A US00201644A US20164471A US3815545A US 3815545 A US3815545 A US 3815545A US 00201644 A US00201644 A US 00201644A US 20164471 A US20164471 A US 20164471A US 3815545 A US3815545 A US 3815545A
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United States
Prior art keywords
roller
sheet material
latent image
electrophotographic
electrophotographic sheet
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Expired - Lifetime
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US00201644A
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English (en)
Inventor
M Sato
T Komaki
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Fujifilm Holdings Corp
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Fuji Photo Film Co Ltd
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Publication date
Application filed by Fuji Photo Film Co Ltd filed Critical Fuji Photo Film Co Ltd
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Publication of US3815545A publication Critical patent/US3815545A/en
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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 Cl........ 1n liquid electrophotographic developing apparatus wherein the electrophotographic material is passed between a series of roller pairs, in at least the first roller pair the roller facing the latent image on the electro- 30%,. m he m3D 8 1 E, 6 9 L 5 7 .Q B 8 7 7 m 3 6 n" .u m 1 mm r um um um d Ld .mF
  • 117/37 LE; 355/10; 95/89 R, 89 L' photographic material is of an insulating material or References Cited UNITED STATES PATENTS coated with an insulating material, the remaining roller pair(s) being development rollers.
  • This invention relates to electrophotograph developing apparatus using a liquid developer, and more particularly it relates to the improvements in such apparatus in which the electrophotographic material sheet is continuously fed while seized by plural pairs of rollers.
  • FIG. 1 is a sectional view of an embodiment of a conventional developing device in which'the electrophotographic material is fed while being seized or held by roller pairs.
  • FIG. 2 shows the distribution of electric charges on the electrophotographic material and the distribution of the electric field in a direction vertical to the latent image surface.
  • FIG. 3 is a schematic sectional view of an embodiment of apparatus according to the present invention.
  • FIG. 1 shows a schematicsectional view of a conventional developing apparatus in which the photographic material is fed while being seized by roller pairs.
  • Such apparatus is, for instance, disclosed in Japanese Patent Patent Publication No. 41-9476.
  • numeral designates an electrophotographic sheet material having'an electrostatic latent image thereon
  • 11 and 12 denote, respectively, developing rollers disposed on opposing faces of the electrophotographic material sheet.
  • Cooperating pairs of rollers are made of metal and are adapted to feed the photographic material sheet by seizing or holdinglthe latter in the manner as shown.
  • the rollers 11 are adapted to double as developing electrodes, and may be in contact with or slightly spaced apart from the latent image surface.
  • Numeral l3 denotes the nozzles for supplying the liquid developer to the latent image surface.
  • Theliquid developer is first sprayed against the rollers 11.
  • the roller pairs are driven in the directions indicated by arrows by a suitable driving means not shown.
  • the apparatus shown in FIG. 1 is excellent in many respects for use as an electrophotographic developing apparatus using a liquid developer, it has the following defects.
  • FIG. 2 shows the electric charge distribution (A) in the latent image, the electric field distribution (B) in a direction vertical to the latent image surface when no developing electrode is present, and the electric field distribution (C) in a direction vertical to the latent image when the developing electrodes are present.
  • the axis of the abscissa represents the position along a straight line on the electrophotographic material sheet. It is assumed that the electric charges are present uniformly over the entire range on the left side of the origin 0, that the developer is flown from left to right as shown by arrow 20, and that the latent image has the positive charges and the toner has the negative charges.
  • the electric field exhibits the characteristic shown by curve C.
  • the optimum time at which the developing electrodes are used cannot be definitely stated as it varies according to the particular developer and the photographic material used, but experimentally it has been found preferable to use the developing electrodes after reaching the stage where the toner is sufficiently deposited in the area where the electric charges are present and there remains almost no force which acts to attract the toner to the latent image surface.
  • Such operation is conducted on a limited scale in the apparatus of FIG. ll, i.e., the developer is supplied on the latent image surface with no developing electrode being present.
  • the electrophotographic material is moving in the direction of arrow 15 and is therefore immediately brought into a face-to-face relationship with the first developing electrode (roller ll-ll).
  • the time in which the development is conducted in the absence of the first developing electrode is preferably within the range of from about 2 to about seconds. A shorter time than the above range may give rise to streaks, while a longer time, though producing no streaks, will elongate the total process time. If total process time is of no concern, the developing operation may be conducted without the use of any developing electrode for an even longer period.
  • rollers 3l-.-1 and 312 are the rollers which characterize the present invention.
  • Rollers 3ll-l and 31-2 are either made of an insulating material or formed by coating the surface of a metal roller with a highly insulating material so that they will not serve as developing electrodes.
  • Rollers 32-1 and 32-2 correspond to roller ll2-l, and are metal rollers.
  • Rollers 31-1 and 311-2 may'be made of insulating plastics such as acrylic resins, polyamides, polyvinyl chlorides, polyethylene fluorides or the like, or may be formed by coating a metal roller with such an insulating resin.
  • insulating plastics such as acrylic resins, polyamides, polyvinyl chlorides, polyethylene fluorides or the like, or may be formed by coating a metal roller with such an insulating resin.
  • both rollers 3l-ll and 31-2 may be metal rollers with no coating thereon, provided that they are arranged with a sufficiently large spacing between them and the latent image surface.
  • such arrangement invites leakage of the developer from the space between the roller 3ll-l and the latent image surface, and the liquid that leaks out may flow onto the electrophotographic sheet material in a direction contrary to the traveling direction of said sheet material or may flow over the outside of the apparatus.
  • the roller 3lll is so designed as to perform the role of preventing the developer from flowing away from contact with the developing sheet.
  • Roller 3l2 may be made of metal and arranged with an accordingly increased spacing from the latent image surface.
  • the spacing should preferably be more than 2 mm.
  • letter L indicates the area where develop ment is conducted without using developing electrodes and letter L; the area where development is conducted using developing electrodes. It is possible to employ a greater number of insulating rollers. The greater the number of insulating rollers the faster the velocity at which the electrophotographic sheet material is fed.
  • the present invention is thus directed towards the use of a roller made of insulation or an insulation coated roller so that the development is carried under no development or under a negligible electrode effect at the initial development stage.
  • the roller 3l-1 can thus be made of an insulating material and roller 32-1 can be made of metal or an insulating material.
  • the electrophotographic sheet material used was prepared by coating a paper sheet with a kneaded mixture of photoconductive zinc oxide powder and an insulating resin.
  • Rollers l1, l2 and 32 were stainless steel rollers having a diameter of 18 mm, and rollers 31 were formed of acrylic resin having a diameter of 18 mm.
  • rollers 31 were prepared by coating a 16 mm diameter stainless steel roller with 1 mm thick layer of Teflon (trademark for a polyfluorocarbon product produced by Du Po'nt Chemical Co.).
  • the developer was prepared by suspending fine charged particles in an insulating solution formed of non-polar hydrocarbons and halogenated hydrocarbons. To be more definite, the developer was prepared by suspending carbon black in kerosene and dissolving therein as a dispersion stabilizer a resin material which is soluble in kerosene. The electrophotographic material was negatively charged while the toner was positively charged. The space between each adjoining roller was 4 mm. When 4 pairs of insulating rollers were used, no streaks were produced even when the feed velocity of the electrophotographic material was more than 10 cm/sec.
  • a preferred embodiment of the present invention comprises a roller assembly consisting of 8 to 10 pairs ofinsulating developing rollers and 8 to 10 pairs of metallic developing rollers, the rollers being arranged so that the space between each roller and the latent image surface is about 0.1 to about 0.5 mm. According to this embodiment, it is possible to carry out developing at an electrophotographic sheet material velocity of 5 to 10 cm/sec.
  • the roller which is facing the latent image is a metal roller
  • the roller works as development electrode if the roller is insulated or not from the other components.
  • the roller on the opposite side of the sheet may be a metal roller or a roller made of insulation, though it is preferably a metal roller due to the developing speed.
  • the process is continuous from area (L,) where the development is conducted without electrodes to area (L where development is conducted using developing electrodes
  • a transfer may be effected in a stepwise manner.
  • the thickness of the insulator on the rollers may be gradually reduced or the volume resistivity of the insulatormay be gradually reduced in the direction of the sheet flow. The end effect is thus to incrementally increase the developing electrode effect.
  • the passage of the electrophotographic sheet material may be either rectilinear or curvilinear during development.
  • roller 31-2 may be omitted in FIG. 3.
  • the sheet will be floated up between the rollers 31-1 and 11-1, causing the latent image face to hit against the surface of the roller 11-].
  • Such a problem tends to take place particularly when the electrophotographic material sheet curls its latent image surface toward the outside.
  • the present invention which is provided with insulating roller 31-2, the sheet is seized by said roller before the end of the sheet floats up to any troublesome degree, and this problem is not encountered.
  • the roller 11-] works as a development electrode, that is, the roller pair 11-1/ 12-1 is the metal roller pair.
  • the roller pair 31-2/32-2 is not necessary when the distance between the roller pairs 31-1/32-1 and 11-1/- 12-1 is small, so far as the sequential proceeding of the electrophotographic materials are not obstructed between these roll pairs.
  • the roller pairs also work as guides for the materials.
  • a'number of said plural roller pairs succeeding said one insulating roller pair each include one insulating roller or insulationcoated conductive roller facing the latent image side of said electrophotographic sheet material so that development with negligible development electrode effect occurs at all of said last mentioned number of said plu- .ment electrode effect occurs at all of said first half of the plural roller pairs.
  • rollers facing the latent image are spaced between about 0.1 and about 0.5 mm therefrom.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Wet Developing In Electrophotography (AREA)
  • Dry Development In Electrophotography (AREA)
US00201644A 1970-11-25 1971-11-24 Electrophotograph developing apparatus Expired - Lifetime US3815545A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP10395670A JPS5440940B1 (enrdf_load_stackoverflow) 1970-11-25 1970-11-25

Publications (1)

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US3815545A true US3815545A (en) 1974-06-11

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Family Applications (1)

Application Number Title Priority Date Filing Date
US00201644A Expired - Lifetime US3815545A (en) 1970-11-25 1971-11-24 Electrophotograph developing apparatus

Country Status (10)

Country Link
US (1) US3815545A (enrdf_load_stackoverflow)
JP (1) JPS5440940B1 (enrdf_load_stackoverflow)
AU (1) AU460882B2 (enrdf_load_stackoverflow)
BE (1) BE775797A (enrdf_load_stackoverflow)
CA (1) CA949308A (enrdf_load_stackoverflow)
DE (1) DE2158558A1 (enrdf_load_stackoverflow)
FR (1) FR2115982A5 (enrdf_load_stackoverflow)
GB (1) GB1334883A (enrdf_load_stackoverflow)
IT (1) IT945140B (enrdf_load_stackoverflow)
NL (1) NL7116205A (enrdf_load_stackoverflow)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3893417A (en) * 1974-01-17 1975-07-08 Eastman Kodak Co Apparatus for liquid development of electrostatic images
US4111156A (en) * 1974-12-09 1978-09-05 Olympus Optical Co., Ltd. Devices for developing an electrostatic charge image on a record sheet by a developer solution

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3155546A (en) * 1962-09-24 1964-11-03 Plastic Coating Corp Apparatus for the liquid toning of latent electrostatic images
US3301156A (en) * 1964-01-13 1967-01-31 Peerless Photo Products Inc Processing mechanism
US3328193A (en) * 1962-10-02 1967-06-27 Australia Res Lab Method of and means for the transfer of images
US3345925A (en) * 1963-01-03 1967-10-10 Scm Corp Electrostatic printing and developing apparatus
US3368894A (en) * 1963-11-05 1968-02-13 Australia Res Lab Multiple copy printing method and apparatus
US3405683A (en) * 1963-06-22 1968-10-15 Azoplate Corp Apparatus for the development of latent electrostatic images
US3575101A (en) * 1967-09-01 1971-04-13 Eastman Kodak Co Method and apparatus for processing photographic material
US3667987A (en) * 1969-12-12 1972-06-06 Scm Corp Method of developing latent electrostatic images
US3685907A (en) * 1969-06-25 1972-08-22 Masamichi Sato Electrophotographic process

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3155546A (en) * 1962-09-24 1964-11-03 Plastic Coating Corp Apparatus for the liquid toning of latent electrostatic images
US3328193A (en) * 1962-10-02 1967-06-27 Australia Res Lab Method of and means for the transfer of images
US3345925A (en) * 1963-01-03 1967-10-10 Scm Corp Electrostatic printing and developing apparatus
US3405683A (en) * 1963-06-22 1968-10-15 Azoplate Corp Apparatus for the development of latent electrostatic images
US3368894A (en) * 1963-11-05 1968-02-13 Australia Res Lab Multiple copy printing method and apparatus
US3301156A (en) * 1964-01-13 1967-01-31 Peerless Photo Products Inc Processing mechanism
US3575101A (en) * 1967-09-01 1971-04-13 Eastman Kodak Co Method and apparatus for processing photographic material
US3685907A (en) * 1969-06-25 1972-08-22 Masamichi Sato Electrophotographic process
US3667987A (en) * 1969-12-12 1972-06-06 Scm Corp Method of developing latent electrostatic images

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3893417A (en) * 1974-01-17 1975-07-08 Eastman Kodak Co Apparatus for liquid development of electrostatic images
US4111156A (en) * 1974-12-09 1978-09-05 Olympus Optical Co., Ltd. Devices for developing an electrostatic charge image on a record sheet by a developer solution

Also Published As

Publication number Publication date
AU3617571A (en) 1973-05-31
GB1334883A (en) 1973-10-24
BE775797A (fr) 1972-03-16
CA949308A (en) 1974-06-18
AU460882B2 (en) 1975-05-08
DE2158558A1 (de) 1972-06-08
JPS5440940B1 (enrdf_load_stackoverflow) 1979-12-06
NL7116205A (enrdf_load_stackoverflow) 1972-05-29
IT945140B (it) 1973-05-10
FR2115982A5 (enrdf_load_stackoverflow) 1972-07-07

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