US3804062A - Electrophotographic developing device - Google Patents

Electrophotographic developing device Download PDF

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Publication number
US3804062A
US3804062A US00092976A US9297670A US3804062A US 3804062 A US3804062 A US 3804062A US 00092976 A US00092976 A US 00092976A US 9297670 A US9297670 A US 9297670A US 3804062 A US3804062 A US 3804062A
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United States
Prior art keywords
liquid developer
belt
endless belt
sensitive material
liquid
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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
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US00092976A
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English (en)
Inventor
O Fukushima
M Sato
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.)
Fujifilm Holdings Corp
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Fuji Photo Film Co Ltd
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Filing date
Publication date
Application filed by Fuji Photo Film Co Ltd filed Critical Fuji Photo Film Co Ltd
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Publication of US3804062A publication Critical patent/US3804062A/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

  • An electrophotographic developing device comprising an electroconductive endless belt driven in a substantially horizontal plane, means for forwarding a flexible electrophotographic sensitive material carrying thereon an electrostatic latent image onto the upper surface of the endless belt at substantially the same speed and in the same direction as the belt, and a means for supplying a liquid developing agent to the opening between the endless belt and the electrophotographic sensitive material so that the liquid developing agent is retained between the endless belt and the electrophotographic sensitive material and conveyed therebetween so that the agent develops the electrostatic latent image on the electrophotographic sensitive material.
  • FIG. 1 and FIG. 2 are schematic diagrams showing conventional typical developing methods
  • FIG. 3, FIG. 4, and FIG. 6 are side elevations in longitudinal section of the developing device according to the present invention
  • FIG. is an oblique diagram showing one example of the endless belt to be used for the device of this invention.
  • This invention relates to a liquid developing device for electrophotography. More particularly, it relates to a developing device which is suitable for high-speed development and unproductive of streaking of image.
  • the first difficulty is encountered in the fact that reduced developing period fails to provide sufficient developing density and tends to produce the phenomenon of edge effect.
  • This shortcoming is particularly conspicuous in case of the reproduction of images of continuous gradation. Elimination of this shortcoming calls for a certain extent of elongation of the developing time.
  • the second difficulty is found in the phenomenon that increased developing speed results in the formation of a streaking in the developed image like the tail which follows a flying comet. Although what causes this phenomenon has not been clarified definitely, it has been learnt that the phenomenon fails to occur where the relative speed between the latent image surface and the developing liquid is small. In order for this difficulty to be overcome. it is necessary to minimize the relative speed occurring between the latent image surface and the developing liquid in the direction parallel to the latent image surface.
  • the present invention concerns a liquid developing device for electrostatic latent images, enjoying freedom from these shortcomings.
  • FIG. 1 illustrates a conventional manual method employed typically for developing images of continuous gradation.
  • the sheet 11 carrying a latent image thereon is disposed so as to allow the latent image plane to confront the developing electrode 12, with the liquid developing agent supplied to the opening between the sheet 11 and the developing electrode 12.
  • the liquid developing agent 14 is held in the container 13 and is allowed to flow down the opening 15 through gravitational pull. While the agent flows down the opening 15, the latent image is developed thereby. Thereafter, the agent is received in the container 16.
  • the liquid developing agent flows along the latent image surface, the developed image forms a streak in the direction in which the agent flows down. Such an image is quite unsightly and fails to provide an image of high quality.
  • FIG. 2 illustrates an example of the developing device which produces no relative speed between the latent image surface and the developing liquid and, consequently, produces no streak in the developed image.
  • the metallic drum 21 rotates in the direction indicated by the arrow mark 23 and the lower portion of the drum is kept submerged in the developing liquid 25 which is held in the container 24.
  • the drum 21 has a film of the developing agent formed on its surface as its lower portion comes into contact with the developing liquid and carries the film upward as it rotates.
  • the latent image sheet 11 advances in the direction indicated by the arrow mark 22, with the latent image surface looking downward.
  • the latent image surface is brought into contact with the film of the liquid.
  • the drum 21 also serves as the developing electrode.
  • the present invention provides a developing device which permits the development of image to be accomplished at a high speed without having to use a developing liquid with high concentration and high viscosity, with the developed image free from the phenomenon of streaking.
  • FIG. 3 is a schematic cross section of one preferred embodiment of the present invention.
  • 301 denotes a flexible endless belt at least one surface of which is electroconductive, and this belt is revolved along two rollers 302 and 303.
  • Concrete examples of the endless belt to be used are an endlessly shaped strip of plastic film having the surface thereof plated or vacuum deposited with a metallic substance, an electroconductive rubber belt, and a flexible metallic belt.
  • the endless belt is driven at a fixed speed in the direction indicated by the arrow mark 317.
  • the liquid developing agent 307 held in the container 306 is scooped up by the pump 304.
  • the liquid developing agent can be supplied uniformly onto the endless belt by shaping the discharge portion 305 of the pump in the form of a slit or of a series of small orifices.
  • the liquid developing agent which has been placed on the endless belt forms a flat, smooth film and, in that state, advances to the right together with the belt. While the liquid developing agent in practically a fixed film thickness is forwarded at practically a constant speed toward right, the sheet 308 which contains a latent image is sent between the pinch rollers 309 and 310 and then forwarded from upper left toward the endless belt surface at a certain angle with reference to the belt surface (which is virtually horizontal) at substantially the same speed as the driving speed of the endless belt.
  • the forward end of the sheet comes into contact with the surface of the endless belt slight to the right (forward) of the discharge portion 305 of the pump. Since the sheet is flexible, it begins to advance practically parallelly with the endless belt from that point of contact. Since the liquid developing agent is supplied at a fixed rate onto the endless belt before the sheet comes to confront the endless belt across a narrow opening, there is formed substantially a uniform depth ofliquid developing agent in the opening between the endless belt surface and the latent image surface. Further, the sheet and the endless belt are made to advance at practically the same speed while keeping the said layer of liquid. Consequently no streaking occurs in the developed image. Moreover, the time during which the latent image surface is held to confront the endless belt may be lengthened as desired by suitably selecting the length of the belt.
  • the endless belt serves as the developing electrode and, at the same time, as the carrier of the sheet.
  • the required developing density can be obtained easily by suitably selecting the toner concentration of the liquid developing agent. This is because, unlike the device shown in FIG. 2, this device does not suffer the liquid developing agent to flow down gravitationally.
  • the sheet which has undergone the step of development is passed between a pair of squeezing rollers 312 and 313 so as to be freed of the excess liquid developing agent adhering to the latent image surface.
  • the liquid developing agent which is remaining on the endless belt may he recovered in the container 306 so as to be put to reuse or it may be received in a separate container 315.
  • the liquid on the endless belt may be scraped out by means of a brush 314 or it may be removed by some other suitable device. Since the liquid 316 has a smaller toner concentration than the liquid developing agent 307, it may be discarded.
  • the liquid which has been removed by the squeezing rollers is likewise received in the container 315. It is effective for the elimination of fogging to wash, by a suitable method, the developed sheet prior to the step of squeezing, though not illustrated in FIG. 3. It is desirable that the pinch roller 310 is highly insulative and that either of the pair of pinch rollers 309 and 310 is made of a flexible substance.
  • the pinch roller 310 is desired to be coated with such porous material as sponge and impregnated with a highly insulative liquid, so that it will uniformly wet the latent image surface as the sheet passes the rollers (by way of prebath).
  • the blower 311 supply a current of air downward against the sheet. This method proves particularly important where the sheet is liable to curl or it is made of a paper of considerable thickness. This method is not required where the sheet is flat and smooth and is supple.
  • FIG. 4 shows another preferred embodiment of the present invention.
  • the supply roll 401 is used in the place of the pump. This supply roll is so disposed that the lower portion thereof is kept submerged in the liquid developing agent.
  • the liquid developing agent is allowed to adhere to the surface thereof and then scooped up.
  • the doctor blade 403 scrapes the liquid off the surface.
  • the liquid which has been scraped by the blade flows over the blade and reaches the endless belt.
  • the same performance as the pump may be obtained by suitably selecting the revolution number of the supply roll and the shape of the doctor blade.
  • the liquid developing agent may be supplied gravitationally from a tank positioned at an elevated level through a pipe onto the endless belt surface.
  • the spirit of the present invention resides in allowing a suffleient amount of liquid developing agent to be mounted on the endless belt by a suitable method without permitting the liquid to flow down the belt, causing the latent image surface to confront the belt from thereabove and, at the same time, driving the latent image surface, the liquid developing agent and the endless belt (serving as the developing electrode) at substantially the same speed.
  • FIG. 5 shows one form of the endless belt 301 to be used for the present invention.
  • the numeral 501 denotes the portion where the liquid developing agent is mounted in a uniform depth and made to confront the latent image surface.
  • the numeral 502 denotes an endless embankment provided along the edge of belt so as to prevent the liquid developing agent from falling off the side of belt. By incorporation of this means, sufficient amount of liquid developing agent can be held uniformly on the endless belt 501. From the characteristics of the present invention, the surface of the end less belt 501 is desired to be flat and smooth. lncorporation of meshes in the belt is not desirable from the standpoint of keeping the liquid in position.
  • an endless belt which is formed by overlaying an endless belt of metallic gauze or fabric material with a plastic endless belt which has the surface thereof plated or vacuum deposited with metallic substance or coated with an electroconductive paint.
  • the materials used for the endless belt are required to be resistant to the corrosive action of the liquid developing agent. Where plastic materials and rubber are used, attention must be paid to fulfilling this requirement.
  • the electroconductive layer is not always required to appear on the surface.
  • the electroconductive surface may be covered with a highly insulative liquid retaining material.
  • a highly insulative liquid retaining material For example fibers may be planted electrostatically densely to a depth of a small fraction of 1 mm up to 1 mm. Or, a porous layer of velvet, flannel, or sponge may be pased on the surface. Incorporation of such a liquid-retaining material serves to improve the retention of the liquid developing agent on the endless belt, making it possible to lower the concentration of liquid developing agent. It also serves to keep uniform the opening between the electrostatic latent image surface and the electroconductive portion of the endless belt.
  • FIG. 6 shows an example of the device using a plurality of endless belts.
  • 601 denotes a sheet holding an electrostatic latent image on the lower surface thereof
  • 602 a porous roller for providing prebath to the sheet 601, 602 and 603 a pair of pinch rollers, 604, 606 and 608 endless belts, 605, 607 and 609 rollers for holding the sheet against the upper surface of the endless belt, and 610 through 612 discharge portions for supplying the liquid developing agent onto the endless belts.
  • the numerals 613 and 614 denote sponges for wiping the liquid developing agent away the endless belts. In this device, supply and replacement of the liquid developing agent is accomplished advantageously to afford images of uniform image quality.
  • An electrophotographic developing device comprising an endless belt disposed about at least two rollers, at
  • said means for supplying the liquid developer including a supply roll partially disposed in a container of said liquid developer; means for rotating said supply roll to raise said developer liquid along the surface of said roll; and a plate having one end disposed adjacent said roll for removing said developer liquid therefrom and the other end thereof disposed over said endless belt so that the liquid developer removed from said roll flows over said endless belt to form said film; and
  • An electrophotographic developing device comprising an endless belt disposed about at least two rollers, at
  • means for driving said belt at a predetermined speed means for supplying liquid developer onto said enda less belt to form a film of said liquid developer on said belt, the inclination of said belt being such that said liquid developer does not flow down said belt but rather is carried along at said predetermined speed;
  • said latent image can be developed by liquid developer 1) in a short period of time without using a liquid developer of high concentration and low viscosity and (2) with minimal formation of the edge effect in half tone and continuous tone images because (a) there is minimal relative movement between the liquid developer and the electrophotographic sensitive material and (b) the liquid developer is held in contact with the sensitive material for a relatively long time proportional to the length of the endless belt.
  • An electrophotographic developing device comprising and endless belt disposed about at least two rollers,
  • said endless belt including raised portions disposed along the sides thereof to retain said liquid developer thereon;

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Wet Developing In Electrophotography (AREA)
  • Photographic Developing Apparatuses (AREA)
  • Photographic Processing Devices Using Wet Methods (AREA)
US00092976A 1969-11-27 1970-11-27 Electrophotographic developing device Expired - Lifetime US3804062A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP44095222A JPS4838261B1 (enrdf_load_stackoverflow) 1969-11-27 1969-11-27

Publications (1)

Publication Number Publication Date
US3804062A true US3804062A (en) 1974-04-16

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US00092976A Expired - Lifetime US3804062A (en) 1969-11-27 1970-11-27 Electrophotographic developing device

Country Status (7)

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US (1) US3804062A (enrdf_load_stackoverflow)
JP (1) JPS4838261B1 (enrdf_load_stackoverflow)
BE (1) BE759353A (enrdf_load_stackoverflow)
CA (1) CA923296A (enrdf_load_stackoverflow)
FR (1) FR2072381A5 (enrdf_load_stackoverflow)
GB (1) GB1302846A (enrdf_load_stackoverflow)
NL (1) NL7017291A (enrdf_load_stackoverflow)

Cited By (3)

* 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
US3913524A (en) * 1972-03-13 1975-10-21 Rank Xerox Ltd Liquid developing apparatus for electrophotography
US5488466A (en) * 1994-08-08 1996-01-30 Xerox Corporation Liquid development system

Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2431041A (en) * 1944-01-06 1947-11-18 Gen Aniline & Film Corp Mechanism for developing printed materials
US3192846A (en) * 1961-08-22 1965-07-06 Itek Corp Data processing apparatus
US3247825A (en) * 1963-04-23 1966-04-26 Ibm Wet diaphragm electrostatic printer
US3308737A (en) * 1963-06-18 1967-03-14 Fuji Photo Film Co Ltd Device for applying a treating solution to sensitized copying paper
US3363530A (en) * 1965-06-07 1968-01-16 Eastman Kodak Co Apparatus for processing film by means of a porous web solution applicator
US3367791A (en) * 1966-07-11 1968-02-06 Addressograph Multigraph Liquid development of electrostatic images
US3556050A (en) * 1968-06-24 1971-01-19 Eastman Kodak Co Liquid development apparatus
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
US3592678A (en) * 1968-03-28 1971-07-13 Xerox Corp Liquid donor development with electrophoretic cleaning
US3669073A (en) * 1969-04-04 1972-06-13 American Photocopy Equip Co Electrostatic developing system
US3687708A (en) * 1969-05-21 1972-08-29 Scm Corp Liquid development of latent electrostatic images

Patent Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2431041A (en) * 1944-01-06 1947-11-18 Gen Aniline & Film Corp Mechanism for developing printed materials
US3192846A (en) * 1961-08-22 1965-07-06 Itek Corp Data processing apparatus
US3247825A (en) * 1963-04-23 1966-04-26 Ibm Wet diaphragm electrostatic printer
US3308737A (en) * 1963-06-18 1967-03-14 Fuji Photo Film Co Ltd Device for applying a treating solution to sensitized copying paper
US3363530A (en) * 1965-06-07 1968-01-16 Eastman Kodak Co Apparatus for processing film by means of a porous web solution applicator
US3367791A (en) * 1966-07-11 1968-02-06 Addressograph Multigraph Liquid development of electrostatic images
US3566834A (en) * 1967-08-14 1971-03-02 Fuji Photo Film Co Ltd Electrophotographic developing device
US3592678A (en) * 1968-03-28 1971-07-13 Xerox Corp Liquid donor development with electrophoretic cleaning
US3556050A (en) * 1968-06-24 1971-01-19 Eastman Kodak Co Liquid development apparatus
US3570456A (en) * 1969-02-11 1971-03-16 Varian Associates Liquid development apparatus for development of electrostatic images
US3669073A (en) * 1969-04-04 1972-06-13 American Photocopy Equip Co Electrostatic developing system
US3687708A (en) * 1969-05-21 1972-08-29 Scm Corp Liquid development of latent electrostatic images

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Liquid Crystal Electrophotographic Display by R. Keyes, IBM Digest, Vol. 12, No. 12, May 1970. *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3913524A (en) * 1972-03-13 1975-10-21 Rank Xerox Ltd Liquid developing apparatus for electrophotography
US3893417A (en) * 1974-01-17 1975-07-08 Eastman Kodak Co Apparatus for liquid development of electrostatic images
US5488466A (en) * 1994-08-08 1996-01-30 Xerox Corporation Liquid development system

Also Published As

Publication number Publication date
FR2072381A5 (enrdf_load_stackoverflow) 1971-09-24
DE2058244B2 (de) 1977-04-28
DE2058244A1 (de) 1971-06-09
GB1302846A (enrdf_load_stackoverflow) 1973-01-10
JPS4838261B1 (enrdf_load_stackoverflow) 1973-11-16
BE759353A (fr) 1971-04-30
CA923296A (en) 1973-03-27
NL7017291A (enrdf_load_stackoverflow) 1971-06-01

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