US3771866A - Transfer type electrophotographic duplicating apparatus - Google Patents

Transfer type electrophotographic duplicating apparatus Download PDF

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Publication number
US3771866A
US3771866A US00212916A US3771866DA US3771866A US 3771866 A US3771866 A US 3771866A US 00212916 A US00212916 A US 00212916A US 3771866D A US3771866D A US 3771866DA US 3771866 A US3771866 A US 3771866A
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Prior art keywords
roller
transfer
film
sensitive film
driving
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Expired - Lifetime
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US00212916A
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English (en)
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M Ogawa
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Minolta Co Ltd
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Minolta Co Ltd
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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
    • G03G15/22—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20
    • G03G15/28—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 in which projection is obtained by line scanning
    • G03G15/283—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 in which projection is obtained by line scanning using a reusable recording medium in form of a band

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  • This invention relates to a transfer type electrophotographic duplicator in which an original picture and a sensitive material are stationary and an exposure optical system moves therebetween to project in turn original picture images.
  • Transfer type duplicators in the prior art are in genera] of the dry toner figure-transfer type represented by the Carlson system duplicator.
  • a drum-shaped sensitive material is used and the picture image exposure is effected by running an exposure optical system in connection with the circumferential speed of the drum-shaped sensitive materiaL- It is hard to obtain a copy of clear picture quality and the mechanism is complex because of the two moving members therof.
  • the duplicator itself is of a very large-size and as a result it must be manufactured into a console form.
  • copying paper is used as the sensitive material, so that the paper isthick and accordingly the copying paper is heavy.
  • One object of the present invention is to provide a transfer type electrophotographic duplicator in which the sensitive material is planar, and an original picture and the sensitive materialare stationary and an exposure optical system is moved to effect exposure and projection. Accordingly dead spaces are reduced and yet a clear picture quality can be obtained.
  • Another object of the present invention is to provide a transfer type electrophotographic duplicator in which by moving the optical members as described above the whole mechanism is simplified and the duplicator itself is small-sized to fit on top of a desk.
  • Another object of the present invention is to provide a transfer type electrophotographic duplicator capable of developing either by wet or dry techniques.
  • Still another object of the present invention is to provide a transfer type electrophotographic duplicator using a flexible sensitive material quite different in construction and the method of exposure from those in the prior duplicators, and which is very flexible and has reliable sensitive material.
  • FIG. 1 is an illustration of the construction and the image forming principle of a sensitive material used in the transfer type electrophotographic duplicator inaccordance with the present invention.
  • FIG. 2 is a side view showing an outline of an electrostatic latent image forming portion of a duplicator in accordance with the present invention.
  • FIG. 3 is a side view showing an outline of one embodiment in accordance with the present invention.
  • FIG. 4 is a detailed view of the essential portion of a carrying roller for the sensitive material of the embodiment of FIG. 3.
  • FIG. 5 is a diagram of an electric circuit for the embodiment of FIG. 3.
  • FIG. 6 is a time chart for illustrating the time function of the essential portion of the embodiment of FIG. 3.
  • FIG. 7 is a side view showing an outline of another embodiment of a duplicator in accordance with the present invention.
  • FIGS. 8A and 8B are respectively sectional views of the developing portion of the embodiment of FIG. 7, wherein FIG. 8A shows the components at the developing time and FIG. 8B shows the components at the nondeveloping time. I
  • FIG. 9 is a perspective view showing one example of a developing device of the embodiment of FIG. 7.
  • FIG. 10 is a diagram of an electric circuit for the embodiment of FIG. 7.
  • FIG. 11 is an illustration of the time function of the essential portion of the embodiment of FIG. 7.
  • FIG. 1 the construction and the image forming principle of a sensitive material used in a duplicator in accordance with the present invention are illustrated.
  • FIG. 1 shows one embodiment of a sensitive material P so formed that for example, onto flexible transparent support a made of a polyester film of ,1.
  • thickness, thin film b made of a conductive material of less than 1 ,4. thickness is evaporated, and thereon there is formed a thin film s (can contain Te in less than 7 percent by weight ratio) formed by evaporating a photosemiconductor such as non-crystalline Se of l p. or so thickness.
  • a flexible high resistance organic semiconductive file d formed by applying an organic semiconductor from 10 to 15 p. dry film thickness containing polyvinylcarbazole using diphenylthiocarbazone trickloride as a plasticizer and monochlorobenzene as a solvent.
  • the polyvinylcarbazole can contain a very little silicone as the characteristic of electrophotographic image forming is not affected and in'this case diphenylthiocarbazone trichloride is not used.
  • Se thin film 0 is photo-excited by light passing through b thin film b and positive holes generated thereby flow to the organic photosemiconductor d side by the negative electric charge on the surface, pass through organic photosemiconductor film d and move to the. surface as shown in the drawing to neutralize the negative electric charge on the surface.
  • thin film .Se formsahigh rectification barrier at the interface of Se thin film c to prevent positive holes from moving to Se thin film c, and thereby an. electrostatic latent image having improved picture image concentration and contrast is formed.
  • a sensitive film practical as a transfer type sensitive, material is obtained, wherein thin film b and Se thin film c are less than 1 p. or so in thickness,
  • PVK film d and polyster film a are made of macromolecule material.
  • thin film b and Se evaporation film can be strongly adhered by exposing thin film b in a glow discharge to give a forced oxidation through ion bombardment and then vacuum evaporating the Se. Therefore, for example even though this sensitive material is formed into a belt-shape and put over two rollers of 30 mm to be rotated at a high speed such as 1 m/s for 1000 hours no exfoliation takes place between film b and Se film c, and it is possible to use the photosensitive material as a belt-shaped sensitive sheet or as a roll-shaped sensitive film.
  • the flexible sensitive film is'formed by layering in order onto flexible transparent support a, thin film b made of a conductive material which is an electrode of very thin thickness and having a transmission factor above 50 percent, and contacts with photosemiconductive film c to form a high rectifying barrier for preventing electric charge from migrating into film c.
  • a very thin organic photosemiconductive film c the whole of which absorbs light to generate electric charge carriers, and a flexible high resistance semiconductor film d functioning as a passage for the electric charge carriers generated by photosemiconductive film c are also deposited.
  • the flexible sensitive film is quite different in construction, the mechanism for sensitizing, and in the image exposure direction from sensitive film or sensitive papers used in the prior art duplicators.
  • the sensitive film is strong, has good flexibility, and is able to charge to a high potential of IOOOV or more and effect picture image exposure to a high sensitivityas from to 30 Lux-Sec. Additionally, it has very little preexposure effect, and thus it is possible to form an electrostatic latent image of high contrast and high resolving power.
  • FIG. 2 shows the construction of the original picture image forming portion of the duplicator in accordance with the present invention, making use of sensitive film P in which the flexible sensitive film is formed into a roll-shape.
  • sensitive film P in which the flexible sensitive film is formed into a roll-shape.
  • FIG. 2 relative to stationary original picture 0 sensitive film P is disposed with flexible high resistance semiconductor film d facing down and both ends thereof are respectively wound around rolls 1 and 2.
  • Rolls 1 and 2 are energized respectively in the direction to take up the film weakly by a spring means not shown in the drawing, and film P is evenly disposed by two rollers 3 for keeping it in a plane and carried by carrying roller 4.
  • original picturelength exposure means B constituting erect optical system L having, for example, irradiation lamp I with a reflecting shape, one mirror lens, and two reflecting mirrors in a body and providing a slit; and on the down side of sensitive film P there is disposed stationary corona discharge device A for uniformly charging flexible high resistance semiconductive film d.
  • slit exposure means B is moved in the direction shown by the arrow and thereby the picture image of original picture 0 irradiated by irradiation light source I is projected on transparent support film a on the back side of sensitive film P through erect optical system L.
  • An electrostatic latent image corresponding to original picture 0 is formed on the surface of sensitive film P.
  • sensitive film P is carried into position for effecting transfer.
  • the whole mechanism thereof is very simple and in addition the following advantages are gained: as compared with the prior art transfer type duplicator the duplicator itself can be small-sized and used as a-desk type, and when an image is formed the original picture and the sensitive body are both stationary, so that a copy of clear picture quality can ge expected.
  • FIG. 3 shows an electrostatic latent image type duplicating apparatus, wherein parts corresponding to the parts shown in FIG. 2 are designated the same.
  • original glass base plate 6 on the top of duplicator case body 5 original glass base plate 6 is provided and exposure means B is provided so as to move parallel to glass base 6 by means of guide rail 8 through roller 7 provided rotatably on the side of exposure means B cable 10 both ends of which are fastened respectively to two pins 9 provided on the side of exposure means B are wound over pulley 11 for driving motor MB and driven pulley l2.
  • exposure means B can be moved in the direction shown by the arrow through rotation of motor MB, and when return switch SWR is switched off motor MB is stopped and at the same time exposure means B is returned to the original position by return spring 13 provided between the left side wall of the duplicator case body and exposure means B.
  • Carrying roller 4 is provided to rotate in either direction using driving motor MP as a driving source and also to turn cam 14 as shown in FIG. 4.
  • driving motor MP as a driving source
  • cam 14 On the circumference of can 14 there are disposed micro-switches SWAl, SWA2, and SWA3 which'are respectively actuated by projection 14a of cam 14.
  • Driven roller 4' is composed of a grounded conductive member, and in the embodiment, for both rollers 4 and 4' a conductive rubber roller is used to constitute latent image transfer portion K.
  • Transfer paper T piled on transfer paper base 15 is formed by applying onto a paper of p. or so thickness a conductive treatment to a high dielectric material such as polyethylene, wax, alkyd resin, cellulose acetate, epoxide. Further a resin film such as vinyl chloride vinyl acetate copolymer up to 2 to 10 1. thickness is also formed thereon, and delivered singly by feed roller 16 driven by motor MT.
  • the delivery time is set so as to be controlled in accordance with the movement of sensitive film P, and the electrostatic latent image forming portion on sensitive film P and the tip of transfer paper T are controlled to be carried concurrently to the clearance between both rollers 4 and 4'.
  • Liquid developing device D mounted in the after position of the transfer mechanism is provided with well known, for example, a pair of delivery rollers 17, guide plate and concurrently developer saucer 18, electrode 19, developer tank 20, developer supply means for supplying the developer in tank 20 to saucer 18 which passes through pipe 22 by means of pump 21 driven by motor MD shown in FIG. 5. Excess developer is returned to tank 20 from the side of saucer 18, and a pair of throttle rollers 23 are also provided.
  • dry fixing device F composed of heater H and a blower driven by motor MD, and under it'conveyor belt 25 is disposed for carrying transfer paper T while drying it to copy receiving plate 24 provided on the side plate of duplicator case body 5.
  • delivery rollers 17, throttle rollers 23, and conveyor belt 25 are-driven by motor MR through a well known transmission means not shown in the draw- Reference numeral 26 denotes a light intercepting screen spread between side plates of exposure means B and case body 5.
  • the electric circuit of the duplicator is connected as shown in FIG. 5, and main switch SM and start switch SS are provided in a position accessible to be manipulated from the outside.
  • sensitive film P is carried while flexible high resistance semiconductive film d is charged by corona discharge device A and when semiconductive film d is carried a predetermined length projection 14a of cam 14 operates microswitch SWB, so that relay RY2 is excited, all contacts from 18 to 48 thereof are respectively switched-over to contact b, relay RY2 is selfheld through contact 18, and thereby contact 2B stops the rotation of motor MP and relay contact piece 4B cuts off high tension transformer CH to stop the discharging of corona discharge device A. Simultaneously therewith, light source I is lit through contact 33, motor MB is started, and exposure means B is moved in the direction shown by the arrow to project the picture image of .original picture 0 in turn onto the back side of sensitive film P. Thus an electrostatic latent image of the mirror image corresponding to the original picture is formed on flexible high resistance semiconductive film d on the surface of the sensitive film.
  • Sensitive film P and transfer paper T are interposed between carrying roller 4 and driven roller 4 so that they come into close contact with each other, and the electrostatic latent image on sensitive film P is transferred in turn onto transfer paper T.
  • cam 14 After transfer, cam 14 is returned to its original position and projection 14a operates microswitches SWAl and SWA2, and when both switches SWAl and SWA2 are switched-over to contact b the rotation of motor MP is stopped, carrying roller 4 is stopped, and sensitive film P is returned to its original position.
  • transfer paper T on which the electrostatic latent image is transferred is carried to liquid developing device D by roller 17 and toner is applied to the latent image between saucer 18 and electrode 19 to develop it, and then transfer paper T is carried onto conveyor belt 25 while excess developer is removed by throttle rollers 23. The transfer paper is then carried to copy receiving plate 24 while it is dried and fixed on the belt by the dry fixing device F.
  • a latent image transfer type duplicator As described above, by forming a latent image transfer type duplicator, as compared with the prior art transfer type duplicators such as a drum sensitive body type, a picture image of very high quality can be made, a sensitive body film can be used effectively. Further exchanging of the films is very simple, and in addition the sensitive body film can be reciprocated in one plane, so that dead space is minimized and a desk type duplicator nearly the same size as prior electrofax type duplicators can be obtained. Also the copy obtained is of high quality by virtue of the ultrafine grain characteristic of a liquid developer.
  • FIG. 7 shows an embodiment of a dry toner transfer type wherein the parts corresponding to those in FIG. 3 are denoted by the same designations.
  • transfer paper T can be conventional paper such as is used in a xerography type duplicator, and a dry type developer is used.
  • rotary roller 27 and opposite polarity plate 28 constitute the developing portion and for sensitive film P a magnetic material is used. Between both ends thereof permanent magnets 29 are disposed to magnetize rotary roller 27 and opposite plate 28 to different polarities so as to generate a magnetic flux.
  • a dry developing device D' is used which is so formed that developer 30 composed of magnetic carriers produced by the magnetic flux and toner is stored in developer tank 31, and for controlling the magnetic brush, relative to rotary roller 27 angled permanent magnetic piece 32 is provided on the outside of developertank 31 to rotate 90 degrees by means of solenoid R which is rotated 90 degrees and provided with return spiral spring 33.
  • FIG. 8A shows the state in which the magnetic brush is formed by permanent magnetic piece 32 and sensitive film P is being developed
  • FIG. 8B shows the state in which the formation of the magnetic brush is stopped.
  • Developing device D is disposed between corona discharge device A and transfer corona discharge device C opposite carrying roller 4.
  • roll 1 is positioned a little higher than carrying roller 4 so that sensitive film P may separate of itself from transfer paper T, and onto the sensitive film P cleaner 35 is applied.
  • corona discharge device A is provided in a body with exposure means B as described above and for a fixing device thermal fixing device F' provided with heater H is used.
  • transfer corona discharge device C delivery roller 36 for transfer paper T is provided, which isconnected to carrying roller 4 to be driven by any well known means.
  • corona discharge device A operates simultaneously with light source I, the developing and the transfer mechanisms are operated when roller 4 is reversely rotated, and the other mechanisms operate in the same manner as in the latent image type.
  • micro-switch SWB is operated by the cam, so that on sensitive film P uniform charging and image exposure are effected only for the moving distance of exposure means B and an electrostatic latent image is formed.
  • sensitive film P is carried to the roll 1 side through the inverse rotation of carrying roller 4, simultaneously with the feeding of transfer paper T rotary solenoid R is electrified to rotate degrees against the energy of spring 33.
  • magnet 32 is rotated so as to of a different polarity from rotary roller 27, and thereby a magnetic brush is produced between magnet 32 and rotary roller 37, therefore, between opposite plate 28 and rotary roller 27 the magnetic brush of the developer is'enhanced to develop the electrostatic latent image on the sensitive film.
  • the tip of transfer paper T trips microsw itch MSl located just before delivery roller 36 to operate transfer corona discharge device C and the paper passes by corona discharge device C while being in close contact with the film face developed by delivery roller 36.
  • the dry toner figure is transferred from the sensitive film face to transfer paper T and transfer paper T is automatically separated from the sensitive film face by its tension and dead load when sensitive film P changes its direction and guided to conveyor belt 25 and carried to saucer 24 while being fixed by thermal fixing device F. Then, sensitive film P is cleaned of the remaining toner by cleaner 35 before being taken up by roll 1.
  • driving motor MD for developing device D' can be connected to feed motor MT so as to be operated simultaneously therewith as shown by the one point chain line in FIG. 10.
  • the time function of the respective essential components is shown in FIG. 11.
  • a transfer type electrophotographic duplicator comprising:
  • exposure means including a light source for illuminating said original document, an optical system for projecting the positive image of said original and a slit for transmitting the projected image movable between the ends of said transparent plate in parallel therewith;
  • a supply roller and take-up roller for winding respective opposite ends of said flexible sensitive film and rotatably pivoted at respective positions on opposite sides of said exposure means for supporting said flexible sensitive film parallel to said transparent plate;
  • a driving roller for transferring said flexible sensitive film between said supply roller and said take-up roller
  • first switching means for stopping the rotation of said driving roller when said driving roller transfers said flexible sensitive film a distance a length longer than that of said original image
  • third switching means for actuating said driving roller to transfer the flexible sensitive film from said take 30 up roller to said supply roller with the operation of said second switching means;

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Combination Of More Than One Step In Electrophotography (AREA)
  • Electrophotography Using Other Than Carlson'S Method (AREA)
US00212916A 1970-12-30 1971-12-28 Transfer type electrophotographic duplicating apparatus Expired - Lifetime US3771866A (en)

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Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3970383A (en) * 1973-11-15 1976-07-20 Ricoh Co., Ltd. Apparatus for color electrophotography
US3985435A (en) * 1972-12-29 1976-10-12 Ricoh Co., Ltd. Color electrophotographic apparatus
US4001014A (en) * 1973-09-17 1977-01-04 Matsushita Electric Industrial Co., Ltd. Electrophotographic photosensitive plate having tellurium present in varying concentrations across its thickness
US4026703A (en) * 1974-03-29 1977-05-31 Matsushita Electric Industrial Co., Ltd. Dual-layered photoreceptor use in electrophotography
US4026647A (en) * 1972-09-01 1977-05-31 Ricoh Co., Ltd. Copy sheet feed device
US4046565A (en) * 1975-03-25 1977-09-06 Addressograph Multigraph Corporation Amorphous selenium coating
US4074217A (en) * 1975-05-21 1978-02-14 Ricoh Company, Ltd. Cleaning unit for an optical system in a copying machine
US4589759A (en) * 1984-08-31 1986-05-20 Xerox Corporation Reproducing apparatus with optic scanning module
US4610526A (en) * 1980-03-03 1986-09-09 Xerox Corporation Reproducing machine
US4801969A (en) * 1987-10-15 1989-01-31 Eastman Kodak Company Self-coiling exposure shade
US4982237A (en) * 1989-02-21 1991-01-01 Xerox Corporation Photoelectrophoretic printing machine

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3254998A (en) * 1962-04-02 1966-06-07 Xerox Corp Induction image formation
US3497297A (en) * 1967-09-06 1970-02-24 Eastman Kodak Co Segmented platen for electrostatic printing
US3499709A (en) * 1966-12-05 1970-03-10 Varian Associates Electrophotographic strip film devices with means for holding the film away from the photoconductor during film transport
US3510217A (en) * 1966-12-05 1970-05-05 Varian Associates Electrophotographic apparatus employing an elastic pressure pad for pressing the film against the photoconductor
US3551146A (en) * 1965-06-28 1970-12-29 Xerox Corp Induction imaging system
US3598579A (en) * 1967-09-06 1971-08-10 Eastman Kodak Co Method of transferring electrostatic images to a dielectric sheet wherein a reversal of potential is used to clear background areas
US3630608A (en) * 1968-11-14 1971-12-28 Pitney Bowes Sage Inc High-speed copier

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3254998A (en) * 1962-04-02 1966-06-07 Xerox Corp Induction image formation
US3551146A (en) * 1965-06-28 1970-12-29 Xerox Corp Induction imaging system
US3499709A (en) * 1966-12-05 1970-03-10 Varian Associates Electrophotographic strip film devices with means for holding the film away from the photoconductor during film transport
US3510217A (en) * 1966-12-05 1970-05-05 Varian Associates Electrophotographic apparatus employing an elastic pressure pad for pressing the film against the photoconductor
US3497297A (en) * 1967-09-06 1970-02-24 Eastman Kodak Co Segmented platen for electrostatic printing
US3598579A (en) * 1967-09-06 1971-08-10 Eastman Kodak Co Method of transferring electrostatic images to a dielectric sheet wherein a reversal of potential is used to clear background areas
US3630608A (en) * 1968-11-14 1971-12-28 Pitney Bowes Sage Inc High-speed copier

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4026647A (en) * 1972-09-01 1977-05-31 Ricoh Co., Ltd. Copy sheet feed device
US3985435A (en) * 1972-12-29 1976-10-12 Ricoh Co., Ltd. Color electrophotographic apparatus
US4001014A (en) * 1973-09-17 1977-01-04 Matsushita Electric Industrial Co., Ltd. Electrophotographic photosensitive plate having tellurium present in varying concentrations across its thickness
US3970383A (en) * 1973-11-15 1976-07-20 Ricoh Co., Ltd. Apparatus for color electrophotography
US4026703A (en) * 1974-03-29 1977-05-31 Matsushita Electric Industrial Co., Ltd. Dual-layered photoreceptor use in electrophotography
US4046565A (en) * 1975-03-25 1977-09-06 Addressograph Multigraph Corporation Amorphous selenium coating
US4074217A (en) * 1975-05-21 1978-02-14 Ricoh Company, Ltd. Cleaning unit for an optical system in a copying machine
US4610526A (en) * 1980-03-03 1986-09-09 Xerox Corporation Reproducing machine
US4589759A (en) * 1984-08-31 1986-05-20 Xerox Corporation Reproducing apparatus with optic scanning module
US4801969A (en) * 1987-10-15 1989-01-31 Eastman Kodak Company Self-coiling exposure shade
US4982237A (en) * 1989-02-21 1991-01-01 Xerox Corporation Photoelectrophoretic printing machine

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