US3705767A - Electrophotographic device - Google Patents

Electrophotographic device Download PDF

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Publication number
US3705767A
US3705767A US56852A US3705767DA US3705767A US 3705767 A US3705767 A US 3705767A US 56852 A US56852 A US 56852A US 3705767D A US3705767D A US 3705767DA US 3705767 A US3705767 A US 3705767A
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United States
Prior art keywords
sensitive layer
color
image
processing units
roller
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Expired - Lifetime
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US56852A
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English (en)
Inventor
Yasuo Tamai
Osamu Fukushima
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Fujifilm Holdings Corp
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Fuji Photo Film Co Ltd
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Publication date
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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
    • G03G15/01—Apparatus for electrographic processes using a charge pattern for producing multicoloured copies
    • G03G15/0142—Structure of complete machines

Definitions

  • the interconnected processing units are moved across the surface of a stationary electrophotographic sensitive material on which the image of the colored original is projected, the original also being held in a stationary position whereby the colored original is reproduced on the surface of the sensitive material after all processing units are moved thereacross.
  • a color image can be obtained by repeating, for varying combination of filters and toners, the process consisting of the steps of exposing an electrically charged xerographic plate to a given image through a colordecomposing filter, developing the latent image with a toner possessed of a complementary color with reference to the color filter, and transferring the toner image onto a white paper.
  • an electrophotographic device whereby the positional relation between the original and the sensitive layer can be maintained unchanged during the process of color reproduction.
  • This device is also characterized by its capability of accomplishing the color reproduction in an extremely short period.
  • the exposure to image is accomplished while the processing unit consisting of a corona charging electrode, an optical filter, a liquid developing device, and squeeze rollers is passing over the surface of an immobilized sensitive layer.
  • the processing unit consisting of a corona charging electrode, an optical filter, a liquid developing device, and squeeze rollers is passing over the surface of an immobilized sensitive layer.
  • the exposure to image is accomplished continuously over the entire surface of a sensitive layer while a plurality of such processing units are passing thereover. Accordingly, absence of color registration cannot occur at all in the resultant image because the original, the optical lens system, and the sensitive layer remain stationary during color reproduction.
  • this device can be utilized for not only color reproduction but also monochrome reproduction. Therefore, the object of this invention resides in providing a novel electrophotographic device. Another important object of the invention consists in providing an eIectrophotographic device capable of rapidly accomplishing color reproduction. A still other object of this invention is to provide an electrophotographic device capable of producing color images without involving absence of color registration.
  • FIG. 1 and FIG. 2 are side elevations in longitudinal section of processing units to be used for the present invention
  • FIG. 3 and FIG. 4 are side elevations in longitudinal section of devices having a plurality of processing units interconnected so as to carry out color reproduction, and
  • FIG. 5 is a side elevation in longitudinal section of an electrophotographic device of the present invention.
  • FIG. 1 illustrates the condition in which the processing unit of the present invention is passing over the sensitive layer from right to left in the drawing.
  • a plurality of such processing units are interconnected and put to use.
  • the case 3 of the processing unit is made of metal plate, for example. It serves to enclose the processing unit only on its lateral sides.
  • the processing unit is moved from right to left for its service.
  • a vacant space Through this vacant space, therefor, rays of light conforming to the image projected from above the processing unit can reach the sensitive layer without being intercepted.
  • this vacant space 4 serves the purpose of eliminating electrostatic charge remaining on the surface of sensitive layer by virtue of light.
  • the corona charging member consisting of a shielding plate 6 and a corona discharge electrode 5 is positioned next to the space.
  • the surface of the sensitive layer 1 is electrically charged by having this member pass over the electrophotographic sensitive layer.
  • the corona discharge electrode 5 is illustrated as one composed of thin metallic wire. It goes without saying that what may be formed by placing needle-shaped electrodes side by side can be used as such.
  • This corona discharge electrode 5 is connected to a remote highvoltage power source.
  • the shielding plate 6 is made of metal and is grounded electrically. The distance between the corona discharge electrode 5 and the sensitive layer 1 is determined by the magnitude of the electric potential applied by the corona discharge electrode 5 and the speed at which the processing unit is moved.
  • the optical filter 7 Next to the corona charging member is disposed the optical filter 7. While the processing unit is moving over the sensitive layer 1, exposure to image is performed continuously from above the processing unit.
  • This roller 9 has a porous surface capable of easily absorbing and retaining a liquid and contains on the surface an electrophotographic light developing agent. While this roller 9 is held in contact with the surface of the sensitive layer, the tonerin the liquid developing agent contained in the roller 9 is caused to deposit on the surface of sensitive layer in conformity to the electrostatic latent image formed on the surface of sensitive layer. Thus is developed the latent image.
  • the surface of sensitive layer which has undergone the step of developing and consequently has been wetted with the liquid developing agent is then squeezed by the roller 10.
  • the roller 10 is made of an element having a smooth surface, such as a metallic roller possessed of a surface of mirror-face finish.
  • the liquid developing agent collects on the surface of sensitive layer which is positioned between the developing roller 9 and the squeeze roller 10. Such excess liquid developing agent is absorbed by the pad 11 which is capable of absorbing liquid. This pad 11 is held in intimate yet smooth contact with the squeeze roller 10. Thus, the surface of the squeeze roller 10 is kept clean at all times.
  • the liquid developing agent which has been absorbed by the liquid-absorbing, pad 11 is returned to the developing roller 9 as the amount of liquid developingagent within the developing roller 9 becomes small. This transfer of liquid developing agent occurs because the pad 11 and the developing roller 9 are held in light contact with each other.
  • Removal of the excess developing agent deposited on the surface of sensitive layer may be accomplished without necessarily resorting to such squeeze roller. It may be accomplished by blowing a current of air against the surface, for example.
  • the processing unit After the processing unit has passed over, there remains an image on the surface of sensitive layer as a result of development.
  • the upper section of the processing unit is optically shielded against light coming from above, except the vacant space 7 and the optical filter member. 7.
  • the shielding plate 12 is intended to provide such optical shielding.
  • the pipe 13 is intended to supply the insulative liquid to the roller 8.
  • the processing unit which has been explained by referring to the diagram of FIG. 1 above, is suitable for the development wherein the projection of light is made downwardly.
  • the processing unit is housed in the case 24 which is covered only on its lateral sides.
  • the processing unit is made to travel from right to left.
  • the vacant space 25 there are arranged the corona electrode 26, the shielding plate 27, and the optical filter 28 in sequence in the direction of travel as in the case'of the embodiment illustrated in FIG. 1.
  • the surface of the sensitive layer is electrically charged and then exposed to the color-decomposed image.
  • an insulative liquid is spread by the roller 29 similarly to the roller 8 of the former embodiment. Below the roller 29 is situated the reservoir 32 for the insulative liquid.
  • the insulative liquid is preserved within the container 33 and constantly keeps the roller 29 wet.
  • the development is made by the developing roller 30.
  • the developing roller may be similar to the developing roller 9 which was described in the embodiment of FIG. 1.
  • the roller 30 may be brought into direct contact with the surface of latent image on the sensitive layer.
  • the roller 30 may be a simple metallic roller. If there is provided a mechanism whereby the developing roller 30 is revolved with the travel of the processing unit, then the liquid developing agent 37 is taken up by the surface of the roller 30 and is then applied to the surface of sensitive layer. In case where the roller 30 is made of metal, it is not desirable for the roller 30 to achieve either linear contact or surface contact directly with the surface of the sensitive layer 21. Such contact has the possibility of destroying the electrostatic latent image.
  • the roller 30 is so adjusted that it will keep a fixed opening from the surface of sensitive layer.
  • the opening is suitable in the range of from 0.05 mm to 1 mm.
  • the lower limit depends on the smoothness of the surface of the sensitive layer and the mechanical precision of the mechanism in question, while the upper limit is determined by the viscosity of the liquid developing agent.
  • the so-called toner sheet process by having a porous roller.
  • the roller may be held in contact with the sensitive layer.
  • Numeral 3,8 denotes the container for holding the liquid developing agent.
  • the surface containing the developed image is squeezed by the squeeze roller 31.
  • the excess developing agent which has been squeezed out falls back into the container 38. After the processing unit has travelled from right to left, there is left on the surface of the sensitive layer an image which has undergone the treatment of development.
  • the shielding plate 27, the container 33, and the container 38 are made of materials impervious to light. This is for the purpose of shielding the processing unit against the passage of light coming from below, with the exception of the filter 28 and the vacant space 25.
  • the vacant spaces 4 and 25 respectively are intended to eliminate, by virtue of light, the electrostatic charge remaining on the surface of the sensitive layer. Therefore, a lamp may be placed in such space to project light for the same purpose. Otherwise, an AC corona discharge electrode may be disposed to accomplish this purpose.
  • FIG. 3 illustrates the condition in which the development is made by using three processing units of FIG. 1 interconnected with one another.
  • the interconnected unit moves from right to left with reference to the drawing.
  • projection of light is made downward.
  • the exposure to light is carried out continuously while the interconnected processing unit passes over the electrophotographic paper 35 which is fixed immovably on the supporting board 36.
  • exposure to light begins at the moment that the optical filter 43 of the first processing unit arrives at the right edge of the sensitive paper 35 and continues until the optical filter 51 of the third processing unit has passed the left edge of the sensitive paper 35.
  • Such continuous exposure to light characterizes the present invention.
  • the optical filter for color decomposition is incorporated in the processing unit, there is no need for inserting any optical filter in the optical system for image projection (near the lens or in front of the original, for example). Consequently, the original is illuminated by a light source of white color so that the image which is not color-decomposed in any way is projected through the lens system onto the processing unit, with the focus adjustcd to the surface of the electrophotographic sensitive layer.
  • the aforementioned projection of color image is started.
  • the vacant space portion 41 is shielded against passage of light.
  • the sensitive layer is electrically charged by the corona charge element 42.
  • the first unit is used for developing an image in magenta color
  • the unit in the middle for developing an image in cyan color
  • the last unit for developing an image in yellow color respectively.
  • the optical filter 43 to be used in the magenta color developing unit should be in green color.
  • the electric charge remaining on the surface is eliminated by the light from the image which passes through the vacant space 47 of the unit in the middle.
  • the light which passes the vacant space 47 originates from the projection of the original image. Ifthis is the light from the color image, the light of image including the magenta color constituent penetrates through the toner image of magenta color and reaches the surface of sensitive layer. Consequently, the electric charge remaining in the surface of sensitive layer beneath the image of magenta toner is eliminated. If the image of the original happens to be in black color, the electric charge below the image of magenta toner is not eliminated. This has no adverse effect whatever on this invention. The reason is that, where the image of original is in black color, the second and third toners are required to deposit on top.
  • the portion which has acquired the image of magenta toner by means of the first unit is immediately charged electrically by the corona charge element 48 of the second processing tuiit and then exposed to light through the optical filter 49.
  • This optical filter 49 is in red color.
  • the data on the cyan color of the original are formed on the surface of sensitive layer as a static latent image.
  • This latent image is developed by the developing roller 50.
  • This developing roller 50 contains a liquid developing agent which incorporates therein a toner of cyan color.
  • the area which has remained undischarged by the light passed through the red filter 49 is developed in cyan color.
  • the optical filter 51 is in blue color and the developing roller 52 contain a liquid developing agent incorporating therein a toner of yellow color. Also in this case, development is made by the same mechanism, with a yellow image formed on top on the surface of sensitive layer. The projection of light is discontinued the moment that the optical filter Sl has passed the entire surface of the sensitive layer. The reproduction of color image is accomplished by having the interconnected processing unit pass over the surface of sensitive layer while the projection of image is in continuation.
  • FIG. 4 denotes a supporting board, 61 an electrophotographic sensitive layer fixed on the supporting board with the surface of sensitive layer looking downwardly, and 63 a light-shielding screen. The image is projected continuously upwardly to the entire surface of the sensitive layer.
  • the interconnected processing unit is disposed in much the same way as shown in'FIG. 3.
  • the first unit consists of the optically closed vacant space 64, corona discharge element 65, green filter 66, roller '67 for applying the insulative liquid, liquid developing agent 68 containing a toner of magenta color, developing roller 69, and squeeze roller 70.
  • the unit in the middle has vacant space 71, corona charging element 72, red filter 73, and others, with the liquid developing agent 74 incorporating a toner of cyan color.
  • the filter 75 is in blue color
  • the liquid developing agent 76 contains a toner of yellow color.
  • this unit is similar to the other units.
  • the interconnected processing unit is mounted on guard rails (not shown) which are laid on both lateral sides exterior to the sensitive paper section as seen in the direction of travel. It is made to travel along the surface of the sensitive layer.
  • the electrophotographic sensitive paper to be used in the device of the present invention is desired to have sensitivity to light of the entire visiblezone.
  • the decomposing sensitivity in the visible zone is not uniform, it is desirable to control the position of the corona electrode disposed inside each processing unit (with reference to the distance from the sensitive layer) or the width of filter as measured in the direction of travel. By such control, the optical density of each color image can be uniformalized with ease.
  • the sensitive paper suffers from low sensitivity, an image of good quality can readily be obtained by suitably lowering the speed at which the unit passes over the paper. In case where the speed of the travel is lowered, it is desirable to either lower the electric potential to be applied to the corona electrode or prevent overcharge by increasing the distance of the corona electrode from the surface of sensitive layer.
  • the processing unit can be made to travel at an increased rate. There is a possibility that excessively high speed of travel may fail to provide sufficient development. In such case, the speed of travel can be lowered by-decreasing the width of filter. Where there is shortage of electric charging, the corona electrode has only to be brought closer to the surface of sensitive layer.
  • the adjustment of color balance can be accomplished by increasing or decreasing the distance between the corona electrode and the sensitive layer and the length of the filter.
  • FIG. 5 One example of the electrophotographic device according to the present invention is shown in FIG. 5.
  • the sensitive paper is rolled up and preserved in that state.
  • the reproduction of color image is accomplished by using the interconnected combination 88 of three developing units.
  • processing units are interconnected as shown in FIG. 4 and used in that state. In the device of FIG. 5, however, the processing unit is made to travel from left to right with reference to the drawing.
  • the sensitive paper 85 is laid out and fixed in the focal plane of the optical system onto the pressing plate 86.
  • this pressing plate 86 may be a simple plate, it is desired to have such mechanism that air is sucked from behind through holes or grooves provided thereon, whereby the sensitive paper will be held fast against the plate.
  • the original containing a color image which is to be reproduced is held under pressure against a transparent glass 92.
  • the original is illuminated by the light source 95 while the interconnected processing unit 88 passes over the sensitive paper. Strictly speaking, it is desirable that the illumination starts a little before the passage of the interconnected processing unit 88 over the sensitive paper. This is because the color temperature is required to be stabilized after the temperature of light source has risen sufficiently.
  • the shutter 97 is opened after the illumination is started but before the interconnected processing unit 88begins to travel.
  • the image projected through the lens system 93 is formed via the mirror 94 onto the surface of sensitive layer.
  • the light-shielding screen 96 At the front end of the processing unit, there is disposed the light-shielding screen 96.This serves the purpose of obstructing the passage of light before the processing unit 88 reaches the surface of sensitive paper. Where the sensitive paper to be used has such electric charging property that it will hardly experience exhaustion due to pre-exposure, this light-shielding screen 96 is not necessarily required.
  • the front end of this lightshielding screen 96 is pulled by a chain or a wire 90. As the processing unit crosses the front surface of the sensitive paper and travels at an equal speed, the wire and the light-shielding screen 96 are wound up on the shaft 91. When the interconnected processing unit 88 has passed the front surface of sensitive paper, the shutter 97 is closed and the light source is extinguished.
  • the pressing plate which holds the sensitive paper fast goes up and the sensitive paper which now carries a color image is forwarded to the right with reference to the drawing to be cut by the sheeter (cutter) 87 and discharged in the shape of a sheet.
  • the processing unit 88 which has been moved to the right in the drawing after the step of developing is returned to its original position (left in the drawing) by virtue of the wire. This is done because the wire connected to the shaft 91 is wound up. As a matter of course, the mechanism which has caused the wire 90 and the light-shielding screen 96 to be wound up on the shaft 91 is released at this point.
  • the processing unit 88 During the return travel of the processing unit 88, none of the rollers incorporated in the processing unit 88 is allowed to come into contact with the surface of sensitive paper. For this purpose, the pressing plate may go up while holding the sensitive paper thereon or the processing unit may return to its original position while in a slightly loweredstate.
  • the tanks 81, 82, 83, and 84 are used for holding liquid developing agents of different colors and the insulative liquid. When liquids held in the processing unit 88 are running short, corresponding liquids are supplied from these tanks via pipes (not shown in the drawing) into the interconnected processing unit 88.
  • the corona discharge electrode provided in each processing unit is connected to the DC highwoltage power source 98 provided within the device by means of a long flexible high-voltage cable. High voltage is applied to the corona discharge electrode only'while the processing unit 88 is traveling over the front surface of sensitive paper.
  • the present invention accomplishes color reproduction with extreme ease by causing the interconnected processing unit possessed of a special mechanism as mentioned above to travel over the electrophotographic sensitive paper which is continuously exposed to light projected through a given image. While reproduction is in progress, the positional relation among the original, the optical lens system, and the sensitive paper remains perfectly unchanged. Therefore, the so-called absence of color registration cannot be observed at all in the resultant color image. It is also a conspicuous characteristic that a color copy can be obtained in a decidedly shorter time than is required by the conventional color reproducing method without the aid of human hand.
  • the present invention can sufficiently satisfy the mounting demand for faithful reproduction of an original containing a color image prevailing in the market and therefore proves to be extremely important industrially.
  • An electrophotographic device for reproducing a colored original comprising:
  • each color-decomposing filter means disposed approximately adjacent to and farther from said one end than said charging means, each color-decomposing filter means corresponding to a unique color constituent of said colored original;
  • developing means disposed approximately adjacent to and farther from said one end than said color decomposing filter means for developing latent images on said sensitive layer with a toner of a color complementary to the color of said color-decomposingfilter means
  • each said processing unit includes an opening extending vertically therethrough disposed between said one end and said charging means so that the light of said colored original image may substantially discharge any electrostatic charge on said sensitive layer.
  • liquid developer contacting means includes a roller having a porous portion containing said liquid developer, said roller being held in contact with said sensitive layer so that said latent image is developed by the toner carried in said held in contact with said sensitive layer to squeeze said excess liquid developer off of said sensitive layer.
  • a device as in claim 1 including an opaque member disposed outside of and adjacent to said one end of the first of said processing units for preventing the illumination of said sensitive layer by said image of the colored original, said opaque member being connected in series with said processing units and moved by said moving means so that said sensitive member is not exposed to said image of the colored original until said processing units are moved thereacross.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Color Electrophotography (AREA)
  • Wet Developing In Electrophotography (AREA)
US56852A 1969-07-21 1970-07-21 Electrophotographic device Expired - Lifetime US3705767A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP44057544A JPS4811054B1 (fr) 1969-07-21 1969-07-21

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US3705767A true US3705767A (en) 1972-12-12

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US56852A Expired - Lifetime US3705767A (en) 1969-07-21 1970-07-21 Electrophotographic device

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US (1) US3705767A (fr)
JP (1) JPS4811054B1 (fr)
BE (1) BE753687A (fr)
CA (1) CA947357A (fr)
DE (1) DE2036140C3 (fr)
FR (1) FR2055388A5 (fr)
GB (1) GB1266112A (fr)
NL (1) NL7010560A (fr)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3838920A (en) * 1972-04-21 1974-10-01 Hitachi Ltd Electrophotographic copying apparatus
US3900003A (en) * 1973-06-15 1975-08-19 Canon Kk Liquid developing device for electrophotography
US3910231A (en) * 1973-02-21 1975-10-07 Canon Kk Developing device for a polychromatic electrophotographic copier
US3923004A (en) * 1973-12-27 1975-12-02 Xerox Corp Development and cleaning apparatus for reverse path machine
US3970042A (en) * 1975-01-17 1976-07-20 Xerox Corporation Color development apparatus
US4106870A (en) * 1973-12-28 1978-08-15 Canon Kabushiki Kaisha Color electrophotographic method and apparatus
GB2205657A (en) * 1987-06-09 1988-12-14 Brother Ind Ltd Image recording apparatus provided with exposure unit using cathode ray tube
US4827869A (en) * 1986-09-30 1989-05-09 Kabushiki Kaisha Toshiba Single and multi-color developing apparatus

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1436631A (en) * 1972-04-12 1976-05-19 Hitachi Ltd Electrophotographic colour copying apparatus
JPS4915732A (fr) * 1972-05-31 1974-02-12
JPS50131368U (fr) * 1974-03-29 1975-10-28
DE2421661C2 (de) * 1974-05-04 1982-05-13 Agfa-Gevaert Ag, 5090 Leverkusen Elektrostatisches Kopiergerät
DE3008479A1 (de) * 1980-03-05 1981-09-17 Agfa-Gevaert Ag, 5090 Leverkusen Verfahren und vorrichtung zur elektrophotographischen herstellung von farb-halbtonkopien
US4358195A (en) * 1980-04-11 1982-11-09 Coulter Systems Corporation Electrophotographic color proofing apparatus
JPS59162580A (ja) * 1983-03-08 1984-09-13 Fuji Photo Film Co Ltd 電子写真装置用プロセスヘツド
DE3483877D1 (de) * 1983-10-03 1991-02-07 Konishiroku Photo Ind Mi-vielfach-bild-reproduktionsverfahren.

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3305459A (en) * 1963-08-27 1967-02-21 Minnesota Mining & Mfg Electrolytic electrocopying method and apparatus
US3467468A (en) * 1967-03-30 1969-09-16 Rca Corp Automatic color electrophotographic apparatus

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3305459A (en) * 1963-08-27 1967-02-21 Minnesota Mining & Mfg Electrolytic electrocopying method and apparatus
US3467468A (en) * 1967-03-30 1969-09-16 Rca Corp Automatic color electrophotographic apparatus

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3838920A (en) * 1972-04-21 1974-10-01 Hitachi Ltd Electrophotographic copying apparatus
US3910231A (en) * 1973-02-21 1975-10-07 Canon Kk Developing device for a polychromatic electrophotographic copier
US3900003A (en) * 1973-06-15 1975-08-19 Canon Kk Liquid developing device for electrophotography
US3923004A (en) * 1973-12-27 1975-12-02 Xerox Corp Development and cleaning apparatus for reverse path machine
US4106870A (en) * 1973-12-28 1978-08-15 Canon Kabushiki Kaisha Color electrophotographic method and apparatus
US3970042A (en) * 1975-01-17 1976-07-20 Xerox Corporation Color development apparatus
US4827869A (en) * 1986-09-30 1989-05-09 Kabushiki Kaisha Toshiba Single and multi-color developing apparatus
GB2205657A (en) * 1987-06-09 1988-12-14 Brother Ind Ltd Image recording apparatus provided with exposure unit using cathode ray tube
US4931825A (en) * 1987-06-09 1990-06-05 Brother Kogyo Kabushiki Kaisha Image recording apparatus provided with exposure unit using cathode ray tube
GB2205657B (en) * 1987-06-09 1991-05-01 Brother Ind Ltd Exposure unit using cathode ray tube

Also Published As

Publication number Publication date
CA947357A (en) 1974-05-14
NL7010560A (fr) 1971-01-25
BE753687A (fr) 1970-12-31
JPS4811054B1 (fr) 1973-04-10
DE2036140C3 (de) 1974-05-16
DE2036140A1 (de) 1971-02-04
GB1266112A (fr) 1972-03-08
DE2036140B2 (de) 1973-10-18
FR2055388A5 (fr) 1971-05-07

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