US3901696A - Electrode-shunting method of producing electrophotographic pictures and apparatus therefor - Google Patents

Electrode-shunting method of producing electrophotographic pictures and apparatus therefor Download PDF

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US3901696A
US3901696A US373823A US37382373A US3901696A US 3901696 A US3901696 A US 3901696A US 373823 A US373823 A US 373823A US 37382373 A US37382373 A US 37382373A US 3901696 A US3901696 A US 3901696A
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image
support
electrode
photoconductive layer
master
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US373823A
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Eugen Mohn
Hansjurg Hermann
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Turlabor AG
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Turlabor AG
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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
    • 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
    • G03G15/0147—Structure of complete machines using a single reusable electrographic recording member
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G17/00—Electrographic processes using patterns other than charge patterns, e.g. an electric conductivity pattern; Processes involving a migration, e.g. photoelectrophoresis, photoelectrosolography; Processes involving a selective transfer, e.g. electrophoto-adhesive processes; Apparatus essentially involving a single such process

Definitions

  • An electrophotographic method and apparatus there for The method is based on optically forming a conductivity image of a master on or in a photoconductive layer which is part of one of two spaced electrodes.
  • An electric field is applied across the space between the electrodes during the formation of the conductivity image causing a migration of charged toner particles in a dispersion occupying the space between the electrodes.
  • a further migration occurs to form a toned image of the master on an image support at one side of the space.
  • Positive or negative images can be formed according to the direction of the field and the sign of the charged particles.
  • the present invention relates to a method of producing pictures.
  • the invention refers to an apparatus for carrying out the method and to a use of the method.
  • a high-voltage corona is required for the charging of the photoconductive layer.
  • the high-voltage corona results in damage or impairment to the photoconductive layer.
  • the object of the present invention is to provide a simple and rapidly operating method for the rapid and precise production of images. preferably for colored images, and also an easily handled apparatus for carrying out the process which does not have the said disadvantages.
  • the present invention relates to a method of producing images in accordance with a master, which method is characterized by the fact that by exposure, as a function of the master, of a photoconductive layer onto or into said layer, there is produced a conductivity image which corresponds to the master and which is utilized to control, within a space adjacent said layer, an electrical field through which charged toner particles are moved, whereby the charge of toner particles which contact the said layer or a support for an image close to it is varied, and in a further method step, upon the disconnecting of the said electrical field, toner particles migrate in accordance with the master to the support for the image.
  • the invention also relates to an apparatus for the carrying out of said process which is characterized by a first electrode and a second electrode, which electrodes may be optionally connected to a source of voltage or to each other, the first electrode having associated with it a photoconductive layer which can be exposed by imaging means in accordance with a master, and a support for an image is arranged on the second electrode and a medium having charged toner particles can be introduced in the space between the two electrodes.
  • the invention also concerns the use of the said process for producing single-colored or multi-colored pictures.
  • the invention furthermore relates to pictures produced by the said method.
  • FIG. 1 is a schematic showing of the apparatus, not drawn to scale
  • FIGS. Ia, lb, 10 show three phases of the generation of the image (cross-hatching to represent transparent material, such as glass, being omitted in element 2 for clarity of FIG. lb,
  • FIG. 2 shows a second diagrammatic embodiment
  • FIG. 3 shows details of a first holding device of embodiment of FIG. 2,
  • FIG. 4 shows a portion of FIG. 3
  • FIG. 5 shows details of a second holding device of the embodiment of FIG. 2.
  • FIG. I is a diagrammatic view of a first embodiment of an apparatus for the carrying out of the said method. This figure shows merely the basic construction of the arrangement in order to explain the manner of operation and is not drawn to scale.
  • a first electrode 1 is formed by a transparent glass plate 2 which is covered on one side by a thin, transparent. conductive layer 3.
  • This conductive layer 3 can consist, for instance. of tin oxide, as is the case in the known NESA glasses.
  • a photoconductive layer 4 for instnace of panchromatically sensitized poly-(N)-vinyl carbazole.
  • the sensitizing can be effected, for instance, by adding a small amount of tetranitrofluorenone (TNF).
  • the thickness of the photoconductive layer 4 is so selected that it absorbs light in the visible spectral range and does so in such a manner that the light activates the layer in its entire thickness.
  • the thickness of the layer is preferably about 10 to 100 pt.
  • a second electrode 5 Facing the photoconductive layer 4 of the electrode 1 and equidistant at a slight distance therefrom. for instance a few tenths of a millimeter, there is arranged a second electrode 5, for instance an aluminum plate.
  • the distance d between the photoconductive layer 4 and the image support 6 is preferably not greater than about 300 t and at most about 2mm.
  • support 6 there is suitable a large number of materials which have suitable values of electric volume resistance and surface resistance, Thus. for instance, nor mal typewriter paper is well suited. but a plastic sheet, a plate of glass. a metallic foil or a textile material such as a woven or knitted fabric can also be used.
  • a dispersion 8 of colored toner particles 9 in an organic liquid 10 of high ohmic value which assumes a given ZETA potential as a result of the addition of a charge-control agent. lnformation as to suitable materials will be given later on.
  • imaging means 12 there is suitable, for instance, a slide projector having a source of light l2A. a condenser l2B, a color slide as master ll and an objective 12C, which are only diagrammatically indicated in FIG. 1.
  • imaging means 12 can be used which produce an image corresponding to a master 11 on the photoconductive layer.
  • the electrode l of the photoconductive layer 4 is connected via a switch 13 either to the one terminal, in the present example the negative terminal. of a source of voltage 14. or to the second electrode 5.
  • the second electrode 5 is connected to the other terminal, in this case to the positive terminal of the source of voltage l4, and preferably also to ground.
  • the dispersion 8 contains toner particles 9 preferably of the order of magnitude of (H to 50 t.
  • the organic liquid 10 preferably has a resistivity of about lO' IU ohm cm.
  • the toner concentration can may approximately within the range from 0.] to 10 percent by weight.
  • the distance between the support 6 and the photoconductive layer 4 is preferably approximately in the range of 20 p, to 500 a. At least during a part of the exposure time of the photoconductive layer 4 an electric field having a fiedl strength of about 1 to l00 volts/AL is present between the two electrodes 1 and 5, depending upon the sensitivity of the photoconductive layer 4 as well as the charge of the toner particles.
  • Color filters for the image produced on the photoconductive layer 4 are to be provided for the production of colored images, namely for the additive primary colors red, green and violet. There are suitable for this purpose, for instance, the following Agfa-Gevaert separation filters:
  • the two electrodes l and 5 are directly connected with each other. i,e., shunted, via the switch 13 which is in its position l3,
  • the colored toner particles 9 are in any desired distribution in the liquid 10. In the present example these toner particles are assumed to have a positive charge.
  • the two electrodes l and 5 are connected to the two poles of the source of voltage 14 via the switch 13 which is now in its position 13''.
  • a pattern of light from the imaging means (not shown) will fall on electrode I.
  • the positive toner articles 9 (cf. FlG. lu) migrate in the direction towards the layer 4 and only those which strike a place on the photoconductive layer which has become conductive by the exposure will give off their positive charge.
  • the particles 9' which impinge upon the noneonductive places retain their charge.
  • the two electrodes l and 5 are again shunted, i.e., directly con nected with each other by the switch 13 which has been brought again into position I3 and the positive particles 9' migrate in the direction towards the electrode 5 which is at zero potential, thus forming on the support 6 a color deposit 9" corresponding to the conductivity image of the photoconductive layer 4.
  • the image support 6 is preferably pulled off laterally, for instance together with the electrode 5 along appropriate guide members (not shown, but described in greater detail subsequently).
  • the first partial color image obtained is dried preferably on its surface, and returned along the guid members to the original position whereupon the process is repeated with another color filter and corresponding toner material and the third partial color image is produced on the image support 6 in analogous fashion with a third color filter and third toner material.
  • the sequence yellow, magenta, cyan which is customary in conventional color printing technique.
  • the photoconductive layer is preferably protected by a thin protective layer against mechanical and chemical attack in order to obtain a longer life of use for this layer.
  • Teflon, SiO or else silicon nitrides are suitable, for instance, for this protective layer.
  • the photoconductive layer 4 on the first electrode 1 must be cleaned before each change in color, which, however, can easily be done due to the merely small quantity of dispersion 8.
  • the finished color image produced with all three partial color images can furthermore be sprayed with a colorless lacquer in order to fix the image and increase its transparency and then it can be dried, for instance by passing it under a source of heat radiation.
  • an infrared filter can preferably be provided, whereby the photoconductive layer 4 is protected against warming up. At the same time an im provement of the reproduction of red in colored pictures can be obtained hereby.
  • the apparatus shown in FIG. 2 is provided, as imaging means 12, with a slide projector the construction of which is known and which is therefore only shown schematically.
  • a color slide serving as master 1] is inserted into the slide projector in the direction indicated by the arrow IS.
  • a shutter I6 is arranged behind the imaging means 12. As shutter I6 there can he used a shutter which is known from use in cameras. The shutter 16 serves to set the exposure time necessary for producing the conductivity image.
  • One of three color filters I8, 1), 20 can be interposed in the beam path 17 of the slide projector, Each of these color filters serves to produce the corresponding color separation or partial color image.
  • color filters 18, I) and 20 there are suitable, for instance, Agfa- Gevaert separation filters red: L599, violet: U43 8, and green: U525.
  • a gray filter 2 which can be inserted where necessary in the path of the beam of light in order to adjust the intensity of illumination in the case of masters of differ ent average brightness in such a manner that the same exposure time is always required, regardless of the master.
  • the beam path I7 is deflected downward onto the first electrode I bearing the photoconductive layer 4, this electrode being arranged horizontally in a first holding device 23.
  • the first electrode 1 and its conductive layer 3 are connected with the switch 13.
  • the first electode I can be connected via the switch 13 either with the one terminal 14A, in this case the negative terminal, of the source of voltage 14 or via a line 25 with the second electrode 5.
  • the second electrode 5 is also connected with the second terminal 148, in this case the positive terminal of the source of voltage 14., and with ground.
  • the second electrode 5 is conductively connected with a second holding device 26.
  • the second holding device 26 is supported for displacement in the direction indicated by the doubleendcd arrow 28 horizontally by guide means such as guide rails 27.
  • the guide rails 27 are supported by hear ing pedestals 29 on a base plate 30 of the apparatus 100.
  • a stop 31 On the lefthand side of the guide rails 27 there is provided a stop 31 which is preferably adjustable and by means of which the left end position of the second holding device 26 can be adjusted in precisely reproducible manner.
  • a loading device 32 is provided on the righthand side of the guide rails 27, a loading device 32 is provided.
  • a sheet of paper can be fed from a supply roll 33 to the second electrode for each image to be produced.
  • driven transport rollers 34 By means of driven transport rollers 34, a strip of paper wound on the supply roll 33 is pulled off.
  • a cutting device 35 which is automatically actuated as a function of the desired format of paper, a corresponding piece is cut off in each case from the said strip and pushed by means of further driven transport rollers 36 onto the electrode 5 of the second holding device 26 in its righthand end (dotted line) position.
  • the second holding device 26 is preferably connected with a vacuum device (not shown in FIG. 2) by means of which the new sheet of paper is fixed on the electrode 5 over suction holes.
  • the apparatus 100 preferably also has a wetting means 37.
  • the wetting means 37 include a storage tank 38 for the wetting agent 39, for instance Isopar G manufactured by the Esso Company.
  • the paper 6 is saturated with said wetting agent 39 so that upon the introduction of the toner no solvent is removed from it by the paper since its concentration would be changed thereby.
  • the storage tank 38 is connected via a line 40 with a pump 4i which feeds the wetting agent 39 via a second line 42 to a two-way valve 43.
  • a two-way valve 43 there is suitable an electromagnetically switchable valve of known construction. From the two-way valve 43, a line 44 extends to a nozzle arrangement 45 under which the second holding device 26 can be passed.
  • the apparatus 100 furthermore has a multiple toner delivery device 46. Each individual color has its own dispensing part associated with it.
  • a first storage tank 47' contains a supply of the toner 48' for the first individual color. Via a line 49' the toner 48' flows to a toner pump 50' and is fed by the latter via a line 51' to a two-way valve 52'.
  • the apparatus 100 also has a cleaning device 56 ar ranged lateral to the first holding device 23. as well as a drying device 57, the second holding device 26 being moved past both of said devices.
  • the cleaning device 56 contains a roller 58 which is movable downward. for instance electromagnetically. said roller being preferably provided with an elastic covering such as rubber or the like.
  • the drying device 57 can be provided. for instance, with heat radiators and possibly with a blower,
  • FIG, 3 shows details of the first holding device 23.
  • the first electrode 1 with the photoconductive layer facing downward, is mounted in a frame 59.
  • the injection nozzles 54', 54" and 54" are so directed with respect to an oblique edge 60 of the first electode 1 that the jet of toner liq uid emerging from them can flow into the space 7 (not shown in FIG. 4) lying below the photoconductive layer 4 and above the second electrode 5.
  • FIG. 5 is a detail view of a second holding device 26.
  • 61 represents a wiper which consists, for instance, of a profiled rubber blade provided with a sharp edge.
  • the wiper 61 serves to clean the photoconductive layer 4 after the production of each partial color image during the movement of the second holding device 26 towards the right.
  • a cleaning roller 62 also serves for the cleaning of the photoconductive layer 4.
  • the second holding device 26 is brought into its righthand end position.
  • the pump 41 and the pumps 50', 50" and 50" are placed in operation and the lamp 12A of the slide projector is energized.
  • the cut sheet is pushed onto the electrode 5 on the holding device 26 by the connecting for a brief time of the drive member for the transport rollers 5.
  • the vacuum device of the second holding device 26 is connected, the sheet of paper is drawn onto the electrode 5 and thereby fixed in its position on the electrode 5.
  • the second holding device 26 is moved to the left, for instance by a motor acting via a rope, a rack or a threaded spindle.
  • wetting agent 39 is sprayed from the nozzle arrangement 45 onto the surface of the sheet of paper lying on the electrode 5.
  • the twoway valve 52' is actuated to the full-line position shown in FIG. 2 for the feeding of toner 48' for the first color so that during the further movement of the second holding device 26 until it reaches the stop 31, the space produced between the photoconductive layer 4 and the second electrode 5 actually the sheet of paper 6 present on it is filled with the first toner 48'.
  • the color filter 18 for the first color is brought into the light path 17.
  • the switch 13 is switched to the terminal 14A of source of voltage 14 in order to produce the electrical field in the space between the two electrodes.
  • the shutter 16 is opened during the exposure time T which is optimum for the first color, whereby a conductivity image corresponding to the first individual color image of the master is produced in and on the photoconductive layer 4.
  • the switch 13 is switched in such a manner that now the first electrode 1 is connected with the second electrode 5. in a fraction of a second there takes place a deposit of color corresponding to the first individual color image on the support 6, i.e. on the sheet of paper lying on the electrode 5.
  • the second holding device 26 is pulled away towards the right laterally from the first holding device 23, whereby the wiper 61 and the cleaning roller 62 remove the toner 48' from the photoconductive layer.
  • the cleaning devicd 56 is temporarily lowered onto the passing support 6 and thus onto the sheet of paper bearing the first color deposit, whereby excess toner 48 which is still adhering to the support 6 is wiped off.
  • the second holding device 26 continues to travel towards the right to a point below the drying device 57 which is temporarily activated and the first partial color image is thereby dried on its surface.
  • the cleaning device 58 is at the same time freed of any adhering toner by the cleaning roller 62.
  • the second color image is produced in a manner similar to production of the first color image.
  • the holding device 26 is moved towards the left, and during its travel below the first holding device 23, the toner 48" for the second partial color image is fed by actuation of the branch valve 52''.
  • the color filter 19 for the second partial color image is brought into the beam path 17.
  • the switch 13 is switched to the terminal 14A of the source of voltage 14.
  • the shutter 16 is opened for the exposure time T which is optimum for the second color, a conductivity image corresponding to the second color image being produced in and/or on the photoconductive layer 4.
  • the switch 13 is switched in such a manner that the first electrode 1 is connected with the second electrode 5. In a fraction of a second there is produced a deposit of color corresponding to the second partial color image on the support 6, i.e. on the sheet of paper already provided with the first color image, the sheet 6 resting on the electrode 5.
  • the second holding device 26 is pulled away towards the right laterally from the first holding device 23, the wiper 61 and the cleaning roller 62 removing the toner 48" from the photoconductive layer 4.
  • the cleaning device 56 is lowered onto the passing support 6 (the sheet of paper bearing the first and the second color deposits), excess toner 48" still adhering to the support 6 is wiped off.
  • the second holding device 26 continues to travel to the right to a point below the drying device 57 which is temporarily activated and the second partial color image is thereby dried on its surface.
  • the cleaning device 58 is simultaneously freed from any adhering toner by the cleaning roller 62.
  • steps 28 to 37 now following analogously corresponding to steps 18 to 27.
  • the above steps 1 to 38 can be achieved by manual actuation of the various parts of the device 100 indicated or else by automatic actuation thereof. There is no difficulty in designing the corresponding drives and controls on basis of the steps which have been described in detail.
  • the individual switch times for the movement of the second holding device 26, for the placing in operation of the coating device 32, the wetting device 37, the toner feed device 46, the cleaning device 56. the drying device 57 and the replacement of the color filters can be controlled. for instance, by means of a cam-controlled programming device.
  • Organic polymers such as polyvinyl carbazole; organic pigments in a suitable layer support, such as phthalocyanin. or inorganic pigments in suitable layer supports, for instance cadmium sulfide, zinc oxide. etc.
  • the layer support consists of a suitable binder, for instance of acrylic resin, styrene resin or similar substances.
  • the particles may be charged positively or negatively.
  • a positive image corresponding to the particles on the support 6 a positive image and in case of the same polarity a negative image if a positive is used in this connection as master. ln corresponding manner, a negative master can be converted into a positive image.
  • support 6 there can be used, for instance. ordinary typewriter paper; plastic foil, for instance Mylar; textile material, whether woven or knitted; glass plate, aluminum foil or some other metal foil or plate.
  • a filmforming material is preferably applied to the support 6 after the production of the three individual color images.
  • a film-forming material there is suitable a lacquer. for instance any acrylic lacquer; a resin, for instance styrene resin; a low-melting polymer, for instance polyethylene'. or a wax. for instance paraffin wax.
  • the application can be effected by customary technique, for instance by spraying. coating, dipping or rolling.
  • a reversal process takes (ii I place, i.e. a negative image is produced from a positive master and a positive image from a negative master.
  • a positive master gives a positive image and a negative master gives a negative image.
  • Example of a photoconductor for the production of the photoconductive layer 4 A a'thick layer of a mixture of polyvinyl carbazole and 3 percent by weight tetranitrofluorenone as sensitizer.
  • ESSO Isopar G
  • Example of a toner 48" (second color; magenta) 10 parts by weight Fanal pink 322/2994 (BASF) are ground together with 90 parts by weight of lsopar G in a bead ball mill for min. 4 g of this concentrate as well as 0.04 g of an 8'70 solution of cobalt decanatc in mineral spirits are made up to l()() g with lsopar G and dispersed in a high-frequency agitator for l() min. In this way there is produced a magenta toner with posi tively charged particles.
  • Example of a toner 48" (third color: cyan) 5 parts by weight Savinyl blue GLS (Sandoz) and 5 parts by weight Irgazin blue 3 GT (CIBA-GEIGY) are ground together with 90 parts by weight of lsopar G in a head ball mill for 30 min. 6 g of this concentrate and 0.04 g of an 8% cobalt decanate solution in mineral spirits are made up of to 100 g with lsopar G and dispersed for H) min. in a high-frequency agitator. In this way there is produced a cyan toner with positively charged particles.
  • Example of a wetting liquid 39 As wetting liquid there is preferably used the same liquid as employed to produce the toner, for instance. a hydrocarbon of high insulating power such as lsopar G (ESSO).
  • a hydrocarbon of high insulating power such as lsopar G (ESSO).
  • the two electrodes 1 and 5 are aligned face to face and the intervening space 7 is filled with the yellow toner 48'.
  • the master I] is projected for 6 see. through a violet filter onto the photoconductor layer 4 and during the same time a voltage of-2.S kv is applied to the NESA layer 3 of electrode 1.
  • the magenta toner 48" is introduced.
  • the master II is projected through a green filter for 6 seconds and at the same time a voltage of 3 kv is applied to the NESA layer 3 of electrode 1.
  • the cyan toner 48" is introduced.
  • the master 11 is projected through a red filter for 6 sec. and at the same time a voltage of l .5 kv is applied to the NESA layer 3 of electrode 1.
  • the dis tance d between the surface of the paper and the surface of the photoconductor is I60 1.1.. After the drying and treatment with the fixing agent. a positive full-color image corresponding to the master II is produced on the support 6.
  • Example of a photoconductor 4 B-phthalocyanin is mixed with a styrene-acrylic resin as binder and applied by coating in the form of a layer of a thickness of 5 a.
  • the pigment/binder ratio is 3: l 0.
  • Example of a toner 48' (color black) 5 ml of Hunt toner concentrate (HUNT CHEMICAL CORPORATION) are diluted to [00 ml with Isopar G and mixed well by agitation. In this way there is produced a black toner with positively charged particles.
  • Example of the production of the image A black-white positive is projected as master 1] for 6 see. without color filter onto the photoconductor layer 4 and at the same time a volate of 3 kv is applied to the NESA layer 3 of electrode 1.
  • the toner 48' of 2b there is produced on the support 6 a positive black-white image with good half tones which corresponds to the master 1].
  • the distance d is 200 a.
  • Example 3a Example of a photoconductor 4 Same as under la.
  • Example of a toner 48' (first color: yellow) 2 g of the printing color paste Nagra 6" (SICPA) as well as 0.04 g of 8% cobalt deeanate solution is spirits of turpentine are made up to g with lsopar G and dispersed for 10 min. in a high-frequency agitator. A yellow toner having positively charged particles is produced.
  • Example of a toner 48" (second color: magenta) 2 g of the printing color paste Nagra red 28" (SICPA) as well as 0.04 g of 8% cobalt decanate solution in spirits of turpentine are made up to I00 g with Isopar G and dispersed for 10 min. in a high-frequency agitator. A magenta toner having positively charged particles is produced.
  • Example of a toner 48" (third color: cyan) 2 of the printing color paste Nagra blue 9 (SICPA) as well as 0.04 g of 8% cobalt decanate solution in spirits of turpentine are made up to 100 g with Isopar G and disperesed for 10 min. in a high-frequency agitator. A cyan toner having positively charged particles is produced.
  • the two electrodes I and 5 are aligned face to face and the space 7 is filled with the yellow toner 48'.
  • the master 1] a colored slide is projected for 6 see. through a violet filter onto the photoconductor layer 4 and a voltage of 2 kv is applied during the same time with the NESA layer 3 of electrode 1.
  • the magenta toner 48" is introduced.
  • the master 11 is projected through a green filter for 6 sec. and at the same time a voltage of-l .8 kv is applied to the NESA electrode.
  • the cyan toner 48" is introduced, the master 1 l is projected for 6 sec. through a red filter. and at the same time a voltage of *-().9 kv is applied to the NESA layer 3 of electrode 1.
  • the distance d is 200 a. After the drying and treating with the fixing agent there is produced on the support 6 a positive full-color image which corresponds to the master 11.
  • a method of producing images in accordance with a master comprising the steps of:
  • step c the exposing of the photoconductive layer, is effected with a color separation of the master, and the toner brought into said space in step (b) is suitably adapted to the color separation, whereby a partial color image of the master is produced.
  • each partial image produced on the support is dried on its surface and preferably after removal of excessive toner as an intervening step (e), the same support then being used in a further cycle of steps (b) through (f) for the production of another partial image until a full color image is obtained.
  • Method according to claim 1 characterized by the fact that paper is used as support for the image.
  • Method according to claim 1 characterized by the fact that plastic is used for the support for the image.
  • Method according to claim 1 characterized by the fact that metal is used as support for the image.
  • Method according to claim 13 characterized by the fact that textile material is used as support for the image.
  • Method according to claim 1 characterized by the fact that the support for the image is wetted before the introduction of the toner into said space.
  • Method according to claim 14 characterized by the fact that said toner particles are dispersed in a discrete solvent and further including the step of wetting the support with a wetting liquid of the same type as the solvent of the toner before said image support comes into contact with the toner,
  • Method according to claim 1 characterized by the fact that, as a further step (f), the support bearing the image is coated in a thin layer, preferably after prior drying as an intervening step (c), with an agent increasing the transparency and durability of the image.
  • Method according to claim 16 wherein the said agent is taken from the group consisting of lacquers, resins, low-melting polymers, and waxes.
  • imaging mcans (12) including a light path (17) for forming a light image of a master (11); a first electrode (1) and a second electrode (5) spaced therefrom; and a voltage source (14); the combination of a switch (13) having two positions, said electrodes being connected across said voltage source with the switch in one position and connected to each other with the switch in the other position,
  • a photoconductive layer (4) associated with said first electrode (I) and adapted to form a conductivity image corresponding to the master upon exposure of said layer (4) to said light image
  • Apparatus according to claim 18, characterized by imaging means (12) having a shutter (16) settablc to given exposure times.
  • color filters being color separation filters such as red L599, violet U438, green U525.
  • Apparatus according to claim 24 characterized by a layer (3) of tin oxide as electrode (1).
  • Apparatus according to claim 18 characterized by an arrangement of photoconductive layer (4) and second electrode (5) such that they are movable with respect to each other.
  • a displaceable holding device receives image support (6) and second electrode (5). and further including guide means (27) for the displacement thereof.
  • Apparatus according to claim 18, characterized by a toner feed device (46) for the feeding of at least one toner fluid (8 or 48', 48", 48") into the space (7) between the two electrodes (1, 5).
  • Apparatus according to claim 37 wherein said means to clean the photoconductive layer (4) comprises a wiper (61) and a roller (62).
  • Apparatus according to claim 56 characterized by a cleaning device (18) for removing excess toner on the image support (6).
  • said cleaning device (56) includes a shiftable roller, and characterized by the fact that a cleaning roller (62) is moved in a path past the photoconductive layer (4) for cleaning thereof, and the cleaning device (56) is arranged in the path of said cleaning roller (62) such that upon passage of the cleaning roller (62) past the cleaning device (56) the shiftable roller (58) thereof is shifted to a position such that it is touched by the passing cleaning roller (62) and thereby stripped of adhering toner.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Molecular Biology (AREA)
  • Electrophotography Using Other Than Carlson'S Method (AREA)
  • Color Electrophotography (AREA)
  • Fax Reproducing Arrangements (AREA)
  • Wet Developing In Electrophotography (AREA)
US373823A 1972-06-30 1973-06-26 Electrode-shunting method of producing electrophotographic pictures and apparatus therefor Expired - Lifetime US3901696A (en)

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CH982972A CH548056A (de) 1972-06-30 1972-06-30 Verfahren und vorrichtung zur elektrophotographischen bilderzeugung und anwendung des verfahrens.

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US (1) US3901696A (fr)
JP (1) JPS542849B2 (fr)
CA (1) CA1025514A (fr)
CH (1) CH548056A (fr)
FR (1) FR2191160B1 (fr)
GB (1) GB1406184A (fr)
SE (1) SE396484B (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3976485A (en) * 1974-09-30 1976-08-24 Eastman Kodak Company Photoimmobilized electrophoretic recording process
US4093456A (en) * 1975-06-25 1978-06-06 Konishiroku Photo Ind., Ltd. Process and device for electrophotographic image generation and application of the process
US4155862A (en) * 1975-06-25 1979-05-22 Konishiroku Photo Ind. Co., Ltd. Liquid developer for color electrophotography and process for preparation of the same
US4179209A (en) * 1977-08-03 1979-12-18 Xerox Corporation Multicolor line screen
US4334002A (en) * 1975-06-04 1982-06-08 Repco Research Pty. Ltd. Image development method
US20090130396A1 (en) * 2007-11-16 2009-05-21 Xerox Corporation Method and system for use in preparing magnetic ink character recognition readable documents

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5194666A (en) * 1975-02-10 1976-08-19 Odeinochosetsukei oyobi bunrikei
JPS5720308Y2 (fr) * 1975-03-24 1982-04-30
CA1092730A (fr) * 1975-11-12 1980-12-30 Joseph R. Kaelin Procede de traitement en continu des boues humides sortant d'une usine d'epuration des eaux d'egout
JPS5372625A (en) * 1976-12-10 1978-06-28 Stanley Electric Co Ltd Picture forming system for electrophotography
JPS5422956A (en) * 1977-07-19 1979-02-21 Mikasa Setsukei Jimushiyo Kk Method of and device for treating sewage
JPS5490854A (en) * 1977-12-28 1979-07-18 Toyo Giken Kk Sanitary sewage purifying device by high concentration oxygen
JPS55113079A (en) * 1979-02-23 1980-09-01 Ricoh Co Ltd Image forming method by photoelectrophoresis

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US3346475A (en) * 1963-02-25 1967-10-10 Australia Res Lab Electrophotographic method using an unsymmetrical ac current during development
US3438706A (en) * 1966-10-07 1969-04-15 Canon Kk Electrophotographic device
US3681064A (en) * 1964-07-23 1972-08-01 Xerox Corp Photoelectrophoretic imaging process employing multicomponent electrically photosensitive particles
US3772013A (en) * 1971-01-06 1973-11-13 Xerox Corp Photoelectrophoretic imaging process employing electrically photosensitive particles and inert particles
US3775107A (en) * 1969-10-31 1973-11-27 Xerox Corp Imaging system
US3776722A (en) * 1966-04-22 1973-12-04 M Cantarano Electrophotographic method of imagewise particle transfer employing alternating modulated field

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3346475A (en) * 1963-02-25 1967-10-10 Australia Res Lab Electrophotographic method using an unsymmetrical ac current during development
US3681064A (en) * 1964-07-23 1972-08-01 Xerox Corp Photoelectrophoretic imaging process employing multicomponent electrically photosensitive particles
US3776722A (en) * 1966-04-22 1973-12-04 M Cantarano Electrophotographic method of imagewise particle transfer employing alternating modulated field
US3438706A (en) * 1966-10-07 1969-04-15 Canon Kk Electrophotographic device
US3775107A (en) * 1969-10-31 1973-11-27 Xerox Corp Imaging system
US3772013A (en) * 1971-01-06 1973-11-13 Xerox Corp Photoelectrophoretic imaging process employing electrically photosensitive particles and inert particles

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3976485A (en) * 1974-09-30 1976-08-24 Eastman Kodak Company Photoimmobilized electrophoretic recording process
US4334002A (en) * 1975-06-04 1982-06-08 Repco Research Pty. Ltd. Image development method
US4093456A (en) * 1975-06-25 1978-06-06 Konishiroku Photo Ind., Ltd. Process and device for electrophotographic image generation and application of the process
US4155862A (en) * 1975-06-25 1979-05-22 Konishiroku Photo Ind. Co., Ltd. Liquid developer for color electrophotography and process for preparation of the same
US4179209A (en) * 1977-08-03 1979-12-18 Xerox Corporation Multicolor line screen
US20090130396A1 (en) * 2007-11-16 2009-05-21 Xerox Corporation Method and system for use in preparing magnetic ink character recognition readable documents

Also Published As

Publication number Publication date
DE2327408B2 (de) 1976-01-15
SE396484B (sv) 1977-09-19
JPS542849B2 (fr) 1979-02-14
JPS4944748A (fr) 1974-04-27
FR2191160A1 (fr) 1974-02-01
DE2327408A1 (de) 1974-01-17
FR2191160B1 (fr) 1977-02-18
CH548056A (de) 1974-04-11
CA1025514A (fr) 1978-01-31
GB1406184A (en) 1975-09-17

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