Electrostatic color copying machine
United States Patent 1 Wick et al.  
 [ ELECTROSTATIC COLOR COPYING MACHINE [75] inventors: Richard Wick, Munich; Friedrich Bestenreiner, Grunwald; Dieter Giglherger, Unterhaching, all of Germany [73] Assignee: Agfa-Gevaert Aktiengesellschafl,  
 Leverkusen, Germany [22] Filed: Feb. 21, 1974 [2]] Appl. No.: 444,262  
 [30] Foreign Application Priority Data Feb. 21. 1973 Germany 2308651 [52] US. Cl. 355/4 [5 I] Int. Cl 603g 15/06 [58] Field of Search 355/4 [56] References Cited UNITED STATES PATENTS 3.38.623 4/l967 Bixby 355/4 3,709,594 [/1973 Hastwell 355/4 Apr. 22, 1975 Primary Eraminer-John M. Horan Attorney. Agent, or Firm-Michael S. Striker [57] ABSTRACT An electrostatic copying machine wherein successive strips of a multicolored original are scanned by an illu minating unit having a diaphragm with several openings for the passage of light in different colors while the first unit moves relative to the original or vice versa. The light issuing from different openings is projected by a system of lenses and mirrors to impinge onto successive strip-shaped portions of a web or sheet of recording material whereby the light from each opening reaches the recording material between a discrete corona discharge device and an associated nozzle which discharges a fluid carrier for dispersed pigment particles. The recording material is moved relative to the corona discharge devices and nozzles or vice versa. The illuminating unit may employ differently colored light sources or one or more sources of white light in combination with differently colored filters.  
 25 Claims, 6 Drawing Figures PATENIEEAPR22 m5 ssamsorg,  
 MS at 1 ELECTROSTATIC COLOR COPYING MACHINE BACKGROUND OF THE INVENTION The present invention relates to copying machines in general, and more particularly to improvements in electrostatic copying machines for pictorial reproduction of information borne by multicolored originals onto webs and/or sheets of paper or other suitable recording material. Still more particularly, the invention relates to improvements in electrostatic copying machines wherein successive strips or lines of an original are scanned by beams of differently colored light and the beams impinge on successive strip shaped portions or lines of recording material.  
  It is known to illuminate a multicolored original .by means of one or more cathode ray tubes which are in circuit with time-delay elements to insure a satisfactory or acceptable delay between successive color signals which are produced in response to the scanning of an original. This is intended to guarantee a perfect registry of all colors. Such illuminating means are unreliable, inaccurate, complex, expensive and tend to malfunction.  
 SUMMARY OF THE INVENTION An object of the invention is to provide an electrostatic apparatus for the copying of multicolored originals with novel and improved means which insure accurate registry between successively scanned strips or lines of an original and successively reproduced strips or lines on the recording material.  
  Another object of the invention is to provide novel and improved means for illuminating successive stripshaped portions of a multicolored original and novel and improved means for imaging such strip-shaped portions onto recording material.  
  A further object of the invention is to provide a copying machine wherein the information applied to a multicolored original can be reproduced on a larger, smaller or identical scale, wherein successive strips or lines of an original can be imaged by a simple optical system, and wherein the original and/or the recording material may be held at a standstill during copying.  
  An additional object of the invention is to provide a machine for continuous reproduction of color pictures, films, paintings, graphs. charts or the like in color.  
  The invention is embodied in an electrostatic machine for the reproduction of multicolored originais. The machine comprises a first unit which is arranged to illuminate discrete strip-shaped portions or lines of an original in different colors, means for effecting a relative movement between the original and the first unit to thereby illuminate successive strip-shaped portions or lines of the original, guide means for a web or sheet of paper or other suitable recording material, a second unit adjacent to the guide means and including pairs of charging and developing means, one pair for each of the different colors, means for effecting a relative movement between the recording material and the second unit, and optical means for projecting differently colored light rays produced and supplied by the first unit between the charging and developing means of the respective pairs.  
  Each of the charging means may comprise a corona discharge device which serves to uniformly charge successive increments of recording material ahead of the respective developing means during relative movement between the recording material and the second unit.  
  The first unit may comprise at least one source of light (with or without a fluorescent substance) which illuminates the original, a diaphragm (which may also serve as a reflector) having a plurality of openings for light rays issuing from the source and illuminating different strip-shaped portions or lines of the original, and different color selecting means for each of the openings. The color selecting means may constitute discrete filters, or such color selecting means may form integral parts of discrete light sources in the first unit.  
  The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved copying machine itself, however, both as to its construction and its mode of operation, together with additional features and advantages thereof, will be best understood upon perusal of the following detailed description of certain specific embodiments with reference to the accompanying drawing.  
 BRIEF DESCRIPTION OF THE DRAWING FIG. I is a fragmentary schematic vertical sectional view of a copying machine which embodies one form of the invention and wherein the first and second units are respectively movable relative to the original and recording material;  
 FIG. 2 is a sectional view of a modified first unit;  
 FIG. 3 is a sectional view of a further first unit;  
  FIG. 4 is a fragmentary schematic vertical sectional view of a second copying machine wherein the optical means comprises elements mounted on two discrete carriages and the recording material moves relative to the second unit;  
  FIG. 5 is a fragmentary schematic vertical sectional view of a third copying machine wherein the optical means as well as the first and second units are mounted on a single carriage; and  
  FIG. 6 is a fragmentary schematic vertical sectional view of a further copying machine wherein the original and the recording material move with respect to the first and second units.  
 DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. I shows a copying machine having a housing or frame 1 including an embedded inclined transport plate-like support 2 for a multicolored sheet-like or plate-like original 3. The original 3 is assumed to be a sheet whereon the information is represented in several colors. A carriage 9 is mounted for reciprocating movement in the housing 1 behind the support 2 along a path defined by one or more elongated guide rails 4. The carriage 9 is provided with pairs of roller followers 5, 6 and 7, 8 which track the respective rails 4.  
  The carriage 9 supports a first unit including a light source consisting of a plurality of parallel fluorescent tubes 10, II, 12, I3, l4, 15 having envelopes coated with layers 10a 15a of coloring matter. For example. the tubes 10, 11 can produce red light, the tubes 12, I3 can produce green light, and the tubes l4, 15 can produce blue light to respectively complement the customary colors cyan, magenta and yellow which are used in the reproduction of color images. The tubes 10, 11 may be phosphorescent tubes of the type L 40 W/(il produced by the West German firm of Osram. The tubes 12, 13 may be of the type L 40 W/63, and the tubes 14, 15 may be of the type L 40 W/64, also furnished by Osram. Instead of such tubes, one can also employ commercially available properly doped gas discharge tubes which furnish light in the desired color. All that counts is that the unit including the tubes 10-15 should furnish light in colors which are at least substantially complementary to the corresponding colors of the original 3. Minor deviations of complementary colors from the theoretically correct complementary colors can be compensated for by appropriate selection of the color of pigment particles which are used for the making of images in the respective colors.  
  An advantage of light sources which supply light in complementary colors over conventional color filters is that the light output is much higher. This will be appreciated by considering that the unavoidable basic filter loss of approximately 5 percent is compounded by losses in the range of l-30 percent due to the fact that the flanks of the characteristic curve of a filter cannot conform to the desired color of the original with a required degree of accuracy. Such losses are avoided by employing light sources of the type described in connection with FIG. 1. Moreover, the utilization of light sources simplifies the construction of the copying apparatus.  
  However, and as shown in FIGS. 2 and 3, the invention can be practiced with equal advantage by resorting to color selecting means in the form of filters which replace the layers 100-150.  
  H0. 1 further shows that the tubes 10, 11,12,13, l4, l5 are partially surrounded and separated from each other by a reflector or diaphragm 16 having three compartments for tubes -11, 12-13, 14-15 and openings 16a. 16b, 16(- through which light in the respective colors passes toward a fixedly mounted lens 19 forming part of an optical system 19, 20. Each of the openings 16a, 16b, 160 is elongated and transmits light which is being reflected from a strip-shaped portion or line of the original 3 on the support 2.  
  The drive means for moving the carriage 9 forwardly (arrow D) comprises a cable or cord 17 which is trained over a roller 18 in the housing 1 and the leader of which is attached to the core of a reel (not shown) which can be coupled to a rotary output member of the prime mover of the copying machine.  
  In the machine of FIG. 1, the first unit includes the parts 10-16 and the means for effecting a relative movement between the first unit and the original 3 includes the carriage which moves the parts 10-16 with respect to the support 2.  
  During reproduction of information on the original 3, the strips or lines A, B and C of the original are imaged by the fixed lens 19 onto a fixedly mounted mirror 20 which projects the light rays onto the underside of a web 21 of recording material, e.g., paper. The corresponding strips or lines are shown at A, B and C. The web 21 is intermittently transported lengthwise (arrow E) along a horizontal path extending between pairs of advancing rolls 42, 43 and 44, 45. The distances between the openings 16a, 16b. 160, of the diaphragm 16 are selected in such a way that the light ray which is reflected from the strip A of the original 3 reaches the web 21 between a first corona discharge device 23 and a first developing device 26, that the light ray which is reflected from the strip B reaches the web 21 between a second corona discharge device 24 and a second developing device 27, and that the light ray reflected from the strip C reaches the web 21 between a third corona discharge device 25 and a third developing device 28. The corona discharge devices 23-25 and developing devices 26-28 constitute the elements of a second unit which is mounted on a second carriage 22 having roller followers 35, 36 and 37, 38 which track one or more horizontal guide rails 34 mounted in the housing 1 at a level below and in parallelism with the path of the web 21 between the advancing rolls 42, 43 and 44, 45. The speed v of the carriage during reproduction of information onto the web 21 is identical with the speed of the carriage 9 if the reproduction scale is 1:1. As shown, the carriage 22 is coupled to the carriage 9 by a cable or cord 31 which is trained over guide rollers 29, 30 in the housing 1. A helical spring 32 is connected to the carriage 22 by a cable or cord 33 to automatically retract the carriages 9, 22 to a starting position (in which the carriage 9 abuts against a fixed stop 49) when the imaging of an original 3 is completed. The forward movement of carriages 9, 22 is terminated when the carriage 9 actuates a limit switch 50 which arrests the prime mover or disengages the aforementioned coupling between an output member of the prime mover and a reel for the cable or cord 17.  
  Each of the developing devices 26-28 is an elongated strip-shaped twin nozzle or chamber extending transversely across the full width of the web 21 between the advancing rolls 42, 43 and 44, 45. Each nozzel receives developing fluid through a supply conduit 39, and a suction pipe 40 serves to withdraw the excess of developing fluid from the respective nozzle. The developing fluid consists of a dielectric gaseous or liquid carrier for dispersed pigment (e.g., particles of toner) in the respective color. By properly synchronizing the quantities of admitted and evacuated developing fluid in each of the devices 26-28, one insures that the underside of the web 21 carries three fluid layers or blankets which travel at the speed of the web and which initiate an electrophoretic developing process.  
  The web 21 is stored in convoluted condition in the form ofa roll 41 and is being advanced (arrow E) at the speed of advancing rolls 42, 43, 44, 45 at least two of which (e.g.. the rolls 43 and 45) can receive torque from the main prime mover of the copying machine. Stationary guides 46, 47 and 48 may be provided for that portion of the web 21 which travels above the carriage 22. The guide 46 insures that the underside of the web 21 is maintained at a fixed distance from the orifices of nozzles of the developing devices 26-28. The web 21 is assumed to be made of paper one side of which (i.e., that side which faces the carriage 22) is coated with a layer of ZnO.  
 The operation:  
  An original 3 is placed, face down, onto the transparent support 2. The carriages 9 and 22 dwell in their starting positions under the action of the spring 32, and the coupling between the reel for the cable 17 and the prime mover is disengaged. the carriage 9 abuts against the stop 49. The foremost compartment of the diaphragm 16 (for the light sources 10 and 11) is at this time located below the lower edge of the orginal 3 on the support 2, i.e., the strip of light furnished by the light sources 10, 11 is assumed to impinge against the housing 1 below the support 2. Therefore, the strip A is then located to the right of the leader of that portion of the web 21 which is to receive the image of the original 3 on the support 2.  
  The attendant or an automatic starter thereupon actuates the drive means for the carriage 9 so that the cable 17 begins to move in the direction of arrow D and entrains the carriages 9 and 22. The prime mover of the copying machine is assumed to be driven continuously so that the carriages 9, 22 can be set in motion against the opposition of the spring 32 as soon as the coupling for the reel which collects the cable 17 is engaged. The objective lens 19 images successive strips of the original 3 onto the mirror 20 and the latter projects the images onto the web 21. The latter is at a standstill.  
  In view of the provision of color selecting means in the path of light rays, each of the openings 16a, 16b, 16c transmits light of a different color (blue, green or red). As the carriage 22 begins to move relative to the adjacent portion of the web 21, the latter is charged uniformly by the corona discharge device 23. The charge disappears in the region of white and blue portions of the strip A. The red and green portions remain charged and attract particles of pigment furnished by fluid issuing from the nozzle of the developing device 26. The same procedure is repeated while the underside of the web 21 is being swept by the strips 8&#39; (green) and C&#39; (red). The device 24 recharges the web 21 ahead of the strip B. and the device 25 recharges the web ahead of the strip C.  
  Experiments indicate that the just described charging of the web 21 by devices 23-25 is not adversely af&#39; fected by remnants of developing fluid from the preceding copying operation and/or by particles of pigment which already adhere to the web. The image of the original 3 is transferred or reproduced in the form of three series of strips which follow each other and each of which is of a different color.  
  When the reproduction of an original image is completed, the front carriage 9 actuates the switch 50 which disengages the aforementioned coupling so that the carriages 9, 22 cease to move in the direction of arrow D and begin their movement back to the starting positoin (arrow E) under the action of the spring 32. At the same time or prior to return movement of carriage 9 against the stop 49, the advancing means for the web 21 is set in motion (arrow E) so that a fresh portion of the web 21 moves in front of the carriage 22.  
  The copying machine of FIG. 1 occupies little room. especially because the pairs of associated corona discharge and developing devices are closely adjacent to each other. The angular stressing of the lens 19 is negligible, and the paths for light rays passing between A-C and A&#39;-C&#39; are relatively long.  
  The scale of the reproduction can be changed by changing the speed of the carriage 9 relative to the carriage 22 or vice versa.  
  Flg. 2 shows that the strips or lines A. B and C are illuminated by tubular light sources 51, 52, 53, 54, 55, 56 which furnish white light. The color selection is effected by filter elements 57, 58, 59 which consist of glass or a synthetic plastic material. The filter elements 57, 58, 59 are respectively blue, green and red. These filter elements cooperate with the adjacent portions of the reflector 16 to completely confine the respective pairs 51-52, 53-54, 55-56 of light sources.  
  In FIG. 3, the filter elements 62 (red), 61 (green) and 60 (blue) are plate-like bodies which are installed in the respective openings 16c, 16b, 16a the diaphragm 16. The tubular elements 51-56 produce white light.  
  In the apparatus of FIG. 4, the light which is reflected by the lines A. B, C of an original 3 is projected by a mirror 64 which is mounted on a carriage 63 replacing the carriage 9 of FIG. 1. The carriage 63 has roller followers 66, 67 which track one or more guide rails 65. The light sources 10-15 are mounted on the carriage 63 in the same way as shown in FIG. 1 and the support 2 for the original 3 is held in a horizontal plane. A projection or trip 63a at the front end of the carriage 63 actuates a switch 82 by engaging an enlarged portion 83 on the upper contact of the switch 82 when the imaging of an original 3 is completed. The means (e.g., a cable or cord) for moving the carriage 63 at a speed v in a direction to the left, as viewed in the drawing. is not shown in FIG. 4.  
  In order to equalize the optical distances, the light rays projected by the mirror 64 are thereupon projected by a V-shaped double mirror 68, 69 moving in a direction to the left but a half (v/2) the speed of the mirror 64. The carriage for the mirror 68, 69 is shown at 70; this carriage has roller followers 71 (only one shown) tracking the guide rail or rails 65. The means for moving the carriage 70 at half the speed of the carriage 63 may comprise a block and tackle or the like, not shown.  
  The light rays projected by the mirror 69 are focussed by a fixed objective lens 72 and impinge upon a web 21 which is being withdrawn at intervals from a roll 41.  
  The corona discharge devices 23-25 and the developing devices 26-28 are fixedly mounted adjacent to the path of the web 21. Masks 215 are provided to insure reliable separation of light rays which are to form the strips A, B and C. During imaging of an original 3 (i.e., while the carriage 63 moves at the speed v and the carriage 70 moves at the speed v/2), the web 21 is advanced by two driven rolls 77, 78 to move lengthwise at the speed r of the carriage 63. The reference characters 73, 74, 75 and 76 denote fixed guide elements for the web 21 in the region upstream and downstream of the advancing rolls 77, 78.  
  The web 21 is preferably severed in automatic response to completion of lengthwise movement through a distance which is necessary to complete the reproduction of the image of an orginal 3. The aforementioned switch 82 can actuate a motor (e.g., an electromagnet 81 having a reciprocable armature) which causes a movable knife to move toward a stationary counterknife 79 and to thereby sever the web 21 as soon as the carriage 63 reaches the end of its forward stroke. The rolls 77, 78 automatically advance the severed portion of the web 21 into a tray or the like, not shown, and the leader of the web 21 on the roll 43 is thereupon threaded through the fixed guide means including the elements 73, 74 to reach the nip of the advancing rolls 77, 78. In the meantime, the carriages 63, 70 have returned to their starting positions, the electromagnet 81 is deenergized, and the drive for the rolls 77, 78 is at a standstill so that the machine embodying the structure of FIG. 4 is ready for the next copying operation.  
  The severing means 79-82 insures that the material of the web 21 is not wasted during the interval following completion of scanning and preceding completion of the developing step.  
  FIG. shows a copying machine wherein the light sources 1-15, the diaphragm 16, the corona discharge devices 23-25 and the developing devices 26-28 are mounted on a common carriage 84 having sleeve-like followers 85, 86, 87, 88 which are slidable on elongated guide rails 89, 90. The original (e.g., a page of a book 93) is placed onto the transparent horizontal support 2 which is mounted in the housing of the copying machine at a level above the light sources -15. A sheet I21 of recording material is held at a standstill while the carriage 84 performs a forward stroke (arrow H) at a speed 1. The carriage 84 further supports a twin mirror 94, 95 and an objective 9l located in front of a mirror 92 which is disposed in the focal plane of the objective. When the imaging of information on a selected page of the book 93 is completed, the sheet I21 is moved lengthwise (arrow E) by advancing rolls 96, 97 so as to issue from the housing by passing through a discharge opening therein. The machine of FIG. 5 is designed to reproduce images of successive originals onto discrete sheets 12] rather than onto successive sections of a continuous web. The mechanism for feeding sheets 121 to the advancing rolls 96, 97 is of known design and is not shown in the drawing. It is clear, however, that the machine of FIG. 5 can copy information onto a continuous web, which can be severed in a manner described in connection with FIG. 4, as soon as the carriage 84 reaches the end of its forward stroke.  
  The plane of the sheet 121 in its guide means between the advancing rolls 96, 97 is parallel to and is located below the plane of the original on the support 2. The optical means 91, 92, 94, 95 is mounted between the two planes.  
  FIG. 6 shows a fourth copying machine wherein the original 3 is moved lengthwise at a constant speed v by means of transporting rolls 98, 99 along a path defined by stationary guide elements 100, I01, 102, I03, 104. The web 21 is moved lengthwise at the same constant speed by means of advancing rolls 105, I06 and along a path defined by stationary guide elements 107, I08, 109, H0, 111. The housing of the copying machine supports a fixedly mounted lens 112, a first mirror 113, a second mirror H4, and a third mirror 115. The mirror 115 projects the strip-shaped images A, B, C against the lens 112 and mirror I13, and the latter projects the images onto the mirror 114 which changes the direction of light rays so that the strips A, B, C are directed against the underside of the web 21 between the devices 23, 26 for A, between the devices 24, 27 for B and between the devices 25, 28 for C. It will be noted that the operation of apparatus of FIG. 6 is quite similar to that of the apparatus shown in FIG. 5 except that the structure of FIG. 5 occupies less room and insures a more satisfactory utilization of the objective. On the other hand, the angular stressing of the objective 112 is less pronounced because the imaging field A-C is more expanded than in FIG. 5.  
  In FIG. 6, the corona discharge devices 23-25 and the developing devices 26-28 are fixedly mounted in the housing of the copying machine. However, in contrast to the mounting of FIG. 1, the developing fluids are discharged downwardly against the upper side of the web 21. Both constructions are desirable when the apparatus employs electrophoretic applicators. The plane of the web 21 in FIG. 6 is parallel to the plane of the original 3, and the optical system 112-115 is installed between the two planes above the original.  
  The improved copying machine is susceptible of many additional modifications. As explained in connection with FIG. 5, the images can be transferred onto discrete sheets 12] which are removed seriatim from a stack on a platform or the like. Also, the invention can be embodied in a copying machine for indirect electrophotography which employs a reusable recording material and wherein the development is followed by image reversal, or in a machine with reversal of charge.  
  Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features which fairly constitute essential characteristics of the generic and specific aspects of out contribution to the art and, therefore, such adaptations should and are intended to the comprehended within the meaning and range of equivalence of the claims.  
  What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:  
  1. In an electrostatic machine for the reproduction of multicolored originals, a combination comprising a first unit arranged to illuminate discrete strip-shaped portions of an original in different colors; means for effecting a relative movement between the original and said first unit to thereby illuminate successive strip-shaped portions of the original in each of said different colors; guide means for a web or sheet of recording material; a second unit adjacent to said guide means and including pairs of charging and developing means, one pair for each of said different colors; means for effecting a relative movement between the recording material and said second unit; and optical means for directing differently colored light rays produced by said first unit between said charging and developing means of the respective pairs, wherein each of said charging means comprises a corona discharge device arranged to uniformly charge successive increments of said recording material ahead of the respective developing means during relative movement between said second unit and the recording material.  
  2. In an electrostatic machine for the reproduction of multicolored originals. a combination comprising a first unit arranged to illuminate discrete strip-shaped portions of an original in different colors; means for effecting a relative movement between the original and said first unit to thereby illuminate successive strip-shaped portions of the original in each of said different colors; guide means for a web or sheet of recording material; a second unit adjacent to said guide means and including pairs of charging and developing means, one pair for each of said different colors; means for effecting a relative movement between the recording material and said second unit; and optical means for directing differently colored light rays produced by said first unit between said charging and developing means of the respective pairs, wherein said first unit comprises at least one source of light arranged to illuminate the original, a diaphragm having a plurality of openings for light rays issuing from said source and illuminating different strip-shaped portions of the original, and different color selecting means for each of said openings.  
  3. In an electrostatic machine for the reproduction of multicolored originals, a combination comprising a first unit arranged to illuminate discrete strip-shaped portions of an original in different colors; means for effecting a relative movement between the original and said first unit to thereby illuminate successive strip-shaped portions of the original in each of said different colors; guide means for a web or sheet of recording material; a second unit adjacent to said guide means and includ ing pairs of charging and developing means. one pair for each of said different colors; means for effecting a relative movement between the recording material and said second unit; and optical means for directing differently colored light rays produced by said first unit between said charging and developing means of the respective pairs, wherein said means for effecting a relative movement between said first unit and the original comprises a first mobile carriage for said first unit and said means for effecting a relative movement between the recording material and said second unit comprises a second mobile carriage for said second unit, and further comprising drive means for moving said first and second carriages at a speed ratio corresponding to the scale of reproduction of the original on recording material.  
  4. In an electrostatic machine for the reproduction of multicolored originals. a combination comprising a first unit arranged to illuminate discrete strip-shaped portions of an original in different colors; means for effecting a relative movement between the original and said first unit to thereby illuminate successive strip-shaped portions of the original in each of said different colors; guide means for a web or sheet of recording material; a second unit adjacent to said guide means and including pairs of charging and developing means, one pair for each of said different colors; means for effecting a relative movement between the recording material and said second unit; and optical means for directing differently colored light rays produced by said first unit between said charging and developing means of the respective pairs, wherein said means for effecting a relative movement between the original and said first unit comprises a mobile carriage for said first unit and said optical means comprises at least one mirror mounted on said carriage and arranged to project light in said different colors.  
  5. In an electrostatic machine for the reproduction of multicolored originals. a combination comprising a first unit arranged to illuminate discrete strip-shaped portions of an original in different colors; means for effecting a relative movement between the original and said first unit to thereby illuminate successive strip-shaped portions of the original in each of said different colors; guide means for a web or sheet of recording material; a second unit adjacent to said guide means and including pairs of charging and developing means, one pair for each of said different colors; means for effecting a relative movement between the recording material and said second unit; and optical means for directing differently colored light rays produced by said first unit between said charging and developing means of the respective pairs, wherein said optical means comprises an objective, a first mirror located behind said objective, a second mirror arranged to project light from said first unit into said objective whereby such light is reflected by said first mirror back through said objective, and a third mirror arranged to project light from said objective to said second unit, further comprising a support for maintaining the original in a plane which is parallel to the plane of recording material, said optical means being disposed between said planes, wherein said means for effecting a relative movement between the original and said first unit and said means for effecting a relative movement between the recording material and said second unit comprise a mobile carriage for said first and second units and said optical means.  
  6. In an electrostatic machine for the reproduction of multicolored originals, a combination comprising a first unit arranged to illuminate discrete strip-shaped portions of an original in different colors; means for effecting a relative movement between the original and said first unit to thereby illuminate successive strip-shaped portions of the original in each of said different colors; guide means for a web or sheet of recording material; a second unit adjacent to said guide means and including pairs of charging and developing means, one pair for each of said different colors; means for effecting a relative movement between the recording material and said second unit; and optical means for directing differ ently colored light rays produced by said first unit between said charging and developing means of the respective pairs, wherein said first unit comprises a re flector having several openings one for each of said different colors, and a plurality of tubular light sources between said reflector and the original so that light issuing from said sources and impinging on the original is reflected by the original and issues through said openings.  
  7. In an electrostatic machine for the reproduction of multicolored originals, a combination comprising a first unit arranged to illuminate discrete strip-shaped portions of an original in different colors; means for effecting a relative movement between the original and said first unit to thereby illuminate successive strip-shaped portions of the original in each of said different colors. guide means for a web or sheet of recording material; a second unit adjacent to said guide means and including pairs of charging and developing means. one pair for each of said different colors; means for effecting a relative movement between the recording material and said second unit; and optical means for directing differently colored light rays produced by said first unit between said charging and developing means of the respective pairs, wherein each of said charging means comprises a device arranged to uniformly charge successive increments of said recording material ahead of the respective developing means during relative movement between said second unit and the recording material.  
  8. A combination as defined in claim 7 wherein said first unit comprises at least one source of light arranged to illuminate the original, a diaphragm having a plurality of openings for light rays issuing from said source and illuminating different strip-shaped portions of the original, and different color selecting means for each of said openings.  
  9. A combination as defined in claim 7, wherein said color selecting means are filters.  
  10. A combination as defined in claim 7 wherein said light source comprises a plurality of discrete light sources arranged to furnish light in colors which are complementary to a plurality of basic colors of the original.  
  11. A combination as defined in claim 10, wherein each of said discrete light sources comprises at least one tubular light emitting element arranged to furnish light in the respective complementary color, said color selecting means forming part of the respective light emitting elements.  
  12. A combination as defined in claim 7, wherein each of said developing means comprises an electrophoretic developing device.  
  13. A combination as defined in claim 12, wherein each of said developing devices comprises an elongated strip-shaped body extending transversely of the carrier material and means for positively circulating a pigment carrying developing fluid in said body.  
  14. A combination as defined in claim 7, wherein said means for effecting a relative movement between said first unit and the original comprises a first mobile carriage for said first unit and said means for effecting a relative movement between the recording material and said second unit comprises a second mobile carriage for said second unit, and further comprising drive means for moving said first and second carriages at a speed ratio corresponding to the scale of reproduction of the original on recording material.  
  15. A combination as defined in claim 7, wherein said means for effecting a relative movement between the original and said first unit comprises a mobile carriage for said first unit and said optical means comprises at least one mirror mounted on said carriage and arranged to project light in said different colors.  
  16. A combination as defined in claim 7, wherein said optical means comprises an objective. a first mirror located behind said objective, a second mirror arranged to project light from said first unit into said objective whereby such light is reflected by said first mirror back through said objective, and a third mirror arranged to project light from said objective to said second unit.  
  17. A combination as defined in claim 16, further comprising a support for maintaining the original in a plane which is parallel to the plane of recording material, said optical means being disposed between said planes.  
  18. A combination as defined in claim 17, wherein said means for effecting a relative movement between the original and said first unit and said means for effecting a relative movement between the recording material and said second unit comprise a mobile carriage for said first and second units and said optical means.  
  19. A combination as defined in claim 7, wherein said optical means comprises a fixed objective, first mirror means for projecting light from said first unit into said objective, and second mirror means for projecting light from said objective into said second unit, and further comprising means for supporting the original at a level below said guide means.  
  20. A combination as defined in claim 19, wherein said supporting means and said guide means are arranged to maintain the original and the recording material in parallel planes.  
 2]. A combination as defined in claim 20, wherein said means for effecting a relative movement between the original and said first unit comprises means for transporting the original with respect to said first unit and said means for effecting a relative movement between the recording material and said second unit comprises means for advancing the recording material with respect to said second unit.  
  22. A combination as defined in claim 1 for the reproduction of originals on a web of recording material, wherein the recording material is stored in convoluted form and further comprising means for advancing the web lengthwise upon completion of each relative movement between said second unit and the web and means for severing the web upon completion of each relative movement between the web and said second unit to thus separate the exposed and developed portion from the remainder of the web.  
  23. A combination as defined in claim 7, wherein said first unit comprises a reflector having several openings, one for each of said different colors, and a plurality of tubular light sources between said reflector and the original so that light issuing from said sources and impinging on the original is reflected by the original and issues through said openings.  
  24. A combination as defined in claim 7, wherein each of said developing means comprises a nozzle having at least one orifice facing one side of recording material in said guide means and means for feeding to said nozzle a fluid carrier for dispersed particles of pigment.  
  25. in an electrostatic machine for the reproduction of multicolored originals, a combination comprising a first unit arranged to simultaneously illuminate a plurality of discrete stripshaped portions of an original in different respective colors; guide means for guiding a web or sheet of recording material along a predetermined path; a second unit adjacent to said guide means and including pairs of charging and developing means, one pair for each of said different colors, said pairs being spaced from each other along said predetermined path; optical means for converting the differently colored light rays derived by said first unit from said plurality of strip-shaped portions into a corresponding plurality of concurrent strip-shaped images each located intermediate the charging means and developing means of a respective one of said pairs, with each strip-shaped image being oriented transverse to said predetermined path; means for effecting a relative movement between the original and said first unit to thereby illuminate successive strip-shaped portions of the original in each of said different colors; and means for effecting between the recording material and said second unit a relative movement corresponding to said relative movement between the original and said first unit.