DE2431780A1 - ELECTROPHOTOGRAPHIC COPY DEVICE - Google Patents

Description

Xerox Corporation, Rochester, N.Y./USA Electrophotographic copier

The invention relates to an electrophotographic copier with a light-conducting element, a charging station, a Exposure station and a development station, all for Reproduction of originals act on the light-guiding element.

In the process of electrophotographic duplication as described in US Pat. No. 2,297,691, an electrostatic reproduction is used Latent image recorded on a light-conducting surface

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draws. In the usual procedure, the photoconductive surface is electrostatically charged substantially uniformly and then a light pattern of the reproduced Image exposed, thereby discharging the charge in the irradiated parts of the charged photoconductive surface will. The non-discharged areas of the light-conducting surface thus form an electrostatic latent image in correspondence with the configuration of the original light pattern.

The electrostatic latent image can then be brought into contact be developed with a finely divided electrostatically attractable material such as toner powder. The powder will by the pattern corresponding to the electrostatic charge gradient in the image areas on the light-conducting surface held. Little or no material is deposited where the charge field gradient is lowest. In this way a powder image is generated conforming to a light image of the copy to be reproduced. The powder is then applied to a Transferred a sheet of paper, plastic, or any suitable surface and affixed to it to form a permanent image.

The basic process of electrophotographic duplication can be used to produce color reproductions if the aforementioned basic steps of the process a little be modified. Such color reproductions can be made by repeating the usual technique of (1) charging the photoconductive Surface, (2) exposure through a color component of the original to be reproduced, (3) development of the light-conducting Surface with a suitable toner, (4) transfer the toner image on a carrier material in selected repeated operating cycles. The number of repetitions of the Basic sequence for color reproduction depends on the number of used Colors to develop the image. During each cycle, a different color separation filter is used for selective absorption and thus for the transmission of light of certain wavelengths to the

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light-guiding surface used, whereupon the light-guiding Surface is discharged to a correct extent. After the first exposure, the electrostatic latent image is deposited on the light-conducting surface using a first separation filter then developed by a complementary first color toner. The developed image of the first special color is then applied to the Transfer carrier material. The carrier material, which carries the developed image of the first color, is brought into the position in which it takes pictures that are successively developed with differently colored toners.

After transferring the developed image of the first color the light-conducting surface is then cleaned and evenly charged in preparation for a second exposure: Es a second filter is then inserted into the optical beam path after removing the first filter used, which selectively absorbs and transmits a second color of incident light. The light-guiding surface is so discharged to record a second electrostatic latent image thereon. This electrostatic latent image then becomes moved through a second development station which develops the second image with a second complementarily colored one. The developed image is then superimposed on the substrate transferred to the developed image of the first colored toner already adhering to it.

A color reproduction on the carrier material is then obtained by repeating this process a desired number of times. The carrier material is then moved into a melting area where the colored reproduction is permanently attached. It can three cycles of the process can be used, the process being developed with yellow, magenta and cyan toners. Of course you can more cycles can also be used. In such a three-color system, various color separation filters are used for subtractive generation used in color reproduction. These filters can be red, green, and blue.

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In order to accomplish the above-mentioned technique of color reproduction, it is necessary to provide a multi-color device which has the various necessary filters for
the process begins in the optical beam path of the exposure device in the correct operating sequence. Likewise, it is necessary to use a variety of developing systems for developing preselected electrostatic latent images on the photoconductive surface
and it will be recognized that suitable control means must be provided in order to use the correct color filter with the appropriate development unit
will.

In order to expand the use of the above-mentioned color electrographic duplicating machine, it is necessary to use a control device which enables the independent use of each of the individual filters in combination with each of the
individual development units. In addition, it is necessary to provide the operator with a visual display device through which the resulting copy colors can be viewed in accordance with the associated document colors to be copied, so that the appearance of the final copy can be recognized beforehand without the operator having any special knowledge of color theory owns.

The control device for this should be simple and compact and
be easy to use. The control device should be a retrofit for an already existing device and serve as an add-on or replace an already existing control in a color electrographic copier.

It is the object of the invention to provide an electrophotographic copier of the type described at the outset with a controller
and an indication of the final colors of the copy to be produced
create.

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This task is accomplished by an electrophotographic copier of the type described in the opening paragraph, which is characterized according to the invention by a plurality of development elements in the development station, the developer elements corresponding to different colors and so arranged are that a predetermined one of them is turned on each time, a plurality of different colored optical filters in the exposure station, of which a specific one can be used, and an operating control device for switching on from one of the filters to one of the development elements.

The electrophotographic copier according to the invention an operator control panel with a matrix of optical filters in relation to FIG colored toners, whereby each individual color development system is inactivated independently or alternatively with one or one A plurality of preselected color filters can be used so that accurate color renditions can be produced from multicolored originals can be. Alternatively, colors can be transposed in a predetermined manner. Together with that, the Final color visually by the operator as a function of the setting of the controls prior to making the copy be perceived.

Further features and usefulnesses of the invention emerge from the description of exemplary embodiments on the basis of the figures. From the figures show:

Figure -1 is a perspective view of a color electrograph Copier in which the control device according to the invention is used;

Fig. 2 is a schematic perspective illustration of the color electrographic copier of Fig. 1;

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Fig. 3 is an exploded view of the. Tax income, direction used in the copier shown in Fig. 1;

4 shows an exploded view of the filter device of the copier as it is in FIGS. 1 and 3 is shown; and

FIG. 5 is a circuit diagram of the control panel shown in FIG.

For a general understanding of the electrophotographic reproducing apparatus / in which the invention can be applied, this is first described with reference to the figures. In Fig. 1 is an electrophotographic reproducing apparatus 13 with Control and display device 11 is shown. Although the control and display device 11 according to the invention is particularly good at this type of device can be used, it will be clear from the following discussion that the invention is not only in the particular embodiment shown but in one can be used in a wide range of applications in color electrostatic display devices.

As shown in FIG. 2, the device has a drum 10 a light-guiding surface 12 fixed to it and carried around the outer circumferential surface. The drum '10 is in rotatably mounted on the machine frame and is driven by a drive motor (not shown) with constant angular speed in Driven in the direction of arrow 14. As the drum 10 rotates, the photoconductive surface 12 traverses one by one a number of processing stations. The drive motor rotates the drum 10 at a predetermined speed relative to the other operating mechanisms of the reproducing apparatus. One Clock disk, mounted near one end of the shaft of drum 10, operates with the device logic to synchronize the operations of the various stations are related to the rotation of the drum 10. In this way, the correct operational sequence achieved in the various processing stations. 509814/0990

The drum 10 initially rotates the photoconductive surface 12 towards the charging station A. A charging station A, a corona generator Device, is designated 16 and extends longitudinally in a transverse direction transverse to the light guide surface 12 for creating a relatively high, substantially uniform charge thereon. Preferably the corona generating Apparatus 16 such as that described in US Pat. No. 2,778,946.

After the light-conducting surface 12 on a substantially uniform potential is charged, the drum 10 rotates the photoconductive surface 12 to an exposure station B. Further. In the exposure station B a color-filtered A light image from an original document 22 is projected onto the charged light-conducting surface 12. The Barking Station B has a movable lens system 18 and a color filter meter - mechanism 20 open. A suitable movable lens system is described, for example, in US Pat. No. 3,062,108. The filter mechanism 20 cooperates with the control device 11 to eugen the required photo. The original document 22 such as a paper page, a book page or the like is printed on a transparent printing plate with the to be reproduced Side down. As shown in Figure 2, lamps 26 can be in duty cycle with the lens 18 and the filter mechanism 20 move to successive ■ partial areas of the original document 22, which is on the plate 24 is to be scanned. In this way, a flowing light image is created from the original document 22 onto the light-guiding surface 12 projected. During the exposure process, the filter mechanism 20 places selected color filters in the optical Beam path from the lens 18. The appropriate filter has an effect the light rays imaged by lens 18 to form an electrostatic latent image on the light conducting surface 12 corresponding to a preselected spectral range of the electromagnetic wave spectrum to be recorded, which is described in the following referred to as a single color electrostatic latent image. 509814/0990

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Next, the drum 10 rotates to a development station C. In the development station C, three individual development units 28, 30 and 32 are arranged around the one on the light-conducting Surface 12 to visualize recorded electrostatic latent image. These are preferably the developer units all of the kind referred to in the art as "magnetic brush developer units" will. A typical magnetic brush system uses a magnetizable developer mixture, which includes carrier granules and toner particles having. Generally, the toner particles are thermosetting. During operation, the developer mix is constantly being used directed force flux field passed through it to form a brush therefrom. That recorded on the light-conducting surface 12 electrostatic latent image is brought into contact with the brush of the developer mix. The toner particles become attracted by the developer mixture to the latent image. Each of the developer units contains suitable color toner particles, which is normally the complement of the spectral range of the wavelength of the light transmitted through the filter 20 is equivalent to. For example, a green-filtered electrostatic latent image is created by the deposition of green absorbent Magenta toner particles developed on it, and filtered blue and red Latent images are developed with yellow and cyan toner particles, respectively. In the above operating mode there is the control device 11 in the normal operating mode. With others In modes of operation, however, the control device 11 can change the filters so that the developing units are operated do not contain toner particles which are complementary to the color of the light transmitted therethrough. The resulting The colors of the copy do not match those of the original, but have been changed in the desired way. The control device 11 also shows the colors of the copy so that the operator can Predict the results of the filter change. A typical developer station with a plurality of developer units, as contained in Fig. 2 is in the pending

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2A31780

U.S. Patent Application 255,259, filed in 1972, is described.

After the development, the image now visible is moved on to the transfer station D. In the transfer station D the toner powder, which is electrostatically adhered to the photoconductive surface, becomes a sheet of the final carrier material 34 transferred. The end substrate 34 may include plain paper or a sheet of thermoplastic polysulfone material be. A transfer roller 36 releasably secures the substrate 34 for movement in a recirculation path in order to. The transfer roller 36 is rotatable in the direction of arrow 38 in synchronism with the drum 10 (in this case with essentially the same angular velocity to it). Therefore, a plurality of toner powder images are transferred from the light-conducting surface 12 to the carrier material 34, each toner powder image being superimposed in register with the previous one. The image transfer is effected by a electrically biasing transfer roller 36 at a potential which has such a size and polarity that it electrostatic toner particles from the latent image recorded on the light-conducting surface 12 onto the carrier material 34 attracts. A suitable electrically biasing transfer roller is disclosed in U.S. Patent 3,612,077.

After a plurality of toner powder images from the photoconductive Surface 12 has been transferred to the carrier material 34 is, gripper fingers 40 can the carrier material 34 from the Surface of the transfer roller 36. A wiper strip 42 is then joined between the carrier material 34 and the transfer roller 36. This separates the carrier material 34 from the transfer roller 36, whereby a conveyor 44 transfers the carrier material 34 to a fixing station E can transport further.

In the fixing station E, a melting device 46 permanently fixes the toner powder image on the carrier material 34. A kind of

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A suitable melter is described in pending US patent application Ser. No. 300,531 of 1972 or US Pat
3,498,592. The carrier material 34 with the toner powder image permanently affixed thereon is then transferred via conveyor 48
and 50 advanced to a receiving tray 52. The receiving tray 52 is arranged so that the operator can easily remove the finished copies from the reproduction machine
can.

Before describing the copying process further, the
Sheet feed mechanism briefly described. As shown in FIG. 2, a stack 54 of carrier material 34 is deposited on the tray 56. The feed roller 58 cooperates with the idler roller 60 to move the top sheet from the stack 54 into the
Guide shaft 62. The chute 62 directs the advancing sheet into a nip between register rollers 64 which align the sheet. The register rollers 64 then move the sheet onto the transfer roller 36 where it is moved
is thus retained in a recirculation path.

The last processing station in the direction of rotation of the drum 10 according to the arrow 14 is the cleaning station F. As already stated, the majority of the toner particles are transferred to the carrier material 34, but some residual toner particles remain on the light-conducting surface 12.
The cleaning station F removes these residual toner particles from the photoconductive surface 12. The residual toner particles are initially exposed to the influence of a cleaning, corona-generating device, not shown, which can neutralize the remaining electrostatic charge on the photoconductive surface 12 and the toner particles adhering to it. The neutralized toner particles are then removed from the
photoconductive surface 12 is removed by a rotating fiber brush 66 in contact therewith. One type of suitable brush cleaning device is described in U.S. Patent No. 3,590,412.

In normal operation where the copy is in the same color as the

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If the original is to be reproduced, the filters are sequential used. The development stations containing magenta, cyan and yellow toners are used for successive Developments of the electrostatic latent image recorded on the photoconductive surface 12 are used. Together thus the green filter for exposing the charged light-conducting surface 12 for the magenta development becomes the red filter used for cyan development and the blue filter for yellow development.

If the green filter is placed in the optical beam path, then green from the original document becomes the light-guiding one Surface 12 transferred. The irradiated areas of the light-conducting surface are discharged. The loaded areas are developed with magenta toner particles, i.e. toner particles complementary in color. This toner powder image is then transferred to the carrier material 34.

On the next pass, the red filter is placed in the optical beam path and the green and blue filters are removed, whereby red is transferred from the original to the light conducting surface. Once again the irradiated Areas are discharged, and the charged areas are developed with toner particles complementary to red, i.e. cyan. The cyan powder image is transferred to the substrate 34 with the sheet in register with the first or magenta toner powder image. During the third image pass, the blue filter is placed in the optical beam path and the other filters are used for transmission taken out of the blue light. The charged areas of the photoconductive surface 12 are developed with. yellow toner particles in the same manner as in the first two passes, whereupon it is in register on sheet 34 (in Coverage) is transferred to the first two toner powder images.

As can be seen, the black areas of the orientation absorb

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ginals the light from the three areas of the spectrum in such a way that the image potentials on the light-guiding surface is sufficient to develop all three toners, with the result that a black color appears on the final copy. Where the original was cyan, magenta or yellow, the complementary filter creates an image potential that is used for Development alone in the basic density ranges of the spectrum is sufficient, so that each can only be used in a single color toner of Cyan, magenta, or yellow is reproduced. In areas where the original is red, yellow and magenta toners are used as Result of the absorption of red developed in the green and blue areas respectively. The high reflection in the red area is discharging the light-conducting surface in such a way that the development of cyan in the red areas is inhibited. Discharged in a similar way green areas on the original the light-conducting surface when exposed through the green filter, which the magenta development is inhibited, while the green areas absorb red and blue light, thus providing sufficient Potential is created on the photoconductive surface to allow the development of cyan and yellow. The blue areas are reproduced in magenta and cyan when that is reflected from the original and transmitted through the blue filter blue light discharges the light-conducting surface sufficiently to inhibit the development of yellow. In this way it can be seen how black and six colors including shades of it arise.

Used during normal operation of the electrophotographic reproduction machine one or more of the development cycles are omitted, then obviously black cannot be reproduced, because all three colors are required to reproduce black. The device is usually in the one described above Programmed wisely so that special developments take place sequentially along with special filters. Likewise, omitting a special filter and its complementary color toner eliminates the component of color of the final copy, wherever the eliminated color

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be appear as a whole or as a component of a different color. This can be difficult for an occasional operator give. For example, was the original document completely black and were all development units except the one for cyan in the off position, then that would Red filters can be used to absorb any non-red color components. Only red would appear on the light-conducting surface and all red absorbing images, black in this example, would be developed with the cyan developer, like this that a cyan and white copy would be made. If the original document also contained red and would have the same programming used, then the red from the original would be transmitted through the red filter and discharge the light conducting surface, and no image would be developed from the red information. It is to be understood that an occasional operator with no knowledge of color theory or any visual display could easily be messed up.

When operating in a partial color area or when operating with variations where the original is black and two of the filter passes are omitted, it is sometimes difficult to predict what color the final copy will be will. Obviously, a display device is of great help to an operator.

The control and display device determines which filters are operated and shows the colors of the copy. Up until now, every developer had to work with a special filter, and none existed Display device. The device according to the invention allows the selection of an overall color copy or the use of individual ones Developer with every filter. The device has three operator control development operating levers slots corresponding to the toner colors of cyan, magenta and yellow. These Selector switches can be moved between four positions which represent the filters to be used. These positions represent the blue, green and red filters. It is also one

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Off position provided to complete the development unit turn off. By adjusting these switches appropriately it is thus possible to make each of the developers and their filters ineffective. Every development can be successful with everyone of the three filters are working.

Referring now to Figure 3, the filter mechanism 20 is briefly described. Filter 20 has a housing 68, which is mounted on the lens 18 to be moved together with it during scanning. The housing 68 has a window 70 which is so positioned with respect to the lens 18 is that the light from the original 22 can pass through, thereby making the light conducting surface 12 for recording an electrostatic latent image is irradiated. ^ »The soil and top wall 72 and 74 of housing 68 have a plurality of rails. 76 and 78 on. The rails 76 and 78 extend extending across the full width of the housing 68. Each of the rails can guide a filter in such a way that the filter is guided from a rest position on the right side of the housing into an operating position in the window of the housing, so that light can pass through. The filters are through individual Tension springs 80 are biased into the position in which they are guided into the optical window 70 of the housing. The feathers 80 extend from a pin mounted in each individual rail 78 over shafts on the ceiling of the filter. the Spring 80 runs over a filter frame roller 81 and is at its end in a hole in a protruding part 85 of the filter held. Correspondingly, each filter has a bottom spring 82 which is held on the ground track by a pin and extends via a roller 83 to a second hole in the protruding part 85. A stop pin protruding upwards in the bottom of each lane 76 of each filter locks the filters in a position away from window 70. The selected filter is placed in the optical path of the Housing window 70 by actuating a selected solenoid 84 inserted (in this case one of three solenoid coils) Actuating the selected solenoid coil moves the corresponding

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" ¹⁵ " 2A3178Q

corresponding stop from the track 76 from the stop with the corresponding Filter down so that the springs around the filter bring it into the optical path of the window can. The electrical circuit for operating the appropriate circuit is shown in FIG.

If a filter is inserted in an operating position in window 70, then the filter remains there throughout the scanning of the original. The lens 18 and the lamps 26 can be inserted into the The original position can be returned by a spring after the scanning of the original has been completed. While the Lens and the lamp, the inserted filter is moved out of the operating position, so that a second or subsequent Filters can be used. A return arm 86 is rotatably mounted on a pin 88 on the exterior of the housing 68 to return each filter to its rest position after insertion into window 70. In the wall of the case 68 is a curved slot for receiving a pin 92 on the arm 86, which the arm 86 over a curved Path leads and limits the size of its movement. A pivot arm tension spring 94 is attached to the arm 86. She cocks her arm 86 in the upward direction.

Three parallel slots 96 are provided in the wall of the housing 68, which are so long that a filter can be moved from its rest position into its operating position. Each of the slots 96 corresponds to the highest of the respective rail 76 which carries the filter. The arm 98 is mounted on the bottom of each filter and extends outward therefrom out of the housing via one of the slots 96 corresponding to the respective rail. A stop member 100 is conveniently located on the end of arm 86 for engagement with arm 98 of the corresponding filter when this is in the operating position. The details of the mechanism are set forth in pending U.S. patent application Ser. No. 181,892

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1971, which is incorporated herein by reference. The control device is arranged to operate the appropriate solenoid in conjunction with one of the developer units to such a color copy with the desired colors in it.

In addition, the detailed structure of the control and display device is discussed with reference to FIG. Each of the three Controls is of the four-position slide switch type. Each of the sliding members 102, 104 and 106 is the same Coupled with a single color display panel 108, 110 and 112, respectively, for movement. Becomes any of the individual Slide switch moves, then the associated plate moves with it. Each switch has a control opening 114, 116 or 118 in its color mapping plate. The control port for each plate is via an elongated opening 120, '122, 124, 126, 128 and 130 coupled in a manner other than the associated plate so that movement between the plates in a Can take place slidingly. Each of the plates is on slide rails of the cover plate in the operator control panel of the device assembled.

The lower part of each of the plates has permeable openings 132 of appropriately programmed colors as shown. The groups of openings are in front of one white surface 134 for color reading, while the faceplate of the assembly has seven additional color dots 136, the so are arranged so that they coincide with the openings of the end plates. On one side the colored dots are on the faceplate the color names are attached corresponding to the colored dots 136 indicating the colors that the device can reproduce. In this way, when the side panels are moved with respect to each other, the different permeable ones become colored Openings 132 of the plates brought into alignment according to the position of the sliding elements .102, 104 and 106, so that the position thereon determines the color passage in the color points 136.

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When the sliding elements 102, 104 and 106 as in Fig. 1 diagonally are arranged, they are in normal operating sequence for full color reproduction. Coincide in this way the colors of the permeable openings 132 with the colors on the face plate 138. If the sliding elements 102, and 106 moves, however, then they change the colors appropriately in color dots 136, which makes it easy for an operator to switch the colors obtained in a particular selected copy mode. That enables that the colors of the original can be changed selectively and sensibly by a person who only operates occasionally, that other color compositions and transpositions can be assessed before making a copy. The benefit this control panel brings to the operator can only be achieved without such a display generating control panel if the operator has special knowledge of color theory or is already using the device very often Has.

For example, does someone have an original document depicting an American flag outlined in black, and wish to swap red and blue, then the control panels on the diagonal would be opposite to that shown in the figure Way set. As explained above, normally the sliding element 102 corresponds to the red filter and the cyan toner, the sliding element 104, the green filter and magenta toner; and the sliding element 106, the blue filter and yellow toner. To run To change the flag, it would be necessary to move the slide element 102 to the blue-cyan position, the slide element 104 on the green-magenta position and the slider 106 to the yellow-red position to adjust. In this mode of operation, red and blue would be completely exchanged for one another, while black would be preserved in the original. Such a color transposition would reverse all yellow and cyan areas of the original. That is the main advantage of the display for an occasional operator. The number of filters and toners limits the possibilities this device. 5Q98U / 0990

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Without the use of such a color display, in most cases the operator would be required to experiment hires and first makes copies before such a color transposition could be achieved.

In Fig. 5, an electrical circuit for the control and display device is shown. As shown therein, becomes a three-pole switching current impulse relay used to control the duplicating device 13 (Fig. 1) to switch from the normal operating mode to the operating mode to be controlled by the operator. In normal operation, the relay contacts 140, 142, and 144 are closed and the relay contacts 146, 148 and 150 opened. In this way, slide switches 152, 154 and bridged. This causes power lines 158, 160, 162, '164, 166 and 168 with lines 170, 172, 174, 176, 178 and 180 directly connected, whereby the appropriate solenoids of the filter set are operated independently of the control and display device will. In contrast, when the three-pole switching current impulse relay becomes the operator-controlled Mode of operation is switched, the relay contacts 140, 142 and 144 open and the relay contacts 146, 148 and 150 closed. Thereby, the sliding contacts 152, 154 connect and 156 the power lines 158, 160, 162, 164, 166 and 168 with lines 170, 172, 174, 176, 178 and 180, so that the desired Filter is operated. If, for example, the sliding element 102 is set so that the power line 162 with line is connected, the blue-filtered image with cyan toner particles is thereby developed. If the sliding element 104 is adjusted so that connecting power line 160 to line 172 then the green filtered image is developed with magenta toner particles. Finally, if the slide member 106 is adjusted to connect the line 158 to line 170, then a produces a red-filtered image which is developed with yellow toner particles. - The displacement of the sliding elements 102, 104 and 106 of the corresponding slide switches 152, 154 and 156 results in

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converted combinations of the above.

In summary, it is essential that the colors of the copy be checked by the electrophotographic duplicating machine according to Figures 1 and 2 are controlled. In addition, the device according to the invention enables a display of the resulting colors of the copy, so that even one only occasionally operator receives any desired transmission of the same.

The control and display device according to the invention for a Multi-color electrophotographic duplicating machine advantageously solves these problems.

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Claims (9)

Claims / 1J Electrophotographic copier with a light-conducting Element / a charging station, an exposure station and a developing station / all for reproduction of Acting originals on the light-conducting element, characterized by a plurality of developing elements (28, 30, 32) in the developing station (C), the developing elements (28, 30, 32) corresponding to different colors and being arranged to turn on a predetermined one of them, a plurality of different colored optical ones Filters (20) in the exposure station (B), a specific one of which can be used in each case, and an operating control device for switching on one of the filters with one of the developing elements (28, 30, 32) , 2. Electrophotographic copier according to claim 1, characterized by means (11) for visually displaying the response to the actuation control means by which at least one of the filters with at least one of the decompression elements (28, 30, 32) are switched on, color to be produced on the copy. 3. Electrophotographic copier according to claim 1 or 2, characterized in that the developing devices (28, 30, 32) a first developing unit for depositing cyan toner particles on the exposed photoconductive element (12) in response to being switched on by the operator control device (102, 104, 106) with one of the filters, a second developing unit for depositing magenta toner particles on the exposed photoconductive element (12) in response to being switched on by the operator control unit (102, 104, 106) with one of the filters and a third development 50981 4/0990 unit for depositing yellow toner particles on the exposed photoconductive element (12) in response to the Activation by the operator control device (102, 104, 106) with one of the filters. 4. Electrophotographic copier according to claim 3, characterized characterized in that the optical filter device (20) has a first optical filter for transmitting the blue component of the original to be reproduced, which can be switched on by the operator control device (102, 104, 106) with one of the developing devices (28, 30, 32), a second optical Filter for transmitting the green part of the original to be reproduced, which is from the operator control device (102, 104, 106) with one of the development devices (28, 30, 32) can be switched on, and a third optical filter for Transmission of the red component of the original to be reproduced, which is transmitted by the operator control device (102, 104, 106) one of the development devices (28, 30, 32) can be switched on is, has. 5. Electrophotographic copier according to claim 4, characterized in that the visual display device (11) is a End plate (138) having a plurality of display elements displaying the colors of the original and a plurality has openings suitable for displaying the color of the copy corresponding to the color in the original. 6. An electrophotographic copier according to claim 5, characterized in that the operator control device comprises a voltage source, a plurality of coils for moving the optical filters from its rest position outside the optical beam path of the exposure station (B) into an operating position in the optical Beam path of the exposure station (B) and a plurality of operator-operated switching devices for connecting each the coils with 'the voltage source for moving the filter out of the 509814/0990 Having rest position in the operating position. 7. Electrostatographic copier for generating a
Multi-color copy of a multi-color original with an operator control device for the transposition of colors through the "selection of colors in the copy to represent the colors in."
the original, characterized by means for visually indicating the color to be produced on the copy as a function of the setting of the control means. 8. Electrostatographic copier according to claim 7, characterized by means for producing a plurality of monochrome images on a copy sheet in superimposed application to create a multicolored copy. 9. An electrostatographic copier according to claim 8, characterized in that the operator control device is any
the means for generating a monochrome image for
Making a copy corresponding to the color appearing in the visual display device turns on. 5098U / 0990