APPARATUS AND METHOD FOR ELECTROPHOTOGRAPHICALLY PRODUCING COPY HAVING CONTINUOUS-TONE AND OTHER CONTENT

Abstract: Method and apparatus for electrophotographically producing high quality reproductions which contain different content types. A photoconductor image sector is subjected to separate exposures of complementary originals O1 and O2. The exposure of component original O1 from exposure station (13) is selected for good tone-scale reproduction of continuous-tone image portions. The complementary exposure of original O2 from exposure station (23) is selected for high-contrast reproduction of line-type image portions. Photoconductor background areas, which border continuous-tone image portions, are exposed to a discharge level below the system's development level by the high contrast exposure of O2.

Description: APPARATUS AND METHOD FOR ELECTROPHOTOGRJ^PHICALLY PRODUCIN COPY HAVING CONTINUOUS-TONE .AND OTHER CONTENT The Technical Field The present invention relates to electro- photographic reproduction methods and apparatus and more specifically to the improved production of copy (including black-and-white and color reproductions) of the kind having both continuous-tone (e.g. pictorial) and other (e.g. uniform background and/or line-type) content. The Background Art U.S. Patent 4,068,940 discloses apparatus and method for electrophotographically producing repro¬ ductions of continuous tone originals. The approach described in this patent is to expose a continuous tone original onto a primary-charged photoconductor sector and thereafter subject the resulting electro¬ static latent image to a uniform exposure from a separate light source through a half-tone screen. The contrast of the screen pattern exposure is regulated by varying the intensity of the separate light source. This improves the quality of the continuous tone reproduction. As the use of electrophotography progresses, . one goal is to produce high quality electrophoto¬ graphic reproductions that contain a plurality of types of information content, e.g. continuous-tone content, line-type content and uniform background content in a single reproduction. Various problems make attainment of this goal a technical challenge. For example, procedures (such as described in U.S. 4,068,940) which aim to optimize reproduction of continuous tone information are not optimal for repro¬ ducing line-type information (for example alpha- numerics, line drawings, graphs, etc.) or uniform background portions. The problems only worsen when it is desired to make such varying content reproductions with high quality in automated equipment that is capable of continuous operation with good productiv¬ ity. The accommodation of color information, as well as black-and-white information, poses even further problems. The Invention The purpose of the present invention is to provide improved apparatus and techniques for coping with the problems, such as outlined above, that arise in electrophotographically producing high quality reproductions containing such different types of information content. The general concept of the present invention achieves the above-stated purpose and can be expressed as closely related method and apparatus constitutions. The first inventive constitution is a method of producing an.electrophotographic reproduction which is composite image that has continuous-tone informa- tion areas, plain background areas and high-contrast, line-type information areas. This method involves primary-charging a photoconductor sector of size which accommodates the composite image to be reproduced; reflection exposing the sector, at a first exposure level and through a half-tone screen, to a first original component which comprises a light-reflective, continuous-tone information area and a non-reflective area; exposing the photoconductor sector at a second exposure level to a second original component which comprises a mask area located in register with the continuous-tone information area of the first original component and a high-contrast, line-type information area at a location not in register with that continuous-tone area; and developing the composite latent electrostatic image thus formed on the photoconductor sector. ^S ATlό The second inventive constitution is apparatus for producing electrophotographic repro¬ ductions in which a photoconductor is moved long an operative path past: (a) primary charging means, (b) first support means for positioning a continuous tone original, (c) exposing means for producing a half¬ tone-screened light image of an original supported by said first support means on said photoconductor sector and (d) means for developing the electrostatic image on said photoconductor sector, and is characterized as further including (i) second support means for accu¬ rately positioning another original that is complemen¬ tary to said continuous tone original in a location which is registered relative to said operative path, (11) high contrast exposing means for exposing said photoconductor sector to the unscreened light image of the positioned complementary original and (ill) means for synchronizing said first and second exposing means and the movement of said sector so that the image exposures are in predetermined register on said sector. The Drawing Description The subsequent description of preferred embodiments of the present invention refers to the attached drawings wherein: Figure 1 is a schematic side view of one embodiment of electrophotographic apparatus for practice of the present invention; Figure 2 is a schematic side view of another embodiment of electrophotographic apparatus for practice of the present invention; and Figure 3 is a schematic side view of yet another embodiment of electrophotographic apparatus for practice of the present invention. The Description of Embodiments Referring now to Figure 1, the apparatus 20 is adapted, in accord with the present invention, to produce electrophotographic reproductions having screened, continuous-tone image areas of excellent tone-scale, "substantially clean" (i.e. without objectionable density level) background areas and unscreened line-type information areas with high con¬ trast. The apparatus 20 includes a photoconductor 11 (e.g. a belt comprising a photoconductive insulator layer overlying a conductive layer on a support) having one or more image sectors adapted for movement along an operative path past primary charging station 12, the exposure zones E, and E of exposure stations 13 and 23, development station 14 and trans¬ fer station 15. The corona charger at station 12, magnetic brushes at station 14 and transfer roller at station 15 can be of the various types known in the art and equivalent devices can be utilized. The exposure procedure and structure of the present invention first and second component-originals 0, and 0 2 of predetermined format to form a composite reproduction. The component-original 0ι comprises a light reflective continuous-tone area(s) C formed within a non-reflective background area B. One preferred embodiment comprises photographic prints mounted on a light-transmissive plastic support. The component-original O 9 is complementary to 0ι as will be described subsequently. The exposure station 13 includes means for supporting original 0, (e.g. transparent platen 16) at the illumination zone of apparatus 20 and a first illumination source 17 located between the illumina¬ tion zone and the photoconductor 11. Lens means 21 is provided to image the original 0, at the illumina¬ tion zone onto the photoconductor 11 at exposure zone E- . Apparatus 20 includes a half-tone screen 19 located in the optical path of lens L and proximate the exposure zone E,. OMPI The operation of the exposure station 13 is as follows. A photoconductor image sector is moved past the charging station 12, where it receives a uniform primary electrostatic charge, and into exposure zone E,. At this stage illumination source 17 is actuated to illuminate the original 0^ (which is in place on platen 16 with its light-reflective, continuous-tone portions facing the exposure zone E,) . More particularly, sources 17, e.g. xenon flash lamps are energized by an adjustable power source Pi at an intensity level selected for opti¬ mizing tone-scale of the electrostatic latent image formed on the photoconductor by light reflected from the continuous-tone portions C. The second exposure station 23 of apparatus 20 is constructed to expose a second component origi¬ nal O2 at the second exposure zone E2. Station 23 includes a light-transmissive document platen 26, illumination sources 27 (e.g. xenon flash lamps) coupled to a power source P«, mirror 29 and lens means Ln for imaging a component original O2 at exposure zone E2. The component original O2 is predeterminedly constructed to cooperate with original component -, t and for this purpose O2 has mask portions M which prevent source 27 illumination from passing to predetermined portions of exposure zone E 2 (viz. those portions which correspond to portions C of the original 0^. In this manner 0 is complementary to 0, . Positioning structures 21 and 22 are provided respectively at exposure stations 13 and 23 to accu¬ rately position originals on their respective exposure platens and thus accurately locate 0 and 0 rela¬ tive to exposure zones Ei and E 2 . A photoconduc- tor location detector 24 and logic and control unit 25 are provided to coordinate exposure of component original On in register on a common photoconductor image sector with the electrostatic image of a first component original 0, (previously exposed on that photoconductor sector at station E-.) . In embodiments where sources 27 are located to reflectively illuminate component original 0«, the mask portions M can be light-absorptive (e.g. black) or light-transmissive. In such an embodiment, the background portions B 2 of component original o 2 are desirably highly light-reflective (e.g. white) and line-type portions LT are light-absorptive (e.g. black). If desired the illumination sources 27 can be on the opposite side of platen 26 from exposure zone E 2 and in such an embodiment the component original 0 can have light-reflective or opaque mask portions M, light-transmissive background portions &2 and light-blocking line-type portions LT (e.g. black, light-reflective or light-scattering alpha- numerics). As will be understood by those skilled in the art, the background portions B. of component original 0ι can be light-absorptive rather than light-transmissive. The desired function is to mask (e.g. be non-reflective to) source 17 light and thus prevent it from passing to the photoconductor sector corresponding to portions Bi of original 0^. A platen cover formed of light-absorptive material also could be used for this purpose. In a complete cycle of operation apparatus 20, a photoconductor image sector is primary-charged at station 12, transported to exposure zone E, and exposed to component original 0ι by sources 17 as previously described. This provides a screened electrostatic latent image of the desired tone-scale on photoconductor sector portions corresponding to continuous-tone information areas C of component original 0, . The uniform primary charge remains on portions of the photoconductor sector that correspond to background portions B- of original 0.. The photoconductor sector next moves to exposure zone E 2 and when it is in proper alignment with respect to exposure station 23 (as sensed by detector 24), logic unit 25 effects a high-contrast exposure of that photoconductor image sector to complementary component original 0 2 « Thus sources 27 are energized and the photoconductor sector is exposed to 0 2 via lens L 2 and mirror 29 at a high exposure level. This forms a high-contrast, non-screened image of line-type infor¬ mation areas LT and, in addition, discharges the photoconductor image sector portions corresponding to background areas B 2 (to a level below the develop- ment level of apparatus 20). The photoconductor image sector, which now bears the composite electrostatic image, is then developed by magnetic brushes at station 14 and the developed toner image is trans¬ ferred to a copy sheet S at station 15 and fixed to the sheet at fusing station F. Referring now to Figure 2, apparatus 30 provides features and advantages such as previously described in an embodiment capable of producing color or black-and-white reproductions containing different information content types. The apparatus 30 provides reproductions wherein continuous-tone areas have good tone-scale, line-type information areas are of high contrast and background areas are "substantially clean" with respect to unwanted toner deposition. Much of the structure of the apparatus can be as previously described and such portions are indi¬ cated by designators corresponding to those of Figure 1. However, there are significant differences between apparatus 30 and previously-described embodiment which provide additional capabilities e.g., in reproducing color originals or black-and-white reproductions. In * this regard an array 31 of color filters, e.g. includ¬ ing red, green and blue filters, is mounted along the optical path of exposure station 13. The array 31 is indexable by shaft 32 to selectively position each particular color filter in the optical path during the successive color-separation exposures of continuous- tone portions C of a color original 0,. Also in the apparatus 30 embodiment, the development means 14 includes discrete magnetic brush devices 14-1, 14-2, 14-3, 14-4, which are operable, in response to signals from logic and control unit 35, to selectively apply different colors of toner (e.g. cyan, magenta, yellow and black toner) to different photoconductor image sectors. The light source 18, e.g. a xenon flash lamp, is energized by its power source P 2 to provide an exposure level at the photoconductor which substan¬ tially discharges portions of the photoconductor (corresponding -to background B) by transmission exposure. When activated, the intensity of this transmission exposure is selected to reduce the electrostatic charge level of portions corresponding to document background below the development level of the apparatus (e.g. to a level proximate or below the bias on magnetic brushes at development station 14) . The discharge of transmission-exposed photoconductor portions therefore is preferably more than the maximum discharge (minimum development density level) of the reflection-exposed portions. The exposure from source 18 is selected to discharge the screen pattern of screen 19 in the background areas below the development level of the apparatus. The functioning of these additional devices in cooperation with the other structure of electro¬ photographic apparatus 30 will be easily understood by considering the following operational descriptions of its different modes. To commence operation of a color reproduction run, component originals 0ι and 0 2 are prepared and positioned at predetermined positions respectively on platens 16 and 26. In the illustrated embodiment, component original 0, comprises a plurality of color continuous-tone information areas C (e.g. color prints) mounted on a light-transmissive support which forms background areas B, . The component original 0 2 for the Figure 3 embodiment comprises a light- reflective (e.g. white) background B 2 with black mask areas M located in registered complementary relation with areas C of component original 0, and with high-contrast, line-type infotmation LT (e.g. black alphanumeric information) located in adjacent areas on the white support. Index or positioning means, e.g. guide rails 36, 37, are provided to assure proper relative location of the component originals and thus proper register of their light images at exposure stations Ei and E 2 . With the originals 0ι and 0 2 thus prepared and positioned, the operator inputs control data to logic and control unit 35, e.g. by a keyboard (not shown). Such data can include: (1) the desired operational mode (color or black-and-white), (2) desired number of reproductions and (3) special exposure level information regarding the respective color-separation exposures of composite original 0, . With regard to the last-mentioned input data, the operator often will perform pre-runs of the color-separation exposures at varying levels to determine optimum exposure levels for the particular pictorial information involved. Logic and control unit 35 preferably contains memory to store selected exposure levels for each respective color-separation exposure. When the above data is input, a "run" command is actuated by the operator, and the photoconductor belt 11 moves successive photoconductor image sectors thereof past primary charger 12 and onto exposure zone E, . Position of the photoconductor image sectors is detected by a sensor, e.g..a detector D of perfora- tions in the photoconductor, and a position signal is input to unit 35. Logic and control unit 35 effects control of successive red, green and blue color expo¬ sures onto successive photoconductor sectors. For example, such control from unit 35 can include synchronization of: (1) the indexing of filter array 31, (2) energization of power source Pi at the desired level(s) and (3) energization of source P 2 to actuate background clean-up. The three photo¬ conductor image sectors, thus exposed, respectively comprise screened, continuous-tone red, green and blue color-separation electrostatic images corresponding to portions C of the original 0, and background por¬ tions discharged by source 18 to a level below the development level of apparatus 30 (e.g. below the bias level applied to the brushes of stations 14 by means not shown). As the sector bearing the red color- separation electrostatic image moves over magnetic brush 14-1, the brush is activated by unit 35 to apply cyan toner in accordance with the electrostatic image. Similarly brushes 14-2 and 14-3 are activated to apply magenta and yellow toner respectively to the subse¬ quent green and blue electrostatic color-separation images on successive sectors of the photoconductor. As a fourth primary-charged sector of the photoconductor belt 11 passes zone E, , a panchro¬ matic light exposure of selected tone-scale is effected by sources 17, without the activation of source 18. It may be preferred to filter this exposure, e.g. with another element of array 31, to achieve a more panchromatic system response for this exposure. At this stage, the electrostatic pattern on -li¬ the fourth photoconductor image sector includes a screened, continuous-tone latent image pattern of the pictorial areas C and uniform primary charge on other areas corresponding to background B, . The fourth sector moves next to exposure zone E 2 , and, in proper timed relation with movement of belt 11, unit 35 activates sources 27 to effect a high-contrast exposure of component original 0 2 , in register with the image of component original O^ onto the fourth sector. The electrostatic image on the fourth sector leaving zone E 2 thus comprises (1) the continuous- tone electrostatic image component exposed at zone Ei (and undisturbed by the zone E 2 exposure because of mask portions M on original O2) » (2) the high-contrast, unscreened, alphanumeric electrostatic patterns corresponding to areas LT of composite original 0 2 and (3) the clean background portions discharged below the development level. The fourth sector subsequently is developed with black toner by magnetic brush 14-4. In an alternative embodiment, apparatus 30, exposure source 18 is omitted. In such embodiment each frame or sheet is subjected to the exposures from stations 13 and 23 to achieve the desirable effects of continuous tone exposure levels tailored for good tone scale and retained highlight detail and for high contrast background (with or without included line detail). It will be appreciated that logic and control unit 35 can be constructed to effect the above- described exposures of the four photoconductor image sectors in any desired sequence. Also, it will be appreciated that logic and control can effect expo¬ sures so that the line information is in a color(s) other than black. For example, cyan line information can be provided by omitting the source 18 illumination and providing source 23 illumination to the red filter exposed image sector rather than the neutral density exposed sector. Of course the apparatus 30 can employ less than four colors, if desired. After exposure and development and in proper timed relation with movement of the photoconductor image sectors to transfer station 15, unit 35 signals actuation for feeding a copy sheet S to the transfer roller. Successive cyan, magenta, yellow and black toner images are then transferred to the copy sheet, in register, by the first, second, third and fourth image sectors of the photoconductor 11. Unit 35 then signals pick-off of the copy sheet by detack device 39, and copy sheet S is fed through fixing device F to a receiver bin. It will be appreciated that the successive reproductions of the composite original can be made in a continuous mode by repeating the above- described operation as the belt recirculates. Appropriate photoconductor cleaning and rejuvenation (known in the art) can be provided along the return path from station 15 to station 12. Apparatus 30 also can be operated in a black-and-white copy mode. In such operation, appro¬ priate control information is input to unit 35, e.g to select the black-and-white mode, the number of copies desired and any exposure level information for sources 17. Start of the copy run is commanded and control unit 35 effects repeated cycles of charge exposure and development as described above with respect to the fourth (black toner) sector on successive photocon- ductor image sectors. Copy sheet feed in this mode is activated for each photoconductor image sector, in contrast to the color mode where four toner images are transferred between each copy sheet detack and replacement cycle. Figure 3 discloses another embodiment of electrophotographic apparatus 40 in accord with the present invention. Apparatus 40 is similar in functional capabilities to the Figure 2 apparatus, and again, corresponding structural features are indicated with corresponding designators. The apparatus 40 differs from the Figure 2 embodiment primarily with respect to the construction of the photoconductor image sectors and the operative path of the appa¬ ratus. Specifically, the photoconductor image sectors of apparatus 40 are in discrete sheet form and have separate paths within the development portion of the apparatus. In operation in a color copy mode, originals 0ι and 0 2 are prepared as described with respect to Figure 2 and placed in register on platens 16 and 26. Appropriate control signals are input to a con¬ trol and logic unit (not shown) and a start command is actuated. A first sheet sector 11-1 then is fed from a supply, primary-charged and exposed by device 13 via a red filter to original 0ι at zone Ei (in the same manner described with respect to the first photo¬ conductor image sector of the belt 11 of apparatus 30). The sheet 11-1 next is moved past exposure station 23 (without an exposure actuation), is developed by brush 14-1 with cyan toner and is moved to hold position P, . Subsequently green and blue color-separation images are exposed on sheets 11-2 and 11-3 and the resulting electrostatic images are developed by magnetic brushes 14-2 and 14-3 and forwarded to hold positions P 2 and P * . A sheet 11-4 is then primary-charged, exposed at station 13 (by source 17 only) and at station 23 by source 27, all in a manner like that described above regarding the fourth sector of apparatus 30. The composite image on sheet 11-4 is developed with black toner and sheet 11-4 is moved to position P^. From this stage of the operation, the sheets can be forwarded to station 15 in any desired order for transfer of toner to a copy sheet S. As was the case with the Figure 2 embodiment, apparatus 40 can be operated in a black only mode by successively repeating the sheet 11-4 sequence coordinated with successive copy sheet feed for each exposure sequence. For certain applications it may be desirable to provide apparatus like that shown in Figure 3 but without source 18. In such embodiment each frame or sheet is subjected to the exposures from stations 13 and 23 to achieve the desirable effects of continuous tone exposure levels tailored for good tone scale and retained highlight detail and for high contract background (with or without included line detail). Industrial Effect As explained above and illustrated by the exemplary embodiments, the present invention provides a method whereby a first component original having a continuous tone area and a mask area and second compo- nent original having a complementary mask area and high contrast line information area are predeter¬ minedly exposed, in register, onto a photoconductor sector at respective exposure zones. This provides electrophotographic reproductions having good tone scale of the continuous tone information (with desired screening) and high contrast of line-type information (without screening). Highlight information can be reproduced with good fidelity in the continuous tone portion while adjacent backgrounds are free from objectionable density levels. The present invention also provides apparatus for effecting the registered exposures of such complementary first and second com¬ ponent originals in a manner maintaining the above- noted quality advantages in continuous operational modes having the advantages of speed, simplicity and flexibility. ^toTlO

Claims: The Claims 1. A method for producing an electrophoto¬ graphic reproduction including the steps of: (a) uniformly electrostatically charging a photoconductor sector; (b) exposing the charged photoconductor sector to form a half-tone screened, continuous tone image pattern and (c) developing the resultant electrostatic image, characterized in that the photoconductor sector is exposed by means of light reflected from a first- component-original that includes a light-reflective, continuous-tone image area and a bordering, non- reflective background area and in that the image sector is further exposed, in register, to a high con¬ trast light pattern from a complementary second- component-original. 2. The method of claim 1 further character¬ ized in that the complementary, second-component- original includes a mask-area located in a region corresponding to the continuous-tone image area of said first-component-original and a line-type informa¬ tion area in a region corresponding to the background area of said first-component-original. 3. A method for producing an electrophoto¬ graphic reproduction having continuous-tone image areas of good tone-scale and line-type information areas with high contrast, said method comprising: (a) uniformly electrostatically charging a photoconductor image sector; (b) reflection exposing a registered first-component-original, which comprises a light-reflective, continuous-tone, image area and bordering non-reflective background area, through a half-tone screen and onto said charged photo¬ conductor sector, such sector exposure being at imaging exposure levels selected to provide good tone-scale reproduction; S84/00668 -16- (c) exposing a complementary, second- component-original, which comprises a mask-area located in a region corresponding to the continuous-tone image area of said first component-original and a line-type information area in a region corresponding to the background area of said first component-original, onto said photoconductor sector at a high-contrast exposure level, said exposures being registered to form a composite latent electrostatic image on said photoconductor sector; and (d) developing the composite latent electrostatic image on such photoconductor sector. 4. A method for producing a composite electrophotographic reproduction having a continuous- tone, multicolor image area(s) with good tone-scale, background area(s) which are substantially clean from unwanted development and line-type information area(s) of high contrast, said method comprising: (a) uniformly electrostatically charging first, second and third photoconductor image sectors to a predetermined primary charge level; (b) reflection exposing a first-component- original, which comprises a light-reflective, continuous-tone, multicolor image area(s) and bordering, non-reflective background area, onto each of said charged image frames, respectively via different color filters, such reflection exposures of the image sectors being through a half-tone screen and at an exposure level(s) which optimize tone-scale of the resulting electrostatic images; (c) in register respectively with said reflection exposures of said three image sectors, exposing said sectors, at an exposure level optimized for high-contrast reproduction, to the OMPI light Image of a second-component-original that comprises a light masking area(s) that are comple¬ mentary with said continuous-tone area(s) of said first-component-original and other information areas at locations not in register with said continuous-tone areas; (d) developing said three image sectors respectively with different-color toners; and (e) transferring the developed toner images from respective photoconductor image sectors in register onto a copy sheet. 5. Electrophotographic apparatus in which a photoconductor sector is moved along an operative path past: (a) primary charging means, (b) first support means for supporting a continuous tone original, (c) exposing means for producing a half-tone-screened light image of an original on said first support means on said photoconductor sector and (d) means for developing the electrostatic image on said photocon- ductor sector, characterized as further including: (i) second support means for accurately positioning another original that is complementary to said co¬ ntinuous tone original, in a location which is registered relative to said operative path, (ii) exposing means for exposing said photoconductor sector to the unscreened light image of the positioned complementary original and (ill) means for synchroniz¬ ing said first and second exposing means and the move¬ ment of said sector so that the image exposures are in predetermined register on said sector. 6. In electrophotographic apparatus of the type having an operative path along which a photo¬ conductor image sector is moved past apparatus charging, exposing and developing means, the improvement wherein said exposing means comprises: ϊfEAl OMPI !£_ NATlO$Σ (a) a first exposing device including a irst platen means for registering a first component-original in a predetermined position, means for illuminating.a first component-original which is registered at said first platen means, lens means for imaging the illuminated first component-original onto a first exposure zone located along said operative path and a half-tone screen located in the optical path of said lens means and proximate said first exposure zone, said first exposure device being constructed to effect exposure of a photoconductor sector at one of a plurality of exposure levels selectable to optimize tone-scale reproduction of continuous- tone images; and (b) a second exposing device including a second platen means for registering a second component-original in a predetermined position, means for illuminating a second component-original which is registered at said second platen means and lens means for imaging the illuminated second component-original onto a second exposure zone located along said operative path at a position distinct from said first exposure zone, said second exposure device being: (i) synchronized with said first exposing device and the movement of said photoconductor so that the component original images are registered in complementary relation and (ii) constructed tσ effect exposure of a photoconductor sector at an exposure level especially adapted for high-contrast reproduction of line-type images. 7. Electrophotographic imaging apparatus comprising: (a) a plurality of photoconductor image sectors movable along an operative path of said apparatus; -19- (b) means, located along said path, for forming an electrostatic primary charge on photoconductor image sectors moving therepast; (c) first support means for accurately positioning a first-component-original in a first location which is registered relative to said operative path; (d) first exposing means, operative at a first exposure zone along said path for exposing half-tone-screened, different spectral content light images of a first-component-original that is positioned by said first support means, respec¬ tively onto different ones of said primary-charged photoconductor image sectors; (e) second support means for accurately positioning a second-component-original in a second location which is registered relative to said first location and said operative path; (f) second exposing means, operative at a second exposure zone along said path, for exposing at least one of said photoconductor sector to the unscreened light image of a second-component- original that is positioned by said second support means; (g) means for synchronizing said first and said second exposing means and the movement of said photoconductor sectors at said first and second exposure zones so that said exposure by -said second exposing means is in predetermined register with said exposure by said first exposing means; (h) means for developing the exposed photoconductor image sectors respectively with different color toners; and (i) means for transferring said developed toner images in register to a copy sheet. OMPI _ LA*, WIPO . 8. Electrophotographic imaging apparatus comprising: (a) first, second, third and fourth photoconductor image sectors movable along an operative path of said apparatus; (b) means, located along said path, for forming an electrostatic primary charge on photoconductor image sectors moving therepast; (c) first support means for accurately positioning a first component-original in a first location which is registered relative to said operative path; (d) first exposing means, operative at a first exposure zone along said path: (i) for exposing half-tone-screened, red, green, and blue color-separation images of a first-component- original that is positioned by said first support means, respectively onto three of said primary- charged photoconductor image sectors and (ii) for exposing a half-tone-screened, generally- panchromatic image of such first-component- original onto the other of said primary-charged photoconductor image sectors; (e) second support means for accurately positioning a second-component-original in a second location which is registered relative to said first location and said operative path; (f) second exposing means, operative at a second exposure zone along said path, for exposing said photoconductor sectors to the unscreened light image of a second-component-original that is positioned by said second support means; (g) means for synchronizing said first and said second exposing means and the movement of β aid sectors at said first and second exposure zones so that said exposing by said second -21- exposing means is in predetermined register with said exposure by said first exposing means; and (h) means for developing the red, green and blue exposed image sectors respectively with cyan, magenta and yellow toner and for developing said other image sector with black toner. 9. The invention defined in claim 7 wherein said first exposing means is selectively adjustable to vary the levels of its exposure.

Inventors: STOUDT MICHAEL DAVID, STOUDT, MICHAEL, DAVID
Applicants: EASTMAN KODAK CO, EASTMAN KODAK COMPANY
Application year: 1984
Main classification: G03G15
IPC codes: G03G13, G03G15, G03G21